strrevcmp.c revision 98121 
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>
12SM_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 */
19extern 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
32int
33sm_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
74int
75sm_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}
102