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kc3-lang/ftgl/src/FTUnicode.h
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- src/FTUnicode.h
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/* * FTGL - OpenGL font library * * Copyright (c) 2008 Daniel Remenak <dtremenak@users.sourceforge.net> * * Portions derived from ConvertUTF.c Copyright (C) 2001-2004 Unicode, Inc * Unicode, Inc. hereby grants the right to freely use the information * supplied in this file in the creation of products supporting the * Unicode Standard, and to make copies of this file in any form * for internal or external distribution as long as this notice * remains attached. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #ifndef __FTUnicode__ #define __FTUnicode__ /** * Provides a way to easily walk multibyte unicode strings in the various * Unicode encodings (UTF-8, UTF-16, UTF-32, UCS-2, and UCS-4). Encodings * with elements larger than one byte must already be in the correct endian * order for the current architecture. */ template <typename T> class FTUnicodeStringItr { public: /** * Constructor. Also reads the first character and stores it. * * @param string The buffer to iterate. No copy is made. */ FTUnicodeStringItr(const T* string) : curPos(string), nextPos(string) { (*this)++; }; /** * Pre-increment operator. Reads the next unicode character and sets * the state appropriately. * Note - not protected against overruns. */ FTUnicodeStringItr& operator++() { curPos = nextPos; // unicode handling switch (sizeof(T)) { case 1: // UTF-8 // get this character readUTF8(); break; case 2: // UTF-16 readUTF16(); break; case 4: // UTF-32 // fall through default: // error condition really, but give it a shot anyway curChar = *nextPos++; } return *this; } /** * Post-increment operator. Reads the next character and sets * the state appropriately. * Note - not protected against overruns. */ FTUnicodeStringItr operator++(int) { FTUnicodeStringItr temp = *this; ++*this; return temp; } /** * Equality operator. Two FTUnicodeStringItrs are considered equal * if they have the same current buffer and buffer position. */ bool operator==(const FTUnicodeStringItr& right) const { if (curPos == right.getBufferFromHere()) return true; return false; } /** * Dereference operator. * * @return The unicode codepoint of the character currently pointed * to by the FTUnicodeStringItr. */ unsigned int operator*() const { return curChar; } /** * Buffer-fetching getter. You can use this to retreive the buffer * starting at the currently-iterated character for functions which * require a Unicode string as input. */ const T* getBufferFromHere() const { return curPos; } private: /** * Helper function for reading a single UTF8 character from the string. * Updates internal state appropriately. */ void readUTF8(); /** * Helper function for reading a single UTF16 character from the string. * Updates internal state appropriately. */ void readUTF16(); /** * The buffer position of the first element in the current character. */ const T* curPos; /** * The character stored at the current buffer position (prefetched on * increment, so there's no penalty for dereferencing more than once). */ unsigned int curChar; /** * The buffer position of the first element in the next character. */ const T* nextPos; // unicode magic numbers static const unsigned char utf8bytes[256]; static const unsigned long offsetsFromUTF8[6]; static const unsigned long highSurrogateStart; static const unsigned long highSurrogateEnd; static const unsigned long lowSurrogateStart; static const unsigned long lowSurrogateEnd; static const unsigned long highSurrogateShift; static const unsigned long lowSurrogateBase; }; /* The first character in a UTF8 sequence indicates how many bytes * to read (among other things) */ template <typename T> const unsigned char FTUnicodeStringItr<T>::utf8bytes[256] = { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4,5,5,5,5,6,6,6,6 }; /* Magic values subtracted from a buffer value during UTF8 conversion. * This table contains as many values as there might be trailing bytes * in a UTF-8 sequence. */ template <typename T> const unsigned long FTUnicodeStringItr<T>::offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, 0x03C82080UL, 0xFA082080UL, 0x82082080UL }; // get a UTF8 character; leave the tracking pointer at the start of the // next character // not protected against invalid UTF8 template <typename T> inline void FTUnicodeStringItr<T>::readUTF8() { unsigned int ch = 0; unsigned int extraBytesToRead = utf8bytes[(unsigned char)(*nextPos)]; // falls through switch (extraBytesToRead) { case 6: ch += *nextPos++; ch <<= 6; /* remember, illegal UTF-8 */ case 5: ch += *nextPos++; ch <<= 6; /* remember, illegal UTF-8 */ case 4: ch += *nextPos++; ch <<= 6; case 3: ch += *nextPos++; ch <<= 6; case 2: ch += *nextPos++; ch <<= 6; case 1: ch += *nextPos++; } ch -= offsetsFromUTF8[extraBytesToRead-1]; curChar = ch; } // Magic numbers for UTF-16 conversions template <typename T> const unsigned long FTUnicodeStringItr<T>::highSurrogateStart = 0xD800; template <typename T> const unsigned long FTUnicodeStringItr<T>::highSurrogateEnd = 0xDBFF; template <typename T> const unsigned long FTUnicodeStringItr<T>::lowSurrogateStart = 0xDC00; template <typename T> const unsigned long FTUnicodeStringItr<T>::lowSurrogateEnd = 0xDFFF; template <typename T> const unsigned long FTUnicodeStringItr<T>::highSurrogateShift = 10; template <typename T> const unsigned long FTUnicodeStringItr<T>::lowSurrogateBase = 0x0010000UL; template <typename T> inline void FTUnicodeStringItr<T>::readUTF16() { unsigned int ch = *nextPos++; // if we have the first half of the surrogate pair if (ch >= highSurrogateStart && ch <= highSurrogateEnd) { unsigned int ch2 = *curPos; // complete the surrogate pair if (ch2 >= lowSurrogateStart && ch2 <= lowSurrogateEnd) { ch = ((ch - highSurrogateStart) << highSurrogateShift) + (ch2 - lowSurrogateStart) + lowSurrogateBase; ++nextPos; } } curChar = ch; } #endif