thodg/libgit2/src/utf8.c

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• Hash : cb136cdd
  Author :
  Date : 2021-04-14T22:22:11
  

  utf8: introduce git_utf8_char_length Introduce a function to determine the number of Unicode characters in a given UTF-8 string.

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• src/utf8.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "utf8.h"
  
  #include "common.h"
  
  /*
   * git_utf8_iterate is taken from the utf8proc project,
   * http://www.public-software-group.org/utf8proc
   *
   * Copyright (c) 2009 Public Software Group e. V., Berlin, Germany
   *
   * 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.
   */
  
  static const uint8_t utf8proc_utf8class[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,
  	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  	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, 0, 0, 0, 0, 0, 0, 0, 0
  };
  
  static int utf8_charlen(const uint8_t *str, size_t str_len)
  {
  	uint8_t length;
  	size_t i;
  
  	length = utf8proc_utf8class[str[0]];
  	if (!length)
  		return -1;
  
  	if (str_len > 0 && length > str_len)
  		return -1;
  
  	for (i = 1; i < length; i++) {
  		if ((str[i] & 0xC0) != 0x80)
  			return -1;
  	}
  
  	return (int)length;
  }
  
  int git_utf8_iterate(uint32_t *out, const char *_str, size_t str_len)
  {
  	const uint8_t *str = (const uint8_t *)_str;
  	uint32_t uc = 0;
  	int length;
  
  	*out = 0;
  
  	if ((length = utf8_charlen(str, str_len)) < 0)
  		return -1;
  
  	switch (length) {
  		case 1:
  			uc = str[0];
  			break;
  		case 2:
  			uc = ((str[0] & 0x1F) <<  6) + (str[1] & 0x3F);
  			if (uc < 0x80) uc = -1;
  			break;
  		case 3:
  			uc = ((str[0] & 0x0F) << 12) + ((str[1] & 0x3F) <<  6)
  				+ (str[2] & 0x3F);
  			if (uc < 0x800 || (uc >= 0xD800 && uc < 0xE000) ||
  					(uc >= 0xFDD0 && uc < 0xFDF0)) uc = -1;
  			break;
  		case 4:
  			uc = ((str[0] & 0x07) << 18) + ((str[1] & 0x3F) << 12)
  				+ ((str[2] & 0x3F) <<  6) + (str[3] & 0x3F);
  			if (uc < 0x10000 || uc >= 0x110000) uc = -1;
  			break;
  		default:
  			return -1;
  	}
  
  	if ((uc & 0xFFFF) >= 0xFFFE)
  		return -1;
  
  	*out = uc;
  	return length;
  }
  
  size_t git_utf8_char_length(const char *_str, size_t str_len)
  {
  	const uint8_t *str = (const uint8_t *)_str;
  	size_t offset = 0, count = 0;
  
  	while (offset < str_len) {
  		int length = utf8_charlen(str + offset, str_len - offset);
  
  		if (length < 0)
  			length = 1;
  
  		offset += length;
  		count++;
  	}
  
  	return count;
  }
  
  size_t git_utf8_valid_buf_length(const char *_str, size_t str_len)
  {
  	const uint8_t *str = (const uint8_t *)_str;
  	size_t offset = 0;
  
  	while (offset < str_len) {
  		int length = utf8_charlen(str + offset, str_len - offset);
  
  		if (length < 0)
  			break;
  
  		offset += length;
  	}
  
  	return offset;
  }
  

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