442 lines
12 KiB
C
442 lines
12 KiB
C
/*
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This file is part of Warzone 2100.
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Copyright (C) 2007 Giel van Schijndel
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Copyright (C) 2007 Warzone Resurrection Project
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Warzone 2100 is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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Warzone 2100 is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Warzone 2100; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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$Revision$
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$Id$
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$HeadURL$
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*/
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/** \file
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* Functions to convert between different Unicode Transformation Formats (UTF for short)
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*/
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#include "utf.h"
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#include <assert.h>
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#if defined(LIB_COMPILE)
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# define ASSERT(expr, ...) (assert(expr))
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# define debug(part, ...) ((void)0)
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#else
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# include "debug.h"
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#endif
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// Assert that non-starting octets are of the form 10xxxxxx
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#define ASSERT_NON_START_OCTET(octet) \
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assert((octet & 0xC0) == 0x80 && "invalid non-start UTF-8 octet")
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// Assert that starting octets are either of the form 0xxxxxxx (ASCII) or 11xxxxxx
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#define ASSERT_START_OCTECT(octet) \
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assert((octet & 0x80) == 0x00 || (octet & 0xC0) == 0xC0 || !"invalid starting UTF-8 octet")
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// Assert that hexadect (16bit sequence) 1 of UTF-16 surrogate pair sequences are of the form 110110XXXXXXXXXX
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#define ASSERT_START_HEXADECT(hexadect) \
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assert(((hexadect) & 0xD800) == 0xD800 && "invalid first UTF-16 hexadect")
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// Assert that hexadect (16bit sequence) 2 of UTF-16 surrogate pair sequences are of the form 110111XXXXXXXXXX
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#define ASSERT_FINAL_HEXADECT(hexadect) \
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assert(((hexadect) & 0xDC00) == 0xDC00 && "invalid first UTF-16 hexadect")
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utf_32_char UTF8DecodeChar(const char *utf8_char, const char **next_char)
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{
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utf_32_char decoded;
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*next_char = utf8_char;
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ASSERT_START_OCTECT(*utf8_char);
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// first octect: 0xxxxxxx: 7 bit (ASCII)
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if ((*utf8_char & 0x80) == 0x00)
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{
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// 1 byte long encoding
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decoded = *((*next_char)++);
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}
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// first octect: 110xxxxx: 11 bit
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else if ((*utf8_char & 0xe0) == 0xc0)
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{
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// 2 byte long encoding
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ASSERT_NON_START_OCTET(utf8_char[1]);
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decoded = (*((*next_char)++) & 0x1f) << 6;
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decoded |= (*((*next_char)++) & 0x3f) << 0;
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}
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// first octect: 1110xxxx: 16 bit
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else if ((*utf8_char & 0xf0) == 0xe0)
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{
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// 3 byte long encoding
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ASSERT_NON_START_OCTET(utf8_char[1]);
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ASSERT_NON_START_OCTET(utf8_char[2]);
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decoded = (*((*next_char)++) & 0x0f) << 12;
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decoded |= (*((*next_char)++) & 0x3f) << 6;
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decoded |= (*((*next_char)++) & 0x3f) << 0;
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}
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// first octect: 11110xxx: 21 bit
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else if ((*utf8_char & 0xf8) == 0xf0)
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{
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// 4 byte long encoding
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ASSERT_NON_START_OCTET(utf8_char[1]);
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ASSERT_NON_START_OCTET(utf8_char[2]);
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ASSERT_NON_START_OCTET(utf8_char[3]);
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decoded = (*((*next_char)++) & 0x07) << 18;
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decoded |= (*((*next_char)++) & 0x3f) << 12;
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decoded |= (*((*next_char)++) & 0x3f) << 6;
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decoded |= (*((*next_char)++) & 0x3f) << 0;
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}
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else
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{
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// apparently this character uses more than 21 bit
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// this decoder is not developed to cope with those
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// characters so error out
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ASSERT(!"out-of-range UTF-8 character", "this UTF-8 character is too large (> 21bits) for this UTF-8 decoder and too large to be a valid Unicode codepoint");
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}
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return decoded;
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}
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size_t UTF8CharacterCount(const char *utf8_string)
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{
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size_t length = 0;
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while (*utf8_string != '\0')
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{
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UTF8DecodeChar(utf8_string, &utf8_string);
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++length;
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}
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return length;
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}
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size_t UTF16CharacterCount(const uint16_t *utf16)
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{
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size_t length = 0;
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while (*utf16)
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{
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UTF16DecodeChar(utf16, &utf16);
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++length;
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}
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return length;
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}
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static size_t unicode_utf8_char_length(const utf_32_char unicode_char)
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{
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// an ASCII character, which uses 7 bit at most, which is one byte in UTF-8
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if (unicode_char < 0x00000080)
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return 1; // stores 7 bits
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else if (unicode_char < 0x00000800)
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return 2; // stores 11 bits
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else if (unicode_char < 0x00010000)
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return 3; // stores 16 bits
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/* This encoder can deal with < 0x00200000, but Unicode only ranges
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* from 0x0 to 0x10FFFF. Thus we don't accept anything else.
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*/
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else if (unicode_char < 0x00110000)
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return 4; // stores 21 bits
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/* Apparently this character lies outside the 0x0 - 0x10FFFF
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* Unicode range, so don't accept it.
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*/
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ASSERT(!"out-of-range Unicode codepoint", "This Unicode codepoint is too large (%u > 0x10FFFF) to be a valid Unicode codepoint", (unsigned int)unicode_char);
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// Dummy value to prevent warnings about missing return from function
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return 0;
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}
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char *UTF8CharacterAtOffset(const char *utf8_string, size_t index)
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{
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while (*utf8_string != '\0'
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&& index != 0)
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{
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// Move to the next character
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UTF8DecodeChar(utf8_string, &utf8_string);
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--index;
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}
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if (*utf8_string == '\0')
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return NULL;
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return (char*)utf8_string;
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}
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/** Encodes a single Unicode character to a UTF-8 encoded string.
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*
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* \param unicode_char A UTF-32 encoded Unicode codepoint that will be encoded
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* into UTF-8. This should be a valid Unicode codepoint
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* (i.e. ranging from 0x0 to 0x10FFFF inclusive).
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* \param out_char Points to the position in a buffer where the UTF-8
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* encoded character can be stored.
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*
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* \return A pointer pointing to the first byte <em>after</em> the encoded
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* UTF-8 sequence. This can be used as the \c out_char parameter for a
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* next invocation of encode_utf8_char().
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*/
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static char *encode_utf8_char(const utf_32_char unicode_char, char *out_char)
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{
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char *next_char = out_char;
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// 7 bits
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if (unicode_char < 0x00000080)
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{
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*(next_char++) = unicode_char;
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}
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// 11 bits
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else if (unicode_char < 0x00000800)
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{
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// 0xc0 provides the counting bits: 110
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// then append the 5 most significant bits
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*(next_char++) = 0xc0 | (unicode_char >> 6);
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// Put the next 6 bits in a byte of their own
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*(next_char++) = 0x80 | (unicode_char & 0x3f);
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}
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// 16 bits
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else if (unicode_char < 0x00010000)
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{
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// 0xe0 provides the counting bits: 1110
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// then append the 4 most significant bits
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*(next_char++) = 0xe0 | (unicode_char >> 12);
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// Put the next 12 bits in two bytes of their own
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*(next_char++) = 0x80 | ((unicode_char >> 6) & 0x3f);
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*(next_char++) = 0x80 | (unicode_char & 0x3f);
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}
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// 21 bits
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/* This encoder can deal with < 0x00200000, but Unicode only ranges
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* from 0x0 to 0x10FFFF. Thus we don't accept anything else.
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*/
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else if (unicode_char < 0x00110000)
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{
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// 0xf0 provides the counting bits: 11110
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// then append the 3 most significant bits
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*(next_char++) = 0xf0 | (unicode_char >> 18);
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// Put the next 18 bits in three bytes of their own
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*(next_char++) = 0x80 | ((unicode_char >> 12) & 0x3f);
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*(next_char++) = 0x80 | ((unicode_char >> 6) & 0x3f);
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*(next_char++) = 0x80 | (unicode_char & 0x3f);
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}
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else
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{
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/* Apparently this character lies outside the 0x0 - 0x10FFFF
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* Unicode range, so don't accept it.
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*/
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ASSERT(!"out-of-range Unicode codepoint", "This Unicode codepoint is too large (%u > 0x10FFFF) to be a valid Unicode codepoint", (unsigned int)unicode_char);
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}
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return next_char;
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}
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utf_32_char UTF16DecodeChar(const utf_16_char *utf16_char, const utf_16_char **next_char)
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{
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utf_32_char decoded;
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*next_char = utf16_char;
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// Are we dealing with a surrogate pair
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if (*utf16_char >= 0xD800
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&& *utf16_char <= 0xDFFF)
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{
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ASSERT_START_HEXADECT(utf16_char[0]);
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ASSERT_FINAL_HEXADECT(utf16_char[1]);
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decoded = (*((*next_char)++) & 0x3ff) << 10;
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decoded |= *((*next_char)++) & 0x3ff;
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decoded += 0x10000;
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}
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// Not a surrogate pair, so it's a valid Unicode codepoint right away
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else
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{
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decoded = *((*next_char)++);
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}
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return decoded;
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}
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/** Encodes a single Unicode character to a UTF-16 encoded string.
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*
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* \param unicode_char A UTF-32 encoded Unicode codepoint that will be encoded
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* into UTF-16. This should be a valid Unicode codepoint
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* (i.e. ranging from 0x0 to 0x10FFFF inclusive).
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* \param out_char Points to the position in a buffer where the UTF-16
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* encoded character can be stored.
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*
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* \return A pointer pointing to the first byte <em>after</em> the encoded
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* UTF-16 sequence. This can be used as the \c out_char parameter for a
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* next invocation of encode_utf16_char().
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*/
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static utf_16_char *encode_utf16_char(const utf_32_char unicode_char, utf_16_char *out_char)
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{
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utf_16_char *next_char = out_char;
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// 16 bits
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if (unicode_char < 0x10000)
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{
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*(next_char++) = unicode_char;
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}
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else if (unicode_char < 0x110000)
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{
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const utf_16_char v = unicode_char - 0x10000;
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*(next_char++) = 0xD800 | (v >> 10);
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*(next_char++) = 0xDC00 | (v & 0x3ff);
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ASSERT_START_HEXADECT(out_char[0]);
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ASSERT_FINAL_HEXADECT(out_char[1]);
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}
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else
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{
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/* Apparently this character lies outside the 0x0 - 0x10FFFF
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* Unicode range, and UTF-16 cannot cope with that, so error
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* out.
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*/
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ASSERT(!"out-of-range Unicode codepoint", "This Unicode codepoint is too large (%u > 0x10FFFF) to be a valid Unicode codepoint", (unsigned int)unicode_char);
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}
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return next_char;
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}
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static size_t utf16_utf8_buffer_length(const utf_16_char* unicode_string)
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{
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const utf_16_char* curChar = unicode_string;
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// Determine length of string (in octets) when encoded in UTF-8
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size_t length = 0;
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while (*curChar)
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{
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length += unicode_utf8_char_length(UTF16DecodeChar(curChar, &curChar));
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}
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return length;
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}
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char *UTF16toUTF8(const utf_16_char *unicode_string, size_t *nbytes)
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{
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const utf_16_char* curChar;
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const size_t utf8_length = utf16_utf8_buffer_length(unicode_string);
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// Allocate memory to hold the UTF-8 encoded string (plus a terminating nul char)
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char* utf8_string = malloc(utf8_length + 1);
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char* curOutPos = utf8_string;
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if (utf8_string == NULL)
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{
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debug(LOG_ERROR, "Out of memory");
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return NULL;
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}
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curChar = unicode_string;
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while (*curChar)
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{
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curOutPos = encode_utf8_char(UTF16DecodeChar(curChar, &curChar), curOutPos);
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}
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// Terminate the string with a nul character
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utf8_string[utf8_length] = '\0';
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// Set the number of bytes allocated
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if (nbytes)
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{
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*nbytes = utf8_length + 1;
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}
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return utf8_string;
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}
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static size_t utf8_as_utf16_buf_size(const char* utf8_string)
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{
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const char* curChar = utf8_string;
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size_t length = 0;
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while (*curChar != '\0')
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{
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const utf_32_char unicode_char = UTF8DecodeChar(curChar, &curChar);
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if (unicode_char < 0x10000)
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{
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length += 1;
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}
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else if (unicode_char < 0x110000)
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{
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length += 2;
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}
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else
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{
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/* Apparently this character lies outside the 0x0 - 0x10FFFF
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* Unicode range, and UTF-16 cannot cope with that, so error
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* out.
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*/
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ASSERT(!"out-of-range Unicode codepoint", "This Unicode codepoint too large (%u > 0x10FFFF) for the UTF-16 encoding", (unsigned int)unicode_char);
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}
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}
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return length;
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}
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utf_16_char *UTF8toUTF16(const char* utf8_string, size_t *nbytes)
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{
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const char* curChar = utf8_string;
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const size_t unicode_length = utf8_as_utf16_buf_size(utf8_string);
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// Allocate memory to hold the UTF-16 encoded string (plus a terminating nul)
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utf_16_char* unicode_string = malloc(sizeof(utf_16_char) * (unicode_length + 1));
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utf_16_char* curOutPos = unicode_string;
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if (unicode_string == NULL)
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{
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debug(LOG_ERROR, "Out of memory");
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return NULL;
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}
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while (*curChar != '\0')
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{
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curOutPos = encode_utf16_char(UTF8DecodeChar(curChar, &curChar), curOutPos);
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}
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// Terminate the string with a nul
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unicode_string[unicode_length] = '\0';
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// Set the number of bytes allocated
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if (nbytes)
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{
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*nbytes = sizeof(utf_16_char) * (unicode_length + 1);
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}
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return unicode_string;
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}
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utf_16_char *UTF16CharacterAtOffset(const utf_16_char *utf16_string, size_t index)
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{
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while (*utf16_string != '\0'
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&& index != 0)
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{
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// Move to the next character
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UTF16DecodeChar(utf16_string, &utf16_string);
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--index;
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}
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if (*utf16_string == '\0')
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return NULL;
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return (utf_16_char*)utf16_string;
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}
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