kc3-lang/gnulib/lib/unistr/u8-strmbtouc.c

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• Hash : 32a72f45
  Author :
  Date : 2023-01-01T01:14:21
  

  maint: run 'make update-copyright'
  

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• lib/unistr/u8-strmbtouc.c

• /* Look at first character in UTF-8 string.
     Copyright (C) 1999-2000, 2002, 2006-2007, 2009-2023 Free Software
     Foundation, Inc.
     Written by Bruno Haible <bruno@clisp.org>, 2002.
  
     This file is free software.
     It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
     You can redistribute it and/or modify it under either
       - the terms of the GNU Lesser General Public License as published
         by the Free Software Foundation, either version 3, or (at your
         option) any later version, or
       - the terms of the GNU General Public License as published by the
         Free Software Foundation; either version 2, or (at your option)
         any later version, or
       - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  
     This file is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License and the GNU General Public License
     for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License and of the GNU General Public License along with this
     program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include "unistr.h"
  
  int
  u8_strmbtouc (ucs4_t *puc, const uint8_t *s)
  {
    /* Keep in sync with unistr.h and u8-mbtouc-aux.c.  */
    uint8_t c = *s;
  
    if (c < 0x80)
      {
        *puc = c;
        return (c != 0 ? 1 : 0);
      }
    if (c >= 0xc2)
      {
        if (c < 0xe0)
          {
            if ((s[1] ^ 0x80) < 0x40)
              {
                *puc = ((unsigned int) (c & 0x1f) << 6)
                       | (unsigned int) (s[1] ^ 0x80);
                return 2;
              }
          }
        else if (c < 0xf0)
          {
            if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
                && (c >= 0xe1 || s[1] >= 0xa0)
                && (c != 0xed || s[1] < 0xa0))
              {
                *puc = ((unsigned int) (c & 0x0f) << 12)
                       | ((unsigned int) (s[1] ^ 0x80) << 6)
                       | (unsigned int) (s[2] ^ 0x80);
                return 3;
              }
          }
        else if (c < 0xf8)
          {
            if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
                && (s[3] ^ 0x80) < 0x40
                && (c >= 0xf1 || s[1] >= 0x90)
                && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90)))
              {
                *puc = ((unsigned int) (c & 0x07) << 18)
                       | ((unsigned int) (s[1] ^ 0x80) << 12)
                       | ((unsigned int) (s[2] ^ 0x80) << 6)
                       | (unsigned int) (s[3] ^ 0x80);
                return 4;
              }
          }
      }
    /* invalid or incomplete multibyte character */
    return -1;
  }
  

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