lib/mbmemcasecmp.c

   1 /* Compare two memory areas with possibly different lengths, case-insensitive.
   2    Copyright (C) 1998-1999, 2005-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2009,
   4    based on earlier glibc code.
   5
   6    This file is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation, either version 3 of the
   9    License, or (at your option) any later version.
  10
  11    This file 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 Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public License
  17    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "mbmemcasecmp.h"
  23
  24 #include <ctype.h>
  25 #include <limits.h>
  26 #include <stdlib.h>
  27
  28 #if GNULIB_MCEL_PREFER
  29 # include "mcel.h"
  30 #else
  31 # include "mbiterf.h"
  32 #endif
  33
  34 int
  35 mbmemcasecmp (const char *s1, size_t n1, const char *s2, size_t n2)
  36 {
  37   if (s1 == s2)
  38     return _GL_CMP (n1, n2);
  39
  40   const char *iter1 = s1;
  41   const char *iter2 = s2;
  42   const char *s1_end = s1 + n1;
  43   const char *s2_end = s2 + n2;
  44
  45   if (MB_CUR_MAX > 1)
  46     {
  47 #if GNULIB_MCEL_PREFER
  48       while ((iter1 < s1_end) & (iter2 < s2_end))
  49         {
  50           mcel_t g1 = mcel_scan (iter1, s1_end); iter1 += g1.len;
  51           mcel_t g2 = mcel_scan (iter2, s2_end); iter2 += g2.len;
  52           int cmp = mcel_tocmp (c32tolower, g1, g2);
  53           if (cmp)
  54             return cmp;
  55         }
  56       return (iter1 < s1_end) - (iter2 < s2_end);
  57 #else
  58       mbif_state_t state1;
  59       mbif_init (state1);
  60
  61       mbif_state_t state2;
  62       mbif_init (state2);
  63
  64       while (mbif_avail (state1, iter1, s1_end)
  65              && mbif_avail (state2, iter2, s2_end))
  66         {
  67           mbchar_t cur1 = mbif_next (state1, iter1, s1_end);
  68           mbchar_t cur2 = mbif_next (state2, iter2, s2_end);
  69           int cmp = mb_casecmp (cur1, cur2);
  70
  71           if (cmp != 0)
  72             return cmp;
  73
  74           iter1 += mb_len (cur1);
  75           iter2 += mb_len (cur2);
  76         }
  77       if (mbif_avail (state1, iter1, s1_end))
  78         /* s2 terminated before s1.  */
  79         return 1;
  80       if (mbif_avail (state2, iter2, s2_end))
  81         /* s1 terminated before s2.  */
  82         return -1;
  83       return 0;
  84 #endif
  85     }
  86   else
  87     {
  88       while (iter1 < s1_end && iter2 < s2_end)
  89         {
  90           unsigned char c1 = *iter1++;
  91           unsigned char c2 = *iter2++;
  92           /* On machines where 'char' and 'int' are types of the same size,
  93              the difference of two 'unsigned char' values - including
  94              the sign bit - doesn't fit in an 'int'.  */
  95           int cmp = UCHAR_MAX <= INT_MAX ? c1 - c2 : _GL_CMP (c1, c2);
  96           if (cmp != 0)
  97             {
  98               c1 = tolower (c1);
  99               if (c1 != c2)
 100                 {
 101                   c2 = tolower (c2);
 102                   cmp = UCHAR_MAX <= INT_MAX ? c1 - c2 : _GL_CMP (c1, c2);
 103                   if (cmp != 0)
 104                     return cmp;
 105                 }
 106             }
 107         }
 108       if (iter1 < s1_end)
 109         /* s2 terminated before s1.  */
 110         return 1;
 111       if (iter2 < s2_end)
 112         /* s1 terminated before s2.  */
 113         return -1;
 114       return 0;
 115     }
 116 }