string/strcasecmp.c

   1 /* Copyright (C) 1991-2014 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifdef HAVE_CONFIG_H
  19 # include <config.h>
  20 #endif
  21
  22 #include <ctype.h>
  23 #include <string.h>
  24
  25 #ifndef _LIBC
  26 # define __strcasecmp strcasecmp
  27 # define TOLOWER(Ch) tolower (Ch)
  28 #else
  29 # include <locale/localeinfo.h>
  30 # ifdef USE_IN_EXTENDED_LOCALE_MODEL
  31 #  define __strcasecmp __strcasecmp_l
  32 # endif
  33 # define TOLOWER(Ch) __tolower_l ((Ch), loc)
  34 #endif
  35
  36 #ifdef USE_IN_EXTENDED_LOCALE_MODEL
  37 # define LOCALE_PARAM , loc
  38 # define LOCALE_PARAM_DECL __locale_t loc;
  39 #else
  40 # define LOCALE_PARAM
  41 # define LOCALE_PARAM_DECL
  42 #endif
  43
  44 /* Compare S1 and S2, ignoring case, returning less than, equal to or
  45    greater than zero if S1 is lexicographically less than,
  46    equal to or greater than S2.  */
  47 int
  48 __strcasecmp (s1, s2 LOCALE_PARAM)
  49      const char *s1;
  50      const char *s2;
  51      LOCALE_PARAM_DECL
  52 {
  53 #if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
  54   __locale_t loc = _NL_CURRENT_LOCALE;
  55 #endif
  56   const unsigned char *p1 = (const unsigned char *) s1;
  57   const unsigned char *p2 = (const unsigned char *) s2;
  58   int result;
  59
  60   if (p1 == p2)
  61     return 0;
  62
  63   while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
  64     if (*p1++ == '\0')
  65       break;
  66
  67   return result;
  68 }
  69 #ifndef __strcasecmp
  70 libc_hidden_def (__strcasecmp)
  71 weak_alias (__strcasecmp, strcasecmp)
  72 #endif