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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 <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, 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 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 (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);
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);
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)
{
ret = REG_NOMATCH;
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 *
__attribute ((always_inline)) internal_function
acquire_init_state_context (reg_errcode_t *err, const re_match_context_t *mctx,
int idx)
{
const re_dfa_t *const dfa = mctx->dfa;
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 matching starts from the current
index of the buffer. */
static int
internal_function
check_matching (re_match_context_t *mctx, int fl_longest_match,
int *p_match_first)
{
const 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;
int next_start_idx = cur_str_idx;
err = REG_NOERROR;
cur_state = acquire_init_state_context (&err, mctx, cur_str_idx);
/* An initial state must not be NULL (invalid). */
if (BE (cur_state == NULL, 0))
{
assert (err == REG_ESPACE);
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))
{
at_init_state = 0;
err = check_subexp_matching_top (mctx, &cur_state->nodes, 0);
if (BE (err != REG_NOERROR, 0))
return err;
if (cur_state->has_backref)
{
err = transit_state_bkref (mctx, &cur_state->nodes);
if (BE (err != REG_NOERROR, 0))
return err;
}
}
}
/* If the RE accepts NULL string. */
if (BE (cur_state->halt, 0))
{
if (!cur_state->has_constraint
|| check_halt_state_context (mctx, cur_state, cur_str_idx))
{
if (!fl_longest_match)
return cur_str_idx;
else
{
match_last = cur_str_idx;
match = 1;
}
}
}
while (!re_string_eoi (&mctx->input))
{
re_dfastate_t *old_state = cur_state;
int next_char_idx = re_string_cur_idx (&mctx->input) + 1;
if (BE (next_char_idx >= mctx->input.bufs_len, 0)
|| (BE (next_char_idx >= mctx->input.valid_len, 0)
&& mctx->input.valid_len < mctx->input.len))
{
err = extend_buffers (mctx);
if (BE (err != REG_NOERROR, 0))
{
assert (err == REG_ESPACE);
return -2;
}
}
cur_state = transit_state (&err, mctx, cur_state);
if (mctx->state_log != NULL)
cur_state = merge_state_with_log (&err, mctx, cur_state);
if (cur_state == NULL)
{
/* Reached the invalid state or an error. Try to recover a valid
state using the state log, if available and if we have not
already found a valid (even if not the longest) match. */
if (BE (err != REG_NOERROR, 0))
return -2;
if (mctx->state_log == NULL
|| (match && !fl_longest_match)
|| (cur_state = find_recover_state (&err, mctx)) == NULL)
break;
}
if (BE (at_init_state, 0))
{
if (old_state == cur_state)
next_start_idx = next_char_idx;
else
at_init_state = 0;
}
if (cur_state->halt)
{
/* Reached a halt state.
Check the halt state can satisfy the current context. */
if (!cur_state->has_constraint
|| check_halt_state_context (mctx, cur_state,
re_string_cur_idx (&mctx->input)))
{
/* We found an appropriate halt state. */
match_last = re_string_cur_idx (&mctx->input);
match = 1;
/* We found a match, do not modify match_first below. */
p_match_first = NULL;
if (!fl_longest_match)
break;
}
}
}
if (p_match_first)
*p_match_first += next_start_idx;
return match_last;
}
/* Check NODE match the current context. */
static int
internal_function
check_halt_node_context (const re_dfa_t *dfa, int node, unsigned int context)
{
re_token_type_t type = dfa->nodes[node].type;
unsigned int constraint = dfa->nodes[node].constraint;
if (type != END_OF_RE)
return 0;
if (!constraint)
return 1;
if (NOT_SATISFY_NEXT_CONSTRAINT (constraint, context))
return 0;
return 1;
}
/* Check the halt state STATE match the current context.
Return 0 if not match, if the node, STATE has, is a halt node and
match the context, return the node. */
static int
internal_function
check_halt_state_context (const re_match_context_t *mctx,
const re_dfastate_t *state, int idx)
{
int i;
unsigned int context;
#ifdef DEBUG
assert (state->halt);
#endif
context = re_string_context_at (&mctx->input, idx, mctx->eflags);
for (i = 0; i < state->nodes.nelem; ++i)
if (check_halt_node_context (mctx->dfa, state->nodes.elems[i], context))
return state->nodes.elems[i];
return 0;
}
/* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
corresponding to the DFA).
Return the destination node, and update EPS_VIA_NODES, return -1 in case
of errors. */
static int
internal_function
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)
{
const re_dfa_t *const dfa = mctx->dfa;
int i, err;
if (IS_EPSILON_NODE (dfa->nodes[node].type))
{
re_node_set *cur_nodes = &mctx->state_log[*pidx]->nodes;
re_node_set *edests = &dfa->edests[node];
int dest_node;
err = re_node_set_insert (eps_via_nodes, node);
if (BE (err < 0, 0))
return -2;
/* Pick up a valid destination, or return -1 if none is found. */
for (dest_node = -1, i = 0; i < edests->nelem; ++i)
{
int candidate = edests->elems[i];
if (!re_node_set_contains (cur_nodes, candidate))
continue;
if (dest_node == -1)
dest_node = candidate;
else
{
/* In order to avoid infinite loop like "(a*)*", return the second
epsilon-transition if the first was already considered. */
if (re_node_set_contains (eps_via_nodes, dest_node))
return candidate;
/* Otherwise, push the second epsilon-transition on the fail stack. */
else if (fs != NULL
&& push_fail_stack (fs, *pidx, candidate, nregs, regs,
eps_via_nodes))
return -2;
/* We know we are going to exit. */
break;
}
}
return dest_node;
}
else
{
int naccepted = 0;
re_token_type_t type = dfa->nodes[node].type;
#ifdef RE_ENABLE_I18N
if (dfa->nodes[node].accept_mb)
naccepted = check_node_accept_bytes (dfa, node, &mctx->input, *pidx);
else
#endif /* RE_ENABLE_I18N */
if (type == OP_BACK_REF)
{
int subexp_idx = dfa->nodes[node].opr.idx + 1;
naccepted = regs[subexp_idx].rm_eo - regs[subexp_idx].rm_so;
if (fs != NULL)
{
if (regs[subexp_idx].rm_so == -1 || regs[subexp_idx].rm_eo == -1)
return -1;
else if (naccepted)
{
char *buf = (char *) re_string_get_buffer (&mctx->input);
if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
naccepted) != 0)
return -1;
}
}
if (naccepted == 0)
{
int dest_node;
err = re_node_set_insert (eps_via_nodes, node);
if (BE (err < 0, 0))
return -2;
dest_node = dfa->edests[node].elems[0];
if (re_node_set_contains (&mctx->state_log[*pidx]->nodes,
dest_node))
return dest_node;
}
}
if (naccepted != 0
|| check_node_accept (mctx, dfa->nodes + node, *pidx))
{
int dest_node = dfa->nexts[node];
*pidx = (naccepted == 0) ? *pidx + 1 : *pidx + naccepted;
if (fs && (*pidx > mctx->match_last || mctx->state_log[*pidx] == NULL
|| !re_node_set_contains (&mctx->state_log[*pidx]->nodes,
dest_node)))
return -1;
re_node_set_empty (eps_via_nodes);
return dest_node;
}
}
return -1;
}
static reg_errcode_t
internal_function
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)
{
reg_errcode_t err;
int num = fs->num++;
if (fs->num == fs->alloc)
{
struct re_fail_stack_ent_t *new_array;
new_array = realloc (fs->stack, (sizeof (struct re_fail_stack_ent_t)
* fs->alloc * 2));
if (new_array == NULL)
return REG_ESPACE;
fs->alloc *= 2;
fs->stack = new_array;
}
fs->stack[num].idx = str_idx;
fs->stack[num].node = dest_node;
fs->stack[num].regs = re_malloc (regmatch_t, nregs);
if (fs->stack[num].regs == NULL)
return REG_ESPACE;
memcpy (fs->stack[num].regs, regs, sizeof (regmatch_t) * nregs);
err = re_node_set_init_copy (&fs->stack[num].eps_via_nodes, eps_via_nodes);
return err;
}
static int
internal_function
pop_fail_stack (struct re_fail_stack_t *fs, int *pidx, int nregs,
regmatch_t *regs, re_node_set *eps_via_nodes)
{
int num = --fs->num;
assert (num >= 0);
*pidx = fs->stack[num].idx;
memcpy (regs, fs->stack[num].regs, sizeof (regmatch_t) * nregs);
re_node_set_free (eps_via_nodes);
re_free (fs->stack[num].regs);
*eps_via_nodes = fs->stack[num].eps_via_nodes;
return fs->stack[num].node;
}
/* Set the positions where the subexpressions are starts/ends to registers
PMATCH.
Note: We assume that pmatch[0] is already set, and
pmatch[i].rm_so == pmatch[i].rm_eo == -1 for 0 < i < nmatch. */
static reg_errcode_t
internal_function
set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
regmatch_t *pmatch, int fl_backtrack)
{
const re_dfa_t *dfa = (const re_dfa_t *) preg->buffer;
int idx, cur_node;
re_node_set eps_via_nodes;
struct re_fail_stack_t *fs;
struct re_fail_stack_t fs_body = { 0, 2, NULL };
regmatch_t *prev_idx_match;
int prev_idx_match_malloced = 0;
#ifdef DEBUG
assert (nmatch > 1);
assert (mctx->state_log != NULL);
#endif
if (fl_backtrack)
{
fs = &fs_body;
fs->stack = re_malloc (struct re_fail_stack_ent_t, fs->alloc);
if (fs->stack == NULL)
return REG_ESPACE;
}
else
fs = NULL;
cur_node = dfa->init_node;
re_node_set_init_empty (&eps_via_nodes);
#ifdef HAVE_ALLOCA
if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
else
#endif
{
prev_idx_match = re_malloc (regmatch_t, nmatch);
if (prev_idx_match == NULL)
{
free_fail_stack_return (fs);
return REG_ESPACE;
}
prev_idx_match_malloced = 1;
}
memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
{
update_regs (dfa, pmatch, prev_idx_match, cur_node, idx, nmatch);
if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
{
int reg_idx;
if (fs)
{
for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
if (pmatch[reg_idx].rm_so > -1 && pmatch[reg_idx].rm_eo == -1)
break;
if (reg_idx == nmatch)
{
re_node_set_free (&eps_via_nodes);
if (prev_idx_match_malloced)
re_free (prev_idx_match);
return free_fail_stack_return (fs);
}
cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
&eps_via_nodes);
}
else
{
re_node_set_free (&eps_via_nodes);
if (prev_idx_match_malloced)
re_free (prev_idx_match);
return REG_NOERROR;
}
}
/* Proceed to next node. */
cur_node = proceed_next_node (mctx, nmatch, pmatch, &idx, cur_node,
&eps_via_nodes, fs);
if (BE (cur_node < 0, 0))
{
if (BE (cur_node == -2, 0))
{
re_node_set_free (&eps_via_nodes);
if (prev_idx_match_malloced)
re_free (prev_idx_match);
free_fail_stack_return (fs);
return REG_ESPACE;
}
if (fs)
cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
&eps_via_nodes);
else
{
re_node_set_free (&eps_via_nodes);
if (prev_idx_match_malloced)
re_free (prev_idx_match);
return REG_NOMATCH;
}
}
}
re_node_set_free (&eps_via_nodes);
if (prev_idx_match_malloced)
re_free (prev_idx_match);
return free_fail_stack_return (fs);
}
static reg_errcode_t
internal_function
free_fail_stack_return (struct re_fail_stack_t *fs)
{
if (fs)
{
int fs_idx;
for (fs_idx = 0; fs_idx < fs->num; ++fs_idx)
{
re_node_set_free (&fs->stack[fs_idx].eps_via_nodes);
re_free (fs->stack[fs_idx].regs);
}
re_free (fs->stack);
}
return REG_NOERROR;
}
static void
internal_function
update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
regmatch_t *prev_idx_match, int cur_node, int cur_idx, int nmatch)
{
int type = dfa->nodes[cur_node].type;
if (type == OP_OPEN_SUBEXP)
{
int reg_num = dfa->nodes[cur_node].opr.idx + 1;
/* We are at the first node of this sub expression. */
if (reg_num < nmatch)
{
pmatch[reg_num].rm_so = cur_idx;
pmatch[reg_num].rm_eo = -1;
}
}
else if (type == OP_CLOSE_SUBEXP)
{
int reg_num = dfa->nodes[cur_node].opr.idx + 1;
if (reg_num < nmatch)
{
/* We are at the last node of this sub expression. */
if (pmatch[reg_num].rm_so < cur_idx)
{
pmatch[reg_num].rm_eo = cur_idx;
/* This is a non-empty match or we are not inside an optional
subexpression. Accept this right away. */
memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
}
else
{
if (dfa->nodes[cur_node].opt_subexp
&& prev_idx_match[reg_num].rm_so != -1)
/* We transited through an empty match for an optional
subexpression, like (a?)*, and this is not the subexp's
first match. Copy back the old content of the registers
so that matches of an inner subexpression are undone as
well, like in ((a?))*. */
memcpy (pmatch, prev_idx_match, sizeof (regmatch_t) * nmatch);
else
/* We completed a subexpression, but it may be part of
an optional one, so do not update PREV_IDX_MATCH. */
pmatch[reg_num].rm_eo = cur_idx;
}
}
}
}
/* This function checks the STATE_LOG from the SCTX->last_str_idx to 0
and sift the nodes in each states according to the following rules.
Updated state_log will be wrote to STATE_LOG.
Rules: We throw away the Node `a' in the STATE_LOG[STR_IDX] if...
1. When STR_IDX == MATCH_LAST(the last index in the state_log):
If `a' isn't the LAST_NODE and `a' can't epsilon transit to
the LAST_NODE, we throw away the node `a'.
2. When 0 <= STR_IDX < MATCH_LAST and `a' accepts
string `s' and transit to `b':
i. If 'b' isn't in the STATE_LOG[STR_IDX+strlen('s')], we throw
away the node `a'.
ii. If 'b' is in the STATE_LOG[STR_IDX+strlen('s')] but 'b' is
thrown away, we throw away the node `a'.
3. When 0 <= STR_IDX < MATCH_LAST and 'a' epsilon transit to 'b':
i. If 'b' isn't in the STATE_LOG[STR_IDX], we throw away the
node `a'.
ii. If 'b' is in the STATE_LOG[STR_IDX] but 'b' is thrown away,
we throw away the node `a'. */
#define STATE_NODE_CONTAINS(state,node) \
((state) != NULL && re_node_set_contains (&(state)->nodes, node))
static reg_errcode_t
internal_function
sift_states_backward (const re_match_context_t *mctx, re_sift_context_t *sctx)
{
reg_errcode_t err;
int null_cnt = 0;
int str_idx = sctx->last_str_idx;
re_node_set cur_dest;
#ifdef DEBUG
assert (mctx->state_log != NULL && mctx->state_log[str_idx] != NULL);
#endif
/* Build sifted state_log[str_idx]. It has the nodes which can epsilon
transit to the last_node and the last_node itself. */
err = re_node_set_init_1 (&cur_dest, sctx->last_node);
if (BE (err != REG_NOERROR, 0))
return err;
err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
if (BE (err != REG_NOERROR, 0))
goto free_return;
/* Then check each states in the state_log. */
while (str_idx > 0)
{
/* Update counters. */
null_cnt = (sctx->sifted_states[str_idx] == NULL) ? null_cnt + 1 : 0;
if (null_cnt > mctx->max_mb_elem_len)
{
memset (sctx->sifted_states, '\0',
sizeof (re_dfastate_t *) * str_idx);
re_node_set_free (&cur_dest);
return REG_NOERROR;
}
re_node_set_empty (&cur_dest);
--str_idx;
if (mctx->state_log[str_idx])
{
err = build_sifted_states (mctx, sctx, str_idx, &cur_dest);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
/* Add all the nodes which satisfy the following conditions:
- It can epsilon transit to a node in CUR_DEST.
- It is in CUR_SRC.
And update state_log. */
err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
err = REG_NOERROR;
free_return:
re_node_set_free (&cur_dest);
return err;
}
static reg_errcode_t
internal_function
build_sifted_states (const re_match_context_t *mctx, re_sift_context_t *sctx,
int str_idx, re_node_set *cur_dest)
{
const re_dfa_t *const dfa = mctx->dfa;
const re_node_set *cur_src = &mctx->state_log[str_idx]->non_eps_nodes;
int i;
/* Then build the next sifted state.
We build the next sifted state on `cur_dest', and update
`sifted_states[str_idx]' with `cur_dest'.
Note:
`cur_dest' is the sifted state from `state_log[str_idx + 1]'.
`cur_src' points the node_set of the old `state_log[str_idx]'
(with the epsilon nodes pre-filtered out). */
for (i = 0; i < cur_src->nelem; i++)
{
int prev_node = cur_src->elems[i];
int naccepted = 0;
int ret;
#ifdef DEBUG
re_token_type_t type = dfa->nodes[prev_node].type;
assert (!IS_EPSILON_NODE (type));
#endif
#ifdef RE_ENABLE_I18N
/* If the node may accept `multi byte'. */
if (dfa->nodes[prev_node].accept_mb)
naccepted = sift_states_iter_mb (mctx, sctx, prev_node,
str_idx, sctx->last_str_idx);
#endif /* RE_ENABLE_I18N */
/* We don't check backreferences here.
See update_cur_sifted_state(). */
if (!naccepted
&& check_node_accept (mctx, dfa->nodes + prev_node, str_idx)
&& STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + 1],
dfa->nexts[prev_node]))
naccepted = 1;
if (naccepted == 0)
continue;
if (sctx->limits.nelem)
{
int to_idx = str_idx + naccepted;
if (check_dst_limits (mctx, &sctx->limits,
dfa->nexts[prev_node], to_idx,
prev_node, str_idx))
continue;
}
ret = re_node_set_insert (cur_dest, prev_node);
if (BE (ret == -1, 0))
return REG_ESPACE;
}
return REG_NOERROR;
}
/* Helper functions. */
static reg_errcode_t
internal_function
clean_state_log_if_needed (re_match_context_t *mctx, int next_state_log_idx)
{
int top = mctx->state_log_top;
if (next_state_log_idx >= mctx->input.bufs_len
|| (next_state_log_idx >= mctx->input.valid_len
&& mctx->input.valid_len < mctx->input.len))
{
reg_errcode_t err;
err = extend_buffers (mctx);
if (BE (err != REG_NOERROR, 0))
return err;
}
if (top < next_state_log_idx)
{
memset (mctx->state_log + top + 1, '\0',
sizeof (re_dfastate_t *) * (next_state_log_idx - top));
mctx->state_log_top = next_state_log_idx;
}
return REG_NOERROR;
}
static reg_errcode_t
internal_function
merge_state_array (const re_dfa_t *dfa, re_dfastate_t **dst,
re_dfastate_t **src, int num)
{
int st_idx;
reg_errcode_t err;
for (st_idx = 0; st_idx < num; ++st_idx)
{
if (dst[st_idx] == NULL)
dst[st_idx] = src[st_idx];
else if (src[st_idx] != NULL)
{
re_node_set merged_set;
err = re_node_set_init_union (&merged_set, &dst[st_idx]->nodes,
&src[st_idx]->nodes);
if (BE (err != REG_NOERROR, 0))
return err;
dst[st_idx] = re_acquire_state (&err, dfa, &merged_set);
re_node_set_free (&merged_set);
if (BE (err != REG_NOERROR, 0))
return err;
}
}
return REG_NOERROR;
}
static reg_errcode_t
internal_function
update_cur_sifted_state (const re_match_context_t *mctx,
re_sift_context_t *sctx, int str_idx,
re_node_set *dest_nodes)
{
const re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err = REG_NOERROR;
const re_node_set *candidates;
candidates = ((mctx->state_log[str_idx] == NULL) ? NULL
: &mctx->state_log[str_idx]->nodes);
if (dest_nodes->nelem == 0)
sctx->sifted_states[str_idx] = NULL;
else
{
if (candidates)
{
/* At first, add the nodes which can epsilon transit to a node in
DEST_NODE. */
err = add_epsilon_src_nodes (dfa, dest_nodes, candidates);
if (BE (err != REG_NOERROR, 0))
return err;
/* Then, check the limitations in the current sift_context. */
if (sctx->limits.nelem)
{
err = check_subexp_limits (dfa, dest_nodes, candidates, &sctx->limits,
mctx->bkref_ents, str_idx);
if (BE (err != REG_NOERROR, 0))
return err;
}
}
sctx->sifted_states[str_idx] = re_acquire_state (&err, dfa, dest_nodes);
if (BE (err != REG_NOERROR, 0))
return err;
}
if (candidates && mctx->state_log[str_idx]->has_backref)
{
err = sift_states_bkref (mctx, sctx, str_idx, candidates);
if (BE (err != REG_NOERROR, 0))
return err;
}
return REG_NOERROR;
}
static reg_errcode_t
internal_function
add_epsilon_src_nodes (const re_dfa_t *dfa, re_node_set *dest_nodes,
const re_node_set *candidates)
{
reg_errcode_t err = REG_NOERROR;
int i;
re_dfastate_t *state = re_acquire_state (&err, dfa, dest_nodes);
if (BE (err != REG_NOERROR, 0))
return err;
if (!state->inveclosure.alloc)
{
err = re_node_set_alloc (&state->inveclosure, dest_nodes->nelem);
if (BE (err != REG_NOERROR, 0))
return REG_ESPACE;
for (i = 0; i < dest_nodes->nelem; i++)
{
err = re_node_set_merge (&state->inveclosure,
dfa->inveclosures + dest_nodes->elems[i]);
if (BE (err != REG_NOERROR, 0))
return REG_ESPACE;
}
}
return re_node_set_add_intersect (dest_nodes, candidates,
&state->inveclosure);
}
static reg_errcode_t
internal_function
sub_epsilon_src_nodes (const re_dfa_t *dfa, int node, re_node_set *dest_nodes,
const re_node_set *candidates)
{
int ecl_idx;
reg_errcode_t err;
re_node_set *inv_eclosure = dfa->inveclosures + node;
re_node_set except_nodes;
re_node_set_init_empty (&except_nodes);
for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
{
int cur_node = inv_eclosure->elems[ecl_idx];
if (cur_node == node)
continue;
if (IS_EPSILON_NODE (dfa->nodes[cur_node].type))
{
int edst1 = dfa->edests[cur_node].elems[0];
int edst2 = ((dfa->edests[cur_node].nelem > 1)
? dfa->edests[cur_node].elems[1] : -1);
if ((!re_node_set_contains (inv_eclosure, edst1)
&& re_node_set_contains (dest_nodes, edst1))
|| (edst2 > 0
&& !re_node_set_contains (inv_eclosure, edst2)
&& re_node_set_contains (dest_nodes, edst2)))
{
err = re_node_set_add_intersect (&except_nodes, candidates,
dfa->inveclosures + cur_node);
if (BE (err != REG_NOERROR, 0))
{
re_node_set_free (&except_nodes);
return err;
}
}
}
}
for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
{
int cur_node = inv_eclosure->elems[ecl_idx];
if (!re_node_set_contains (&except_nodes, cur_node))
{
int idx = re_node_set_contains (dest_nodes, cur_node) - 1;
re_node_set_remove_at (dest_nodes, idx);
}
}
re_node_set_free (&except_nodes);
return REG_NOERROR;
}
static int
internal_function
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)
{
const re_dfa_t *const dfa = mctx->dfa;
int lim_idx, src_pos, dst_pos;
int dst_bkref_idx = search_cur_bkref_entry (mctx, dst_idx);
int src_bkref_idx = search_cur_bkref_entry (mctx, src_idx);
for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
{
int subexp_idx;
struct re_backref_cache_entry *ent;
ent = mctx->bkref_ents + limits->elems[lim_idx];
subexp_idx = dfa->nodes[ent->node].opr.idx;
dst_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
subexp_idx, dst_node, dst_idx,
dst_bkref_idx);
src_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
subexp_idx, src_node, src_idx,
src_bkref_idx);
/* In case of:
<src> <dst> ( <subexp> )
( <subexp> ) <src> <dst>
( <subexp1> <src> <subexp2> <dst> <subexp3> ) */
if (src_pos == dst_pos)
continue; /* This is unrelated limitation. */
else
return 1;
}
return 0;
}
static int
internal_function
check_dst_limits_calc_pos_1 (const re_match_context_t *mctx, int boundaries,
int subexp_idx, int from_node, int bkref_idx)
{
const re_dfa_t *const dfa = mctx->dfa;
const re_node_set *eclosures = dfa->eclosures + from_node;
int node_idx;
/* Else, we are on the boundary: examine the nodes on the epsilon
closure. */
for (node_idx = 0; node_idx < eclosures->nelem; ++node_idx)
{
int node = eclosures->elems[node_idx];
switch (dfa->nodes[node].type)
{
case OP_BACK_REF:
if (bkref_idx != -1)
{
struct re_backref_cache_entry *ent = mctx->bkref_ents + bkref_idx;
do
{
int dst, cpos;
if (ent->node != node)
continue;
if (subexp_idx < BITSET_WORD_BITS
&& !(ent->eps_reachable_subexps_map
& ((bitset_word_t) 1 << subexp_idx)))
continue;
/* Recurse trying to reach the OP_OPEN_SUBEXP and
OP_CLOSE_SUBEXP cases below. But, if the
destination node is the same node as the source
node, don't recurse because it would cause an
infinite loop: a regex that exhibits this behavior
is ()\1*\1* */
dst = dfa->edests[node].elems[0];
if (dst == from_node)
{
if (boundaries & 1)
return -1;
else /* if (boundaries & 2) */
return 0;
}
cpos =
check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
dst, bkref_idx);
if (cpos == -1 /* && (boundaries & 1) */)
return -1;
if (cpos == 0 && (boundaries & 2))
return 0;
if (subexp_idx < BITSET_WORD_BITS)
ent->eps_reachable_subexps_map
&= ~((bitset_word_t) 1 << subexp_idx);
}
while (ent++->more);
}
break;
case OP_OPEN_SUBEXP:
if ((boundaries & 1) && subexp_idx == dfa->nodes[node].opr.idx)
return -1;
break;
case OP_CLOSE_SUBEXP:
if ((boundaries & 2) && subexp_idx == dfa->nodes[node].opr.idx)
return 0;
break;
default:
break;
}
}
return (boundaries & 2) ? 1 : 0;
}
static int
internal_function
check_dst_limits_calc_pos (const re_match_context_t *mctx, int limit,
int subexp_idx, int from_node, int str_idx,
int bkref_idx)
{
struct re_backref_cache_entry *lim = mctx->bkref_ents + limit;
int boundaries;
/* If we are outside the range of the subexpression, return -1 or 1. */
if (str_idx < lim->subexp_from)
return -1;
if (lim->subexp_to < str_idx)
return 1;
/* If we are within the subexpression, return 0. */
boundaries = (str_idx == lim->subexp_from);
boundaries |= (str_idx == lim->subexp_to) << 1;
if (boundaries == 0)
return 0;
/* Else, examine epsilon closure. */
return check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
from_node, bkref_idx);
}
/* Check the limitations of sub expressions LIMITS, and remove the nodes
which are against limitations from DEST_NODES. */
static reg_errcode_t
internal_function
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)
{
reg_errcode_t err;
int node_idx, lim_idx;
for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
{
int subexp_idx;
struct re_backref_cache_entry *ent;
ent = bkref_ents + limits->elems[lim_idx];
if (str_idx <= ent->subexp_from || ent->str_idx < str_idx)
continue; /* This is unrelated limitation. */
subexp_idx = dfa->nodes[ent->node].opr.idx;
if (ent->subexp_to == str_idx)
{
int ops_node = -1;
int cls_node = -1;
for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
{
int node = dest_nodes->elems[node_idx];
re_token_type_t type = dfa->nodes[node].type;
if (type == OP_OPEN_SUBEXP
&& subexp_idx == dfa->nodes[node].opr.idx)
ops_node = node;
else if (type == OP_CLOSE_SUBEXP
&& subexp_idx == dfa->nodes[node].opr.idx)
cls_node = node;
}
/* Check the limitation of the open subexpression. */
/* Note that (ent->subexp_to = str_idx != ent->subexp_from). */
if (ops_node >= 0)
{
err = sub_epsilon_src_nodes (dfa, ops_node, dest_nodes,
candidates);
if (BE (err != REG_NOERROR, 0))
return err;
}
/* Check the limitation of the close subexpression. */
if (cls_node >= 0)
for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
{
int node = dest_nodes->elems[node_idx];
if (!re_node_set_contains (dfa->inveclosures + node,
cls_node)
&& !re_node_set_contains (dfa->eclosures + node,
cls_node))
{
/* It is against this limitation.
Remove it form the current sifted state. */
err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
candidates);
if (BE (err != REG_NOERROR, 0))
return err;
--node_idx;
}
}
}
else /* (ent->subexp_to != str_idx) */
{
for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
{
int node = dest_nodes->elems[node_idx];
re_token_type_t type = dfa->nodes[node].type;
if (type == OP_CLOSE_SUBEXP || type == OP_OPEN_SUBEXP)
{
if (subexp_idx != dfa->nodes[node].opr.idx)
continue;
/* It is against this limitation.
Remove it form the current sifted state. */
err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
candidates);
if (BE (err != REG_NOERROR, 0))
return err;
}
}
}
}
return REG_NOERROR;
}
static reg_errcode_t
internal_function
sift_states_bkref (const re_match_context_t *mctx, re_sift_context_t *sctx,
int str_idx, const re_node_set *candidates)
{
const re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err;
int node_idx, node;
re_sift_context_t local_sctx;
int first_idx = search_cur_bkref_entry (mctx, str_idx);
if (first_idx == -1)
return REG_NOERROR;
local_sctx.sifted_states = NULL; /* Mark that it hasn't been initialized. */
for (node_idx = 0; node_idx < candidates->nelem; ++node_idx)
{
int enabled_idx;
re_token_type_t type;
struct re_backref_cache_entry *entry;
node = candidates->elems[node_idx];
type = dfa->nodes[node].type;
/* Avoid infinite loop for the REs like "()\1+". */
if (node == sctx->last_node && str_idx == sctx->last_str_idx)
continue;
if (type != OP_BACK_REF)
continue;
entry = mctx->bkref_ents + first_idx;
enabled_idx = first_idx;
do
{
int subexp_len;
int to_idx;
int dst_node;
int ret;
re_dfastate_t *cur_state;
if (entry->node != node)
continue;
subexp_len = entry->subexp_to - entry->subexp_from;
to_idx = str_idx + subexp_len;
dst_node = (subexp_len ? dfa->nexts[node]
: dfa->edests[node].elems[0]);
if (to_idx > sctx->last_str_idx
|| sctx->sifted_states[to_idx] == NULL
|| !STATE_NODE_CONTAINS (sctx->sifted_states[to_idx], dst_node)
|| check_dst_limits (mctx, &sctx->limits, node,
str_idx, dst_node, to_idx))
continue;
if (local_sctx.sifted_states == NULL)
{
local_sctx = *sctx;
err = re_node_set_init_copy (&local_sctx.limits, &sctx->limits);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
local_sctx.last_node = node;
local_sctx.last_str_idx = str_idx;
ret = re_node_set_insert (&local_sctx.limits, enabled_idx);
if (BE (ret < 0, 0))
{
err = REG_ESPACE;
goto free_return;
}
cur_state = local_sctx.sifted_states[str_idx];
err = sift_states_backward (mctx, &local_sctx);
if (BE (err != REG_NOERROR, 0))
goto free_return;
if (sctx->limited_states != NULL)
{
err = merge_state_array (dfa, sctx->limited_states,
local_sctx.sifted_states,
str_idx + 1);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
local_sctx.sifted_states[str_idx] = cur_state;
re_node_set_remove (&local_sctx.limits, enabled_idx);
/* mctx->bkref_ents may have changed, reload the pointer. */
entry = mctx->bkref_ents + enabled_idx;
}
while (enabled_idx++, entry++->more);
}
err = REG_NOERROR;
free_return:
if (local_sctx.sifted_states != NULL)
{
re_node_set_free (&local_sctx.limits);
}
return err;
}
#ifdef RE_ENABLE_I18N
static int
internal_function
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)
{
const re_dfa_t *const dfa = mctx->dfa;
int naccepted;
/* Check the node can accept `multi byte'. */
naccepted = check_node_accept_bytes (dfa, node_idx, &mctx->input, str_idx);
if (naccepted > 0 && str_idx + naccepted <= max_str_idx &&
!STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + naccepted],
dfa->nexts[node_idx]))
/* The node can't accept the `multi byte', or the
destination was already thrown away, then the node
couldn't accept the current input `multi byte'. */
naccepted = 0;
/* Otherwise, it is sure that the node could accept
`naccepted' bytes input. */
return naccepted;
}
#endif /* RE_ENABLE_I18N */
/* Functions for state transition. */
/* Return the next state to which the current state STATE will transit by
accepting the current input byte, and update STATE_LOG if necessary.
If STATE can accept a multibyte char/collating element/back reference
update the destination of STATE_LOG. */
static re_dfastate_t *
internal_function
transit_state (reg_errcode_t *err, re_match_context_t *mctx,
re_dfastate_t *state)
{
re_dfastate_t **trtable;
unsigned char ch;
#ifdef RE_ENABLE_I18N
/* If the current state can accept multibyte. */
if (BE (state->accept_mb, 0))
{
*err = transit_state_mb (mctx, state);
if (BE (*err != REG_NOERROR, 0))
return NULL;
}
#endif /* RE_ENABLE_I18N */
/* Then decide the next state with the single byte. */
#if 0
if (0)
/* don't use transition table */
return transit_state_sb (err, mctx, state);
#endif
/* Use transition table */
ch = re_string_fetch_byte (&mctx->input);
for (;;)
{
trtable = state->trtable;
if (BE (trtable != NULL, 1))
return trtable[ch];
trtable = state->word_trtable;
if (BE (trtable != NULL, 1))
{
unsigned int context;
context
= re_string_context_at (&mctx->input,
re_string_cur_idx (&mctx->input) - 1,
mctx->eflags);
if (IS_WORD_CONTEXT (context))
return trtable[ch + SBC_MAX];
else
return trtable[ch];
}
if (!build_trtable (mctx->dfa, state))
{
*err = REG_ESPACE;
return NULL;
}
/* Retry, we now have a transition table. */
}
}
/* Update the state_log if we need */
static re_dfastate_t *
internal_function
merge_state_with_log (reg_errcode_t *err, re_match_context_t *mctx,
re_dfastate_t *next_state)
{
const re_dfa_t *const dfa = mctx->dfa;
int cur_idx = re_string_cur_idx (&mctx->input);
if (cur_idx > mctx->state_log_top)
{
mctx->state_log[cur_idx] = next_state;
mctx->state_log_top = cur_idx;
}
else if (mctx->state_log[cur_idx] == NULL)
{
mctx->state_log[cur_idx] = next_state;
}
else
{
re_dfastate_t *pstate;
unsigned int context;
re_node_set next_nodes, *log_nodes, *table_nodes = NULL;
/* If (state_log[cur_idx] != 0), it implies that cur_idx is
the destination of a multibyte char/collating element/
back reference. Then the next state is the union set of
these destinations and the results of the transition table. */
pstate = mctx->state_log[cur_idx];
log_nodes = pstate->entrance_nodes;
if (next_state != NULL)
{
table_nodes = next_state->entrance_nodes;
*err = re_node_set_init_union (&next_nodes, table_nodes,
log_nodes);
if (BE (*err != REG_NOERROR, 0))
return NULL;
}
else
next_nodes = *log_nodes;
/* Note: We already add the nodes of the initial state,
then we don't need to add them here. */
context = re_string_context_at (&mctx->input,
re_string_cur_idx (&mctx->input) - 1,
mctx->eflags);
next_state = mctx->state_log[cur_idx]
= re_acquire_state_context (err, dfa, &next_nodes, context);
/* We don't need to check errors here, since the return value of
this function is next_state and ERR is already set. */
if (table_nodes != NULL)
re_node_set_free (&next_nodes);
}
if (BE (dfa->nbackref, 0) && next_state != NULL)
{
/* Check OP_OPEN_SUBEXP in the current state in case that we use them
later. We must check them here, since the back references in the
next state might use them. */
*err = check_subexp_matching_top (mctx, &next_state->nodes,
cur_idx);
if (BE (*err != REG_NOERROR, 0))
return NULL;
/* If the next state has back references. */
if (next_state->has_backref)
{
*err = transit_state_bkref (mctx, &next_state->nodes);
if (BE (*err != REG_NOERROR, 0))
return NULL;
next_state = mctx->state_log[cur_idx];
}
}
return next_state;
}
/* Skip bytes in the input that correspond to part of a
multi-byte match, then look in the log for a state
from which to restart matching. */
static re_dfastate_t *
internal_function
find_recover_state (reg_errcode_t *err, re_match_context_t *mctx)
{
re_dfastate_t *cur_state;
do
{
int max = mctx->state_log_top;
int cur_str_idx = re_string_cur_idx (&mctx->input);
do
{
if (++cur_str_idx > max)
return NULL;
re_string_skip_bytes (&mctx->input, 1);
}
while (mctx->state_log[cur_str_idx] == NULL);
cur_state = merge_state_with_log (err, mctx, NULL);
}
while (*err == REG_NOERROR && cur_state == NULL);
return cur_state;
}
/* Helper functions for transit_state. */
/* From the node set CUR_NODES, pick up the nodes whose types are
OP_OPEN_SUBEXP and which have corresponding back references in the regular
expression. And register them to use them later for evaluating the
corresponding back references. */
static reg_errcode_t
internal_function
check_subexp_matching_top (re_match_context_t *mctx, re_node_set *cur_nodes,
int str_idx)
{
const re_dfa_t *const dfa = mctx->dfa;
int node_idx;
reg_errcode_t err;
/* TODO: This isn't efficient.
Because there might be more than one nodes whose types are
OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
nodes.
E.g. RE: (a){2} */
for (node_idx = 0; node_idx < cur_nodes->nelem; ++node_idx)
{
int node = cur_nodes->elems[node_idx];
if (dfa->nodes[node].type == OP_OPEN_SUBEXP
&& dfa->nodes[node].opr.idx < BITSET_WORD_BITS
&& (dfa->used_bkref_map
& ((bitset_word_t) 1 << dfa->nodes[node].opr.idx)))
{
err = match_ctx_add_subtop (mctx, node, str_idx);
if (BE (err != REG_NOERROR, 0))
return err;
}
}
return REG_NOERROR;
}
#if 0
/* Return the next state to which the current state STATE will transit by
accepting the current input byte. */
static re_dfastate_t *
transit_state_sb (reg_errcode_t *err, re_match_context_t *mctx,
re_dfastate_t *state)
{
const re_dfa_t *const dfa = mctx->dfa;
re_node_set next_nodes;
re_dfastate_t *next_state;
int node_cnt, cur_str_idx = re_string_cur_idx (&mctx->input);
unsigned int context;
*err = re_node_set_alloc (&next_nodes, state->nodes.nelem + 1);
if (BE (*err != REG_NOERROR, 0))
return NULL;
for (node_cnt = 0; node_cnt < state->nodes.nelem; ++node_cnt)
{
int cur_node = state->nodes.elems[node_cnt];
if (check_node_accept (mctx, dfa->nodes + cur_node, cur_str_idx))
{
*err = re_node_set_merge (&next_nodes,
dfa->eclosures + dfa->nexts[cur_node]);
if (BE (*err != REG_NOERROR, 0))
{
re_node_set_free (&next_nodes);
return NULL;
}
}
}
context = re_string_context_at (&mctx->input, cur_str_idx, mctx->eflags);
next_state = re_acquire_state_context (err, dfa, &next_nodes, context);
/* We don't need to check errors here, since the return value of
this function is next_state and ERR is already set. */
re_node_set_free (&next_nodes);
re_string_skip_bytes (&mctx->input, 1);
return next_state;
}
#endif
#ifdef RE_ENABLE_I18N
static reg_errcode_t
internal_function
transit_state_mb (re_match_context_t *mctx, re_dfastate_t *pstate)
{
const re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err;
int i;
for (i = 0; i < pstate->nodes.nelem; ++i)
{
re_node_set dest_nodes, *new_nodes;
int cur_node_idx = pstate->nodes.elems[i];
int naccepted, dest_idx;
unsigned int context;
re_dfastate_t *dest_state;
if (!dfa->nodes[cur_node_idx].accept_mb)
continue;
if (dfa->nodes[cur_node_idx].constraint)
{
context = re_string_context_at (&mctx->input,
re_string_cur_idx (&mctx->input),
mctx->eflags);
if (NOT_SATISFY_NEXT_CONSTRAINT (dfa->nodes[cur_node_idx].constraint,
context))
continue;
}
/* How many bytes the node can accept? */
naccepted = check_node_accept_bytes (dfa, cur_node_idx, &mctx->input,
re_string_cur_idx (&mctx->input));
if (naccepted == 0)
continue;
/* The node can accepts `naccepted' bytes. */
dest_idx = re_string_cur_idx (&mctx->input) + naccepted;
mctx->max_mb_elem_len = ((mctx->max_mb_elem_len < naccepted) ? naccepted
: mctx->max_mb_elem_len);
err = clean_state_log_if_needed (mctx, dest_idx);
if (BE (err != REG_NOERROR, 0))
return err;
#ifdef DEBUG
assert (dfa->nexts[cur_node_idx] != -1);
#endif
new_nodes = dfa->eclosures + dfa->nexts[cur_node_idx];
dest_state = mctx->state_log[dest_idx];
if (dest_state == NULL)
dest_nodes = *new_nodes;
else
{
err = re_node_set_init_union (&dest_nodes,
dest_state->entrance_nodes, new_nodes);
if (BE (err != REG_NOERROR, 0))
return err;
}
context = re_string_context_at (&mctx->input, dest_idx - 1,
mctx->eflags);
mctx->state_log[dest_idx]
= re_acquire_state_context (&err, dfa, &dest_nodes, context);
if (dest_state != NULL)
re_node_set_free (&dest_nodes);
if (BE (mctx->state_log[dest_idx] == NULL && err != REG_NOERROR, 0))
return err;
}
return REG_NOERROR;
}
#endif /* RE_ENABLE_I18N */
static reg_errcode_t
internal_function
transit_state_bkref (re_match_context_t *mctx, const re_node_set *nodes)
{
const re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err;
int i;
int cur_str_idx = re_string_cur_idx (&mctx->input);
for (i = 0; i < nodes->nelem; ++i)
{
int dest_str_idx, prev_nelem, bkc_idx;
int node_idx = nodes->elems[i];
unsigned int context;
const re_token_t *node = dfa->nodes + node_idx;
re_node_set *new_dest_nodes;
/* Check whether `node' is a backreference or not. */
if (node->type != OP_BACK_REF)
continue;
if (node->constraint)
{
context = re_string_context_at (&mctx->input, cur_str_idx,
mctx->eflags);
if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
continue;
}
/* `node' is a backreference.
Check the substring which the substring matched. */
bkc_idx = mctx->nbkref_ents;
err = get_subexp (mctx, node_idx, cur_str_idx);
if (BE (err != REG_NOERROR, 0))
goto free_return;
/* And add the epsilon closures (which is `new_dest_nodes') of
the backreference to appropriate state_log. */
#ifdef DEBUG
assert (dfa->nexts[node_idx] != -1);
#endif
for (; bkc_idx < mctx->nbkref_ents; ++bkc_idx)
{
int subexp_len;
re_dfastate_t *dest_state;
struct re_backref_cache_entry *bkref_ent;
bkref_ent = mctx->bkref_ents + bkc_idx;
if (bkref_ent->node != node_idx || bkref_ent->str_idx != cur_str_idx)
continue;
subexp_len = bkref_ent->subexp_to - bkref_ent->subexp_from;
new_dest_nodes = (subexp_len == 0
? dfa->eclosures + dfa->edests[node_idx].elems[0]
: dfa->eclosures + dfa->nexts[node_idx]);
dest_str_idx = (cur_str_idx + bkref_ent->subexp_to
- bkref_ent->subexp_from);
context = re_string_context_at (&mctx->input, dest_str_idx - 1,
mctx->eflags);
dest_state = mctx->state_log[dest_str_idx];
prev_nelem = ((mctx->state_log[cur_str_idx] == NULL) ? 0
: mctx->state_log[cur_str_idx]->nodes.nelem);
/* Add `new_dest_node' to state_log. */
if (dest_state == NULL)
{
mctx->state_log[dest_str_idx]
= re_acquire_state_context (&err, dfa, new_dest_nodes,
context);
if (BE (mctx->state_log[dest_str_idx] == NULL
&& err != REG_NOERROR, 0))
goto free_return;
}
else
{
re_node_set dest_nodes;
err = re_node_set_init_union (&dest_nodes,
dest_state->entrance_nodes,
new_dest_nodes);
if (BE (err != REG_NOERROR, 0))
{
re_node_set_free (&dest_nodes);
goto free_return;
}
mctx->state_log[dest_str_idx]
= re_acquire_state_context (&err, dfa, &dest_nodes, context);
re_node_set_free (&dest_nodes);
if (BE (mctx->state_log[dest_str_idx] == NULL
&& err != REG_NOERROR, 0))
goto free_return;
}
/* We need to check recursively if the backreference can epsilon
transit. */
if (subexp_len == 0
&& mctx->state_log[cur_str_idx]->nodes.nelem > prev_nelem)
{
err = check_subexp_matching_top (mctx, new_dest_nodes,
cur_str_idx);
if (BE (err != REG_NOERROR, 0))
goto free_return;
err = transit_state_bkref (mctx, new_dest_nodes);
if (BE (err != REG_NOERROR, 0))
goto free_return;
}
}
}
err = REG_NOERROR;
free_return:
return err;
}
/* Enumerate all the candidates which the backreference BKREF_NODE can match
at BKREF_STR_IDX, and register them by match_ctx_add_entry().
Note that we might collect inappropriate candidates here.
However, the cost of checking them strictly here is too high, then we
delay these checking for prune_impossible_nodes(). */
static reg_errcode_t
internal_function
get_subexp (re_match_context_t *mctx, int bkref_node, int bkref_str_idx)
{
const re_dfa_t *const dfa = mctx->dfa;
int subexp_num, sub_top_idx;
const char *buf = (const char *) re_string_get_buffer (&mctx->input);
/* Return if we have already checked BKREF_NODE at BKREF_STR_IDX. */
int cache_idx = search_cur_bkref_entry (mctx, bkref_str_idx);
if (cache_idx != -1)
{
const struct re_backref_cache_entry *entry
= mctx->bkref_ents + cache_idx;
do
if (entry->node == bkref_node)
return REG_NOERROR; /* We already checked it. */
while (entry++->more);
}
subexp_num = dfa->nodes[bkref_node].opr.idx;
/* For each sub expression */
for (sub_top_idx = 0; sub_top_idx < mctx->nsub_tops; ++sub_top_idx)
{
reg_errcode_t err;
re_sub_match_top_t *sub_top = mctx->sub_tops[sub_top_idx];
re_sub_match_last_t *sub_last;
int sub_last_idx, sl_str, bkref_str_off;
if (dfa->nodes[sub_top->node].opr.idx != subexp_num)
continue; /* It isn't related. */
sl_str = sub_top->str_idx;
bkref_str_off = bkref_str_idx;
/* At first, check the last node of sub expressions we already
evaluated. */
for (sub_last_idx = 0; sub_last_idx < sub_top->nlasts; ++sub_last_idx)
{
int sl_str_diff;
sub_last = sub_top->lasts[sub_last_idx];
sl_str_diff = sub_last->str_idx - sl_str;
/* The matched string by the sub expression match with the substring
at the back reference? */
if (sl_str_diff > 0)
{
if (BE (bkref_str_off + sl_str_diff > mctx->input.valid_len, 0))
{
/* Not enough chars for a successful match. */
if (bkref_str_off + sl_str_diff > mctx->input.len)
break;
err = clean_state_log_if_needed (mctx,
bkref_str_off
+ sl_str_diff);
if (BE (err != REG_NOERROR, 0))
return err;
buf = (const char *) re_string_get_buffer (&mctx->input);
}
if (memcmp (buf + bkref_str_off, buf + sl_str, sl_str_diff) != 0)
/* We don't need to search this sub expression any more. */
break;
}
bkref_str_off += sl_str_diff;
sl_str += sl_str_diff;
err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
bkref_str_idx);
/* Reload buf, since the preceding call might have reallocated
the buffer. */
buf = (const char *) re_string_get_buffer (&mctx->input);
if (err == REG_NOMATCH)
continue;
if (BE (err != REG_NOERROR, 0))
return err;
}
if (sub_last_idx < sub_top->nlasts)
continue;
if (sub_last_idx > 0)
++sl_str;
/* Then, search for the other last nodes of the sub expression. */
for (; sl_str <= bkref_str_idx; ++sl_str)
{
int cls_node, sl_str_off;
const re_node_set *nodes;
sl_str_off = sl_str - sub_top->str_idx;
/* The matched string by the sub expression match with the substring
at the back reference? */
if (sl_str_off > 0)
{
if (BE (bkref_str_off >= mctx->input.valid_len, 0))
{
/* If we are at the end of the input, we cannot match. */
if (bkref_str_off >= mctx->input.len)
break;
err = extend_buffers (mctx);
if (BE (err != REG_NOERROR, 0))
return err;
buf = (const char *) re_string_get_buffer (&mctx->input);
}
if (buf [bkref_str_off++] != buf[sl_str - 1])
break; /* We don't need to search this sub expression
any more. */
}
if (mctx->state_log[sl_str] == NULL)
continue;
/* Does this state have a ')' of the sub expression? */
nodes = &mctx->state_log[sl_str]->nodes;
cls_node = find_subexp_node (dfa, nodes, subexp_num,
OP_CLOSE_SUBEXP);
if (cls_node == -1)
continue; /* No. */
if (sub_top->path == NULL)
{
sub_top->path = calloc (sl_str - sub_top->str_idx + 1,
sizeof (state_array_t));
if (sub_top->path == NULL)
return REG_ESPACE;
}
/* Can the OP_OPEN_SUBEXP node arrive the OP_CLOSE_SUBEXP node
in the current context? */
err = check_arrival (mctx, sub_top->path, sub_top->node,
sub_top->str_idx, cls_node, sl_str,
OP_CLOSE_SUBEXP);
if (err == REG_NOMATCH)
continue;
if (BE (err != REG_NOERROR, 0))
return err;
sub_last = match_ctx_add_sublast (sub_top, cls_node, sl_str);
if (BE (sub_last == NULL, 0))
return REG_ESPACE;
err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
bkref_str_idx);
if (err == REG_NOMATCH)
continue;
}
}
return REG_NOERROR;
}
/* Helper functions for get_subexp(). */
/* Check SUB_LAST can arrive to the back reference BKREF_NODE at BKREF_STR.
If it can arrive, register the sub expression expressed with SUB_TOP
and SUB_LAST. */
static reg_errcode_t
internal_function
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)
{
reg_errcode_t err;
int to_idx;
/* Can the subexpression arrive the back reference? */
err = check_arrival (mctx, &sub_last->path, sub_last->node,
sub_last->str_idx, bkref_node, bkref_str,
OP_OPEN_SUBEXP);
if (err != REG_NOERROR)
return err;
err = match_ctx_add_entry (mctx, bkref_node, bkref_str, sub_top->str_idx,
sub_last->str_idx);
if (BE (err != REG_NOERROR, 0))
return err;
to_idx = bkref_str + sub_last->str_idx - sub_top->str_idx;
return clean_state_log_if_needed (mctx, to_idx);
}
/* Find the first node which is '(' or ')' and whose index is SUBEXP_IDX.
Search '(' if FL_OPEN, or search ')' otherwise.
TODO: This function isn't efficient...
Because there might be more than one nodes whose types are
OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
nodes.
E.g. RE: (a){2} */
static int
internal_function
find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
int subexp_idx, int type)
{
int cls_idx;
for (cls_idx = 0; cls_idx < nodes->nelem; ++cls_idx)
{
int cls_node = nodes->elems[cls_idx];
const re_token_t *node = dfa->nodes + cls_node;
if (node->type == type
&& node->opr.idx == subexp_idx)
return cls_node;
}
return -1;
}
/* Check whether the node TOP_NODE at TOP_STR can arrive to the node
LAST_NODE at LAST_STR. We record the path onto PATH since it will be
heavily reused.
Return REG_NOERROR if it can arrive, or REG_NOMATCH otherwise. */
static reg_errcode_t
internal_function
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)
{
const re_dfa_t *const dfa = mctx->dfa;
reg_errcode_t err = REG_NOERROR;
int subexp_num, backup_cur_idx, str_idx, null_cnt;
re_dfastate_t *cur_state = NULL;
re_node_set *cur_nodes, next_nodes;
re_dfastate_t **backup_state_log;
unsigned int context;
subexp_num = dfa->nodes[top_node].opr.idx;
/* Extend the buffer if we need. */
if (BE (path->alloc < last_str + mctx->max_mb_elem_len + 1, 0))
{
re_dfastate_t **new_array;
int old_alloc = path->alloc;
path->alloc += last_str + mctx->max_mb_elem_len + 1;
new_array = re_realloc (path->array, re_dfastate_t *, path->alloc);
if (BE (new_array == NULL, 0))
{
path->alloc = old_alloc;
return REG_ESPACE;
}
path->array = new_array;
memset (new_array + old_alloc, '\0',
sizeof (re_dfastate_t *) * (path->alloc - old_alloc));
}
str_idx = path->next_idx ? path->next_idx : top_str;