string/strcasecmp.c

   1 /* Copyright (C) 1991,1992,1995,1996,1997,2001,2002, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 #ifdef HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #include <ctype.h>
  24 #include <string.h>
  25
  26 #ifndef _LIBC
  27 # define __strcasecmp strcasecmp
  28 # define TOLOWER(Ch) tolower (Ch)
  29 #else
  30 # include <locale/localeinfo.h>
  31 # ifdef USE_IN_EXTENDED_LOCALE_MODEL
  32 #  define __strcasecmp __strcasecmp_l
  33 # endif
  34 # define TOLOWER(Ch) __tolower_l ((Ch), loc)
  35 #endif
  36
  37 #ifdef USE_IN_EXTENDED_LOCALE_MODEL
  38 # define LOCALE_PARAM , loc
  39 # define LOCALE_PARAM_DECL __locale_t loc;
  40 #else
  41 # define LOCALE_PARAM
  42 # define LOCALE_PARAM_DECL
  43 #endif
  44
  45 /* Compare S1 and S2, ignoring case, returning less than, equal to or
  46    greater than zero if S1 is lexicographically less than,
  47    equal to or greater than S2.  */
  48 int
  49 __strcasecmp (s1, s2 LOCALE_PARAM)
  50      const char *s1;
  51      const char *s2;
  52      LOCALE_PARAM_DECL
  53 {
  54 #if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
  55   __locale_t loc = _NL_CURRENT_LOCALE;
  56 #endif
  57   const unsigned char *p1 = (const unsigned char *) s1;
  58   const unsigned char *p2 = (const unsigned char *) s2;
  59   int result;
  60
  61   if (p1 == p2)
  62     return 0;
  63
  64   while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
  65     if (*p1++ == '\0')
  66       break;
  67
  68   return result;
  69 }
  70 #ifndef __strcasecmp
  71 libc_hidden_def (__strcasecmp)
  72 weak_alias (__strcasecmp, strcasecmp)
  73 #endif