/*

 * 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 "git2_util.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;

}