usr/src/cmd/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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  12
  13 #include <sm/gen.h>
  14 SM_RCSID("@(#)$Id: strrevcmp.c,v 1.2 2001/08/27 22:21:51 gshapiro Exp $")
  15
  16 #include <sm/config.h>
  17 #include <sm/string.h>
  18 #include <string.h>
  19
  20 /* strcasecmp.c */
  21 extern const unsigned char charmap[];
  22
  23 /*
  24 **  SM_STRREVCASECMP -- compare two strings starting at the end (ignore case)
  25 **
  26 **      Parameters:
  27 **              s1 -- first string.
  28 **              s2 -- second string.
  29 **
  30 **      Returns:
  31 **              strcasecmp(reverse(s1), reverse(s2))
  32 */
  33
  34 int
  35 sm_strrevcasecmp(s1, s2)
  36         const char *s1, *s2;
  37 {
  38         register int i1, i2;
  39
  40         i1 = strlen(s1) - 1;
  41         i2 = strlen(s2) - 1;
  42         while (i1 >= 0 && i2 >= 0 &&
  43                charmap[(unsigned char) s1[i1]] ==
  44                charmap[(unsigned char) s2[i2]])
  45         {
  46                 --i1;
  47                 --i2;
  48         }
  49         if (i1 < 0)
  50         {
  51                 if (i2 < 0)
  52                         return 0;
  53                 else
  54                         return -1;
  55         }
  56         else
  57         {
  58                 if (i2 < 0)
  59                         return 1;
  60                 else
  61                         return (charmap[(unsigned char) s1[i1]] -
  62                                 charmap[(unsigned char) s2[i2]]);
  63         }
  64 }
  65 \f/*
  66 **  SM_STRREVCMP -- compare two strings starting at the end
  67 **
  68 **      Parameters:
  69 **              s1 -- first string.
  70 **              s2 -- second string.
  71 **
  72 **      Returns:
  73 **              strcmp(reverse(s1), reverse(s2))
  74 */
  75
  76 int
  77 sm_strrevcmp(s1, s2)
  78         const char *s1, *s2;
  79 {
  80         register int i1, i2;
  81
  82         i1 = strlen(s1) - 1;
  83         i2 = strlen(s2) - 1;
  84         while (i1 >= 0 && i2 >= 0 && s1[i1] == s2[i2])
  85         {
  86                 --i1;
  87                 --i2;
  88         }
  89         if (i1 < 0)
  90         {
  91                 if (i2 < 0)
  92                         return 0;
  93                 else
  94                         return -1;
  95         }
  96         else
  97         {
  98                 if (i2 < 0)
  99                         return 1;
 100                 else
 101                         return s1[i1] - s2[i2];
 102         }
 103 }