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regexec.c
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/* Extended regular expression matching and search library.
Copyright (C) 2002-2005, 2007, 2009, 2010 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Isamu Hasegawa <[email protected]>.
The GNU C 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 2.1 of the License, or (at your option) any later version.
The GNU C 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 the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
static reg_errcode_t match_ctx_init (re_match_context_t *cache, int eflags,
int n) internal_function;
static void match_ctx_clean (re_match_context_t *mctx) internal_function;
static void match_ctx_free (re_match_context_t *cache) internal_function;
static reg_errcode_t match_ctx_add_entry (re_match_context_t *cache, int node,
int str_idx, int from, int to)
internal_function;
static int search_cur_bkref_entry (const re_match_context_t *mctx, int str_idx)
internal_function;
static reg_errcode_t match_ctx_add_subtop (re_match_context_t *mctx, int node,
int str_idx) internal_function;
static re_sub_match_last_t * match_ctx_add_sublast (re_sub_match_top_t *subtop,
int node, int str_idx)
internal_function;
static void sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
re_dfastate_t **limited_sts, int last_node,
int last_str_idx)
internal_function;
static reg_errcode_t re_search_internal (const regex_t *preg,
const char *string, int length,
int start, int range, int stop,
size_t nmatch, regmatch_t pmatch[],
int eflags);
static int re_search_2_stub (struct re_pattern_buffer *bufp,
const char *string1, int length1,
const char *string2, int length2,
int start, int range, struct re_registers *regs,
int stop, int ret_len);
static int re_search_stub (struct re_pattern_buffer *bufp,
const char *string, int length, int start,
int range, int stop, struct re_registers *regs,
int ret_len);
static unsigned re_copy_regs (struct re_registers *regs, regmatch_t *pmatch,
int nregs, int regs_allocated);
static reg_errcode_t prune_impossible_nodes (re_match_context_t *mctx);
static int check_matching (re_match_context_t *mctx, int fl_longest_match,
int *p_match_first) internal_function;
static int check_halt_state_context (const re_match_context_t *mctx,
const re_dfastate_t *state, int idx)
internal_function;
static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
regmatch_t *prev_idx_match, int cur_node,
int cur_idx, int nmatch) internal_function;
static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
int str_idx, int dest_node, int nregs,
regmatch_t *regs,
re_node_set *eps_via_nodes)
internal_function;
static reg_errcode_t set_regs (const regex_t *preg,
const re_match_context_t *mctx,
size_t nmatch, regmatch_t *pmatch,
int fl_backtrack) internal_function;
static reg_errcode_t free_fail_stack_return (struct re_fail_stack_t *fs)
internal_function;
#ifdef RE_ENABLE_I18N
static int sift_states_iter_mb (const re_match_context_t *mctx,
re_sift_context_t *sctx,
int node_idx, int str_idx, int max_str_idx)
internal_function;
#endif /* RE_ENABLE_I18N */
static reg_errcode_t sift_states_backward (const re_match_context_t *mctx,
re_sift_context_t *sctx)
internal_function;
static reg_errcode_t build_sifted_states (const re_match_context_t *mctx,
re_sift_context_t *sctx, int str_idx,
re_node_set *cur_dest)
internal_function;
static reg_errcode_t update_cur_sifted_state (const re_match_context_t *mctx,
re_sift_context_t *sctx,
int str_idx,
re_node_set *dest_nodes)
internal_function;
static reg_errcode_t add_epsilon_src_nodes (const re_dfa_t *dfa,
re_node_set *dest_nodes,
const re_node_set *candidates)
internal_function;
static int check_dst_limits (const re_match_context_t *mctx,
re_node_set *limits,
int dst_node, int dst_idx, int src_node,
int src_idx) internal_function;
static int check_dst_limits_calc_pos_1 (const re_match_context_t *mctx,
int boundaries, int subexp_idx,
int from_node, int bkref_idx)
internal_function;
static int check_dst_limits_calc_pos (const re_match_context_t *mctx,
int limit, int subexp_idx,
int node, int str_idx,
int bkref_idx) internal_function;
static reg_errcode_t check_subexp_limits (const re_dfa_t *dfa,
re_node_set *dest_nodes,
const re_node_set *candidates,
re_node_set *limits,
struct re_backref_cache_entry *bkref_ents,
int str_idx) internal_function;
static reg_errcode_t sift_states_bkref (const re_match_context_t *mctx,
re_sift_context_t *sctx,
int str_idx, const re_node_set *candidates)
internal_function;
static reg_errcode_t merge_state_array (const re_dfa_t *dfa,
re_dfastate_t **dst,
re_dfastate_t **src, int num)
internal_function;
static re_dfastate_t *find_recover_state (reg_errcode_t *err,
re_match_context_t *mctx) internal_function;
static re_dfastate_t *transit_state (reg_errcode_t *err,
re_match_context_t *mctx,
re_dfastate_t *state) internal_function;
static re_dfastate_t *merge_state_with_log (reg_errcode_t *err,
re_match_context_t *mctx,
re_dfastate_t *next_state)
internal_function;
static reg_errcode_t check_subexp_matching_top (re_match_context_t *mctx,
re_node_set *cur_nodes,
int str_idx) internal_function;
#if 0
static re_dfastate_t *transit_state_sb (reg_errcode_t *err,
re_match_context_t *mctx,
re_dfastate_t *pstate)
internal_function;
#endif
#ifdef RE_ENABLE_I18N
static reg_errcode_t transit_state_mb (re_match_context_t *mctx,
re_dfastate_t *pstate)
internal_function;
#endif /* RE_ENABLE_I18N */
static reg_errcode_t transit_state_bkref (re_match_context_t *mctx,
const re_node_set *nodes)
internal_function;
static reg_errcode_t get_subexp (re_match_context_t *mctx,
int bkref_node, int bkref_str_idx)
internal_function;
static reg_errcode_t get_subexp_sub (re_match_context_t *mctx,
const re_sub_match_top_t *sub_top,
re_sub_match_last_t *sub_last,
int bkref_node, int bkref_str)
internal_function;
static int find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
int subexp_idx, int type) internal_function;
static reg_errcode_t check_arrival (re_match_context_t *mctx,
state_array_t *path, int top_node,
int top_str, int last_node, int last_str,
int type) internal_function;
static reg_errcode_t check_arrival_add_next_nodes (re_match_context_t *mctx,
int str_idx,
re_node_set *cur_nodes,
re_node_set *next_nodes)
internal_function;
static reg_errcode_t check_arrival_expand_ecl (const re_dfa_t *dfa,
re_node_set *cur_nodes,
int ex_subexp, int type)
internal_function;
static reg_errcode_t check_arrival_expand_ecl_sub (const re_dfa_t *dfa,
re_node_set *dst_nodes,
int target, int ex_subexp,
int type) internal_function;
static reg_errcode_t expand_bkref_cache (re_match_context_t *mctx,
re_node_set *cur_nodes, int cur_str,
int subexp_num, int type)
internal_function;
static int build_trtable (const re_dfa_t *dfa,
re_dfastate_t *state) internal_function;
#ifdef RE_ENABLE_I18N
static int check_node_accept_bytes (const re_dfa_t *dfa, int node_idx,
const re_string_t *input, int idx)
internal_function;
# ifdef _LIBC
static unsigned int find_collation_sequence_value (const unsigned char *mbs,
size_t name_len)
internal_function;
# endif /* _LIBC */
#endif /* RE_ENABLE_I18N */
static int group_nodes_into_DFAstates (const re_dfa_t *dfa,
const re_dfastate_t *state,
re_node_set *states_node,
bitset_t *states_ch) internal_function;
static int check_node_accept (const re_match_context_t *mctx,
const re_token_t *node, int idx)
internal_function;
static reg_errcode_t extend_buffers (re_match_context_t *mctx)
internal_function;
/* Entry point for POSIX code. */
/* regexec searches for a given pattern, specified by PREG, in the
string STRING.
If NMATCH is zero or REG_NOSUB was set in the cflags argument to
`regcomp', we ignore PMATCH. Otherwise, we assume PMATCH has at
least NMATCH elements, and we set them to the offsets of the
corresponding matched substrings.
EFLAGS specifies `execution flags' which affect matching: if
REG_NOTBOL is set, then ^ does not match at the beginning of the
string; if REG_NOTEOL is set, then $ does not match at the end.
We return 0 if we find a match and REG_NOMATCH if not. */
int
regexec (
const regex_t *__restrict preg,
const char *__restrict string,
size_t nmatch,
regmatch_t pmatch[],
int eflags)
{
reg_errcode_t err;
int start, length;
if (eflags & ~(REG_NOTBOL | REG_NOTEOL | REG_STARTEND))
return REG_BADPAT;
if (eflags & REG_STARTEND)
{
start = pmatch[0].rm_so;
length = pmatch[0].rm_eo;
}
else
{
start = 0;
length = strlen (string);
}
__libc_lock_lock (dfa->lock);
if (preg->no_sub)
err = re_search_internal (preg, string, length, start, length - start,
length, 0, NULL, eflags);
else
err = re_search_internal (preg, string, length, start, length - start,
length, nmatch, pmatch, eflags);
__libc_lock_unlock (dfa->lock);
return err != REG_NOERROR;
}
#ifdef _LIBC
# include <shlib-compat.h>
versioned_symbol (libc, __regexec, regexec, GLIBC_2_3_4);
# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4)
__typeof__ (__regexec) __compat_regexec;
int
attribute_compat_text_section
__compat_regexec (const regex_t *__restrict preg,
const char *__restrict string, size_t nmatch,
regmatch_t pmatch[], int eflags)
{
return regexec (preg, string, nmatch, pmatch,
eflags & (REG_NOTBOL | REG_NOTEOL));
}
compat_symbol (libc, __compat_regexec, regexec, GLIBC_2_0);
# endif
#endif
/* Entry points for GNU code. */
/* re_match, re_search, re_match_2, re_search_2
The former two functions operate on STRING with length LENGTH,
while the later two operate on concatenation of STRING1 and STRING2
with lengths LENGTH1 and LENGTH2, respectively.
re_match() matches the compiled pattern in BUFP against the string,
starting at index START.
re_search() first tries matching at index START, then it tries to match
starting from index START + 1, and so on. The last start position tried
is START + RANGE. (Thus RANGE = 0 forces re_search to operate the same
way as re_match().)
The parameter STOP of re_{match,search}_2 specifies that no match exceeding
the first STOP characters of the concatenation of the strings should be
concerned.
If REGS is not NULL, and BUFP->no_sub is not set, the offsets of the match
and all groups are stored in REGS. (For the "_2" variants, the offsets are
computed relative to the concatenation, not relative to the individual
strings.)
On success, re_match* functions return the length of the match, re_search*
return the position of the start of the match. Return value -1 means no
match was found and -2 indicates an internal error. */
int
re_match (struct re_pattern_buffer *bufp,
const char *string,
int length,
int start,
struct re_registers *regs)
{
return re_search_stub (bufp, string, length, start, 0, length, regs, 1);
}
#ifdef _LIBC
weak_alias (__re_match, re_match)
#endif
int
re_search (struct re_pattern_buffer *bufp,
const char *string,
int length, int start, int range,
struct re_registers *regs)
{
return re_search_stub (bufp, string, length, start, range, length, regs, 0);
}
#ifdef _LIBC
weak_alias (__re_search, re_search)
#endif
int
re_match_2 (struct re_pattern_buffer *bufp,
const char *string1, int length1,
const char *string2, int length2, int start,
struct re_registers *regs, int stop)
{
return re_search_2_stub (bufp, string1, length1, string2, length2,
start, 0, regs, stop, 1);
}
#ifdef _LIBC
weak_alias (__re_match_2, re_match_2)
#endif
int
re_search_2 (struct re_pattern_buffer *bufp,
const char *string1, int length1,
const char *string2, int length2, int start,
int range, struct re_registers *regs, int stop)
{
return re_search_2_stub (bufp, string1, length1, string2, length2,
start, range, regs, stop, 0);
}
#ifdef _LIBC
weak_alias (__re_search_2, re_search_2)
#endif
static int
re_search_2_stub (struct re_pattern_buffer *bufp,
const char *string1, int length1,
const char *string2, int length2, int start,
int range, struct re_registers *regs,
int stop, int ret_len)
{
const char *str;
int rval;
int len = length1 + length2;
int free_str = 0;
if (BE (length1 < 0 || length2 < 0 || stop < 0, 0))
return -2;
/* Concatenate the strings. */
if (length2 > 0)
if (length1 > 0)
{
char *s = re_malloc (char, len);
if (BE (s == NULL, 0))
return -2;
memcpy (s, string1, length1);
memcpy (s + length1, string2, length2);
str = s;
free_str = 1;
}
else
str = string2;
else
str = string1;
rval = re_search_stub (bufp, str, len, start, range, stop, regs, ret_len);
if (free_str)
re_free ((char *) str);
return rval;
}
/* The parameters have the same meaning as those of re_search.
Additional parameters:
If RET_LEN is nonzero the length of the match is returned (re_match style);
otherwise the position of the match is returned. */
static int
re_search_stub (struct re_pattern_buffer *bufp,
const char *string, int length, int start,
int range, int stop,
struct re_registers *regs, int ret_len)
{
reg_errcode_t result;
regmatch_t *pmatch;
int nregs, rval;
int eflags = 0;
/* Check for out-of-range. */
if (BE (start < 0 || start > length, 0))
return -1;
if (BE (start + range > length, 0))
range = length - start;
else if (BE (start + range < 0, 0))
range = -start;
__libc_lock_lock (dfa->lock);
eflags |= (bufp->not_bol) ? REG_NOTBOL : 0;
eflags |= (bufp->not_eol) ? REG_NOTEOL : 0;
/* Compile fastmap if we haven't yet. */
if (range > 0 && bufp->fastmap != NULL && !bufp->fastmap_accurate)
re_compile_fastmap (bufp);
if (BE (bufp->no_sub, 0))
regs = NULL;
/* We need at least 1 register. */
if (regs == NULL)
nregs = 1;
else if (BE (bufp->regs_allocated == REGS_FIXED &&
regs->num_regs < bufp->re_nsub + 1, 0))
{
nregs = regs->num_regs;
if (BE (nregs < 1, 0))
{
/* Nothing can be copied to regs. */
regs = NULL;
nregs = 1;
}
}
else
nregs = bufp->re_nsub + 1;
pmatch = re_malloc (regmatch_t, nregs);
if (BE (pmatch == NULL, 0))
{
rval = -2;
goto out;
}
result = re_search_internal (bufp, string, length, start, range, stop,
nregs, pmatch, eflags);
rval = 0;
/* I hope we needn't fill their regs with -1's when no match was found. */
if (result != REG_NOERROR)
rval = -1;
else if (regs != NULL)
{
/* If caller wants register contents data back, copy them. */
bufp->regs_allocated = re_copy_regs (regs, pmatch, nregs,
bufp->regs_allocated);
if (BE (bufp->regs_allocated == REGS_UNALLOCATED, 0))
rval = -2;
}
if (BE (rval == 0, 1))
{
if (ret_len)
{
assert (pmatch[0].rm_so == start);
rval = pmatch[0].rm_eo - start;
}
else
rval = pmatch[0].rm_so;
}
re_free (pmatch);
out:
__libc_lock_unlock (dfa->lock);
return rval;
}
static unsigned
re_copy_regs (struct re_registers *regs,
regmatch_t *pmatch,
int nregs, int regs_allocated)
{
int rval = REGS_REALLOCATE;
int i;
int need_regs = nregs + 1;
/* We need one extra element beyond `num_regs' for the `-1' marker GNU code
uses. */
/* Have the register data arrays been allocated? */
if (regs_allocated == REGS_UNALLOCATED)
{ /* No. So allocate them with malloc. */
regs->start = re_malloc (regoff_t, need_regs);
if (BE (regs->start == NULL, 0))
return REGS_UNALLOCATED;
regs->end = re_malloc (regoff_t, need_regs);
if (BE (regs->end == NULL, 0))
{
re_free (regs->start);
return REGS_UNALLOCATED;
}
regs->num_regs = need_regs;
}
else if (regs_allocated == REGS_REALLOCATE)
{ /* Yes. If we need more elements than were already
allocated, reallocate them. If we need fewer, just
leave it alone. */
if (BE (need_regs > regs->num_regs, 0))
{
regoff_t *new_start = re_realloc (regs->start, regoff_t, need_regs);
regoff_t *new_end;
if (BE (new_start == NULL, 0))
return REGS_UNALLOCATED;
new_end = re_realloc (regs->end, regoff_t, need_regs);
if (BE (new_end == NULL, 0))
{
re_free (new_start);
return REGS_UNALLOCATED;
}
regs->start = new_start;
regs->end = new_end;
regs->num_regs = need_regs;
}
}
else
{
assert (regs_allocated == REGS_FIXED);
/* This function may not be called with REGS_FIXED and nregs too big. */
assert (regs->num_regs >= nregs);
rval = REGS_FIXED;
}
/* Copy the regs. */
for (i = 0; i < nregs; ++i)
{
regs->start[i] = pmatch[i].rm_so;
regs->end[i] = pmatch[i].rm_eo;
}
for ( ; i < regs->num_regs; ++i)
regs->start[i] = regs->end[i] = -1;
return rval;
}
/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
ENDS. Subsequent matches using PATTERN_BUFFER and REGS will use
this memory for recording register information. STARTS and ENDS
must be allocated using the malloc library routine, and must each
be at least NUM_REGS * sizeof (regoff_t) bytes long.
If NUM_REGS == 0, then subsequent matches should allocate their own
register data.
Unless this function is called, the first search or match using
PATTERN_BUFFER will allocate its own register data, without
freeing the old data. */
void
re_set_registers (struct re_pattern_buffer *bufp,
struct re_registers *regs,
unsigned num_regs,
regoff_t *starts,
regoff_t *ends)
{
if (num_regs)
{
bufp->regs_allocated = REGS_REALLOCATE;
regs->num_regs = num_regs;
regs->start = starts;
regs->end = ends;
}
else
{
bufp->regs_allocated = REGS_UNALLOCATED;
regs->num_regs = 0;
regs->start = regs->end = (regoff_t *) 0;
}
}
#ifdef _LIBC
weak_alias (__re_set_registers, re_set_registers)
#endif
/* Entry points compatible with 4.2 BSD regex library. We don't define
them unless specifically requested. */
#if defined _REGEX_RE_COMP || defined _LIBC
int
# ifdef _LIBC
weak_function
# endif
re_exec (s)
const char *s;
{
return 0 == regexec (&re_comp_buf, s, 0, NULL, 0);
}
#endif /* _REGEX_RE_COMP */
/* Internal entry point. */
/* Searches for a compiled pattern PREG in the string STRING, whose
length is LENGTH. NMATCH, PMATCH, and EFLAGS have the same
mingings with regexec. START, and RANGE have the same meanings
with re_search.
Return REG_NOERROR if we find a match, and REG_NOMATCH if not,
otherwise return the error code.
Note: We assume front end functions already check ranges.
(START + RANGE >= 0 && START + RANGE <= LENGTH) */
static reg_errcode_t
re_search_internal (const regex_t *preg,
const char *string,
int length, int start, int range, int stop,
size_t nmatch, regmatch_t pmatch[],
int eflags)
{
reg_errcode_t err;
const re_dfa_t *dfa = (const re_dfa_t *) preg->buffer;
int left_lim, right_lim, incr;
int fl_longest_match, match_first, match_kind, match_last = -1;
int extra_nmatch;
int sb, ch;
#if defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
re_match_context_t mctx = { .dfa = dfa };
#else
re_match_context_t mctx;
#endif
char *fastmap = (preg->fastmap != NULL && preg->fastmap_accurate
&& range && !preg->can_be_null) ? preg->fastmap : NULL;
RE_TRANSLATE_TYPE t = preg->translate;
#if !(defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
memset (&mctx, '\0', sizeof (re_match_context_t));
mctx.dfa = dfa;
#endif
extra_nmatch = (nmatch > preg->re_nsub) ? nmatch - (preg->re_nsub + 1) : 0;
nmatch -= extra_nmatch;
/* Check if the DFA haven't been compiled. */
if (BE (preg->used == 0 || dfa->init_state == NULL
|| dfa->init_state_word == NULL || dfa->init_state_nl == NULL
|| dfa->init_state_begbuf == NULL, 0))
return REG_NOMATCH;
#ifdef DEBUG
/* We assume front-end functions already check them. */
assert (start + range >= 0 && start + range <= length);
#endif
/* If initial states with non-begbuf contexts have no elements,
the regex must be anchored. If preg->newline_anchor is set,
we'll never use init_state_nl, so do not check it. */
if (dfa->init_state->nodes.nelem == 0
&& dfa->init_state_word->nodes.nelem == 0
&& (dfa->init_state_nl->nodes.nelem == 0
|| !preg->newline_anchor))
{
if (start != 0 && start + range != 0)
return REG_NOMATCH;
start = range = 0;
}
/* We must check the longest matching, if nmatch > 0. */
fl_longest_match = (nmatch != 0 || dfa->nbackref);
err = re_string_allocate (&mctx.input, string, length, dfa->nodes_len + 1,
preg->translate, preg->syntax & RE_ICASE, dfa);
if (BE (err != REG_NOERROR, 0))
goto free_return;
mctx.input.stop = stop;
mctx.input.raw_stop = stop;
mctx.input.newline_anchor = preg->newline_anchor;
err = match_ctx_init (&mctx, eflags, dfa->nbackref * 2);
if (BE (err != REG_NOERROR, 0))
goto free_return;
/* We will log all the DFA states through which the dfa pass,
if nmatch > 1, or this dfa has "multibyte node", which is a
back-reference or a node which can accept multibyte character or
multi character collating element. */
if (nmatch > 1 || dfa->has_mb_node)
{
/* Avoid overflow. */
if (BE (SIZE_MAX / sizeof (re_dfastate_t *) <= mctx.input.bufs_len, 0))
{
err = REG_ESPACE;
goto free_return;
}
mctx.state_log = re_malloc (re_dfastate_t *, mctx.input.bufs_len + 1);
if (BE (mctx.state_log == NULL, 0))
{
err = REG_ESPACE;
goto free_return;
}
}
else
mctx.state_log = NULL;
match_first = start;
mctx.input.tip_context = (eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
: CONTEXT_NEWLINE | CONTEXT_BEGBUF;
/* Check incrementally whether of not the input string match. */
incr = (range < 0) ? -1 : 1;
left_lim = (range < 0) ? start + range : start;
right_lim = (range < 0) ? start : start + range;
sb = dfa->mb_cur_max == 1;
match_kind =
(fastmap
? ((sb || !(preg->syntax & RE_ICASE || t) ? 4 : 0)
| (range >= 0 ? 2 : 0)
| (t != NULL ? 1 : 0))
: 8);
for (;; match_first += incr)
{
err = REG_NOMATCH;
if (match_first < left_lim || right_lim < match_first)
goto free_return;
/* Advance as rapidly as possible through the string, until we
find a plausible place to start matching. This may be done
with varying efficiency, so there are various possibilities:
only the most common of them are specialized, in order to
save on code size. We use a switch statement for speed. */
switch (match_kind)
{
case 8:
/* No fastmap. */
break;
case 7:
/* Fastmap with single-byte translation, match forward. */
while (BE (match_first < right_lim, 1)
&& !fastmap[t[(unsigned char) string[match_first]]])
++match_first;
goto forward_match_found_start_or_reached_end;
case 6:
/* Fastmap without translation, match forward. */
while (BE (match_first < right_lim, 1)
&& !fastmap[(unsigned char) string[match_first]])
++match_first;
forward_match_found_start_or_reached_end:
if (BE (match_first == right_lim, 0))
{
ch = match_first >= length
? 0 : (unsigned char) string[match_first];
if (!fastmap[t ? t[ch] : ch])
goto free_return;
}
break;
case 4:
case 5:
/* Fastmap without multi-byte translation, match backwards. */
while (match_first >= left_lim)
{
ch = match_first >= length
? 0 : (unsigned char) string[match_first];
if (fastmap[t ? t[ch] : ch])
break;
--match_first;
}
if (match_first < left_lim)
goto free_return;
break;
default:
/* In this case, we can't determine easily the current byte,
since it might be a component byte of a multibyte
character. Then we use the constructed buffer instead. */
for (;;)
{
/* If MATCH_FIRST is out of the valid range, reconstruct the
buffers. */
unsigned int offset = match_first - mctx.input.raw_mbs_idx;
if (BE (offset >= (unsigned int) mctx.input.valid_raw_len, 0))
{
err = re_string_reconstruct (&mctx.input, match_first,
eflags);
if (BE (err != REG_NOERROR, 0))
goto free_return;
offset = match_first - mctx.input.raw_mbs_idx;
}
/* If MATCH_FIRST is out of the buffer, leave it as '\0'.
Note that MATCH_FIRST must not be smaller than 0. */
ch = (match_first >= length
? 0 : re_string_byte_at (&mctx.input, offset));
if (fastmap[ch])
break;
match_first += incr;
if (match_first < left_lim || match_first > right_lim)
{
err = REG_NOMATCH;
goto free_return;
}
}
break;
}
/* Reconstruct the buffers so that the matcher can assume that
the matching starts from the beginning of the buffer. */
err = re_string_reconstruct (&mctx.input, match_first, eflags);
if (BE (err != REG_NOERROR, 0))
goto free_return;
#ifdef RE_ENABLE_I18N
/* Don't consider this char as a possible match start if it part,
yet isn't the head, of a multibyte character. */
if (!sb && !re_string_first_byte (&mctx.input, 0))
continue;
#endif
/* It seems to be appropriate one, then use the matcher. */
/* We assume that the matching starts from 0. */
mctx.state_log_top = mctx.nbkref_ents = mctx.max_mb_elem_len = 0;
match_last = check_matching (&mctx, fl_longest_match,
range >= 0 ? &match_first : NULL);
if (match_last != -1)
{
if (BE (match_last == -2, 0))
{
err = REG_ESPACE;
goto free_return;
}
else
{
mctx.match_last = match_last;
if ((!preg->no_sub && nmatch > 1) || dfa->nbackref)
{
re_dfastate_t *pstate = mctx.state_log[match_last];
mctx.last_node = check_halt_state_context (&mctx, pstate,
match_last);
}
if ((!preg->no_sub && nmatch > 1 && dfa->has_plural_match)
|| dfa->nbackref)
{
err = prune_impossible_nodes (&mctx);
if (err == REG_NOERROR)
break;
if (BE (err != REG_NOMATCH, 0))
goto free_return;
match_last = -1;
}
else
break; /* We found a match. */
}
}
match_ctx_clean (&mctx);
}
#ifdef DEBUG
assert (match_last != -1);
assert (err == REG_NOERROR);
#endif
/* Set pmatch[] if we need. */
if (nmatch > 0)
{
int reg_idx;
/* Initialize registers. */
for (reg_idx = 1; reg_idx < nmatch; ++reg_idx)
pmatch[reg_idx].rm_so = pmatch[reg_idx].rm_eo = -1;
/* Set the points where matching start/end. */
pmatch[0].rm_so = 0;
pmatch[0].rm_eo = mctx.match_last;
if (!preg->no_sub && nmatch > 1)
{
err = set_regs (preg, &mctx, nmatch, pmatch,
dfa->has_plural_match && dfa->nbackref > 0);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
/* At last, add the offset to the each registers, since we slided
the buffers so that we could assume that the matching starts
from 0. */
for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
if (pmatch[reg_idx].rm_so != -1)
{
#ifdef RE_ENABLE_I18N
if (BE (mctx.input.offsets_needed != 0, 0))
{
pmatch[reg_idx].rm_so =
(pmatch[reg_idx].rm_so == mctx.input.valid_len
? mctx.input.valid_raw_len
: mctx.input.offsets[pmatch[reg_idx].rm_so]);
pmatch[reg_idx].rm_eo =
(pmatch[reg_idx].rm_eo == mctx.input.valid_len
? mctx.input.valid_raw_len
: mctx.input.offsets[pmatch[reg_idx].rm_eo]);
}
#else
assert (mctx.input.offsets_needed == 0);
#endif
pmatch[reg_idx].rm_so += match_first;
pmatch[reg_idx].rm_eo += match_first;
}
for (reg_idx = 0; reg_idx < extra_nmatch; ++reg_idx)
{
pmatch[nmatch + reg_idx].rm_so = -1;
pmatch[nmatch + reg_idx].rm_eo = -1;
}
if (dfa->subexp_map)
for (reg_idx = 0; reg_idx + 1 < nmatch; reg_idx++)
if (dfa->subexp_map[reg_idx] != reg_idx)
{
pmatch[reg_idx + 1].rm_so
= pmatch[dfa->subexp_map[reg_idx] + 1].rm_so;
pmatch[reg_idx + 1].rm_eo
= pmatch[dfa->subexp_map[reg_idx] + 1].rm_eo;
}
}
free_return:
re_free (mctx.state_log);
if (dfa->nbackref)
match_ctx_free (&mctx);
re_string_destruct (&mctx.input);
return err;
}
static reg_errcode_t
prune_impossible_nodes (re_match_context_t *mctx)
{
const re_dfa_t *const dfa = mctx->dfa;
int halt_node, match_last;
reg_errcode_t ret;
re_dfastate_t **sifted_states;
re_dfastate_t **lim_states = NULL;
re_sift_context_t sctx;
#ifdef DEBUG
assert (mctx->state_log != NULL);
#endif
match_last = mctx->match_last;
halt_node = mctx->last_node;
/* Avoid overflow. */
if (BE (SIZE_MAX / sizeof (re_dfastate_t *) <= match_last, 0))
return REG_ESPACE;
sifted_states = re_malloc (re_dfastate_t *, match_last + 1);
if (BE (sifted_states == NULL, 0))
{
ret = REG_ESPACE;
goto free_return;
}
if (dfa->nbackref)
{
lim_states = re_malloc (re_dfastate_t *, match_last + 1);
if (BE (lim_states == NULL, 0))
{
ret = REG_ESPACE;
goto free_return;
}
while (1)
{
memset (lim_states, '\0',
sizeof (re_dfastate_t *) * (match_last + 1));
sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
match_last);
ret = sift_states_backward (mctx, &sctx);
re_node_set_free (&sctx.limits);
if (BE (ret != REG_NOERROR, 0))
goto free_return;
if (sifted_states[0] != NULL || lim_states[0] != NULL)
break;
do
{
--match_last;
if (match_last < 0)
{
ret = REG_NOMATCH;
goto free_return;
}
} while (mctx->state_log[match_last] == NULL
|| !mctx->state_log[match_last]->halt);
halt_node = check_halt_state_context (mctx,
mctx->state_log[match_last],
match_last);
}
ret = merge_state_array (dfa, sifted_states, lim_states,
match_last + 1);
re_free (lim_states);