Line data    Source code

       1             : /* Case-insensitive string comparison function.
       2             :    Copyright (C) 1998-1999, 2005-2007 Free Software Foundation, Inc.
       3             :    Written by Bruno Haible <bruno@clisp.org>, 2005,
       4             :    based on earlier glibc code.
       5             : 
       6             :    This program is free software: you can redistribute it and/or modify
       7             :    it under the terms of the GNU General Public License as published by
       8             :    the Free Software Foundation; either version 3 of the License, or
       9             :    (at your option) any later version.
      10             : 
      11             :    This program 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
      14             :    GNU General Public License for more details.
      15             : 
      16             :    You should have received a copy of the GNU General Public License
      17             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      18             : 
      19             : #include <config.h>
      20             : 
      21             : /* Specification.  */
      22             : #include <string.h>
      23             : 
      24             : #include <ctype.h>
      25             : #include <limits.h>
      26             : 
      27             : #if HAVE_MBRTOWC
      28             : # include "mbuiter.h"
      29             : #endif
      30             : 
      31             : #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
      32             : 
      33             : /* Compare the character strings S1 and S2, ignoring case, returning less than,
      34             :    equal to or greater than zero if S1 is lexicographically less than, equal to
      35             :    or greater than S2.
      36             :    Note: This function may, in multibyte locales, return 0 for strings of
      37             :    different lengths!  */
      38             : int
      39           0 : mbscasecmp (const char *s1, const char *s2)
      40             : {
      41           0 :   if (s1 == s2)
      42           0 :     return 0;
      43             : 
      44             :   /* Be careful not to look at the entire extent of s1 or s2 until needed.
      45             :      This is useful because when two strings differ, the difference is
      46             :      most often already in the very few first characters.  */
      47             : #if HAVE_MBRTOWC
      48           0 :   if (MB_CUR_MAX > 1)
      49             :     {
      50             :       mbui_iterator_t iter1;
      51             :       mbui_iterator_t iter2;
      52             : 
      53           0 :       mbui_init (iter1, s1);
      54           0 :       mbui_init (iter2, s2);
      55             : 
      56           0 :       while (mbui_avail (iter1) && mbui_avail (iter2))
      57             :         {
      58           0 :           int cmp = mb_casecmp (mbui_cur (iter1), mbui_cur (iter2));
      59             : 
      60           0 :           if (cmp != 0)
      61           0 :             return cmp;
      62             : 
      63           0 :           mbui_advance (iter1);
      64           0 :           mbui_advance (iter2);
      65             :         }
      66           0 :       if (mbui_avail (iter1))
      67             :         /* s2 terminated before s1.  */
      68           0 :         return 1;
      69           0 :       if (mbui_avail (iter2))
      70             :         /* s1 terminated before s2.  */
      71           0 :         return -1;
      72           0 :       return 0;
      73             :     }
      74             :   else
      75             : #endif
      76             :     {
      77           0 :       const unsigned char *p1 = (const unsigned char *) s1;
      78           0 :       const unsigned char *p2 = (const unsigned char *) s2;
      79             :       unsigned char c1, c2;
      80             : 
      81             :       do
      82             :         {
      83           0 :           c1 = TOLOWER (*p1);
      84           0 :           c2 = TOLOWER (*p2);
      85             : 
      86           0 :           if (c1 == '\0')
      87           0 :             break;
      88             : 
      89           0 :           ++p1;
      90           0 :           ++p2;
      91             :         }
      92           0 :       while (c1 == c2);
      93             : 
      94             :       if (UCHAR_MAX <= INT_MAX)
      95           0 :         return c1 - c2;
      96             :       else
      97             :         /* On machines where 'char' and 'int' are types of the same size, the
      98             :            difference of two 'unsigned char' values - including the sign bit -
      99             :            doesn't fit in an 'int'.  */
     100             :         return (c1 > c2 ? 1 : c1 < c2 ? -1 : 0);
     101             :     }
     102             : }