gstreamer/subprojects/gst-plugins-good/gst/multifile/patternspec.c

334 lines
9.3 KiB
C

/* GPattern copy that supports raw (non-utf8) matching
* based on: GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997, 1999 Peter Mattis, Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "patternspec.h"
#include <string.h>
typedef enum
{
MATCH_ALL, /* "*A?A*" */
MATCH_ALL_TAIL, /* "*A?AA" */
MATCH_HEAD, /* "AAAA*" */
MATCH_TAIL, /* "*AAAA" */
MATCH_EXACT, /* "AAAAA" */
MATCH_LAST
} MatchType;
struct _PatternSpec
{
MatchMode match_mode;
MatchType match_type;
guint pattern_length;
guint min_length;
guint max_length;
gchar *pattern;
};
static inline gchar *
raw_strreverse (const gchar * str, gssize size)
{
g_assert (size > 0);
return g_strreverse (g_strndup (str, size));
}
static inline gboolean
pattern_ph_match (const gchar * match_pattern, MatchMode match_mode,
const gchar * match_string, gboolean * wildcard_reached_p)
{
register const gchar *pattern, *string;
register gchar ch;
pattern = match_pattern;
string = match_string;
ch = *pattern;
pattern++;
while (ch) {
switch (ch) {
case '?':
if (!*string)
return FALSE;
if (match_mode == MATCH_MODE_UTF8)
string = g_utf8_next_char (string);
else
++string;
break;
case '*':
*wildcard_reached_p = TRUE;
do {
ch = *pattern;
pattern++;
if (ch == '?') {
if (!*string)
return FALSE;
if (match_mode == MATCH_MODE_UTF8)
string = g_utf8_next_char (string);
else
++string;
}
}
while (ch == '*' || ch == '?');
if (!ch)
return TRUE;
do {
gboolean next_wildcard_reached = FALSE;
while (ch != *string) {
if (!*string)
return FALSE;
if (match_mode == MATCH_MODE_UTF8)
string = g_utf8_next_char (string);
else
++string;
}
string++;
if (pattern_ph_match (pattern, match_mode, string,
&next_wildcard_reached))
return TRUE;
if (next_wildcard_reached)
/* the forthcoming pattern substring up to the next wildcard has
* been matched, but a mismatch occurred for the rest of the
* pattern, following the next wildcard.
* there's no need to advance the current match position any
* further if the rest pattern will not match.
*/
return FALSE;
}
while (*string);
break;
default:
if (ch == *string)
string++;
else
return FALSE;
break;
}
ch = *pattern;
pattern++;
}
return *string == 0;
}
static gboolean
pattern_match (PatternSpec * pspec, guint string_length,
const gchar * string, const gchar * string_reversed)
{
MatchMode match_mode;
g_assert (pspec != NULL);
g_assert (string != NULL);
if (string_length < pspec->min_length || string_length > pspec->max_length)
return FALSE;
match_mode = pspec->match_mode;
if (match_mode == MATCH_MODE_AUTO) {
if (!g_utf8_validate (string, string_length, NULL))
match_mode = MATCH_MODE_RAW;
else
match_mode = MATCH_MODE_UTF8;
}
switch (pspec->match_type) {
gboolean dummy;
case MATCH_ALL:
return pattern_ph_match (pspec->pattern, match_mode, string, &dummy);
case MATCH_ALL_TAIL:
if (string_reversed)
return pattern_ph_match (pspec->pattern, match_mode, string_reversed,
&dummy);
else {
gboolean result;
gchar *tmp;
if (match_mode == MATCH_MODE_UTF8) {
tmp = g_utf8_strreverse (string, string_length);
} else {
tmp = raw_strreverse (string, string_length);
}
result = pattern_ph_match (pspec->pattern, match_mode, tmp, &dummy);
g_free (tmp);
return result;
}
case MATCH_HEAD:
if (pspec->pattern_length == string_length)
return memcmp (pspec->pattern, string, string_length) == 0;
else if (pspec->pattern_length)
return memcmp (pspec->pattern, string, pspec->pattern_length) == 0;
else
return TRUE;
case MATCH_TAIL:
if (pspec->pattern_length)
/* compare incl. NUL terminator */
return memcmp (pspec->pattern,
string + (string_length - pspec->pattern_length),
pspec->pattern_length + 1) == 0;
else
return TRUE;
case MATCH_EXACT:
if (pspec->pattern_length != string_length)
return FALSE;
else
return memcmp (pspec->pattern, string, string_length) == 0;
default:
g_return_val_if_fail (pspec->match_type < MATCH_LAST, FALSE);
return FALSE;
}
}
PatternSpec *
pattern_spec_new (const gchar * pattern, MatchMode match_mode)
{
PatternSpec *pspec;
gboolean seen_joker = FALSE, seen_wildcard = FALSE, more_wildcards = FALSE;
gint hw_pos = -1, tw_pos = -1, hj_pos = -1, tj_pos = -1;
gboolean follows_wildcard = FALSE;
guint pending_jokers = 0;
const gchar *s;
gchar *d;
guint i;
g_assert (pattern != NULL);
g_assert (match_mode != MATCH_MODE_UTF8
|| g_utf8_validate (pattern, -1, NULL));
/* canonicalize pattern and collect necessary stats */
pspec = g_new (PatternSpec, 1);
pspec->match_mode = match_mode;
pspec->pattern_length = strlen (pattern);
pspec->min_length = 0;
pspec->max_length = 0;
pspec->pattern = g_new (gchar, pspec->pattern_length + 1);
if (pspec->match_mode == MATCH_MODE_AUTO) {
if (!g_utf8_validate (pattern, -1, NULL))
pspec->match_mode = MATCH_MODE_RAW;
}
d = pspec->pattern;
for (i = 0, s = pattern; *s != 0; s++) {
switch (*s) {
case '*':
if (follows_wildcard) { /* compress multiple wildcards */
pspec->pattern_length--;
continue;
}
follows_wildcard = TRUE;
if (hw_pos < 0)
hw_pos = i;
tw_pos = i;
break;
case '?':
pending_jokers++;
pspec->min_length++;
if (pspec->match_mode == MATCH_MODE_RAW) {
pspec->max_length += 1;
} else {
pspec->max_length += 4; /* maximum UTF-8 character length */
}
continue;
default:
for (; pending_jokers; pending_jokers--, i++) {
*d++ = '?';
if (hj_pos < 0)
hj_pos = i;
tj_pos = i;
}
follows_wildcard = FALSE;
pspec->min_length++;
pspec->max_length++;
break;
}
*d++ = *s;
i++;
}
for (; pending_jokers; pending_jokers--) {
*d++ = '?';
if (hj_pos < 0)
hj_pos = i;
tj_pos = i;
}
*d++ = 0;
seen_joker = hj_pos >= 0;
seen_wildcard = hw_pos >= 0;
more_wildcards = seen_wildcard && hw_pos != tw_pos;
if (seen_wildcard)
pspec->max_length = G_MAXUINT;
/* special case sole head/tail wildcard or exact matches */
if (!seen_joker && !more_wildcards) {
if (pspec->pattern[0] == '*') {
pspec->match_type = MATCH_TAIL;
memmove (pspec->pattern, pspec->pattern + 1, --pspec->pattern_length);
pspec->pattern[pspec->pattern_length] = 0;
return pspec;
}
if (pspec->pattern_length > 0 &&
pspec->pattern[pspec->pattern_length - 1] == '*') {
pspec->match_type = MATCH_HEAD;
pspec->pattern[--pspec->pattern_length] = 0;
return pspec;
}
if (!seen_wildcard) {
pspec->match_type = MATCH_EXACT;
return pspec;
}
}
/* now just need to distinguish between head or tail match start */
tw_pos = pspec->pattern_length - 1 - tw_pos; /* last pos to tail distance */
tj_pos = pspec->pattern_length - 1 - tj_pos; /* last pos to tail distance */
if (seen_wildcard)
pspec->match_type = tw_pos > hw_pos ? MATCH_ALL_TAIL : MATCH_ALL;
else /* seen_joker */
pspec->match_type = tj_pos > hj_pos ? MATCH_ALL_TAIL : MATCH_ALL;
if (pspec->match_type == MATCH_ALL_TAIL) {
gchar *tmp = pspec->pattern;
if (pspec->match_mode == MATCH_MODE_RAW) {
pspec->pattern = raw_strreverse (pspec->pattern, pspec->pattern_length);
} else {
pspec->pattern =
g_utf8_strreverse (pspec->pattern, pspec->pattern_length);
}
g_free (tmp);
}
return pspec;
}
void
pattern_spec_free (PatternSpec * pspec)
{
g_assert (pspec != NULL);
g_free (pspec->pattern);
g_free (pspec);
}
gboolean
pattern_match_string (PatternSpec * pspec, const gchar * string)
{
return pattern_match (pspec, strlen (string), string, NULL);
}