/****************************************************************************
* libs/libc/regex/regexec.c
*
* regexec.c - TRE POSIX compatible matching functions (and more).
*
* Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>
#include <limits.h>
#include <regex.h>
#include "tre.h"
#include <assert.h>
/****************************************************************************
* Private Functions
****************************************************************************/
static void tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
const tre_tnfa_t *tnfa, int *tags, int match_eo);
/* from tre-match-utils.h
*/
#define GET_NEXT_WCHAR() do { \
prev_c = next_c;pos += pos_add_next; \
if ((pos_add_next = mbtowc(&next_c, str_byte, MB_LEN_MAX)) <= 0){ \
if (pos_add_next < 0){ ret = REG_NOMATCH;goto error_exit; } \
else pos_add_next++; \
} \
str_byte += pos_add_next; \
} while (0)
#define IS_WORD_CHAR(c) ((c) == L'_' || tre_isalnum(c))
#define CHECK_ASSERTIONS(assertions) \
(((assertions & ASSERT_AT_BOL) \
&& (pos > 0 || reg_notbol) \
&& (prev_c != L'\n' || !reg_newline)) \
|| ((assertions & ASSERT_AT_EOL) \
&& (next_c != L'\0' || reg_noteol) \
&& (next_c != L'\n' || !reg_newline)) \
|| ((assertions & ASSERT_AT_BOW) \
&& (IS_WORD_CHAR(prev_c) || !IS_WORD_CHAR(next_c))) \
|| ((assertions & ASSERT_AT_EOW) \
&& (!IS_WORD_CHAR(prev_c) || IS_WORD_CHAR(next_c))) \
|| ((assertions & ASSERT_AT_WB) \
&& (pos != 0 && next_c != L'\0' \
&& IS_WORD_CHAR(prev_c) == IS_WORD_CHAR(next_c))) \
|| ((assertions & ASSERT_AT_WB_NEG) \
&& (pos == 0 || next_c == L'\0' \
|| IS_WORD_CHAR(prev_c) != IS_WORD_CHAR(next_c))))
#define CHECK_CHAR_CLASSES(trans_i, tnfa, eflags) \
(((trans_i->assertions & ASSERT_CHAR_CLASS) \
&& !(tnfa->cflags & REG_ICASE) \
&& !tre_isctype((tre_cint_t)prev_c, trans_i->u.class)) \
|| ((trans_i->assertions & ASSERT_CHAR_CLASS) \
&& (tnfa->cflags & REG_ICASE) \
&& !tre_isctype(tre_tolower((tre_cint_t)prev_c), trans_i->u.class) \
&& !tre_isctype(tre_toupper((tre_cint_t)prev_c), trans_i->u.class)) \
|| ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG) \
&& tre_neg_char_classes_match(trans_i->neg_classes, (tre_cint_t)prev_c, \
tnfa->cflags & REG_ICASE)))
/* Returns 1 if `t1' wins `t2', 0 otherwise. */
static int tre_tag_order(int num_tags, tre_tag_direction_t *tag_directions,
int *t1, int *t2)
{
int i;
for (i = 0; i < num_tags; i++)
{
if (tag_directions[i] == TRE_TAG_MINIMIZE)
{
if (t1[i] < t2[i])
{
return 1;
}
if (t1[i] > t2[i])
{
return 0;
}
}
else
{
if (t1[i] > t2[i])
{
return 1;
}
if (t1[i] < t2[i])
{
return 0;
}
}
}
/* assert(0); */
return 0;
}
static int tre_neg_char_classes_match(tre_ctype_t *classes, tre_cint_t wc,
int icase)
{
while (*classes != (tre_ctype_t)0)
{
if ((!icase &&
tre_isctype(wc,
*classes)) ||
(icase &&
(tre_isctype(tre_toupper(wc),
*classes) || tre_isctype(tre_tolower(wc),
*classes))))
{
return 1; /* Match. */
}
else
{
classes++;
}
}
return 0; /* No match. */
}
/* from tre-match-parallel.c
*/
/* This algorithm searches for matches basically by reading characters
* in the searched string one by one, starting at the beginning. All
* matching paths in the TNFA are traversed in parallel. When two or
* more paths reach the same state, exactly one is chosen according to
* tag ordering rules; if returning submatches is not required it does
* not matter which path is chosen.
*
* The worst case time required for finding the leftmost and longest
* match, or determining that there is no match, is always linearly
* dependent on the length of the text being searched.
*
* This algorithm cannot handle TNFAs with back referencing nodes.
* See `tre-match-backtrack.c'.
*/
typedef struct
{
tre_tnfa_transition_t *state;
int *tags;
} tre_tnfa_reach_t;
typedef struct
{
int pos;
int **tags;
} tre_reach_pos_t;
static reg_errcode_t tre_tnfa_run_parallel(const tre_tnfa_t *tnfa,
const void *string,
int *match_tags, int eflags,
int *match_end_ofs)
{
/* State variables required by GET_NEXT_WCHAR. */
tre_char_t prev_c = 0, next_c = 0;
const char *str_byte = string;
int pos = -1;
int pos_add_next = 1;
#ifdef TRE_MBSTATE
mbstate_t mbstate;
#endif /* TRE_MBSTATE */
int reg_notbol = eflags & REG_NOTBOL;
int reg_noteol = eflags & REG_NOTEOL;
int reg_newline = tnfa->cflags & REG_NEWLINE;
reg_errcode_t ret;
char *buf;
tre_tnfa_transition_t *trans_i;
tre_tnfa_reach_t *reach, *reach_next, *reach_i, *reach_next_i;
tre_reach_pos_t *reach_pos;
int *tag_i;
int num_tags;
int i;
int match_eo = -1; /* end offset of match (-1 if no
* match found yet) */
int new_match = 0;
int *tmp_tags = NULL;
int *tmp_iptr;
#ifdef TRE_MBSTATE
memset(&mbstate, '\0', sizeof(mbstate));
#endif /* TRE_MBSTATE */
if (!match_tags)
{
num_tags = 0;
}
else
{
num_tags = tnfa->num_tags;
}
/* Allocate memory for temporary data required for matching. This needs to
* be done for every matching operation to be thread safe. This allocates
* everything in a single large block from the stack frame using alloca()
* or with malloc() if alloca is unavailable.
*/
{
int tbytes;
int rbytes;
int pbytes;
int xbytes;
int total_bytes;
char *tmp_buf;
/* Compute the length of the block we need. */
tbytes = sizeof(*tmp_tags) * num_tags;
rbytes = sizeof(*reach_next) * (tnfa->num_states + 1);
pbytes = sizeof(*reach_pos) * tnfa->num_states;
xbytes = sizeof(int) * num_tags;
total_bytes = (sizeof(long) - 1) * 4 /* for alignment paddings */
+ (rbytes + xbytes * tnfa->num_states) * 2 + tbytes +
pbytes;
/* Allocate the memory. */
buf = xmalloc((unsigned)total_bytes);
if (buf == NULL)
{
return REG_ESPACE;
}
memset(buf, 0, (size_t)total_bytes);
/* Get the various pointers within tmp_buf (properly aligned). */
tmp_tags = (void *)buf;
tmp_buf = buf + tbytes;
tmp_buf += ALIGN(tmp_buf, long);
reach_next = (void *)tmp_buf;
tmp_buf += rbytes;
tmp_buf += ALIGN(tmp_buf, long);
reach = (void *)tmp_buf;
tmp_buf += rbytes;
tmp_buf += ALIGN(tmp_buf, long);
reach_pos = (void *)tmp_buf;
tmp_buf += pbytes;
tmp_buf += ALIGN(tmp_buf, long);
for (i = 0; i < tnfa->num_states; i++)
{
reach[i].tags = (void *)tmp_buf;
tmp_buf += xbytes;
reach_next[i].tags = (void *)tmp_buf;
tmp_buf += xbytes;
}
}
for (i = 0; i < tnfa->num_states; i++)
{
reach_pos[i].pos = -1;
}
GET_NEXT_WCHAR();
pos = 0;
reach_next_i = reach_next;
while (1)
{
/* If no match found yet, add the initial states to `reach_next'. */
if (match_eo < 0)
{
trans_i = tnfa->initial;
while (trans_i->state != NULL)
{
if (reach_pos[trans_i->state_id].pos < pos)
{
if (trans_i->assertions &&
CHECK_ASSERTIONS(trans_i->assertions))
{
trans_i++;
continue;
}
reach_next_i->state = trans_i->state;
for (i = 0; i < num_tags; i++)
{
reach_next_i->tags[i] = -1;
}
tag_i = trans_i->tags;
if (tag_i)
{
while (*tag_i >= 0)
{
if (*tag_i < num_tags)
{
reach_next_i->tags[*tag_i] = pos;
}
tag_i++;
}
}
if (reach_next_i->state == tnfa->final)
{
match_eo = pos;
new_match = 1;
for (i = 0; i < num_tags; i++)
{
match_tags[i] = reach_next_i->tags[i];
}
}
reach_pos[trans_i->state_id].pos = pos;
reach_pos[trans_i->state_id].tags = &reach_next_i->tags;
reach_next_i++;
}
trans_i++;
}
reach_next_i->state = NULL;
}
else
{
if (num_tags == 0 || reach_next_i == reach_next)
{
/* We have found a match. */
break;
}
}
/* Check for end of string. */
if (!next_c)
{
break;
}
GET_NEXT_WCHAR();
/* Swap `reach' and `reach_next'. */
reach_i = reach;
reach = reach_next;
reach_next = reach_i;
/* For each state in `reach', weed out states that don't fulfill the
* minimal matching conditions.
*/
if (tnfa->num_minimals && new_match)
{
new_match = 0;
reach_next_i = reach_next;
for (reach_i = reach; reach_i->state; reach_i++)
{
int skip = 0;
for (i = 0; tnfa->minimal_tags[i] >= 0; i += 2)
{
int end = tnfa->minimal_tags[i];
int start = tnfa->minimal_tags[i + 1];
if (end >= num_tags)
{
skip = 1;
break;
}
else if (reach_i->tags[start] == match_tags[start] &&
reach_i->tags[end] < match_tags[end])
{
skip = 1;
break;
}
}
if (!skip)
{
reach_next_i->state = reach_i->state;
tmp_iptr = reach_next_i->tags;
reach_next_i->tags = reach_i->tags;
reach_i->tags = tmp_iptr;
reach_next_i++;
}
}
reach_next_i->state = NULL;
/* Swap `reach' and `reach_next'. */
reach_i = reach;
reach = reach_next;
reach_next = reach_i;
}
/* For each state in `reach' see if there is a transition leaving with
* the current input symbol to a state not yet in `reach_next', and
* add the destination states to `reach_next'.
*/
reach_next_i = reach_next;
for (reach_i = reach; reach_i->state; reach_i++)
{
for (trans_i = reach_i->state; trans_i->state; trans_i++)
{
/* Does this transition match the input symbol? */
if (trans_i->code_min <= (tre_cint_t)prev_c &&
trans_i->code_max >= (tre_cint_t)prev_c)
{
if (trans_i->assertions &&
(CHECK_ASSERTIONS(trans_i->assertions) ||
CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
{
continue;
}
/* Compute the tags after this transition. */
for (i = 0; i < num_tags; i++)
{
tmp_tags[i] = reach_i->tags[i];
}
tag_i = trans_i->tags;
if (tag_i != NULL)
{
while (*tag_i >= 0)
{
if (*tag_i < num_tags)
{
tmp_tags[*tag_i] = pos;
}
tag_i++;
}
}
if (reach_pos[trans_i->state_id].pos < pos)
{
/* Found an unvisited node. */
reach_next_i->state = trans_i->state;
tmp_iptr = reach_next_i->tags;
reach_next_i->tags = tmp_tags;
tmp_tags = tmp_iptr;
reach_pos[trans_i->state_id].pos = pos;
reach_pos[trans_i->state_id].tags =
&reach_next_i->tags;
if (reach_next_i->state == tnfa->final &&
(match_eo == -1 ||
(num_tags > 0 &&
reach_next_i->tags[0] <= match_tags[0])))
{
match_eo = pos;
new_match = 1;
for (i = 0; i < num_tags; i++)
{
match_tags[i] = reach_next_i->tags[i];
}
}
reach_next_i++;
}
else
{
assert(reach_pos[trans_i->state_id].pos == pos);
/* Another path has also reached this state. We choose
* the winner by examining the tag values for both
* paths.
*/
if (tre_tag_order(num_tags, tnfa->tag_directions,
tmp_tags,
*reach_pos[trans_i->state_id].tags))
{
/* The new path wins. */
tmp_iptr =
*reach_pos[trans_i->state_id].tags;
*reach_pos[trans_i->state_id].tags = tmp_tags;
if (trans_i->state == tnfa->final)
{
match_eo = pos;
new_match = 1;
for (i = 0; i < num_tags; i++)
{
match_tags[i] = tmp_tags[i];
}
}
tmp_tags = tmp_iptr;
}
}
}
}
}
reach_next_i->state = NULL;
}
*match_end_ofs = match_eo;
ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
error_exit:
xfree(buf);
return ret;
}
/* from tre-match-backtrack.c
*/
/* This matcher is for regexps that use back referencing. Regexp matching
* with back referencing is an NP-complete problem on the number of back
* references. The easiest way to match them is to use a backtracking
* routine which basically goes through all possible paths in the TNFA
* and chooses the one which results in the best (leftmost and longest)
* match. This can be spectacularly expensive and may run out of stack
* space, but there really is no better known generic algorithm. Quoting
* Henry Spencer from comp.compilers:
* <URL: http://compilers.iecc.com/comparch/article/93-03-102>
*
* POSIX.2 REs require longest match, which is really exciting to
* implement since the obsolete ("basic") variant also includes
* \<digit>. I haven't found a better way of tackling this than doing
* a preliminary match using a DFA (or simulation) on a modified RE
* that just replicates subREs for \<digit>, and then doing a
* backtracking match to determine whether the subRE matches were
* right. This can be rather slow, but I console myself with the
* thought that people who use \<digit> deserve very slow execution.
* (Pun unintentional but very appropriate.)
*
*/
typedef struct
{
int pos;
const char *str_byte;
tre_tnfa_transition_t *state;
int state_id;
int next_c;
int *tags;
#ifdef TRE_MBSTATE
mbstate_t mbstate;
#endif /* TRE_MBSTATE */
} tre_backtrack_item_t;
struct tre_backtrack_struct
{
tre_backtrack_item_t item;
struct tre_backtrack_struct *prev;
struct tre_backtrack_struct *next;
};
typedef struct tre_backtrack_struct *tre_backtrack_t;
#ifdef TRE_MBSTATE
#define BT_STACK_MBSTATE_IN stack->item.mbstate = (mbstate)
#define BT_STACK_MBSTATE_OUT (mbstate) = stack->item.mbstate
#else /* !TRE_MBSTATE */
#define BT_STACK_MBSTATE_IN
#define BT_STACK_MBSTATE_OUT
#endif /* !TRE_MBSTATE */
#define tre_bt_mem_new tre_mem_new
#define tre_bt_mem_alloc tre_mem_alloc
#define tre_bt_mem_destroy tre_mem_destroy
#define BT_STACK_PUSH(_pos, _str_byte, _str_wide, _state, _state_id, _next_c, \
_tags, _mbstate) \
do \
{ \
int i; \
if (!stack->next) \
{ \
tre_backtrack_t s; \
s = tre_bt_mem_alloc(mem, sizeof(*s)); \
if (!s) \
{ \
tre_bt_mem_destroy(mem); \
if (tags) \
{ \
xfree (tags); \
} \
if (pmatch) \
{ \
xfree (pmatch); \
} \
if (states_seen) \
{ \
xfree (states_seen); \
} \
return REG_ESPACE; \
} \
s->prev = stack; \
s->next = NULL; \
s->item.tags = tre_bt_mem_alloc(mem, \
sizeof(*tags) * tnfa->num_tags); \
if (!s->item.tags) \
{ \
tre_bt_mem_destroy(mem); \
if (tags) \
{ \
xfree (tags); \
} \
if (pmatch) \
{ \
xfree (pmatch); \
} \
if (states_seen) \
{ \
xfree (states_seen); \
} \
return REG_ESPACE; \
} \
stack->next = s; \
stack = s; \
} \
else \
{ \
stack = stack->next; \
} \
stack->item.pos = (_pos); \
stack->item.str_byte = (_str_byte); \
stack->item.state = (_state); \
stack->item.state_id = (_state_id); \
stack->item.next_c = (_next_c); \
for (i = 0; i < tnfa->num_tags; i++) \
{ \
stack->item.tags[i] = (_tags)[i]; \
} \
BT_STACK_MBSTATE_IN; \
} \
while (0)
#define BT_STACK_POP() \
do \
{ \
int i; \
assert(stack->prev); \
pos = stack->item.pos; \
str_byte = stack->item.str_byte; \
state = stack->item.state; \
next_c = stack->item.next_c; \
for (i = 0; i < tnfa->num_tags; i++) \
{ \
tags[i] = stack->item.tags[i]; \
} \
BT_STACK_MBSTATE_OUT; \
stack = stack->prev; \
} \
while (0)
#undef MIN
#define MIN(a, b) ((a) <= (b) ? (a) : (b))
static reg_errcode_t tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa,
const void *string,
int *match_tags, int eflags,
int *match_end_ofs)
{
/* State variables required by GET_NEXT_WCHAR. */
tre_char_t prev_c = 0, next_c = 0;
const char *str_byte = string;
int pos = 0;
int pos_add_next = 1;
#ifdef TRE_MBSTATE
mbstate_t mbstate;
#endif /* TRE_MBSTATE */
int reg_notbol = eflags & REG_NOTBOL;
int reg_noteol = eflags & REG_NOTEOL;
int reg_newline = tnfa->cflags & REG_NEWLINE;
/* These are used to remember the necessary values of the above
* variables to return to the position where the current search
* started from.
*/
int next_c_start;
const char *str_byte_start;
int pos_start = -1;
#ifdef TRE_MBSTATE
mbstate_t mbstate_start;
#endif /* TRE_MBSTATE */
/* End offset of best match so far, or -1 if no match found yet. */
int match_eo = -1;
/* Tag arrays. */
int *next_tags;
int *tags = NULL;
/* Current TNFA state. */
tre_tnfa_transition_t *state;
int *states_seen = NULL;
/* Memory allocator to for allocating the backtracking stack. */
tre_mem_t mem = tre_bt_mem_new();
/* The backtracking stack. */
tre_backtrack_t stack;
tre_tnfa_transition_t *trans_i;
regmatch_t *pmatch = NULL;
int ret;
#ifdef TRE_MBSTATE
memset(&mbstate, '\0', sizeof(mbstate));
#endif /* TRE_MBSTATE */
if (!mem)
{
return REG_ESPACE;
}
stack = tre_bt_mem_alloc(mem, sizeof(*stack));
if (!stack)
{
ret = REG_ESPACE;
goto error_exit;
}
stack->prev = NULL;
stack->next = NULL;
if (tnfa->num_tags)
{
tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
if (!tags)
{
ret = REG_ESPACE;
goto error_exit;
}
}
if (tnfa->num_submatches)
{
pmatch = xmalloc(sizeof(*pmatch) * tnfa->num_submatches);
if (!pmatch)
{
ret = REG_ESPACE;
goto error_exit;
}
}
if (tnfa->num_states)
{
states_seen = xmalloc(sizeof(*states_seen) * tnfa->num_states);
if (!states_seen)
{
ret = REG_ESPACE;
goto error_exit;
}
}
retry:
{
int i;
for (i = 0; i < tnfa->num_tags; i++)
{
tags[i] = -1;
if (match_tags)
{
match_tags[i] = -1;
}
}
for (i = 0; i < tnfa->num_states; i++)
{
states_seen[i] = 0;
}
}
state = NULL;
pos = pos_start;
GET_NEXT_WCHAR();
pos_start = pos;
next_c_start = next_c;
str_byte_start = str_byte;
#ifdef TRE_MBSTATE
mbstate_start = mbstate;
#endif /* TRE_MBSTATE */
/* Handle initial states. */
next_tags = NULL;
for (trans_i = tnfa->initial; trans_i->state; trans_i++)
{
if (trans_i->assertions && CHECK_ASSERTIONS(trans_i->assertions))
{
continue;
}
if (state == NULL)
{
/* Start from this state. */
state = trans_i->state;
next_tags = trans_i->tags;
}
else
{
/* Backtrack to this state. */
BT_STACK_PUSH(pos, str_byte, 0, trans_i->state, trans_i->state_id,
next_c, tags, mbstate);
{
int *tmp = trans_i->tags;
if (tmp)
{
while (*tmp >= 0)
{
stack->item.tags[*tmp++] = pos;
}
}
}
}
}
if (next_tags)
{
for (; *next_tags >= 0; next_tags++)
{
tags[*next_tags] = pos;
}
}
if (state == NULL)
{
goto backtrack;
}
while (1)
{
tre_tnfa_transition_t *next_state;
int empty_br_match;
if (state == tnfa->final)
{
if (match_eo < pos ||
(match_eo == pos && match_tags &&
tre_tag_order(tnfa->num_tags, tnfa->tag_directions, tags,
match_tags)))
{
int i;
/* This match wins the previous match. */
match_eo = pos;
if (match_tags)
{
for (i = 0; i < tnfa->num_tags; i++)
{
match_tags[i] = tags[i];
}
}
}
/* Our TNFAs never have transitions leaving from the final state,
* so we jump right to backtracking.
*/
goto backtrack;
}
/* Go to the next character in the input string. */
empty_br_match = 0;
trans_i = state;
if (trans_i->state && trans_i->assertions & ASSERT_BACKREF)
{
/* This is a back reference state. All transitions leaving from
* this state have the same back reference "assertion". Instead
* of reading the next character, we match the back reference.
*/
int so;
int eo;
int bt = trans_i->u.backref;
int bt_len;
int result;
/* Get the substring we need to match against. Remember to
* turn off REG_NOSUB temporarily.
*/
tre_fill_pmatch(bt + 1, pmatch, tnfa->cflags & ~REG_NOSUB, tnfa,
tags, pos);
so = pmatch[bt].rm_so;
eo = pmatch[bt].rm_eo;
bt_len = eo - so;
result = strncmp((const char *) string + so, str_byte - 1,
(size_t) bt_len);
if (result == 0)
{
/* Back reference matched. Check for infinite loop. */
if (bt_len == 0)
{
empty_br_match = 1;
}
if (empty_br_match && states_seen[trans_i->state_id])
{
goto backtrack;
}
states_seen[trans_i->state_id] = empty_br_match;
/* Advance in input string and resync `prev_c', `next_c'
* and pos.
*/
str_byte += bt_len - 1;
pos += bt_len - 1;
GET_NEXT_WCHAR();
}
else
{
goto backtrack;
}
}
else
{
/* Check for end of string. */
if (next_c == L'\0')
{
goto backtrack;
}
/* Read the next character. */
GET_NEXT_WCHAR();
}
next_state = NULL;
for (trans_i = state; trans_i->state; trans_i++)
{
if (trans_i->code_min <= (tre_cint_t)prev_c &&
trans_i->code_max >= (tre_cint_t)prev_c)
{
if (trans_i->assertions &&
(CHECK_ASSERTIONS(trans_i->assertions) ||
CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
{
continue;
}
if (next_state == NULL)
{
/* First matching transition. */
next_state = trans_i->state;
next_tags = trans_i->tags;
}
else
{
/* Second matching transition. We may need to backtrack
* here
* to take this transition instead of the first one, so we
* push this transition in the backtracking stack so we can
* jump back here if needed.
*/
BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
trans_i->state_id, next_c, tags, mbstate);
{
int *tmp;
for (tmp = trans_i->tags; tmp && *tmp >= 0; tmp++)
{
stack->item.tags[*tmp] = pos;
}
}
#if 0
/* XXX - it's important not to look at all transitions here to keep
* the stack small!
*/
break;
#endif
}
}
}
if (next_state != NULL)
{
/* Matching transitions were found. Take the first one. */
state = next_state;
/* Update the tag values. */
if (next_tags)
{
while (*next_tags >= 0)
{
tags[*next_tags++] = pos;
}
}
}
else
{
backtrack:
/* A matching transition was not found. Try to backtrack. */
if (stack->prev)
{
if (stack->item.state->assertions & ASSERT_BACKREF)
{
states_seen[stack->item.state_id] = 0;
}
BT_STACK_POP();
}
else if (match_eo < 0)
{
/* Try starting from a later position in the input string.
* Check for end of string.
*/
if (next_c == L'\0')
{
break;
}
next_c = next_c_start;
#ifdef TRE_MBSTATE
mbstate = mbstate_start;
#endif /* TRE_MBSTATE */
str_byte = str_byte_start;
goto retry;
}
else
{
break;
}
}
}
ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
*match_end_ofs = match_eo;
error_exit:
tre_bt_mem_destroy(mem);
#ifndef TRE_USE_ALLOCA
if (tags)
{
xfree(tags);
}
if (pmatch)
{
xfree(pmatch);
}
if (states_seen)
{
xfree(states_seen);
}
#endif /* !TRE_USE_ALLOCA */
return ret;
}
/* from regexec.c
*/
/* Fills the POSIX.2 regmatch_t array according to the TNFA tag and match
* endpoint values.
*/
static void tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
const tre_tnfa_t *tnfa, int *tags, int match_eo)
{
tre_submatch_data_t *submatch_data;
unsigned int i;
unsigned int j;
int *parents;
i = 0;
if (match_eo >= 0 && !(cflags & REG_NOSUB))
{
/* Construct submatch offsets from the tags. */
submatch_data = tnfa->submatch_data;
while (i < tnfa->num_submatches && i < nmatch)
{
if (submatch_data[i].so_tag == tnfa->end_tag)
{
pmatch[i].rm_so = match_eo;
}
else
{
pmatch[i].rm_so = tags[submatch_data[i].so_tag];
}
if (submatch_data[i].eo_tag == tnfa->end_tag)
{
pmatch[i].rm_eo = match_eo;
}
else
{
pmatch[i].rm_eo = tags[submatch_data[i].eo_tag];
}
/* If either of the endpoints were not used, this submatch
* was not part of the match.
*/
if (pmatch[i].rm_so == -1 || pmatch[i].rm_eo == -1)
{
pmatch[i].rm_so = pmatch[i].rm_eo = -1;
}
i++;
}
/* Reset all submatches that are not within all of their parent
* submatches.
*/
i = 0;
while (i < tnfa->num_submatches && i < nmatch)
{
if (pmatch[i].rm_eo == -1)
{
assert(pmatch[i].rm_so == -1);
}
assert(pmatch[i].rm_so <= pmatch[i].rm_eo);
parents = submatch_data[i].parents;
if (parents != NULL)
{
for (j = 0; parents[j] >= 0; j++)
{
if (pmatch[i].rm_so < pmatch[parents[j]].rm_so ||
pmatch[i].rm_eo > pmatch[parents[j]].rm_eo)
{
pmatch[i].rm_so = pmatch[i].rm_eo = -1;
}
}
}
i++;
}
}
while (i < nmatch)
{
pmatch[i].rm_so = -1;
pmatch[i].rm_eo = -1;
i++;
}
}
/* Wrapper functions for POSIX compatible regexp matching.
*/
int regexec(const regex_t *restrict preg, const char *restrict string,
size_t nmatch, regmatch_t pmatch[restrict], int eflags)
{
tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
reg_errcode_t status;
int *tags = NULL;
int eo;
if (tnfa->cflags & REG_NOSUB)
{
nmatch = 0;
}
if (tnfa->num_tags > 0 && nmatch > 0)
{
tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
if (tags == NULL)
{
return REG_ESPACE;
}
}
/* Dispatch to the appropriate matcher. */
if (tnfa->have_backrefs)
{
/* The regex has back references, use the backtracking matcher. */
status = tre_tnfa_run_backtrack(tnfa, string, tags, eflags, &eo);
}
else
{
/* Exact matching, no back references, use the parallel matcher. */
status = tre_tnfa_run_parallel(tnfa, string, tags, eflags, &eo);
}
if (status == REG_OK)
{
/* A match was found, so fill the submatch registers. */
tre_fill_pmatch(nmatch, pmatch, tnfa->cflags, tnfa, tags, eo);
}
if (tags)
{
xfree(tags);
}
return status;
}