string/strncase.c

   1 /* Compare at most N characters of two strings without taking care for
   2    the case.
   3    Copyright (C) 1992, 1996, 1997, 2001, 2004 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <string.h>
  26 #include <ctype.h>
  27
  28 #ifndef weak_alias
  29 # define __strncasecmp strncasecmp
  30 # define TOLOWER(Ch) tolower (Ch)
  31 #else
  32 # include <locale/localeinfo.h>
  33 # ifdef USE_IN_EXTENDED_LOCALE_MODEL
  34 #  define __strncasecmp __strncasecmp_l
  35 # endif
  36 # define TOLOWER(Ch) __tolower_l ((Ch), loc)
  37 #endif
  38
  39 #ifdef USE_IN_EXTENDED_LOCALE_MODEL
  40 # define LOCALE_PARAM , loc
  41 # define LOCALE_PARAM_DECL __locale_t loc;
  42 #else
  43 # define LOCALE_PARAM
  44 # define LOCALE_PARAM_DECL
  45 #endif
  46
  47 /* Compare no more than N characters of S1 and S2,
  48    ignoring case, returning less than, equal to or
  49    greater than zero if S1 is lexicographically less
  50    than, equal to or greater than S2.  */
  51 int
  52 __strncasecmp (s1, s2, n LOCALE_PARAM)
  53      const char *s1;
  54      const char *s2;
  55      size_t n;
  56      LOCALE_PARAM_DECL
  57 {
  58 #if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
  59   __locale_t loc = _NL_CURRENT_LOCALE;
  60 #endif
  61   const unsigned char *p1 = (const unsigned char *) s1;
  62   const unsigned char *p2 = (const unsigned char *) s2;
  63   int result;
  64
  65   if (p1 == p2 || n == 0)
  66     return 0;
  67
  68   while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
  69     if (*p1++ == '\0' || --n == 0)
  70       break;
  71
  72   return result;
  73 }
  74 #ifndef __strncasecmp
  75 weak_alias (__strncasecmp, strncasecmp)
  76 #endif