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

/* */
This source file includes following definitions.
u16_cmp
   1 /* Compare pieces of UTF-16 strings.
   2    Copyright (C) 1999, 2002, 2006, 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 int
  32 u16_cmp (const uint16_t *s1, const uint16_t *s2, size_t n)
     /*  */
  33 {
  34   /* Note that the UTF-16 encoding does NOT preserve lexicographic order.
  35      Namely, if uc1 is a 16-bit character and [uc2a,uc2b] is a surrogate pair,
  36      we must enforce uc1 < [uc2a,uc2b], even if uc1 > uc2a.  */
  37   for (; n > 0;)
  38     {
  39       uint16_t c1 = *s1++;
  40       uint16_t c2 = *s2++;
  41       if (c1 == c2)
  42         {
  43           n--;
  44           continue;
  45         }
  46       if (c1 < 0xd800 || c1 >= 0xe000)
  47         {
  48           if (!(c2 < 0xd800 || c2 >= 0xe000))
  49             /* c2 is a surrogate, but c1 is not.  */
  50             return -1;
  51         }
  52       else
  53         {
  54           if (c2 < 0xd800 || c2 >= 0xe000)
  55             /* c1 is a surrogate, but c2 is not.  */
  56             return 1;
  57         }
  58       return (int)c1 - (int)c2;
  59       /* > 0 if c1 > c2, < 0 if c1 < c2. */
  60     }
  61   return 0;
  62 }
/* */
root/maint/gnulib/lib/unistr/u16-cmp.c

DEFINITIONS
