contrib/sendmail/libsm/strrevcmp.c

   1 /*
   2  * Copyright (c) 2001 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  *
   5  * By using this file, you agree to the terms and conditions set
   6  * forth in the LICENSE file which can be found at the top level of
   7  * the sendmail distribution.
   8  *
   9  */
  10
  11 #include <sm/gen.h>
  12 SM_RCSID("@(#)$Id: strrevcmp.c,v 1.5 2001/09/11 04:04:49 gshapiro Exp $")
  13
  14 #include <sm/config.h>
  15 #include <sm/string.h>
  16 #include <string.h>
  17
  18 /* strcasecmp.c */
  19 extern const unsigned char charmap[];
  20
  21 /*
  22 **  SM_STRREVCASECMP -- compare two strings starting at the end (ignore case)
  23 **
  24 **      Parameters:
  25 **              s1 -- first string.
  26 **              s2 -- second string.
  27 **
  28 **      Returns:
  29 **              strcasecmp(reverse(s1), reverse(s2))
  30 */
  31
  32 int
  33 sm_strrevcasecmp(s1, s2)
  34         const char *s1, *s2;
  35 {
  36         register int i1, i2;
  37
  38         i1 = strlen(s1) - 1;
  39         i2 = strlen(s2) - 1;
  40         while (i1 >= 0 && i2 >= 0 &&
  41                charmap[(unsigned char) s1[i1]] ==
  42                charmap[(unsigned char) s2[i2]])
  43         {
  44                 --i1;
  45                 --i2;
  46         }
  47         if (i1 < 0)
  48         {
  49                 if (i2 < 0)
  50                         return 0;
  51                 else
  52                         return -1;
  53         }
  54         else
  55         {
  56                 if (i2 < 0)
  57                         return 1;
  58                 else
  59                         return (charmap[(unsigned char) s1[i1]] -
  60                                 charmap[(unsigned char) s2[i2]]);
  61         }
  62 }
  63 /*
  64 **  SM_STRREVCMP -- compare two strings starting at the end
  65 **
  66 **      Parameters:
  67 **              s1 -- first string.
  68 **              s2 -- second string.
  69 **
  70 **      Returns:
  71 **              strcmp(reverse(s1), reverse(s2))
  72 */
  73
  74 int
  75 sm_strrevcmp(s1, s2)
  76         const char *s1, *s2;
  77 {
  78         register int i1, i2;
  79
  80         i1 = strlen(s1) - 1;
  81         i2 = strlen(s2) - 1;
  82         while (i1 >= 0 && i2 >= 0 && s1[i1] == s2[i2])
  83         {
  84                 --i1;
  85                 --i2;
  86         }
  87         if (i1 < 0)
  88         {
  89                 if (i2 < 0)
  90                         return 0;
  91                 else
  92                         return -1;
  93         }
  94         else
  95         {
  96                 if (i2 < 0)
  97                         return 1;
  98                 else
  99                         return s1[i1] - s2[i2];
 100         }
 101 }