/*
**  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

#include "ansidecl.h"

 /* 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
DEFUN (DoMatch, (text, p),
       register CONST char *text AND
       register CONST 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
DEFUN (wildmat, (text, p),
       char *text AND
       char *p)
{
#ifdef	OPTIMIZE_JUST_STAR
  if (p[0] == '*' && p[1] == '\0')
    return TRUE;
#endif /* OPTIMIZE_JUST_STAR */
  return DoMatch (text, p) == TRUE;
}



#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 */