sendmail/libsm/strrevcmp.c

/*
 * Copyright (c) 2001 Sendmail, Inc. and its suppliers.
 *  All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: strrevcmp.c,v 1.2 2001/08/27 22:21:51 gshapiro Exp $")

#include <sm/config.h>
#include <sm/string.h>
#include <string.h>

/* strcasecmp.c */
extern const unsigned char charmap[];

/*
**  SM_STRREVCASECMP -- compare two strings starting at the end (ignore case)
**
**  Parameters:
**      s1 -- first string.
**      s2 -- second string.
**
**  Returns:
**      strcasecmp(reverse(s1), reverse(s2))
*/

int
sm_strrevcasecmp(s1, s2)
    const char *s1, *s2;
{
    register int i1, i2;

    i1 = strlen(s1) - 1;
    i2 = strlen(s2) - 1;
    while (i1 >= 0 && i2 >= 0 &&
           charmap[(unsigned char) s1[i1]] ==
           charmap[(unsigned char) s2[i2]])
    {
        --i1;
        --i2;
    }
    if (i1 < 0)
    {
        if (i2 < 0)
            return 0;
        else
            return -1;
    }
    else
    {
        if (i2 < 0)
            return 1;
        else
            return (charmap[(unsigned char) s1[i1]] -
                charmap[(unsigned char) s2[i2]]);
    }
}
/*
**  SM_STRREVCMP -- compare two strings starting at the end
**
**  Parameters:
**      s1 -- first string.
**      s2 -- second string.
**
**  Returns:
**      strcmp(reverse(s1), reverse(s2))
*/

int
sm_strrevcmp(s1, s2)
    const char *s1, *s2;
{
    register int i1, i2;

    i1 = strlen(s1) - 1;
    i2 = strlen(s2) - 1;
    while (i1 >= 0 && i2 >= 0 && s1[i1] == s2[i2])
    {
        --i1;
        --i2;
    }
    if (i1 < 0)
    {
        if (i2 < 0)
            return 0;
        else
            return -1;
    }
    else
    {
        if (i2 < 0)
            return 1;
        else
            return s1[i1] - s2[i2];
    }
}