maint/gnulib/lib/unistr/u16-prev.c

/* */
This source file includes following definitions.
u16_prev
   1 /* Iterate over previous character in UTF-16 string.
   2    Copyright (C) 2002, 2006-2007, 2009-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2002.
   4 
   5    This file is free software.
   6    It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
   7    You can redistribute it and/or modify it under either
   8      - the terms of the GNU Lesser General Public License as published
   9        by the Free Software Foundation; either version 3, or (at your
  10        option) any later version, or
  11      - the terms of the GNU General Public License as published by the
  12        Free Software Foundation; either version 2, or (at your option)
  13        any later version, or
  14      - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
  15 
  16    This file is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19    Lesser General Public License and the GNU General Public License
  20    for more details.
  21 
  22    You should have received a copy of the GNU Lesser General Public
  23    License and of the GNU General Public License along with this
  24    program.  If not, see <https://www.gnu.org/licenses/>.  */
  25 
  26 #include <config.h>
  27 
  28 /* Specification.  */
  29 #include "unistr.h"
  30 
  31 const uint16_t *
  32 u16_prev (ucs4_t *puc, const uint16_t *s, const uint16_t *start)
     /*  */
  33 {
  34   /* Keep in sync with unistr.h and utf16-ucs4.c.  */
  35   if (s != start)
  36     {
  37       uint16_t c_1 = s[-1];
  38 
  39       if (c_1 < 0xd800 || c_1 >= 0xe000)
  40         {
  41           *puc = c_1;
  42           return s - 1;
  43         }
  44       if (c_1 >= 0xdc00)
  45         if (s - 1 != start)
  46           {
  47             uint16_t c_2 = s[-2];
  48 
  49             if (c_2 >= 0xd800 && c_2 < 0xdc00)
  50               {
  51                 *puc = 0x10000 + ((c_2 - 0xd800) << 10) + (c_1 - 0xdc00);
  52                 return s - 2;
  53               }
  54           }
  55     }
  56   return NULL;
  57 }
/* */
root/maint/gnulib/lib/unistr/u16-prev.c

DEFINITIONS
