1  /* Copyright (C) 1991-2023 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     <https://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 , locale_t loc
      38  #else
      39  # define LOCALE_PARAM
      40  #endif
      41  
      42  /* Compare S1 and S2, ignoring case, returning less than, equal to or
      43     greater than zero if S1 is lexicographically less than,
      44     equal to or greater than S2.  */
      45  int
      46  __strcasecmp (const char *s1, const char *s2 LOCALE_PARAM)
      47  {
      48  #if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
      49    locale_t loc = _NL_CURRENT_LOCALE;
      50  #endif
      51    const unsigned char *p1 = (const unsigned char *) s1;
      52    const unsigned char *p2 = (const unsigned char *) s2;
      53    int result;
      54  
      55    if (p1 == p2)
      56      return 0;
      57  
      58    while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
      59      if (*p1++ == '\0')
      60        break;
      61  
      62    return result;
      63  }
      64  #ifndef __strcasecmp
      65  libc_hidden_def (__strcasecmp)
      66  weak_alias (__strcasecmp, strcasecmp)
      67  #endif