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Diffstat (limited to 'NorthstarDLL/include/rapidjson/allocators.h')
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diff --git a/NorthstarDLL/include/rapidjson/allocators.h b/NorthstarDLL/include/rapidjson/allocators.h new file mode 100644 index 00000000..98affe03 --- /dev/null +++ b/NorthstarDLL/include/rapidjson/allocators.h @@ -0,0 +1,271 @@ +// Tencent is pleased to support the open source community by making RapidJSON available. +// +// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. +// +// Licensed under the MIT License (the "License"); you may not use this file except +// in compliance with the License. You may obtain a copy of the License at +// +// http://opensource.org/licenses/MIT +// +// Unless required by applicable law or agreed to in writing, software distributed +// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR +// CONDITIONS OF ANY KIND, either express or implied. See the License for the +// specific language governing permissions and limitations under the License. + +#ifndef RAPIDJSON_ALLOCATORS_H_ +#define RAPIDJSON_ALLOCATORS_H_ + +#include "rapidjson.h" + +RAPIDJSON_NAMESPACE_BEGIN + +/////////////////////////////////////////////////////////////////////////////// +// Allocator + +/*! \class rapidjson::Allocator + \brief Concept for allocating, resizing and freeing memory block. + + Note that Malloc() and Realloc() are non-static but Free() is static. + + So if an allocator need to support Free(), it needs to put its pointer in + the header of memory block. + +\code +concept Allocator { + static const bool kNeedFree; //!< Whether this allocator needs to call Free(). + + // Allocate a memory block. + // \param size of the memory block in bytes. + // \returns pointer to the memory block. + void* Malloc(size_t size); + + // Resize a memory block. + // \param originalPtr The pointer to current memory block. Null pointer is permitted. + // \param originalSize The current size in bytes. (Design issue: since some allocator may not book-keep this, explicitly pass to it can save memory.) + // \param newSize the new size in bytes. + void* Realloc(void* originalPtr, size_t originalSize, size_t newSize); + + // Free a memory block. + // \param pointer to the memory block. Null pointer is permitted. + static void Free(void *ptr); +}; +\endcode +*/ + +/////////////////////////////////////////////////////////////////////////////// +// CrtAllocator + +//! C-runtime library allocator. +/*! This class is just wrapper for standard C library memory routines. + \note implements Allocator concept +*/ +class CrtAllocator { +public: + static const bool kNeedFree = true; + void* Malloc(size_t size) { + if (size) // behavior of malloc(0) is implementation defined. + return std::malloc(size); + else + return NULL; // standardize to returning NULL. + } + void* Realloc(void* originalPtr, size_t originalSize, size_t newSize) { + (void)originalSize; + if (newSize == 0) { + std::free(originalPtr); + return NULL; + } + return std::realloc(originalPtr, newSize); + } + static void Free(void *ptr) { std::free(ptr); } +}; + +/////////////////////////////////////////////////////////////////////////////// +// MemoryPoolAllocator + +//! Default memory allocator used by the parser and DOM. +/*! This allocator allocate memory blocks from pre-allocated memory chunks. + + It does not free memory blocks. And Realloc() only allocate new memory. + + The memory chunks are allocated by BaseAllocator, which is CrtAllocator by default. + + User may also supply a buffer as the first chunk. + + If the user-buffer is full then additional chunks are allocated by BaseAllocator. + + The user-buffer is not deallocated by this allocator. + + \tparam BaseAllocator the allocator type for allocating memory chunks. Default is CrtAllocator. + \note implements Allocator concept +*/ +template <typename BaseAllocator = CrtAllocator> +class MemoryPoolAllocator { +public: + static const bool kNeedFree = false; //!< Tell users that no need to call Free() with this allocator. (concept Allocator) + + //! Constructor with chunkSize. + /*! \param chunkSize The size of memory chunk. The default is kDefaultChunkSize. + \param baseAllocator The allocator for allocating memory chunks. + */ + MemoryPoolAllocator(size_t chunkSize = kDefaultChunkCapacity, BaseAllocator* baseAllocator = 0) : + chunkHead_(0), chunk_capacity_(chunkSize), userBuffer_(0), baseAllocator_(baseAllocator), ownBaseAllocator_(0) + { + } + + //! Constructor with user-supplied buffer. + /*! The user buffer will be used firstly. When it is full, memory pool allocates new chunk with chunk size. + + The user buffer will not be deallocated when this allocator is destructed. + + \param buffer User supplied buffer. + \param size Size of the buffer in bytes. It must at least larger than sizeof(ChunkHeader). + \param chunkSize The size of memory chunk. The default is kDefaultChunkSize. + \param baseAllocator The allocator for allocating memory chunks. + */ + MemoryPoolAllocator(void *buffer, size_t size, size_t chunkSize = kDefaultChunkCapacity, BaseAllocator* baseAllocator = 0) : + chunkHead_(0), chunk_capacity_(chunkSize), userBuffer_(buffer), baseAllocator_(baseAllocator), ownBaseAllocator_(0) + { + RAPIDJSON_ASSERT(buffer != 0); + RAPIDJSON_ASSERT(size > sizeof(ChunkHeader)); + chunkHead_ = reinterpret_cast<ChunkHeader*>(buffer); + chunkHead_->capacity = size - sizeof(ChunkHeader); + chunkHead_->size = 0; + chunkHead_->next = 0; + } + + //! Destructor. + /*! This deallocates all memory chunks, excluding the user-supplied buffer. + */ + ~MemoryPoolAllocator() { + Clear(); + RAPIDJSON_DELETE(ownBaseAllocator_); + } + + //! Deallocates all memory chunks, excluding the user-supplied buffer. + void Clear() { + while (chunkHead_ && chunkHead_ != userBuffer_) { + ChunkHeader* next = chunkHead_->next; + baseAllocator_->Free(chunkHead_); + chunkHead_ = next; + } + if (chunkHead_ && chunkHead_ == userBuffer_) + chunkHead_->size = 0; // Clear user buffer + } + + //! Computes the total capacity of allocated memory chunks. + /*! \return total capacity in bytes. + */ + size_t Capacity() const { + size_t capacity = 0; + for (ChunkHeader* c = chunkHead_; c != 0; c = c->next) + capacity += c->capacity; + return capacity; + } + + //! Computes the memory blocks allocated. + /*! \return total used bytes. + */ + size_t Size() const { + size_t size = 0; + for (ChunkHeader* c = chunkHead_; c != 0; c = c->next) + size += c->size; + return size; + } + + //! Allocates a memory block. (concept Allocator) + void* Malloc(size_t size) { + if (!size) + return NULL; + + size = RAPIDJSON_ALIGN(size); + if (chunkHead_ == 0 || chunkHead_->size + size > chunkHead_->capacity) + if (!AddChunk(chunk_capacity_ > size ? chunk_capacity_ : size)) + return NULL; + + void *buffer = reinterpret_cast<char *>(chunkHead_) + RAPIDJSON_ALIGN(sizeof(ChunkHeader)) + chunkHead_->size; + chunkHead_->size += size; + return buffer; + } + + //! Resizes a memory block (concept Allocator) + void* Realloc(void* originalPtr, size_t originalSize, size_t newSize) { + if (originalPtr == 0) + return Malloc(newSize); + + if (newSize == 0) + return NULL; + + originalSize = RAPIDJSON_ALIGN(originalSize); + newSize = RAPIDJSON_ALIGN(newSize); + + // Do not shrink if new size is smaller than original + if (originalSize >= newSize) + return originalPtr; + + // Simply expand it if it is the last allocation and there is sufficient space + if (originalPtr == reinterpret_cast<char *>(chunkHead_) + RAPIDJSON_ALIGN(sizeof(ChunkHeader)) + chunkHead_->size - originalSize) { + size_t increment = static_cast<size_t>(newSize - originalSize); + if (chunkHead_->size + increment <= chunkHead_->capacity) { + chunkHead_->size += increment; + return originalPtr; + } + } + + // Realloc process: allocate and copy memory, do not free original buffer. + if (void* newBuffer = Malloc(newSize)) { + if (originalSize) + std::memcpy(newBuffer, originalPtr, originalSize); + return newBuffer; + } + else + return NULL; + } + + //! Frees a memory block (concept Allocator) + static void Free(void *ptr) { (void)ptr; } // Do nothing + +private: + //! Copy constructor is not permitted. + MemoryPoolAllocator(const MemoryPoolAllocator& rhs) /* = delete */; + //! Copy assignment operator is not permitted. + MemoryPoolAllocator& operator=(const MemoryPoolAllocator& rhs) /* = delete */; + + //! Creates a new chunk. + /*! \param capacity Capacity of the chunk in bytes. + \return true if success. + */ + bool AddChunk(size_t capacity) { + if (!baseAllocator_) + ownBaseAllocator_ = baseAllocator_ = RAPIDJSON_NEW(BaseAllocator()); + if (ChunkHeader* chunk = reinterpret_cast<ChunkHeader*>(baseAllocator_->Malloc(RAPIDJSON_ALIGN(sizeof(ChunkHeader)) + capacity))) { + chunk->capacity = capacity; + chunk->size = 0; + chunk->next = chunkHead_; + chunkHead_ = chunk; + return true; + } + else + return false; + } + + static const int kDefaultChunkCapacity = 64 * 1024; //!< Default chunk capacity. + + //! Chunk header for perpending to each chunk. + /*! Chunks are stored as a singly linked list. + */ + struct ChunkHeader { + size_t capacity; //!< Capacity of the chunk in bytes (excluding the header itself). + size_t size; //!< Current size of allocated memory in bytes. + ChunkHeader *next; //!< Next chunk in the linked list. + }; + + ChunkHeader *chunkHead_; //!< Head of the chunk linked-list. Only the head chunk serves allocation. + size_t chunk_capacity_; //!< The minimum capacity of chunk when they are allocated. + void *userBuffer_; //!< User supplied buffer. + BaseAllocator* baseAllocator_; //!< base allocator for allocating memory chunks. + BaseAllocator* ownBaseAllocator_; //!< base allocator created by this object. +}; + +RAPIDJSON_NAMESPACE_END + +#endif // RAPIDJSON_ENCODINGS_H_ |