match.c revision 1.2 
1/*
2
3match.c
4
5Author: Tatu Ylonen <ylo@cs.hut.fi>
6
7Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8                   All rights reserved
9
10Created: Thu Jun 22 01:17:50 1995 ylo
11
12Simple pattern matching, with '*' and '?' as wildcards.
13
14*/
15
16#include "includes.h"
17RCSID("$Id: match.c,v 1.2 1999/11/23 22:25:54 markus Exp $");
18
19#include "ssh.h"
20
21/* Returns true if the given string matches the pattern (which may contain
22   ? and * as wildcards), and zero if it does not match. */
23
24int
25match_pattern(const char *s, const char *pattern)
26{
27	for (;;) {
28		/* If at end of pattern, accept if also at end of string. */
29		if (!*pattern)
30			return !*s;
31
32		/* Process '*'. */
33		if (*pattern == '*') {
34			/* Skip the asterisk. */
35			pattern++;
36
37			/* If at end of pattern, accept immediately. */
38			if (!*pattern)
39				return 1;
40
41			/* If next character in pattern is known, optimize. */
42			if (*pattern != '?' && *pattern != '*') {
43				/* Look instances of the next character in
44				   pattern, and try to match starting from
45				   those. */
46				for (; *s; s++)
47					if (*s == *pattern &&
48					    match_pattern(s + 1, pattern + 1))
49						return 1;
50				/* Failed. */
51				return 0;
52			}
53			/* Move ahead one character at a time and try to
54			   match at each position. */
55			for (; *s; s++)
56				if (match_pattern(s, pattern))
57					return 1;
58			/* Failed. */
59			return 0;
60		}
61		/* There must be at least one more character in the
62		   string.  If we are at the end, fail. */
63		if (!*s)
64			return 0;
65
66		/* Check if the next character of the string is
67		   acceptable. */
68		if (*pattern != '?' && *pattern != *s)
69			return 0;
70
71		/* Move to the next character, both in string and in
72		   pattern. */
73		s++;
74		pattern++;
75	}
76	/* NOTREACHED */
77}
78