--- /dev/null
+/* $XConsortium: wildmat.c,v 1.2 94/04/13 18:40:59 rws Exp $ */
+/*
+**
+** Do shell-style pattern matching for ?, \, [], and * characters.
+** Might not be robust in face of malformed patterns; e.g., "foo[a-"
+** could cause a segmentation violation. It is 8bit clean.
+**
+** Written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
+** Rich $alz is now <rsalz@bbn.com>.
+** April, 1991: Replaced mutually-recursive calls with in-line code
+** for the star character.
+**
+** Special thanks to Lars Mathiesen <thorinn@diku.dk> for the ABORT code.
+** This can greatly speed up failing wildcard patterns. For example:
+** pattern: -*-*-*-*-*-*-12-*-*-*-m-*-*-*
+** text 1: -adobe-courier-bold-o-normal--12-120-75-75-m-70-iso8859-1
+** text 2: -adobe-courier-bold-o-normal--12-120-75-75-X-70-iso8859-1
+** Text 1 matches with 51 calls, while text 2 fails with 54 calls. Without
+** the ABORT, then it takes 22310 calls to fail. Ugh. The following
+** explanation is from Lars:
+** The precondition that must be fulfilled is that DoMatch will consume
+** at least one character in text. This is true if *p is neither '*' nor
+** '\0'.) The last return has ABORT instead of FALSE to avoid quadratic
+** behaviour in cases like pattern "*a*b*c*d" with text "abcxxxxx". With
+** FALSE, each star-loop has to run to the end of the text; with ABORT
+** only the last one does.
+**
+** Once the control of one instance of DoMatch enters the star-loop, that
+** instance will return either TRUE or ABORT, and any calling instance
+** will therefore return immediately after (without calling recursively
+** again). In effect, only one star-loop is ever active. It would be
+** possible to modify the code to maintain this context explicitly,
+** eliminating all recursive calls at the cost of some complication and
+** loss of clarity (and the ABORT stuff seems to be unclear enough by
+** itself). I think it would be unwise to try to get this into a
+** released version unless you have a good test data base to try it out
+** on.
+*/
+
+#define TRUE 1
+#define FALSE 0
+#define ABORT -1
+
+
+ /* What character marks an inverted character class? */
+#define NEGATE_CLASS '^'
+ /* Is "*" a common pattern? */
+#define OPTIMIZE_JUST_STAR
+ /* Do tar(1) matching rules, which ignore a trailing slash? */
+#undef MATCH_TAR_PATTERN
+
+
+/*
+** Match text and p, return TRUE, FALSE, or ABORT.
+*/
+static int
+DoMatch(text, p)
+ register char *text;
+ register char *p;
+{
+ register int last;
+ register int matched;
+ register int reverse;
+
+ for ( ; *p; text++, p++) {
+ if (*text == '\0' && *p != '*')
+ return ABORT;
+ switch (*p) {
+ case '\\':
+ /* Literal match with following character. */
+ p++;
+ /* FALLTHROUGH */
+ default:
+ if (*text != *p)
+ return FALSE;
+ continue;
+ case '?':
+ /* Match anything. */
+ continue;
+ case '*':
+ while (*++p == '*')
+ /* Consecutive stars act just like one. */
+ continue;
+ if (*p == '\0')
+ /* Trailing star matches everything. */
+ return TRUE;
+ while (*text)
+ if ((matched = DoMatch(text++, p)) != FALSE)
+ return matched;
+ return ABORT;
+ case '[':
+ reverse = p[1] == NEGATE_CLASS ? TRUE : FALSE;
+ if (reverse)
+ /* Inverted character class. */
+ p++;
+ for (last = 0400, matched = FALSE; *++p && *p != ']'; last = *p)
+ /* This next line requires a good C compiler. */
+ if (*p == '-' ? *text <= *++p && *text >= last : *text == *p)
+ matched = TRUE;
+ if (matched == reverse)
+ return FALSE;
+ continue;
+ }
+ }
+
+#ifdef MATCH_TAR_PATTERN
+ if (*text == '/')
+ return TRUE;
+#endif /* MATCH_TAR_ATTERN */
+ return *text == '\0';
+}
+
+
+/*
+** User-level routine. Returns TRUE or FALSE.
+*/
+int
+wildmat(text, p)
+ char *text;
+ char *p;
+{
+#ifdef OPTIMIZE_JUST_STAR
+ if (p[0] == '*' && p[1] == '\0')
+ return TRUE;
+#endif /* OPTIMIZE_JUST_STAR */
+ return DoMatch(text, p) == TRUE;
+}
+
+\f
+
+#ifdef TEST
+#include <stdio.h>
+
+/* Yes, we use gets not fgets. Sue me. */
+extern char *gets();
+
+
+main()
+{
+ char p[80];
+ char text[80];
+
+ printf("Wildmat tester. Enter pattern, then strings to test.\n");
+ printf("A blank line gets prompts for a new pattern; a blank pattern\n");
+ printf("exits the program.\n");
+
+ for ( ; ; ) {
+ printf("\nEnter pattern: ");
+ (void)fflush(stdout);
+ if (gets(p) == NULL || p[0] == '\0')
+ break;
+ for ( ; ; ) {
+ printf("Enter text: ");
+ (void)fflush(stdout);
+ if (gets(text) == NULL)
+ exit(0);
+ if (text[0] == '\0')
+ /* Blank line; go back and get a new pattern. */
+ break;
+ printf(" %s\n", wildmat(text, p) ? "YES" : "NO");
+ }
+ }
+
+ exit(0);
+ /* NOTREACHED */
+}
+#endif /* TEST */
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