release/src/router/transmission/libtransmission/wildmat.c

   1 /* $XConsortium: wildmat.c,v 1.2 94/04/13 18:40:59 rws Exp $ */
   2 /*
   3 **
   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.
   7 **
   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.
  12 **
  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.
  27 **
  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
  37 **  on.
  38 */
  39
  40 #include "transmission.h"
  41 #include "utils.h"
  42
  43 #define ABORT -1
  44
  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
  51
  52
  53 /*
  54 **  Match text and p, return TRUE, FALSE, or ABORT.
  55 */
  56 static int
  57 DoMatch( const char * text, const char * p )
  58 {
  59     register int        last;
  60     register int        matched;
  61     register int        reverse;
  62
  63     for ( ; *p; text++, p++) {
  64         if (*text == '\0' && *p != '*')
  65             return ABORT;
  66         switch (*p) {
  67         case '\\':
  68             /* Literal match with following character. */
  69             p++;
  70             /* FALLTHROUGH */
  71         default:
  72             if (*text != *p)
  73                 return FALSE;
  74             continue;
  75         case '?':
  76             /* Match anything. */
  77             continue;
  78         case '*':
  79             while (*++p == '*')
  80                 /* Consecutive stars act just like one. */
  81                 continue;
  82             if (*p == '\0')
  83                 /* Trailing star matches everything. */
  84                 return TRUE;
  85             while (*text)
  86                 if ((matched = DoMatch(text++, p)) != FALSE)
  87                     return matched;
  88             return ABORT;
  89         case '[':
  90             reverse = p[1] == NEGATE_CLASS ? TRUE : FALSE;
  91             if (reverse)
  92                 /* Inverted character class. */
  93                 p++;
  94             for (last = 0400, matched = FALSE; *++p && *p != ']'; last = *p)
  95                 /* This next line requires a good C compiler. */
  96                 if (*p == '-' ? *text <= *++p && *text >= last : *text == *p)
  97                     matched = TRUE;
  98             if (matched == reverse)
  99                 return FALSE;
 100             continue;
 101         }
 102     }
 103
 104 #ifdef  MATCH_TAR_PATTERN
 105     if (*text == '/')
 106         return TRUE;
 107 #endif  /* MATCH_TAR_ATTERN */
 108     return *text == '\0';
 109 }
 110
 111
 112 /*
 113 **  User-level routine.  Returns TRUE or FALSE.
 114 */
 115 int
 116 tr_wildmat(const char * text, const char * p )
 117 {
 118     if (p[0] == '*' && p[1] == '\0')
 119         return TRUE;
 120
 121     return DoMatch(text, p) == TRUE;
 122 }