/*
 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: match.c,v 1.8 2001/03/02 19:57:08 ca Exp $")

#include <sm/string.h>

/*
**  SM_MATCH -- Match a character string against a glob pattern.
**
**      Parameters:
**              str -- string.
**              par -- pattern to find in str.
**
**      Returns:
**              true on match, false on non-match.
**
**  A pattern consists of normal characters, which match themselves,
**  and meta-sequences.  A * matches any sequence of characters.
**  A ? matches any single character.  A [ introduces a character class.
**  A ] marks the end of a character class; if the ] is missing then
**  the [ matches itself rather than introducing a character class.
**  A character class matches any of the characters between the brackets.
**  The range of characters from X to Y inclusive is written X-Y.
**  If the first character after the [ is ! then the character class is
**  complemented.
**
**  To include a ] in a character class, make it the first character
**  listed (after the !, if any).  To include a -, make it the first
**  character listed (after the !, if any) or the last character.
**  It is impossible for a ] to be the final character in a range.
**  For glob patterns that literally match "*", "?" or "[",
**  use [*], [?] or [[].
*/

bool
sm_match(str, pat)
        const char *str;
        const char *pat;
{
        bool ccnot, ccmatch, ccfirst;
        const char *ccstart;
        char c, c2;

        for (;;)
        {
                switch (*pat)
                {
                  case '\0':
                        return *str == '\0';
                  case '?':
                        if (*str == '\0')
                                return false;
                        ++pat;
                        ++str;
                        continue;
                  case '*':
                        ++pat;
                        if (*pat == '\0')
                        {
                                /* optimize case of trailing '*' */
                                return true;
                        }
                        for (;;)
                        {
                                if (sm_match(pat, str))
                                        return true;
                                if (*str == '\0')
                                        return false;
                                ++str;
                        }
                        /* NOTREACHED */
                  case '[':
                        ccstart = pat++;
                        ccnot = false;
                        if (*pat == '!')
                        {
                                ccnot = true;
                                ++pat;
                        }
                        ccmatch = false;
                        ccfirst = true;
                        for (;;)
                        {
                                if (*pat == '\0')
                                {
                                        pat = ccstart;
                                        goto defl;
                                }
                                if (*pat == ']' && !ccfirst)
                                        break;
                                c = *pat++;
                                ccfirst = false;
                                if (*pat == '-' && pat[1] != ']')
                                {
                                        ++pat;
                                        if (*pat == '\0')
                                        {
                                                pat = ccstart;
                                                goto defl;
                                        }
                                        c2 = *pat++;
                                        if (*str >= c && *str <= c2)
                                                ccmatch = true;
                                }
                                else
                                {
                                        if (*str == c)
                                                ccmatch = true;
                                }
                        }
                        if (ccmatch ^ ccnot)
                        {
                                ++pat;
                                ++str;
                        }
                        else
                                return false;
                        continue;
                default:
                defl:
                        if (*pat != *str)
                                return false;
                        ++pat;
                        ++str;
                        continue;
                }
        }
}