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Diffstat (limited to 'src/ftgl/FTUnicode.h')
| -rw-r--r-- | src/ftgl/FTUnicode.h | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/src/ftgl/FTUnicode.h b/src/ftgl/FTUnicode.h new file mode 100644 index 0000000..6c74100 --- /dev/null +++ b/src/ftgl/FTUnicode.h @@ -0,0 +1,237 @@ +/* + * 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 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 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 |