?? match.c
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/*
EPSHeader
File: match.c
Author: J. Kercheval
Created: Sat, 01/05/1991 22:21:49
*/
/*
EPSRevision History
J. Kercheval Wed, 02/20/1991 22:29:01 Released to Public Domain
J. Kercheval Fri, 02/22/1991 15:29:01 fix '\' bugs (two :( of them)
J. Kercheval Sun, 03/10/1991 19:31:29 add error return to matche()
J. Kercheval Sun, 03/10/1991 20:11:11 add is_valid_pattern code
J. Kercheval Sun, 03/10/1991 20:37:11 beef up main()
J. Kercheval Tue, 03/12/1991 22:25:10 Released as V1.1 to Public Domain
*/
/*
Wildcard Pattern Matching
*/
#include "match.h"
int matche_after_star (register char *pattern, register char *text);
int fast_match_after_star (register char *pattern, register char *text);
/*----------------------------------------------------------------------------
*
* Return TRUE if PATTERN has any special wildcard characters
*
----------------------------------------------------------------------------*/
BOOLEAN is_pattern (char *p)
{
while (*p)
{
switch (*p++)
{
case '?':
case '*':
case '[':
case '\\':
return TRUE;
}
}
return FALSE;
}
/*----------------------------------------------------------------------------
*
* Return TRUE if PATTERN has is a well formed regular expression according
* to the above syntax
*
* error_type is a return code based on the type of pattern error. Zero is
* returned in error_type if the pattern is a valid one. error_type return
* values are as follows:
*
* PATTERN_VALID - pattern is well formed
* PATTERN_ESC - pattern has invalid escape ('\' at end of pattern)
* PATTERN_RANGE - [..] construct has a no end range in a '-' pair (ie [a-])
* PATTERN_CLOSE - [..] construct has no end bracket (ie [abc-g )
* PATTERN_EMPTY - [..] construct is empty (ie [])
*
----------------------------------------------------------------------------*/
BOOLEAN is_valid_pattern (char *p, int *error_type)
{
/* init error_type */
*error_type = PATTERN_VALID;
/* loop through pattern to EOS */
while (*p)
{
/* determine pattern type */
switch (*p)
{
/* check literal escape, it cannot be at end of pattern */
case '\\':
if (!*++p)
{
*error_type = PATTERN_ESC;
return FALSE;
}
p++;
break;
/* the [..] construct must be well formed */
case '[':
p++;
/* if the next character is ']' then bad pattern */
if (*p == ']')
{
*error_type = PATTERN_EMPTY;
return FALSE;
}
/* if end of pattern here then bad pattern */
if (!*p)
{
*error_type = PATTERN_CLOSE;
return FALSE;
}
/* loop to end of [..] construct */
while (*p != ']')
{
/* check for literal escape */
if (*p == '\\')
{
p++;
/* if end of pattern here then bad pattern */
if (!*p++)
{
*error_type = PATTERN_ESC;
return FALSE;
}
}
else p++;
/* if end of pattern here then bad pattern */
if (!*p)
{
*error_type = PATTERN_CLOSE;
return FALSE;
}
/* if this a range */
if (*p == '-')
{
/* we must have an end of range */
if (!*++p || *p == ']')
{
*error_type = PATTERN_RANGE;
return FALSE;
}
else
{
/* check for literal escape */
if (*p == '\\')
p++;
/* if end of pattern here
then bad pattern */
if (!*p++)
{
*error_type = PATTERN_ESC;
return FALSE;
}
}
}
}
break;
/* all other characters are valid pattern elements */
case '*':
case '?':
default:
p++; /* "normal" character */
break;
}
}
return TRUE;
}
/*----------------------------------------------------------------------------
*
* Match the pattern PATTERN against the string TEXT;
*
* returns MATCH_VALID if pattern matches, or an errorcode as follows
* otherwise:
*
* MATCH_PATTERN - bad pattern
* MATCH_LITERAL - match failure on literal mismatch
* MATCH_RANGE - match failure on [..] construct
* MATCH_ABORT - premature end of text string
* MATCH_END - premature end of pattern string
* MATCH_VALID - valid match
*
*
* A match means the entire string TEXT is used up in matching.
*
* In the pattern string:
* `*' matches any sequence of characters (zero or more)
* `?' matches any character
* [SET] matches any character in the specified set,
* [!SET] or [^SET] matches any character not in the specified set.
*
* A set is composed of characters or ranges; a range looks like
* character hyphen character (as in 0-9 or A-Z). [0-9a-zA-Z_] is the
* minimal set of characters allowed in the [..] pattern construct.
* Other characters are allowed (ie. 8 bit characters) if your system
* will support them.
*
* To suppress the special syntactic significance of any of `[]*?!^-\',
* and match the character exactly, precede it with a `\'.
*
----------------------------------------------------------------------------*/
int matche (register char *p, register char *t)
{
register char range_start, range_end; /* start and end in range */
BOOLEAN invert; /* is this [..] or [!..] */
BOOLEAN member_match; /* have I matched the [..] construct? */
BOOLEAN loop; /* should I terminate? */
for ( ; *p; p++, t++)
{
/* if this is the end of the text
then this is the end of the match */
if (!*t)
{
return ( *p == '*' && *++p == '\0' ) ?
MATCH_VALID : MATCH_ABORT;
}
/* determine and react to pattern type */
switch (*p)
{
case '?': /* single any character match */
break;
case '*': /* multiple any character match */
return matche_after_star (p, t);
/* [..] construct, single member/exclusion character match */
case '[':
{
/* move to beginning of range */
p++;
/* check if this is a member match or exclusion match */
invert = FALSE;
if (*p == '!' || *p == '^')
{
invert = TRUE;
p++;
}
/* if closing bracket here or at range start then we have a
malformed pattern */
if (*p == ']')
{
return MATCH_PATTERN;
}
member_match = FALSE;
loop = TRUE;
while (loop)
{
/* if end of construct then loop is done */
if (*p == ']')
{
loop = FALSE;
continue;
}
/* matching a '!', '^', '-', '\' or a ']' */
if (*p == '\\')
{
range_start = range_end = *++p;
}
else range_start = range_end = *p;
/* if end of pattern then bad pattern (Missing ']') */
if (!*p)
return MATCH_PATTERN;
/* check for range bar */
if (*++p == '-')
{
/* get the range end */
range_end = *++p;
/* if end of pattern or construct
then bad pattern */
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