Fix issues of restriction of chat message charset (#391)v1.12.0-rc1

2 files changed, 89 insertions, 0 deletions

diff --git a/NorthstarDLL/util/utils.cpp b/NorthstarDLL/util/utils.cpp
new file mode 100644
index 00000000..10c5b26d
--- /dev/null
+++ b/NorthstarDLL/util/utils.cpp
@@ -0,0 +1,83 @@
+#include "pch.h"
+#include <ctype.h>
+#include "utils.h"
+
+bool skip_valid_ansi_csi_sgr(char*& str)
+{
+	if (*str++ != '\x1B')
+		return false;
+	if (*str++ != '[') // CSI
+		return false;
+	for (char* c = str; *c; c++)
+	{
+		if (*c >= '0' && *c <= '9')
+			continue;
+		if (*c == ';' || *c == ':')
+			continue;
+		if (*c == 'm') // SGR
+			break;
+		return false;
+	}
+	return true;
+}
+
+void NS::Utils::RemoveAsciiControlSequences(char* str, bool allow_color_codes)
+{
+	for (char *pc = str, c = *pc; c = *pc; pc++)
+	{
+		// skip UTF-8 characters
+		int bytesToSkip = 0;
+		if ((c & 0xE0) == 0xC0)
+			bytesToSkip = 1; // skip 2-byte UTF-8 sequence
+		if ((c & 0xF0) == 0xE0)
+			bytesToSkip = 2; // skip 3-byte UTF-8 sequence
+		if ((c & 0xF8) == 0xF0)
+			bytesToSkip = 3; // skip 4-byte UTF-8 sequence
+		if ((c & 0xFC) == 0xF8)
+			bytesToSkip = 4; // skip 5-byte UTF-8 sequence
+		if ((c & 0xFE) == 0xFC)
+			bytesToSkip = 5; // skip 6-byte UTF-8 sequence
+
+		bool invalid = false;
+		char* orgpc = pc;
+		for (int i = 0; i < bytesToSkip; i++)
+		{
+			char next = pc[1];
+
+			// valid UTF-8 part
+			if ((next & 0xC0) == 0x80)
+			{
+				pc++;
+				continue;
+			}
+
+			// invalid UTF-8 part or encountered \0
+			invalid = true;
+			break;
+		}
+		if (invalid)
+		{
+			// erase the whole "UTF-8" sequence
+			for (char* x = orgpc; x <= pc; x++)
+				if (*x != '\0')
+					*x = ' ';
+				else
+					break;
+		}
+		if (bytesToSkip > 0)
+			continue; // this byte was already handled as UTF-8
+
+		// an invalid control character or an UTF-8 part outside of UTF-8 sequence
+		if ((iscntrl(c) && c != '\n' && c != '\r' && c != '\x1B') || (c & 0x80) != 0)
+		{
+			*pc = ' ';
+			continue;
+		}
+
+		if (c == '\x1B') // separate handling for this escape sequence...
+			if (allow_color_codes && skip_valid_ansi_csi_sgr(pc)) // ...which we allow for color codes...
+				pc--;
+			else // ...but remove it otherwise
+				*pc = ' ';
+	}
+}
diff --git a/NorthstarDLL/util/utils.h b/NorthstarDLL/util/utils.h
new file mode 100644
index 00000000..97b92f18
--- /dev/null
+++ b/NorthstarDLL/util/utils.h
@@ -0,0 +1,6 @@
+#pragma once
+
+namespace NS::Utils
+{
+	void RemoveAsciiControlSequences(char* str, bool allow_color_codes);
+}