wcsmbs/wmemcmp.c

   1 /* Copyright (C) 1996-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <wchar.h>
  20
  21 #ifndef WMEMCMP
  22 # define WMEMCMP wmemcmp
  23 #endif
  24
  25 int
  26 WMEMCMP (const wchar_t *s1, const wchar_t *s2, size_t n)
  27 {
  28   wchar_t c1;
  29   wchar_t c2;
  30
  31   while (n >= 4)
  32     {
  33       c1 = s1[0];
  34       c2 = s2[0];
  35       if (c1 - c2 != 0)
  36         return c1 > c2 ? 1 : -1;
  37       c1 = s1[1];
  38       c2 = s2[1];
  39       if (c1 - c2 != 0)
  40         return c1 > c2 ? 1 : -1;
  41       c1 = s1[2];
  42       c2 = s2[2];
  43       if (c1 - c2 != 0)
  44         return c1 > c2 ? 1 : -1;
  45       c1 = s1[3];
  46       c2 = s2[3];
  47       if (c1 - c2 != 0)
  48         return c1 > c2 ? 1 : -1;
  49       s1 += 4;
  50       s2 += 4;
  51       n -= 4;
  52     }
  53
  54   if (n > 0)
  55     {
  56       c1 = s1[0];
  57       c2 = s2[0];
  58       if (c1 - c2 != 0)
  59         return c1 > c2 ? 1 : -1;
  60       ++s1;
  61       ++s2;
  62       --n;
  63     }
  64   if (n > 0)
  65     {
  66       c1 = s1[0];
  67       c2 = s2[0];
  68       if (c1 - c2 != 0)
  69         return c1 > c2 ? 1 : -1;
  70       ++s1;
  71       ++s2;
  72       --n;
  73     }
  74   if (n > 0)
  75     {
  76       c1 = s1[0];
  77       c2 = s2[0];
  78       if (c1 - c2 != 0)
  79         return c1 > c2 ? 1 : -1;
  80     }
  81
  82   return 0;
  83 }