wildmat.c

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/* wildmat.h - NNTP wildmat processing functions
 *
 * Copyright (c) 1994-2008 Carnegie Mellon University.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Carnegie Mellon University
 *      Center for Technology Transfer and Enterprise Creation
 *      4615 Forbes Avenue
 *      Suite 302
 *      Pittsburgh, PA  15213
 *      (412) 268-7393, fax: (412) 268-7395
 *      innovation@andrew.cmu.edu
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * $Id: wildmat.c,v 1.4 2010/01/06 17:01:47 murch 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@osf.org>.
**  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 code, 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.
*/
#include <stdio.h>
#include <sys/types.h>
 
 
 
#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(const char *text, const char *p)
{
    int                 last;
    int                 matched;
    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++;
        matched = FALSE;
        if (p[1] == ']' || p[1] == '-')
        if (*++p == *text)
            matched = TRUE;
        for (last = *p; *++p && *p != ']'; last = *p)
        /* This next line requires a good C compiler. */
        if (*p == '-' && p[1] != ']'
            ? *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(const char *text, const char *p)
{
#ifdef  OPTIMIZE_JUST_STAR
    if (p[0] == '*' && p[1] == '\0')
    return TRUE;
#endif  /* OPTIMIZE_JUST_STAR */
    return DoMatch(text, p) == TRUE;
}