wcsmbs/wmemcmp.c

   1 /* Copyright (C) 1996-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <wchar.h>
  19
  20 #ifdef WMEMCMP
  21 # define __wmemcmp WMEMCMP
  22 #endif
  23
  24 int
  25 __wmemcmp (const wchar_t *s1, const wchar_t *s2, size_t n)
  26 {
  27   wchar_t c1;
  28   wchar_t c2;
  29
  30   while (n >= 4)
  31     {
  32       c1 = s1[0];
  33       c2 = s2[0];
  34       if (c1 - c2 != 0)
  35         return c1 > c2 ? 1 : -1;
  36       c1 = s1[1];
  37       c2 = s2[1];
  38       if (c1 - c2 != 0)
  39         return c1 > c2 ? 1 : -1;
  40       c1 = s1[2];
  41       c2 = s2[2];
  42       if (c1 - c2 != 0)
  43         return c1 > c2 ? 1 : -1;
  44       c1 = s1[3];
  45       c2 = s2[3];
  46       if (c1 - c2 != 0)
  47         return c1 > c2 ? 1 : -1;
  48       s1 += 4;
  49       s2 += 4;
  50       n -= 4;
  51     }
  52
  53   if (n > 0)
  54     {
  55       c1 = s1[0];
  56       c2 = s2[0];
  57       if (c1 - c2 != 0)
  58         return c1 > c2 ? 1 : -1;
  59       ++s1;
  60       ++s2;
  61       --n;
  62     }
  63   if (n > 0)
  64     {
  65       c1 = s1[0];
  66       c2 = s2[0];
  67       if (c1 - c2 != 0)
  68         return c1 > c2 ? 1 : -1;
  69       ++s1;
  70       ++s2;
  71       --n;
  72     }
  73   if (n > 0)
  74     {
  75       c1 = s1[0];
  76       c2 = s2[0];
  77       if (c1 - c2 != 0)
  78         return c1 > c2 ? 1 : -1;
  79     }
  80
  81   return 0;
  82 }
  83 #ifndef WMEMCMP
  84 weak_alias (__wmemcmp, wmemcmp)
  85 #endif