sysdeps/generic/strcasecmp.c

   1 /* Copyright (C) 1991, 1992, 1995, 1996, 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifdef HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #include <ctype.h>
  24 #include <string.h>
  25
  26 #ifndef weak_alias
  27 # define __strcasecmp strcasecmp
  28 #endif
  29
  30 /* Compare S1 and S2, ignoring case, returning less than, equal to or
  31    greater than zero if S1 is lexicographically less than,
  32    equal to or greater than S2.  */
  33 int
  34 __strcasecmp (s1, s2)
  35      const char *s1;
  36      const char *s2;
  37 {
  38   const unsigned char *p1 = (const unsigned char *) s1;
  39   const unsigned char *p2 = (const unsigned char *) s2;
  40   unsigned char c1, c2;
  41
  42   if (p1 == p2)
  43     return 0;
  44
  45   do
  46     {
  47       c1 = tolower (*p1++);
  48       c2 = tolower (*p2++);
  49       if (c1 == '\0')
  50         break;
  51     }
  52   while (c1 == c2);
  53
  54   return c1 - c2;
  55 }
  56 #ifdef weak_alias
  57 weak_alias (__strcasecmp, strcasecmp)
  58 #endif