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regexec.c
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/* Extended regular expression matching and search library.
Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.
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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
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 void match_ctx_free_subtops (re_match_context_t *mctx)
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 (re_match_context_t *mctx, int str_idx)
internal_function;
static void match_ctx_clear_flag (re_match_context_t *mctx) 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, int check_subexp)
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) internal_function;
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) internal_function;
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) internal_function;
static unsigned re_copy_regs (struct re_registers *regs, regmatch_t *pmatch,
int nregs, int regs_allocated) internal_function;
static inline re_dfastate_t *acquire_init_state_context
(reg_errcode_t *err, const re_match_context_t *mctx, int idx)
__attribute ((always_inline)) internal_function;
static reg_errcode_t prune_impossible_nodes (re_match_context_t *mctx)
internal_function;
static int check_matching (re_match_context_t *mctx, int fl_longest_match,
int *p_match_first)
internal_function;
static int check_halt_node_context (const re_dfa_t *dfa, int node,
unsigned int context) 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 (re_dfa_t *dfa, regmatch_t *pmatch,
regmatch_t *prev_idx_match, int cur_node,
int cur_idx, int nmatch) internal_function;
static int proceed_next_node (const re_match_context_t *mctx,
int nregs, regmatch_t *regs,
int *pidx, int node, re_node_set *eps_via_nodes,
struct re_fail_stack_t *fs) internal_function;
static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
int str_idx, int *dests, int nregs,
regmatch_t *regs,
re_node_set *eps_via_nodes) internal_function;
static int pop_fail_stack (struct re_fail_stack_t *fs, int *pidx, 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 (re_match_context_t *mctx,
re_sift_context_t *sctx) internal_function;
static reg_errcode_t update_cur_sifted_state (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 (re_dfa_t *dfa,
re_node_set *dest_nodes,
const re_node_set *candidates) internal_function;
static reg_errcode_t sub_epsilon_src_nodes (re_dfa_t *dfa, int node,
re_node_set *dest_nodes,
const re_node_set *and_nodes) internal_function;
static int check_dst_limits (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 (re_match_context_t *mctx,
int limit, re_node_set *eclosures,
int subexp_idx, int node, int str_idx) internal_function;
static reg_errcode_t check_subexp_limits (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 (re_match_context_t *mctx,
re_sift_context_t *sctx,
int str_idx, re_node_set *dest_nodes) internal_function;
static reg_errcode_t clean_state_log_if_needed (re_match_context_t *mctx,
int next_state_log_idx) internal_function;
static reg_errcode_t merge_state_array (re_dfa_t *dfa, re_dfastate_t **dst,
re_dfastate_t **src, int num) internal_function;
static re_dfastate_t *transit_state (reg_errcode_t *err,
re_match_context_t *mctx,
re_dfastate_t *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 (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 (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 last_str, int subexp_num,
int type) internal_function;
static re_dfastate_t **build_trtable (re_dfa_t *dfa,
re_dfastate_t *state) internal_function;
#ifdef RE_ENABLE_I18N
static int check_node_accept_bytes (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 (re_dfa_t *dfa,
const re_dfastate_t *state,
re_node_set *states_node,
bitset *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 (preg, string, nmatch, pmatch, eflags)
const regex_t *__restrict preg;
const char *__restrict string;
size_t nmatch;
regmatch_t pmatch[];
int eflags;
{
reg_errcode_t err;
int length = strlen (string);
if (preg->no_sub)
err = re_search_internal (preg, string, length, 0, length, length, 0,
NULL, eflags);
else
err = re_search_internal (preg, string, length, 0, length, length, nmatch,
pmatch, eflags);
return err != REG_NOERROR;
}
#ifdef _LIBC
weak_alias (__regexec, regexec)
#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 is stroed 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 (bufp, string, length, start, regs)
struct re_pattern_buffer *bufp;
const char *string;
int length, 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 (bufp, string, length, start, range, regs)
struct re_pattern_buffer *bufp;
const char *string;
int length, start, 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 (bufp, string1, length1, string2, length2, start, regs, stop)
struct re_pattern_buffer *bufp;
const char *string1, *string2;
int length1, length2, start, stop;
struct re_registers *regs;
{
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 (bufp, string1, length1, string2, length2, start, range, regs, stop)
struct re_pattern_buffer *bufp;
const char *string1, *string2;
int length1, length2, start, range, stop;
struct re_registers *regs;
{
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 (bufp, string1, length1, string2, length2, start, range, regs,
stop, ret_len)
struct re_pattern_buffer *bufp;
const char *string1, *string2;
int length1, length2, start, range, stop, ret_len;
struct re_registers *regs;
{
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 (bufp, string, length, start, range, stop, regs, ret_len)
struct re_pattern_buffer *bufp;
const char *string;
int length, start, range, stop, ret_len;
struct re_registers *regs;
{
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;
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))
return -2;
result = re_search_internal (bufp, string, length, start, range, stop,
nregs, pmatch, eflags);
rval = 0;
/* I hope we needn't fill ther 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);
return rval;
}
static unsigned
re_copy_regs (regs, pmatch, nregs, regs_allocated)
struct re_registers *regs;
regmatch_t *pmatch;
int nregs, 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);
regs->end = re_malloc (regoff_t, need_regs);
if (BE (regs->start == NULL, 0) || BE (regs->end == NULL, 0))
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 = re_realloc (regs->end, regoff_t, need_regs);
if (BE (new_start == NULL, 0) || BE (new_end == NULL, 0))
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 (bufp, regs, num_regs, starts, ends)
struct re_pattern_buffer *bufp;
struct re_registers *regs;
unsigned num_regs;
regoff_t *starts, *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 */
static re_node_set empty_set;
/* 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 (preg, string, length, start, range, stop, nmatch, pmatch,
eflags)
const regex_t *preg;
const char *string;
int length, start, range, stop, eflags;
size_t nmatch;
regmatch_t pmatch[];
{
reg_errcode_t err;
re_dfa_t *dfa = (re_dfa_t *)preg->buffer;
int left_lim, right_lim, incr;
int fl_longest_match, match_first, match_last = -1;
int fast_translate, sb;
#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);
#if !(defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
memset (&mctx, '\0', sizeof (re_match_context_t));
mctx.dfa = dfa;
#endif
/* 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;
}
re_node_set_init_empty (&empty_set);
/* 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)
{
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;
fast_translate = sb || !(preg->syntax & RE_ICASE || preg->translate);
for (;;)
{
/* At first get the current byte from input string. */
if (fastmap)
{
if (BE (fast_translate, 1))
{
unsigned RE_TRANSLATE_TYPE t
= (unsigned RE_TRANSLATE_TYPE) preg->translate;
if (BE (range >= 0, 1))
{
if (BE (t != NULL, 0))
{
while (BE (match_first < right_lim, 1)
&& !fastmap[t[(unsigned char) string[match_first]]])
++match_first;
}
else
{
while (BE (match_first < right_lim, 1)
&& !fastmap[(unsigned char) string[match_first]])
++match_first;
}
if (BE (match_first == right_lim, 0))
{
int ch = match_first >= length
? 0 : (unsigned char) string[match_first];
if (!fastmap[t ? t[ch] : ch])
break;
}
}
else
{
while (match_first >= left_lim)
{
int ch = match_first >= length
? 0 : (unsigned char) string[match_first];
if (fastmap[t ? t[ch] : ch])
break;
--match_first;
}
if (match_first < left_lim)
break;
}
}
else
{
int ch;
do
{
/* 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. */
/* If MATCH_FIRST is out of the valid range, reconstruct the
buffers. */
if (mctx.input.raw_mbs_idx + mctx.input.valid_raw_len
<= match_first
|| match_first < mctx.input.raw_mbs_idx)
{
err = re_string_reconstruct (&mctx.input, match_first,
eflags);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
/* 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,
match_first
- mctx.input.raw_mbs_idx));
if (fastmap[ch])
break;
match_first += incr;
}
while (match_first >= left_lim && match_first <= right_lim);
if (! fastmap[ch])
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
/* Eliminate it when it is a component of a multibyte character
and isn't the head of a multibyte character. */
if (sb || re_string_first_byte (&mctx.input, 0))
#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);
}
/* Update counter. */
match_first += incr;
if (match_first < left_lim || right_lim < match_first)
break;
}
/* Set pmatch[] if we need. */
if (match_last != -1 && 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))
{
if (pmatch[reg_idx].rm_so == mctx.input.valid_len)
pmatch[reg_idx].rm_so += mctx.input.valid_raw_len - mctx.input.valid_len;
else
pmatch[reg_idx].rm_so = mctx.input.offsets[pmatch[reg_idx].rm_so];
if (pmatch[reg_idx].rm_eo == mctx.input.valid_len)
pmatch[reg_idx].rm_eo += mctx.input.valid_raw_len - mctx.input.valid_len;
else
pmatch[reg_idx].rm_eo = 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;
}
}
err = (match_last == -1) ? REG_NOMATCH : REG_NOERROR;
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 (mctx)
re_match_context_t *mctx;
{
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;
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));
match_ctx_clear_flag (mctx);
sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
match_last, 0);
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);
lim_states = NULL;
if (BE (ret != REG_NOERROR, 0))
goto free_return;
}
else
{
sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
match_last, 0);
ret = sift_states_backward (mctx, &sctx);
re_node_set_free (&sctx.limits);
if (BE (ret != REG_NOERROR, 0))
goto free_return;
}
re_free (mctx->state_log);
mctx->state_log = sifted_states;
sifted_states = NULL;
mctx->last_node = halt_node;
mctx->match_last = match_last;
ret = REG_NOERROR;
free_return:
re_free (sifted_states);
re_free (lim_states);
return ret;
}
/* Acquire an initial state and return it.
We must select appropriate initial state depending on the context,
since initial states may have constraints like "\<", "^", etc.. */
static inline re_dfastate_t *
acquire_init_state_context (err, mctx, idx)
reg_errcode_t *err;
const re_match_context_t *mctx;
int idx;
{
re_dfa_t *const dfa = mctx->dfa;
*err = REG_NOERROR;
if (dfa->init_state->has_constraint)
{
unsigned int context;
context = re_string_context_at (&mctx->input, idx - 1, mctx->eflags);
if (IS_WORD_CONTEXT (context))
return dfa->init_state_word;
else if (IS_ORDINARY_CONTEXT (context))
return dfa->init_state;
else if (IS_BEGBUF_CONTEXT (context) && IS_NEWLINE_CONTEXT (context))
return dfa->init_state_begbuf;
else if (IS_NEWLINE_CONTEXT (context))
return dfa->init_state_nl;
else if (IS_BEGBUF_CONTEXT (context))
{
/* It is relatively rare case, then calculate on demand. */
return re_acquire_state_context (err, dfa,
dfa->init_state->entrance_nodes,
context);
}
else
/* Must not happen? */
return dfa->init_state;
}
else
return dfa->init_state;
}
/* Check whether the regular expression match input string INPUT or not,
and return the index where the matching end, return -1 if not match,
or return -2 in case of an error.
FL_LONGEST_MATCH means we want the POSIX longest matching.
If P_MATCH_FIRST is not NULL, and the match fails, it is set to the
next place where we may want to try matching.
Note that the matcher assume that the maching starts from the current
index of the buffer. */
static int
check_matching (mctx, fl_longest_match, p_match_first)
re_match_context_t *mctx;
int fl_longest_match;
int *p_match_first;
{
re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err;
int match = 0;
int match_last = -1;
int cur_str_idx = re_string_cur_idx (&mctx->input);
re_dfastate_t *cur_state;
int at_init_state = p_match_first != NULL, skipped = 0;
cur_state = acquire_init_state_context (&err, mctx, cur_str_idx);
/* An initial state must not be NULL(invalid state). */
if (BE (cur_state == NULL, 0))
return -2;
if (mctx->state_log != NULL)
mctx->state_log[cur_str_idx] = cur_state;
/* Check OP_OPEN_SUBEXP in the initial state in case that we use them
later. E.g. Processing back references. */
if (BE (dfa->nbackref, 0))
{