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-rw-r--r--src/CMakeLists.txt23
-rw-r--r--src/common.c14
-rw-r--r--src/common.h8
-rw-r--r--src/embed.h19
-rw-r--r--src/image.c101
-rw-r--r--src/image.h20
-rw-r--r--src/main.c33
-rw-r--r--src/png/CMakeLists.txt8
-rw-r--r--src/png/LICENSE21
-rw-r--r--src/png/lodepng.c6464
-rw-r--r--src/png/lodepng.h1977
11 files changed, 188 insertions, 8500 deletions
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f5d8646..a3fdafb 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,14 +3,29 @@ find_package(SameBoy REQUIRED)
find_package(SameBoyBootRom REQUIRED)
find_package(SameBoyTemplate REQUIRED)
-include_directories(${SAMEBOY_INCLUDE_DIRS})
+if (USE_LIBPNG)
+ find_package(libpng REQUIRED)
+ add_compile_definitions(USE_LIBPNG)
+ set(PNG_INCLUDE_DIRS ${LIBPNG_INCLUDE_DIRS})
+ set(PNG_LIBRARIES ${LIBPNG_LIBRARIES})
+else()
+ find_package(lodepng REQUIRED)
+ add_compile_definitions(USE_LODEPNG)
+ set(PNG_INCLUDE_DIRS ${LODEPNG_INCLUDE_DIRS})
+ set(PNG_LIBRARIES ${LODEPNG_LIBRARIES})
+endif()
-add_subdirectory(png)
+include_directories(${SAMEBOY_INCLUDE_DIRS})
list(APPEND
THUMBNAILER_SOURCES
+ ${CMAKE_CURRENT_SOURCE_DIR}/common.c
+ ${CMAKE_CURRENT_SOURCE_DIR}/common.h
+ ${CMAKE_CURRENT_SOURCE_DIR}/embed.h
${CMAKE_CURRENT_SOURCE_DIR}/get_image_for_rom.c
${CMAKE_CURRENT_SOURCE_DIR}/get_image_for_rom.h
+ ${CMAKE_CURRENT_SOURCE_DIR}/image.c
+ ${CMAKE_CURRENT_SOURCE_DIR}/image.h
${CMAKE_CURRENT_SOURCE_DIR}/main.c
${SAMEBOY_BOOTROM_SOURCES}
${SAMEBOY_TEMPLATE_SOURCES}
@@ -22,7 +37,9 @@ add_executable(sameboy-thumbnailer ${THUMBNAILER_SOURCES})
add_dependencies(sameboy-thumbnailer sameboy_bootrom sameboy_template)
-target_link_libraries(sameboy-thumbnailer LINK_PUBLIC lodepng)
+target_include_directories(sameboy-thumbnailer PUBLIC ${PNG_INCLUDE_DIRS})
+
+target_link_libraries(sameboy-thumbnailer LINK_PUBLIC ${PNG_LIBRARIES})
target_link_libraries(sameboy-thumbnailer LINK_PUBLIC ${SAMEBOY_LIBRARIES})
target_link_libraries(sameboy-thumbnailer LINK_PUBLIC ${CMAKE_DL_LIBS})
target_link_libraries(sameboy-thumbnailer LINK_PUBLIC m)
diff --git a/src/common.c b/src/common.c
new file mode 100644
index 0000000..959cbf6
--- /dev/null
+++ b/src/common.c
@@ -0,0 +1,14 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "common.h"
+
+void* local_malloc(size_t size)
+{
+ void* mem = malloc(size);
+ if (!mem) {
+ fprintf(stderr, "Failed to allocate memory\n");
+ exit(-1);
+ }
+ return mem;
+} \ No newline at end of file
diff --git a/src/common.h b/src/common.h
new file mode 100644
index 0000000..06d8c27
--- /dev/null
+++ b/src/common.h
@@ -0,0 +1,8 @@
+#ifndef COMMON_H
+#define COMMON_H
+
+#include <stddef.h>
+
+void* local_malloc(size_t size);
+
+#endif \ No newline at end of file
diff --git a/src/embed.h b/src/embed.h
new file mode 100644
index 0000000..12eea23
--- /dev/null
+++ b/src/embed.h
@@ -0,0 +1,19 @@
+#ifndef EMBED_H
+#define EMBED_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+extern const uint8_t cgb_boot_bin[];
+extern const size_t cgb_boot_bin_size;
+
+extern unsigned char CartridgeTemplate_png[];
+extern unsigned int CartridgeTemplate_png_size;
+
+extern unsigned char ColorCartridgeTemplate_png[];
+extern unsigned int ColorCartridgeTemplate_png_size;
+
+extern unsigned char UniversalCartridgeTemplate_png[];
+extern unsigned int UniversalCartridgeTemplate_png_size;
+
+#endif \ No newline at end of file
diff --git a/src/image.c b/src/image.c
new file mode 100644
index 0000000..dd52b95
--- /dev/null
+++ b/src/image.c
@@ -0,0 +1,101 @@
+#include "image.h"
+#include "common.h"
+
+unsigned decode32(uint32_t** out, unsigned* w, unsigned* h,
+ unsigned char* in, size_t insize)
+{
+#if defined(USE_LIBPNG)
+ unsigned retval = 1;
+
+ FILE* fp = fmemopen(in, insize, "rb");;
+ png_bytep* row_pointers = NULL;
+
+ if (insize < 8 || png_sig_cmp(in, 0, 8)) abort();
+
+ png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ png_infop info = png_create_info_struct(png);
+
+ if(setjmp(png_jmpbuf(png))) goto cleanup;
+
+ png_init_io(png, fp);
+ png_read_info(png, info);
+
+ if(png_get_bit_depth(png, info) == 16) png_set_strip_16(png);
+
+ *w = png_get_image_width(png, info);
+ *h = png_get_image_height(png, info);
+
+ png_byte color_type = png_get_color_type(png, info);
+
+ if(color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb(png);
+
+ if(png_get_valid(png, info, PNG_INFO_tRNS))
+ png_set_tRNS_to_alpha(png);
+
+ row_pointers = local_malloc(sizeof(png_bytep) * *h);
+ *out = local_malloc(sizeof(**out) * (*w * *h));
+ for(int y = 0; y < *h; y++)
+ {
+ row_pointers[y] = (png_byte*)(*out+((*w)*y));
+ }
+
+ png_read_image(png, row_pointers);
+
+ retval = 0;
+
+ cleanup:
+ png_destroy_read_struct(&png, &info, NULL);
+
+ if (fp) fclose(fp);
+ if (row_pointers) free(row_pointers);
+
+ return retval;
+#elif defined(USE_LODEPNG)
+ return lodepng_decode32((unsigned char**)out, w, h, in, insize);
+#else
+ #error "No decode implementation"
+#endif
+}
+
+unsigned encode32_file(const char* filename, const uint32_t* image, unsigned w, unsigned h)
+{
+#if defined(USE_LIBPNG)
+ /* create file */
+ FILE *fp = fopen(filename, "wb");
+ png_bytep* row_pointers = NULL;
+
+ /* initialize stuff */
+ png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ png_infop info_ptr = png_create_info_struct(png);
+ if(setjmp(png_jmpbuf(png))) goto cleanup;
+
+ png_init_io(png, fp);
+
+
+ png_set_IHDR(png, info_ptr, w, h,
+ 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+ png_write_info(png, info_ptr);
+
+ row_pointers = local_malloc(sizeof(png_bytep) * h);
+ for(int y = 0; y < h; y++)
+ {
+ row_pointers[y] = (png_byte*)(image+(w*y));
+ }
+
+ png_write_image(png, row_pointers);
+
+ png_write_end(png, NULL);
+
+ cleanup:
+
+ free(row_pointers);
+ fclose(fp);
+#elif defined(USE_LODEPNG)
+ return lodepng_encode32_file(filename, image, w, h);
+#else
+ #error "No encode implementation"
+#endif
+} \ No newline at end of file
diff --git a/src/image.h b/src/image.h
new file mode 100644
index 0000000..1a9aeae
--- /dev/null
+++ b/src/image.h
@@ -0,0 +1,20 @@
+#ifndef IMAGE_H
+#define IMAGE_H
+
+#if defined(USE_LIBPNG)
+#include <png.h>
+#elif defined(USE_LODEPNG)
+#include "lodepng.h"
+#else
+#error "No png implementation"
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+
+// API structured after lodepng API
+
+unsigned decode32(uint32_t** out, unsigned* w, unsigned* h, unsigned char* in, size_t insize);
+unsigned encode32_file(const char* filename, const uint32_t* image, unsigned w, unsigned h);
+
+#endif \ No newline at end of file
diff --git a/src/main.c b/src/main.c
index e332fb1..5d3291f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,20 +3,10 @@
#include <stdint.h>
#include <string.h>
+#include "common.h"
+#include "embed.h"
#include "get_image_for_rom.h"
-#include "png/lodepng.h"
-
-extern const uint8_t cgb_boot_bin[];
-extern const size_t cgb_boot_bin_size;
-
-extern unsigned char CartridgeTemplate_png[];
-extern unsigned int CartridgeTemplate_png_size;
-
-extern unsigned char ColorCartridgeTemplate_png[];
-extern unsigned int ColorCartridgeTemplate_png_size;
-
-extern unsigned char UniversalCartridgeTemplate_png[];
-extern unsigned int UniversalCartridgeTemplate_png_size;
+#include "image.h"
static uint32_t alpha_blend(const uint32_t dest, const uint32_t src)
{
@@ -95,16 +85,6 @@ static void scale_image(const uint32_t* input, const signed input_width, const s
}
}
-static void* local_malloc(size_t size)
-{
- void* mem = malloc(size);
- if (!mem) {
- fprintf(stderr, "Failed to allocate memory\n");
- exit(-1);
- }
- return mem;
-}
-
int main (int argc , char** argv)
{
#define str(x) #x
@@ -121,7 +101,7 @@ int main (int argc , char** argv)
const uint16_t X_OFFSET = 192;
const uint16_t Y_OFFSET = 298;
- unsigned int size = 128;
+ int size = 128;
char* input = NULL;
char* output = NULL;
@@ -191,12 +171,11 @@ int main (int argc , char** argv)
template_size = CartridgeTemplate_png_size;
}
- if (lodepng_decode32((unsigned char**)&template, &template_width, &template_height, template_data, template_size)) {
+ if (decode32(&template, &template_width, &template_height, template_data, template_size)) {
fprintf(stderr, "Failed to decode template\n");
return -1;
}
-
uint32_t* canvas = local_malloc(template_width * template_height * sizeof(uint32_t));
// clear the canvas so we don't end up with garbage data somewhere
memset(canvas, 0, template_width * template_height * sizeof(uint32_t));
@@ -224,7 +203,7 @@ int main (int argc , char** argv)
uint32_t* final = local_malloc(size * size * sizeof(uint32_t));
scale_image(canvas, template_width, template_height, final, (double)size/template_width, template_width/size);
- lodepng_encode32_file(output, (const unsigned char*)final, size, size);
+ encode32_file(output, final, size, size);
free(final);
free(canvas);
diff --git a/src/png/CMakeLists.txt b/src/png/CMakeLists.txt
deleted file mode 100644
index 056e096..0000000
--- a/src/png/CMakeLists.txt
+++ /dev/null
@@ -1,8 +0,0 @@
-
-list(APPEND
- LODEPNG_SOURCES
- ${CMAKE_CURRENT_SOURCE_DIR}/lodepng.c
- ${CMAKE_CURRENT_SOURCE_DIR}/lodepng.h
-)
-
-add_library(lodepng STATIC ${LODEPNG_SOURCES}) \ No newline at end of file
diff --git a/src/png/LICENSE b/src/png/LICENSE
deleted file mode 100644
index a5fb060..0000000
--- a/src/png/LICENSE
+++ /dev/null
@@ -1,21 +0,0 @@
-Copyright (c) 2005-2018 Lode Vandevenne
-
-This software is provided 'as-is', without any express or implied
-warranty. In no event will the authors be held liable for any damages
-arising from the use of this software.
-
-Permission is granted to anyone to use this software for any purpose,
-including commercial applications, and to alter it and redistribute it
-freely, subject to the following restrictions:
-
- 1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
-
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
-
- 3. This notice may not be removed or altered from any source
- distribution.
-
diff --git a/src/png/lodepng.c b/src/png/lodepng.c
deleted file mode 100644
index 51492b8..0000000
--- a/src/png/lodepng.c
+++ /dev/null
@@ -1,6464 +0,0 @@
-/*
-LodePNG version 20201017
-
-Copyright (c) 2005-2020 Lode Vandevenne
-
-This software is provided 'as-is', without any express or implied
-warranty. In no event will the authors be held liable for any damages
-arising from the use of this software.
-
-Permission is granted to anyone to use this software for any purpose,
-including commercial applications, and to alter it and redistribute it
-freely, subject to the following restrictions:
-
- 1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
-
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
-
- 3. This notice may not be removed or altered from any source
- distribution.
-*/
-
-/*
-The manual and changelog are in the header file "lodepng.h"
-Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C.
-*/
-
-#include "lodepng.h"
-
-#ifdef LODEPNG_COMPILE_DISK
-#include <limits.h> /* LONG_MAX */
-#include <stdio.h> /* file handling */
-#endif /* LODEPNG_COMPILE_DISK */
-
-#ifdef LODEPNG_COMPILE_ALLOCATORS
-#include <stdlib.h> /* allocations */
-#endif /* LODEPNG_COMPILE_ALLOCATORS */
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/
-#pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/
-#pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
-#endif /*_MSC_VER */
-
-const char* LODEPNG_VERSION_STRING = "20201017";
-
-/*
-This source file is built up in the following large parts. The code sections
-with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way.
--Tools for C and common code for PNG and Zlib
--C Code for Zlib (huffman, deflate, ...)
--C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...)
--The C++ wrapper around all of the above
-*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* // Tools for C, and common code for PNG and Zlib. // */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*The malloc, realloc and free functions defined here with "lodepng_" in front
-of the name, so that you can easily change them to others related to your
-platform if needed. Everything else in the code calls these. Pass
--DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out
-#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and
-define them in your own project's source files without needing to change
-lodepng source code. Don't forget to remove "static" if you copypaste them
-from here.*/
-
-#ifdef LODEPNG_COMPILE_ALLOCATORS
-static void* lodepng_malloc(size_t size) {
-#ifdef LODEPNG_MAX_ALLOC
- if(size > LODEPNG_MAX_ALLOC) return 0;
-#endif
- return malloc(size);
-}
-
-/* NOTE: when realloc returns NULL, it leaves the original memory untouched */
-static void* lodepng_realloc(void* ptr, size_t new_size) {
-#ifdef LODEPNG_MAX_ALLOC
- if(new_size > LODEPNG_MAX_ALLOC) return 0;
-#endif
- return realloc(ptr, new_size);
-}
-
-static void lodepng_free(void* ptr) {
- free(ptr);
-}
-#else /*LODEPNG_COMPILE_ALLOCATORS*/
-/* TODO: support giving additional void* payload to the custom allocators */
-void* lodepng_malloc(size_t size);
-void* lodepng_realloc(void* ptr, size_t new_size);
-void lodepng_free(void* ptr);
-#endif /*LODEPNG_COMPILE_ALLOCATORS*/
-
-/* convince the compiler to inline a function, for use when this measurably improves performance */
-/* inline is not available in C90, but use it when supported by the compiler */
-#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L))
-#define LODEPNG_INLINE inline
-#else
-#define LODEPNG_INLINE /* not available */
-#endif
-
-/* restrict is not available in C90, but use it when supported by the compiler */
-#if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\
- (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \
- (defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus))
-#define LODEPNG_RESTRICT __restrict
-#else
-#define LODEPNG_RESTRICT /* not available */
-#endif
-
-/* Replacements for C library functions such as memcpy and strlen, to support platforms
-where a full C library is not available. The compiler can recognize them and compile
-to something as fast. */
-
-static void lodepng_memcpy(void* LODEPNG_RESTRICT dst,
- const void* LODEPNG_RESTRICT src, size_t size) {
- size_t i;
- for(i = 0; i < size; i++) ((char*)dst)[i] = ((const char*)src)[i];
-}
-
-static void lodepng_memset(void* LODEPNG_RESTRICT dst,
- int value, size_t num) {
- size_t i;
- for(i = 0; i < num; i++) ((char*)dst)[i] = (char)value;
-}
-
-/* does not check memory out of bounds, do not use on untrusted data */
-static size_t lodepng_strlen(const char* a) {
- const char* orig = a;
- /* avoid warning about unused function in case of disabled COMPILE... macros */
- (void)(&lodepng_strlen);
- while(*a) a++;
- return (size_t)(a - orig);
-}
-
-#define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b))
-#define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b))
-#define LODEPNG_ABS(x) ((x) < 0 ? -(x) : (x))
-
-#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)
-/* Safely check if adding two integers will overflow (no undefined
-behavior, compiler removing the code, etc...) and output result. */
-static int lodepng_addofl(size_t a, size_t b, size_t* result) {
- *result = a + b; /* Unsigned addition is well defined and safe in C90 */
- return *result < a;
-}
-#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-/* Safely check if multiplying two integers will overflow (no undefined
-behavior, compiler removing the code, etc...) and output result. */
-static int lodepng_mulofl(size_t a, size_t b, size_t* result) {
- *result = a * b; /* Unsigned multiplication is well defined and safe in C90 */
- return (a != 0 && *result / a != b);
-}
-
-#ifdef LODEPNG_COMPILE_ZLIB
-/* Safely check if a + b > c, even if overflow could happen. */
-static int lodepng_gtofl(size_t a, size_t b, size_t c) {
- size_t d;
- if(lodepng_addofl(a, b, &d)) return 1;
- return d > c;
-}
-#endif /*LODEPNG_COMPILE_ZLIB*/
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-
-/*
-Often in case of an error a value is assigned to a variable and then it breaks
-out of a loop (to go to the cleanup phase of a function). This macro does that.
-It makes the error handling code shorter and more readable.
-
-Example: if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83);
-*/
-#define CERROR_BREAK(errorvar, code){\
- errorvar = code;\
- break;\
-}
-
-/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/
-#define ERROR_BREAK(code) CERROR_BREAK(error, code)
-
-/*Set error var to the error code, and return it.*/
-#define CERROR_RETURN_ERROR(errorvar, code){\
- errorvar = code;\
- return code;\
-}
-
-/*Try the code, if it returns error, also return the error.*/
-#define CERROR_TRY_RETURN(call){\
- unsigned error = call;\
- if(error) return error;\
-}
-
-/*Set error var to the error code, and return from the void function.*/
-#define CERROR_RETURN(errorvar, code){\
- errorvar = code;\
- return;\
-}
-
-/*
-About uivector, ucvector and string:
--All of them wrap dynamic arrays or text strings in a similar way.
--LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version.
--The string tools are made to avoid problems with compilers that declare things like strncat as deprecated.
--They're not used in the interface, only internally in this file as static functions.
--As with many other structs in this file, the init and cleanup functions serve as ctor and dtor.
-*/
-
-#ifdef LODEPNG_COMPILE_ZLIB
-#ifdef LODEPNG_COMPILE_ENCODER
-/*dynamic vector of unsigned ints*/
-typedef struct uivector {
- unsigned* data;
- size_t size; /*size in number of unsigned longs*/
- size_t allocsize; /*allocated size in bytes*/
-} uivector;
-
-static void uivector_cleanup(void* p) {
- ((uivector*)p)->size = ((uivector*)p)->allocsize = 0;
- lodepng_free(((uivector*)p)->data);
- ((uivector*)p)->data = NULL;
-}
-
-/*returns 1 if success, 0 if failure ==> nothing done*/
-static unsigned uivector_resize(uivector* p, size_t size) {
- size_t allocsize = size * sizeof(unsigned);
- if(allocsize > p->allocsize) {
- size_t newsize = allocsize + (p->allocsize >> 1u);
- void* data = lodepng_realloc(p->data, newsize);
- if(data) {
- p->allocsize = newsize;
- p->data = (unsigned*)data;
- }
- else return 0; /*error: not enough memory*/
- }
- p->size = size;
- return 1; /*success*/
-}
-
-static void uivector_init(uivector* p) {
- p->data = NULL;
- p->size = p->allocsize = 0;
-}
-
-/*returns 1 if success, 0 if failure ==> nothing done*/
-static unsigned uivector_push_back(uivector* p, unsigned c) {
- if(!uivector_resize(p, p->size + 1)) return 0;
- p->data[p->size - 1] = c;
- return 1;
-}
-#endif /*LODEPNG_COMPILE_ENCODER*/
-#endif /*LODEPNG_COMPILE_ZLIB*/
-
-/* /////////////////////////////////////////////////////////////////////////// */
-
-/*dynamic vector of unsigned chars*/
-typedef struct ucvector {
- unsigned char* data;
- size_t size; /*used size*/
- size_t allocsize; /*allocated size*/
-} ucvector;
-
-/*returns 1 if success, 0 if failure ==> nothing done*/
-static unsigned ucvector_resize(ucvector* p, size_t size) {
- if(size > p->allocsize) {
- size_t newsize = size + (p->allocsize >> 1u);
- void* data = lodepng_realloc(p->data, newsize);
- if(data) {
- p->allocsize = newsize;
- p->data = (unsigned char*)data;
- }
- else return 0; /*error: not enough memory*/
- }
- p->size = size;
- return 1; /*success*/
-}
-
-static ucvector ucvector_init(unsigned char* buffer, size_t size) {
- ucvector v;
- v.data = buffer;
- v.allocsize = v.size = size;
- return v;
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_PNG
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-
-/*free string pointer and set it to NULL*/
-static void string_cleanup(char** out) {
- lodepng_free(*out);
- *out = NULL;
-}
-
-/*also appends null termination character*/
-static char* alloc_string_sized(const char* in, size_t insize) {
- char* out = (char*)lodepng_malloc(insize + 1);
- if(out) {
- lodepng_memcpy(out, in, insize);
- out[insize] = 0;
- }
- return out;
-}
-
-/* dynamically allocates a new string with a copy of the null terminated input text */
-static char* alloc_string(const char* in) {
- return alloc_string_sized(in, lodepng_strlen(in));
-}
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-#endif /*LODEPNG_COMPILE_PNG*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)
-static unsigned lodepng_read32bitInt(const unsigned char* buffer) {
- return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) |
- ((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]);
-}
-#endif /*defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)*/
-
-#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)
-/*buffer must have at least 4 allocated bytes available*/
-static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) {
- buffer[0] = (unsigned char)((value >> 24) & 0xff);
- buffer[1] = (unsigned char)((value >> 16) & 0xff);
- buffer[2] = (unsigned char)((value >> 8) & 0xff);
- buffer[3] = (unsigned char)((value ) & 0xff);
-}
-#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / File IO / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_DISK
-
-/* returns negative value on error. This should be pure C compatible, so no fstat. */
-static long lodepng_filesize(const char* filename) {
- FILE* file;
- long size;
- file = fopen(filename, "rb");
- if(!file) return -1;
-
- if(fseek(file, 0, SEEK_END) != 0) {
- fclose(file);
- return -1;
- }
-
- size = ftell(file);
- /* It may give LONG_MAX as directory size, this is invalid for us. */
- if(size == LONG_MAX) size = -1;
-
- fclose(file);
- return size;
-}
-
-/* load file into buffer that already has the correct allocated size. Returns error code.*/
-static unsigned lodepng_buffer_file(unsigned char* out, size_t size, const char* filename) {
- FILE* file;
- size_t readsize;
- file = fopen(filename, "rb");
- if(!file) return 78;
-
- readsize = fread(out, 1, size, file);
- fclose(file);
-
- if(readsize != size) return 78;
- return 0;
-}
-
-unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) {
- long size = lodepng_filesize(filename);
- if(size < 0) return 78;
- *outsize = (size_t)size;
-
- *out = (unsigned char*)lodepng_malloc((size_t)size);
- if(!(*out) && size > 0) return 83; /*the above malloc failed*/
-
- return lodepng_buffer_file(*out, (size_t)size, filename);
-}
-
-/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
-unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) {
- FILE* file;
- file = fopen(filename, "wb" );
- if(!file) return 79;
- fwrite(buffer, 1, buffersize, file);
- fclose(file);
- return 0;
-}
-
-#endif /*LODEPNG_COMPILE_DISK*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* // End of common code and tools. Begin of Zlib related code. // */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_ZLIB
-#ifdef LODEPNG_COMPILE_ENCODER
-
-typedef struct {
- ucvector* data;
- unsigned char bp; /*ok to overflow, indicates bit pos inside byte*/
-} LodePNGBitWriter;
-
-static void LodePNGBitWriter_init(LodePNGBitWriter* writer, ucvector* data) {
- writer->data = data;
- writer->bp = 0;
-}
-
-/*TODO: this ignores potential out of memory errors*/
-#define WRITEBIT(writer, bit){\
- /* append new byte */\
- if(((writer->bp) & 7u) == 0) {\
- if(!ucvector_resize(writer->data, writer->data->size + 1)) return;\
- writer->data->data[writer->data->size - 1] = 0;\
- }\
- (writer->data->data[writer->data->size - 1]) |= (bit << ((writer->bp) & 7u));\
- ++writer->bp;\
-}
-
-/* LSB of value is written first, and LSB of bytes is used first */
-static void writeBits(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
- if(nbits == 1) { /* compiler should statically compile this case if nbits == 1 */
- WRITEBIT(writer, value);
- } else {
- /* TODO: increase output size only once here rather than in each WRITEBIT */
- size_t i;
- for(i = 0; i != nbits; ++i) {
- WRITEBIT(writer, (unsigned char)((value >> i) & 1));
- }
- }
-}
-
-/* This one is to use for adding huffman symbol, the value bits are written MSB first */
-static void writeBitsReversed(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
- size_t i;
- for(i = 0; i != nbits; ++i) {
- /* TODO: increase output size only once here rather than in each WRITEBIT */
- WRITEBIT(writer, (unsigned char)((value >> (nbits - 1u - i)) & 1u));
- }
-}
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-typedef struct {
- const unsigned char* data;
- size_t size; /*size of data in bytes*/
- size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/
- size_t bp;
- unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/
-} LodePNGBitReader;
-
-/* data size argument is in bytes. Returns error if size too large causing overflow */
-static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, const unsigned char* data, size_t size) {
- size_t temp;
- reader->data = data;
- reader->size = size;
- /* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB) */
- if(lodepng_mulofl(size, 8u, &reader->bitsize)) return 105;
- /*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and
- trying to ensure 32 more bits*/
- if(lodepng_addofl(reader->bitsize, 64u, &temp)) return 105;
- reader->bp = 0;
- reader->buffer = 0;
- return 0; /*ok*/
-}
-
-/*
-ensureBits functions:
-Ensures the reader can at least read nbits bits in one or more readBits calls,
-safely even if not enough bits are available.
-Returns 1 if there are enough bits available, 0 if not.
-*/
-
-/*See ensureBits documentation above. This one ensures exactly 1 bit */
-/*static unsigned ensureBits1(LodePNGBitReader* reader) {
- if(reader->bp >= reader->bitsize) return 0;
- reader->buffer = (unsigned)reader->data[reader->bp >> 3u] >> (reader->bp & 7u);
- return 1;
-}*/
-
-/*See ensureBits documentation above. This one ensures up to 9 bits */
-static unsigned ensureBits9(LodePNGBitReader* reader, size_t nbits) {
- size_t start = reader->bp >> 3u;
- size_t size = reader->size;
- if(start + 1u < size) {
- reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u);
- reader->buffer >>= (reader->bp & 7u);
- return 1;
- } else {
- reader->buffer = 0;
- if(start + 0u < size) reader->buffer |= reader->data[start + 0];
- reader->buffer >>= (reader->bp & 7u);
- return reader->bp + nbits <= reader->bitsize;
- }
-}
-
-/*See ensureBits documentation above. This one ensures up to 17 bits */
-static unsigned ensureBits17(LodePNGBitReader* reader, size_t nbits) {
- size_t start = reader->bp >> 3u;
- size_t size = reader->size;
- if(start + 2u < size) {
- reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
- ((unsigned)reader->data[start + 2] << 16u);
- reader->buffer >>= (reader->bp & 7u);
- return 1;
- } else {
- reader->buffer = 0;
- if(start + 0u < size) reader->buffer |= reader->data[start + 0];
- if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
- reader->buffer >>= (reader->bp & 7u);
- return reader->bp + nbits <= reader->bitsize;
- }
-}
-
-/*See ensureBits documentation above. This one ensures up to 25 bits */
-static LODEPNG_INLINE unsigned ensureBits25(LodePNGBitReader* reader, size_t nbits) {
- size_t start = reader->bp >> 3u;
- size_t size = reader->size;
- if(start + 3u < size) {
- reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
- ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u);
- reader->buffer >>= (reader->bp & 7u);
- return 1;
- } else {
- reader->buffer = 0;
- if(start + 0u < size) reader->buffer |= reader->data[start + 0];
- if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
- if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u);
- reader->buffer >>= (reader->bp & 7u);
- return reader->bp + nbits <= reader->bitsize;
- }
-}
-
-/*See ensureBits documentation above. This one ensures up to 32 bits */
-static LODEPNG_INLINE unsigned ensureBits32(LodePNGBitReader* reader, size_t nbits) {
- size_t start = reader->bp >> 3u;
- size_t size = reader->size;
- if(start + 4u < size) {
- reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) |
- ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u);
- reader->buffer >>= (reader->bp & 7u);
- reader->buffer |= (((unsigned)reader->data[start + 4] << 24u) << (8u - (reader->bp & 7u)));
- return 1;
- } else {
- reader->buffer = 0;
- if(start + 0u < size) reader->buffer |= reader->data[start + 0];
- if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u);
- if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u);
- if(start + 3u < size) reader->buffer |= ((unsigned)reader->data[start + 3] << 24u);
- reader->buffer >>= (reader->bp & 7u);
- return reader->bp + nbits <= reader->bitsize;
- }
-}
-
-/* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */
-static unsigned peekBits(LodePNGBitReader* reader, size_t nbits) {
- /* The shift allows nbits to be only up to 31. */
- return reader->buffer & ((1u << nbits) - 1u);
-}
-
-/* Must have enough bits available with ensureBits */
-static void advanceBits(LodePNGBitReader* reader, size_t nbits) {
- reader->buffer >>= nbits;
- reader->bp += nbits;
-}
-
-/* Must have enough bits available with ensureBits */
-static unsigned readBits(LodePNGBitReader* reader, size_t nbits) {
- unsigned result = peekBits(reader, nbits);
- advanceBits(reader, nbits);
- return result;
-}
-
-/* Public for testing only. steps and result must have numsteps values. */
-unsigned lode_png_test_bitreader(const unsigned char* data, size_t size,
- size_t numsteps, const size_t* steps, unsigned* result) {
- size_t i;
- LodePNGBitReader reader;
- unsigned error = LodePNGBitReader_init(&reader, data, size);
- if(error) return 0;
- for(i = 0; i < numsteps; i++) {
- size_t step = steps[i];
- unsigned ok;
- if(step > 25) ok = ensureBits32(&reader, step);
- else if(step > 17) ok = ensureBits25(&reader, step);
- else if(step > 9) ok = ensureBits17(&reader, step);
- else ok = ensureBits9(&reader, step);
- if(!ok) return 0;
- result[i] = readBits(&reader, step);
- }
- return 1;
-}
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-static unsigned reverseBits(unsigned bits, unsigned num) {
- /*TODO: implement faster lookup table based version when needed*/
- unsigned i, result = 0;
- for(i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i;
- return result;
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Deflate - Huffman / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#define FIRST_LENGTH_CODE_INDEX 257
-#define LAST_LENGTH_CODE_INDEX 285
-/*256 literals, the end code, some length codes, and 2 unused codes*/
-#define NUM_DEFLATE_CODE_SYMBOLS 288
-/*the distance codes have their own symbols, 30 used, 2 unused*/
-#define NUM_DISTANCE_SYMBOLS 32
-/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/
-#define NUM_CODE_LENGTH_CODES 19
-
-/*the base lengths represented by codes 257-285*/
-static const unsigned LENGTHBASE[29]
- = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
- 67, 83, 99, 115, 131, 163, 195, 227, 258};
-
-/*the extra bits used by codes 257-285 (added to base length)*/
-static const unsigned LENGTHEXTRA[29]
- = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3,
- 4, 4, 4, 4, 5, 5, 5, 5, 0};
-
-/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/
-static const unsigned DISTANCEBASE[30]
- = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
- 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
-
-/*the extra bits of backwards distances (added to base)*/
-static const unsigned DISTANCEEXTRA[30]
- = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8,
- 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
-
-/*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman
-tree of the dynamic huffman tree lengths is generated*/
-static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES]
- = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*
-Huffman tree struct, containing multiple representations of the tree
-*/
-typedef struct HuffmanTree {
- unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/
- unsigned* lengths; /*the lengths of the huffman codes*/
- unsigned maxbitlen; /*maximum number of bits a single code can get*/
- unsigned numcodes; /*number of symbols in the alphabet = number of codes*/
- /* for reading only */
- unsigned char* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/
- unsigned short* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/
-} HuffmanTree;
-
-static void HuffmanTree_init(HuffmanTree* tree) {
- tree->codes = 0;
- tree->lengths = 0;
- tree->table_len = 0;
- tree->table_value = 0;
-}
-
-static void HuffmanTree_cleanup(HuffmanTree* tree) {
- lodepng_free(tree->codes);
- lodepng_free(tree->lengths);
- lodepng_free(tree->table_len);
- lodepng_free(tree->table_value);
-}
-
-/* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/
-/* values 8u and 9u work the fastest */
-#define FIRSTBITS 9u
-
-/* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination,
-which is possible in case of only 0 or 1 present symbols. */
-#define INVALIDSYMBOL 65535u
-
-/* make table for huffman decoding */
-static unsigned HuffmanTree_makeTable(HuffmanTree* tree) {
- static const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/
- static const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u;
- size_t i, numpresent, pointer, size; /*total table size*/
- unsigned* maxlens = (unsigned*)lodepng_malloc(headsize * sizeof(unsigned));
- if(!maxlens) return 83; /*alloc fail*/
-
- /* compute maxlens: max total bit length of symbols sharing prefix in the first table*/
- lodepng_memset(maxlens, 0, headsize * sizeof(*maxlens));
- for(i = 0; i < tree->numcodes; i++) {
- unsigned symbol = tree->codes[i];
- unsigned l = tree->lengths[i];
- unsigned index;
- if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/
- /*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/
- index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS);
- maxlens[index] = LODEPNG_MAX(maxlens[index], l);
- }
- /* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */
- size = headsize;
- for(i = 0; i < headsize; ++i) {
- unsigned l = maxlens[i];
- if(l > FIRSTBITS) size += (1u << (l - FIRSTBITS));
- }
- tree->table_len = (unsigned char*)lodepng_malloc(size * sizeof(*tree->table_len));
- tree->table_value = (unsigned short*)lodepng_malloc(size * sizeof(*tree->table_value));
- if(!tree->table_len || !tree->table_value) {
- lodepng_free(maxlens);
- /* freeing tree->table values is done at a higher scope */
- return 83; /*alloc fail*/
- }
- /*initialize with an invalid length to indicate unused entries*/
- for(i = 0; i < size; ++i) tree->table_len[i] = 16;
-
- /*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/
- pointer = headsize;
- for(i = 0; i < headsize; ++i) {
- unsigned l = maxlens[i];
- if(l <= FIRSTBITS) continue;
- tree->table_len[i] = l;
- tree->table_value[i] = pointer;
- pointer += (1u << (l - FIRSTBITS));
- }
- lodepng_free(maxlens);
-
- /*fill in the first table for short symbols, or secondary table for long symbols*/
- numpresent = 0;
- for(i = 0; i < tree->numcodes; ++i) {
- unsigned l = tree->lengths[i];
- unsigned symbol = tree->codes[i]; /*the huffman bit pattern. i itself is the value.*/
- /*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/
- unsigned reverse = reverseBits(symbol, l);
- if(l == 0) continue;
- numpresent++;
-
- if(l <= FIRSTBITS) {
- /*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/
- unsigned num = 1u << (FIRSTBITS - l);
- unsigned j;
- for(j = 0; j < num; ++j) {
- /*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/
- unsigned index = reverse | (j << l);
- if(tree->table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
- tree->table_len[index] = l;
- tree->table_value[index] = i;
- }
- } else {
- /*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/
- /*the FIRSTBITS MSBs of the symbol are the first table index*/
- unsigned index = reverse & mask;
- unsigned maxlen = tree->table_len[index];
- /*log2 of secondary table length, should be >= l - FIRSTBITS*/
- unsigned tablelen = maxlen - FIRSTBITS;
- unsigned start = tree->table_value[index]; /*starting index in secondary table*/
- unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/
- unsigned j;
- if(maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
- for(j = 0; j < num; ++j) {
- unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */
- unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS)));
- tree->table_len[index2] = l;
- tree->table_value[index2] = i;
- }
- }
- }
-
- if(numpresent < 2) {
- /* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits,
- but deflate uses 1 bit instead. In case of 0 symbols, no symbols can
- appear at all, but such huffman tree could still exist (e.g. if distance
- codes are never used). In both cases, not all symbols of the table will be
- filled in. Fill them in with an invalid symbol value so returning them from
- huffmanDecodeSymbol will cause error. */
- for(i = 0; i < size; ++i) {
- if(tree->table_len[i] == 16) {
- /* As length, use a value smaller than FIRSTBITS for the head table,
- and a value larger than FIRSTBITS for the secondary table, to ensure
- valid behavior for advanceBits when reading this symbol. */
- tree->table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1);
- tree->table_value[i] = INVALIDSYMBOL;
- }
- }
- } else {
- /* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes.
- If that is not the case (due to too long length codes), the table will not
- have been fully used, and this is an error (not all bit combinations can be
- decoded): an oversubscribed huffman tree, indicated by error 55. */
- for(i = 0; i < size; ++i) {
- if(tree->table_len[i] == 16) return 55;
- }
- }
-
- return 0;
-}
-
-/*
-Second step for the ...makeFromLengths and ...makeFromFrequencies functions.
-numcodes, lengths and maxbitlen must already be filled in correctly. return
-value is error.
-*/
-static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) {
- unsigned* blcount;
- unsigned* nextcode;
- unsigned error = 0;
- unsigned bits, n;
-
- tree->codes = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned));
- blcount = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned));
- nextcode = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned));
- if(!tree->codes || !blcount || !nextcode) error = 83; /*alloc fail*/
-
- if(!error) {
- for(n = 0; n != tree->maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0;
- /*step 1: count number of instances of each code length*/
- for(bits = 0; bits != tree->numcodes; ++bits) ++blcount[tree->lengths[bits]];
- /*step 2: generate the nextcode values*/
- for(bits = 1; bits <= tree->maxbitlen; ++bits) {
- nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u;
- }
- /*step 3: generate all the codes*/
- for(n = 0; n != tree->numcodes; ++n) {
- if(tree->lengths[n] != 0) {
- tree->codes[n] = nextcode[tree->lengths[n]]++;
- /*remove superfluous bits from the code*/
- tree->codes[n] &= ((1u << tree->lengths[n]) - 1u);
- }
- }
- }
-
- lodepng_free(blcount);
- lodepng_free(nextcode);
-
- if(!error) error = HuffmanTree_makeTable(tree);
- return error;
-}
-
-/*
-given the code lengths (as stored in the PNG file), generate the tree as defined
-by Deflate. maxbitlen is the maximum bits that a code in the tree can have.
-return value is error.
-*/
-static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen,
- size_t numcodes, unsigned maxbitlen) {
- unsigned i;
- tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
- if(!tree->lengths) return 83; /*alloc fail*/
- for(i = 0; i != numcodes; ++i) tree->lengths[i] = bitlen[i];
- tree->numcodes = (unsigned)numcodes; /*number of symbols*/
- tree->maxbitlen = maxbitlen;
- return HuffmanTree_makeFromLengths2(tree);
-}
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-/*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding",
-Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/
-
-/*chain node for boundary package merge*/
-typedef struct BPMNode {
- int weight; /*the sum of all weights in this chain*/
- unsigned index; /*index of this leaf node (called "count" in the paper)*/
- struct BPMNode* tail; /*the next nodes in this chain (null if last)*/
- int in_use;
-} BPMNode;
-
-/*lists of chains*/
-typedef struct BPMLists {
- /*memory pool*/
- unsigned memsize;
- BPMNode* memory;
- unsigned numfree;
- unsigned nextfree;
- BPMNode** freelist;
- /*two heads of lookahead chains per list*/
- unsigned listsize;
- BPMNode** chains0;
- BPMNode** chains1;
-} BPMLists;
-
-/*creates a new chain node with the given parameters, from the memory in the lists */
-static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) {
- unsigned i;
- BPMNode* result;
-
- /*memory full, so garbage collect*/
- if(lists->nextfree >= lists->numfree) {
- /*mark only those that are in use*/
- for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0;
- for(i = 0; i != lists->listsize; ++i) {
- BPMNode* node;
- for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1;
- for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1;
- }
- /*collect those that are free*/
- lists->numfree = 0;
- for(i = 0; i != lists->memsize; ++i) {
- if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i];
- }
- lists->nextfree = 0;
- }
-
- result = lists->freelist[lists->nextfree++];
- result->weight = weight;
- result->index = index;
- result->tail = tail;
- return result;
-}
-
-/*sort the leaves with stable mergesort*/
-static void bpmnode_sort(BPMNode* leaves, size_t num) {
- BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num);
- size_t width, counter = 0;
- for(width = 1; width < num; width *= 2) {
- BPMNode* a = (counter & 1) ? mem : leaves;
- BPMNode* b = (counter & 1) ? leaves : mem;
- size_t p;
- for(p = 0; p < num; p += 2 * width) {
- size_t q = (p + width > num) ? num : (p + width);
- size_t r = (p + 2 * width > num) ? num : (p + 2 * width);
- size_t i = p, j = q, k;
- for(k = p; k < r; k++) {
- if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++];
- else b[k] = a[j++];
- }
- }
- counter++;
- }
- if(counter & 1) lodepng_memcpy(leaves, mem, sizeof(*leaves) * num);
- lodepng_free(mem);
-}
-
-/*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/
-static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) {
- unsigned lastindex = lists->chains1[c]->index;
-
- if(c == 0) {
- if(lastindex >= numpresent) return;
- lists->chains0[c] = lists->chains1[c];
- lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0);
- } else {
- /*sum of the weights of the head nodes of the previous lookahead chains.*/
- int sum = lists->chains0[c - 1]->weight + lists->chains1[c - 1]->weight;
- lists->chains0[c] = lists->chains1[c];
- if(lastindex < numpresent && sum > leaves[lastindex].weight) {
- lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists->chains1[c]->tail);
- return;
- }
- lists->chains1[c] = bpmnode_create(lists, sum, lastindex, lists->chains1[c - 1]);
- /*in the end we are only interested in the chain of the last list, so no
- need to recurse if we're at the last one (this gives measurable speedup)*/
- if(num + 1 < (int)(2 * numpresent - 2)) {
- boundaryPM(lists, leaves, numpresent, c - 1, num);
- boundaryPM(lists, leaves, numpresent, c - 1, num);
- }
- }
-}
-
-unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
- size_t numcodes, unsigned maxbitlen) {
- unsigned error = 0;
- unsigned i;
- size_t numpresent = 0; /*number of symbols with non-zero frequency*/
- BPMNode* leaves; /*the symbols, only those with > 0 frequency*/
-
- if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/
- if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/
-
- leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves));
- if(!leaves) return 83; /*alloc fail*/
-
- for(i = 0; i != numcodes; ++i) {
- if(frequencies[i] > 0) {
- leaves[numpresent].weight = (int)frequencies[i];
- leaves[numpresent].index = i;
- ++numpresent;
- }
- }
-
- lodepng_memset(lengths, 0, numcodes * sizeof(*lengths));
-
- /*ensure at least two present symbols. There should be at least one symbol
- according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To
- make these work as well ensure there are at least two symbols. The
- Package-Merge code below also doesn't work correctly if there's only one
- symbol, it'd give it the theoretical 0 bits but in practice zlib wants 1 bit*/
- if(numpresent == 0) {
- lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/
- } else if(numpresent == 1) {
- lengths[leaves[0].index] = 1;
- lengths[leaves[0].index == 0 ? 1 : 0] = 1;
- } else {
- BPMLists lists;
- BPMNode* node;
-
- bpmnode_sort(leaves, numpresent);
-
- lists.listsize = maxbitlen;
- lists.memsize = 2 * maxbitlen * (maxbitlen + 1);
- lists.nextfree = 0;
- lists.numfree = lists.memsize;
- lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory));
- lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*));
- lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
- lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
- if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/
-
- if(!error) {
- for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i];
-
- bpmnode_create(&lists, leaves[0].weight, 1, 0);
- bpmnode_create(&lists, leaves[1].weight, 2, 0);
-
- for(i = 0; i != lists.listsize; ++i) {
- lists.chains0[i] = &lists.memory[0];
- lists.chains1[i] = &lists.memory[1];
- }
-
- /*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/
- for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i);
-
- for(node = lists.chains1[maxbitlen - 1]; node; node = node->tail) {
- for(i = 0; i != node->index; ++i) ++lengths[leaves[i].index];
- }
- }
-
- lodepng_free(lists.memory);
- lodepng_free(lists.freelist);
- lodepng_free(lists.chains0);
- lodepng_free(lists.chains1);
- }
-
- lodepng_free(leaves);
- return error;
-}
-
-/*Create the Huffman tree given the symbol frequencies*/
-static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies,
- size_t mincodes, size_t numcodes, unsigned maxbitlen) {
- unsigned error = 0;
- while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/
- tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
- if(!tree->lengths) return 83; /*alloc fail*/
- tree->maxbitlen = maxbitlen;
- tree->numcodes = (unsigned)numcodes; /*number of symbols*/
-
- error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen);
- if(!error) error = HuffmanTree_makeFromLengths2(tree);
- return error;
-}
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/
-static unsigned generateFixedLitLenTree(HuffmanTree* tree) {
- unsigned i, error = 0;
- unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
- if(!bitlen) return 83; /*alloc fail*/
-
- /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/
- for(i = 0; i <= 143; ++i) bitlen[i] = 8;
- for(i = 144; i <= 255; ++i) bitlen[i] = 9;
- for(i = 256; i <= 279; ++i) bitlen[i] = 7;
- for(i = 280; i <= 287; ++i) bitlen[i] = 8;
-
- error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15);
-
- lodepng_free(bitlen);
- return error;
-}
-
-/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/
-static unsigned generateFixedDistanceTree(HuffmanTree* tree) {
- unsigned i, error = 0;
- unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
- if(!bitlen) return 83; /*alloc fail*/
-
- /*there are 32 distance codes, but 30-31 are unused*/
- for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5;
- error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15);
-
- lodepng_free(bitlen);
- return error;
-}
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-/*
-returns the code. The bit reader must already have been ensured at least 15 bits
-*/
-static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, const HuffmanTree* codetree) {
- unsigned short code = peekBits(reader, FIRSTBITS);
- unsigned short l = codetree->table_len[code];
- unsigned short value = codetree->table_value[code];
- if(l <= FIRSTBITS) {
- advanceBits(reader, l);
- return value;
- } else {
- unsigned index2;
- advanceBits(reader, FIRSTBITS);
- index2 = value + peekBits(reader, l - FIRSTBITS);
- advanceBits(reader, codetree->table_len[index2] - FIRSTBITS);
- return codetree->table_value[index2];
- }
-}
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Inflator (Decompressor) / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*get the tree of a deflated block with fixed tree, as specified in the deflate specification
-Returns error code.*/
-static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) {
- unsigned error = generateFixedLitLenTree(tree_ll);
- if(error) return error;
- return generateFixedDistanceTree(tree_d);
-}
-
-/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/
-static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d,
- LodePNGBitReader* reader) {
- /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/
- unsigned error = 0;
- unsigned n, HLIT, HDIST, HCLEN, i;
-
- /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/
- unsigned* bitlen_ll = 0; /*lit,len code lengths*/
- unsigned* bitlen_d = 0; /*dist code lengths*/
- /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/
- unsigned* bitlen_cl = 0;
- HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/
-
- if(!ensureBits17(reader, 14)) return 49; /*error: the bit pointer is or will go past the memory*/
-
- /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/
- HLIT = readBits(reader, 5) + 257;
- /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/
- HDIST = readBits(reader, 5) + 1;
- /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/
- HCLEN = readBits(reader, 4) + 4;
-
- bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned));
- if(!bitlen_cl) return 83 /*alloc fail*/;
-
- HuffmanTree_init(&tree_cl);
-
- while(!error) {
- /*read the code length codes out of 3 * (amount of code length codes) bits*/
- if(lodepng_gtofl(reader->bp, HCLEN * 3, reader->bitsize)) {
- ERROR_BREAK(50); /*error: the bit pointer is or will go past the memory*/
- }
- for(i = 0; i != HCLEN; ++i) {
- ensureBits9(reader, 3); /*out of bounds already checked above */
- bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3);
- }
- for(i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) {
- bitlen_cl[CLCL_ORDER[i]] = 0;
- }
-
- error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7);
- if(error) break;
-
- /*now we can use this tree to read the lengths for the tree that this function will return*/
- bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
- bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
- if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/);
- lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(*bitlen_ll));
- lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(*bitlen_d));
-
- /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/
- i = 0;
- while(i < HLIT + HDIST) {
- unsigned code;
- ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/
- code = huffmanDecodeSymbol(reader, &tree_cl);
- if(code <= 15) /*a length code*/ {
- if(i < HLIT) bitlen_ll[i] = code;
- else bitlen_d[i - HLIT] = code;
- ++i;
- } else if(code == 16) /*repeat previous*/ {
- unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/
- unsigned value; /*set value to the previous code*/
-
- if(i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/
-
- replength += readBits(reader, 2);
-
- if(i < HLIT + 1) value = bitlen_ll[i - 1];
- else value = bitlen_d[i - HLIT - 1];
- /*repeat this value in the next lengths*/
- for(n = 0; n < replength; ++n) {
- if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/
- if(i < HLIT) bitlen_ll[i] = value;
- else bitlen_d[i - HLIT] = value;
- ++i;
- }
- } else if(code == 17) /*repeat "0" 3-10 times*/ {
- unsigned replength = 3; /*read in the bits that indicate repeat length*/
- replength += readBits(reader, 3);
-
- /*repeat this value in the next lengths*/
- for(n = 0; n < replength; ++n) {
- if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/
-
- if(i < HLIT) bitlen_ll[i] = 0;
- else bitlen_d[i - HLIT] = 0;
- ++i;
- }
- } else if(code == 18) /*repeat "0" 11-138 times*/ {
- unsigned replength = 11; /*read in the bits that indicate repeat length*/
- replength += readBits(reader, 7);
-
- /*repeat this value in the next lengths*/
- for(n = 0; n < replength; ++n) {
- if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/
-
- if(i < HLIT) bitlen_ll[i] = 0;
- else bitlen_d[i - HLIT] = 0;
- ++i;
- }
- } else /*if(code == INVALIDSYMBOL)*/ {
- ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
- }
- /*check if any of the ensureBits above went out of bounds*/
- if(reader->bp > reader->bitsize) {
- /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
- (10=no endcode, 11=wrong jump outside of tree)*/
- /* TODO: revise error codes 10,11,50: the above comment is no longer valid */
- ERROR_BREAK(50); /*error, bit pointer jumps past memory*/
- }
- }
- if(error) break;
-
- if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/
-
- /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/
- error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15);
- if(error) break;
- error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15);
-
- break; /*end of error-while*/
- }
-
- lodepng_free(bitlen_cl);
- lodepng_free(bitlen_ll);
- lodepng_free(bitlen_d);
- HuffmanTree_cleanup(&tree_cl);
-
- return error;
-}
-
-/*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/
-static unsigned inflateHuffmanBlock(ucvector* out, LodePNGBitReader* reader,
- unsigned btype, size_t max_output_size) {
- unsigned error = 0;
- HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/
- HuffmanTree tree_d; /*the huffman tree for distance codes*/
-
- HuffmanTree_init(&tree_ll);
- HuffmanTree_init(&tree_d);
-
- if(btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d);
- else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader);
-
- while(!error) /*decode all symbols until end reached, breaks at end code*/ {
- /*code_ll is literal, length or end code*/
- unsigned code_ll;
- ensureBits25(reader, 20); /* up to 15 for the huffman symbol, up to 5 for the length extra bits */
- code_ll = huffmanDecodeSymbol(reader, &tree_ll);
- if(code_ll <= 255) /*literal symbol*/ {
- if(!ucvector_resize(out, out->size + 1)) ERROR_BREAK(83 /*alloc fail*/);
- out->data[out->size - 1] = (unsigned char)code_ll;
- } else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ {
- unsigned code_d, distance;
- unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/
- size_t start, backward, length;
-
- /*part 1: get length base*/
- length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX];
-
- /*part 2: get extra bits and add the value of that to length*/
- numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX];
- if(numextrabits_l != 0) {
- /* bits already ensured above */
- length += readBits(reader, numextrabits_l);
- }
-
- /*part 3: get distance code*/
- ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */
- code_d = huffmanDecodeSymbol(reader, &tree_d);
- if(code_d > 29) {
- if(code_d <= 31) {
- ERROR_BREAK(18); /*error: invalid distance code (30-31 are never used)*/
- } else /* if(code_d == INVALIDSYMBOL) */{
- ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
- }
- }
- distance = DISTANCEBASE[code_d];
-
- /*part 4: get extra bits from distance*/
- numextrabits_d = DISTANCEEXTRA[code_d];
- if(numextrabits_d != 0) {
- /* bits already ensured above */
- distance += readBits(reader, numextrabits_d);
- }
-
- /*part 5: fill in all the out[n] values based on the length and dist*/
- start = out->size;
- if(distance > start) ERROR_BREAK(52); /*too long backward distance*/
- backward = start - distance;
-
- if(!ucvector_resize(out, out->size + length)) ERROR_BREAK(83 /*alloc fail*/);
- if(distance < length) {
- size_t forward;
- lodepng_memcpy(out->data + start, out->data + backward, distance);
- start += distance;
- for(forward = distance; forward < length; ++forward) {
- out->data[start++] = out->data[backward++];
- }
- } else {
- lodepng_memcpy(out->data + start, out->data + backward, length);
- }
- } else if(code_ll == 256) {
- break; /*end code, break the loop*/
- } else /*if(code_ll == INVALIDSYMBOL)*/ {
- ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/
- }
- /*check if any of the ensureBits above went out of bounds*/
- if(reader->bp > reader->bitsize) {
- /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
- (10=no endcode, 11=wrong jump outside of tree)*/
- /* TODO: revise error codes 10,11,50: the above comment is no longer valid */
- ERROR_BREAK(51); /*error, bit pointer jumps past memory*/
- }
- if(max_output_size && out->size > max_output_size) {
- ERROR_BREAK(109); /*error, larger than max size*/
- }
- }
-
- HuffmanTree_cleanup(&tree_ll);
- HuffmanTree_cleanup(&tree_d);
-
- return error;
-}
-
-static unsigned inflateNoCompression(ucvector* out, LodePNGBitReader* reader,
- const LodePNGDecompressSettings* settings) {
- size_t bytepos;
- size_t size = reader->size;
- unsigned LEN, NLEN, error = 0;
-
- /*go to first boundary of byte*/
- bytepos = (reader->bp + 7u) >> 3u;
-
- /*read LEN (2 bytes) and NLEN (2 bytes)*/
- if(bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/
- LEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2;
- NLEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2;
-
- /*check if 16-bit NLEN is really the one's complement of LEN*/
- if(!settings->ignore_nlen && LEN + NLEN != 65535) {
- return 21; /*error: NLEN is not one's complement of LEN*/
- }
-
- if(!ucvector_resize(out, out->size + LEN)) return 83; /*alloc fail*/
-
- /*read the literal data: LEN bytes are now stored in the out buffer*/
- if(bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/
-
- lodepng_memcpy(out->data + out->size - LEN, reader->data + bytepos, LEN);
- bytepos += LEN;
-
- reader->bp = bytepos << 3u;
-
- return error;
-}
-
-static unsigned lodepng_inflatev(ucvector* out,
- const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings) {
- unsigned BFINAL = 0;
- LodePNGBitReader reader;
- unsigned error = LodePNGBitReader_init(&reader, in, insize);
-
- if(error) return error;
-
- while(!BFINAL) {
- unsigned BTYPE;
- if(!ensureBits9(&reader, 3)) return 52; /*error, bit pointer will jump past memory*/
- BFINAL = readBits(&reader, 1);
- BTYPE = readBits(&reader, 2);
-
- if(BTYPE == 3) return 20; /*error: invalid BTYPE*/
- else if(BTYPE == 0) error = inflateNoCompression(out, &reader, settings); /*no compression*/
- else error = inflateHuffmanBlock(out, &reader, BTYPE, settings->max_output_size); /*compression, BTYPE 01 or 10*/
- if(!error && settings->max_output_size && out->size > settings->max_output_size) error = 109;
- if(error) break;
- }
-
- return error;
-}
-
-unsigned lodepng_inflate(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings) {
- ucvector v = ucvector_init(*out, *outsize);
- unsigned error = lodepng_inflatev(&v, in, insize, settings);
- *out = v.data;
- *outsize = v.size;
- return error;
-}
-
-static unsigned inflatev(ucvector* out, const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings) {
- if(settings->custom_inflate) {
- unsigned error = settings->custom_inflate(&out->data, &out->size, in, insize, settings);
- out->allocsize = out->size;
- if(error) {
- /*the custom inflate is allowed to have its own error codes, however, we translate it to code 110*/
- error = 110;
- /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
- if(settings->max_output_size && out->size > settings->max_output_size) error = 109;
- }
- return error;
- } else {
- return lodepng_inflatev(out, in, insize, settings);
- }
-}
-
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Deflator (Compressor) / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258;
-
-/*search the index in the array, that has the largest value smaller than or equal to the given value,
-given array must be sorted (if no value is smaller, it returns the size of the given array)*/
-static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) {
- /*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/
- size_t left = 1;
- size_t right = array_size - 1;
-
- while(left <= right) {
- size_t mid = (left + right) >> 1;
- if(array[mid] >= value) right = mid - 1;
- else left = mid + 1;
- }
- if(left >= array_size || array[left] > value) left--;
- return left;
-}
-
-static void addLengthDistance(uivector* values, size_t length, size_t distance) {
- /*values in encoded vector are those used by deflate:
- 0-255: literal bytes
- 256: end
- 257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits)
- 286-287: invalid*/
-
- unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length);
- unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]);
- unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance);
- unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]);
-
- size_t pos = values->size;
- /*TODO: return error when this fails (out of memory)*/
- unsigned ok = uivector_resize(values, values->size + 4);
- if(ok) {
- values->data[pos + 0] = length_code + FIRST_LENGTH_CODE_INDEX;
- values->data[pos + 1] = extra_length;
- values->data[pos + 2] = dist_code;
- values->data[pos + 3] = extra_distance;
- }
-}
-
-/*3 bytes of data get encoded into two bytes. The hash cannot use more than 3
-bytes as input because 3 is the minimum match length for deflate*/
-static const unsigned HASH_NUM_VALUES = 65536;
-static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/
-
-typedef struct Hash {
- int* head; /*hash value to head circular pos - can be outdated if went around window*/
- /*circular pos to prev circular pos*/
- unsigned short* chain;
- int* val; /*circular pos to hash value*/
-
- /*TODO: do this not only for zeros but for any repeated byte. However for PNG
- it's always going to be the zeros that dominate, so not important for PNG*/
- int* headz; /*similar to head, but for chainz*/
- unsigned short* chainz; /*those with same amount of zeros*/
- unsigned short* zeros; /*length of zeros streak, used as a second hash chain*/
-} Hash;
-
-static unsigned hash_init(Hash* hash, unsigned windowsize) {
- unsigned i;
- hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES);
- hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize);
- hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
-
- hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
- hash->headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1));
- hash->chainz = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
-
- if(!hash->head || !hash->chain || !hash->val || !hash->headz|| !hash->chainz || !hash->zeros) {
- return 83; /*alloc fail*/
- }
-
- /*initialize hash table*/
- for(i = 0; i != HASH_NUM_VALUES; ++i) hash->head[i] = -1;
- for(i = 0; i != windowsize; ++i) hash->val[i] = -1;
- for(i = 0; i != windowsize; ++i) hash->chain[i] = i; /*same value as index indicates uninitialized*/
-
- for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash->headz[i] = -1;
- for(i = 0; i != windowsize; ++i) hash->chainz[i] = i; /*same value as index indicates uninitialized*/
-
- return 0;
-}
-
-static void hash_cleanup(Hash* hash) {
- lodepng_free(hash->head);
- lodepng_free(hash->val);
- lodepng_free(hash->chain);
-
- lodepng_free(hash->zeros);
- lodepng_free(hash->headz);
- lodepng_free(hash->chainz);
-}
-
-
-
-static unsigned getHash(const unsigned char* data, size_t size, size_t pos) {
- unsigned result = 0;
- if(pos + 2 < size) {
- /*A simple shift and xor hash is used. Since the data of PNGs is dominated
- by zeroes due to the filters, a better hash does not have a significant
- effect on speed in traversing the chain, and causes more time spend on
- calculating the hash.*/
- result ^= ((unsigned)data[pos + 0] << 0u);
- result ^= ((unsigned)data[pos + 1] << 4u);
- result ^= ((unsigned)data[pos + 2] << 8u);
- } else {
- size_t amount, i;
- if(pos >= size) return 0;
- amount = size - pos;
- for(i = 0; i != amount; ++i) result ^= ((unsigned)data[pos + i] << (i * 8u));
- }
- return result & HASH_BIT_MASK;
-}
-
-static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) {
- const unsigned char* start = data + pos;
- const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH;
- if(end > data + size) end = data + size;
- data = start;
- while(data != end && *data == 0) ++data;
- /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/
- return (unsigned)(data - start);
-}
-
-/*wpos = pos & (windowsize - 1)*/
-static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros) {
- hash->val[wpos] = (int)hashval;
- if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval];
- hash->head[hashval] = (int)wpos;
-
- hash->zeros[wpos] = numzeros;
- if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros];
- hash->headz[numzeros] = (int)wpos;
-}
-
-/*
-LZ77-encode the data. Return value is error code. The input are raw bytes, the output
-is in the form of unsigned integers with codes representing for example literal bytes, or
-length/distance pairs.
-It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a
-sliding window (of windowsize) is used, and all past bytes in that window can be used as
-the "dictionary". A brute force search through all possible distances would be slow, and
-this hash technique is one out of several ways to speed this up.
-*/
-static unsigned encodeLZ77(uivector* out, Hash* hash,
- const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize,
- unsigned minmatch, unsigned nicematch, unsigned lazymatching) {
- size_t pos;
- unsigned i, error = 0;
- /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/
- unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8u;
- unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64;
-
- unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/
- unsigned numzeros = 0;
-
- unsigned offset; /*the offset represents the distance in LZ77 terminology*/
- unsigned length;
- unsigned lazy = 0;
- unsigned lazylength = 0, lazyoffset = 0;
- unsigned hashval;
- unsigned current_offset, current_length;
- unsigned prev_offset;
- const unsigned char *lastptr, *foreptr, *backptr;
- unsigned hashpos;
-
- if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/
- if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/
-
- if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH;
-
- for(pos = inpos; pos < insize; ++pos) {
- size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/
- unsigned chainlength = 0;
-
- hashval = getHash(in, insize, pos);
-
- if(usezeros && hashval == 0) {
- if(numzeros == 0) numzeros = countZeros(in, insize, pos);
- else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
- } else {
- numzeros = 0;
- }
-
- updateHashChain(hash, wpos, hashval, numzeros);
-
- /*the length and offset found for the current position*/
- length = 0;
- offset = 0;
-
- hashpos = hash->chain[wpos];
-
- lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH];
-
- /*search for the longest string*/
- prev_offset = 0;
- for(;;) {
- if(chainlength++ >= maxchainlength) break;
- current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize);
-
- if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/
- prev_offset = current_offset;
- if(current_offset > 0) {
- /*test the next characters*/
- foreptr = &in[pos];
- backptr = &in[pos - current_offset];
-
- /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/
- if(numzeros >= 3) {
- unsigned skip = hash->zeros[hashpos];
- if(skip > numzeros) skip = numzeros;
- backptr += skip;
- foreptr += skip;
- }
-
- while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ {
- ++backptr;
- ++foreptr;
- }
- current_length = (unsigned)(foreptr - &in[pos]);
-
- if(current_length > length) {
- length = current_length; /*the longest length*/
- offset = current_offset; /*the offset that is related to this longest length*/
- /*jump out once a length of max length is found (speed gain). This also jumps
- out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/
- if(current_length >= nicematch) break;
- }
- }
-
- if(hashpos == hash->chain[hashpos]) break;
-
- if(numzeros >= 3 && length > numzeros) {
- hashpos = hash->chainz[hashpos];
- if(hash->zeros[hashpos] != numzeros) break;
- } else {
- hashpos = hash->chain[hashpos];
- /*outdated hash value, happens if particular value was not encountered in whole last window*/
- if(hash->val[hashpos] != (int)hashval) break;
- }
- }
-
- if(lazymatching) {
- if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) {
- lazy = 1;
- lazylength = length;
- lazyoffset = offset;
- continue; /*try the next byte*/
- }
- if(lazy) {
- lazy = 0;
- if(pos == 0) ERROR_BREAK(81);
- if(length > lazylength + 1) {
- /*push the previous character as literal*/
- if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/);
- } else {
- length = lazylength;
- offset = lazyoffset;
- hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/
- hash->headz[numzeros] = -1; /*idem*/
- --pos;
- }
- }
- }
- if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/);
-
- /*encode it as length/distance pair or literal value*/
- if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ {
- if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
- } else if(length < minmatch || (length == 3 && offset > 4096)) {
- /*compensate for the fact that longer offsets have more extra bits, a
- length of only 3 may be not worth it then*/
- if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
- } else {
- addLengthDistance(out, length, offset);
- for(i = 1; i < length; ++i) {
- ++pos;
- wpos = pos & (windowsize - 1);
- hashval = getHash(in, insize, pos);
- if(usezeros && hashval == 0) {
- if(numzeros == 0) numzeros = countZeros(in, insize, pos);
- else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
- } else {
- numzeros = 0;
- }
- updateHashChain(hash, wpos, hashval, numzeros);
- }
- }
- } /*end of the loop through each character of input*/
-
- return error;
-}
-
-/* /////////////////////////////////////////////////////////////////////////// */
-
-static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) {
- /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte,
- 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/
-
- size_t i, numdeflateblocks = (datasize + 65534u) / 65535u;
- unsigned datapos = 0;
- for(i = 0; i != numdeflateblocks; ++i) {
- unsigned BFINAL, BTYPE, LEN, NLEN;
- unsigned char firstbyte;
- size_t pos = out->size;
-
- BFINAL = (i == numdeflateblocks - 1);
- BTYPE = 0;
-
- LEN = 65535;
- if(datasize - datapos < 65535u) LEN = (unsigned)datasize - datapos;
- NLEN = 65535 - LEN;
-
- if(!ucvector_resize(out, out->size + LEN + 5)) return 83; /*alloc fail*/
-
- firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1u) << 1u) + ((BTYPE & 2u) << 1u));
- out->data[pos + 0] = firstbyte;
- out->data[pos + 1] = (unsigned char)(LEN & 255);
- out->data[pos + 2] = (unsigned char)(LEN >> 8u);
- out->data[pos + 3] = (unsigned char)(NLEN & 255);
- out->data[pos + 4] = (unsigned char)(NLEN >> 8u);
- lodepng_memcpy(out->data + pos + 5, data + datapos, LEN);
- datapos += LEN;
- }
-
- return 0;
-}
-
-/*
-write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees.
-tree_ll: the tree for lit and len codes.
-tree_d: the tree for distance codes.
-*/
-static void writeLZ77data(LodePNGBitWriter* writer, const uivector* lz77_encoded,
- const HuffmanTree* tree_ll, const HuffmanTree* tree_d) {
- size_t i = 0;
- for(i = 0; i != lz77_encoded->size; ++i) {
- unsigned val = lz77_encoded->data[i];
- writeBitsReversed(writer, tree_ll->codes[val], tree_ll->lengths[val]);
- if(val > 256) /*for a length code, 3 more things have to be added*/ {
- unsigned length_index = val - FIRST_LENGTH_CODE_INDEX;
- unsigned n_length_extra_bits = LENGTHEXTRA[length_index];
- unsigned length_extra_bits = lz77_encoded->data[++i];
-
- unsigned distance_code = lz77_encoded->data[++i];
-
- unsigned distance_index = distance_code;
- unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index];
- unsigned distance_extra_bits = lz77_encoded->data[++i];
-
- writeBits(writer, length_extra_bits, n_length_extra_bits);
- writeBitsReversed(writer, tree_d->codes[distance_code], tree_d->lengths[distance_code]);
- writeBits(writer, distance_extra_bits, n_distance_extra_bits);
- }
- }
-}
-
-/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/
-static unsigned deflateDynamic(LodePNGBitWriter* writer, Hash* hash,
- const unsigned char* data, size_t datapos, size_t dataend,
- const LodePNGCompressSettings* settings, unsigned final) {
- unsigned error = 0;
-
- /*
- A block is compressed as follows: The PNG data is lz77 encoded, resulting in
- literal bytes and length/distance pairs. This is then huffman compressed with
- two huffman trees. One huffman tree is used for the lit and len values ("ll"),
- another huffman tree is used for the dist values ("d"). These two trees are
- stored using their code lengths, and to compress even more these code lengths
- are also run-length encoded and huffman compressed. This gives a huffman tree
- of code lengths "cl". The code lengths used to describe this third tree are
- the code length code lengths ("clcl").
- */
-
- /*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/
- uivector lz77_encoded;
- HuffmanTree tree_ll; /*tree for lit,len values*/
- HuffmanTree tree_d; /*tree for distance codes*/
- HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/
- unsigned* frequencies_ll = 0; /*frequency of lit,len codes*/
- unsigned* frequencies_d = 0; /*frequency of dist codes*/
- unsigned* frequencies_cl = 0; /*frequency of code length codes*/
- unsigned* bitlen_lld = 0; /*lit,len,dist code lengths (int bits), literally (without repeat codes).*/
- unsigned* bitlen_lld_e = 0; /*bitlen_lld encoded with repeat codes (this is a rudimentary run length compression)*/
- size_t datasize = dataend - datapos;
-
- /*
- If we could call "bitlen_cl" the the code length code lengths ("clcl"), that is the bit lengths of codes to represent
- tree_cl in CLCL_ORDER, then due to the huffman compression of huffman tree representations ("two levels"), there are
- some analogies:
- bitlen_lld is to tree_cl what data is to tree_ll and tree_d.
- bitlen_lld_e is to bitlen_lld what lz77_encoded is to data.
- bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded.
- */
-
- unsigned BFINAL = final;
- size_t i;
- size_t numcodes_ll, numcodes_d, numcodes_lld, numcodes_lld_e, numcodes_cl;
- unsigned HLIT, HDIST, HCLEN;
-
- uivector_init(&lz77_encoded);
- HuffmanTree_init(&tree_ll);
- HuffmanTree_init(&tree_d);
- HuffmanTree_init(&tree_cl);
- /* could fit on stack, but >1KB is on the larger side so allocate instead */
- frequencies_ll = (unsigned*)lodepng_malloc(286 * sizeof(*frequencies_ll));
- frequencies_d = (unsigned*)lodepng_malloc(30 * sizeof(*frequencies_d));
- frequencies_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));
-
- if(!frequencies_ll || !frequencies_d || !frequencies_cl) error = 83; /*alloc fail*/
-
- /*This while loop never loops due to a break at the end, it is here to
- allow breaking out of it to the cleanup phase on error conditions.*/
- while(!error) {
- lodepng_memset(frequencies_ll, 0, 286 * sizeof(*frequencies_ll));
- lodepng_memset(frequencies_d, 0, 30 * sizeof(*frequencies_d));
- lodepng_memset(frequencies_cl, 0, NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));
-
- if(settings->use_lz77) {
- error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
- settings->minmatch, settings->nicematch, settings->lazymatching);
- if(error) break;
- } else {
- if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/);
- for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/
- }
-
- /*Count the frequencies of lit, len and dist codes*/
- for(i = 0; i != lz77_encoded.size; ++i) {
- unsigned symbol = lz77_encoded.data[i];
- ++frequencies_ll[symbol];
- if(symbol > 256) {
- unsigned dist = lz77_encoded.data[i + 2];
- ++frequencies_d[dist];
- i += 3;
- }
- }
- frequencies_ll[256] = 1; /*there will be exactly 1 end code, at the end of the block*/
-
- /*Make both huffman trees, one for the lit and len codes, one for the dist codes*/
- error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll, 257, 286, 15);
- if(error) break;
- /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/
- error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d, 2, 30, 15);
- if(error) break;
-
- numcodes_ll = LODEPNG_MIN(tree_ll.numcodes, 286);
- numcodes_d = LODEPNG_MIN(tree_d.numcodes, 30);
- /*store the code lengths of both generated trees in bitlen_lld*/
- numcodes_lld = numcodes_ll + numcodes_d;
- bitlen_lld = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld));
- /*numcodes_lld_e never needs more size than bitlen_lld*/
- bitlen_lld_e = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld_e));
- if(!bitlen_lld || !bitlen_lld_e) ERROR_BREAK(83); /*alloc fail*/
- numcodes_lld_e = 0;
-
- for(i = 0; i != numcodes_ll; ++i) bitlen_lld[i] = tree_ll.lengths[i];
- for(i = 0; i != numcodes_d; ++i) bitlen_lld[numcodes_ll + i] = tree_d.lengths[i];
-
- /*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times),
- 17 (3-10 zeroes), 18 (11-138 zeroes)*/
- for(i = 0; i != numcodes_lld; ++i) {
- unsigned j = 0; /*amount of repetitions*/
- while(i + j + 1 < numcodes_lld && bitlen_lld[i + j + 1] == bitlen_lld[i]) ++j;
-
- if(bitlen_lld[i] == 0 && j >= 2) /*repeat code for zeroes*/ {
- ++j; /*include the first zero*/
- if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ {
- bitlen_lld_e[numcodes_lld_e++] = 17;
- bitlen_lld_e[numcodes_lld_e++] = j - 3;
- } else /*repeat code 18 supports max 138 zeroes*/ {
- if(j > 138) j = 138;
- bitlen_lld_e[numcodes_lld_e++] = 18;
- bitlen_lld_e[numcodes_lld_e++] = j - 11;
- }
- i += (j - 1);
- } else if(j >= 3) /*repeat code for value other than zero*/ {
- size_t k;
- unsigned num = j / 6u, rest = j % 6u;
- bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
- for(k = 0; k < num; ++k) {
- bitlen_lld_e[numcodes_lld_e++] = 16;
- bitlen_lld_e[numcodes_lld_e++] = 6 - 3;
- }
- if(rest >= 3) {
- bitlen_lld_e[numcodes_lld_e++] = 16;
- bitlen_lld_e[numcodes_lld_e++] = rest - 3;
- }
- else j -= rest;
- i += j;
- } else /*too short to benefit from repeat code*/ {
- bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
- }
- }
-
- /*generate tree_cl, the huffmantree of huffmantrees*/
- for(i = 0; i != numcodes_lld_e; ++i) {
- ++frequencies_cl[bitlen_lld_e[i]];
- /*after a repeat code come the bits that specify the number of repetitions,
- those don't need to be in the frequencies_cl calculation*/
- if(bitlen_lld_e[i] >= 16) ++i;
- }
-
- error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl,
- NUM_CODE_LENGTH_CODES, NUM_CODE_LENGTH_CODES, 7);
- if(error) break;
-
- /*compute amount of code-length-code-lengths to output*/
- numcodes_cl = NUM_CODE_LENGTH_CODES;
- /*trim zeros at the end (using CLCL_ORDER), but minimum size must be 4 (see HCLEN below)*/
- while(numcodes_cl > 4u && tree_cl.lengths[CLCL_ORDER[numcodes_cl - 1u]] == 0) {
- numcodes_cl--;
- }
-
- /*
- Write everything into the output
-
- After the BFINAL and BTYPE, the dynamic block consists out of the following:
- - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN
- - (HCLEN+4)*3 bits code lengths of code length alphabet
- - HLIT + 257 code lengths of lit/length alphabet (encoded using the code length
- alphabet, + possible repetition codes 16, 17, 18)
- - HDIST + 1 code lengths of distance alphabet (encoded using the code length
- alphabet, + possible repetition codes 16, 17, 18)
- - compressed data
- - 256 (end code)
- */
-
- /*Write block type*/
- writeBits(writer, BFINAL, 1);
- writeBits(writer, 0, 1); /*first bit of BTYPE "dynamic"*/
- writeBits(writer, 1, 1); /*second bit of BTYPE "dynamic"*/
-
- /*write the HLIT, HDIST and HCLEN values*/
- /*all three sizes take trimmed ending zeroes into account, done either by HuffmanTree_makeFromFrequencies
- or in the loop for numcodes_cl above, which saves space. */
- HLIT = (unsigned)(numcodes_ll - 257);
- HDIST = (unsigned)(numcodes_d - 1);
- HCLEN = (unsigned)(numcodes_cl - 4);
- writeBits(writer, HLIT, 5);
- writeBits(writer, HDIST, 5);
- writeBits(writer, HCLEN, 4);
-
- /*write the code lengths of the code length alphabet ("bitlen_cl")*/
- for(i = 0; i != numcodes_cl; ++i) writeBits(writer, tree_cl.lengths[CLCL_ORDER[i]], 3);
-
- /*write the lengths of the lit/len AND the dist alphabet*/
- for(i = 0; i != numcodes_lld_e; ++i) {
- writeBitsReversed(writer, tree_cl.codes[bitlen_lld_e[i]], tree_cl.lengths[bitlen_lld_e[i]]);
- /*extra bits of repeat codes*/
- if(bitlen_lld_e[i] == 16) writeBits(writer, bitlen_lld_e[++i], 2);
- else if(bitlen_lld_e[i] == 17) writeBits(writer, bitlen_lld_e[++i], 3);
- else if(bitlen_lld_e[i] == 18) writeBits(writer, bitlen_lld_e[++i], 7);
- }
-
- /*write the compressed data symbols*/
- writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
- /*error: the length of the end code 256 must be larger than 0*/
- if(tree_ll.lengths[256] == 0) ERROR_BREAK(64);
-
- /*write the end code*/
- writeBitsReversed(writer, tree_ll.codes[256], tree_ll.lengths[256]);
-
- break; /*end of error-while*/
- }
-
- /*cleanup*/
- uivector_cleanup(&lz77_encoded);
- HuffmanTree_cleanup(&tree_ll);
- HuffmanTree_cleanup(&tree_d);
- HuffmanTree_cleanup(&tree_cl);
- lodepng_free(frequencies_ll);
- lodepng_free(frequencies_d);
- lodepng_free(frequencies_cl);
- lodepng_free(bitlen_lld);
- lodepng_free(bitlen_lld_e);
-
- return error;
-}
-
-static unsigned deflateFixed(LodePNGBitWriter* writer, Hash* hash,
- const unsigned char* data,
- size_t datapos, size_t dataend,
- const LodePNGCompressSettings* settings, unsigned final) {
- HuffmanTree tree_ll; /*tree for literal values and length codes*/
- HuffmanTree tree_d; /*tree for distance codes*/
-
- unsigned BFINAL = final;
- unsigned error = 0;
- size_t i;
-
- HuffmanTree_init(&tree_ll);
- HuffmanTree_init(&tree_d);
-
- error = generateFixedLitLenTree(&tree_ll);
- if(!error) error = generateFixedDistanceTree(&tree_d);
-
- if(!error) {
- writeBits(writer, BFINAL, 1);
- writeBits(writer, 1, 1); /*first bit of BTYPE*/
- writeBits(writer, 0, 1); /*second bit of BTYPE*/
-
- if(settings->use_lz77) /*LZ77 encoded*/ {
- uivector lz77_encoded;
- uivector_init(&lz77_encoded);
- error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
- settings->minmatch, settings->nicematch, settings->lazymatching);
- if(!error) writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
- uivector_cleanup(&lz77_encoded);
- } else /*no LZ77, but still will be Huffman compressed*/ {
- for(i = datapos; i < dataend; ++i) {
- writeBitsReversed(writer, tree_ll.codes[data[i]], tree_ll.lengths[data[i]]);
- }
- }
- /*add END code*/
- if(!error) writeBitsReversed(writer,tree_ll.codes[256], tree_ll.lengths[256]);
- }
-
- /*cleanup*/
- HuffmanTree_cleanup(&tree_ll);
- HuffmanTree_cleanup(&tree_d);
-
- return error;
-}
-
-static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize,
- const LodePNGCompressSettings* settings) {
- unsigned error = 0;
- size_t i, blocksize, numdeflateblocks;
- Hash hash;
- LodePNGBitWriter writer;
-
- LodePNGBitWriter_init(&writer, out);
-
- if(settings->btype > 2) return 61;
- else if(settings->btype == 0) return deflateNoCompression(out, in, insize);
- else if(settings->btype == 1) blocksize = insize;
- else /*if(settings->btype == 2)*/ {
- /*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/
- blocksize = insize / 8u + 8;
- if(blocksize < 65536) blocksize = 65536;
- if(blocksize > 262144) blocksize = 262144;
- }
-
- numdeflateblocks = (insize + blocksize - 1) / blocksize;
- if(numdeflateblocks == 0) numdeflateblocks = 1;
-
- error = hash_init(&hash, settings->windowsize);
-
- if(!error) {
- for(i = 0; i != numdeflateblocks && !error; ++i) {
- unsigned final = (i == numdeflateblocks - 1);
- size_t start = i * blocksize;
- size_t end = start + blocksize;
- if(end > insize) end = insize;
-
- if(settings->btype == 1) error = deflateFixed(&writer, &hash, in, start, end, settings, final);
- else if(settings->btype == 2) error = deflateDynamic(&writer, &hash, in, start, end, settings, final);
- }
- }
-
- hash_cleanup(&hash);
-
- return error;
-}
-
-unsigned lodepng_deflate(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGCompressSettings* settings) {
- ucvector v = ucvector_init(*out, *outsize);
- unsigned error = lodepng_deflatev(&v, in, insize, settings);
- *out = v.data;
- *outsize = v.size;
- return error;
-}
-
-static unsigned deflate(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGCompressSettings* settings) {
- if(settings->custom_deflate) {
- unsigned error = settings->custom_deflate(out, outsize, in, insize, settings);
- /*the custom deflate is allowed to have its own error codes, however, we translate it to code 111*/
- return error ? 111 : 0;
- } else {
- return lodepng_deflate(out, outsize, in, insize, settings);
- }
-}
-
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Adler32 / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) {
- unsigned s1 = adler & 0xffffu;
- unsigned s2 = (adler >> 16u) & 0xffffu;
-
- while(len != 0u) {
- unsigned i;
- /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/
- unsigned amount = len > 5552u ? 5552u : len;
- len -= amount;
- for(i = 0; i != amount; ++i) {
- s1 += (*data++);
- s2 += s1;
- }
- s1 %= 65521u;
- s2 %= 65521u;
- }
-
- return (s2 << 16u) | s1;
-}
-
-/*Return the adler32 of the bytes data[0..len-1]*/
-static unsigned adler32(const unsigned char* data, unsigned len) {
- return update_adler32(1u, data, len);
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Zlib / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-static unsigned lodepng_zlib_decompressv(ucvector* out,
- const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings) {
- unsigned error = 0;
- unsigned CM, CINFO, FDICT;
-
- if(insize < 2) return 53; /*error, size of zlib data too small*/
- /*read information from zlib header*/
- if((in[0] * 256 + in[1]) % 31 != 0) {
- /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/
- return 24;
- }
-
- CM = in[0] & 15;
- CINFO = (in[0] >> 4) & 15;
- /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/
- FDICT = (in[1] >> 5) & 1;
- /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/
-
- if(CM != 8 || CINFO > 7) {
- /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/
- return 25;
- }
- if(FDICT != 0) {
- /*error: the specification of PNG says about the zlib stream:
- "The additional flags shall not specify a preset dictionary."*/
- return 26;
- }
-
- error = inflatev(out, in + 2, insize - 2, settings);
- if(error) return error;
-
- if(!settings->ignore_adler32) {
- unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]);
- unsigned checksum = adler32(out->data, (unsigned)(out->size));
- if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/
- }
-
- return 0; /*no error*/
-}
-
-
-unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in,
- size_t insize, const LodePNGDecompressSettings* settings) {
- ucvector v = ucvector_init(*out, *outsize);
- unsigned error = lodepng_zlib_decompressv(&v, in, insize, settings);
- *out = v.data;
- *outsize = v.size;
- return error;
-}
-
-/*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */
-static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size,
- const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) {
- unsigned error;
- if(settings->custom_zlib) {
- error = settings->custom_zlib(out, outsize, in, insize, settings);
- if(error) {
- /*the custom zlib is allowed to have its own error codes, however, we translate it to code 110*/
- error = 110;
- /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
- if(settings->max_output_size && *outsize > settings->max_output_size) error = 109;
- }
- } else {
- ucvector v = ucvector_init(*out, *outsize);
- if(expected_size) {
- /*reserve the memory to avoid intermediate reallocations*/
- ucvector_resize(&v, *outsize + expected_size);
- v.size = *outsize;
- }
- error = lodepng_zlib_decompressv(&v, in, insize, settings);
- *out = v.data;
- *outsize = v.size;
- }
- return error;
-}
-
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
- size_t insize, const LodePNGCompressSettings* settings) {
- size_t i;
- unsigned error;
- unsigned char* deflatedata = 0;
- size_t deflatesize = 0;
-
- error = deflate(&deflatedata, &deflatesize, in, insize, settings);
-
- *out = NULL;
- *outsize = 0;
- if(!error) {
- *outsize = deflatesize + 6;
- *out = (unsigned char*)lodepng_malloc(*outsize);
- if(!*out) error = 83; /*alloc fail*/
- }
-
- if(!error) {
- unsigned ADLER32 = adler32(in, (unsigned)insize);
- /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/
- unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/
- unsigned FLEVEL = 0;
- unsigned FDICT = 0;
- unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64;
- unsigned FCHECK = 31 - CMFFLG % 31;
- CMFFLG += FCHECK;
-
- (*out)[0] = (unsigned char)(CMFFLG >> 8);
- (*out)[1] = (unsigned char)(CMFFLG & 255);
- for(i = 0; i != deflatesize; ++i) (*out)[i + 2] = deflatedata[i];
- lodepng_set32bitInt(&(*out)[*outsize - 4], ADLER32);
- }
-
- lodepng_free(deflatedata);
- return error;
-}
-
-/* compress using the default or custom zlib function */
-static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
- size_t insize, const LodePNGCompressSettings* settings) {
- if(settings->custom_zlib) {
- unsigned error = settings->custom_zlib(out, outsize, in, insize, settings);
- /*the custom zlib is allowed to have its own error codes, however, we translate it to code 111*/
- return error ? 111 : 0;
- } else {
- return lodepng_zlib_compress(out, outsize, in, insize, settings);
- }
-}
-
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#else /*no LODEPNG_COMPILE_ZLIB*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size,
- const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) {
- if(!settings->custom_zlib) return 87; /*no custom zlib function provided */
- (void)expected_size;
- return settings->custom_zlib(out, outsize, in, insize, settings);
-}
-#endif /*LODEPNG_COMPILE_DECODER*/
-#ifdef LODEPNG_COMPILE_ENCODER
-static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
- size_t insize, const LodePNGCompressSettings* settings) {
- if(!settings->custom_zlib) return 87; /*no custom zlib function provided */
- return settings->custom_zlib(out, outsize, in, insize, settings);
-}
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#endif /*LODEPNG_COMPILE_ZLIB*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-/*this is a good tradeoff between speed and compression ratio*/
-#define DEFAULT_WINDOWSIZE 2048
-
-void lodepng_compress_settings_init(LodePNGCompressSettings* settings) {
- /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/
- settings->btype = 2;
- settings->use_lz77 = 1;
- settings->windowsize = DEFAULT_WINDOWSIZE;
- settings->minmatch = 3;
- settings->nicematch = 128;
- settings->lazymatching = 1;
-
- settings->custom_zlib = 0;
- settings->custom_deflate = 0;
- settings->custom_context = 0;
-}
-
-const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0};
-
-
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) {
- settings->ignore_adler32 = 0;
- settings->ignore_nlen = 0;
- settings->max_output_size = 0;
-
- settings->custom_zlib = 0;
- settings->custom_inflate = 0;
- settings->custom_context = 0;
-}
-
-const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0, 0, 0};
-
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* // End of Zlib related code. Begin of PNG related code. // */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_PNG
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / CRC32 / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-
-#ifndef LODEPNG_NO_COMPILE_CRC
-/* CRC polynomial: 0xedb88320 */
-static unsigned lodepng_crc32_table[256] = {
- 0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u, 3915621685u, 2657392035u,
- 249268274u, 2044508324u, 3772115230u, 2547177864u, 162941995u, 2125561021u, 3887607047u, 2428444049u,
- 498536548u, 1789927666u, 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u,
- 325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u, 4195302755u, 2366115317u,
- 997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u,
- 901097722u, 1119000684u, 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u,
- 651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u, 3485111705u, 3099436303u,
- 671266974u, 1594198024u, 3322730930u, 2970347812u, 795835527u, 1483230225u, 3244367275u, 3060149565u,
- 1994146192u, 31158534u, 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u,
- 2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u, 2439277719u, 3865271297u,
- 1802195444u, 476864866u, 2238001368u, 4066508878u, 1812370925u, 453092731u, 2181625025u, 4111451223u,
- 1706088902u, 314042704u, 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u,
- 1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u,
- 1131014506u, 879679996u, 2909243462u, 3663771856u, 1141124467u, 855842277u, 2852801631u, 3708648649u,
- 1342533948u, 654459306u, 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u,
- 1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u, 3082640443u, 3233442989u,
- 3988292384u, 2596254646u, 62317068u, 1957810842u, 3939845945u, 2647816111u, 81470997u, 1943803523u,
- 3814918930u, 2489596804u, 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u,
- 4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u, 426522225u, 1852507879u,
- 4275313526u, 2312317920u, 282753626u, 1742555852u, 4189708143u, 2394877945u, 397917763u, 1622183637u,
- 3604390888u, 2714866558u, 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u,
- 3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u, 829329135u, 1181335161u,
- 3412177804u, 3160834842u, 628085408u, 1382605366u, 3423369109u, 3138078467u, 570562233u, 1426400815u,
- 3317316542u, 2998733608u, 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u,
- 2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u, 1913087877u, 83908371u,
- 2512341634u, 3803740692u, 2075208622u, 213261112u, 2463272603u, 3855990285u, 2094854071u, 198958881u,
- 2262029012u, 4057260610u, 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u,
- 2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u, 1634467795u, 376229701u,
- 2685067896u, 3608007406u, 1308918612u, 956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u,
- 2932959818u, 3654703836u, 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u,
- 3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u, 1423857449u, 601450431u,
- 3009837614u, 3294710456u, 1567103746u, 711928724u, 3020668471u, 3272380065u, 1510334235u, 755167117u
-};
-
-/*Return the CRC of the bytes buf[0..len-1].*/
-unsigned lodepng_crc32(const unsigned char* data, size_t length) {
- unsigned r = 0xffffffffu;
- size_t i;
- for(i = 0; i < length; ++i) {
- r = lodepng_crc32_table[(r ^ data[i]) & 0xffu] ^ (r >> 8u);
- }
- return r ^ 0xffffffffu;
-}
-#else /* !LODEPNG_NO_COMPILE_CRC */
-unsigned lodepng_crc32(const unsigned char* data, size_t length);
-#endif /* !LODEPNG_NO_COMPILE_CRC */
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Reading and writing PNG color channel bits / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first,
-so LodePNGBitWriter and LodePNGBitReader can't be used for those. */
-
-static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) {
- unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1);
- ++(*bitpointer);
- return result;
-}
-
-/* TODO: make this faster */
-static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) {
- unsigned result = 0;
- size_t i;
- for(i = 0 ; i < nbits; ++i) {
- result <<= 1u;
- result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream);
- }
- return result;
-}
-
-static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) {
- /*the current bit in bitstream may be 0 or 1 for this to work*/
- if(bit == 0) bitstream[(*bitpointer) >> 3u] &= (unsigned char)(~(1u << (7u - ((*bitpointer) & 7u))));
- else bitstream[(*bitpointer) >> 3u] |= (1u << (7u - ((*bitpointer) & 7u)));
- ++(*bitpointer);
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / PNG chunks / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-unsigned lodepng_chunk_length(const unsigned char* chunk) {
- return lodepng_read32bitInt(&chunk[0]);
-}
-
-void lodepng_chunk_type(char type[5], const unsigned char* chunk) {
- unsigned i;
- for(i = 0; i != 4; ++i) type[i] = (char)chunk[4 + i];
- type[4] = 0; /*null termination char*/
-}
-
-unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) {
- if(lodepng_strlen(type) != 4) return 0;
- return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]);
-}
-
-unsigned char lodepng_chunk_ancillary(const unsigned char* chunk) {
- return((chunk[4] & 32) != 0);
-}
-
-unsigned char lodepng_chunk_private(const unsigned char* chunk) {
- return((chunk[6] & 32) != 0);
-}
-
-unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk) {
- return((chunk[7] & 32) != 0);
-}
-
-unsigned char* lodepng_chunk_data(unsigned char* chunk) {
- return &chunk[8];
-}
-
-const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk) {
- return &chunk[8];
-}
-
-unsigned lodepng_chunk_check_crc(const unsigned char* chunk) {
- unsigned length = lodepng_chunk_length(chunk);
- unsigned CRC = lodepng_read32bitInt(&chunk[length + 8]);
- /*the CRC is taken of the data and the 4 chunk type letters, not the length*/
- unsigned checksum = lodepng_crc32(&chunk[4], length + 4);
- if(CRC != checksum) return 1;
- else return 0;
-}
-
-void lodepng_chunk_generate_crc(unsigned char* chunk) {
- unsigned length = lodepng_chunk_length(chunk);
- unsigned CRC = lodepng_crc32(&chunk[4], length + 4);
- lodepng_set32bitInt(chunk + 8 + length, CRC);
-}
-
-unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end) {
- if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/
- if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
- && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
- /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
- return chunk + 8;
- } else {
- size_t total_chunk_length;
- unsigned char* result;
- if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
- result = chunk + total_chunk_length;
- if(result < chunk) return end; /*pointer overflow*/
- return result;
- }
-}
-
-const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end) {
- if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/
- if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
- && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
- /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
- return chunk + 8;
- } else {
- size_t total_chunk_length;
- const unsigned char* result;
- if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
- result = chunk + total_chunk_length;
- if(result < chunk) return end; /*pointer overflow*/
- return result;
- }
-}
-
-unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]) {
- for(;;) {
- if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */
- if(lodepng_chunk_type_equals(chunk, type)) return chunk;
- chunk = lodepng_chunk_next(chunk, end);
- }
-}
-
-const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]) {
- for(;;) {
- if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */
- if(lodepng_chunk_type_equals(chunk, type)) return chunk;
- chunk = lodepng_chunk_next_const(chunk, end);
- }
-}
-
-unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk) {
- unsigned i;
- size_t total_chunk_length, new_length;
- unsigned char *chunk_start, *new_buffer;
-
- if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return 77;
- if(lodepng_addofl(*outsize, total_chunk_length, &new_length)) return 77;
-
- new_buffer = (unsigned char*)lodepng_realloc(*out, new_length);
- if(!new_buffer) return 83; /*alloc fail*/
- (*out) = new_buffer;
- (*outsize) = new_length;
- chunk_start = &(*out)[new_length - total_chunk_length];
-
- for(i = 0; i != total_chunk_length; ++i) chunk_start[i] = chunk[i];
-
- return 0;
-}
-
-/*Sets length and name and allocates the space for data and crc but does not
-set data or crc yet. Returns the start of the chunk in chunk. The start of
-the data is at chunk + 8. To finalize chunk, add the data, then use
-lodepng_chunk_generate_crc */
-static unsigned lodepng_chunk_init(unsigned char** chunk,
- ucvector* out,
- unsigned length, const char* type) {
- size_t new_length = out->size;
- if(lodepng_addofl(new_length, length, &new_length)) return 77;
- if(lodepng_addofl(new_length, 12, &new_length)) return 77;
- if(!ucvector_resize(out, new_length)) return 83; /*alloc fail*/
- *chunk = out->data + new_length - length - 12u;
-
- /*1: length*/
- lodepng_set32bitInt(*chunk, length);
-
- /*2: chunk name (4 letters)*/
- lodepng_memcpy(*chunk + 4, type, 4);
-
- return 0;
-}
-
-/* like lodepng_chunk_create but with custom allocsize */
-static unsigned lodepng_chunk_createv(ucvector* out,
- unsigned length, const char* type, const unsigned char* data) {
- unsigned char* chunk;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, length, type));
-
- /*3: the data*/
- lodepng_memcpy(chunk + 8, data, length);
-
- /*4: CRC (of the chunkname characters and the data)*/
- lodepng_chunk_generate_crc(chunk);
-
- return 0;
-}
-
-unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize,
- unsigned length, const char* type, const unsigned char* data) {
- ucvector v = ucvector_init(*out, *outsize);
- unsigned error = lodepng_chunk_createv(&v, length, type, data);
- *out = v.data;
- *outsize = v.size;
- return error;
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / Color types, channels, bits / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype.
-Return value is a LodePNG error code.*/
-static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) {
- switch(colortype) {
- case LCT_GREY: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break;
- case LCT_RGB: if(!( bd == 8 || bd == 16)) return 37; break;
- case LCT_PALETTE: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break;
- case LCT_GREY_ALPHA: if(!( bd == 8 || bd == 16)) return 37; break;
- case LCT_RGBA: if(!( bd == 8 || bd == 16)) return 37; break;
- case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */
- default: return 31; /* invalid color type */
- }
- return 0; /*allowed color type / bits combination*/
-}
-
-static unsigned getNumColorChannels(LodePNGColorType colortype) {
- switch(colortype) {
- case LCT_GREY: return 1;
- case LCT_RGB: return 3;
- case LCT_PALETTE: return 1;
- case LCT_GREY_ALPHA: return 2;
- case LCT_RGBA: return 4;
- case LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */
- default: return 0; /*invalid color type*/
- }
-}
-
-static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) {
- /*bits per pixel is amount of channels * bits per channel*/
- return getNumColorChannels(colortype) * bitdepth;
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-void lodepng_color_mode_init(LodePNGColorMode* info) {
- info->key_defined = 0;
- info->key_r = info->key_g = info->key_b = 0;
- info->colortype = LCT_RGBA;
- info->bitdepth = 8;
- info->palette = 0;
- info->palettesize = 0;
-}
-
-/*allocates palette memory if needed, and initializes all colors to black*/
-static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) {
- size_t i;
- /*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/
- /*the palette must have room for up to 256 colors with 4 bytes each.*/
- if(!info->palette) info->palette = (unsigned char*)lodepng_malloc(1024);
- if(!info->palette) return; /*alloc fail*/
- for(i = 0; i != 256; ++i) {
- /*Initialize all unused colors with black, the value used for invalid palette indices.
- This is an error according to the PNG spec, but common PNG decoders make it black instead.
- That makes color conversion slightly faster due to no error handling needed.*/
- info->palette[i * 4 + 0] = 0;
- info->palette[i * 4 + 1] = 0;
- info->palette[i * 4 + 2] = 0;
- info->palette[i * 4 + 3] = 255;
- }
-}
-
-void lodepng_color_mode_cleanup(LodePNGColorMode* info) {
- lodepng_palette_clear(info);
-}
-
-unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) {
- lodepng_color_mode_cleanup(dest);
- lodepng_memcpy(dest, source, sizeof(LodePNGColorMode));
- if(source->palette) {
- dest->palette = (unsigned char*)lodepng_malloc(1024);
- if(!dest->palette && source->palettesize) return 83; /*alloc fail*/
- lodepng_memcpy(dest->palette, source->palette, source->palettesize * 4);
- }
- return 0;
-}
-
-LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) {
- LodePNGColorMode result;
- lodepng_color_mode_init(&result);
- result.colortype = colortype;
- result.bitdepth = bitdepth;
- return result;
-}
-
-static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) {
- size_t i;
- if(a->colortype != b->colortype) return 0;
- if(a->bitdepth != b->bitdepth) return 0;
- if(a->key_defined != b->key_defined) return 0;
- if(a->key_defined) {
- if(a->key_r != b->key_r) return 0;
- if(a->key_g != b->key_g) return 0;
- if(a->key_b != b->key_b) return 0;
- }
- if(a->palettesize != b->palettesize) return 0;
- for(i = 0; i != a->palettesize * 4; ++i) {
- if(a->palette[i] != b->palette[i]) return 0;
- }
- return 1;
-}
-
-void lodepng_palette_clear(LodePNGColorMode* info) {
- if(info->palette) lodepng_free(info->palette);
- info->palette = 0;
- info->palettesize = 0;
-}
-
-unsigned lodepng_palette_add(LodePNGColorMode* info,
- unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
- if(!info->palette) /*allocate palette if empty*/ {
- lodepng_color_mode_alloc_palette(info);
- if(!info->palette) return 83; /*alloc fail*/
- }
- if(info->palettesize >= 256) {
- return 108; /*too many palette values*/
- }
- info->palette[4 * info->palettesize + 0] = r;
- info->palette[4 * info->palettesize + 1] = g;
- info->palette[4 * info->palettesize + 2] = b;
- info->palette[4 * info->palettesize + 3] = a;
- ++info->palettesize;
- return 0;
-}
-
-/*calculate bits per pixel out of colortype and bitdepth*/
-unsigned lodepng_get_bpp(const LodePNGColorMode* info) {
- return lodepng_get_bpp_lct(info->colortype, info->bitdepth);
-}
-
-unsigned lodepng_get_channels(const LodePNGColorMode* info) {
- return getNumColorChannels(info->colortype);
-}
-
-unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info) {
- return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA;
-}
-
-unsigned lodepng_is_alpha_type(const LodePNGColorMode* info) {
- return (info->colortype & 4) != 0; /*4 or 6*/
-}
-
-unsigned lodepng_is_palette_type(const LodePNGColorMode* info) {
- return info->colortype == LCT_PALETTE;
-}
-
-unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info) {
- size_t i;
- for(i = 0; i != info->palettesize; ++i) {
- if(info->palette[i * 4 + 3] < 255) return 1;
- }
- return 0;
-}
-
-unsigned lodepng_can_have_alpha(const LodePNGColorMode* info) {
- return info->key_defined
- || lodepng_is_alpha_type(info)
- || lodepng_has_palette_alpha(info);
-}
-
-static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
- size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth);
- size_t n = (size_t)w * (size_t)h;
- return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u;
-}
-
-size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) {
- return lodepng_get_raw_size_lct(w, h, color->colortype, color->bitdepth);
-}
-
-
-#ifdef LODEPNG_COMPILE_PNG
-
-/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer,
-and in addition has one extra byte per line: the filter byte. So this gives a larger
-result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */
-static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) {
- /* + 1 for the filter byte, and possibly plus padding bits per line. */
- /* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */
- size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u;
- return (size_t)h * line;
-}
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*Safely checks whether size_t overflow can be caused due to amount of pixels.
-This check is overcautious rather than precise. If this check indicates no overflow,
-you can safely compute in a size_t (but not an unsigned):
--(size_t)w * (size_t)h * 8
--amount of bytes in IDAT (including filter, padding and Adam7 bytes)
--amount of bytes in raw color model
-Returns 1 if overflow possible, 0 if not.
-*/
-static int lodepng_pixel_overflow(unsigned w, unsigned h,
- const LodePNGColorMode* pngcolor, const LodePNGColorMode* rawcolor) {
- size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor));
- size_t numpixels, total;
- size_t line; /* bytes per line in worst case */
-
- if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1;
- if(lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */
-
- /* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */
- if(lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return 1;
- if(lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return 1;
-
- if(lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */
- if(lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */
-
- return 0; /* no overflow */
-}
-#endif /*LODEPNG_COMPILE_DECODER*/
-#endif /*LODEPNG_COMPILE_PNG*/
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-
-static void LodePNGUnknownChunks_init(LodePNGInfo* info) {
- unsigned i;
- for(i = 0; i != 3; ++i) info->unknown_chunks_data[i] = 0;
- for(i = 0; i != 3; ++i) info->unknown_chunks_size[i] = 0;
-}
-
-static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) {
- unsigned i;
- for(i = 0; i != 3; ++i) lodepng_free(info->unknown_chunks_data[i]);
-}
-
-static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) {
- unsigned i;
-
- LodePNGUnknownChunks_cleanup(dest);
-
- for(i = 0; i != 3; ++i) {
- size_t j;
- dest->unknown_chunks_size[i] = src->unknown_chunks_size[i];
- dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]);
- if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/
- for(j = 0; j < src->unknown_chunks_size[i]; ++j) {
- dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j];
- }
- }
-
- return 0;
-}
-
-/******************************************************************************/
-
-static void LodePNGText_init(LodePNGInfo* info) {
- info->text_num = 0;
- info->text_keys = NULL;
- info->text_strings = NULL;
-}
-
-static void LodePNGText_cleanup(LodePNGInfo* info) {
- size_t i;
- for(i = 0; i != info->text_num; ++i) {
- string_cleanup(&info->text_keys[i]);
- string_cleanup(&info->text_strings[i]);
- }
- lodepng_free(info->text_keys);
- lodepng_free(info->text_strings);
-}
-
-static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
- size_t i = 0;
- dest->text_keys = NULL;
- dest->text_strings = NULL;
- dest->text_num = 0;
- for(i = 0; i != source->text_num; ++i) {
- CERROR_TRY_RETURN(lodepng_add_text(dest, source->text_keys[i], source->text_strings[i]));
- }
- return 0;
-}
-
-static unsigned lodepng_add_text_sized(LodePNGInfo* info, const char* key, const char* str, size_t size) {
- char** new_keys = (char**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1)));
- char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1)));
-
- if(new_keys) info->text_keys = new_keys;
- if(new_strings) info->text_strings = new_strings;
-
- if(!new_keys || !new_strings) return 83; /*alloc fail*/
-
- ++info->text_num;
- info->text_keys[info->text_num - 1] = alloc_string(key);
- info->text_strings[info->text_num - 1] = alloc_string_sized(str, size);
- if(!info->text_keys[info->text_num - 1] || !info->text_strings[info->text_num - 1]) return 83; /*alloc fail*/
-
- return 0;
-}
-
-unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) {
- return lodepng_add_text_sized(info, key, str, lodepng_strlen(str));
-}
-
-void lodepng_clear_text(LodePNGInfo* info) {
- LodePNGText_cleanup(info);
-}
-
-/******************************************************************************/
-
-static void LodePNGIText_init(LodePNGInfo* info) {
- info->itext_num = 0;
- info->itext_keys = NULL;
- info->itext_langtags = NULL;
- info->itext_transkeys = NULL;
- info->itext_strings = NULL;
-}
-
-static void LodePNGIText_cleanup(LodePNGInfo* info) {
- size_t i;
- for(i = 0; i != info->itext_num; ++i) {
- string_cleanup(&info->itext_keys[i]);
- string_cleanup(&info->itext_langtags[i]);
- string_cleanup(&info->itext_transkeys[i]);
- string_cleanup(&info->itext_strings[i]);
- }
- lodepng_free(info->itext_keys);
- lodepng_free(info->itext_langtags);
- lodepng_free(info->itext_transkeys);
- lodepng_free(info->itext_strings);
-}
-
-static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
- size_t i = 0;
- dest->itext_keys = NULL;
- dest->itext_langtags = NULL;
- dest->itext_transkeys = NULL;
- dest->itext_strings = NULL;
- dest->itext_num = 0;
- for(i = 0; i != source->itext_num; ++i) {
- CERROR_TRY_RETURN(lodepng_add_itext(dest, source->itext_keys[i], source->itext_langtags[i],
- source->itext_transkeys[i], source->itext_strings[i]));
- }
- return 0;
-}
-
-void lodepng_clear_itext(LodePNGInfo* info) {
- LodePNGIText_cleanup(info);
-}
-
-static unsigned lodepng_add_itext_sized(LodePNGInfo* info, const char* key, const char* langtag,
- const char* transkey, const char* str, size_t size) {
- char** new_keys = (char**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1)));
- char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1)));
- char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1)));
- char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1)));
-
- if(new_keys) info->itext_keys = new_keys;
- if(new_langtags) info->itext_langtags = new_langtags;
- if(new_transkeys) info->itext_transkeys = new_transkeys;
- if(new_strings) info->itext_strings = new_strings;
-
- if(!new_keys || !new_langtags || !new_transkeys || !new_strings) return 83; /*alloc fail*/
-
- ++info->itext_num;
-
- info->itext_keys[info->itext_num - 1] = alloc_string(key);
- info->itext_langtags[info->itext_num - 1] = alloc_string(langtag);
- info->itext_transkeys[info->itext_num - 1] = alloc_string(transkey);
- info->itext_strings[info->itext_num - 1] = alloc_string_sized(str, size);
-
- return 0;
-}
-
-unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
- const char* transkey, const char* str) {
- return lodepng_add_itext_sized(info, key, langtag, transkey, str, lodepng_strlen(str));
-}
-
-/* same as set but does not delete */
-static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) {
- if(profile_size == 0) return 100; /*invalid ICC profile size*/
-
- info->iccp_name = alloc_string(name);
- info->iccp_profile = (unsigned char*)lodepng_malloc(profile_size);
-
- if(!info->iccp_name || !info->iccp_profile) return 83; /*alloc fail*/
-
- lodepng_memcpy(info->iccp_profile, profile, profile_size);
- info->iccp_profile_size = profile_size;
-
- return 0; /*ok*/
-}
-
-unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) {
- if(info->iccp_name) lodepng_clear_icc(info);
- info->iccp_defined = 1;
-
- return lodepng_assign_icc(info, name, profile, profile_size);
-}
-
-void lodepng_clear_icc(LodePNGInfo* info) {
- string_cleanup(&info->iccp_name);
- lodepng_free(info->iccp_profile);
- info->iccp_profile = NULL;
- info->iccp_profile_size = 0;
- info->iccp_defined = 0;
-}
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-void lodepng_info_init(LodePNGInfo* info) {
- lodepng_color_mode_init(&info->color);
- info->interlace_method = 0;
- info->compression_method = 0;
- info->filter_method = 0;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- info->background_defined = 0;
- info->background_r = info->background_g = info->background_b = 0;
-
- LodePNGText_init(info);
- LodePNGIText_init(info);
-
- info->time_defined = 0;
- info->phys_defined = 0;
-
- info->gama_defined = 0;
- info->chrm_defined = 0;
- info->srgb_defined = 0;
- info->iccp_defined = 0;
- info->iccp_name = NULL;
- info->iccp_profile = NULL;
-
- LodePNGUnknownChunks_init(info);
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-}
-
-void lodepng_info_cleanup(LodePNGInfo* info) {
- lodepng_color_mode_cleanup(&info->color);
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- LodePNGText_cleanup(info);
- LodePNGIText_cleanup(info);
-
- lodepng_clear_icc(info);
-
- LodePNGUnknownChunks_cleanup(info);
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-}
-
-unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
- lodepng_info_cleanup(dest);
- lodepng_memcpy(dest, source, sizeof(LodePNGInfo));
- lodepng_color_mode_init(&dest->color);
- CERROR_TRY_RETURN(lodepng_color_mode_copy(&dest->color, &source->color));
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- CERROR_TRY_RETURN(LodePNGText_copy(dest, source));
- CERROR_TRY_RETURN(LodePNGIText_copy(dest, source));
- if(source->iccp_defined) {
- CERROR_TRY_RETURN(lodepng_assign_icc(dest, source->iccp_name, source->iccp_profile, source->iccp_profile_size));
- }
-
- LodePNGUnknownChunks_init(dest);
- CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source));
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- return 0;
-}
-
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/
-static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) {
- unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/
- /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/
- unsigned p = index & m;
- in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/
- in = in << (bits * (m - p));
- if(p == 0) out[index * bits / 8u] = in;
- else out[index * bits / 8u] |= in;
-}
-
-typedef struct ColorTree ColorTree;
-
-/*
-One node of a color tree
-This is the data structure used to count the number of unique colors and to get a palette
-index for a color. It's like an octree, but because the alpha channel is used too, each
-node has 16 instead of 8 children.
-*/
-struct ColorTree {
- ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/
- int index; /*the payload. Only has a meaningful value if this is in the last level*/
-};
-
-static void color_tree_init(ColorTree* tree) {
- lodepng_memset(tree->children, 0, 16 * sizeof(*tree->children));
- tree->index = -1;
-}
-
-static void color_tree_cleanup(ColorTree* tree) {
- int i;
- for(i = 0; i != 16; ++i) {
- if(tree->children[i]) {
- color_tree_cleanup(tree->children[i]);
- lodepng_free(tree->children[i]);
- }
- }
-}
-
-/*returns -1 if color not present, its index otherwise*/
-static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
- int bit = 0;
- for(bit = 0; bit < 8; ++bit) {
- int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
- if(!tree->children[i]) return -1;
- else tree = tree->children[i];
- }
- return tree ? tree->index : -1;
-}
-
-#ifdef LODEPNG_COMPILE_ENCODER
-static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
- return color_tree_get(tree, r, g, b, a) >= 0;
-}
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-/*color is not allowed to already exist.
-Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist")
-Returns error code, or 0 if ok*/
-static unsigned color_tree_add(ColorTree* tree,
- unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) {
- int bit;
- for(bit = 0; bit < 8; ++bit) {
- int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
- if(!tree->children[i]) {
- tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree));
- if(!tree->children[i]) return 83; /*alloc fail*/
- color_tree_init(tree->children[i]);
- }
- tree = tree->children[i];
- }
- tree->index = (int)index;
- return 0;
-}
-
-/*put a pixel, given its RGBA color, into image of any color type*/
-static unsigned rgba8ToPixel(unsigned char* out, size_t i,
- const LodePNGColorMode* mode, ColorTree* tree /*for palette*/,
- unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
- if(mode->colortype == LCT_GREY) {
- unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/
- if(mode->bitdepth == 8) out[i] = gray;
- else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray;
- else {
- /*take the most significant bits of gray*/
- gray = ((unsigned)gray >> (8u - mode->bitdepth)) & ((1u << mode->bitdepth) - 1u);
- addColorBits(out, i, mode->bitdepth, gray);
- }
- } else if(mode->colortype == LCT_RGB) {
- if(mode->bitdepth == 8) {
- out[i * 3 + 0] = r;
- out[i * 3 + 1] = g;
- out[i * 3 + 2] = b;
- } else {
- out[i * 6 + 0] = out[i * 6 + 1] = r;
- out[i * 6 + 2] = out[i * 6 + 3] = g;
- out[i * 6 + 4] = out[i * 6 + 5] = b;
- }
- } else if(mode->colortype == LCT_PALETTE) {
- int index = color_tree_get(tree, r, g, b, a);
- if(index < 0) return 82; /*color not in palette*/
- if(mode->bitdepth == 8) out[i] = index;
- else addColorBits(out, i, mode->bitdepth, (unsigned)index);
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/
- if(mode->bitdepth == 8) {
- out[i * 2 + 0] = gray;
- out[i * 2 + 1] = a;
- } else if(mode->bitdepth == 16) {
- out[i * 4 + 0] = out[i * 4 + 1] = gray;
- out[i * 4 + 2] = out[i * 4 + 3] = a;
- }
- } else if(mode->colortype == LCT_RGBA) {
- if(mode->bitdepth == 8) {
- out[i * 4 + 0] = r;
- out[i * 4 + 1] = g;
- out[i * 4 + 2] = b;
- out[i * 4 + 3] = a;
- } else {
- out[i * 8 + 0] = out[i * 8 + 1] = r;
- out[i * 8 + 2] = out[i * 8 + 3] = g;
- out[i * 8 + 4] = out[i * 8 + 5] = b;
- out[i * 8 + 6] = out[i * 8 + 7] = a;
- }
- }
-
- return 0; /*no error*/
-}
-
-/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/
-static void rgba16ToPixel(unsigned char* out, size_t i,
- const LodePNGColorMode* mode,
- unsigned short r, unsigned short g, unsigned short b, unsigned short a) {
- if(mode->colortype == LCT_GREY) {
- unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/
- out[i * 2 + 0] = (gray >> 8) & 255;
- out[i * 2 + 1] = gray & 255;
- } else if(mode->colortype == LCT_RGB) {
- out[i * 6 + 0] = (r >> 8) & 255;
- out[i * 6 + 1] = r & 255;
- out[i * 6 + 2] = (g >> 8) & 255;
- out[i * 6 + 3] = g & 255;
- out[i * 6 + 4] = (b >> 8) & 255;
- out[i * 6 + 5] = b & 255;
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/
- out[i * 4 + 0] = (gray >> 8) & 255;
- out[i * 4 + 1] = gray & 255;
- out[i * 4 + 2] = (a >> 8) & 255;
- out[i * 4 + 3] = a & 255;
- } else if(mode->colortype == LCT_RGBA) {
- out[i * 8 + 0] = (r >> 8) & 255;
- out[i * 8 + 1] = r & 255;
- out[i * 8 + 2] = (g >> 8) & 255;
- out[i * 8 + 3] = g & 255;
- out[i * 8 + 4] = (b >> 8) & 255;
- out[i * 8 + 5] = b & 255;
- out[i * 8 + 6] = (a >> 8) & 255;
- out[i * 8 + 7] = a & 255;
- }
-}
-
-/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/
-static void getPixelColorRGBA8(unsigned char* r, unsigned char* g,
- unsigned char* b, unsigned char* a,
- const unsigned char* in, size_t i,
- const LodePNGColorMode* mode) {
- if(mode->colortype == LCT_GREY) {
- if(mode->bitdepth == 8) {
- *r = *g = *b = in[i];
- if(mode->key_defined && *r == mode->key_r) *a = 0;
- else *a = 255;
- } else if(mode->bitdepth == 16) {
- *r = *g = *b = in[i * 2 + 0];
- if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
- else *a = 255;
- } else {
- unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
- size_t j = i * mode->bitdepth;
- unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
- *r = *g = *b = (value * 255) / highest;
- if(mode->key_defined && value == mode->key_r) *a = 0;
- else *a = 255;
- }
- } else if(mode->colortype == LCT_RGB) {
- if(mode->bitdepth == 8) {
- *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2];
- if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0;
- else *a = 255;
- } else {
- *r = in[i * 6 + 0];
- *g = in[i * 6 + 2];
- *b = in[i * 6 + 4];
- if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
- && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
- && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
- else *a = 255;
- }
- } else if(mode->colortype == LCT_PALETTE) {
- unsigned index;
- if(mode->bitdepth == 8) index = in[i];
- else {
- size_t j = i * mode->bitdepth;
- index = readBitsFromReversedStream(&j, in, mode->bitdepth);
- }
- /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
- *r = mode->palette[index * 4 + 0];
- *g = mode->palette[index * 4 + 1];
- *b = mode->palette[index * 4 + 2];
- *a = mode->palette[index * 4 + 3];
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- if(mode->bitdepth == 8) {
- *r = *g = *b = in[i * 2 + 0];
- *a = in[i * 2 + 1];
- } else {
- *r = *g = *b = in[i * 4 + 0];
- *a = in[i * 4 + 2];
- }
- } else if(mode->colortype == LCT_RGBA) {
- if(mode->bitdepth == 8) {
- *r = in[i * 4 + 0];
- *g = in[i * 4 + 1];
- *b = in[i * 4 + 2];
- *a = in[i * 4 + 3];
- } else {
- *r = in[i * 8 + 0];
- *g = in[i * 8 + 2];
- *b = in[i * 8 + 4];
- *a = in[i * 8 + 6];
- }
- }
-}
-
-/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color
-mode test cases, optimized to convert the colors much faster, when converting
-to the common case of RGBA with 8 bit per channel. buffer must be RGBA with
-enough memory.*/
-static void getPixelColorsRGBA8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels,
- const unsigned char* LODEPNG_RESTRICT in,
- const LodePNGColorMode* mode) {
- unsigned num_channels = 4;
- size_t i;
- if(mode->colortype == LCT_GREY) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i];
- buffer[3] = 255;
- }
- if(mode->key_defined) {
- buffer -= numpixels * num_channels;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- if(buffer[0] == mode->key_r) buffer[3] = 0;
- }
- }
- } else if(mode->bitdepth == 16) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 2];
- buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255;
- }
- } else {
- unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
- size_t j = 0;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
- buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest;
- buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255;
- }
- }
- } else if(mode->colortype == LCT_RGB) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- lodepng_memcpy(buffer, &in[i * 3], 3);
- buffer[3] = 255;
- }
- if(mode->key_defined) {
- buffer -= numpixels * num_channels;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- if(buffer[0] == mode->key_r && buffer[1]== mode->key_g && buffer[2] == mode->key_b) buffer[3] = 0;
- }
- }
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = in[i * 6 + 0];
- buffer[1] = in[i * 6 + 2];
- buffer[2] = in[i * 6 + 4];
- buffer[3] = mode->key_defined
- && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
- && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
- && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255;
- }
- }
- } else if(mode->colortype == LCT_PALETTE) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned index = in[i];
- /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
- lodepng_memcpy(buffer, &mode->palette[index * 4], 4);
- }
- } else {
- size_t j = 0;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth);
- /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
- lodepng_memcpy(buffer, &mode->palette[index * 4], 4);
- }
- }
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0];
- buffer[3] = in[i * 2 + 1];
- }
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0];
- buffer[3] = in[i * 4 + 2];
- }
- }
- } else if(mode->colortype == LCT_RGBA) {
- if(mode->bitdepth == 8) {
- lodepng_memcpy(buffer, in, numpixels * 4);
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = in[i * 8 + 0];
- buffer[1] = in[i * 8 + 2];
- buffer[2] = in[i * 8 + 4];
- buffer[3] = in[i * 8 + 6];
- }
- }
- }
-}
-
-/*Similar to getPixelColorsRGBA8, but with 3-channel RGB output.*/
-static void getPixelColorsRGB8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels,
- const unsigned char* LODEPNG_RESTRICT in,
- const LodePNGColorMode* mode) {
- const unsigned num_channels = 3;
- size_t i;
- if(mode->colortype == LCT_GREY) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i];
- }
- } else if(mode->bitdepth == 16) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 2];
- }
- } else {
- unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
- size_t j = 0;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
- buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest;
- }
- }
- } else if(mode->colortype == LCT_RGB) {
- if(mode->bitdepth == 8) {
- lodepng_memcpy(buffer, in, numpixels * 3);
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = in[i * 6 + 0];
- buffer[1] = in[i * 6 + 2];
- buffer[2] = in[i * 6 + 4];
- }
- }
- } else if(mode->colortype == LCT_PALETTE) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned index = in[i];
- /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
- lodepng_memcpy(buffer, &mode->palette[index * 4], 3);
- }
- } else {
- size_t j = 0;
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth);
- /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
- lodepng_memcpy(buffer, &mode->palette[index * 4], 3);
- }
- }
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0];
- }
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0];
- }
- }
- } else if(mode->colortype == LCT_RGBA) {
- if(mode->bitdepth == 8) {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- lodepng_memcpy(buffer, &in[i * 4], 3);
- }
- } else {
- for(i = 0; i != numpixels; ++i, buffer += num_channels) {
- buffer[0] = in[i * 8 + 0];
- buffer[1] = in[i * 8 + 2];
- buffer[2] = in[i * 8 + 4];
- }
- }
- }
-}
-
-/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with
-given color type, but the given color type must be 16-bit itself.*/
-static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a,
- const unsigned char* in, size_t i, const LodePNGColorMode* mode) {
- if(mode->colortype == LCT_GREY) {
- *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1];
- if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
- else *a = 65535;
- } else if(mode->colortype == LCT_RGB) {
- *r = 256u * in[i * 6 + 0] + in[i * 6 + 1];
- *g = 256u * in[i * 6 + 2] + in[i * 6 + 3];
- *b = 256u * in[i * 6 + 4] + in[i * 6 + 5];
- if(mode->key_defined
- && 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
- && 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
- && 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
- else *a = 65535;
- } else if(mode->colortype == LCT_GREY_ALPHA) {
- *r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1];
- *a = 256u * in[i * 4 + 2] + in[i * 4 + 3];
- } else if(mode->colortype == LCT_RGBA) {
- *r = 256u * in[i * 8 + 0] + in[i * 8 + 1];
- *g = 256u * in[i * 8 + 2] + in[i * 8 + 3];
- *b = 256u * in[i * 8 + 4] + in[i * 8 + 5];
- *a = 256u * in[i * 8 + 6] + in[i * 8 + 7];
- }
-}
-
-unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
- const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
- unsigned w, unsigned h) {
- size_t i;
- ColorTree tree;
- size_t numpixels = (size_t)w * (size_t)h;
- unsigned error = 0;
-
- if(mode_in->colortype == LCT_PALETTE && !mode_in->palette) {
- return 107; /* error: must provide palette if input mode is palette */
- }
-
- if(lodepng_color_mode_equal(mode_out, mode_in)) {
- size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
- lodepng_memcpy(out, in, numbytes);
- return 0;
- }
-
- if(mode_out->colortype == LCT_PALETTE) {
- size_t palettesize = mode_out->palettesize;
- const unsigned char* palette = mode_out->palette;
- size_t palsize = (size_t)1u << mode_out->bitdepth;
- /*if the user specified output palette but did not give the values, assume
- they want the values of the input color type (assuming that one is palette).
- Note that we never create a new palette ourselves.*/
- if(palettesize == 0) {
- palettesize = mode_in->palettesize;
- palette = mode_in->palette;
- /*if the input was also palette with same bitdepth, then the color types are also
- equal, so copy literally. This to preserve the exact indices that were in the PNG
- even in case there are duplicate colors in the palette.*/
- if(mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) {
- size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
- lodepng_memcpy(out, in, numbytes);
- return 0;
- }
- }
- if(palettesize < palsize) palsize = palettesize;
- color_tree_init(&tree);
- for(i = 0; i != palsize; ++i) {
- const unsigned char* p = &palette[i * 4];
- error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i);
- if(error) break;
- }
- }
-
- if(!error) {
- if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) {
- for(i = 0; i != numpixels; ++i) {
- unsigned short r = 0, g = 0, b = 0, a = 0;
- getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
- rgba16ToPixel(out, i, mode_out, r, g, b, a);
- }
- } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) {
- getPixelColorsRGBA8(out, numpixels, in, mode_in);
- } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) {
- getPixelColorsRGB8(out, numpixels, in, mode_in);
- } else {
- unsigned char r = 0, g = 0, b = 0, a = 0;
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
- error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a);
- if(error) break;
- }
- }
- }
-
- if(mode_out->colortype == LCT_PALETTE) {
- color_tree_cleanup(&tree);
- }
-
- return error;
-}
-
-
-/* Converts a single rgb color without alpha from one type to another, color bits truncated to
-their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow
-function, do not use to process all pixels of an image. Alpha channel not supported on purpose:
-this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the
-specification it looks like bKGD should ignore the alpha values of the palette since it can use
-any palette index but doesn't have an alpha channel. Idem with ignoring color key. */
-unsigned lodepng_convert_rgb(
- unsigned* r_out, unsigned* g_out, unsigned* b_out,
- unsigned r_in, unsigned g_in, unsigned b_in,
- const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in) {
- unsigned r = 0, g = 0, b = 0;
- unsigned mul = 65535 / ((1u << mode_in->bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/
- unsigned shift = 16 - mode_out->bitdepth;
-
- if(mode_in->colortype == LCT_GREY || mode_in->colortype == LCT_GREY_ALPHA) {
- r = g = b = r_in * mul;
- } else if(mode_in->colortype == LCT_RGB || mode_in->colortype == LCT_RGBA) {
- r = r_in * mul;
- g = g_in * mul;
- b = b_in * mul;
- } else if(mode_in->colortype == LCT_PALETTE) {
- if(r_in >= mode_in->palettesize) return 82;
- r = mode_in->palette[r_in * 4 + 0] * 257u;
- g = mode_in->palette[r_in * 4 + 1] * 257u;
- b = mode_in->palette[r_in * 4 + 2] * 257u;
- } else {
- return 31;
- }
-
- /* now convert to output format */
- if(mode_out->colortype == LCT_GREY || mode_out->colortype == LCT_GREY_ALPHA) {
- *r_out = r >> shift ;
- } else if(mode_out->colortype == LCT_RGB || mode_out->colortype == LCT_RGBA) {
- *r_out = r >> shift ;
- *g_out = g >> shift ;
- *b_out = b >> shift ;
- } else if(mode_out->colortype == LCT_PALETTE) {
- unsigned i;
- /* a 16-bit color cannot be in the palette */
- if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82;
- for(i = 0; i < mode_out->palettesize; i++) {
- unsigned j = i * 4;
- if((r >> 8) == mode_out->palette[j + 0] && (g >> 8) == mode_out->palette[j + 1] &&
- (b >> 8) == mode_out->palette[j + 2]) {
- *r_out = i;
- return 0;
- }
- }
- return 82;
- } else {
- return 31;
- }
-
- return 0;
-}
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-void lodepng_color_stats_init(LodePNGColorStats* stats) {
- /*stats*/
- stats->colored = 0;
- stats->key = 0;
- stats->key_r = stats->key_g = stats->key_b = 0;
- stats->alpha = 0;
- stats->numcolors = 0;
- stats->bits = 1;
- stats->numpixels = 0;
- /*settings*/
- stats->allow_palette = 1;
- stats->allow_greyscale = 1;
-}
-
-/*function used for debug purposes with C++*/
-/*void printColorStats(LodePNGColorStats* p) {
- std::cout << "colored: " << (int)p->colored << ", ";
- std::cout << "key: " << (int)p->key << ", ";
- std::cout << "key_r: " << (int)p->key_r << ", ";
- std::cout << "key_g: " << (int)p->key_g << ", ";
- std::cout << "key_b: " << (int)p->key_b << ", ";
- std::cout << "alpha: " << (int)p->alpha << ", ";
- std::cout << "numcolors: " << (int)p->numcolors << ", ";
- std::cout << "bits: " << (int)p->bits << std::endl;
-}*/
-
-/*Returns how many bits needed to represent given value (max 8 bit)*/
-static unsigned getValueRequiredBits(unsigned char value) {
- if(value == 0 || value == 255) return 1;
- /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/
- if(value % 17 == 0) return value % 85 == 0 ? 2 : 4;
- return 8;
-}
-
-/*stats must already have been inited. */
-unsigned lodepng_compute_color_stats(LodePNGColorStats* stats,
- const unsigned char* in, unsigned w, unsigned h,
- const LodePNGColorMode* mode_in) {
- size_t i;
- ColorTree tree;
- size_t numpixels = (size_t)w * (size_t)h;
- unsigned error = 0;
-
- /* mark things as done already if it would be impossible to have a more expensive case */
- unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0;
- unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1;
- unsigned numcolors_done = 0;
- unsigned bpp = lodepng_get_bpp(mode_in);
- unsigned bits_done = (stats->bits == 1 && bpp == 1) ? 1 : 0;
- unsigned sixteen = 0; /* whether the input image is 16 bit */
- unsigned maxnumcolors = 257;
- if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, stats->numcolors + (1u << bpp));
-
- stats->numpixels += numpixels;
-
- /*if palette not allowed, no need to compute numcolors*/
- if(!stats->allow_palette) numcolors_done = 1;
-
- color_tree_init(&tree);
-
- /*If the stats was already filled in from previous data, fill its palette in tree
- and mark things as done already if we know they are the most expensive case already*/
- if(stats->alpha) alpha_done = 1;
- if(stats->colored) colored_done = 1;
- if(stats->bits == 16) numcolors_done = 1;
- if(stats->bits >= bpp) bits_done = 1;
- if(stats->numcolors >= maxnumcolors) numcolors_done = 1;
-
- if(!numcolors_done) {
- for(i = 0; i < stats->numcolors; i++) {
- const unsigned char* color = &stats->palette[i * 4];
- error = color_tree_add(&tree, color[0], color[1], color[2], color[3], i);
- if(error) goto cleanup;
- }
- }
-
- /*Check if the 16-bit input is truly 16-bit*/
- if(mode_in->bitdepth == 16 && !sixteen) {
- unsigned short r = 0, g = 0, b = 0, a = 0;
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
- if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) ||
- (b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ {
- stats->bits = 16;
- sixteen = 1;
- bits_done = 1;
- numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/
- break;
- }
- }
- }
-
- if(sixteen) {
- unsigned short r = 0, g = 0, b = 0, a = 0;
-
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
-
- if(!colored_done && (r != g || r != b)) {
- stats->colored = 1;
- colored_done = 1;
- }
-
- if(!alpha_done) {
- unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b);
- if(a != 65535 && (a != 0 || (stats->key && !matchkey))) {
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- } else if(a == 0 && !stats->alpha && !stats->key) {
- stats->key = 1;
- stats->key_r = r;
- stats->key_g = g;
- stats->key_b = b;
- } else if(a == 65535 && stats->key && matchkey) {
- /* Color key cannot be used if an opaque pixel also has that RGB color. */
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- }
- }
- if(alpha_done && numcolors_done && colored_done && bits_done) break;
- }
-
- if(stats->key && !stats->alpha) {
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
- if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) {
- /* Color key cannot be used if an opaque pixel also has that RGB color. */
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- }
- }
- }
- } else /* < 16-bit */ {
- unsigned char r = 0, g = 0, b = 0, a = 0;
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
-
- if(!bits_done && stats->bits < 8) {
- /*only r is checked, < 8 bits is only relevant for grayscale*/
- unsigned bits = getValueRequiredBits(r);
- if(bits > stats->bits) stats->bits = bits;
- }
- bits_done = (stats->bits >= bpp);
-
- if(!colored_done && (r != g || r != b)) {
- stats->colored = 1;
- colored_done = 1;
- if(stats->bits < 8) stats->bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/
- }
-
- if(!alpha_done) {
- unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b);
- if(a != 255 && (a != 0 || (stats->key && !matchkey))) {
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
- } else if(a == 0 && !stats->alpha && !stats->key) {
- stats->key = 1;
- stats->key_r = r;
- stats->key_g = g;
- stats->key_b = b;
- } else if(a == 255 && stats->key && matchkey) {
- /* Color key cannot be used if an opaque pixel also has that RGB color. */
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
- }
- }
-
- if(!numcolors_done) {
- if(!color_tree_has(&tree, r, g, b, a)) {
- error = color_tree_add(&tree, r, g, b, a, stats->numcolors);
- if(error) goto cleanup;
- if(stats->numcolors < 256) {
- unsigned char* p = stats->palette;
- unsigned n = stats->numcolors;
- p[n * 4 + 0] = r;
- p[n * 4 + 1] = g;
- p[n * 4 + 2] = b;
- p[n * 4 + 3] = a;
- }
- ++stats->numcolors;
- numcolors_done = stats->numcolors >= maxnumcolors;
- }
- }
-
- if(alpha_done && numcolors_done && colored_done && bits_done) break;
- }
-
- if(stats->key && !stats->alpha) {
- for(i = 0; i != numpixels; ++i) {
- getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
- if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) {
- /* Color key cannot be used if an opaque pixel also has that RGB color. */
- stats->alpha = 1;
- stats->key = 0;
- alpha_done = 1;
- if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
- }
- }
- }
-
- /*make the stats's key always 16-bit for consistency - repeat each byte twice*/
- stats->key_r += (stats->key_r << 8);
- stats->key_g += (stats->key_g << 8);
- stats->key_b += (stats->key_b << 8);
- }
-
-cleanup:
- color_tree_cleanup(&tree);
- return error;
-}
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-/*Adds a single color to the color stats. The stats must already have been inited. The color must be given as 16-bit
-(with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for
-all pixels of an image but only for a few additional values. */
-static unsigned lodepng_color_stats_add(LodePNGColorStats* stats,
- unsigned r, unsigned g, unsigned b, unsigned a) {
- unsigned error = 0;
- unsigned char image[8];
- LodePNGColorMode mode;
- lodepng_color_mode_init(&mode);
- image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g;
- image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a;
- mode.bitdepth = 16;
- mode.colortype = LCT_RGBA;
- error = lodepng_compute_color_stats(stats, image, 1, 1, &mode);
- lodepng_color_mode_cleanup(&mode);
- return error;
-}
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-/*Computes a minimal PNG color model that can contain all colors as indicated by the stats.
-The stats should be computed with lodepng_compute_color_stats.
-mode_in is raw color profile of the image the stats were computed on, to copy palette order from when relevant.
-Minimal PNG color model means the color type and bit depth that gives smallest amount of bits in the output image,
-e.g. gray if only grayscale pixels, palette if less than 256 colors, color key if only single transparent color, ...
-This is used if auto_convert is enabled (it is by default).
-*/
-static unsigned auto_choose_color(LodePNGColorMode* mode_out,
- const LodePNGColorMode* mode_in,
- const LodePNGColorStats* stats) {
- unsigned error = 0;
- unsigned palettebits;
- size_t i, n;
- size_t numpixels = stats->numpixels;
- unsigned palette_ok, gray_ok;
-
- unsigned alpha = stats->alpha;
- unsigned key = stats->key;
- unsigned bits = stats->bits;
-
- mode_out->key_defined = 0;
-
- if(key && numpixels <= 16) {
- alpha = 1; /*too few pixels to justify tRNS chunk overhead*/
- key = 0;
- if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
- }
-
- gray_ok = !stats->colored;
- if(!stats->allow_greyscale) gray_ok = 0;
- if(!gray_ok && bits < 8) bits = 8;
-
- n = stats->numcolors;
- palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8));
- palette_ok = n <= 256 && bits <= 8 && n != 0; /*n==0 means likely numcolors wasn't computed*/
- if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/
- if(gray_ok && !alpha && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/
- if(!stats->allow_palette) palette_ok = 0;
-
- if(palette_ok) {
- const unsigned char* p = stats->palette;
- lodepng_palette_clear(mode_out); /*remove potential earlier palette*/
- for(i = 0; i != stats->numcolors; ++i) {
- error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]);
- if(error) break;
- }
-
- mode_out->colortype = LCT_PALETTE;
- mode_out->bitdepth = palettebits;
-
- if(mode_in->colortype == LCT_PALETTE && mode_in->palettesize >= mode_out->palettesize
- && mode_in->bitdepth == mode_out->bitdepth) {
- /*If input should have same palette colors, keep original to preserve its order and prevent conversion*/
- lodepng_color_mode_cleanup(mode_out);
- lodepng_color_mode_copy(mode_out, mode_in);
- }
- } else /*8-bit or 16-bit per channel*/ {
- mode_out->bitdepth = bits;
- mode_out->colortype = alpha ? (gray_ok ? LCT_GREY_ALPHA : LCT_RGBA)
- : (gray_ok ? LCT_GREY : LCT_RGB);
- if(key) {
- unsigned mask = (1u << mode_out->bitdepth) - 1u; /*stats always uses 16-bit, mask converts it*/
- mode_out->key_r = stats->key_r & mask;
- mode_out->key_g = stats->key_g & mask;
- mode_out->key_b = stats->key_b & mask;
- mode_out->key_defined = 1;
- }
- }
-
- return error;
-}
-
-#endif /* #ifdef LODEPNG_COMPILE_ENCODER */
-
-/*
-Paeth predictor, used by PNG filter type 4
-The parameters are of type short, but should come from unsigned chars, the shorts
-are only needed to make the paeth calculation correct.
-*/
-static unsigned char paethPredictor(short a, short b, short c) {
- short pa = LODEPNG_ABS(b - c);
- short pb = LODEPNG_ABS(a - c);
- short pc = LODEPNG_ABS(a + b - c - c);
- /* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */
- if(pb < pa) { a = b; pa = pb; }
- return (pc < pa) ? c : a;
-}
-
-/*shared values used by multiple Adam7 related functions*/
-
-static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/
-static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/
-static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/
-static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/
-
-/*
-Outputs various dimensions and positions in the image related to the Adam7 reduced images.
-passw: output containing the width of the 7 passes
-passh: output containing the height of the 7 passes
-filter_passstart: output containing the index of the start and end of each
- reduced image with filter bytes
-padded_passstart output containing the index of the start and end of each
- reduced image when without filter bytes but with padded scanlines
-passstart: output containing the index of the start and end of each reduced
- image without padding between scanlines, but still padding between the images
-w, h: width and height of non-interlaced image
-bpp: bits per pixel
-"padded" is only relevant if bpp is less than 8 and a scanline or image does not
- end at a full byte
-*/
-static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8],
- size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) {
- /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/
- unsigned i;
-
- /*calculate width and height in pixels of each pass*/
- for(i = 0; i != 7; ++i) {
- passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i];
- passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i];
- if(passw[i] == 0) passh[i] = 0;
- if(passh[i] == 0) passw[i] = 0;
- }
-
- filter_passstart[0] = padded_passstart[0] = passstart[0] = 0;
- for(i = 0; i != 7; ++i) {
- /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/
- filter_passstart[i + 1] = filter_passstart[i]
- + ((passw[i] && passh[i]) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0);
- /*bits padded if needed to fill full byte at end of each scanline*/
- padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u);
- /*only padded at end of reduced image*/
- passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u;
- }
-}
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / PNG Decoder / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-/*read the information from the header and store it in the LodePNGInfo. return value is error*/
-unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state,
- const unsigned char* in, size_t insize) {
- unsigned width, height;
- LodePNGInfo* info = &state->info_png;
- if(insize == 0 || in == 0) {
- CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/
- }
- if(insize < 33) {
- CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/
- }
-
- /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/
- /* TODO: remove this. One should use a new LodePNGState for new sessions */
- lodepng_info_cleanup(info);
- lodepng_info_init(info);
-
- if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71
- || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) {
- CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/
- }
- if(lodepng_chunk_length(in + 8) != 13) {
- CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/
- }
- if(!lodepng_chunk_type_equals(in + 8, "IHDR")) {
- CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/
- }
-
- /*read the values given in the header*/
- width = lodepng_read32bitInt(&in[16]);
- height = lodepng_read32bitInt(&in[20]);
- /*TODO: remove the undocumented feature that allows to give null pointers to width or height*/
- if(w) *w = width;
- if(h) *h = height;
- info->color.bitdepth = in[24];
- info->color.colortype = (LodePNGColorType)in[25];
- info->compression_method = in[26];
- info->filter_method = in[27];
- info->interlace_method = in[28];
-
- /*errors returned only after the parsing so other values are still output*/
-
- /*error: invalid image size*/
- if(width == 0 || height == 0) CERROR_RETURN_ERROR(state->error, 93);
- /*error: invalid colortype or bitdepth combination*/
- state->error = checkColorValidity(info->color.colortype, info->color.bitdepth);
- if(state->error) return state->error;
- /*error: only compression method 0 is allowed in the specification*/
- if(info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32);
- /*error: only filter method 0 is allowed in the specification*/
- if(info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33);
- /*error: only interlace methods 0 and 1 exist in the specification*/
- if(info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34);
-
- if(!state->decoder.ignore_crc) {
- unsigned CRC = lodepng_read32bitInt(&in[29]);
- unsigned checksum = lodepng_crc32(&in[12], 17);
- if(CRC != checksum) {
- CERROR_RETURN_ERROR(state->error, 57); /*invalid CRC*/
- }
- }
-
- return state->error;
-}
-
-static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon,
- size_t bytewidth, unsigned char filterType, size_t length) {
- /*
- For PNG filter method 0
- unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte,
- the filter works byte per byte (bytewidth = 1)
- precon is the previous unfiltered scanline, recon the result, scanline the current one
- the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead
- recon and scanline MAY be the same memory address! precon must be disjoint.
- */
-
- size_t i;
- switch(filterType) {
- case 0:
- for(i = 0; i != length; ++i) recon[i] = scanline[i];
- break;
- case 1:
- for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
- for(i = bytewidth; i < length; ++i) recon[i] = scanline[i] + recon[i - bytewidth];
- break;
- case 2:
- if(precon) {
- for(i = 0; i != length; ++i) recon[i] = scanline[i] + precon[i];
- } else {
- for(i = 0; i != length; ++i) recon[i] = scanline[i];
- }
- break;
- case 3:
- if(precon) {
- for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i] + (precon[i] >> 1u);
- for(i = bytewidth; i < length; ++i) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) >> 1u);
- } else {
- for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
- for(i = bytewidth; i < length; ++i) recon[i] = scanline[i] + (recon[i - bytewidth] >> 1u);
- }
- break;
- case 4:
- if(precon) {
- for(i = 0; i != bytewidth; ++i) {
- recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/
- }
-
- /* Unroll independent paths of the paeth predictor. A 6x and 8x version would also be possible but that
- adds too much code. Whether this actually speeds anything up at all depends on compiler and settings. */
- if(bytewidth >= 4) {
- for(; i + 3 < length; i += 4) {
- size_t j = i - bytewidth;
- unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3];
- unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3];
- unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3];
- unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2], q3 = precon[j + 3];
- recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
- recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
- recon[i + 2] = s2 + paethPredictor(r2, p2, q2);
- recon[i + 3] = s3 + paethPredictor(r3, p3, q3);
- }
- } else if(bytewidth >= 3) {
- for(; i + 2 < length; i += 3) {
- size_t j = i - bytewidth;
- unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2];
- unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2];
- unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2];
- unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2];
- recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
- recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
- recon[i + 2] = s2 + paethPredictor(r2, p2, q2);
- }
- } else if(bytewidth >= 2) {
- for(; i + 1 < length; i += 2) {
- size_t j = i - bytewidth;
- unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1];
- unsigned char r0 = recon[j + 0], r1 = recon[j + 1];
- unsigned char p0 = precon[i + 0], p1 = precon[i + 1];
- unsigned char q0 = precon[j + 0], q1 = precon[j + 1];
- recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
- recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
- }
- }
-
- for(; i != length; ++i) {
- recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth]));
- }
- } else {
- for(i = 0; i != bytewidth; ++i) {
- recon[i] = scanline[i];
- }
- for(i = bytewidth; i < length; ++i) {
- /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/
- recon[i] = (scanline[i] + recon[i - bytewidth]);
- }
- }
- break;
- default: return 36; /*error: invalid filter type given*/
- }
- return 0;
-}
-
-static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
- /*
- For PNG filter method 0
- this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times)
- out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline
- w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
- in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
- */
-
- unsigned y;
- unsigned char* prevline = 0;
-
- /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
- size_t bytewidth = (bpp + 7u) / 8u;
- /*the width of a scanline in bytes, not including the filter type*/
- size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;
-
- for(y = 0; y < h; ++y) {
- size_t outindex = linebytes * y;
- size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
- unsigned char filterType = in[inindex];
-
- CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes));
-
- prevline = &out[outindex];
- }
-
- return 0;
-}
-
-/*
-in: Adam7 interlaced image, with no padding bits between scanlines, but between
- reduced images so that each reduced image starts at a byte.
-out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h
-bpp: bits per pixel
-out has the following size in bits: w * h * bpp.
-in is possibly bigger due to padding bits between reduced images.
-out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation
-(because that's likely a little bit faster)
-NOTE: comments about padding bits are only relevant if bpp < 8
-*/
-static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
- unsigned passw[7], passh[7];
- size_t filter_passstart[8], padded_passstart[8], passstart[8];
- unsigned i;
-
- Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
-
- if(bpp >= 8) {
- for(i = 0; i != 7; ++i) {
- unsigned x, y, b;
- size_t bytewidth = bpp / 8u;
- for(y = 0; y < passh[i]; ++y)
- for(x = 0; x < passw[i]; ++x) {
- size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth;
- size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w
- + ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth;
- for(b = 0; b < bytewidth; ++b) {
- out[pixeloutstart + b] = in[pixelinstart + b];
- }
- }
- }
- } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
- for(i = 0; i != 7; ++i) {
- unsigned x, y, b;
- unsigned ilinebits = bpp * passw[i];
- unsigned olinebits = bpp * w;
- size_t obp, ibp; /*bit pointers (for out and in buffer)*/
- for(y = 0; y < passh[i]; ++y)
- for(x = 0; x < passw[i]; ++x) {
- ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
- obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp;
- for(b = 0; b < bpp; ++b) {
- unsigned char bit = readBitFromReversedStream(&ibp, in);
- setBitOfReversedStream(&obp, out, bit);
- }
- }
- }
- }
-}
-
-static void removePaddingBits(unsigned char* out, const unsigned char* in,
- size_t olinebits, size_t ilinebits, unsigned h) {
- /*
- After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need
- to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers
- for the Adam7 code, the color convert code and the output to the user.
- in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must
- have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits
- also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7
- only useful if (ilinebits - olinebits) is a value in the range 1..7
- */
- unsigned y;
- size_t diff = ilinebits - olinebits;
- size_t ibp = 0, obp = 0; /*input and output bit pointers*/
- for(y = 0; y < h; ++y) {
- size_t x;
- for(x = 0; x < olinebits; ++x) {
- unsigned char bit = readBitFromReversedStream(&ibp, in);
- setBitOfReversedStream(&obp, out, bit);
- }
- ibp += diff;
- }
-}
-
-/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from
-the IDAT chunks (with filter index bytes and possible padding bits)
-return value is error*/
-static unsigned postProcessScanlines(unsigned char* out, unsigned char* in,
- unsigned w, unsigned h, const LodePNGInfo* info_png) {
- /*
- This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype.
- Steps:
- *) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8)
- *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
- NOTE: the in buffer will be overwritten with intermediate data!
- */
- unsigned bpp = lodepng_get_bpp(&info_png->color);
- if(bpp == 0) return 31; /*error: invalid colortype*/
-
- if(info_png->interlace_method == 0) {
- if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
- CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp));
- removePaddingBits(out, in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h);
- }
- /*we can immediately filter into the out buffer, no other steps needed*/
- else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp));
- } else /*interlace_method is 1 (Adam7)*/ {
- unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
- unsigned i;
-
- Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
-
- for(i = 0; i != 7; ++i) {
- CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp));
- /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline,
- move bytes instead of bits or move not at all*/
- if(bpp < 8) {
- /*remove padding bits in scanlines; after this there still may be padding
- bits between the different reduced images: each reduced image still starts nicely at a byte*/
- removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp,
- ((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]);
- }
- }
-
- Adam7_deinterlace(out, in, w, h, bpp);
- }
-
- return 0;
-}
-
-static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) {
- unsigned pos = 0, i;
- color->palettesize = chunkLength / 3u;
- if(color->palettesize == 0 || color->palettesize > 256) return 38; /*error: palette too small or big*/
- lodepng_color_mode_alloc_palette(color);
- if(!color->palette && color->palettesize) {
- color->palettesize = 0;
- return 83; /*alloc fail*/
- }
-
- for(i = 0; i != color->palettesize; ++i) {
- color->palette[4 * i + 0] = data[pos++]; /*R*/
- color->palette[4 * i + 1] = data[pos++]; /*G*/
- color->palette[4 * i + 2] = data[pos++]; /*B*/
- color->palette[4 * i + 3] = 255; /*alpha*/
- }
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) {
- unsigned i;
- if(color->colortype == LCT_PALETTE) {
- /*error: more alpha values given than there are palette entries*/
- if(chunkLength > color->palettesize) return 39;
-
- for(i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i];
- } else if(color->colortype == LCT_GREY) {
- /*error: this chunk must be 2 bytes for grayscale image*/
- if(chunkLength != 2) return 30;
-
- color->key_defined = 1;
- color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1];
- } else if(color->colortype == LCT_RGB) {
- /*error: this chunk must be 6 bytes for RGB image*/
- if(chunkLength != 6) return 41;
-
- color->key_defined = 1;
- color->key_r = 256u * data[0] + data[1];
- color->key_g = 256u * data[2] + data[3];
- color->key_b = 256u * data[4] + data[5];
- }
- else return 42; /*error: tRNS chunk not allowed for other color models*/
-
- return 0; /* OK */
-}
-
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-/*background color chunk (bKGD)*/
-static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(info->color.colortype == LCT_PALETTE) {
- /*error: this chunk must be 1 byte for indexed color image*/
- if(chunkLength != 1) return 43;
-
- /*error: invalid palette index, or maybe this chunk appeared before PLTE*/
- if(data[0] >= info->color.palettesize) return 103;
-
- info->background_defined = 1;
- info->background_r = info->background_g = info->background_b = data[0];
- } else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) {
- /*error: this chunk must be 2 bytes for grayscale image*/
- if(chunkLength != 2) return 44;
-
- /*the values are truncated to bitdepth in the PNG file*/
- info->background_defined = 1;
- info->background_r = info->background_g = info->background_b = 256u * data[0] + data[1];
- } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) {
- /*error: this chunk must be 6 bytes for grayscale image*/
- if(chunkLength != 6) return 45;
-
- /*the values are truncated to bitdepth in the PNG file*/
- info->background_defined = 1;
- info->background_r = 256u * data[0] + data[1];
- info->background_g = 256u * data[2] + data[3];
- info->background_b = 256u * data[4] + data[5];
- }
-
- return 0; /* OK */
-}
-
-/*text chunk (tEXt)*/
-static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- unsigned error = 0;
- char *key = 0, *str = 0;
-
- while(!error) /*not really a while loop, only used to break on error*/ {
- unsigned length, string2_begin;
-
- length = 0;
- while(length < chunkLength && data[length] != 0) ++length;
- /*even though it's not allowed by the standard, no error is thrown if
- there's no null termination char, if the text is empty*/
- if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
-
- key = (char*)lodepng_malloc(length + 1);
- if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(key, data, length);
- key[length] = 0;
-
- string2_begin = length + 1; /*skip keyword null terminator*/
-
- length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin);
- str = (char*)lodepng_malloc(length + 1);
- if(!str) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(str, data + string2_begin, length);
- str[length] = 0;
-
- error = lodepng_add_text(info, key, str);
-
- break;
- }
-
- lodepng_free(key);
- lodepng_free(str);
-
- return error;
-}
-
-/*compressed text chunk (zTXt)*/
-static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
- const unsigned char* data, size_t chunkLength) {
- unsigned error = 0;
-
- /*copy the object to change parameters in it*/
- LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
-
- unsigned length, string2_begin;
- char *key = 0;
- unsigned char* str = 0;
- size_t size = 0;
-
- while(!error) /*not really a while loop, only used to break on error*/ {
- for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
- if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
- if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
-
- key = (char*)lodepng_malloc(length + 1);
- if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(key, data, length);
- key[length] = 0;
-
- if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
-
- string2_begin = length + 2;
- if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
-
- length = (unsigned)chunkLength - string2_begin;
- zlibsettings.max_output_size = decoder->max_text_size;
- /*will fail if zlib error, e.g. if length is too small*/
- error = zlib_decompress(&str, &size, 0, &data[string2_begin],
- length, &zlibsettings);
- /*error: compressed text larger than decoder->max_text_size*/
- if(error && size > zlibsettings.max_output_size) error = 112;
- if(error) break;
- error = lodepng_add_text_sized(info, key, (char*)str, size);
- break;
- }
-
- lodepng_free(key);
- lodepng_free(str);
-
- return error;
-}
-
-/*international text chunk (iTXt)*/
-static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
- const unsigned char* data, size_t chunkLength) {
- unsigned error = 0;
- unsigned i;
-
- /*copy the object to change parameters in it*/
- LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
-
- unsigned length, begin, compressed;
- char *key = 0, *langtag = 0, *transkey = 0;
-
- while(!error) /*not really a while loop, only used to break on error*/ {
- /*Quick check if the chunk length isn't too small. Even without check
- it'd still fail with other error checks below if it's too short. This just gives a different error code.*/
- if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/
-
- /*read the key*/
- for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
- if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/
- if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
-
- key = (char*)lodepng_malloc(length + 1);
- if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(key, data, length);
- key[length] = 0;
-
- /*read the compression method*/
- compressed = data[length + 1];
- if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
-
- /*even though it's not allowed by the standard, no error is thrown if
- there's no null termination char, if the text is empty for the next 3 texts*/
-
- /*read the langtag*/
- begin = length + 3;
- length = 0;
- for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;
-
- langtag = (char*)lodepng_malloc(length + 1);
- if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(langtag, data + begin, length);
- langtag[length] = 0;
-
- /*read the transkey*/
- begin += length + 1;
- length = 0;
- for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;
-
- transkey = (char*)lodepng_malloc(length + 1);
- if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/
-
- lodepng_memcpy(transkey, data + begin, length);
- transkey[length] = 0;
-
- /*read the actual text*/
- begin += length + 1;
-
- length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin;
-
- if(compressed) {
- unsigned char* str = 0;
- size_t size = 0;
- zlibsettings.max_output_size = decoder->max_text_size;
- /*will fail if zlib error, e.g. if length is too small*/
- error = zlib_decompress(&str, &size, 0, &data[begin],
- length, &zlibsettings);
- /*error: compressed text larger than decoder->max_text_size*/
- if(error && size > zlibsettings.max_output_size) error = 112;
- if(!error) error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)str, size);
- lodepng_free(str);
- } else {
- error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)(data + begin), length);
- }
-
- break;
- }
-
- lodepng_free(key);
- lodepng_free(langtag);
- lodepng_free(transkey);
-
- return error;
-}
-
-static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(chunkLength != 7) return 73; /*invalid tIME chunk size*/
-
- info->time_defined = 1;
- info->time.year = 256u * data[0] + data[1];
- info->time.month = data[2];
- info->time.day = data[3];
- info->time.hour = data[4];
- info->time.minute = data[5];
- info->time.second = data[6];
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/
-
- info->phys_defined = 1;
- info->phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];
- info->phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7];
- info->phys_unit = data[8];
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_gAMA(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/
-
- info->gama_defined = 1;
- info->gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_cHRM(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/
-
- info->chrm_defined = 1;
- info->chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3];
- info->chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7];
- info->chrm_red_x = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11];
- info->chrm_red_y = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15];
- info->chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19];
- info->chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23];
- info->chrm_blue_x = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27];
- info->chrm_blue_y = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31];
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_sRGB(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) {
- if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/
-
- info->srgb_defined = 1;
- info->srgb_intent = data[0];
-
- return 0; /* OK */
-}
-
-static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
- const unsigned char* data, size_t chunkLength) {
- unsigned error = 0;
- unsigned i;
- size_t size = 0;
- /*copy the object to change parameters in it*/
- LodePNGDecompressSettings zlibsettings = decoder->zlibsettings;
-
- unsigned length, string2_begin;
-
- info->iccp_defined = 1;
- if(info->iccp_name) lodepng_clear_icc(info);
-
- for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
- if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/
- if(length < 1 || length > 79) return 89; /*keyword too short or long*/
-
- info->iccp_name = (char*)lodepng_malloc(length + 1);
- if(!info->iccp_name) return 83; /*alloc fail*/
-
- info->iccp_name[length] = 0;
- for(i = 0; i != length; ++i) info->iccp_name[i] = (char)data[i];
-
- if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/
-
- string2_begin = length + 2;
- if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/
-
- length = (unsigned)chunkLength - string2_begin;
- zlibsettings.max_output_size = decoder->max_icc_size;
- error = zlib_decompress(&info->iccp_profile, &size, 0,
- &data[string2_begin],
- length, &zlibsettings);
- /*error: ICC profile larger than decoder->max_icc_size*/
- if(error && size > zlibsettings.max_output_size) error = 113;
- info->iccp_profile_size = size;
- if(!error && !info->iccp_profile_size) error = 100; /*invalid ICC profile size*/
- return error;
-}
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos,
- const unsigned char* in, size_t insize) {
- const unsigned char* chunk = in + pos;
- unsigned chunkLength;
- const unsigned char* data;
- unsigned unhandled = 0;
- unsigned error = 0;
-
- if(pos + 4 > insize) return 30;
- chunkLength = lodepng_chunk_length(chunk);
- if(chunkLength > 2147483647) return 63;
- data = lodepng_chunk_data_const(chunk);
- if(data + chunkLength + 4 > in + insize) return 30;
-
- if(lodepng_chunk_type_equals(chunk, "PLTE")) {
- error = readChunk_PLTE(&state->info_png.color, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
- error = readChunk_tRNS(&state->info_png.color, data, chunkLength);
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- } else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
- error = readChunk_bKGD(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
- error = readChunk_tEXt(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
- error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
- error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "tIME")) {
- error = readChunk_tIME(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
- error = readChunk_pHYs(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
- error = readChunk_gAMA(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
- error = readChunk_cHRM(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
- error = readChunk_sRGB(&state->info_png, data, chunkLength);
- } else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
- error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength);
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- } else {
- /* unhandled chunk is ok (is not an error) */
- unhandled = 1;
- }
-
- if(!error && !unhandled && !state->decoder.ignore_crc) {
- if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/
- }
-
- return error;
-}
-
-/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/
-static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h,
- LodePNGState* state,
- const unsigned char* in, size_t insize) {
- unsigned char IEND = 0;
- const unsigned char* chunk;
- unsigned char* idat; /*the data from idat chunks, zlib compressed*/
- size_t idatsize = 0;
- unsigned char* scanlines = 0;
- size_t scanlines_size = 0, expected_size = 0;
- size_t outsize = 0;
-
- /*for unknown chunk order*/
- unsigned unknown = 0;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-
- /* safe output values in case error happens */
- *out = 0;
- *w = *h = 0;
-
- state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/
- if(state->error) return;
-
- if(lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) {
- CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/
- }
-
- /*the input filesize is a safe upper bound for the sum of idat chunks size*/
- idat = (unsigned char*)lodepng_malloc(insize);
- if(!idat) CERROR_RETURN(state->error, 83); /*alloc fail*/
-
- chunk = &in[33]; /*first byte of the first chunk after the header*/
-
- /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk.
- IDAT data is put at the start of the in buffer*/
- while(!IEND && !state->error) {
- unsigned chunkLength;
- const unsigned char* data; /*the data in the chunk*/
-
- /*error: size of the in buffer too small to contain next chunk*/
- if((size_t)((chunk - in) + 12) > insize || chunk < in) {
- if(state->decoder.ignore_end) break; /*other errors may still happen though*/
- CERROR_BREAK(state->error, 30);
- }
-
- /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/
- chunkLength = lodepng_chunk_length(chunk);
- /*error: chunk length larger than the max PNG chunk size*/
- if(chunkLength > 2147483647) {
- if(state->decoder.ignore_end) break; /*other errors may still happen though*/
- CERROR_BREAK(state->error, 63);
- }
-
- if((size_t)((chunk - in) + chunkLength + 12) > insize || (chunk + chunkLength + 12) < in) {
- CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk*/
- }
-
- data = lodepng_chunk_data_const(chunk);
-
- unknown = 0;
-
- /*IDAT chunk, containing compressed image data*/
- if(lodepng_chunk_type_equals(chunk, "IDAT")) {
- size_t newsize;
- if(lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95);
- if(newsize > insize) CERROR_BREAK(state->error, 95);
- lodepng_memcpy(idat + idatsize, data, chunkLength);
- idatsize += chunkLength;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- critical_pos = 3;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- } else if(lodepng_chunk_type_equals(chunk, "IEND")) {
- /*IEND chunk*/
- IEND = 1;
- } else if(lodepng_chunk_type_equals(chunk, "PLTE")) {
- /*palette chunk (PLTE)*/
- state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength);
- if(state->error) break;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- critical_pos = 2;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- } else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
- /*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled
- in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that
- affects the alpha channel of pixels. */
- state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength);
- if(state->error) break;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*background color chunk (bKGD)*/
- } else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
- state->error = readChunk_bKGD(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
- /*text chunk (tEXt)*/
- if(state->decoder.read_text_chunks) {
- state->error = readChunk_tEXt(&state->info_png, data, chunkLength);
- if(state->error) break;
- }
- } else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
- /*compressed text chunk (zTXt)*/
- if(state->decoder.read_text_chunks) {
- state->error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength);
- if(state->error) break;
- }
- } else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
- /*international text chunk (iTXt)*/
- if(state->decoder.read_text_chunks) {
- state->error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength);
- if(state->error) break;
- }
- } else if(lodepng_chunk_type_equals(chunk, "tIME")) {
- state->error = readChunk_tIME(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
- state->error = readChunk_pHYs(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
- state->error = readChunk_gAMA(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
- state->error = readChunk_cHRM(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
- state->error = readChunk_sRGB(&state->info_png, data, chunkLength);
- if(state->error) break;
- } else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
- state->error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength);
- if(state->error) break;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- } else /*it's not an implemented chunk type, so ignore it: skip over the data*/ {
- /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/
- if(!state->decoder.ignore_critical && !lodepng_chunk_ancillary(chunk)) {
- CERROR_BREAK(state->error, 69);
- }
-
- unknown = 1;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- if(state->decoder.remember_unknown_chunks) {
- state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1],
- &state->info_png.unknown_chunks_size[critical_pos - 1], chunk);
- if(state->error) break;
- }
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- }
-
- if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/ {
- if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/
- }
-
- if(!IEND) chunk = lodepng_chunk_next_const(chunk, in + insize);
- }
-
- if(!state->error && state->info_png.color.colortype == LCT_PALETTE && !state->info_png.color.palette) {
- state->error = 106; /* error: PNG file must have PLTE chunk if color type is palette */
- }
-
- if(!state->error) {
- /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation.
- If the decompressed size does not match the prediction, the image must be corrupt.*/
- if(state->info_png.interlace_method == 0) {
- size_t bpp = lodepng_get_bpp(&state->info_png.color);
- expected_size = lodepng_get_raw_size_idat(*w, *h, bpp);
- } else {
- size_t bpp = lodepng_get_bpp(&state->info_png.color);
- /*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/
- expected_size = 0;
- expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp);
- if(*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp);
- expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp);
- if(*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp);
- expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp);
- if(*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp);
- expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp);
- }
-
- state->error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state->decoder.zlibsettings);
- }
- if(!state->error && scanlines_size != expected_size) state->error = 91; /*decompressed size doesn't match prediction*/
- lodepng_free(idat);
-
- if(!state->error) {
- outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color);
- *out = (unsigned char*)lodepng_malloc(outsize);
- if(!*out) state->error = 83; /*alloc fail*/
- }
- if(!state->error) {
- lodepng_memset(*out, 0, outsize);
- state->error = postProcessScanlines(*out, scanlines, *w, *h, &state->info_png);
- }
- lodepng_free(scanlines);
-}
-
-unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h,
- LodePNGState* state,
- const unsigned char* in, size_t insize) {
- *out = 0;
- decodeGeneric(out, w, h, state, in, insize);
- if(state->error) return state->error;
- if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) {
- /*same color type, no copying or converting of data needed*/
- /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype
- the raw image has to the end user*/
- if(!state->decoder.color_convert) {
- state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color);
- if(state->error) return state->error;
- }
- } else { /*color conversion needed*/
- unsigned char* data = *out;
- size_t outsize;
-
- /*TODO: check if this works according to the statement in the documentation: "The converter can convert
- from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/
- if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA)
- && !(state->info_raw.bitdepth == 8)) {
- return 56; /*unsupported color mode conversion*/
- }
-
- outsize = lodepng_get_raw_size(*w, *h, &state->info_raw);
- *out = (unsigned char*)lodepng_malloc(outsize);
- if(!(*out)) {
- state->error = 83; /*alloc fail*/
- }
- else state->error = lodepng_convert(*out, data, &state->info_raw,
- &state->info_png.color, *w, *h);
- lodepng_free(data);
- }
- return state->error;
-}
-
-unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in,
- size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
- unsigned error;
- LodePNGState state;
- lodepng_state_init(&state);
- state.info_raw.colortype = colortype;
- state.info_raw.bitdepth = bitdepth;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*disable reading things that this function doesn't output*/
- state.decoder.read_text_chunks = 0;
- state.decoder.remember_unknown_chunks = 0;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- error = lodepng_decode(out, w, h, &state, in, insize);
- lodepng_state_cleanup(&state);
- return error;
-}
-
-unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) {
- return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8);
-}
-
-unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) {
- return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8);
-}
-
-#ifdef LODEPNG_COMPILE_DISK
-unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename,
- LodePNGColorType colortype, unsigned bitdepth) {
- unsigned char* buffer = 0;
- size_t buffersize;
- unsigned error;
- /* safe output values in case error happens */
- *out = 0;
- *w = *h = 0;
- error = lodepng_load_file(&buffer, &buffersize, filename);
- if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth);
- lodepng_free(buffer);
- return error;
-}
-
-unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) {
- return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8);
-}
-
-unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) {
- return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8);
-}
-#endif /*LODEPNG_COMPILE_DISK*/
-
-void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) {
- settings->color_convert = 1;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- settings->read_text_chunks = 1;
- settings->remember_unknown_chunks = 0;
- settings->max_text_size = 16777216;
- settings->max_icc_size = 16777216; /* 16MB is much more than enough for any reasonable ICC profile */
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- settings->ignore_crc = 0;
- settings->ignore_critical = 0;
- settings->ignore_end = 0;
- lodepng_decompress_settings_init(&settings->zlibsettings);
-}
-
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER)
-
-void lodepng_state_init(LodePNGState* state) {
-#ifdef LODEPNG_COMPILE_DECODER
- lodepng_decoder_settings_init(&state->decoder);
-#endif /*LODEPNG_COMPILE_DECODER*/
-#ifdef LODEPNG_COMPILE_ENCODER
- lodepng_encoder_settings_init(&state->encoder);
-#endif /*LODEPNG_COMPILE_ENCODER*/
- lodepng_color_mode_init(&state->info_raw);
- lodepng_info_init(&state->info_png);
- state->error = 1;
-}
-
-void lodepng_state_cleanup(LodePNGState* state) {
- lodepng_color_mode_cleanup(&state->info_raw);
- lodepng_info_cleanup(&state->info_png);
-}
-
-void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source) {
- lodepng_state_cleanup(dest);
- *dest = *source;
- lodepng_color_mode_init(&dest->info_raw);
- lodepng_info_init(&dest->info_png);
- dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return;
- dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); if(dest->error) return;
-}
-
-#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* / PNG Encoder / */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-
-static unsigned writeSignature(ucvector* out) {
- size_t pos = out->size;
- const unsigned char signature[] = {137, 80, 78, 71, 13, 10, 26, 10};
- /*8 bytes PNG signature, aka the magic bytes*/
- if(!ucvector_resize(out, out->size + 8)) return 83; /*alloc fail*/
- lodepng_memcpy(out->data + pos, signature, 8);
- return 0;
-}
-
-static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) {
- unsigned char *chunk, *data;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 13, "IHDR"));
- data = chunk + 8;
-
- lodepng_set32bitInt(data + 0, w); /*width*/
- lodepng_set32bitInt(data + 4, h); /*height*/
- data[8] = (unsigned char)bitdepth; /*bit depth*/
- data[9] = (unsigned char)colortype; /*color type*/
- data[10] = 0; /*compression method*/
- data[11] = 0; /*filter method*/
- data[12] = interlace_method; /*interlace method*/
-
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-/* only adds the chunk if needed (there is a key or palette with alpha) */
-static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) {
- unsigned char* chunk;
- size_t i, j = 8;
-
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, info->palettesize * 3, "PLTE"));
-
- for(i = 0; i != info->palettesize; ++i) {
- /*add all channels except alpha channel*/
- chunk[j++] = info->palette[i * 4 + 0];
- chunk[j++] = info->palette[i * 4 + 1];
- chunk[j++] = info->palette[i * 4 + 2];
- }
-
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) {
- unsigned char* chunk = 0;
-
- if(info->colortype == LCT_PALETTE) {
- size_t i, amount = info->palettesize;
- /*the tail of palette values that all have 255 as alpha, does not have to be encoded*/
- for(i = info->palettesize; i != 0; --i) {
- if(info->palette[4 * (i - 1) + 3] != 255) break;
- --amount;
- }
- if(amount) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, amount, "tRNS"));
- /*add the alpha channel values from the palette*/
- for(i = 0; i != amount; ++i) chunk[8 + i] = info->palette[4 * i + 3];
- }
- } else if(info->colortype == LCT_GREY) {
- if(info->key_defined) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "tRNS"));
- chunk[8] = (unsigned char)(info->key_r >> 8);
- chunk[9] = (unsigned char)(info->key_r & 255);
- }
- } else if(info->colortype == LCT_RGB) {
- if(info->key_defined) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "tRNS"));
- chunk[8] = (unsigned char)(info->key_r >> 8);
- chunk[9] = (unsigned char)(info->key_r & 255);
- chunk[10] = (unsigned char)(info->key_g >> 8);
- chunk[11] = (unsigned char)(info->key_g & 255);
- chunk[12] = (unsigned char)(info->key_b >> 8);
- chunk[13] = (unsigned char)(info->key_b & 255);
- }
- }
-
- if(chunk) lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize,
- LodePNGCompressSettings* zlibsettings) {
- unsigned error = 0;
- unsigned char* zlib = 0;
- size_t zlibsize = 0;
-
- error = zlib_compress(&zlib, &zlibsize, data, datasize, zlibsettings);
- if(!error) {
- error = lodepng_chunk_createv(out, zlibsize, "IDAT", zlib);
- }
- lodepng_free(zlib);
- return error;
-}
-
-static unsigned addChunk_IEND(ucvector* out) {
- return lodepng_chunk_createv(out, 0, "IEND", 0);
-}
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-
-static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) {
- unsigned char* chunk = 0;
- size_t keysize = lodepng_strlen(keyword), textsize = lodepng_strlen(textstring);
- size_t size = keysize + 1 + textsize;
- if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, size, "tEXt"));
- lodepng_memcpy(chunk + 8, keyword, keysize);
- chunk[8 + keysize] = 0; /*null termination char*/
- lodepng_memcpy(chunk + 9 + keysize, textstring, textsize);
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring,
- LodePNGCompressSettings* zlibsettings) {
- unsigned error = 0;
- unsigned char* chunk = 0;
- unsigned char* compressed = 0;
- size_t compressedsize = 0;
- size_t textsize = lodepng_strlen(textstring);
- size_t keysize = lodepng_strlen(keyword);
- if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
-
- error = zlib_compress(&compressed, &compressedsize,
- (const unsigned char*)textstring, textsize, zlibsettings);
- if(!error) {
- size_t size = keysize + 2 + compressedsize;
- error = lodepng_chunk_init(&chunk, out, size, "zTXt");
- }
- if(!error) {
- lodepng_memcpy(chunk + 8, keyword, keysize);
- chunk[8 + keysize] = 0; /*null termination char*/
- chunk[9 + keysize] = 0; /*compression method: 0*/
- lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
- lodepng_chunk_generate_crc(chunk);
- }
-
- lodepng_free(compressed);
- return error;
-}
-
-static unsigned addChunk_iTXt(ucvector* out, unsigned compress, const char* keyword, const char* langtag,
- const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings) {
- unsigned error = 0;
- unsigned char* chunk = 0;
- unsigned char* compressed = 0;
- size_t compressedsize = 0;
- size_t textsize = lodepng_strlen(textstring);
- size_t keysize = lodepng_strlen(keyword), langsize = lodepng_strlen(langtag), transsize = lodepng_strlen(transkey);
-
- if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
-
- if(compress) {
- error = zlib_compress(&compressed, &compressedsize,
- (const unsigned char*)textstring, textsize, zlibsettings);
- }
- if(!error) {
- size_t size = keysize + 3 + langsize + 1 + transsize + 1 + (compress ? compressedsize : textsize);
- error = lodepng_chunk_init(&chunk, out, size, "iTXt");
- }
- if(!error) {
- size_t pos = 8;
- lodepng_memcpy(chunk + pos, keyword, keysize);
- pos += keysize;
- chunk[pos++] = 0; /*null termination char*/
- chunk[pos++] = (compress ? 1 : 0); /*compression flag*/
- chunk[pos++] = 0; /*compression method: 0*/
- lodepng_memcpy(chunk + pos, langtag, langsize);
- pos += langsize;
- chunk[pos++] = 0; /*null termination char*/
- lodepng_memcpy(chunk + pos, transkey, transsize);
- pos += transsize;
- chunk[pos++] = 0; /*null termination char*/
- if(compress) {
- lodepng_memcpy(chunk + pos, compressed, compressedsize);
- } else {
- lodepng_memcpy(chunk + pos, textstring, textsize);
- }
- lodepng_chunk_generate_crc(chunk);
- }
-
- lodepng_free(compressed);
- return error;
-}
-
-static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) {
- unsigned char* chunk = 0;
- if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "bKGD"));
- chunk[8] = (unsigned char)(info->background_r >> 8);
- chunk[9] = (unsigned char)(info->background_r & 255);
- } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "bKGD"));
- chunk[8] = (unsigned char)(info->background_r >> 8);
- chunk[9] = (unsigned char)(info->background_r & 255);
- chunk[10] = (unsigned char)(info->background_g >> 8);
- chunk[11] = (unsigned char)(info->background_g & 255);
- chunk[12] = (unsigned char)(info->background_b >> 8);
- chunk[13] = (unsigned char)(info->background_b & 255);
- } else if(info->color.colortype == LCT_PALETTE) {
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "bKGD"));
- chunk[8] = (unsigned char)(info->background_r & 255); /*palette index*/
- }
- if(chunk) lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) {
- unsigned char* chunk;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 7, "tIME"));
- chunk[8] = (unsigned char)(time->year >> 8);
- chunk[9] = (unsigned char)(time->year & 255);
- chunk[10] = (unsigned char)time->month;
- chunk[11] = (unsigned char)time->day;
- chunk[12] = (unsigned char)time->hour;
- chunk[13] = (unsigned char)time->minute;
- chunk[14] = (unsigned char)time->second;
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) {
- unsigned char* chunk;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 9, "pHYs"));
- lodepng_set32bitInt(chunk + 8, info->phys_x);
- lodepng_set32bitInt(chunk + 12, info->phys_y);
- chunk[16] = info->phys_unit;
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) {
- unsigned char* chunk;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "gAMA"));
- lodepng_set32bitInt(chunk + 8, info->gama_gamma);
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) {
- unsigned char* chunk;
- CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 32, "cHRM"));
- lodepng_set32bitInt(chunk + 8, info->chrm_white_x);
- lodepng_set32bitInt(chunk + 12, info->chrm_white_y);
- lodepng_set32bitInt(chunk + 16, info->chrm_red_x);
- lodepng_set32bitInt(chunk + 20, info->chrm_red_y);
- lodepng_set32bitInt(chunk + 24, info->chrm_green_x);
- lodepng_set32bitInt(chunk + 28, info->chrm_green_y);
- lodepng_set32bitInt(chunk + 32, info->chrm_blue_x);
- lodepng_set32bitInt(chunk + 36, info->chrm_blue_y);
- lodepng_chunk_generate_crc(chunk);
- return 0;
-}
-
-static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) {
- unsigned char data = info->srgb_intent;
- return lodepng_chunk_createv(out, 1, "sRGB", &data);
-}
-
-static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, LodePNGCompressSettings* zlibsettings) {
- unsigned error = 0;
- unsigned char* chunk = 0;
- unsigned char* compressed = 0;
- size_t compressedsize = 0;
- size_t keysize = lodepng_strlen(info->iccp_name);
-
- if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
- error = zlib_compress(&compressed, &compressedsize,
- info->iccp_profile, info->iccp_profile_size, zlibsettings);
- if(!error) {
- size_t size = keysize + 2 + compressedsize;
- error = lodepng_chunk_init(&chunk, out, size, "iCCP");
- }
- if(!error) {
- lodepng_memcpy(chunk + 8, info->iccp_name, keysize);
- chunk[8 + keysize] = 0; /*null termination char*/
- chunk[9 + keysize] = 0; /*compression method: 0*/
- lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
- lodepng_chunk_generate_crc(chunk);
- }
-
- lodepng_free(compressed);
- return error;
-}
-
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline,
- size_t length, size_t bytewidth, unsigned char filterType) {
- size_t i;
- switch(filterType) {
- case 0: /*None*/
- for(i = 0; i != length; ++i) out[i] = scanline[i];
- break;
- case 1: /*Sub*/
- for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
- for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth];
- break;
- case 2: /*Up*/
- if(prevline) {
- for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i];
- } else {
- for(i = 0; i != length; ++i) out[i] = scanline[i];
- }
- break;
- case 3: /*Average*/
- if(prevline) {
- for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1);
- for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1);
- } else {
- for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
- for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1);
- }
- break;
- case 4: /*Paeth*/
- if(prevline) {
- /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/
- for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]);
- for(i = bytewidth; i < length; ++i) {
- out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth]));
- }
- } else {
- for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
- /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/
- for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]);
- }
- break;
- default: return; /*invalid filter type given*/
- }
-}
-
-/* integer binary logarithm, max return value is 31 */
-static size_t ilog2(size_t i) {
- size_t result = 0;
- if(i >= 65536) { result += 16; i >>= 16; }
- if(i >= 256) { result += 8; i >>= 8; }
- if(i >= 16) { result += 4; i >>= 4; }
- if(i >= 4) { result += 2; i >>= 2; }
- if(i >= 2) { result += 1; /*i >>= 1;*/ }
- return result;
-}
-
-/* integer approximation for i * log2(i), helper function for LFS_ENTROPY */
-static size_t ilog2i(size_t i) {
- size_t l;
- if(i == 0) return 0;
- l = ilog2(i);
- /* approximate i*log2(i): l is integer logarithm, ((i - (1u << l)) << 1u)
- linearly approximates the missing fractional part multiplied by i */
- return i * l + ((i - (1u << l)) << 1u);
-}
-
-static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h,
- const LodePNGColorMode* color, const LodePNGEncoderSettings* settings) {
- /*
- For PNG filter method 0
- out must be a buffer with as size: h + (w * h * bpp + 7u) / 8u, because there are
- the scanlines with 1 extra byte per scanline
- */
-
- unsigned bpp = lodepng_get_bpp(color);
- /*the width of a scanline in bytes, not including the filter type*/
- size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;
-
- /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
- size_t bytewidth = (bpp + 7u) / 8u;
- const unsigned char* prevline = 0;
- unsigned x, y;
- unsigned error = 0;
- LodePNGFilterStrategy strategy = settings->filter_strategy;
-
- /*
- There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard:
- * If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e.
- use fixed filtering, with the filter None).
- * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is
- not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply
- all five filters and select the filter that produces the smallest sum of absolute values per row.
- This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true.
-
- If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed,
- but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum
- heuristic is used.
- */
- if(settings->filter_palette_zero &&
- (color->colortype == LCT_PALETTE || color->bitdepth < 8)) strategy = LFS_ZERO;
-
- if(bpp == 0) return 31; /*error: invalid color type*/
-
- if(strategy >= LFS_ZERO && strategy <= LFS_FOUR) {
- unsigned char type = (unsigned char)strategy;
- for(y = 0; y != h; ++y) {
- size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
- size_t inindex = linebytes * y;
- out[outindex] = type; /*filter type byte*/
- filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
- prevline = &in[inindex];
- }
- } else if(strategy == LFS_MINSUM) {
- /*adaptive filtering*/
- unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
- size_t smallest = 0;
- unsigned char type, bestType = 0;
-
- for(type = 0; type != 5; ++type) {
- attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
- if(!attempt[type]) error = 83; /*alloc fail*/
- }
-
- if(!error) {
- for(y = 0; y != h; ++y) {
- /*try the 5 filter types*/
- for(type = 0; type != 5; ++type) {
- size_t sum = 0;
- filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
-
- /*calculate the sum of the result*/
- if(type == 0) {
- for(x = 0; x != linebytes; ++x) sum += (unsigned char)(attempt[type][x]);
- } else {
- for(x = 0; x != linebytes; ++x) {
- /*For differences, each byte should be treated as signed, values above 127 are negative
- (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there.
- This means filtertype 0 is almost never chosen, but that is justified.*/
- unsigned char s = attempt[type][x];
- sum += s < 128 ? s : (255U - s);
- }
- }
-
- /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
- if(type == 0 || sum < smallest) {
- bestType = type;
- smallest = sum;
- }
- }
-
- prevline = &in[y * linebytes];
-
- /*now fill the out values*/
- out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
- for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
- }
- }
-
- for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
- } else if(strategy == LFS_ENTROPY) {
- unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
- size_t bestSum = 0;
- unsigned type, bestType = 0;
- unsigned count[256];
-
- for(type = 0; type != 5; ++type) {
- attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
- if(!attempt[type]) error = 83; /*alloc fail*/
- }
-
- if(!error) {
- for(y = 0; y != h; ++y) {
- /*try the 5 filter types*/
- for(type = 0; type != 5; ++type) {
- size_t sum = 0;
- filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
- lodepng_memset(count, 0, 256 * sizeof(*count));
- for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]];
- ++count[type]; /*the filter type itself is part of the scanline*/
- for(x = 0; x != 256; ++x) {
- sum += ilog2i(count[x]);
- }
- /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
- if(type == 0 || sum > bestSum) {
- bestType = type;
- bestSum = sum;
- }
- }
-
- prevline = &in[y * linebytes];
-
- /*now fill the out values*/
- out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
- for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
- }
- }
-
- for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
- } else if(strategy == LFS_PREDEFINED) {
- for(y = 0; y != h; ++y) {
- size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
- size_t inindex = linebytes * y;
- unsigned char type = settings->predefined_filters[y];
- out[outindex] = type; /*filter type byte*/
- filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
- prevline = &in[inindex];
- }
- } else if(strategy == LFS_BRUTE_FORCE) {
- /*brute force filter chooser.
- deflate the scanline after every filter attempt to see which one deflates best.
- This is very slow and gives only slightly smaller, sometimes even larger, result*/
- size_t size[5];
- unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/
- size_t smallest = 0;
- unsigned type = 0, bestType = 0;
- unsigned char* dummy;
- LodePNGCompressSettings zlibsettings;
- lodepng_memcpy(&zlibsettings, &settings->zlibsettings, sizeof(LodePNGCompressSettings));
- /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose,
- to simulate the true case where the tree is the same for the whole image. Sometimes it gives
- better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare
- cases better compression. It does make this a bit less slow, so it's worth doing this.*/
- zlibsettings.btype = 1;
- /*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG
- images only, so disable it*/
- zlibsettings.custom_zlib = 0;
- zlibsettings.custom_deflate = 0;
- for(type = 0; type != 5; ++type) {
- attempt[type] = (unsigned char*)lodepng_malloc(linebytes);
- if(!attempt[type]) error = 83; /*alloc fail*/
- }
- if(!error) {
- for(y = 0; y != h; ++y) /*try the 5 filter types*/ {
- for(type = 0; type != 5; ++type) {
- unsigned testsize = (unsigned)linebytes;
- /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/
-
- filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
- size[type] = 0;
- dummy = 0;
- zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings);
- lodepng_free(dummy);
- /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/
- if(type == 0 || size[type] < smallest) {
- bestType = type;
- smallest = size[type];
- }
- }
- prevline = &in[y * linebytes];
- out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
- for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
- }
- }
- for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
- }
- else return 88; /* unknown filter strategy */
-
- return error;
-}
-
-static void addPaddingBits(unsigned char* out, const unsigned char* in,
- size_t olinebits, size_t ilinebits, unsigned h) {
- /*The opposite of the removePaddingBits function
- olinebits must be >= ilinebits*/
- unsigned y;
- size_t diff = olinebits - ilinebits;
- size_t obp = 0, ibp = 0; /*bit pointers*/
- for(y = 0; y != h; ++y) {
- size_t x;
- for(x = 0; x < ilinebits; ++x) {
- unsigned char bit = readBitFromReversedStream(&ibp, in);
- setBitOfReversedStream(&obp, out, bit);
- }
- /*obp += diff; --> no, fill in some value in the padding bits too, to avoid
- "Use of uninitialised value of size ###" warning from valgrind*/
- for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0);
- }
-}
-
-/*
-in: non-interlaced image with size w*h
-out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with
- no padding bits between scanlines, but between reduced images so that each
- reduced image starts at a byte.
-bpp: bits per pixel
-there are no padding bits, not between scanlines, not between reduced images
-in has the following size in bits: w * h * bpp.
-out is possibly bigger due to padding bits between reduced images
-NOTE: comments about padding bits are only relevant if bpp < 8
-*/
-static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) {
- unsigned passw[7], passh[7];
- size_t filter_passstart[8], padded_passstart[8], passstart[8];
- unsigned i;
-
- Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
-
- if(bpp >= 8) {
- for(i = 0; i != 7; ++i) {
- unsigned x, y, b;
- size_t bytewidth = bpp / 8u;
- for(y = 0; y < passh[i]; ++y)
- for(x = 0; x < passw[i]; ++x) {
- size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
- size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth;
- for(b = 0; b < bytewidth; ++b) {
- out[pixeloutstart + b] = in[pixelinstart + b];
- }
- }
- }
- } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
- for(i = 0; i != 7; ++i) {
- unsigned x, y, b;
- unsigned ilinebits = bpp * passw[i];
- unsigned olinebits = bpp * w;
- size_t obp, ibp; /*bit pointers (for out and in buffer)*/
- for(y = 0; y < passh[i]; ++y)
- for(x = 0; x < passw[i]; ++x) {
- ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
- obp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
- for(b = 0; b < bpp; ++b) {
- unsigned char bit = readBitFromReversedStream(&ibp, in);
- setBitOfReversedStream(&obp, out, bit);
- }
- }
- }
- }
-}
-
-/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image.
-return value is error**/
-static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in,
- unsigned w, unsigned h,
- const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings) {
- /*
- This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps:
- *) if no Adam7: 1) add padding bits (= possible extra bits per scanline if bpp < 8) 2) filter
- *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter
- */
- unsigned bpp = lodepng_get_bpp(&info_png->color);
- unsigned error = 0;
-
- if(info_png->interlace_method == 0) {
- *outsize = h + (h * ((w * bpp + 7u) / 8u)); /*image size plus an extra byte per scanline + possible padding bits*/
- *out = (unsigned char*)lodepng_malloc(*outsize);
- if(!(*out) && (*outsize)) error = 83; /*alloc fail*/
-
- if(!error) {
- /*non multiple of 8 bits per scanline, padding bits needed per scanline*/
- if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
- unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7u) / 8u));
- if(!padded) error = 83; /*alloc fail*/
- if(!error) {
- addPaddingBits(padded, in, ((w * bpp + 7u) / 8u) * 8u, w * bpp, h);
- error = filter(*out, padded, w, h, &info_png->color, settings);
- }
- lodepng_free(padded);
- } else {
- /*we can immediately filter into the out buffer, no other steps needed*/
- error = filter(*out, in, w, h, &info_png->color, settings);
- }
- }
- } else /*interlace_method is 1 (Adam7)*/ {
- unsigned passw[7], passh[7];
- size_t filter_passstart[8], padded_passstart[8], passstart[8];
- unsigned char* adam7;
-
- Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
-
- *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/
- *out = (unsigned char*)lodepng_malloc(*outsize);
- if(!(*out)) error = 83; /*alloc fail*/
-
- adam7 = (unsigned char*)lodepng_malloc(passstart[7]);
- if(!adam7 && passstart[7]) error = 83; /*alloc fail*/
-
- if(!error) {
- unsigned i;
-
- Adam7_interlace(adam7, in, w, h, bpp);
- for(i = 0; i != 7; ++i) {
- if(bpp < 8) {
- unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]);
- if(!padded) ERROR_BREAK(83); /*alloc fail*/
- addPaddingBits(padded, &adam7[passstart[i]],
- ((passw[i] * bpp + 7u) / 8u) * 8u, passw[i] * bpp, passh[i]);
- error = filter(&(*out)[filter_passstart[i]], padded,
- passw[i], passh[i], &info_png->color, settings);
- lodepng_free(padded);
- } else {
- error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]],
- passw[i], passh[i], &info_png->color, settings);
- }
-
- if(error) break;
- }
- }
-
- lodepng_free(adam7);
- }
-
- return error;
-}
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-static unsigned addUnknownChunks(ucvector* out, unsigned char* data, size_t datasize) {
- unsigned char* inchunk = data;
- while((size_t)(inchunk - data) < datasize) {
- CERROR_TRY_RETURN(lodepng_chunk_append(&out->data, &out->size, inchunk));
- out->allocsize = out->size; /*fix the allocsize again*/
- inchunk = lodepng_chunk_next(inchunk, data + datasize);
- }
- return 0;
-}
-
-static unsigned isGrayICCProfile(const unsigned char* profile, unsigned size) {
- /*
- It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19
- are "RGB ". We do not perform any full parsing of the ICC profile here, other
- than check those 4 bytes to grayscale profile. Other than that, validity of
- the profile is not checked. This is needed only because the PNG specification
- requires using a non-gray color model if there is an ICC profile with "RGB "
- (sadly limiting compression opportunities if the input data is grayscale RGB
- data), and requires using a gray color model if it is "GRAY".
- */
- if(size < 20) return 0;
- return profile[16] == 'G' && profile[17] == 'R' && profile[18] == 'A' && profile[19] == 'Y';
-}
-
-static unsigned isRGBICCProfile(const unsigned char* profile, unsigned size) {
- /* See comment in isGrayICCProfile*/
- if(size < 20) return 0;
- return profile[16] == 'R' && profile[17] == 'G' && profile[18] == 'B' && profile[19] == ' ';
-}
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-unsigned lodepng_encode(unsigned char** out, size_t* outsize,
- const unsigned char* image, unsigned w, unsigned h,
- LodePNGState* state) {
- unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/
- size_t datasize = 0;
- ucvector outv = ucvector_init(NULL, 0);
- LodePNGInfo info;
- const LodePNGInfo* info_png = &state->info_png;
-
- lodepng_info_init(&info);
-
- /*provide some proper output values if error will happen*/
- *out = 0;
- *outsize = 0;
- state->error = 0;
-
- /*check input values validity*/
- if((info_png->color.colortype == LCT_PALETTE || state->encoder.force_palette)
- && (info_png->color.palettesize == 0 || info_png->color.palettesize > 256)) {
- state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/
- goto cleanup;
- }
- if(state->encoder.zlibsettings.btype > 2) {
- state->error = 61; /*error: invalid btype*/
- goto cleanup;
- }
- if(info_png->interlace_method > 1) {
- state->error = 71; /*error: invalid interlace mode*/
- goto cleanup;
- }
- state->error = checkColorValidity(info_png->color.colortype, info_png->color.bitdepth);
- if(state->error) goto cleanup; /*error: invalid color type given*/
- state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth);
- if(state->error) goto cleanup; /*error: invalid color type given*/
-
- /* color convert and compute scanline filter types */
- lodepng_info_copy(&info, &state->info_png);
- if(state->encoder.auto_convert) {
- LodePNGColorStats stats;
- lodepng_color_stats_init(&stats);
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- if(info_png->iccp_defined &&
- isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) {
- /*the PNG specification does not allow to use palette with a GRAY ICC profile, even
- if the palette has only gray colors, so disallow it.*/
- stats.allow_palette = 0;
- }
- if(info_png->iccp_defined &&
- isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) {
- /*the PNG specification does not allow to use grayscale color with RGB ICC profile, so disallow gray.*/
- stats.allow_greyscale = 0;
- }
-#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
- state->error = lodepng_compute_color_stats(&stats, image, w, h, &state->info_raw);
- if(state->error) goto cleanup;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- if(info_png->background_defined) {
- /*the background chunk's color must be taken into account as well*/
- unsigned r = 0, g = 0, b = 0;
- LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16);
- lodepng_convert_rgb(&r, &g, &b, info_png->background_r, info_png->background_g, info_png->background_b, &mode16, &info_png->color);
- state->error = lodepng_color_stats_add(&stats, r, g, b, 65535);
- if(state->error) goto cleanup;
- }
-#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
- state->error = auto_choose_color(&info.color, &state->info_raw, &stats);
- if(state->error) goto cleanup;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*also convert the background chunk*/
- if(info_png->background_defined) {
- if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b,
- info_png->background_r, info_png->background_g, info_png->background_b, &info.color, &info_png->color)) {
- state->error = 104;
- goto cleanup;
- }
- }
-#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
- }
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- if(info_png->iccp_defined) {
- unsigned gray_icc = isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size);
- unsigned rgb_icc = isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size);
- unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA;
- if(!gray_icc && !rgb_icc) {
- state->error = 100; /* Disallowed profile color type for PNG */
- goto cleanup;
- }
- if(gray_icc != gray_png) {
- /*Not allowed to use RGB/RGBA/palette with GRAY ICC profile or vice versa,
- or in case of auto_convert, it wasn't possible to find appropriate model*/
- state->error = state->encoder.auto_convert ? 102 : 101;
- goto cleanup;
- }
- }
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) {
- unsigned char* converted;
- size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7u) / 8u;
-
- converted = (unsigned char*)lodepng_malloc(size);
- if(!converted && size) state->error = 83; /*alloc fail*/
- if(!state->error) {
- state->error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h);
- }
- if(!state->error) {
- state->error = preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder);
- }
- lodepng_free(converted);
- if(state->error) goto cleanup;
- } else {
- state->error = preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder);
- if(state->error) goto cleanup;
- }
-
- /* output all PNG chunks */ {
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- size_t i;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- /*write signature and chunks*/
- state->error = writeSignature(&outv);
- if(state->error) goto cleanup;
- /*IHDR*/
- state->error = addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method);
- if(state->error) goto cleanup;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*unknown chunks between IHDR and PLTE*/
- if(info.unknown_chunks_data[0]) {
- state->error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]);
- if(state->error) goto cleanup;
- }
- /*color profile chunks must come before PLTE */
- if(info.iccp_defined) {
- state->error = addChunk_iCCP(&outv, &info, &state->encoder.zlibsettings);
- if(state->error) goto cleanup;
- }
- if(info.srgb_defined) {
- state->error = addChunk_sRGB(&outv, &info);
- if(state->error) goto cleanup;
- }
- if(info.gama_defined) {
- state->error = addChunk_gAMA(&outv, &info);
- if(state->error) goto cleanup;
- }
- if(info.chrm_defined) {
- state->error = addChunk_cHRM(&outv, &info);
- if(state->error) goto cleanup;
- }
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- /*PLTE*/
- if(info.color.colortype == LCT_PALETTE) {
- state->error = addChunk_PLTE(&outv, &info.color);
- if(state->error) goto cleanup;
- }
- if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) {
- /*force_palette means: write suggested palette for truecolor in PLTE chunk*/
- state->error = addChunk_PLTE(&outv, &info.color);
- if(state->error) goto cleanup;
- }
- /*tRNS (this will only add if when necessary) */
- state->error = addChunk_tRNS(&outv, &info.color);
- if(state->error) goto cleanup;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*bKGD (must come between PLTE and the IDAt chunks*/
- if(info.background_defined) {
- state->error = addChunk_bKGD(&outv, &info);
- if(state->error) goto cleanup;
- }
- /*pHYs (must come before the IDAT chunks)*/
- if(info.phys_defined) {
- state->error = addChunk_pHYs(&outv, &info);
- if(state->error) goto cleanup;
- }
-
- /*unknown chunks between PLTE and IDAT*/
- if(info.unknown_chunks_data[1]) {
- state->error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]);
- if(state->error) goto cleanup;
- }
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- /*IDAT (multiple IDAT chunks must be consecutive)*/
- state->error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings);
- if(state->error) goto cleanup;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*tIME*/
- if(info.time_defined) {
- state->error = addChunk_tIME(&outv, &info.time);
- if(state->error) goto cleanup;
- }
- /*tEXt and/or zTXt*/
- for(i = 0; i != info.text_num; ++i) {
- if(lodepng_strlen(info.text_keys[i]) > 79) {
- state->error = 66; /*text chunk too large*/
- goto cleanup;
- }
- if(lodepng_strlen(info.text_keys[i]) < 1) {
- state->error = 67; /*text chunk too small*/
- goto cleanup;
- }
- if(state->encoder.text_compression) {
- state->error = addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings);
- if(state->error) goto cleanup;
- } else {
- state->error = addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]);
- if(state->error) goto cleanup;
- }
- }
- /*LodePNG version id in text chunk*/
- if(state->encoder.add_id) {
- unsigned already_added_id_text = 0;
- for(i = 0; i != info.text_num; ++i) {
- const char* k = info.text_keys[i];
- /* Could use strcmp, but we're not calling or reimplementing this C library function for this use only */
- if(k[0] == 'L' && k[1] == 'o' && k[2] == 'd' && k[3] == 'e' &&
- k[4] == 'P' && k[5] == 'N' && k[6] == 'G' && k[7] == '\0') {
- already_added_id_text = 1;
- break;
- }
- }
- if(already_added_id_text == 0) {
- state->error = addChunk_tEXt(&outv, "LodePNG", LODEPNG_VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/
- if(state->error) goto cleanup;
- }
- }
- /*iTXt*/
- for(i = 0; i != info.itext_num; ++i) {
- if(lodepng_strlen(info.itext_keys[i]) > 79) {
- state->error = 66; /*text chunk too large*/
- goto cleanup;
- }
- if(lodepng_strlen(info.itext_keys[i]) < 1) {
- state->error = 67; /*text chunk too small*/
- goto cleanup;
- }
- state->error = addChunk_iTXt(
- &outv, state->encoder.text_compression,
- info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i],
- &state->encoder.zlibsettings);
- if(state->error) goto cleanup;
- }
-
- /*unknown chunks between IDAT and IEND*/
- if(info.unknown_chunks_data[2]) {
- state->error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]);
- if(state->error) goto cleanup;
- }
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
- state->error = addChunk_IEND(&outv);
- if(state->error) goto cleanup;
- }
-
-cleanup:
- lodepng_info_cleanup(&info);
- lodepng_free(data);
-
- /*instead of cleaning the vector up, give it to the output*/
- *out = outv.data;
- *outsize = outv.size;
-
- return state->error;
-}
-
-unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image,
- unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
- unsigned error;
- LodePNGState state;
- lodepng_state_init(&state);
- state.info_raw.colortype = colortype;
- state.info_raw.bitdepth = bitdepth;
- state.info_png.color.colortype = colortype;
- state.info_png.color.bitdepth = bitdepth;
- lodepng_encode(out, outsize, image, w, h, &state);
- error = state.error;
- lodepng_state_cleanup(&state);
- return error;
-}
-
-unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) {
- return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8);
-}
-
-unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) {
- return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8);
-}
-
-#ifdef LODEPNG_COMPILE_DISK
-unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth) {
- unsigned char* buffer;
- size_t buffersize;
- unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth);
- if(!error) error = lodepng_save_file(buffer, buffersize, filename);
- lodepng_free(buffer);
- return error;
-}
-
-unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) {
- return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8);
-}
-
-unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) {
- return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8);
-}
-#endif /*LODEPNG_COMPILE_DISK*/
-
-void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) {
- lodepng_compress_settings_init(&settings->zlibsettings);
- settings->filter_palette_zero = 1;
- settings->filter_strategy = LFS_MINSUM;
- settings->auto_convert = 1;
- settings->force_palette = 0;
- settings->predefined_filters = 0;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- settings->add_id = 0;
- settings->text_compression = 1;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-}
-
-#endif /*LODEPNG_COMPILE_ENCODER*/
-#endif /*LODEPNG_COMPILE_PNG*/
-
-#ifdef LODEPNG_COMPILE_ERROR_TEXT
-/*
-This returns the description of a numerical error code in English. This is also
-the documentation of all the error codes.
-*/
-const char* lodepng_error_text(unsigned code) {
- switch(code) {
- case 0: return "no error, everything went ok";
- case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/
- case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/
- case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/
- case 13: return "problem while processing dynamic deflate block";
- case 14: return "problem while processing dynamic deflate block";
- case 15: return "problem while processing dynamic deflate block";
- /*this error could happen if there are only 0 or 1 symbols present in the huffman code:*/
- case 16: return "invalid code while processing dynamic deflate block";
- case 17: return "end of out buffer memory reached while inflating";
- case 18: return "invalid distance code while inflating";
- case 19: return "end of out buffer memory reached while inflating";
- case 20: return "invalid deflate block BTYPE encountered while decoding";
- case 21: return "NLEN is not ones complement of LEN in a deflate block";
-
- /*end of out buffer memory reached while inflating:
- This can happen if the inflated deflate data is longer than the amount of bytes required to fill up
- all the pixels of the image, given the color depth and image dimensions. Something that doesn't
- happen in a normal, well encoded, PNG image.*/
- case 22: return "end of out buffer memory reached while inflating";
- case 23: return "end of in buffer memory reached while inflating";
- case 24: return "invalid FCHECK in zlib header";
- case 25: return "invalid compression method in zlib header";
- case 26: return "FDICT encountered in zlib header while it's not used for PNG";
- case 27: return "PNG file is smaller than a PNG header";
- /*Checks the magic file header, the first 8 bytes of the PNG file*/
- case 28: return "incorrect PNG signature, it's no PNG or corrupted";
- case 29: return "first chunk is not the header chunk";
- case 30: return "chunk length too large, chunk broken off at end of file";
- case 31: return "illegal PNG color type or bpp";
- case 32: return "illegal PNG compression method";
- case 33: return "illegal PNG filter method";
- case 34: return "illegal PNG interlace method";
- case 35: return "chunk length of a chunk is too large or the chunk too small";
- case 36: return "illegal PNG filter type encountered";
- case 37: return "illegal bit depth for this color type given";
- case 38: return "the palette is too small or too big"; /*0, or more than 256 colors*/
- case 39: return "tRNS chunk before PLTE or has more entries than palette size";
- case 40: return "tRNS chunk has wrong size for grayscale image";
- case 41: return "tRNS chunk has wrong size for RGB image";
- case 42: return "tRNS chunk appeared while it was not allowed for this color type";
- case 43: return "bKGD chunk has wrong size for palette image";
- case 44: return "bKGD chunk has wrong size for grayscale image";
- case 45: return "bKGD chunk has wrong size for RGB image";
- case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?";
- case 49: return "jumped past memory while generating dynamic huffman tree";
- case 50: return "jumped past memory while generating dynamic huffman tree";
- case 51: return "jumped past memory while inflating huffman block";
- case 52: return "jumped past memory while inflating";
- case 53: return "size of zlib data too small";
- case 54: return "repeat symbol in tree while there was no value symbol yet";
- /*jumped past tree while generating huffman tree, this could be when the
- tree will have more leaves than symbols after generating it out of the
- given lengths. They call this an oversubscribed dynamic bit lengths tree in zlib.*/
- case 55: return "jumped past tree while generating huffman tree";
- case 56: return "given output image colortype or bitdepth not supported for color conversion";
- case 57: return "invalid CRC encountered (checking CRC can be disabled)";
- case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)";
- case 59: return "requested color conversion not supported";
- case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)";
- case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)";
- /*LodePNG leaves the choice of RGB to grayscale conversion formula to the user.*/
- case 62: return "conversion from color to grayscale not supported";
- /*(2^31-1)*/
- case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk";
- /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/
- case 64: return "the length of the END symbol 256 in the Huffman tree is 0";
- case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes";
- case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte";
- case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors";
- case 69: return "unknown chunk type with 'critical' flag encountered by the decoder";
- case 71: return "invalid interlace mode given to encoder (must be 0 or 1)";
- case 72: return "while decoding, invalid compression method encountering in zTXt or iTXt chunk (it must be 0)";
- case 73: return "invalid tIME chunk size";
- case 74: return "invalid pHYs chunk size";
- /*length could be wrong, or data chopped off*/
- case 75: return "no null termination char found while decoding text chunk";
- case 76: return "iTXt chunk too short to contain required bytes";
- case 77: return "integer overflow in buffer size";
- case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/
- case 79: return "failed to open file for writing";
- case 80: return "tried creating a tree of 0 symbols";
- case 81: return "lazy matching at pos 0 is impossible";
- case 82: return "color conversion to palette requested while a color isn't in palette, or index out of bounds";
- case 83: return "memory allocation failed";
- case 84: return "given image too small to contain all pixels to be encoded";
- case 86: return "impossible offset in lz77 encoding (internal bug)";
- case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined";
- case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy";
- case 89: return "text chunk keyword too short or long: must have size 1-79";
- /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/
- case 90: return "windowsize must be a power of two";
- case 91: return "invalid decompressed idat size";
- case 92: return "integer overflow due to too many pixels";
- case 93: return "zero width or height is invalid";
- case 94: return "header chunk must have a size of 13 bytes";
- case 95: return "integer overflow with combined idat chunk size";
- case 96: return "invalid gAMA chunk size";
- case 97: return "invalid cHRM chunk size";
- case 98: return "invalid sRGB chunk size";
- case 99: return "invalid sRGB rendering intent";
- case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY";
- case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa";
- case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification";
- case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?";
- case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)";
- case 105: return "integer overflow of bitsize";
- case 106: return "PNG file must have PLTE chunk if color type is palette";
- case 107: return "color convert from palette mode requested without setting the palette data in it";
- case 108: return "tried to add more than 256 values to a palette";
- /*this limit can be configured in LodePNGDecompressSettings*/
- case 109: return "tried to decompress zlib or deflate data larger than desired max_output_size";
- case 110: return "custom zlib or inflate decompression failed";
- case 111: return "custom zlib or deflate compression failed";
- /*max text size limit can be configured in LodePNGDecoderSettings. This error prevents
- unreasonable memory consumption when decoding due to impossibly large text sizes.*/
- case 112: return "compressed text unreasonably large";
- /*max ICC size limit can be configured in LodePNGDecoderSettings. This error prevents
- unreasonable memory consumption when decoding due to impossibly large ICC profile*/
- case 113: return "ICC profile unreasonably large";
- }
- return "unknown error code";
-}
-#endif /*LODEPNG_COMPILE_ERROR_TEXT*/
-
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* // C++ Wrapper // */
-/* ////////////////////////////////////////////////////////////////////////// */
-/* ////////////////////////////////////////////////////////////////////////// */
-
-#ifdef LODEPNG_COMPILE_CPP
-namespace lodepng {
-
-#ifdef LODEPNG_COMPILE_DISK
-unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename) {
- long size = lodepng_filesize(filename.c_str());
- if(size < 0) return 78;
- buffer.resize((size_t)size);
- return size == 0 ? 0 : lodepng_buffer_file(&buffer[0], (size_t)size, filename.c_str());
-}
-
-/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
-unsigned save_file(const std::vector<unsigned char>& buffer, const std::string& filename) {
- return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str());
-}
-#endif /* LODEPNG_COMPILE_DISK */
-
-#ifdef LODEPNG_COMPILE_ZLIB
-#ifdef LODEPNG_COMPILE_DECODER
-unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings& settings) {
- unsigned char* buffer = 0;
- size_t buffersize = 0;
- unsigned error = zlib_decompress(&buffer, &buffersize, 0, in, insize, &settings);
- if(buffer) {
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- lodepng_free(buffer);
- }
- return error;
-}
-
-unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
- const LodePNGDecompressSettings& settings) {
- return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings);
-}
-#endif /* LODEPNG_COMPILE_DECODER */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
- const LodePNGCompressSettings& settings) {
- unsigned char* buffer = 0;
- size_t buffersize = 0;
- unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings);
- if(buffer) {
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- lodepng_free(buffer);
- }
- return error;
-}
-
-unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
- const LodePNGCompressSettings& settings) {
- return compress(out, in.empty() ? 0 : &in[0], in.size(), settings);
-}
-#endif /* LODEPNG_COMPILE_ENCODER */
-#endif /* LODEPNG_COMPILE_ZLIB */
-
-
-#ifdef LODEPNG_COMPILE_PNG
-
-State::State() {
- lodepng_state_init(this);
-}
-
-State::State(const State& other) {
- lodepng_state_init(this);
- lodepng_state_copy(this, &other);
-}
-
-State::~State() {
- lodepng_state_cleanup(this);
-}
-
-State& State::operator=(const State& other) {
- lodepng_state_copy(this, &other);
- return *this;
-}
-
-#ifdef LODEPNG_COMPILE_DECODER
-
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const unsigned char* in,
- size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
- unsigned char* buffer = 0;
- unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth);
- if(buffer && !error) {
- State state;
- state.info_raw.colortype = colortype;
- state.info_raw.bitdepth = bitdepth;
- size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- }
- lodepng_free(buffer);
- return error;
-}
-
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- const std::vector<unsigned char>& in, LodePNGColorType colortype, unsigned bitdepth) {
- return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth);
-}
-
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- State& state,
- const unsigned char* in, size_t insize) {
- unsigned char* buffer = NULL;
- unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize);
- if(buffer && !error) {
- size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- }
- lodepng_free(buffer);
- return error;
-}
-
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- State& state,
- const std::vector<unsigned char>& in) {
- return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size());
-}
-
-#ifdef LODEPNG_COMPILE_DISK
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename,
- LodePNGColorType colortype, unsigned bitdepth) {
- std::vector<unsigned char> buffer;
- /* safe output values in case error happens */
- w = h = 0;
- unsigned error = load_file(buffer, filename);
- if(error) return error;
- return decode(out, w, h, buffer, colortype, bitdepth);
-}
-#endif /* LODEPNG_COMPILE_DECODER */
-#endif /* LODEPNG_COMPILE_DISK */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-unsigned encode(std::vector<unsigned char>& out, const unsigned char* in, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth) {
- unsigned char* buffer;
- size_t buffersize;
- unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth);
- if(buffer) {
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- lodepng_free(buffer);
- }
- return error;
-}
-
-unsigned encode(std::vector<unsigned char>& out,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth) {
- if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
- return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
-}
-
-unsigned encode(std::vector<unsigned char>& out,
- const unsigned char* in, unsigned w, unsigned h,
- State& state) {
- unsigned char* buffer;
- size_t buffersize;
- unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state);
- if(buffer) {
- out.insert(out.end(), &buffer[0], &buffer[buffersize]);
- lodepng_free(buffer);
- }
- return error;
-}
-
-unsigned encode(std::vector<unsigned char>& out,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- State& state) {
- if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84;
- return encode(out, in.empty() ? 0 : &in[0], w, h, state);
-}
-
-#ifdef LODEPNG_COMPILE_DISK
-unsigned encode(const std::string& filename,
- const unsigned char* in, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth) {
- std::vector<unsigned char> buffer;
- unsigned error = encode(buffer, in, w, h, colortype, bitdepth);
- if(!error) error = save_file(buffer, filename);
- return error;
-}
-
-unsigned encode(const std::string& filename,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth) {
- if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
- return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
-}
-#endif /* LODEPNG_COMPILE_DISK */
-#endif /* LODEPNG_COMPILE_ENCODER */
-#endif /* LODEPNG_COMPILE_PNG */
-} /* namespace lodepng */
-#endif /*LODEPNG_COMPILE_CPP*/
diff --git a/src/png/lodepng.h b/src/png/lodepng.h
deleted file mode 100644
index 6801cb7..0000000
--- a/src/png/lodepng.h
+++ /dev/null
@@ -1,1977 +0,0 @@
-/*
-LodePNG version 20201017
-
-Copyright (c) 2005-2020 Lode Vandevenne
-
-This software is provided 'as-is', without any express or implied
-warranty. In no event will the authors be held liable for any damages
-arising from the use of this software.
-
-Permission is granted to anyone to use this software for any purpose,
-including commercial applications, and to alter it and redistribute it
-freely, subject to the following restrictions:
-
- 1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
-
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
-
- 3. This notice may not be removed or altered from any source
- distribution.
-*/
-
-#ifndef LODEPNG_H
-#define LODEPNG_H
-
-#include <string.h> /*for size_t*/
-
-extern const char* LODEPNG_VERSION_STRING;
-
-/*
-The following #defines are used to create code sections. They can be disabled
-to disable code sections, which can give faster compile time and smaller binary.
-The "NO_COMPILE" defines are designed to be used to pass as defines to the
-compiler command to disable them without modifying this header, e.g.
--DLODEPNG_NO_COMPILE_ZLIB for gcc.
-In addition to those below, you can also define LODEPNG_NO_COMPILE_CRC to
-allow implementing a custom lodepng_crc32.
-*/
-/*deflate & zlib. If disabled, you must specify alternative zlib functions in
-the custom_zlib field of the compress and decompress settings*/
-#ifndef LODEPNG_NO_COMPILE_ZLIB
-#define LODEPNG_COMPILE_ZLIB
-#endif
-
-/*png encoder and png decoder*/
-#ifndef LODEPNG_NO_COMPILE_PNG
-#define LODEPNG_COMPILE_PNG
-#endif
-
-/*deflate&zlib decoder and png decoder*/
-#ifndef LODEPNG_NO_COMPILE_DECODER
-#define LODEPNG_COMPILE_DECODER
-#endif
-
-/*deflate&zlib encoder and png encoder*/
-#ifndef LODEPNG_NO_COMPILE_ENCODER
-#define LODEPNG_COMPILE_ENCODER
-#endif
-
-/*the optional built in harddisk file loading and saving functions*/
-#ifndef LODEPNG_NO_COMPILE_DISK
-#define LODEPNG_COMPILE_DISK
-#endif
-
-/*support for chunks other than IHDR, IDAT, PLTE, tRNS, IEND: ancillary and unknown chunks*/
-#ifndef LODEPNG_NO_COMPILE_ANCILLARY_CHUNKS
-#define LODEPNG_COMPILE_ANCILLARY_CHUNKS
-#endif
-
-/*ability to convert error numerical codes to English text string*/
-#ifndef LODEPNG_NO_COMPILE_ERROR_TEXT
-#define LODEPNG_COMPILE_ERROR_TEXT
-#endif
-
-/*Compile the default allocators (C's free, malloc and realloc). If you disable this,
-you can define the functions lodepng_free, lodepng_malloc and lodepng_realloc in your
-source files with custom allocators.*/
-#ifndef LODEPNG_NO_COMPILE_ALLOCATORS
-#define LODEPNG_COMPILE_ALLOCATORS
-#endif
-
-/*compile the C++ version (you can disable the C++ wrapper here even when compiling for C++)*/
-#ifdef __cplusplus
-#ifndef LODEPNG_NO_COMPILE_CPP
-#define LODEPNG_COMPILE_CPP
-#endif
-#endif
-
-#ifdef LODEPNG_COMPILE_CPP
-#include <vector>
-#include <string>
-#endif /*LODEPNG_COMPILE_CPP*/
-
-#ifdef LODEPNG_COMPILE_PNG
-/*The PNG color types (also used for raw image).*/
-typedef enum LodePNGColorType {
- LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/
- LCT_RGB = 2, /*RGB: 8,16 bit*/
- LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/
- LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/
- LCT_RGBA = 6, /*RGB with alpha: 8,16 bit*/
- /*LCT_MAX_OCTET_VALUE lets the compiler allow this enum to represent any invalid
- byte value from 0 to 255 that could be present in an invalid PNG file header. Do
- not use, compare with or set the name LCT_MAX_OCTET_VALUE, instead either use
- the valid color type names above, or numeric values like 1 or 7 when checking for
- particular disallowed color type byte values, or cast to integer to print it.*/
- LCT_MAX_OCTET_VALUE = 255
-} LodePNGColorType;
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*
-Converts PNG data in memory to raw pixel data.
-out: Output parameter. Pointer to buffer that will contain the raw pixel data.
- After decoding, its size is w * h * (bytes per pixel) bytes larger than
- initially. Bytes per pixel depends on colortype and bitdepth.
- Must be freed after usage with free(*out).
- Note: for 16-bit per channel colors, uses big endian format like PNG does.
-w: Output parameter. Pointer to width of pixel data.
-h: Output parameter. Pointer to height of pixel data.
-in: Memory buffer with the PNG file.
-insize: size of the in buffer.
-colortype: the desired color type for the raw output image. See explanation on PNG color types.
-bitdepth: the desired bit depth for the raw output image. See explanation on PNG color types.
-Return value: LodePNG error code (0 means no error).
-*/
-unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h,
- const unsigned char* in, size_t insize,
- LodePNGColorType colortype, unsigned bitdepth);
-
-/*Same as lodepng_decode_memory, but always decodes to 32-bit RGBA raw image*/
-unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h,
- const unsigned char* in, size_t insize);
-
-/*Same as lodepng_decode_memory, but always decodes to 24-bit RGB raw image*/
-unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h,
- const unsigned char* in, size_t insize);
-
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Load PNG from disk, from file with given name.
-Same as the other decode functions, but instead takes a filename as input.
-*/
-unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h,
- const char* filename,
- LodePNGColorType colortype, unsigned bitdepth);
-
-/*Same as lodepng_decode_file, but always decodes to 32-bit RGBA raw image.*/
-unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h,
- const char* filename);
-
-/*Same as lodepng_decode_file, but always decodes to 24-bit RGB raw image.*/
-unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h,
- const char* filename);
-#endif /*LODEPNG_COMPILE_DISK*/
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*
-Converts raw pixel data into a PNG image in memory. The colortype and bitdepth
- of the output PNG image cannot be chosen, they are automatically determined
- by the colortype, bitdepth and content of the input pixel data.
- Note: for 16-bit per channel colors, needs big endian format like PNG does.
-out: Output parameter. Pointer to buffer that will contain the PNG image data.
- Must be freed after usage with free(*out).
-outsize: Output parameter. Pointer to the size in bytes of the out buffer.
-image: The raw pixel data to encode. The size of this buffer should be
- w * h * (bytes per pixel), bytes per pixel depends on colortype and bitdepth.
-w: width of the raw pixel data in pixels.
-h: height of the raw pixel data in pixels.
-colortype: the color type of the raw input image. See explanation on PNG color types.
-bitdepth: the bit depth of the raw input image. See explanation on PNG color types.
-Return value: LodePNG error code (0 means no error).
-*/
-unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize,
- const unsigned char* image, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth);
-
-/*Same as lodepng_encode_memory, but always encodes from 32-bit RGBA raw image.*/
-unsigned lodepng_encode32(unsigned char** out, size_t* outsize,
- const unsigned char* image, unsigned w, unsigned h);
-
-/*Same as lodepng_encode_memory, but always encodes from 24-bit RGB raw image.*/
-unsigned lodepng_encode24(unsigned char** out, size_t* outsize,
- const unsigned char* image, unsigned w, unsigned h);
-
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Converts raw pixel data into a PNG file on disk.
-Same as the other encode functions, but instead takes a filename as output.
-NOTE: This overwrites existing files without warning!
-*/
-unsigned lodepng_encode_file(const char* filename,
- const unsigned char* image, unsigned w, unsigned h,
- LodePNGColorType colortype, unsigned bitdepth);
-
-/*Same as lodepng_encode_file, but always encodes from 32-bit RGBA raw image.*/
-unsigned lodepng_encode32_file(const char* filename,
- const unsigned char* image, unsigned w, unsigned h);
-
-/*Same as lodepng_encode_file, but always encodes from 24-bit RGB raw image.*/
-unsigned lodepng_encode24_file(const char* filename,
- const unsigned char* image, unsigned w, unsigned h);
-#endif /*LODEPNG_COMPILE_DISK*/
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-
-#ifdef LODEPNG_COMPILE_CPP
-namespace lodepng {
-#ifdef LODEPNG_COMPILE_DECODER
-/*Same as lodepng_decode_memory, but decodes to an std::vector. The colortype
-is the format to output the pixels to. Default is RGBA 8-bit per channel.*/
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- const unsigned char* in, size_t insize,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- const std::vector<unsigned char>& in,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Converts PNG file from disk to raw pixel data in memory.
-Same as the other decode functions, but instead takes a filename as input.
-*/
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- const std::string& filename,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#endif /* LODEPNG_COMPILE_DISK */
-#endif /* LODEPNG_COMPILE_DECODER */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*Same as lodepng_encode_memory, but encodes to an std::vector. colortype
-is that of the raw input data. The output PNG color type will be auto chosen.*/
-unsigned encode(std::vector<unsigned char>& out,
- const unsigned char* in, unsigned w, unsigned h,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-unsigned encode(std::vector<unsigned char>& out,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Converts 32-bit RGBA raw pixel data into a PNG file on disk.
-Same as the other encode functions, but instead takes a filename as output.
-NOTE: This overwrites existing files without warning!
-*/
-unsigned encode(const std::string& filename,
- const unsigned char* in, unsigned w, unsigned h,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-unsigned encode(const std::string& filename,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8);
-#endif /* LODEPNG_COMPILE_DISK */
-#endif /* LODEPNG_COMPILE_ENCODER */
-} /* namespace lodepng */
-#endif /*LODEPNG_COMPILE_CPP*/
-#endif /*LODEPNG_COMPILE_PNG*/
-
-#ifdef LODEPNG_COMPILE_ERROR_TEXT
-/*Returns an English description of the numerical error code.*/
-const char* lodepng_error_text(unsigned code);
-#endif /*LODEPNG_COMPILE_ERROR_TEXT*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*Settings for zlib decompression*/
-typedef struct LodePNGDecompressSettings LodePNGDecompressSettings;
-struct LodePNGDecompressSettings {
- /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */
- unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/
- unsigned ignore_nlen; /*ignore complement of len checksum in uncompressed blocks*/
-
- /*Maximum decompressed size, beyond this the decoder may (and is encouraged to) stop decoding,
- return an error, output a data size > max_output_size and all the data up to that point. This is
- not hard limit nor a guarantee, but can prevent excessive memory usage. This setting is
- ignored by the PNG decoder, but is used by the deflate/zlib decoder and can be used by custom ones.
- Set to 0 to impose no limit (the default).*/
- size_t max_output_size;
-
- /*use custom zlib decoder instead of built in one (default: null).
- Should return 0 if success, any non-0 if error (numeric value not exposed).*/
- unsigned (*custom_zlib)(unsigned char**, size_t*,
- const unsigned char*, size_t,
- const LodePNGDecompressSettings*);
- /*use custom deflate decoder instead of built in one (default: null)
- if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate).
- Should return 0 if success, any non-0 if error (numeric value not exposed).*/
- unsigned (*custom_inflate)(unsigned char**, size_t*,
- const unsigned char*, size_t,
- const LodePNGDecompressSettings*);
-
- const void* custom_context; /*optional custom settings for custom functions*/
-};
-
-extern const LodePNGDecompressSettings lodepng_default_decompress_settings;
-void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings);
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*
-Settings for zlib compression. Tweaking these settings tweaks the balance
-between speed and compression ratio.
-*/
-typedef struct LodePNGCompressSettings LodePNGCompressSettings;
-struct LodePNGCompressSettings /*deflate = compress*/ {
- /*LZ77 related settings*/
- unsigned btype; /*the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.*/
- unsigned use_lz77; /*whether or not to use LZ77. Should be 1 for proper compression.*/
- unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Default value: 2048.*/
- unsigned minmatch; /*minimum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0*/
- unsigned nicematch; /*stop searching if >= this length found. Set to 258 for best compression. Default: 128*/
- unsigned lazymatching; /*use lazy matching: better compression but a bit slower. Default: true*/
-
- /*use custom zlib encoder instead of built in one (default: null)*/
- unsigned (*custom_zlib)(unsigned char**, size_t*,
- const unsigned char*, size_t,
- const LodePNGCompressSettings*);
- /*use custom deflate encoder instead of built in one (default: null)
- if custom_zlib is used, custom_deflate is ignored since only the built in
- zlib function will call custom_deflate*/
- unsigned (*custom_deflate)(unsigned char**, size_t*,
- const unsigned char*, size_t,
- const LodePNGCompressSettings*);
-
- const void* custom_context; /*optional custom settings for custom functions*/
-};
-
-extern const LodePNGCompressSettings lodepng_default_compress_settings;
-void lodepng_compress_settings_init(LodePNGCompressSettings* settings);
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#ifdef LODEPNG_COMPILE_PNG
-/*
-Color mode of an image. Contains all information required to decode the pixel
-bits to RGBA colors. This information is the same as used in the PNG file
-format, and is used both for PNG and raw image data in LodePNG.
-*/
-typedef struct LodePNGColorMode {
- /*header (IHDR)*/
- LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/
- unsigned bitdepth; /*bits per sample, see PNG standard or documentation further in this header file*/
-
- /*
- palette (PLTE and tRNS)
-
- Dynamically allocated with the colors of the palette, including alpha.
- This field may not be allocated directly, use lodepng_color_mode_init first,
- then lodepng_palette_add per color to correctly initialize it (to ensure size
- of exactly 1024 bytes).
-
- The alpha channels must be set as well, set them to 255 for opaque images.
-
- When decoding, by default you can ignore this palette, since LodePNG already
- fills the palette colors in the pixels of the raw RGBA output.
-
- The palette is only supported for color type 3.
- */
- unsigned char* palette; /*palette in RGBARGBA... order. Must be either 0, or when allocated must have 1024 bytes*/
- size_t palettesize; /*palette size in number of colors (amount of used bytes is 4 * palettesize)*/
-
- /*
- transparent color key (tRNS)
-
- This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit.
- For grayscale PNGs, r, g and b will all 3 be set to the same.
-
- When decoding, by default you can ignore this information, since LodePNG sets
- pixels with this key to transparent already in the raw RGBA output.
-
- The color key is only supported for color types 0 and 2.
- */
- unsigned key_defined; /*is a transparent color key given? 0 = false, 1 = true*/
- unsigned key_r; /*red/grayscale component of color key*/
- unsigned key_g; /*green component of color key*/
- unsigned key_b; /*blue component of color key*/
-} LodePNGColorMode;
-
-/*init, cleanup and copy functions to use with this struct*/
-void lodepng_color_mode_init(LodePNGColorMode* info);
-void lodepng_color_mode_cleanup(LodePNGColorMode* info);
-/*return value is error code (0 means no error)*/
-unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source);
-/* Makes a temporary LodePNGColorMode that does not need cleanup (no palette) */
-LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth);
-
-void lodepng_palette_clear(LodePNGColorMode* info);
-/*add 1 color to the palette*/
-unsigned lodepng_palette_add(LodePNGColorMode* info,
- unsigned char r, unsigned char g, unsigned char b, unsigned char a);
-
-/*get the total amount of bits per pixel, based on colortype and bitdepth in the struct*/
-unsigned lodepng_get_bpp(const LodePNGColorMode* info);
-/*get the amount of color channels used, based on colortype in the struct.
-If a palette is used, it counts as 1 channel.*/
-unsigned lodepng_get_channels(const LodePNGColorMode* info);
-/*is it a grayscale type? (only colortype 0 or 4)*/
-unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info);
-/*has it got an alpha channel? (only colortype 2 or 6)*/
-unsigned lodepng_is_alpha_type(const LodePNGColorMode* info);
-/*has it got a palette? (only colortype 3)*/
-unsigned lodepng_is_palette_type(const LodePNGColorMode* info);
-/*only returns true if there is a palette and there is a value in the palette with alpha < 255.
-Loops through the palette to check this.*/
-unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info);
-/*
-Check if the given color info indicates the possibility of having non-opaque pixels in the PNG image.
-Returns true if the image can have translucent or invisible pixels (it still be opaque if it doesn't use such pixels).
-Returns false if the image can only have opaque pixels.
-In detail, it returns true only if it's a color type with alpha, or has a palette with non-opaque values,
-or if "key_defined" is true.
-*/
-unsigned lodepng_can_have_alpha(const LodePNGColorMode* info);
-/*Returns the byte size of a raw image buffer with given width, height and color mode*/
-size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color);
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-/*The information of a Time chunk in PNG.*/
-typedef struct LodePNGTime {
- unsigned year; /*2 bytes used (0-65535)*/
- unsigned month; /*1-12*/
- unsigned day; /*1-31*/
- unsigned hour; /*0-23*/
- unsigned minute; /*0-59*/
- unsigned second; /*0-60 (to allow for leap seconds)*/
-} LodePNGTime;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-/*Information about the PNG image, except pixels, width and height.*/
-typedef struct LodePNGInfo {
- /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/
- unsigned compression_method;/*compression method of the original file. Always 0.*/
- unsigned filter_method; /*filter method of the original file*/
- unsigned interlace_method; /*interlace method of the original file: 0=none, 1=Adam7*/
- LodePNGColorMode color; /*color type and bits, palette and transparency of the PNG file*/
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*
- Suggested background color chunk (bKGD)
-
- This uses the same color mode and bit depth as the PNG (except no alpha channel),
- with values truncated to the bit depth in the unsigned integer.
-
- For grayscale and palette PNGs, the value is stored in background_r. The values
- in background_g and background_b are then unused.
-
- So when decoding, you may get these in a different color mode than the one you requested
- for the raw pixels.
-
- When encoding with auto_convert, you must use the color model defined in info_png.color for
- these values. The encoder normally ignores info_png.color when auto_convert is on, but will
- use it to interpret these values (and convert copies of them to its chosen color model).
-
- When encoding, avoid setting this to an expensive color, such as a non-gray value
- when the image is gray, or the compression will be worse since it will be forced to
- write the PNG with a more expensive color mode (when auto_convert is on).
-
- The decoder does not use this background color to edit the color of pixels. This is a
- completely optional metadata feature.
- */
- unsigned background_defined; /*is a suggested background color given?*/
- unsigned background_r; /*red/gray/palette component of suggested background color*/
- unsigned background_g; /*green component of suggested background color*/
- unsigned background_b; /*blue component of suggested background color*/
-
- /*
- Non-international text chunks (tEXt and zTXt)
-
- The char** arrays each contain num strings. The actual messages are in
- text_strings, while text_keys are keywords that give a short description what
- the actual text represents, e.g. Title, Author, Description, or anything else.
-
- All the string fields below including strings, keys, names and language tags are null terminated.
- The PNG specification uses null characters for the keys, names and tags, and forbids null
- characters to appear in the main text which is why we can use null termination everywhere here.
-
- A keyword is minimum 1 character and maximum 79 characters long (plus the
- additional null terminator). It's discouraged to use a single line length
- longer than 79 characters for texts.
-
- Don't allocate these text buffers yourself. Use the init/cleanup functions
- correctly and use lodepng_add_text and lodepng_clear_text.
-
- Standard text chunk keywords and strings are encoded using Latin-1.
- */
- size_t text_num; /*the amount of texts in these char** buffers (there may be more texts in itext)*/
- char** text_keys; /*the keyword of a text chunk (e.g. "Comment")*/
- char** text_strings; /*the actual text*/
-
- /*
- International text chunks (iTXt)
- Similar to the non-international text chunks, but with additional strings
- "langtags" and "transkeys", and the following text encodings are used:
- keys: Latin-1, langtags: ASCII, transkeys and strings: UTF-8.
- keys must be 1-79 characters (plus the additional null terminator), the other
- strings are any length.
- */
- size_t itext_num; /*the amount of international texts in this PNG*/
- char** itext_keys; /*the English keyword of the text chunk (e.g. "Comment")*/
- char** itext_langtags; /*language tag for this text's language, ISO/IEC 646 string, e.g. ISO 639 language tag*/
- char** itext_transkeys; /*keyword translated to the international language - UTF-8 string*/
- char** itext_strings; /*the actual international text - UTF-8 string*/
-
- /*time chunk (tIME)*/
- unsigned time_defined; /*set to 1 to make the encoder generate a tIME chunk*/
- LodePNGTime time;
-
- /*phys chunk (pHYs)*/
- unsigned phys_defined; /*if 0, there is no pHYs chunk and the values below are undefined, if 1 else there is one*/
- unsigned phys_x; /*pixels per unit in x direction*/
- unsigned phys_y; /*pixels per unit in y direction*/
- unsigned phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/
-
- /*
- Color profile related chunks: gAMA, cHRM, sRGB, iCPP
-
- LodePNG does not apply any color conversions on pixels in the encoder or decoder and does not interpret these color
- profile values. It merely passes on the information. If you wish to use color profiles and convert colors, please
- use these values with a color management library.
-
- See the PNG, ICC and sRGB specifications for more information about the meaning of these values.
- */
-
- /* gAMA chunk: optional, overridden by sRGB or iCCP if those are present. */
- unsigned gama_defined; /* Whether a gAMA chunk is present (0 = not present, 1 = present). */
- unsigned gama_gamma; /* Gamma exponent times 100000 */
-
- /* cHRM chunk: optional, overridden by sRGB or iCCP if those are present. */
- unsigned chrm_defined; /* Whether a cHRM chunk is present (0 = not present, 1 = present). */
- unsigned chrm_white_x; /* White Point x times 100000 */
- unsigned chrm_white_y; /* White Point y times 100000 */
- unsigned chrm_red_x; /* Red x times 100000 */
- unsigned chrm_red_y; /* Red y times 100000 */
- unsigned chrm_green_x; /* Green x times 100000 */
- unsigned chrm_green_y; /* Green y times 100000 */
- unsigned chrm_blue_x; /* Blue x times 100000 */
- unsigned chrm_blue_y; /* Blue y times 100000 */
-
- /*
- sRGB chunk: optional. May not appear at the same time as iCCP.
- If gAMA is also present gAMA must contain value 45455.
- If cHRM is also present cHRM must contain respectively 31270,32900,64000,33000,30000,60000,15000,6000.
- */
- unsigned srgb_defined; /* Whether an sRGB chunk is present (0 = not present, 1 = present). */
- unsigned srgb_intent; /* Rendering intent: 0=perceptual, 1=rel. colorimetric, 2=saturation, 3=abs. colorimetric */
-
- /*
- iCCP chunk: optional. May not appear at the same time as sRGB.
-
- LodePNG does not parse or use the ICC profile (except its color space header field for an edge case), a
- separate library to handle the ICC data (not included in LodePNG) format is needed to use it for color
- management and conversions.
-
- For encoding, if iCCP is present, gAMA and cHRM are recommended to be added as well with values that match the ICC
- profile as closely as possible, if you wish to do this you should provide the correct values for gAMA and cHRM and
- enable their '_defined' flags since LodePNG will not automatically compute them from the ICC profile.
-
- For encoding, the ICC profile is required by the PNG specification to be an "RGB" profile for non-gray
- PNG color types and a "GRAY" profile for gray PNG color types. If you disable auto_convert, you must ensure
- the ICC profile type matches your requested color type, else the encoder gives an error. If auto_convert is
- enabled (the default), and the ICC profile is not a good match for the pixel data, this will result in an encoder
- error if the pixel data has non-gray pixels for a GRAY profile, or a silent less-optimal compression of the pixel
- data if the pixels could be encoded as grayscale but the ICC profile is RGB.
-
- To avoid this do not set an ICC profile in the image unless there is a good reason for it, and when doing so
- make sure you compute it carefully to avoid the above problems.
- */
- unsigned iccp_defined; /* Whether an iCCP chunk is present (0 = not present, 1 = present). */
- char* iccp_name; /* Null terminated string with profile name, 1-79 bytes */
- /*
- The ICC profile in iccp_profile_size bytes.
- Don't allocate this buffer yourself. Use the init/cleanup functions
- correctly and use lodepng_set_icc and lodepng_clear_icc.
- */
- unsigned char* iccp_profile;
- unsigned iccp_profile_size; /* The size of iccp_profile in bytes */
-
- /* End of color profile related chunks */
-
-
- /*
- unknown chunks: chunks not known by LodePNG, passed on byte for byte.
-
- There are 3 buffers, one for each position in the PNG where unknown chunks can appear.
- Each buffer contains all unknown chunks for that position consecutively.
- The 3 positions are:
- 0: between IHDR and PLTE, 1: between PLTE and IDAT, 2: between IDAT and IEND.
-
- For encoding, do not store critical chunks or known chunks that are enabled with a "_defined" flag
- above in here, since the encoder will blindly follow this and could then encode an invalid PNG file
- (such as one with two IHDR chunks or the disallowed combination of sRGB with iCCP). But do use
- this if you wish to store an ancillary chunk that is not supported by LodePNG (such as sPLT or hIST),
- or any non-standard PNG chunk.
-
- Do not allocate or traverse this data yourself. Use the chunk traversing functions declared
- later, such as lodepng_chunk_next and lodepng_chunk_append, to read/write this struct.
- */
- unsigned char* unknown_chunks_data[3];
- size_t unknown_chunks_size[3]; /*size in bytes of the unknown chunks, given for protection*/
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-} LodePNGInfo;
-
-/*init, cleanup and copy functions to use with this struct*/
-void lodepng_info_init(LodePNGInfo* info);
-void lodepng_info_cleanup(LodePNGInfo* info);
-/*return value is error code (0 means no error)*/
-unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source);
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
-unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str); /*push back both texts at once*/
-void lodepng_clear_text(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/
-
-unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
- const char* transkey, const char* str); /*push back the 4 texts of 1 chunk at once*/
-void lodepng_clear_itext(LodePNGInfo* info); /*use this to clear the itexts again after you filled them in*/
-
-/*replaces if exists*/
-unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size);
-void lodepng_clear_icc(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-
-/*
-Converts raw buffer from one color type to another color type, based on
-LodePNGColorMode structs to describe the input and output color type.
-See the reference manual at the end of this header file to see which color conversions are supported.
-return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported)
-The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel
-of the output color type (lodepng_get_bpp).
-For < 8 bpp images, there should not be padding bits at the end of scanlines.
-For 16-bit per channel colors, uses big endian format like PNG does.
-Return value is LodePNG error code
-*/
-unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
- const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
- unsigned w, unsigned h);
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*
-Settings for the decoder. This contains settings for the PNG and the Zlib
-decoder, but not the Info settings from the Info structs.
-*/
-typedef struct LodePNGDecoderSettings {
- LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/
-
- /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */
- unsigned ignore_crc; /*ignore CRC checksums*/
- unsigned ignore_critical; /*ignore unknown critical chunks*/
- unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/
- /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable
- errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some
- strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters
- in string keys, etc... */
-
- unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/
-
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- unsigned read_text_chunks; /*if false but remember_unknown_chunks is true, they're stored in the unknown chunks*/
-
- /*store all bytes from unknown chunks in the LodePNGInfo (off by default, useful for a png editor)*/
- unsigned remember_unknown_chunks;
-
- /* maximum size for decompressed text chunks. If a text chunk's text is larger than this, an error is returned,
- unless reading text chunks is disabled or this limit is set higher or disabled. Set to 0 to allow any size.
- By default it is a value that prevents unreasonably large strings from hogging memory. */
- size_t max_text_size;
-
- /* maximum size for compressed ICC chunks. If the ICC profile is larger than this, an error will be returned. Set to
- 0 to allow any size. By default this is a value that prevents ICC profiles that would be much larger than any
- legitimate profile could be to hog memory. */
- size_t max_icc_size;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-} LodePNGDecoderSettings;
-
-void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings);
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*automatically use color type with less bits per pixel if losslessly possible. Default: AUTO*/
-typedef enum LodePNGFilterStrategy {
- /*every filter at zero*/
- LFS_ZERO = 0,
- /*every filter at 1, 2, 3 or 4 (paeth), unlike LFS_ZERO not a good choice, but for testing*/
- LFS_ONE = 1,
- LFS_TWO = 2,
- LFS_THREE = 3,
- LFS_FOUR = 4,
- /*Use filter that gives minimum sum, as described in the official PNG filter heuristic.*/
- LFS_MINSUM,
- /*Use the filter type that gives smallest Shannon entropy for this scanline. Depending
- on the image, this is better or worse than minsum.*/
- LFS_ENTROPY,
- /*
- Brute-force-search PNG filters by compressing each filter for each scanline.
- Experimental, very slow, and only rarely gives better compression than MINSUM.
- */
- LFS_BRUTE_FORCE,
- /*use predefined_filters buffer: you specify the filter type for each scanline*/
- LFS_PREDEFINED
-} LodePNGFilterStrategy;
-
-/*Gives characteristics about the integer RGBA colors of the image (count, alpha channel usage, bit depth, ...),
-which helps decide which color model to use for encoding.
-Used internally by default if "auto_convert" is enabled. Public because it's useful for custom algorithms.*/
-typedef struct LodePNGColorStats {
- unsigned colored; /*not grayscale*/
- unsigned key; /*image is not opaque and color key is possible instead of full alpha*/
- unsigned short key_r; /*key values, always as 16-bit, in 8-bit case the byte is duplicated, e.g. 65535 means 255*/
- unsigned short key_g;
- unsigned short key_b;
- unsigned alpha; /*image is not opaque and alpha channel or alpha palette required*/
- unsigned numcolors; /*amount of colors, up to 257. Not valid if bits == 16 or allow_palette is disabled.*/
- unsigned char palette[1024]; /*Remembers up to the first 256 RGBA colors, in no particular order, only valid when numcolors is valid*/
- unsigned bits; /*bits per channel (not for palette). 1,2 or 4 for grayscale only. 16 if 16-bit per channel required.*/
- size_t numpixels;
-
- /*user settings for computing/using the stats*/
- unsigned allow_palette; /*default 1. if 0, disallow choosing palette colortype in auto_choose_color, and don't count numcolors*/
- unsigned allow_greyscale; /*default 1. if 0, choose RGB or RGBA even if the image only has gray colors*/
-} LodePNGColorStats;
-
-void lodepng_color_stats_init(LodePNGColorStats* stats);
-
-/*Get a LodePNGColorStats of the image. The stats must already have been inited.
-Returns error code (e.g. alloc fail) or 0 if ok.*/
-unsigned lodepng_compute_color_stats(LodePNGColorStats* stats,
- const unsigned char* image, unsigned w, unsigned h,
- const LodePNGColorMode* mode_in);
-
-/*Settings for the encoder.*/
-typedef struct LodePNGEncoderSettings {
- LodePNGCompressSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/
-
- unsigned auto_convert; /*automatically choose output PNG color type. Default: true*/
-
- /*If true, follows the official PNG heuristic: if the PNG uses a palette or lower than
- 8 bit depth, set all filters to zero. Otherwise use the filter_strategy. Note that to
- completely follow the official PNG heuristic, filter_palette_zero must be true and
- filter_strategy must be LFS_MINSUM*/
- unsigned filter_palette_zero;
- /*Which filter strategy to use when not using zeroes due to filter_palette_zero.
- Set filter_palette_zero to 0 to ensure always using your chosen strategy. Default: LFS_MINSUM*/
- LodePNGFilterStrategy filter_strategy;
- /*used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with
- the same length as the amount of scanlines in the image, and each value must <= 5. You
- have to cleanup this buffer, LodePNG will never free it. Don't forget that filter_palette_zero
- must be set to 0 to ensure this is also used on palette or low bitdepth images.*/
- const unsigned char* predefined_filters;
-
- /*force creating a PLTE chunk if colortype is 2 or 6 (= a suggested palette).
- If colortype is 3, PLTE is _always_ created.*/
- unsigned force_palette;
-#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
- /*add LodePNG identifier and version as a text chunk, for debugging*/
- unsigned add_id;
- /*encode text chunks as zTXt chunks instead of tEXt chunks, and use compression in iTXt chunks*/
- unsigned text_compression;
-#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
-} LodePNGEncoderSettings;
-
-void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings);
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-
-#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER)
-/*The settings, state and information for extended encoding and decoding.*/
-typedef struct LodePNGState {
-#ifdef LODEPNG_COMPILE_DECODER
- LodePNGDecoderSettings decoder; /*the decoding settings*/
-#endif /*LODEPNG_COMPILE_DECODER*/
-#ifdef LODEPNG_COMPILE_ENCODER
- LodePNGEncoderSettings encoder; /*the encoding settings*/
-#endif /*LODEPNG_COMPILE_ENCODER*/
- LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/
- LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/
- unsigned error;
-} LodePNGState;
-
-/*init, cleanup and copy functions to use with this struct*/
-void lodepng_state_init(LodePNGState* state);
-void lodepng_state_cleanup(LodePNGState* state);
-void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source);
-#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*
-Same as lodepng_decode_memory, but uses a LodePNGState to allow custom settings and
-getting much more information about the PNG image and color mode.
-*/
-unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h,
- LodePNGState* state,
- const unsigned char* in, size_t insize);
-
-/*
-Read the PNG header, but not the actual data. This returns only the information
-that is in the IHDR chunk of the PNG, such as width, height and color type. The
-information is placed in the info_png field of the LodePNGState.
-*/
-unsigned lodepng_inspect(unsigned* w, unsigned* h,
- LodePNGState* state,
- const unsigned char* in, size_t insize);
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-/*
-Reads one metadata chunk (other than IHDR) of the PNG file and outputs what it
-read in the state. Returns error code on failure.
-Use lodepng_inspect first with a new state, then e.g. lodepng_chunk_find_const
-to find the desired chunk type, and if non null use lodepng_inspect_chunk (with
-chunk_pointer - start_of_file as pos).
-Supports most metadata chunks from the PNG standard (gAMA, bKGD, tEXt, ...).
-Ignores unsupported, unknown, non-metadata or IHDR chunks (without error).
-Requirements: &in[pos] must point to start of a chunk, must use regular
-lodepng_inspect first since format of most other chunks depends on IHDR, and if
-there is a PLTE chunk, that one must be inspected before tRNS or bKGD.
-*/
-unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos,
- const unsigned char* in, size_t insize);
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*This function allocates the out buffer with standard malloc and stores the size in *outsize.*/
-unsigned lodepng_encode(unsigned char** out, size_t* outsize,
- const unsigned char* image, unsigned w, unsigned h,
- LodePNGState* state);
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-/*
-The lodepng_chunk functions are normally not needed, except to traverse the
-unknown chunks stored in the LodePNGInfo struct, or add new ones to it.
-It also allows traversing the chunks of an encoded PNG file yourself.
-
-The chunk pointer always points to the beginning of the chunk itself, that is
-the first byte of the 4 length bytes.
-
-In the PNG file format, chunks have the following format:
--4 bytes length: length of the data of the chunk in bytes (chunk itself is 12 bytes longer)
--4 bytes chunk type (ASCII a-z,A-Z only, see below)
--length bytes of data (may be 0 bytes if length was 0)
--4 bytes of CRC, computed on chunk name + data
-
-The first chunk starts at the 8th byte of the PNG file, the entire rest of the file
-exists out of concatenated chunks with the above format.
-
-PNG standard chunk ASCII naming conventions:
--First byte: uppercase = critical, lowercase = ancillary
--Second byte: uppercase = public, lowercase = private
--Third byte: must be uppercase
--Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy
-*/
-
-/*
-Gets the length of the data of the chunk. Total chunk length has 12 bytes more.
-There must be at least 4 bytes to read from. If the result value is too large,
-it may be corrupt data.
-*/
-unsigned lodepng_chunk_length(const unsigned char* chunk);
-
-/*puts the 4-byte type in null terminated string*/
-void lodepng_chunk_type(char type[5], const unsigned char* chunk);
-
-/*check if the type is the given type*/
-unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type);
-
-/*0: it's one of the critical chunk types, 1: it's an ancillary chunk (see PNG standard)*/
-unsigned char lodepng_chunk_ancillary(const unsigned char* chunk);
-
-/*0: public, 1: private (see PNG standard)*/
-unsigned char lodepng_chunk_private(const unsigned char* chunk);
-
-/*0: the chunk is unsafe to copy, 1: the chunk is safe to copy (see PNG standard)*/
-unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk);
-
-/*get pointer to the data of the chunk, where the input points to the header of the chunk*/
-unsigned char* lodepng_chunk_data(unsigned char* chunk);
-const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk);
-
-/*returns 0 if the crc is correct, 1 if it's incorrect (0 for OK as usual!)*/
-unsigned lodepng_chunk_check_crc(const unsigned char* chunk);
-
-/*generates the correct CRC from the data and puts it in the last 4 bytes of the chunk*/
-void lodepng_chunk_generate_crc(unsigned char* chunk);
-
-/*
-Iterate to next chunks, allows iterating through all chunks of the PNG file.
-Input must be at the beginning of a chunk (result of a previous lodepng_chunk_next call,
-or the 8th byte of a PNG file which always has the first chunk), or alternatively may
-point to the first byte of the PNG file (which is not a chunk but the magic header, the
-function will then skip over it and return the first real chunk).
-Will output pointer to the start of the next chunk, or at or beyond end of the file if there
-is no more chunk after this or possibly if the chunk is corrupt.
-Start this process at the 8th byte of the PNG file.
-In a non-corrupt PNG file, the last chunk should have name "IEND".
-*/
-unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end);
-const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end);
-
-/*Finds the first chunk with the given type in the range [chunk, end), or returns NULL if not found.*/
-unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]);
-const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]);
-
-/*
-Appends chunk to the data in out. The given chunk should already have its chunk header.
-The out variable and outsize are updated to reflect the new reallocated buffer.
-Returns error code (0 if it went ok)
-*/
-unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk);
-
-/*
-Appends new chunk to out. The chunk to append is given by giving its length, type
-and data separately. The type is a 4-letter string.
-The out variable and outsize are updated to reflect the new reallocated buffer.
-Returne error code (0 if it went ok)
-*/
-unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, unsigned length,
- const char* type, const unsigned char* data);
-
-
-/*Calculate CRC32 of buffer*/
-unsigned lodepng_crc32(const unsigned char* buf, size_t len);
-#endif /*LODEPNG_COMPILE_PNG*/
-
-
-#ifdef LODEPNG_COMPILE_ZLIB
-/*
-This zlib part can be used independently to zlib compress and decompress a
-buffer. It cannot be used to create gzip files however, and it only supports the
-part of zlib that is required for PNG, it does not support dictionaries.
-*/
-
-#ifdef LODEPNG_COMPILE_DECODER
-/*Inflate a buffer. Inflate is the decompression step of deflate. Out buffer must be freed after use.*/
-unsigned lodepng_inflate(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings);
-
-/*
-Decompresses Zlib data. Reallocates the out buffer and appends the data. The
-data must be according to the zlib specification.
-Either, *out must be NULL and *outsize must be 0, or, *out must be a valid
-buffer and *outsize its size in bytes. out must be freed by user after usage.
-*/
-unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings* settings);
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/*
-Compresses data with Zlib. Reallocates the out buffer and appends the data.
-Zlib adds a small header and trailer around the deflate data.
-The data is output in the format of the zlib specification.
-Either, *out must be NULL and *outsize must be 0, or, *out must be a valid
-buffer and *outsize its size in bytes. out must be freed by user after usage.
-*/
-unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGCompressSettings* settings);
-
-/*
-Find length-limited Huffman code for given frequencies. This function is in the
-public interface only for tests, it's used internally by lodepng_deflate.
-*/
-unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
- size_t numcodes, unsigned maxbitlen);
-
-/*Compress a buffer with deflate. See RFC 1951. Out buffer must be freed after use.*/
-unsigned lodepng_deflate(unsigned char** out, size_t* outsize,
- const unsigned char* in, size_t insize,
- const LodePNGCompressSettings* settings);
-
-#endif /*LODEPNG_COMPILE_ENCODER*/
-#endif /*LODEPNG_COMPILE_ZLIB*/
-
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Load a file from disk into buffer. The function allocates the out buffer, and
-after usage you should free it.
-out: output parameter, contains pointer to loaded buffer.
-outsize: output parameter, size of the allocated out buffer
-filename: the path to the file to load
-return value: error code (0 means ok)
-*/
-unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename);
-
-/*
-Save a file from buffer to disk. Warning, if it exists, this function overwrites
-the file without warning!
-buffer: the buffer to write
-buffersize: size of the buffer to write
-filename: the path to the file to save to
-return value: error code (0 means ok)
-*/
-unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename);
-#endif /*LODEPNG_COMPILE_DISK*/
-
-#ifdef LODEPNG_COMPILE_CPP
-/* The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers. */
-namespace lodepng {
-#ifdef LODEPNG_COMPILE_PNG
-class State : public LodePNGState {
- public:
- State();
- State(const State& other);
- ~State();
- State& operator=(const State& other);
-};
-
-#ifdef LODEPNG_COMPILE_DECODER
-/* Same as other lodepng::decode, but using a State for more settings and information. */
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- State& state,
- const unsigned char* in, size_t insize);
-unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
- State& state,
- const std::vector<unsigned char>& in);
-#endif /*LODEPNG_COMPILE_DECODER*/
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/* Same as other lodepng::encode, but using a State for more settings and information. */
-unsigned encode(std::vector<unsigned char>& out,
- const unsigned char* in, unsigned w, unsigned h,
- State& state);
-unsigned encode(std::vector<unsigned char>& out,
- const std::vector<unsigned char>& in, unsigned w, unsigned h,
- State& state);
-#endif /*LODEPNG_COMPILE_ENCODER*/
-
-#ifdef LODEPNG_COMPILE_DISK
-/*
-Load a file from disk into an std::vector.
-return value: error code (0 means ok)
-*/
-unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename);
-
-/*
-Save the binary data in an std::vector to a file on disk. The file is overwritten
-without warning.
-*/
-unsigned save_file(const std::vector<unsigned char>& buffer, const std::string& filename);
-#endif /* LODEPNG_COMPILE_DISK */
-#endif /* LODEPNG_COMPILE_PNG */
-
-#ifdef LODEPNG_COMPILE_ZLIB
-#ifdef LODEPNG_COMPILE_DECODER
-/* Zlib-decompress an unsigned char buffer */
-unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
- const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
-
-/* Zlib-decompress an std::vector */
-unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
- const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings);
-#endif /* LODEPNG_COMPILE_DECODER */
-
-#ifdef LODEPNG_COMPILE_ENCODER
-/* Zlib-compress an unsigned char buffer */
-unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
- const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
-
-/* Zlib-compress an std::vector */
-unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
- const LodePNGCompressSettings& settings = lodepng_default_compress_settings);
-#endif /* LODEPNG_COMPILE_ENCODER */
-#endif /* LODEPNG_COMPILE_ZLIB */
-} /* namespace lodepng */
-#endif /*LODEPNG_COMPILE_CPP*/
-
-/*
-TODO:
-[.] test if there are no memory leaks or security exploits - done a lot but needs to be checked often
-[.] check compatibility with various compilers - done but needs to be redone for every newer version
-[X] converting color to 16-bit per channel types
-[X] support color profile chunk types (but never let them touch RGB values by default)
-[ ] support all public PNG chunk types (almost done except sBIT, sPLT and hIST)
-[ ] make sure encoder generates no chunks with size > (2^31)-1
-[ ] partial decoding (stream processing)
-[X] let the "isFullyOpaque" function check color keys and transparent palettes too
-[X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl"
-[ ] allow treating some errors like warnings, when image is recoverable (e.g. 69, 57, 58)
-[ ] make warnings like: oob palette, checksum fail, data after iend, wrong/unknown crit chunk, no null terminator in text, ...
-[ ] error messages with line numbers (and version)
-[ ] errors in state instead of as return code?
-[ ] new errors/warnings like suspiciously big decompressed ztxt or iccp chunk
-[ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes
-[ ] allow user to provide custom color conversion functions, e.g. for premultiplied alpha, padding bits or not, ...
-[ ] allow user to give data (void*) to custom allocator
-[X] provide alternatives for C library functions not present on some platforms (memcpy, ...)
-*/
-
-#endif /*LODEPNG_H inclusion guard*/
-
-/*
-LodePNG Documentation
----------------------
-
-0. table of contents
---------------------
-
- 1. about
- 1.1. supported features
- 1.2. features not supported
- 2. C and C++ version
- 3. security
- 4. decoding
- 5. encoding
- 6. color conversions
- 6.1. PNG color types
- 6.2. color conversions
- 6.3. padding bits
- 6.4. A note about 16-bits per channel and endianness
- 7. error values
- 8. chunks and PNG editing
- 9. compiler support
- 10. examples
- 10.1. decoder C++ example
- 10.2. decoder C example
- 11. state settings reference
- 12. changes
- 13. contact information
-
-
-1. about
---------
-
-PNG is a file format to store raster images losslessly with good compression,
-supporting different color types and alpha channel.
-
-LodePNG is a PNG codec according to the Portable Network Graphics (PNG)
-Specification (Second Edition) - W3C Recommendation 10 November 2003.
-
-The specifications used are:
-
-*) Portable Network Graphics (PNG) Specification (Second Edition):
- http://www.w3.org/TR/2003/REC-PNG-20031110
-*) RFC 1950 ZLIB Compressed Data Format version 3.3:
- http://www.gzip.org/zlib/rfc-zlib.html
-*) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3:
- http://www.gzip.org/zlib/rfc-deflate.html
-
-The most recent version of LodePNG can currently be found at
-http://lodev.org/lodepng/
-
-LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds
-extra functionality.
-
-LodePNG exists out of two files:
--lodepng.h: the header file for both C and C++
--lodepng.c(pp): give it the name lodepng.c or lodepng.cpp (or .cc) depending on your usage
-
-If you want to start using LodePNG right away without reading this doc, get the
-examples from the LodePNG website to see how to use it in code, or check the
-smaller examples in chapter 13 here.
-
-LodePNG is simple but only supports the basic requirements. To achieve
-simplicity, the following design choices were made: There are no dependencies
-on any external library. There are functions to decode and encode a PNG with
-a single function call, and extended versions of these functions taking a
-LodePNGState struct allowing to specify or get more information. By default
-the colors of the raw image are always RGB or RGBA, no matter what color type
-the PNG file uses. To read and write files, there are simple functions to
-convert the files to/from buffers in memory.
-
-This all makes LodePNG suitable for loading textures in games, demos and small
-programs, ... It's less suitable for full fledged image editors, loading PNGs
-over network (it requires all the image data to be available before decoding can
-begin), life-critical systems, ...
-
-1.1. supported features
------------------------
-
-The following features are supported by the decoder:
-
-*) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image,
- or the same color type as the PNG
-*) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image
-*) Adam7 interlace and deinterlace for any color type
-*) loading the image from harddisk or decoding it from a buffer from other sources than harddisk
-*) support for alpha channels, including RGBA color model, translucent palettes and color keying
-*) zlib decompression (inflate)
-*) zlib compression (deflate)
-*) CRC32 and ADLER32 checksums
-*) colorimetric color profile conversions: currently experimentally available in lodepng_util.cpp only,
- plus alternatively ability to pass on chroma/gamma/ICC profile information to other color management system.
-*) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks.
-*) the following chunks are supported by both encoder and decoder:
- IHDR: header information
- PLTE: color palette
- IDAT: pixel data
- IEND: the final chunk
- tRNS: transparency for palettized images
- tEXt: textual information
- zTXt: compressed textual information
- iTXt: international textual information
- bKGD: suggested background color
- pHYs: physical dimensions
- tIME: modification time
- cHRM: RGB chromaticities
- gAMA: RGB gamma correction
- iCCP: ICC color profile
- sRGB: rendering intent
-
-1.2. features not supported
----------------------------
-
-The following features are _not_ supported:
-
-*) some features needed to make a conformant PNG-Editor might be still missing.
-*) partial loading/stream processing. All data must be available and is processed in one call.
-*) The following public chunks are not (yet) supported but treated as unknown chunks by LodePNG:
- sBIT
- hIST
- sPLT
-
-
-2. C and C++ version
---------------------
-
-The C version uses buffers allocated with alloc that you need to free()
-yourself. You need to use init and cleanup functions for each struct whenever
-using a struct from the C version to avoid exploits and memory leaks.
-
-The C++ version has extra functions with std::vectors in the interface and the
-lodepng::State class which is a LodePNGState with constructor and destructor.
-
-These files work without modification for both C and C++ compilers because all
-the additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers
-ignore it, and the C code is made to compile both with strict ISO C90 and C++.
-
-To use the C++ version, you need to rename the source file to lodepng.cpp
-(instead of lodepng.c), and compile it with a C++ compiler.
-
-To use the C version, you need to rename the source file to lodepng.c (instead
-of lodepng.cpp), and compile it with a C compiler.
-
-
-3. Security
------------
-
-Even if carefully designed, it's always possible that LodePNG contains possible
-exploits. If you discover one, please let me know, and it will be fixed.
-
-When using LodePNG, care has to be taken with the C version of LodePNG, as well
-as the C-style structs when working with C++. The following conventions are used
-for all C-style structs:
-
--if a struct has a corresponding init function, always call the init function when making a new one
--if a struct has a corresponding cleanup function, call it before the struct disappears to avoid memory leaks
--if a struct has a corresponding copy function, use the copy function instead of "=".
- The destination must also be inited already.
-
-
-4. Decoding
------------
-
-Decoding converts a PNG compressed image to a raw pixel buffer.
-
-Most documentation on using the decoder is at its declarations in the header
-above. For C, simple decoding can be done with functions such as
-lodepng_decode32, and more advanced decoding can be done with the struct
-LodePNGState and lodepng_decode. For C++, all decoding can be done with the
-various lodepng::decode functions, and lodepng::State can be used for advanced
-features.
-
-When using the LodePNGState, it uses the following fields for decoding:
-*) LodePNGInfo info_png: it stores extra information about the PNG (the input) in here
-*) LodePNGColorMode info_raw: here you can say what color mode of the raw image (the output) you want to get
-*) LodePNGDecoderSettings decoder: you can specify a few extra settings for the decoder to use
-
-LodePNGInfo info_png
---------------------
-
-After decoding, this contains extra information of the PNG image, except the actual
-pixels, width and height because these are already gotten directly from the decoder
-functions.
-
-It contains for example the original color type of the PNG image, text comments,
-suggested background color, etc... More details about the LodePNGInfo struct are
-at its declaration documentation.
-
-LodePNGColorMode info_raw
--------------------------
-
-When decoding, here you can specify which color type you want
-the resulting raw image to be. If this is different from the colortype of the
-PNG, then the decoder will automatically convert the result. This conversion
-always works, except if you want it to convert a color PNG to grayscale or to
-a palette with missing colors.
-
-By default, 32-bit color is used for the result.
-
-LodePNGDecoderSettings decoder
-------------------------------
-
-The settings can be used to ignore the errors created by invalid CRC and Adler32
-chunks, and to disable the decoding of tEXt chunks.
-
-There's also a setting color_convert, true by default. If false, no conversion
-is done, the resulting data will be as it was in the PNG (after decompression)
-and you'll have to puzzle the colors of the pixels together yourself using the
-color type information in the LodePNGInfo.
-
-
-5. Encoding
------------
-
-Encoding converts a raw pixel buffer to a PNG compressed image.
-
-Most documentation on using the encoder is at its declarations in the header
-above. For C, simple encoding can be done with functions such as
-lodepng_encode32, and more advanced decoding can be done with the struct
-LodePNGState and lodepng_encode. For C++, all encoding can be done with the
-various lodepng::encode functions, and lodepng::State can be used for advanced
-features.
-
-Like the decoder, the encoder can also give errors. However it gives less errors
-since the encoder input is trusted, the decoder input (a PNG image that could
-be forged by anyone) is not trusted.
-
-When using the LodePNGState, it uses the following fields for encoding:
-*) LodePNGInfo info_png: here you specify how you want the PNG (the output) to be.
-*) LodePNGColorMode info_raw: here you say what color type of the raw image (the input) has
-*) LodePNGEncoderSettings encoder: you can specify a few settings for the encoder to use
-
-LodePNGInfo info_png
---------------------
-
-When encoding, you use this the opposite way as when decoding: for encoding,
-you fill in the values you want the PNG to have before encoding. By default it's
-not needed to specify a color type for the PNG since it's automatically chosen,
-but it's possible to choose it yourself given the right settings.
-
-The encoder will not always exactly match the LodePNGInfo struct you give,
-it tries as close as possible. Some things are ignored by the encoder. The
-encoder uses, for example, the following settings from it when applicable:
-colortype and bitdepth, text chunks, time chunk, the color key, the palette, the
-background color, the interlace method, unknown chunks, ...
-
-When encoding to a PNG with colortype 3, the encoder will generate a PLTE chunk.
-If the palette contains any colors for which the alpha channel is not 255 (so
-there are translucent colors in the palette), it'll add a tRNS chunk.
-
-LodePNGColorMode info_raw
--------------------------
-
-You specify the color type of the raw image that you give to the input here,
-including a possible transparent color key and palette you happen to be using in
-your raw image data.
-
-By default, 32-bit color is assumed, meaning your input has to be in RGBA
-format with 4 bytes (unsigned chars) per pixel.
-
-LodePNGEncoderSettings encoder
-------------------------------
-
-The following settings are supported (some are in sub-structs):
-*) auto_convert: when this option is enabled, the encoder will
-automatically choose the smallest possible color mode (including color key) that
-can encode the colors of all pixels without information loss.
-*) btype: the block type for LZ77. 0 = uncompressed, 1 = fixed huffman tree,
- 2 = dynamic huffman tree (best compression). Should be 2 for proper
- compression.
-*) use_lz77: whether or not to use LZ77 for compressed block types. Should be
- true for proper compression.
-*) windowsize: the window size used by the LZ77 encoder (1 - 32768). Has value
- 2048 by default, but can be set to 32768 for better, but slow, compression.
-*) force_palette: if colortype is 2 or 6, you can make the encoder write a PLTE
- chunk if force_palette is true. This can used as suggested palette to convert
- to by viewers that don't support more than 256 colors (if those still exist)
-*) add_id: add text chunk "Encoder: LodePNG <version>" to the image.
-*) text_compression: default 1. If 1, it'll store texts as zTXt instead of tEXt chunks.
- zTXt chunks use zlib compression on the text. This gives a smaller result on
- large texts but a larger result on small texts (such as a single program name).
- It's all tEXt or all zTXt though, there's no separate setting per text yet.
-
-
-6. color conversions
---------------------
-
-An important thing to note about LodePNG, is that the color type of the PNG, and
-the color type of the raw image, are completely independent. By default, when
-you decode a PNG, you get the result as a raw image in the color type you want,
-no matter whether the PNG was encoded with a palette, grayscale or RGBA color.
-And if you encode an image, by default LodePNG will automatically choose the PNG
-color type that gives good compression based on the values of colors and amount
-of colors in the image. It can be configured to let you control it instead as
-well, though.
-
-To be able to do this, LodePNG does conversions from one color mode to another.
-It can convert from almost any color type to any other color type, except the
-following conversions: RGB to grayscale is not supported, and converting to a
-palette when the palette doesn't have a required color is not supported. This is
-not supported on purpose: this is information loss which requires a color
-reduction algorithm that is beyond the scope of a PNG encoder (yes, RGB to gray
-is easy, but there are multiple ways if you want to give some channels more
-weight).
-
-By default, when decoding, you get the raw image in 32-bit RGBA or 24-bit RGB
-color, no matter what color type the PNG has. And by default when encoding,
-LodePNG automatically picks the best color model for the output PNG, and expects
-the input image to be 32-bit RGBA or 24-bit RGB. So, unless you want to control
-the color format of the images yourself, you can skip this chapter.
-
-6.1. PNG color types
---------------------
-
-A PNG image can have many color types, ranging from 1-bit color to 64-bit color,
-as well as palettized color modes. After the zlib decompression and unfiltering
-in the PNG image is done, the raw pixel data will have that color type and thus
-a certain amount of bits per pixel. If you want the output raw image after
-decoding to have another color type, a conversion is done by LodePNG.
-
-The PNG specification gives the following color types:
-
-0: grayscale, bit depths 1, 2, 4, 8, 16
-2: RGB, bit depths 8 and 16
-3: palette, bit depths 1, 2, 4 and 8
-4: grayscale with alpha, bit depths 8 and 16
-6: RGBA, bit depths 8 and 16
-
-Bit depth is the amount of bits per pixel per color channel. So the total amount
-of bits per pixel is: amount of channels * bitdepth.
-
-6.2. color conversions
-----------------------
-
-As explained in the sections about the encoder and decoder, you can specify
-color types and bit depths in info_png and info_raw to change the default
-behaviour.
-
-If, when decoding, you want the raw image to be something else than the default,
-you need to set the color type and bit depth you want in the LodePNGColorMode,
-or the parameters colortype and bitdepth of the simple decoding function.
-
-If, when encoding, you use another color type than the default in the raw input
-image, you need to specify its color type and bit depth in the LodePNGColorMode
-of the raw image, or use the parameters colortype and bitdepth of the simple
-encoding function.
-
-If, when encoding, you don't want LodePNG to choose the output PNG color type
-but control it yourself, you need to set auto_convert in the encoder settings
-to false, and specify the color type you want in the LodePNGInfo of the
-encoder (including palette: it can generate a palette if auto_convert is true,
-otherwise not).
-
-If the input and output color type differ (whether user chosen or auto chosen),
-LodePNG will do a color conversion, which follows the rules below, and may
-sometimes result in an error.
-
-To avoid some confusion:
--the decoder converts from PNG to raw image
--the encoder converts from raw image to PNG
--the colortype and bitdepth in LodePNGColorMode info_raw, are those of the raw image
--the colortype and bitdepth in the color field of LodePNGInfo info_png, are those of the PNG
--when encoding, the color type in LodePNGInfo is ignored if auto_convert
- is enabled, it is automatically generated instead
--when decoding, the color type in LodePNGInfo is set by the decoder to that of the original
- PNG image, but it can be ignored since the raw image has the color type you requested instead
--if the color type of the LodePNGColorMode and PNG image aren't the same, a conversion
- between the color types is done if the color types are supported. If it is not
- supported, an error is returned. If the types are the same, no conversion is done.
--even though some conversions aren't supported, LodePNG supports loading PNGs from any
- colortype and saving PNGs to any colortype, sometimes it just requires preparing
- the raw image correctly before encoding.
--both encoder and decoder use the same color converter.
-
-The function lodepng_convert does the color conversion. It is available in the
-interface but normally isn't needed since the encoder and decoder already call
-it.
-
-Non supported color conversions:
--color to grayscale when non-gray pixels are present: no error is thrown, but
-the result will look ugly because only the red channel is taken (it assumes all
-three channels are the same in this case so ignores green and blue). The reason
-no error is given is to allow converting from three-channel grayscale images to
-one-channel even if there are numerical imprecisions.
--anything to palette when the palette does not have an exact match for a from-color
-in it: in this case an error is thrown
-
-Supported color conversions:
--anything to 8-bit RGB, 8-bit RGBA, 16-bit RGB, 16-bit RGBA
--any gray or gray+alpha, to gray or gray+alpha
--anything to a palette, as long as the palette has the requested colors in it
--removing alpha channel
--higher to smaller bitdepth, and vice versa
-
-If you want no color conversion to be done (e.g. for speed or control):
--In the encoder, you can make it save a PNG with any color type by giving the
-raw color mode and LodePNGInfo the same color mode, and setting auto_convert to
-false.
--In the decoder, you can make it store the pixel data in the same color type
-as the PNG has, by setting the color_convert setting to false. Settings in
-info_raw are then ignored.
-
-6.3. padding bits
------------------
-
-In the PNG file format, if a less than 8-bit per pixel color type is used and the scanlines
-have a bit amount that isn't a multiple of 8, then padding bits are used so that each
-scanline starts at a fresh byte. But that is NOT true for the LodePNG raw input and output.
-The raw input image you give to the encoder, and the raw output image you get from the decoder
-will NOT have these padding bits, e.g. in the case of a 1-bit image with a width
-of 7 pixels, the first pixel of the second scanline will the 8th bit of the first byte,
-not the first bit of a new byte.
-
-6.4. A note about 16-bits per channel and endianness
-----------------------------------------------------
-
-LodePNG uses unsigned char arrays for 16-bit per channel colors too, just like
-for any other color format. The 16-bit values are stored in big endian (most
-significant byte first) in these arrays. This is the opposite order of the
-little endian used by x86 CPU's.
-
-LodePNG always uses big endian because the PNG file format does so internally.
-Conversions to other formats than PNG uses internally are not supported by
-LodePNG on purpose, there are myriads of formats, including endianness of 16-bit
-colors, the order in which you store R, G, B and A, and so on. Supporting and
-converting to/from all that is outside the scope of LodePNG.
-
-This may mean that, depending on your use case, you may want to convert the big
-endian output of LodePNG to little endian with a for loop. This is certainly not
-always needed, many applications and libraries support big endian 16-bit colors
-anyway, but it means you cannot simply cast the unsigned char* buffer to an
-unsigned short* buffer on x86 CPUs.
-
-
-7. error values
----------------
-
-All functions in LodePNG that return an error code, return 0 if everything went
-OK, or a non-zero code if there was an error.
-
-The meaning of the LodePNG error values can be retrieved with the function
-lodepng_error_text: given the numerical error code, it returns a description
-of the error in English as a string.
-
-Check the implementation of lodepng_error_text to see the meaning of each code.
-
-It is not recommended to use the numerical values to programmatically make
-different decisions based on error types as the numbers are not guaranteed to
-stay backwards compatible. They are for human consumption only. Programmatically
-only 0 or non-0 matter.
-
-
-8. chunks and PNG editing
--------------------------
-
-If you want to add extra chunks to a PNG you encode, or use LodePNG for a PNG
-editor that should follow the rules about handling of unknown chunks, or if your
-program is able to read other types of chunks than the ones handled by LodePNG,
-then that's possible with the chunk functions of LodePNG.
-
-A PNG chunk has the following layout:
-
-4 bytes length
-4 bytes type name
-length bytes data
-4 bytes CRC
-
-8.1. iterating through chunks
------------------------------
-
-If you have a buffer containing the PNG image data, then the first chunk (the
-IHDR chunk) starts at byte number 8 of that buffer. The first 8 bytes are the
-signature of the PNG and are not part of a chunk. But if you start at byte 8
-then you have a chunk, and can check the following things of it.
-
-NOTE: none of these functions check for memory buffer boundaries. To avoid
-exploits, always make sure the buffer contains all the data of the chunks.
-When using lodepng_chunk_next, make sure the returned value is within the
-allocated memory.
-
-unsigned lodepng_chunk_length(const unsigned char* chunk):
-
-Get the length of the chunk's data. The total chunk length is this length + 12.
-
-void lodepng_chunk_type(char type[5], const unsigned char* chunk):
-unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type):
-
-Get the type of the chunk or compare if it's a certain type
-
-unsigned char lodepng_chunk_critical(const unsigned char* chunk):
-unsigned char lodepng_chunk_private(const unsigned char* chunk):
-unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk):
-
-Check if the chunk is critical in the PNG standard (only IHDR, PLTE, IDAT and IEND are).
-Check if the chunk is private (public chunks are part of the standard, private ones not).
-Check if the chunk is safe to copy. If it's not, then, when modifying data in a critical
-chunk, unsafe to copy chunks of the old image may NOT be saved in the new one if your
-program doesn't handle that type of unknown chunk.
-
-unsigned char* lodepng_chunk_data(unsigned char* chunk):
-const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk):
-
-Get a pointer to the start of the data of the chunk.
-
-unsigned lodepng_chunk_check_crc(const unsigned char* chunk):
-void lodepng_chunk_generate_crc(unsigned char* chunk):
-
-Check if the crc is correct or generate a correct one.
-
-unsigned char* lodepng_chunk_next(unsigned char* chunk):
-const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk):
-
-Iterate to the next chunk. This works if you have a buffer with consecutive chunks. Note that these
-functions do no boundary checking of the allocated data whatsoever, so make sure there is enough
-data available in the buffer to be able to go to the next chunk.
-
-unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk):
-unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, unsigned length,
- const char* type, const unsigned char* data):
-
-These functions are used to create new chunks that are appended to the data in *out that has
-length *outsize. The append function appends an existing chunk to the new data. The create
-function creates a new chunk with the given parameters and appends it. Type is the 4-letter
-name of the chunk.
-
-8.2. chunks in info_png
------------------------
-
-The LodePNGInfo struct contains fields with the unknown chunk in it. It has 3
-buffers (each with size) to contain 3 types of unknown chunks:
-the ones that come before the PLTE chunk, the ones that come between the PLTE
-and the IDAT chunks, and the ones that come after the IDAT chunks.
-It's necessary to make the distinction between these 3 cases because the PNG
-standard forces to keep the ordering of unknown chunks compared to the critical
-chunks, but does not force any other ordering rules.
-
-info_png.unknown_chunks_data[0] is the chunks before PLTE
-info_png.unknown_chunks_data[1] is the chunks after PLTE, before IDAT
-info_png.unknown_chunks_data[2] is the chunks after IDAT
-
-The chunks in these 3 buffers can be iterated through and read by using the same
-way described in the previous subchapter.
-
-When using the decoder to decode a PNG, you can make it store all unknown chunks
-if you set the option settings.remember_unknown_chunks to 1. By default, this
-option is off (0).
-
-The encoder will always encode unknown chunks that are stored in the info_png.
-If you need it to add a particular chunk that isn't known by LodePNG, you can
-use lodepng_chunk_append or lodepng_chunk_create to the chunk data in
-info_png.unknown_chunks_data[x].
-
-Chunks that are known by LodePNG should not be added in that way. E.g. to make
-LodePNG add a bKGD chunk, set background_defined to true and add the correct
-parameters there instead.
-
-
-9. compiler support
--------------------
-
-No libraries other than the current standard C library are needed to compile
-LodePNG. For the C++ version, only the standard C++ library is needed on top.
-Add the files lodepng.c(pp) and lodepng.h to your project, include
-lodepng.h where needed, and your program can read/write PNG files.
-
-It is compatible with C90 and up, and C++03 and up.
-
-If performance is important, use optimization when compiling! For both the
-encoder and decoder, this makes a large difference.
-
-Make sure that LodePNG is compiled with the same compiler of the same version
-and with the same settings as the rest of the program, or the interfaces with
-std::vectors and std::strings in C++ can be incompatible.
-
-CHAR_BITS must be 8 or higher, because LodePNG uses unsigned chars for octets.
-
-*) gcc and g++
-
-LodePNG is developed in gcc so this compiler is natively supported. It gives no
-warnings with compiler options "-Wall -Wextra -pedantic -ansi", with gcc and g++
-version 4.7.1 on Linux, 32-bit and 64-bit.
-
-*) Clang
-
-Fully supported and warning-free.
-
-*) Mingw
-
-The Mingw compiler (a port of gcc for Windows) should be fully supported by
-LodePNG.
-
-*) Visual Studio and Visual C++ Express Edition
-
-LodePNG should be warning-free with warning level W4. Two warnings were disabled
-with pragmas though: warning 4244 about implicit conversions, and warning 4996
-where it wants to use a non-standard function fopen_s instead of the standard C
-fopen.
-
-Visual Studio may want "stdafx.h" files to be included in each source file and
-give an error "unexpected end of file while looking for precompiled header".
-This is not standard C++ and will not be added to the stock LodePNG. You can
-disable it for lodepng.cpp only by right clicking it, Properties, C/C++,
-Precompiled Headers, and set it to Not Using Precompiled Headers there.
-
-NOTE: Modern versions of VS should be fully supported, but old versions, e.g.
-VS6, are not guaranteed to work.
-
-*) Compilers on Macintosh
-
-LodePNG has been reported to work both with gcc and LLVM for Macintosh, both for
-C and C++.
-
-*) Other Compilers
-
-If you encounter problems on any compilers, feel free to let me know and I may
-try to fix it if the compiler is modern and standards compliant.
-
-
-10. examples
-------------
-
-This decoder example shows the most basic usage of LodePNG. More complex
-examples can be found on the LodePNG website.
-
-10.1. decoder C++ example
--------------------------
-
-#include "lodepng.h"
-#include <iostream>
-
-int main(int argc, char *argv[]) {
- const char* filename = argc > 1 ? argv[1] : "test.png";
-
- //load and decode
- std::vector<unsigned char> image;
- unsigned width, height;
- unsigned error = lodepng::decode(image, width, height, filename);
-
- //if there's an error, display it
- if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
-
- //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
-}
-
-10.2. decoder C example
------------------------
-
-#include "lodepng.h"
-
-int main(int argc, char *argv[]) {
- unsigned error;
- unsigned char* image;
- size_t width, height;
- const char* filename = argc > 1 ? argv[1] : "test.png";
-
- error = lodepng_decode32_file(&image, &width, &height, filename);
-
- if(error) printf("decoder error %u: %s\n", error, lodepng_error_text(error));
-
- / * use image here * /
-
- free(image);
- return 0;
-}
-
-11. state settings reference
-----------------------------
-
-A quick reference of some settings to set on the LodePNGState
-
-For decoding:
-
-state.decoder.zlibsettings.ignore_adler32: ignore ADLER32 checksums
-state.decoder.zlibsettings.custom_...: use custom inflate function
-state.decoder.ignore_crc: ignore CRC checksums
-state.decoder.ignore_critical: ignore unknown critical chunks
-state.decoder.ignore_end: ignore missing IEND chunk. May fail if this corruption causes other errors
-state.decoder.color_convert: convert internal PNG color to chosen one
-state.decoder.read_text_chunks: whether to read in text metadata chunks
-state.decoder.remember_unknown_chunks: whether to read in unknown chunks
-state.info_raw.colortype: desired color type for decoded image
-state.info_raw.bitdepth: desired bit depth for decoded image
-state.info_raw....: more color settings, see struct LodePNGColorMode
-state.info_png....: no settings for decoder but ouput, see struct LodePNGInfo
-
-For encoding:
-
-state.encoder.zlibsettings.btype: disable compression by setting it to 0
-state.encoder.zlibsettings.use_lz77: use LZ77 in compression
-state.encoder.zlibsettings.windowsize: tweak LZ77 windowsize
-state.encoder.zlibsettings.minmatch: tweak min LZ77 length to match
-state.encoder.zlibsettings.nicematch: tweak LZ77 match where to stop searching
-state.encoder.zlibsettings.lazymatching: try one more LZ77 matching
-state.encoder.zlibsettings.custom_...: use custom deflate function
-state.encoder.auto_convert: choose optimal PNG color type, if 0 uses info_png
-state.encoder.filter_palette_zero: PNG filter strategy for palette
-state.encoder.filter_strategy: PNG filter strategy to encode with
-state.encoder.force_palette: add palette even if not encoding to one
-state.encoder.add_id: add LodePNG identifier and version as a text chunk
-state.encoder.text_compression: use compressed text chunks for metadata
-state.info_raw.colortype: color type of raw input image you provide
-state.info_raw.bitdepth: bit depth of raw input image you provide
-state.info_raw: more color settings, see struct LodePNGColorMode
-state.info_png.color.colortype: desired color type if auto_convert is false
-state.info_png.color.bitdepth: desired bit depth if auto_convert is false
-state.info_png.color....: more color settings, see struct LodePNGColorMode
-state.info_png....: more PNG related settings, see struct LodePNGInfo
-
-
-12. changes
------------
-
-The version number of LodePNG is the date of the change given in the format
-yyyymmdd.
-
-Some changes aren't backwards compatible. Those are indicated with a (!)
-symbol.
-
-Not all changes are listed here, the commit history in github lists more:
-https://github.com/lvandeve/lodepng
-
-*) 17 okt 2020: prevent decoding too large text/icc chunks by default.
-*) 06 mar 2020: simplified some of the dynamic memory allocations.
-*) 12 jan 2020: (!) added 'end' argument to lodepng_chunk_next to allow correct
- overflow checks.
-*) 14 aug 2019: around 25% faster decoding thanks to huffman lookup tables.
-*) 15 jun 2019: (!) auto_choose_color API changed (for bugfix: don't use palette
- if gray ICC profile) and non-ICC LodePNGColorProfile renamed to
- LodePNGColorStats.
-*) 30 dec 2018: code style changes only: removed newlines before opening braces.
-*) 10 sep 2018: added way to inspect metadata chunks without full decoding.
-*) 19 aug 2018: (!) fixed color mode bKGD is encoded with and made it use
- palette index in case of palette.
-*) 10 aug 2018: (!) added support for gAMA, cHRM, sRGB and iCCP chunks. This
- change is backwards compatible unless you relied on unknown_chunks for those.
-*) 11 jun 2018: less restrictive check for pixel size integer overflow
-*) 14 jan 2018: allow optionally ignoring a few more recoverable errors
-*) 17 sep 2017: fix memory leak for some encoder input error cases
-*) 27 nov 2016: grey+alpha auto color model detection bugfix
-*) 18 apr 2016: Changed qsort to custom stable sort (for platforms w/o qsort).
-*) 09 apr 2016: Fixed colorkey usage detection, and better file loading (within
- the limits of pure C90).
-*) 08 dec 2015: Made load_file function return error if file can't be opened.
-*) 24 okt 2015: Bugfix with decoding to palette output.
-*) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding.
-*) 24 aug 2014: Moved to github
-*) 23 aug 2014: Reduced needless memory usage of decoder.
-*) 28 jun 2014: Removed fix_png setting, always support palette OOB for
- simplicity. Made ColorProfile public.
-*) 09 jun 2014: Faster encoder by fixing hash bug and more zeros optimization.
-*) 22 dec 2013: Power of two windowsize required for optimization.
-*) 15 apr 2013: Fixed bug with LAC_ALPHA and color key.
-*) 25 mar 2013: Added an optional feature to ignore some PNG errors (fix_png).
-*) 11 mar 2013: (!) Bugfix with custom free. Changed from "my" to "lodepng_"
- prefix for the custom allocators and made it possible with a new #define to
- use custom ones in your project without needing to change lodepng's code.
-*) 28 jan 2013: Bugfix with color key.
-*) 27 okt 2012: Tweaks in text chunk keyword length error handling.
-*) 8 okt 2012: (!) Added new filter strategy (entropy) and new auto color mode.
- (no palette). Better deflate tree encoding. New compression tweak settings.
- Faster color conversions while decoding. Some internal cleanups.
-*) 23 sep 2012: Reduced warnings in Visual Studio a little bit.
-*) 1 sep 2012: (!) Removed #define's for giving custom (de)compression functions
- and made it work with function pointers instead.
-*) 23 jun 2012: Added more filter strategies. Made it easier to use custom alloc
- and free functions and toggle #defines from compiler flags. Small fixes.
-*) 6 may 2012: (!) Made plugging in custom zlib/deflate functions more flexible.
-*) 22 apr 2012: (!) Made interface more consistent, renaming a lot. Removed
- redundant C++ codec classes. Reduced amount of structs. Everything changed,
- but it is cleaner now imho and functionality remains the same. Also fixed
- several bugs and shrunk the implementation code. Made new samples.
-*) 6 nov 2011: (!) By default, the encoder now automatically chooses the best
- PNG color model and bit depth, based on the amount and type of colors of the
- raw image. For this, autoLeaveOutAlphaChannel replaced by auto_choose_color.
-*) 9 okt 2011: simpler hash chain implementation for the encoder.
-*) 8 sep 2011: lz77 encoder lazy matching instead of greedy matching.
-*) 23 aug 2011: tweaked the zlib compression parameters after benchmarking.
- A bug with the PNG filtertype heuristic was fixed, so that it chooses much
- better ones (it's quite significant). A setting to do an experimental, slow,
- brute force search for PNG filter types is added.
-*) 17 aug 2011: (!) changed some C zlib related function names.
-*) 16 aug 2011: made the code less wide (max 120 characters per line).
-*) 17 apr 2011: code cleanup. Bugfixes. Convert low to 16-bit per sample colors.
-*) 21 feb 2011: fixed compiling for C90. Fixed compiling with sections disabled.
-*) 11 dec 2010: encoding is made faster, based on suggestion by Peter Eastman
- to optimize long sequences of zeros.
-*) 13 nov 2010: added LodePNG_InfoColor_hasPaletteAlpha and
- LodePNG_InfoColor_canHaveAlpha functions for convenience.
-*) 7 nov 2010: added LodePNG_error_text function to get error code description.
-*) 30 okt 2010: made decoding slightly faster
-*) 26 okt 2010: (!) changed some C function and struct names (more consistent).
- Reorganized the documentation and the declaration order in the header.
-*) 08 aug 2010: only changed some comments and external samples.
-*) 05 jul 2010: fixed bug thanks to warnings in the new gcc version.
-*) 14 mar 2010: fixed bug where too much memory was allocated for char buffers.
-*) 02 sep 2008: fixed bug where it could create empty tree that linux apps could
- read by ignoring the problem but windows apps couldn't.
-*) 06 jun 2008: added more error checks for out of memory cases.
-*) 26 apr 2008: added a few more checks here and there to ensure more safety.
-*) 06 mar 2008: crash with encoding of strings fixed
-*) 02 feb 2008: support for international text chunks added (iTXt)
-*) 23 jan 2008: small cleanups, and #defines to divide code in sections
-*) 20 jan 2008: support for unknown chunks allowing using LodePNG for an editor.
-*) 18 jan 2008: support for tIME and pHYs chunks added to encoder and decoder.
-*) 17 jan 2008: ability to encode and decode compressed zTXt chunks added
- Also various fixes, such as in the deflate and the padding bits code.
-*) 13 jan 2008: Added ability to encode Adam7-interlaced images. Improved
- filtering code of encoder.
-*) 07 jan 2008: (!) changed LodePNG to use ISO C90 instead of C++. A
- C++ wrapper around this provides an interface almost identical to before.
- Having LodePNG be pure ISO C90 makes it more portable. The C and C++ code
- are together in these files but it works both for C and C++ compilers.
-*) 29 dec 2007: (!) changed most integer types to unsigned int + other tweaks
-*) 30 aug 2007: bug fixed which makes this Borland C++ compatible
-*) 09 aug 2007: some VS2005 warnings removed again
-*) 21 jul 2007: deflate code placed in new namespace separate from zlib code
-*) 08 jun 2007: fixed bug with 2- and 4-bit color, and small interlaced images
-*) 04 jun 2007: improved support for Visual Studio 2005: crash with accessing
- invalid std::vector element [0] fixed, and level 3 and 4 warnings removed
-*) 02 jun 2007: made the encoder add a tag with version by default
-*) 27 may 2007: zlib and png code separated (but still in the same file),
- simple encoder/decoder functions added for more simple usage cases
-*) 19 may 2007: minor fixes, some code cleaning, new error added (error 69),
- moved some examples from here to lodepng_examples.cpp
-*) 12 may 2007: palette decoding bug fixed
-*) 24 apr 2007: changed the license from BSD to the zlib license
-*) 11 mar 2007: very simple addition: ability to encode bKGD chunks.
-*) 04 mar 2007: (!) tEXt chunk related fixes, and support for encoding
- palettized PNG images. Plus little interface change with palette and texts.
-*) 03 mar 2007: Made it encode dynamic Huffman shorter with repeat codes.
- Fixed a bug where the end code of a block had length 0 in the Huffman tree.
-*) 26 feb 2007: Huffman compression with dynamic trees (BTYPE 2) now implemented
- and supported by the encoder, resulting in smaller PNGs at the output.
-*) 27 jan 2007: Made the Adler-32 test faster so that a timewaste is gone.
-*) 24 jan 2007: gave encoder an error interface. Added color conversion from any
- greyscale type to 8-bit greyscale with or without alpha.
-*) 21 jan 2007: (!) Totally changed the interface. It allows more color types
- to convert to and is more uniform. See the manual for how it works now.
-*) 07 jan 2007: Some cleanup & fixes, and a few changes over the last days:
- encode/decode custom tEXt chunks, separate classes for zlib & deflate, and
- at last made the decoder give errors for incorrect Adler32 or Crc.
-*) 01 jan 2007: Fixed bug with encoding PNGs with less than 8 bits per channel.
-*) 29 dec 2006: Added support for encoding images without alpha channel, and
- cleaned out code as well as making certain parts faster.
-*) 28 dec 2006: Added "Settings" to the encoder.
-*) 26 dec 2006: The encoder now does LZ77 encoding and produces much smaller files now.
- Removed some code duplication in the decoder. Fixed little bug in an example.
-*) 09 dec 2006: (!) Placed output parameters of public functions as first parameter.
- Fixed a bug of the decoder with 16-bit per color.
-*) 15 okt 2006: Changed documentation structure
-*) 09 okt 2006: Encoder class added. It encodes a valid PNG image from the
- given image buffer, however for now it's not compressed.
-*) 08 sep 2006: (!) Changed to interface with a Decoder class
-*) 30 jul 2006: (!) LodePNG_InfoPng , width and height are now retrieved in different
- way. Renamed decodePNG to decodePNGGeneric.
-*) 29 jul 2006: (!) Changed the interface: image info is now returned as a
- struct of type LodePNG::LodePNG_Info, instead of a vector, which was a bit clumsy.
-*) 28 jul 2006: Cleaned the code and added new error checks.
- Corrected terminology "deflate" into "inflate".
-*) 23 jun 2006: Added SDL example in the documentation in the header, this
- example allows easy debugging by displaying the PNG and its transparency.
-*) 22 jun 2006: (!) Changed way to obtain error value. Added
- loadFile function for convenience. Made decodePNG32 faster.
-*) 21 jun 2006: (!) Changed type of info vector to unsigned.
- Changed position of palette in info vector. Fixed an important bug that
- happened on PNGs with an uncompressed block.
-*) 16 jun 2006: Internally changed unsigned into unsigned where
- needed, and performed some optimizations.
-*) 07 jun 2006: (!) Renamed functions to decodePNG and placed them
- in LodePNG namespace. Changed the order of the parameters. Rewrote the
- documentation in the header. Renamed files to lodepng.cpp and lodepng.h
-*) 22 apr 2006: Optimized and improved some code
-*) 07 sep 2005: (!) Changed to std::vector interface
-*) 12 aug 2005: Initial release (C++, decoder only)
-
-
-13. contact information
------------------------
-
-Feel free to contact me with suggestions, problems, comments, ... concerning
-LodePNG. If you encounter a PNG image that doesn't work properly with this
-decoder, feel free to send it and I'll use it to find and fix the problem.
-
-My email address is (puzzle the account and domain together with an @ symbol):
-Domain: gmail dot com.
-Account: lode dot vandevenne.
-
-
-Copyright (c) 2005-2020 Lode Vandevenne
-*/
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