maint/gnulib/lib/unistr/u8-strmbtouc.c

/* */
This source file includes following definitions.
u8_strmbtouc
   1 /* Look at first character in UTF-8 string.
   2    Copyright (C) 1999-2000, 2002, 2006-2007, 2009-2021 Free Software
   3    Foundation, Inc.
   4    Written by Bruno Haible <bruno@clisp.org>, 2002.
   5 
   6    This file is free software.
   7    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   8    You can redistribute it and/or modify it under either
   9      - the terms of the GNU Lesser General Public License as published
  10        by the Free Software Foundation; either version 3, or (at your
  11        option) any later version, or
  12      - the terms of the GNU General Public License as published by the
  13        Free Software Foundation; either version 2, or (at your option)
  14        any later version, or
  15      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  16 
  17    This file is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20    Lesser General Public License and the GNU General Public License
  21    for more details.
  22 
  23    You should have received a copy of the GNU Lesser General Public
  24    License and of the GNU General Public License along with this
  25    program.  If not, see <https://www.gnu.org/licenses/>.  */
  26 
  27 #include <config.h>
  28 
  29 /* Specification.  */
  30 #include "unistr.h"
  31 
  32 int
  33 u8_strmbtouc (ucs4_t *puc, const uint8_t *s)
     /*  */
  34 {
  35   /* Keep in sync with unistr.h and u8-mbtouc-aux.c.  */
  36   uint8_t c = *s;
  37 
  38   if (c < 0x80)
  39     {
  40       *puc = c;
  41       return (c != 0 ? 1 : 0);
  42     }
  43   if (c >= 0xc2)
  44     {
  45       if (c < 0xe0)
  46         {
  47           if ((s[1] ^ 0x80) < 0x40)
  48             {
  49               *puc = ((unsigned int) (c & 0x1f) << 6)
  50                      | (unsigned int) (s[1] ^ 0x80);
  51               return 2;
  52             }
  53         }
  54       else if (c < 0xf0)
  55         {
  56           if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
  57               && (c >= 0xe1 || s[1] >= 0xa0)
  58               && (c != 0xed || s[1] < 0xa0))
  59             {
  60               *puc = ((unsigned int) (c & 0x0f) << 12)
  61                      | ((unsigned int) (s[1] ^ 0x80) << 6)
  62                      | (unsigned int) (s[2] ^ 0x80);
  63               return 3;
  64             }
  65         }
  66       else if (c < 0xf8)
  67         {
  68           if ((s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
  69               && (s[3] ^ 0x80) < 0x40
  70               && (c >= 0xf1 || s[1] >= 0x90)
  71               && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90)))
  72             {
  73               *puc = ((unsigned int) (c & 0x07) << 18)
  74                      | ((unsigned int) (s[1] ^ 0x80) << 12)
  75                      | ((unsigned int) (s[2] ^ 0x80) << 6)
  76                      | (unsigned int) (s[3] ^ 0x80);
  77               return 4;
  78             }
  79         }
  80     }
  81   /* invalid or incomplete multibyte character */
  82   return -1;
  83 }
/* */
root/maint/gnulib/lib/unistr/u8-strmbtouc.c

DEFINITIONS
