1 /* $XConsortium: wildmat.c,v 1.2 94/04/13 18:40:59 rws Exp $ */
4 ** Do shell-style pattern matching for ?, \, [], and * characters.
5 ** Might not be robust in face of malformed patterns; e.g., "foo[a-"
6 ** could cause a segmentation violation. It is 8bit clean.
8 ** Written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
9 ** Rich $alz is now <rsalz@bbn.com>.
10 ** April, 1991: Replaced mutually-recursive calls with in-line code
11 ** for the star character.
13 ** Special thanks to Lars Mathiesen <thorinn@diku.dk> for the ABORT code.
14 ** This can greatly speed up failing wildcard patterns. For example:
15 ** pattern: -*-*-*-*-*-*-12-*-*-*-m-*-*-*
16 ** text 1: -adobe-courier-bold-o-normal--12-120-75-75-m-70-iso8859-1
17 ** text 2: -adobe-courier-bold-o-normal--12-120-75-75-X-70-iso8859-1
18 ** Text 1 matches with 51 calls, while text 2 fails with 54 calls. Without
19 ** the ABORT, then it takes 22310 calls to fail. Ugh. The following
20 ** explanation is from Lars:
21 ** The precondition that must be fulfilled is that DoMatch will consume
22 ** at least one character in text. This is true if *p is neither '*' nor
23 ** '\0'.) The last return has ABORT instead of FALSE to avoid quadratic
24 ** behaviour in cases like pattern "*a*b*c*d" with text "abcxxxxx". With
25 ** FALSE, each star-loop has to run to the end of the text; with ABORT
26 ** only the last one does.
28 ** Once the control of one instance of DoMatch enters the star-loop, that
29 ** instance will return either TRUE or ABORT, and any calling instance
30 ** will therefore return immediately after (without calling recursively
31 ** again). In effect, only one star-loop is ever active. It would be
32 ** possible to modify the code to maintain this context explicitly,
33 ** eliminating all recursive calls at the cost of some complication and
34 ** loss of clarity (and the ABORT stuff seems to be unclear enough by
35 ** itself). I think it would be unwise to try to get this into a
36 ** released version unless you have a good test data base to try it out
45 /* What character marks an inverted character class? */
46 #define NEGATE_CLASS '^'
47 /* Is "*" a common pattern? */
48 #define OPTIMIZE_JUST_STAR
49 /* Do tar(1) matching rules, which ignore a trailing slash? */
50 #undef MATCH_TAR_PATTERN
54 ** Match text and p, return TRUE, FALSE, or ABORT.
65 for ( ; *p; text++, p++) {
66 if (*text == '\0' && *p != '*')
70 /* Literal match with following character. */
82 /* Consecutive stars act just like one. */
85 /* Trailing star matches everything. */
88 if ((matched = DoMatch(text++, p)) != FALSE)
92 reverse = p[1] == NEGATE_CLASS ? TRUE : FALSE;
94 /* Inverted character class. */
96 for (last = 0400, matched = FALSE; *++p && *p != ']'; last = *p)
97 /* This next line requires a good C compiler. */
98 if (*p == '-' ? *text <= *++p && *text >= last : *text == *p)
100 if (matched == reverse)
106 #ifdef MATCH_TAR_PATTERN
109 #endif /* MATCH_TAR_ATTERN */
110 return *text == '\0';
115 ** User-level routine. Returns TRUE or FALSE.
122 #ifdef OPTIMIZE_JUST_STAR
123 if (p[0] == '*' && p[1] == '\0')
125 #endif /* OPTIMIZE_JUST_STAR */
126 return DoMatch(text, p) == TRUE;
134 /* Yes, we use gets not fgets. Sue me. */
143 printf("Wildmat tester. Enter pattern, then strings to test.\n");
144 printf("A blank line gets prompts for a new pattern; a blank pattern\n");
145 printf("exits the program.\n");
148 printf("\nEnter pattern: ");
149 (void)fflush(stdout);
150 if (gets(p) == NULL || p[0] == '\0')
153 printf("Enter text: ");
154 (void)fflush(stdout);
155 if (gets(text) == NULL)
158 /* Blank line; go back and get a new pattern. */
160 printf(" %s\n", wildmat(text, p) ? "YES" : "NO");