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sortix--sortix/libc/regex/regexec.cpp
Jonas 'Sortie' Termansen 75808c637d Add regex(3).
2015-12-17 23:32:43 +01:00

253 lines
7.2 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2014, 2015.
This file is part of the Sortix C Library.
The Sortix 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 3 of the License, or (at your
option) any later version.
The Sortix 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 Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
regex/regexec.cpp
Regular expression execution.
*******************************************************************************/
#include <assert.h>
#include <regex.h>
#include <pthread.h>
#define QUEUE_CURRENT_STATE(new_state) \
{ \
if ( !new_state ) \
{ \
match = true; \
for ( struct re* re = state->re_current_state_next; \
re; \
re = re->re_current_state_next ) \
re->re_is_current = 0; \
state->re_current_state_next = NULL; \
current_states_last = state; \
} \
else if ( !(new_state->re_is_current && new_state->re_is_currently_done) ) \
{ \
if ( new_state->re_is_current ) \
{ \
if ( new_state->re_current_state_prev ) \
new_state->re_current_state_prev->re_current_state_next = \
new_state->re_current_state_next; \
else \
current_states = new_state->re_current_state_next; \
if ( new_state->re_current_state_next ) \
new_state->re_current_state_next->re_current_state_prev = \
new_state->re_current_state_prev; \
else \
current_states_last = new_state->re_current_state_prev; \
} \
new_state->re_current_state_prev = state; \
new_state->re_current_state_next = state->re_current_state_next; \
if ( state->re_current_state_next ) \
state->re_current_state_next->re_current_state_prev = new_state; \
else \
current_states_last = new_state; \
state->re_current_state_next = new_state; \
new_state->re_is_currently_done = 0; \
new_state->re_is_current = 1; \
new_state->re_is_upcoming = 0; \
for ( size_t m = 0; m < nmatch; m++ ) \
new_state->re_matches[m] = state->re_matches[m]; \
} \
} \
#define QUEUE_UPCOMING_STATE(new_state) \
{ \
if ( !new_state ) \
{ \
consumed_char = true; \
match = true; \
for ( struct re* re = state->re_current_state_next; \
re; \
re = re->re_current_state_next ) \
re->re_is_current = 0; \
state->re_current_state_next = NULL; \
current_states_last = state; \
} \
else if ( !new_state->re_is_upcoming ) \
{ \
if ( !upcoming_states ) \
upcoming_states = new_state; \
if ( upcoming_states_last ) \
upcoming_states_last->re_upcoming_state_next = new_state; \
upcoming_states_last = new_state; \
new_state->re_upcoming_state_next = NULL; \
new_state->re_is_upcoming = 1; \
for ( size_t m = 0; m < nmatch; m++ ) \
new_state->re_matches[m] = state->re_matches[m]; \
} \
} \
extern "C"
int regexec(const regex_t* restrict regex_const,
const char* restrict string,
size_t nmatch,
regmatch_t* restrict pmatch,
int eflags)
{
// TODO: Sanitize eflags.
regex_t* regex = (regex_t*) regex_const;
pthread_mutex_lock(&regex->re_lock);
if ( regex->re_cflags & REG_NOSUB )
nmatch = 0;
for ( size_t i = 0; i < nmatch; i++ )
{
pmatch[i].rm_so = -1;
pmatch[i].rm_eo = -1;
}
if ( regex->re_nsub + 1 < nmatch )
nmatch = regex->re_nsub + 1;
int result = REG_NOMATCH;
struct re* current_states = NULL;
struct re* current_states_last = NULL;
struct re* upcoming_states = NULL;
struct re* upcoming_states_last = NULL;
regex->re->re_is_current = 0;
for ( size_t i = 0; true; i++ )
{
if ( !regex->re->re_is_current && result == REG_NOMATCH )
{
if ( current_states_last )
current_states_last->re_current_state_next = regex->re;
else
current_states = regex->re;
regex->re->re_current_state_prev = current_states_last;
regex->re->re_current_state_next = NULL;
current_states_last = regex->re;
regex->re->re_is_currently_done = 0;
regex->re->re_is_current = 1;
regex->re->re_is_upcoming = 0;
for ( size_t m = 0; m < nmatch; m++ )
{
regex->re->re_matches[m].rm_so = m == 0 ? i : -1;
regex->re->re_matches[m].rm_eo = -1;
}
}
char c = string[i];
for ( struct re* state = current_states;
state;
state = state->re_current_state_next )
{
bool match = false;
bool consumed_char = false;
if ( state->re_type == RE_TYPE_BOL )
{
if ( !(eflags & REG_NOTBOL) )
QUEUE_CURRENT_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_EOL )
{
if ( !(eflags & REG_NOTEOL) && c == '\0' )
QUEUE_CURRENT_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_CHAR )
{
if ( c != '\0' && state->re_char.c == c )
QUEUE_UPCOMING_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_ANY_CHAR )
{
if ( c != '\0' )
QUEUE_UPCOMING_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_SET )
{
unsigned char uc = c;
if ( c != '\0' && (state->re_set.set[uc / 8] & (1 << (uc % 8))) )
QUEUE_UPCOMING_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_SUBEXPRESSION )
{
size_t index = state->re_subexpression.index;
state->re_matches[index].rm_so = i;
QUEUE_CURRENT_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_SUBEXPRESSION_END )
{
size_t index = state->re_subexpression.index;
state->re_matches[index].rm_eo = i;
QUEUE_CURRENT_STATE(state->re_next);
}
else if ( state->re_type == RE_TYPE_ALTERNATIVE ||
state->re_type == RE_TYPE_OPTIONAL ||
state->re_type == RE_TYPE_LOOP )
{
QUEUE_CURRENT_STATE(state->re_split.re);
QUEUE_CURRENT_STATE(state->re_next);
}
state->re_is_currently_done = 1;
if ( match )
{
state->re_matches[0].rm_eo = i + consumed_char;
for ( size_t m = 0; m < nmatch; m++ )
pmatch[m] = state->re_matches[m];
result = 0;
if ( nmatch == 0 )
break;
}
}
for ( struct re* re = current_states; re; re = re->re_current_state_next )
re->re_is_current = 0;
if ( nmatch == 0 && result == 0 )
{
for ( struct re* re = upcoming_states; re; re = re->re_upcoming_state_next )
re->re_is_upcoming = 0;
break;
}
current_states = upcoming_states;
if ( current_states )
current_states->re_current_state_prev = NULL;
current_states_last = upcoming_states_last;
for ( struct re* re = current_states; re; re = re->re_current_state_next )
{
re->re_is_currently_done = 0;
re->re_is_current = 1;
re->re_is_upcoming = 0;
re->re_current_state_next = re->re_upcoming_state_next;
if ( re->re_current_state_next )
re->re_current_state_next->re_current_state_prev = re;
}
upcoming_states = NULL;
upcoming_states_last = NULL;
eflags |= REG_NOTBOL;
if ( current_states == NULL && result == 0 )
break;
if ( c == '\0' )
break;
}
pthread_mutex_unlock(&regex->re_lock);
return result;
}