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Posted to commits@hawq.apache.org by zt...@apache.org on 2022/01/03 09:09:09 UTC
[hawq] 01/03: HAWQ-1824. Fix infinite loop problem of regex match function
This is an automated email from the ASF dual-hosted git repository.
ztao1987 pushed a commit to branch ztao
in repository https://gitbox.apache.org/repos/asf/hawq.git
commit d5caf58d746145a00fdfc0ac7045f7169dce1911
Author: ztao1987 <zh...@gmail.com>
AuthorDate: Mon Jan 3 17:02:52 2022 +0800
HAWQ-1824. Fix infinite loop problem of regex match function
---
src/backend/regex/regc_nfa.c | 2493 ++++++++++++++++++++----------------------
src/backend/regex/regcomp.c | 12 +-
2 files changed, 1190 insertions(+), 1315 deletions(-)
diff --git a/src/backend/regex/regc_nfa.c b/src/backend/regex/regc_nfa.c
index ef56630..3d7b3bb 100644
--- a/src/backend/regex/regc_nfa.c
+++ b/src/backend/regex/regc_nfa.c
@@ -28,7 +28,8 @@
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
- * $PostgreSQL: pgsql/src/backend/regex/regc_nfa.c,v 1.7 2009/06/11 14:49:01 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/regex/regc_nfa.c,v 1.7 2009/06/11 14:49:01
+ * momjian Exp $
*
*
* One or two things that technically ought to be in here
@@ -36,452 +37,416 @@
* the color chains.
*/
-#define NISERR() VISERR(nfa->v)
-#define NERR(e) VERR(nfa->v, (e))
-
+#define NISERR() VISERR(nfa->v)
+#define NERR(e) VERR(nfa->v, (e))
/*
* newnfa - set up an NFA
*/
-static struct nfa * /* the NFA, or NULL */
-newnfa(struct vars * v,
- struct colormap * cm,
- struct nfa * parent) /* NULL if primary NFA */
+static struct nfa * /* the NFA, or NULL */
+newnfa(struct vars *v, struct colormap *cm,
+ struct nfa *parent) /* NULL if primary NFA */
{
- struct nfa *nfa;
-
- nfa = (struct nfa *) MALLOC(sizeof(struct nfa));
- if (nfa == NULL)
- return NULL;
-
- nfa->states = NULL;
- nfa->slast = NULL;
- nfa->free = NULL;
- nfa->nstates = 0;
- nfa->cm = cm;
- nfa->v = v;
- nfa->size = 0;
- nfa->bos[0] = nfa->bos[1] = COLORLESS;
- nfa->eos[0] = nfa->eos[1] = COLORLESS;
- nfa->parent = parent; /* Precedes newfstate so parent is valid. */
- nfa->post = newfstate(nfa, '@'); /* number 0 */
- nfa->pre = newfstate(nfa, '>'); /* number 1 */
-
- nfa->init = newstate(nfa); /* may become invalid later */
- nfa->final = newstate(nfa);
- if (ISERR())
- {
- freenfa(nfa);
- return NULL;
- }
- rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init);
- newarc(nfa, '^', 1, nfa->pre, nfa->init);
- newarc(nfa, '^', 0, nfa->pre, nfa->init);
- rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post);
- newarc(nfa, '$', 1, nfa->final, nfa->post);
- newarc(nfa, '$', 0, nfa->final, nfa->post);
-
- if (ISERR())
- {
- freenfa(nfa);
- return NULL;
- }
- return nfa;
+ struct nfa *nfa;
+
+ nfa = (struct nfa *)MALLOC(sizeof(struct nfa));
+ if (nfa == NULL) return NULL;
+
+ nfa->states = NULL;
+ nfa->slast = NULL;
+ nfa->free = NULL;
+ nfa->nstates = 0;
+ nfa->cm = cm;
+ nfa->v = v;
+ nfa->size = 0;
+ nfa->bos[0] = nfa->bos[1] = COLORLESS;
+ nfa->eos[0] = nfa->eos[1] = COLORLESS;
+ nfa->parent = parent; /* Precedes newfstate so parent is valid. */
+ nfa->post = newfstate(nfa, '@'); /* number 0 */
+ nfa->pre = newfstate(nfa, '>'); /* number 1 */
+
+ nfa->init = newstate(nfa); /* may become invalid later */
+ nfa->final = newstate(nfa);
+ if (ISERR()) {
+ freenfa(nfa);
+ return NULL;
+ }
+ rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init);
+ newarc(nfa, '^', 1, nfa->pre, nfa->init);
+ newarc(nfa, '^', 0, nfa->pre, nfa->init);
+ rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post);
+ newarc(nfa, '$', 1, nfa->final, nfa->post);
+ newarc(nfa, '$', 0, nfa->final, nfa->post);
+
+ if (ISERR()) {
+ freenfa(nfa);
+ return NULL;
+ }
+ return nfa;
}
/*
* TooManyStates - checks if the max states exceeds the compile-time value
*/
-static int
-TooManyStates(struct nfa * nfa)
-{
- struct nfa *parent = nfa->parent;
- size_t sz = nfa->size;
-
- while (parent != NULL)
- {
- sz = parent->size;
- parent = parent->parent;
- }
- if (sz > REG_MAX_STATES)
- return 1;
- return 0;
+static int TooManyStates(struct nfa *nfa) {
+ struct nfa *parent = nfa->parent;
+ size_t sz = nfa->size;
+
+ while (parent != NULL) {
+ sz = parent->size;
+ parent = parent->parent;
+ }
+ if (sz > REG_MAX_STATES) return 1;
+ return 0;
}
/*
* IncrementSize - increases the tracked size of the NFA and its parents.
*/
-static void
-IncrementSize(struct nfa * nfa)
-{
- struct nfa *parent = nfa->parent;
-
- nfa->size++;
- while (parent != NULL)
- {
- parent->size++;
- parent = parent->parent;
- }
+static void IncrementSize(struct nfa *nfa) {
+ struct nfa *parent = nfa->parent;
+
+ nfa->size++;
+ while (parent != NULL) {
+ parent->size++;
+ parent = parent->parent;
+ }
}
/*
* DecrementSize - decreases the tracked size of the NFA and its parents.
*/
-static void
-DecrementSize(struct nfa * nfa)
-{
- struct nfa *parent = nfa->parent;
-
- nfa->size--;
- while (parent != NULL)
- {
- parent->size--;
- parent = parent->parent;
- }
+static void DecrementSize(struct nfa *nfa) {
+ struct nfa *parent = nfa->parent;
+
+ nfa->size--;
+ while (parent != NULL) {
+ parent->size--;
+ parent = parent->parent;
+ }
}
/*
* freenfa - free an entire NFA
*/
-static void
-freenfa(struct nfa * nfa)
-{
- struct state *s;
-
- while ((s = nfa->states) != NULL)
- {
- s->nins = s->nouts = 0; /* don't worry about arcs */
- freestate(nfa, s);
- }
- while ((s = nfa->free) != NULL)
- {
- nfa->free = s->next;
- destroystate(nfa, s);
- }
-
- nfa->slast = NULL;
- nfa->nstates = -1;
- nfa->pre = NULL;
- nfa->post = NULL;
- FREE(nfa);
+static void freenfa(struct nfa *nfa) {
+ struct state *s;
+
+ while ((s = nfa->states) != NULL) {
+ s->nins = s->nouts = 0; /* don't worry about arcs */
+ freestate(nfa, s);
+ }
+ while ((s = nfa->free) != NULL) {
+ nfa->free = s->next;
+ destroystate(nfa, s);
+ }
+
+ nfa->slast = NULL;
+ nfa->nstates = -1;
+ nfa->pre = NULL;
+ nfa->post = NULL;
+ FREE(nfa);
}
/*
* newstate - allocate an NFA state, with zero flag value
*/
-static struct state * /* NULL on error */
-newstate(struct nfa * nfa)
-{
- struct state *s;
-
- if (TooManyStates(nfa))
- {
- NERR(REG_ETOOBIG);
- return NULL;
- }
- if (nfa->free != NULL)
- {
- s = nfa->free;
- nfa->free = s->next;
- }
- else
- {
- s = (struct state *) MALLOC(sizeof(struct state));
- if (s == NULL)
- {
- NERR(REG_ESPACE);
- return NULL;
- }
- s->oas.next = NULL;
- s->free = NULL;
- s->noas = 0;
- }
-
- assert(nfa->nstates >= 0);
- s->no = nfa->nstates++;
- s->flag = 0;
- if (nfa->states == NULL)
- nfa->states = s;
- s->nins = 0;
- s->ins = NULL;
- s->nouts = 0;
- s->outs = NULL;
- s->tmp = NULL;
- s->next = NULL;
- if (nfa->slast != NULL)
- {
- assert(nfa->slast->next == NULL);
- nfa->slast->next = s;
- }
- s->prev = nfa->slast;
- nfa->slast = s;
- /* track the current size and the parent size */
- IncrementSize(nfa);
- return s;
+static struct state * /* NULL on error */
+newstate(struct nfa *nfa) {
+ struct state *s;
+
+ if (TooManyStates(nfa)) {
+ NERR(REG_ETOOBIG);
+ return NULL;
+ }
+ if (nfa->free != NULL) {
+ s = nfa->free;
+ nfa->free = s->next;
+ } else {
+ s = (struct state *)MALLOC(sizeof(struct state));
+ if (s == NULL) {
+ NERR(REG_ESPACE);
+ return NULL;
+ }
+ s->oas.next = NULL;
+ s->free = NULL;
+ s->noas = 0;
+ }
+
+ assert(nfa->nstates >= 0);
+ s->no = nfa->nstates++;
+ s->flag = 0;
+ if (nfa->states == NULL) nfa->states = s;
+ s->nins = 0;
+ s->ins = NULL;
+ s->nouts = 0;
+ s->outs = NULL;
+ s->tmp = NULL;
+ s->next = NULL;
+ if (nfa->slast != NULL) {
+ assert(nfa->slast->next == NULL);
+ nfa->slast->next = s;
+ }
+ s->prev = nfa->slast;
+ nfa->slast = s;
+ /* track the current size and the parent size */
+ IncrementSize(nfa);
+ return s;
}
/*
* newfstate - allocate an NFA state with a specified flag value
*/
-static struct state * /* NULL on error */
-newfstate(struct nfa * nfa, int flag)
-{
- struct state *s;
+static struct state * /* NULL on error */
+newfstate(struct nfa *nfa, int flag) {
+ struct state *s;
- s = newstate(nfa);
- if (s != NULL)
- s->flag = (char) flag;
- return s;
+ s = newstate(nfa);
+ if (s != NULL) s->flag = (char)flag;
+ return s;
}
/*
* dropstate - delete a state's inarcs and outarcs and free it
*/
-static void
-dropstate(struct nfa * nfa,
- struct state * s)
-{
- struct arc *a;
+static void dropstate(struct nfa *nfa, struct state *s) {
+ struct arc *a;
- while ((a = s->ins) != NULL)
- freearc(nfa, a);
- while ((a = s->outs) != NULL)
- freearc(nfa, a);
- freestate(nfa, s);
+ while ((a = s->ins) != NULL) freearc(nfa, a);
+ while ((a = s->outs) != NULL) freearc(nfa, a);
+ freestate(nfa, s);
}
/*
* freestate - free a state, which has no in-arcs or out-arcs
*/
-static void
-freestate(struct nfa * nfa,
- struct state * s)
-{
- assert(s != NULL);
- assert(s->nins == 0 && s->nouts == 0);
-
- s->no = FREESTATE;
- s->flag = 0;
- if (s->next != NULL)
- s->next->prev = s->prev;
- else
- {
- assert(s == nfa->slast);
- nfa->slast = s->prev;
- }
- if (s->prev != NULL)
- s->prev->next = s->next;
- else
- {
- assert(s == nfa->states);
- nfa->states = s->next;
- }
- s->prev = NULL;
- s->next = nfa->free; /* don't delete it, put it on the free list */
- nfa->free = s;
- DecrementSize(nfa);
+static void freestate(struct nfa *nfa, struct state *s) {
+ assert(s != NULL);
+ assert(s->nins == 0 && s->nouts == 0);
+
+ s->no = FREESTATE;
+ s->flag = 0;
+ if (s->next != NULL)
+ s->next->prev = s->prev;
+ else {
+ assert(s == nfa->slast);
+ nfa->slast = s->prev;
+ }
+ if (s->prev != NULL)
+ s->prev->next = s->next;
+ else {
+ assert(s == nfa->states);
+ nfa->states = s->next;
+ }
+ s->prev = NULL;
+ s->next = nfa->free; /* don't delete it, put it on the free list */
+ nfa->free = s;
+ DecrementSize(nfa);
}
/*
* destroystate - really get rid of an already-freed state
*/
-static void
-destroystate(struct nfa * nfa,
- struct state * s)
-{
- struct arcbatch *ab;
- struct arcbatch *abnext;
-
- assert(s->no == FREESTATE);
- for (ab = s->oas.next; ab != NULL; ab = abnext)
- {
- abnext = ab->next;
- FREE(ab);
- }
- s->ins = NULL;
- s->outs = NULL;
- s->next = NULL;
- FREE(s);
+static void destroystate(struct nfa *nfa, struct state *s) {
+ struct arcbatch *ab;
+ struct arcbatch *abnext;
+
+ assert(s->no == FREESTATE);
+ for (ab = s->oas.next; ab != NULL; ab = abnext) {
+ abnext = ab->next;
+ FREE(ab);
+ }
+ s->ins = NULL;
+ s->outs = NULL;
+ s->next = NULL;
+ FREE(s);
}
/*
* newarc - set up a new arc within an NFA
*/
-static void
-newarc(struct nfa * nfa,
- int t,
- pcolor co,
- struct state * from,
- struct state * to)
-{
- struct arc *a;
-
- assert(from != NULL && to != NULL);
-
- /* check for duplicates */
- for (a = from->outs; a != NULL; a = a->outchain)
- if (a->to == to && a->co == co && a->type == t)
- return;
-
- a = allocarc(nfa, from);
- if (NISERR())
- return;
- assert(a != NULL);
-
- a->type = t;
- a->co = (color) co;
- a->to = to;
- a->from = from;
-
- /*
- * Put the new arc on the beginning, not the end, of the chains. Not only
- * is this easier, it has the very useful side effect that deleting the
- * most-recently-added arc is the cheapest case rather than the most
- * expensive one.
- */
- a->inchain = to->ins;
- to->ins = a;
- a->outchain = from->outs;
- from->outs = a;
-
- from->nouts++;
- to->nins++;
-
- if (COLORED(a) && nfa->parent == NULL)
- colorchain(nfa->cm, a);
+static void newarc(struct nfa *nfa, int t, pcolor co, struct state *from,
+ struct state *to) {
+ struct arc *a;
+
+ assert(from != NULL && to != NULL);
+
+ /* check for duplicates */
+ for (a = from->outs; a != NULL; a = a->outchain)
+ if (a->to == to && a->co == co && a->type == t) return;
+
+ a = allocarc(nfa, from);
+ if (NISERR()) return;
+ assert(a != NULL);
+
+ a->type = t;
+ a->co = (color)co;
+ a->to = to;
+ a->from = from;
+
+ /*
+ * Put the new arc on the beginning, not the end, of the chains. Not only
+ * is this easier, it has the very useful side effect that deleting the
+ * most-recently-added arc is the cheapest case rather than the most
+ * expensive one.
+ */
+ a->inchain = to->ins;
+ to->ins = a;
+ a->outchain = from->outs;
+ from->outs = a;
+
+ from->nouts++;
+ to->nins++;
+
+ if (COLORED(a) && nfa->parent == NULL) colorchain(nfa->cm, a);
}
/*
* allocarc - allocate a new out-arc within a state
*/
-static struct arc * /* NULL for failure */
-allocarc(struct nfa * nfa,
- struct state * s)
-{
- struct arc *a;
-
- /* shortcut */
- if (s->free == NULL && s->noas < ABSIZE)
- {
- a = &s->oas.a[s->noas];
- s->noas++;
- return a;
- }
-
- /* if none at hand, get more */
- if (s->free == NULL)
- {
- struct arcbatch *newAb;
- int i;
-
- newAb = (struct arcbatch *) MALLOC(sizeof(struct arcbatch));
- if (newAb == NULL)
- {
- NERR(REG_ESPACE);
- return NULL;
- }
- newAb->next = s->oas.next;
- s->oas.next = newAb;
-
- for (i = 0; i < ABSIZE; i++)
- {
- newAb->a[i].type = 0;
- newAb->a[i].freechain = &newAb->a[i + 1];
- }
- newAb->a[ABSIZE - 1].freechain = NULL;
- s->free = &newAb->a[0];
- }
- assert(s->free != NULL);
-
- a = s->free;
- s->free = a->freechain;
- return a;
+static struct arc * /* NULL for failure */
+allocarc(struct nfa *nfa, struct state *s) {
+ struct arc *a;
+
+ /* shortcut */
+ if (s->free == NULL && s->noas < ABSIZE) {
+ a = &s->oas.a[s->noas];
+ s->noas++;
+ return a;
+ }
+
+ /* if none at hand, get more */
+ if (s->free == NULL) {
+ struct arcbatch *newAb;
+ int i;
+
+ newAb = (struct arcbatch *)MALLOC(sizeof(struct arcbatch));
+ if (newAb == NULL) {
+ NERR(REG_ESPACE);
+ return NULL;
+ }
+ newAb->next = s->oas.next;
+ s->oas.next = newAb;
+
+ for (i = 0; i < ABSIZE; i++) {
+ newAb->a[i].type = 0;
+ newAb->a[i].freechain = &newAb->a[i + 1];
+ }
+ newAb->a[ABSIZE - 1].freechain = NULL;
+ s->free = &newAb->a[0];
+ }
+ assert(s->free != NULL);
+
+ a = s->free;
+ s->free = a->freechain;
+ return a;
}
/*
* freearc - free an arc
*/
-static void
-freearc(struct nfa * nfa,
- struct arc * victim)
-{
- struct state *from = victim->from;
- struct state *to = victim->to;
- struct arc *a;
-
- assert(victim->type != 0);
-
- /* take it off color chain if necessary */
- if (COLORED(victim) && nfa->parent == NULL)
- uncolorchain(nfa->cm, victim);
-
- /* take it off source's out-chain */
- assert(from != NULL);
- assert(from->outs != NULL);
- a = from->outs;
- if (a == victim) /* simple case: first in chain */
- from->outs = victim->outchain;
- else
- {
- for (; a != NULL && a->outchain != victim; a = a->outchain)
- continue;
- assert(a != NULL);
- a->outchain = victim->outchain;
- }
- from->nouts--;
-
- /* take it off target's in-chain */
- assert(to != NULL);
- assert(to->ins != NULL);
- a = to->ins;
- if (a == victim) /* simple case: first in chain */
- to->ins = victim->inchain;
- else
- {
- for (; a != NULL && a->inchain != victim; a = a->inchain)
- continue;
- assert(a != NULL);
- a->inchain = victim->inchain;
- }
- to->nins--;
-
- /* clean up and place on free list */
- victim->type = 0;
- victim->from = NULL; /* precautions... */
- victim->to = NULL;
- victim->inchain = NULL;
- victim->outchain = NULL;
- victim->freechain = from->free;
- from->free = victim;
+static void freearc(struct nfa *nfa, struct arc *victim) {
+ struct state *from = victim->from;
+ struct state *to = victim->to;
+ struct arc *a;
+
+ assert(victim->type != 0);
+
+ /* take it off color chain if necessary */
+ if (COLORED(victim) && nfa->parent == NULL) uncolorchain(nfa->cm, victim);
+
+ /* take it off source's out-chain */
+ assert(from != NULL);
+ assert(from->outs != NULL);
+ a = from->outs;
+ if (a == victim) /* simple case: first in chain */
+ from->outs = victim->outchain;
+ else {
+ for (; a != NULL && a->outchain != victim; a = a->outchain) continue;
+ assert(a != NULL);
+ a->outchain = victim->outchain;
+ }
+ from->nouts--;
+
+ /* take it off target's in-chain */
+ assert(to != NULL);
+ assert(to->ins != NULL);
+ a = to->ins;
+ if (a == victim) /* simple case: first in chain */
+ to->ins = victim->inchain;
+ else {
+ for (; a != NULL && a->inchain != victim; a = a->inchain) continue;
+ assert(a != NULL);
+ a->inchain = victim->inchain;
+ }
+ to->nins--;
+
+ /* clean up and place on free list */
+ victim->type = 0;
+ victim->from = NULL; /* precautions... */
+ victim->to = NULL;
+ victim->inchain = NULL;
+ victim->outchain = NULL;
+ victim->freechain = from->free;
+ from->free = victim;
+}
+
+/*
+ * hasnonemptyout - Does state have a non-EMPTY out arc?
+ */
+static int hasnonemptyout(struct state *s) {
+ struct arc *a;
+
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (a->type != EMPTY) return 1;
+ }
+ return 0;
+}
+
+/*
+ * nonemptyouts - count non-EMPTY out arcs of a state
+ */
+static int nonemptyouts(struct state *s) {
+ int n = 0;
+ struct arc *a;
+
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (a->type != EMPTY) n++;
+ }
+ return n;
+}
+
+/*
+ * nonemptyins - count non-EMPTY in arcs of a state
+ */
+static int nonemptyins(struct state *s) {
+ int n = 0;
+ struct arc *a;
+
+ for (a = s->ins; a != NULL; a = a->inchain) {
+ if (a->type != EMPTY) n++;
+ }
+ return n;
}
/*
* findarc - find arc, if any, from given source with given type and color
* If there is more than one such arc, the result is random.
*/
-static struct arc *
-findarc(struct state * s,
- int type,
- pcolor co)
-{
- struct arc *a;
+static struct arc *findarc(struct state *s, int type, pcolor co) {
+ struct arc *a;
- for (a = s->outs; a != NULL; a = a->outchain)
- if (a->type == type && a->co == co)
- return a;
- return NULL;
+ for (a = s->outs; a != NULL; a = a->outchain)
+ if (a->type == type && a->co == co) return a;
+ return NULL;
}
/*
* cparc - allocate a new arc within an NFA, copying details from old one
*/
-static void
-cparc(struct nfa * nfa,
- struct arc * oa,
- struct state * from,
- struct state * to)
-{
- newarc(nfa, oa->type, oa->co, from, to);
+static void cparc(struct nfa *nfa, struct arc *oa, struct state *from,
+ struct state *to) {
+ newarc(nfa, oa->type, oa->co, from, to);
}
/*
@@ -492,91 +457,78 @@ cparc(struct nfa * nfa,
* for duplicate suppression, which makes it easier to just make new
* ones to exploit the suppression built into newarc.
*/
-static void
-moveins(struct nfa * nfa,
- struct state * oldState,
- struct state * newState)
-{
- struct arc *a;
-
- assert(oldState != newState);
-
- while ((a = oldState->ins) != NULL)
- {
- cparc(nfa, a, a->from, newState);
- freearc(nfa, a);
- }
- assert(oldState->nins == 0);
- assert(oldState->ins == NULL);
+static void moveins(struct nfa *nfa, struct state *oldState,
+ struct state *newState) {
+ struct arc *a;
+
+ assert(oldState != newState);
+
+ while ((a = oldState->ins) != NULL) {
+ cparc(nfa, a, a->from, newState);
+ freearc(nfa, a);
+ }
+ assert(oldState->nins == 0);
+ assert(oldState->ins == NULL);
}
/*
- * copyins - copy all in arcs of a state to another state
+ * copyins - copy in arcs of a state to another state
+ *
+ * Either all arcs, or only non-empty ones as determined by all value.
*/
-static void
-copyins(struct nfa * nfa,
- struct state * oldState,
- struct state * newState)
-{
- struct arc *a;
+static void copyins(struct nfa *nfa, struct state *oldState,
+ struct state *newState, int all) {
+ struct arc *a;
- assert(oldState != newState);
+ assert(oldState != newState);
- for (a = oldState->ins; a != NULL; a = a->inchain)
- cparc(nfa, a, a->from, newState);
+ for (a = oldState->ins; a != NULL; a = a->inchain) {
+ if (all || a->type != EMPTY) cparc(nfa, a, a->from, newState);
+ }
}
/*
* moveouts - move all out arcs of a state to another state
*/
-static void
-moveouts(struct nfa * nfa,
- struct state * oldState,
- struct state * newState)
-{
- struct arc *a;
+static void moveouts(struct nfa *nfa, struct state *oldState,
+ struct state *newState) {
+ struct arc *a;
- assert(oldState != newState);
+ assert(oldState != newState);
- while ((a = oldState->outs) != NULL)
- {
- cparc(nfa, a, newState, a->to);
- freearc(nfa, a);
- }
+ while ((a = oldState->outs) != NULL) {
+ cparc(nfa, a, newState, a->to);
+ freearc(nfa, a);
+ }
}
/*
- * copyouts - copy all out arcs of a state to another state
+ * copyouts - copy out arcs of a state to another state
+ *
+ * Either all arcs, or only non-empty ones as determined by all value.
*/
-static void
-copyouts(struct nfa * nfa,
- struct state * oldState,
- struct state * newState)
-{
- struct arc *a;
+static void copyouts(struct nfa *nfa, struct state *oldState,
+ struct state *newState, int all) {
+ struct arc *a;
- assert(oldState != newState);
+ assert(oldState != newState);
- for (a = oldState->outs; a != NULL; a = a->outchain)
- cparc(nfa, a, newState, a->to);
+ for (a = oldState->outs; a != NULL; a = a->outchain) {
+ if (all || a->type != EMPTY) cparc(nfa, a, newState, a->to);
+ }
}
/*
* cloneouts - copy out arcs of a state to another state pair, modifying type
*/
-static void
-cloneouts(struct nfa * nfa,
- struct state * old,
- struct state * from,
- struct state * to,
- int type)
-{
- struct arc *a;
+static void cloneouts(struct nfa *nfa, struct state *old, struct state *from,
+ struct state *to, int type) {
+ struct arc *a;
- assert(old != from);
+ assert(old != from);
- for (a = old->outs; a != NULL; a = a->outchain)
- newarc(nfa, type, a->co, from, to);
+ for (a = old->outs; a != NULL; a = a->outchain)
+ newarc(nfa, type, a->co, from, to);
}
/*
@@ -585,60 +537,52 @@ cloneouts(struct nfa * nfa,
* This uses a recursive traversal of the sub-NFA, marking already-seen
* states using their tmp pointer.
*/
-static void
-delsub(struct nfa * nfa,
- struct state * lp, /* the sub-NFA goes from here... */
- struct state * rp) /* ...to here, *not* inclusive */
+static void delsub(struct nfa *nfa,
+ struct state *lp, /* the sub-NFA goes from here... */
+ struct state *rp) /* ...to here, *not* inclusive */
{
- assert(lp != rp);
+ assert(lp != rp);
- rp->tmp = rp; /* mark end */
+ rp->tmp = rp; /* mark end */
- deltraverse(nfa, lp, lp);
- assert(lp->nouts == 0 && rp->nins == 0); /* did the job */
- assert(lp->no != FREESTATE && rp->no != FREESTATE); /* no more */
+ deltraverse(nfa, lp, lp);
+ assert(lp->nouts == 0 && rp->nins == 0); /* did the job */
+ assert(lp->no != FREESTATE && rp->no != FREESTATE); /* no more */
- rp->tmp = NULL; /* unmark end */
- lp->tmp = NULL; /* and begin, marked by deltraverse */
+ rp->tmp = NULL; /* unmark end */
+ lp->tmp = NULL; /* and begin, marked by deltraverse */
}
/*
* deltraverse - the recursive heart of delsub
* This routine's basic job is to destroy all out-arcs of the state.
*/
-static void
-deltraverse(struct nfa * nfa,
- struct state * leftend,
- struct state * s)
-{
- struct arc *a;
- struct state *to;
-
- if (s->nouts == 0)
- return; /* nothing to do */
- if (s->tmp != NULL)
- return; /* already in progress */
-
- s->tmp = s; /* mark as in progress */
-
- while ((a = s->outs) != NULL)
- {
- to = a->to;
- deltraverse(nfa, leftend, to);
- assert(to->nouts == 0 || to->tmp != NULL);
- freearc(nfa, a);
- if (to->nins == 0 && to->tmp == NULL)
- {
- assert(to->nouts == 0);
- freestate(nfa, to);
- }
- }
-
- assert(s->no != FREESTATE); /* we're still here */
- assert(s == leftend || s->nins != 0); /* and still reachable */
- assert(s->nouts == 0); /* but have no outarcs */
-
- s->tmp = NULL; /* we're done here */
+static void deltraverse(struct nfa *nfa, struct state *leftend,
+ struct state *s) {
+ struct arc *a;
+ struct state *to;
+
+ if (s->nouts == 0) return; /* nothing to do */
+ if (s->tmp != NULL) return; /* already in progress */
+
+ s->tmp = s; /* mark as in progress */
+
+ while ((a = s->outs) != NULL) {
+ to = a->to;
+ deltraverse(nfa, leftend, to);
+ assert(to->nouts == 0 || to->tmp != NULL);
+ freearc(nfa, a);
+ if (to->nins == 0 && to->tmp == NULL) {
+ assert(to->nouts == 0);
+ freestate(nfa, to);
+ }
+ }
+
+ assert(s->no != FREESTATE); /* we're still here */
+ assert(s == leftend || s->nins != 0); /* and still reachable */
+ assert(s->nouts == 0); /* but have no outarcs */
+
+ s->tmp = NULL; /* we're done here */
}
/*
@@ -648,181 +592,147 @@ deltraverse(struct nfa * nfa,
* as well as mark already-seen states. (You knew there was a reason why
* it's a state pointer, didn't you? :-))
*/
-static void
-dupnfa(struct nfa * nfa,
- struct state * start, /* duplicate of subNFA starting here */
- struct state * stop, /* and stopping here */
- struct state * from, /* stringing duplicate from here */
- struct state * to) /* to here */
+static void dupnfa(struct nfa *nfa,
+ struct state *start, /* duplicate of subNFA starting here */
+ struct state *stop, /* and stopping here */
+ struct state *from, /* stringing duplicate from here */
+ struct state *to) /* to here */
{
- if (start == stop)
- {
- newarc(nfa, EMPTY, 0, from, to);
- return;
- }
-
- stop->tmp = to;
- duptraverse(nfa, start, from);
- /* done, except for clearing out the tmp pointers */
-
- stop->tmp = NULL;
- cleartraverse(nfa, start);
+ if (start == stop) {
+ newarc(nfa, EMPTY, 0, from, to);
+ return;
+ }
+
+ stop->tmp = to;
+ duptraverse(nfa, start, from);
+ /* done, except for clearing out the tmp pointers */
+
+ stop->tmp = NULL;
+ cleartraverse(nfa, start);
}
/*
* duptraverse - recursive heart of dupnfa
*/
-static void
-duptraverse(struct nfa * nfa,
- struct state * s,
- struct state * stmp) /* s's duplicate, or NULL */
+static void duptraverse(struct nfa *nfa, struct state *s,
+ struct state *stmp) /* s's duplicate, or NULL */
{
- struct arc *a;
-
- if (s->tmp != NULL)
- return; /* already done */
-
- s->tmp = (stmp == NULL) ? newstate(nfa) : stmp;
- if (s->tmp == NULL)
- {
- assert(NISERR());
- return;
- }
-
- for (a = s->outs; a != NULL && !NISERR(); a = a->outchain)
- {
- duptraverse(nfa, a->to, (struct state *) NULL);
- if (NISERR())
- break;
- assert(a->to->tmp != NULL);
- cparc(nfa, a, s->tmp, a->to->tmp);
- }
+ struct arc *a;
+
+ if (s->tmp != NULL) return; /* already done */
+
+ s->tmp = (stmp == NULL) ? newstate(nfa) : stmp;
+ if (s->tmp == NULL) {
+ assert(NISERR());
+ return;
+ }
+
+ for (a = s->outs; a != NULL && !NISERR(); a = a->outchain) {
+ duptraverse(nfa, a->to, (struct state *)NULL);
+ if (NISERR()) break;
+ assert(a->to->tmp != NULL);
+ cparc(nfa, a, s->tmp, a->to->tmp);
+ }
}
/*
* cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set
*/
-static void
-cleartraverse(struct nfa * nfa,
- struct state * s)
-{
- struct arc *a;
+static void cleartraverse(struct nfa *nfa, struct state *s) {
+ struct arc *a;
- if (s->tmp == NULL)
- return;
- s->tmp = NULL;
+ if (s->tmp == NULL) return;
+ s->tmp = NULL;
- for (a = s->outs; a != NULL; a = a->outchain)
- cleartraverse(nfa, a->to);
+ for (a = s->outs; a != NULL; a = a->outchain) cleartraverse(nfa, a->to);
}
/*
* specialcolors - fill in special colors for an NFA
*/
-static void
-specialcolors(struct nfa * nfa)
-{
- /* false colors for BOS, BOL, EOS, EOL */
- if (nfa->parent == NULL)
- {
- nfa->bos[0] = pseudocolor(nfa->cm);
- nfa->bos[1] = pseudocolor(nfa->cm);
- nfa->eos[0] = pseudocolor(nfa->cm);
- nfa->eos[1] = pseudocolor(nfa->cm);
- }
- else
- {
- assert(nfa->parent->bos[0] != COLORLESS);
- nfa->bos[0] = nfa->parent->bos[0];
- assert(nfa->parent->bos[1] != COLORLESS);
- nfa->bos[1] = nfa->parent->bos[1];
- assert(nfa->parent->eos[0] != COLORLESS);
- nfa->eos[0] = nfa->parent->eos[0];
- assert(nfa->parent->eos[1] != COLORLESS);
- nfa->eos[1] = nfa->parent->eos[1];
- }
+static void specialcolors(struct nfa *nfa) {
+ /* false colors for BOS, BOL, EOS, EOL */
+ if (nfa->parent == NULL) {
+ nfa->bos[0] = pseudocolor(nfa->cm);
+ nfa->bos[1] = pseudocolor(nfa->cm);
+ nfa->eos[0] = pseudocolor(nfa->cm);
+ nfa->eos[1] = pseudocolor(nfa->cm);
+ } else {
+ assert(nfa->parent->bos[0] != COLORLESS);
+ nfa->bos[0] = nfa->parent->bos[0];
+ assert(nfa->parent->bos[1] != COLORLESS);
+ nfa->bos[1] = nfa->parent->bos[1];
+ assert(nfa->parent->eos[0] != COLORLESS);
+ nfa->eos[0] = nfa->parent->eos[0];
+ assert(nfa->parent->eos[1] != COLORLESS);
+ nfa->eos[1] = nfa->parent->eos[1];
+ }
}
/*
* optimize - optimize an NFA
*/
-static long /* re_info bits */
-optimize(struct nfa * nfa,
- FILE *f) /* for debug output; NULL none */
+static long /* re_info bits */
+optimize(struct nfa *nfa, FILE *f) /* for debug output; NULL none */
{
#ifdef REG_DEBUG
- int verbose = (f != NULL) ? 1 : 0;
+ int verbose = (f != NULL) ? 1 : 0;
- if (verbose)
- fprintf(f, "\ninitial cleanup:\n");
+ if (verbose) fprintf(f, "\ninitial cleanup:\n");
#endif
- cleanup(nfa); /* may simplify situation */
+ cleanup(nfa); /* may simplify situation */
#ifdef REG_DEBUG
- if (verbose)
- dumpnfa(nfa, f);
- if (verbose)
- fprintf(f, "\nempties:\n");
+ if (verbose) dumpnfa(nfa, f);
+ if (verbose) fprintf(f, "\nempties:\n");
#endif
- fixempties(nfa, f); /* get rid of EMPTY arcs */
+ fixempties(nfa, f); /* get rid of EMPTY arcs */
#ifdef REG_DEBUG
- if (verbose)
- fprintf(f, "\nconstraints:\n");
+ if (verbose) fprintf(f, "\nconstraints:\n");
#endif
- pullback(nfa, f); /* pull back constraints backward */
- pushfwd(nfa, f); /* push fwd constraints forward */
+ pullback(nfa, f); /* pull back constraints backward */
+ pushfwd(nfa, f); /* push fwd constraints forward */
#ifdef REG_DEBUG
- if (verbose)
- fprintf(f, "\nfinal cleanup:\n");
+ if (verbose) fprintf(f, "\nfinal cleanup:\n");
#endif
- cleanup(nfa); /* final tidying */
- return analyze(nfa); /* and analysis */
+ cleanup(nfa); /* final tidying */
+ return analyze(nfa); /* and analysis */
}
/*
* pullback - pull back constraints backward to (with luck) eliminate them
*/
-static void
-pullback(struct nfa * nfa,
- FILE *f) /* for debug output; NULL none */
+static void pullback(struct nfa *nfa, FILE *f) /* for debug output; NULL none */
{
- struct state *s;
- struct state *nexts;
- struct arc *a;
- struct arc *nexta;
- int progress;
-
- /* find and pull until there are no more */
- do
- {
- progress = 0;
- for (s = nfa->states; s != NULL && !NISERR(); s = nexts)
- {
- nexts = s->next;
- for (a = s->outs; a != NULL && !NISERR(); a = nexta)
- {
- nexta = a->outchain;
- if (a->type == '^' || a->type == BEHIND)
- if (pull(nfa, a))
- progress = 1;
- assert(nexta == NULL || s->no != FREESTATE);
- }
- }
- if (progress && f != NULL)
- dumpnfa(nfa, f);
- } while (progress && !NISERR());
- if (NISERR())
- return;
-
- for (a = nfa->pre->outs; a != NULL; a = nexta)
- {
- nexta = a->outchain;
- if (a->type == '^')
- {
- assert(a->co == 0 || a->co == 1);
- newarc(nfa, PLAIN, nfa->bos[a->co], a->from, a->to);
- freearc(nfa, a);
- }
- }
+ struct state *s;
+ struct state *nexts;
+ struct arc *a;
+ struct arc *nexta;
+ int progress;
+
+ /* find and pull until there are no more */
+ do {
+ progress = 0;
+ for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
+ nexts = s->next;
+ for (a = s->outs; a != NULL && !NISERR(); a = nexta) {
+ nexta = a->outchain;
+ if (a->type == '^' || a->type == BEHIND)
+ if (pull(nfa, a)) progress = 1;
+ assert(nexta == NULL || s->no != FREESTATE);
+ }
+ }
+ if (progress && f != NULL) dumpnfa(nfa, f);
+ } while (progress && !NISERR());
+ if (NISERR()) return;
+
+ for (a = nfa->pre->outs; a != NULL; a = nexta) {
+ nexta = a->outchain;
+ if (a->type == '^') {
+ assert(a->co == 0 || a->co == 1);
+ newarc(nfa, PLAIN, nfa->bos[a->co], a->from, a->to);
+ freearc(nfa, a);
+ }
+ }
}
/*
@@ -831,142 +741,119 @@ pullback(struct nfa * nfa,
* one state -- the constraint's from state -- and only if the constraint
* was that state's last outarc.
*/
-static int /* 0 couldn't, 1 could */
-pull(struct nfa * nfa,
- struct arc * con)
-{
- struct state *from = con->from;
- struct state *to = con->to;
- struct arc *a;
- struct arc *nexta;
- struct state *s;
-
- if (from == to)
- { /* circular constraint is pointless */
- freearc(nfa, con);
- return 1;
- }
- if (from->flag) /* can't pull back beyond start */
- return 0;
- if (from->nins == 0)
- { /* unreachable */
- freearc(nfa, con);
- return 1;
- }
-
- /*
- * DGP 2007-11-15: Cloning a state with a circular constraint on its list
- * of outs can lead to trouble [Tcl Bug 1810038], so get rid of them
- * first.
- */
- for (a = from->outs; a != NULL; a = nexta)
- {
- nexta = a->outchain;
- switch (a->type)
- {
- case '^':
- case '$':
- case BEHIND:
- case AHEAD:
- if (from == a->to)
- freearc(nfa, a);
- break;
- }
- }
-
- /* first, clone from state if necessary to avoid other outarcs */
- if (from->nouts > 1)
- {
- s = newstate(nfa);
- if (NISERR())
- return 0;
- assert(to != from); /* con is not an inarc */
- copyins(nfa, from, s); /* duplicate inarcs */
- cparc(nfa, con, s, to); /* move constraint arc */
- freearc(nfa, con);
- from = s;
- con = from->outs;
- }
- assert(from->nouts == 1);
-
- /* propagate the constraint into the from state's inarcs */
- for (a = from->ins; a != NULL; a = nexta)
- {
- nexta = a->inchain;
- switch (combine(con, a))
- {
- case INCOMPATIBLE: /* destroy the arc */
- freearc(nfa, a);
- break;
- case SATISFIED: /* no action needed */
- break;
- case COMPATIBLE: /* swap the two arcs, more or less */
- s = newstate(nfa);
- if (NISERR())
- return 0;
- cparc(nfa, a, s, to); /* anticipate move */
- cparc(nfa, con, a->from, s);
- if (NISERR())
- return 0;
- freearc(nfa, a);
- break;
- default:
- assert(NOTREACHED);
- break;
- }
- }
-
- /* remaining inarcs, if any, incorporate the constraint */
- moveins(nfa, from, to);
- dropstate(nfa, from); /* will free the constraint */
- return 1;
+static int /* 0 couldn't, 1 could */
+pull(struct nfa *nfa, struct arc *con) {
+ struct state *from = con->from;
+ struct state *to = con->to;
+ struct arc *a;
+ struct arc *nexta;
+ struct state *s;
+
+ if (from == to) { /* circular constraint is pointless */
+ freearc(nfa, con);
+ return 1;
+ }
+ if (from->flag) /* can't pull back beyond start */
+ return 0;
+ if (from->nins == 0) { /* unreachable */
+ freearc(nfa, con);
+ return 1;
+ }
+
+ /*
+ * DGP 2007-11-15: Cloning a state with a circular constraint on its list
+ * of outs can lead to trouble [Tcl Bug 1810038], so get rid of them
+ * first.
+ */
+ for (a = from->outs; a != NULL; a = nexta) {
+ nexta = a->outchain;
+ switch (a->type) {
+ case '^':
+ case '$':
+ case BEHIND:
+ case AHEAD:
+ if (from == a->to) freearc(nfa, a);
+ break;
+ }
+ }
+
+ /* first, clone from state if necessary to avoid other outarcs */
+ if (from->nouts > 1) {
+ s = newstate(nfa);
+ if (NISERR()) return 0;
+ assert(to != from); /* con is not an inarc */
+ copyins(nfa, from, s, 1); /* duplicate inarcs */
+ cparc(nfa, con, s, to); /* move constraint arc */
+ freearc(nfa, con);
+ from = s;
+ con = from->outs;
+ }
+ assert(from->nouts == 1);
+
+ /* propagate the constraint into the from state's inarcs */
+ for (a = from->ins; a != NULL; a = nexta) {
+ nexta = a->inchain;
+ switch (combine(con, a)) {
+ case INCOMPATIBLE: /* destroy the arc */
+ freearc(nfa, a);
+ break;
+ case SATISFIED: /* no action needed */
+ break;
+ case COMPATIBLE: /* swap the two arcs, more or less */
+ s = newstate(nfa);
+ if (NISERR()) return 0;
+ cparc(nfa, a, s, to); /* anticipate move */
+ cparc(nfa, con, a->from, s);
+ if (NISERR()) return 0;
+ freearc(nfa, a);
+ break;
+ default:
+ assert(NOTREACHED);
+ break;
+ }
+ }
+
+ /* remaining inarcs, if any, incorporate the constraint */
+ moveins(nfa, from, to);
+ dropstate(nfa, from); /* will free the constraint */
+ return 1;
}
/*
* pushfwd - push forward constraints forward to (with luck) eliminate them
*/
-static void
-pushfwd(struct nfa * nfa,
- FILE *f) /* for debug output; NULL none */
+static void pushfwd(struct nfa *nfa, FILE *f) /* for debug output; NULL none */
{
- struct state *s;
- struct state *nexts;
- struct arc *a;
- struct arc *nexta;
- int progress;
-
- /* find and push until there are no more */
- do
- {
- progress = 0;
- for (s = nfa->states; s != NULL && !NISERR(); s = nexts)
- {
- nexts = s->next;
- for (a = s->ins; a != NULL && !NISERR(); a = nexta)
- {
- nexta = a->inchain;
- if (a->type == '$' || a->type == AHEAD)
- if (push(nfa, a))
- progress = 1;
- assert(nexta == NULL || s->no != FREESTATE);
- }
- }
- if (progress && f != NULL)
- dumpnfa(nfa, f);
- } while (progress && !NISERR());
- if (NISERR())
- return;
-
- for (a = nfa->post->ins; a != NULL; a = nexta)
- {
- nexta = a->inchain;
- if (a->type == '$')
- {
- assert(a->co == 0 || a->co == 1);
- newarc(nfa, PLAIN, nfa->eos[a->co], a->from, a->to);
- freearc(nfa, a);
- }
- }
+ struct state *s;
+ struct state *nexts;
+ struct arc *a;
+ struct arc *nexta;
+ int progress;
+
+ /* find and push until there are no more */
+ do {
+ progress = 0;
+ for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
+ nexts = s->next;
+ for (a = s->ins; a != NULL && !NISERR(); a = nexta) {
+ nexta = a->inchain;
+ if (a->type == '$' || a->type == AHEAD)
+ if (push(nfa, a)) progress = 1;
+ assert(nexta == NULL || s->no != FREESTATE);
+ }
+ }
+ if (progress && f != NULL) dumpnfa(nfa, f);
+ } while (progress && !NISERR());
+ if (NISERR()) return;
+
+ for (a = nfa->post->ins; a != NULL; a = nexta) {
+ nexta = a->inchain;
+ if (a->type == '$') {
+ assert(a->co == 0 || a->co == 1);
+ newarc(nfa, PLAIN, nfa->eos[a->co], a->from, a->to);
+ freearc(nfa, a);
+ }
+ }
}
/*
@@ -975,97 +862,84 @@ pushfwd(struct nfa * nfa,
* one state -- the constraint's to state -- and only if the constraint
* was that state's last inarc.
*/
-static int /* 0 couldn't, 1 could */
-push(struct nfa * nfa,
- struct arc * con)
-{
- struct state *from = con->from;
- struct state *to = con->to;
- struct arc *a;
- struct arc *nexta;
- struct state *s;
-
- if (to == from)
- { /* circular constraint is pointless */
- freearc(nfa, con);
- return 1;
- }
- if (to->flag) /* can't push forward beyond end */
- return 0;
- if (to->nouts == 0)
- { /* dead end */
- freearc(nfa, con);
- return 1;
- }
-
- /*
- * DGP 2007-11-15: Here we duplicate the same protections as appear in
- * pull() above to avoid troubles with cloning a state with a circular
- * constraint on its list of ins. It is not clear whether this is
- * necessary, or is protecting against a "can't happen". Any test case
- * that actually leads to a freearc() call here would be a welcome
- * addition to the test suite.
- */
- for (a = to->ins; a != NULL; a = nexta)
- {
- nexta = a->inchain;
- switch (a->type)
- {
- case '^':
- case '$':
- case BEHIND:
- case AHEAD:
- if (a->from == to)
- freearc(nfa, a);
- break;
- }
- }
-
- /* first, clone to state if necessary to avoid other inarcs */
- if (to->nins > 1)
- {
- s = newstate(nfa);
- if (NISERR())
- return 0;
- copyouts(nfa, to, s); /* duplicate outarcs */
- cparc(nfa, con, from, s); /* move constraint */
- freearc(nfa, con);
- to = s;
- con = to->ins;
- }
- assert(to->nins == 1);
-
- /* propagate the constraint into the to state's outarcs */
- for (a = to->outs; a != NULL; a = nexta)
- {
- nexta = a->outchain;
- switch (combine(con, a))
- {
- case INCOMPATIBLE: /* destroy the arc */
- freearc(nfa, a);
- break;
- case SATISFIED: /* no action needed */
- break;
- case COMPATIBLE: /* swap the two arcs, more or less */
- s = newstate(nfa);
- if (NISERR())
- return 0;
- cparc(nfa, con, s, a->to); /* anticipate move */
- cparc(nfa, a, from, s);
- if (NISERR())
- return 0;
- freearc(nfa, a);
- break;
- default:
- assert(NOTREACHED);
- break;
- }
- }
-
- /* remaining outarcs, if any, incorporate the constraint */
- moveouts(nfa, to, from);
- dropstate(nfa, to); /* will free the constraint */
- return 1;
+static int /* 0 couldn't, 1 could */
+push(struct nfa *nfa, struct arc *con) {
+ struct state *from = con->from;
+ struct state *to = con->to;
+ struct arc *a;
+ struct arc *nexta;
+ struct state *s;
+
+ if (to == from) { /* circular constraint is pointless */
+ freearc(nfa, con);
+ return 1;
+ }
+ if (to->flag) /* can't push forward beyond end */
+ return 0;
+ if (to->nouts == 0) { /* dead end */
+ freearc(nfa, con);
+ return 1;
+ }
+
+ /*
+ * DGP 2007-11-15: Here we duplicate the same protections as appear in
+ * pull() above to avoid troubles with cloning a state with a circular
+ * constraint on its list of ins. It is not clear whether this is
+ * necessary, or is protecting against a "can't happen". Any test case
+ * that actually leads to a freearc() call here would be a welcome
+ * addition to the test suite.
+ */
+ for (a = to->ins; a != NULL; a = nexta) {
+ nexta = a->inchain;
+ switch (a->type) {
+ case '^':
+ case '$':
+ case BEHIND:
+ case AHEAD:
+ if (a->from == to) freearc(nfa, a);
+ break;
+ }
+ }
+
+ /* first, clone to state if necessary to avoid other inarcs */
+ if (to->nins > 1) {
+ s = newstate(nfa);
+ if (NISERR()) return 0;
+ copyouts(nfa, to, s, 1); /* duplicate outarcs */
+ cparc(nfa, con, from, s); /* move constraint */
+ freearc(nfa, con);
+ to = s;
+ con = to->ins;
+ }
+ assert(to->nins == 1);
+
+ /* propagate the constraint into the to state's outarcs */
+ for (a = to->outs; a != NULL; a = nexta) {
+ nexta = a->outchain;
+ switch (combine(con, a)) {
+ case INCOMPATIBLE: /* destroy the arc */
+ freearc(nfa, a);
+ break;
+ case SATISFIED: /* no action needed */
+ break;
+ case COMPATIBLE: /* swap the two arcs, more or less */
+ s = newstate(nfa);
+ if (NISERR()) return 0;
+ cparc(nfa, con, s, a->to); /* anticipate move */
+ cparc(nfa, a, from, s);
+ if (NISERR()) return 0;
+ freearc(nfa, a);
+ break;
+ default:
+ assert(NOTREACHED);
+ break;
+ }
+ }
+
+ /* remaining outarcs, if any, incorporate the constraint */
+ moveouts(nfa, to, from);
+ dropstate(nfa, to); /* will free the constraint */
+ return 1;
}
/*
@@ -1075,325 +949,383 @@ push(struct nfa * nfa,
* #def SATISFIED 2 // constraint satisfied
* #def COMPATIBLE 3 // compatible but not satisfied yet
*/
-static int
-combine(struct arc * con,
- struct arc * a)
-{
-#define CA(ct,at) (((ct)<<CHAR_BIT) | (at))
-
- switch (CA(con->type, a->type))
- {
- case CA('^', PLAIN): /* newlines are handled separately */
- case CA('$', PLAIN):
- return INCOMPATIBLE;
- break;
- case CA(AHEAD, PLAIN): /* color constraints meet colors */
- case CA(BEHIND, PLAIN):
- if (con->co == a->co)
- return SATISFIED;
- return INCOMPATIBLE;
- break;
- case CA('^', '^'): /* collision, similar constraints */
- case CA('$', '$'):
- case CA(AHEAD, AHEAD):
- case CA(BEHIND, BEHIND):
- if (con->co == a->co) /* true duplication */
- return SATISFIED;
- return INCOMPATIBLE;
- break;
- case CA('^', BEHIND): /* collision, dissimilar constraints */
- case CA(BEHIND, '^'):
- case CA('$', AHEAD):
- case CA(AHEAD, '$'):
- return INCOMPATIBLE;
- break;
- case CA('^', '$'): /* constraints passing each other */
- case CA('^', AHEAD):
- case CA(BEHIND, '$'):
- case CA(BEHIND, AHEAD):
- case CA('$', '^'):
- case CA('$', BEHIND):
- case CA(AHEAD, '^'):
- case CA(AHEAD, BEHIND):
- case CA('^', LACON):
- case CA(BEHIND, LACON):
- case CA('$', LACON):
- case CA(AHEAD, LACON):
- return COMPATIBLE;
- break;
- }
- assert(NOTREACHED);
- return INCOMPATIBLE; /* for benefit of blind compilers */
+static int combine(struct arc *con, struct arc *a) {
+#define CA(ct, at) (((ct) << CHAR_BIT) | (at))
+
+ switch (CA(con->type, a->type)) {
+ case CA('^', PLAIN): /* newlines are handled separately */
+ case CA('$', PLAIN):
+ return INCOMPATIBLE;
+ break;
+ case CA(AHEAD, PLAIN): /* color constraints meet colors */
+ case CA(BEHIND, PLAIN):
+ if (con->co == a->co) return SATISFIED;
+ return INCOMPATIBLE;
+ break;
+ case CA('^', '^'): /* collision, similar constraints */
+ case CA('$', '$'):
+ case CA(AHEAD, AHEAD):
+ case CA(BEHIND, BEHIND):
+ if (con->co == a->co) /* true duplication */
+ return SATISFIED;
+ return INCOMPATIBLE;
+ break;
+ case CA('^', BEHIND): /* collision, dissimilar constraints */
+ case CA(BEHIND, '^'):
+ case CA('$', AHEAD):
+ case CA(AHEAD, '$'):
+ return INCOMPATIBLE;
+ break;
+ case CA('^', '$'): /* constraints passing each other */
+ case CA('^', AHEAD):
+ case CA(BEHIND, '$'):
+ case CA(BEHIND, AHEAD):
+ case CA('$', '^'):
+ case CA('$', BEHIND):
+ case CA(AHEAD, '^'):
+ case CA(AHEAD, BEHIND):
+ case CA('^', LACON):
+ case CA(BEHIND, LACON):
+ case CA('$', LACON):
+ case CA(AHEAD, LACON):
+ return COMPATIBLE;
+ break;
+ }
+ assert(NOTREACHED);
+ return INCOMPATIBLE; /* for benefit of blind compilers */
}
/*
* fixempties - get rid of EMPTY arcs
*/
-static void
-fixempties(struct nfa * nfa,
- FILE *f) /* for debug output; NULL none */
+static void fixempties(struct nfa *nfa,
+ FILE *f) /* for debug output; NULL none */
{
- struct state *s;
- struct state *nexts;
- struct arc *a;
- struct arc *nexta;
- int progress;
-
- /* find and eliminate empties until there are no more */
- do
- {
- progress = 0;
- for (s = nfa->states; s != NULL && !NISERR() &&
- s->no != FREESTATE; s = nexts)
- {
- nexts = s->next;
- for (a = s->outs; a != NULL && !NISERR(); a = nexta)
- {
- nexta = a->outchain;
- if (a->type == EMPTY && unempty(nfa, a))
- progress = 1;
- assert(nexta == NULL || s->no != FREESTATE);
- }
- }
- if (progress && f != NULL)
- dumpnfa(nfa, f);
- } while (progress && !NISERR());
+ struct state *s;
+ struct state *s2;
+ struct state *nexts;
+ struct arc *a;
+ struct arc *nexta;
+
+ /*
+ * First, get rid of any states whose sole out-arc is an EMPTY, since
+ * they're basically just aliases for their successor. The parsing
+ * algorithm creates enough of these that it's worth special-casing this.
+ */
+ for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
+ nexts = s->next;
+ if (s->flag || s->nouts != 1) continue;
+ a = s->outs;
+ assert(a != NULL && a->outchain == NULL);
+ if (a->type != EMPTY) continue;
+ if (s != a->to) moveins(nfa, s, a->to);
+ dropstate(nfa, s);
+ }
+
+ /*
+ * Similarly, get rid of any state with a single EMPTY in-arc, by folding
+ * it into its predecessor.
+ */
+ for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
+ nexts = s->next;
+ /* while we're at it, ensure tmp fields are clear for next step */
+ assert(s->tmp == NULL);
+ if (s->flag || s->nins != 1) continue;
+ a = s->ins;
+ assert(a != NULL && a->inchain == NULL);
+ if (a->type != EMPTY) continue;
+ if (s != a->from) moveouts(nfa, s, a->from);
+ dropstate(nfa, s);
+ }
+
+ /*
+ * For each remaining NFA state, find all other states that are reachable
+ * from it by a chain of one or more EMPTY arcs. Then generate new arcs
+ * that eliminate the need for each such chain.
+ *
+ * If we just do this straightforwardly, the algorithm gets slow in
+ * complex graphs, because the same arcs get copied to all intermediate
+ * states of an EMPTY chain, and then uselessly pushed repeatedly to the
+ * chain's final state; we waste a lot of time in newarc's duplicate
+ * checking. To improve matters, we decree that any state with only EMPTY
+ * out-arcs is "doomed" and will not be part of the final NFA. That can be
+ * ensured by not adding any new out-arcs to such a state. Having ensured
+ * that, we need not update the state's in-arcs list either; all arcs that
+ * might have gotten pushed forward to it will just get pushed directly to
+ * successor states. This eliminates most of the useless duplicate arcs.
+ */
+ for (s = nfa->states; s != NULL && !NISERR(); s = s->next) {
+ for (s2 = emptyreachable(s, s); s2 != s && !NISERR(); s2 = nexts) {
+ /*
+ * If s2 is doomed, we decide that (1) we will always push arcs
+ * forward to it, not pull them back to s; and (2) we can optimize
+ * away the push-forward, per comment above. So do nothing.
+ */
+ if (s2->flag || hasnonemptyout(s2)) replaceempty(nfa, s, s2);
+
+ /* Reset the tmp fields as we walk back */
+ nexts = s2->tmp;
+ s2->tmp = NULL;
+ }
+ s->tmp = NULL;
+ }
+
+ if (NISERR()) return;
+
+ /*
+ * Now remove all the EMPTY arcs, since we don't need them anymore.
+ */
+ for (s = nfa->states; s != NULL; s = s->next) {
+ for (a = s->outs; a != NULL; a = nexta) {
+ nexta = a->outchain;
+ if (a->type == EMPTY) freearc(nfa, a);
+ }
+ }
+
+ /*
+ * And remove any states that have become useless. (This cleanup is not
+ * very thorough, and would be even less so if we tried to combine it with
+ * the previous step; but cleanup() will take care of anything we miss.)
+ */
+ for (s = nfa->states; s != NULL; s = nexts) {
+ nexts = s->next;
+ if ((s->nins == 0 || s->nouts == 0) && !s->flag) dropstate(nfa, s);
+ }
+
+ if (f != NULL) dumpnfa(nfa, f);
}
/*
- * unempty - optimize out an EMPTY arc, if possible
+ * emptyreachable - recursively find all states reachable from s by EMPTY arcs
+ *
+ * The return value is the last such state found. Its tmp field links back
+ * to the next-to-last such state, and so on back to s, so that all these
+ * states can be located without searching the whole NFA.
*
- * Actually, as it stands this function always succeeds, but the return
- * value is kept with an eye on possible future changes.
+ * The maximum recursion depth here is equal to the length of the longest
+ * loop-free chain of EMPTY arcs, which is surely no more than the size of
+ * the NFA, and in practice will be a lot less than that.
*/
-static int /* 0 couldn't, 1 could */
-unempty(struct nfa * nfa,
- struct arc * a)
-{
- struct state *from = a->from;
- struct state *to = a->to;
- int usefrom; /* work on from, as opposed to to? */
-
- assert(a->type == EMPTY);
- assert(from != nfa->pre && to != nfa->post);
-
- if (from == to)
- { /* vacuous loop */
- freearc(nfa, a);
- return 1;
- }
-
- /* decide which end to work on */
- usefrom = 1; /* default: attack from */
- if (from->nouts > to->nins)
- usefrom = 0;
- else if (from->nouts == to->nins)
- {
- /* decide on secondary issue: move/copy fewest arcs */
- if (from->nins > to->nouts)
- usefrom = 0;
- }
-
- freearc(nfa, a);
- if (usefrom)
- {
- if (from->nouts == 0)
- {
- /* was the state's only outarc */
- moveins(nfa, from, to);
- freestate(nfa, from);
- }
- else
- copyins(nfa, from, to);
- }
- else
- {
- if (to->nins == 0)
- {
- /* was the state's only inarc */
- moveouts(nfa, to, from);
- freestate(nfa, to);
- }
- else
- copyouts(nfa, to, from);
- }
-
- return 1;
+static struct state *emptyreachable(struct state *s, struct state *lastfound) {
+ struct arc *a;
+
+ s->tmp = lastfound;
+ lastfound = s;
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (a->type == EMPTY && a->to->tmp == NULL)
+ lastfound = emptyreachable(a->to, lastfound);
+ }
+ return lastfound;
+}
+
+/*
+ * replaceempty - replace an EMPTY arc chain with some non-empty arcs
+ *
+ * The EMPTY arc(s) should be deleted later, but we can't do it here because
+ * they may still be needed to identify other arc chains during fixempties().
+ */
+static void replaceempty(struct nfa *nfa, struct state *from,
+ struct state *to) {
+ int fromouts;
+ int toins;
+
+ assert(from != to);
+
+ /*
+ * Create replacement arcs that bypass the need for the EMPTY chain. We
+ * can do this either by pushing arcs forward (linking directly from
+ * "from"'s predecessors to "to") or by pulling them back (linking
+ * directly from "from" to "to"'s successors). In general, we choose
+ * whichever way creates greater fan-out or fan-in, so as to improve the
+ * odds of reducing the other state to zero in-arcs or out-arcs and
+ * thereby being able to delete it. However, if "from" is doomed (has no
+ * non-EMPTY out-arcs), we must keep it so, so always push forward in that
+ * case.
+ *
+ * The fan-out/fan-in comparison should count only non-EMPTY arcs. If
+ * "from" is doomed, we can skip counting "to"'s arcs, since we want to
+ * force taking the copyins path in that case.
+ */
+ fromouts = nonemptyouts(from);
+ toins = (fromouts == 0) ? 1 : nonemptyins(to);
+
+ if (fromouts > toins) {
+ copyouts(nfa, to, from, 0);
+ return;
+ }
+
+ if (fromouts < toins) {
+ copyins(nfa, from, to, 0);
+ return;
+ }
+
+ /*
+ * fromouts == toins. Decide on secondary issue: copy fewest arcs.
+ *
+ * Doesn't seem to be worth the trouble to exclude empties from these
+ * comparisons; that takes extra time and doesn't seem to improve the
+ * resulting graph much.
+ */
+ if (from->nins > to->nouts) {
+ copyouts(nfa, to, from, 0);
+ return;
+ } else {
+ copyins(nfa, from, to, 0);
+ return;
+ }
}
/*
* cleanup - clean up NFA after optimizations
*/
-static void
-cleanup(struct nfa * nfa)
-{
- struct state *s;
- struct state *nexts;
- int n;
-
- /* clear out unreachable or dead-end states */
- /* use pre to mark reachable, then post to mark can-reach-post */
- markreachable(nfa, nfa->pre, (struct state *) NULL, nfa->pre);
- markcanreach(nfa, nfa->post, nfa->pre, nfa->post);
- for (s = nfa->states; s != NULL; s = nexts)
- {
- nexts = s->next;
- if (s->tmp != nfa->post && !s->flag)
- dropstate(nfa, s);
- }
- assert(nfa->post->nins == 0 || nfa->post->tmp == nfa->post);
- cleartraverse(nfa, nfa->pre);
- assert(nfa->post->nins == 0 || nfa->post->tmp == NULL);
- /* the nins==0 (final unreachable) case will be caught later */
-
- /* renumber surviving states */
- n = 0;
- for (s = nfa->states; s != NULL; s = s->next)
- s->no = n++;
- nfa->nstates = n;
+static void cleanup(struct nfa *nfa) {
+ struct state *s;
+ struct state *nexts;
+ int n;
+
+ /* clear out unreachable or dead-end states */
+ /* use pre to mark reachable, then post to mark can-reach-post */
+ markreachable(nfa, nfa->pre, (struct state *)NULL, nfa->pre);
+ markcanreach(nfa, nfa->post, nfa->pre, nfa->post);
+ for (s = nfa->states; s != NULL; s = nexts) {
+ nexts = s->next;
+ if (s->tmp != nfa->post && !s->flag) dropstate(nfa, s);
+ }
+ assert(nfa->post->nins == 0 || nfa->post->tmp == nfa->post);
+ cleartraverse(nfa, nfa->pre);
+ assert(nfa->post->nins == 0 || nfa->post->tmp == NULL);
+ /* the nins==0 (final unreachable) case will be caught later */
+
+ /* renumber surviving states */
+ n = 0;
+ for (s = nfa->states; s != NULL; s = s->next) s->no = n++;
+ nfa->nstates = n;
}
/*
* markreachable - recursive marking of reachable states
*/
-static void
-markreachable(struct nfa * nfa,
- struct state * s,
- struct state * okay, /* consider only states with this mark */
- struct state * mark) /* the value to mark with */
+static void markreachable(
+ struct nfa *nfa, struct state *s,
+ struct state *okay, /* consider only states with this mark */
+ struct state *mark) /* the value to mark with */
{
- struct arc *a;
+ struct arc *a;
- if (s->tmp != okay)
- return;
- s->tmp = mark;
+ if (s->tmp != okay) return;
+ s->tmp = mark;
- for (a = s->outs; a != NULL; a = a->outchain)
- markreachable(nfa, a->to, okay, mark);
+ for (a = s->outs; a != NULL; a = a->outchain)
+ markreachable(nfa, a->to, okay, mark);
}
/*
* markcanreach - recursive marking of states which can reach here
*/
-static void
-markcanreach(struct nfa * nfa,
- struct state * s,
- struct state * okay, /* consider only states with this mark */
- struct state * mark) /* the value to mark with */
+static void markcanreach(
+ struct nfa *nfa, struct state *s,
+ struct state *okay, /* consider only states with this mark */
+ struct state *mark) /* the value to mark with */
{
- struct arc *a;
+ struct arc *a;
- if (s->tmp != okay)
- return;
- s->tmp = mark;
+ if (s->tmp != okay) return;
+ s->tmp = mark;
- for (a = s->ins; a != NULL; a = a->inchain)
- markcanreach(nfa, a->from, okay, mark);
+ for (a = s->ins; a != NULL; a = a->inchain)
+ markcanreach(nfa, a->from, okay, mark);
}
/*
* analyze - ascertain potentially-useful facts about an optimized NFA
*/
-static long /* re_info bits to be ORed in */
-analyze(struct nfa * nfa)
-{
- struct arc *a;
- struct arc *aa;
-
- if (nfa->pre->outs == NULL)
- return REG_UIMPOSSIBLE;
- for (a = nfa->pre->outs; a != NULL; a = a->outchain)
- for (aa = a->to->outs; aa != NULL; aa = aa->outchain)
- if (aa->to == nfa->post)
- return REG_UEMPTYMATCH;
- return 0;
+static long /* re_info bits to be ORed in */
+analyze(struct nfa *nfa) {
+ struct arc *a;
+ struct arc *aa;
+
+ if (nfa->pre->outs == NULL) return REG_UIMPOSSIBLE;
+ for (a = nfa->pre->outs; a != NULL; a = a->outchain)
+ for (aa = a->to->outs; aa != NULL; aa = aa->outchain)
+ if (aa->to == nfa->post) return REG_UEMPTYMATCH;
+ return 0;
}
/*
* compact - compact an NFA
*/
-static void
-compact(struct nfa * nfa,
- struct cnfa * cnfa)
-{
- struct state *s;
- struct arc *a;
- size_t nstates;
- size_t narcs;
- struct carc *ca;
- struct carc *first;
-
- assert(!NISERR());
-
- nstates = 0;
- narcs = 0;
- for (s = nfa->states; s != NULL; s = s->next)
- {
- nstates++;
- narcs += 1 + s->nouts + 1;
- /* 1 as a fake for flags, nouts for arcs, 1 as endmarker */
- }
-
- cnfa->states = (struct carc **) MALLOC(nstates * sizeof(struct carc *));
- cnfa->arcs = (struct carc *) MALLOC(narcs * sizeof(struct carc));
- if (cnfa->states == NULL || cnfa->arcs == NULL)
- {
- if (cnfa->states != NULL)
- FREE(cnfa->states);
- if (cnfa->arcs != NULL)
- FREE(cnfa->arcs);
- NERR(REG_ESPACE);
- return;
- }
- cnfa->nstates = nstates;
- cnfa->pre = nfa->pre->no;
- cnfa->post = nfa->post->no;
- cnfa->bos[0] = nfa->bos[0];
- cnfa->bos[1] = nfa->bos[1];
- cnfa->eos[0] = nfa->eos[0];
- cnfa->eos[1] = nfa->eos[1];
- cnfa->ncolors = maxcolor(nfa->cm) + 1;
- cnfa->flags = 0;
-
- ca = cnfa->arcs;
- for (s = nfa->states; s != NULL; s = s->next)
- {
- assert((size_t) s->no < nstates);
- cnfa->states[s->no] = ca;
- ca->co = 0; /* clear and skip flags "arc" */
- ca++;
- first = ca;
- for (a = s->outs; a != NULL; a = a->outchain)
- switch (a->type)
- {
- case PLAIN:
- ca->co = a->co;
- ca->to = a->to->no;
- ca++;
- break;
- case LACON:
- assert(s->no != cnfa->pre);
- ca->co = (color) (cnfa->ncolors + a->co);
- ca->to = a->to->no;
- ca++;
- cnfa->flags |= HASLACONS;
- break;
- default:
- assert(NOTREACHED);
- break;
- }
- carcsort(first, ca - 1);
- ca->co = COLORLESS;
- ca->to = 0;
- ca++;
- }
- assert(ca == &cnfa->arcs[narcs]);
- assert(cnfa->nstates != 0);
-
- /* mark no-progress states */
- for (a = nfa->pre->outs; a != NULL; a = a->outchain)
- cnfa->states[a->to->no]->co = 1;
- cnfa->states[nfa->pre->no]->co = 1;
+static void compact(struct nfa *nfa, struct cnfa *cnfa) {
+ struct state *s;
+ struct arc *a;
+ size_t nstates;
+ size_t narcs;
+ struct carc *ca;
+ struct carc *first;
+
+ assert(!NISERR());
+
+ nstates = 0;
+ narcs = 0;
+ for (s = nfa->states; s != NULL; s = s->next) {
+ nstates++;
+ narcs += 1 + s->nouts + 1;
+ /* 1 as a fake for flags, nouts for arcs, 1 as endmarker */
+ }
+
+ cnfa->states = (struct carc **)MALLOC(nstates * sizeof(struct carc *));
+ cnfa->arcs = (struct carc *)MALLOC(narcs * sizeof(struct carc));
+ if (cnfa->states == NULL || cnfa->arcs == NULL) {
+ if (cnfa->states != NULL) FREE(cnfa->states);
+ if (cnfa->arcs != NULL) FREE(cnfa->arcs);
+ NERR(REG_ESPACE);
+ return;
+ }
+ cnfa->nstates = nstates;
+ cnfa->pre = nfa->pre->no;
+ cnfa->post = nfa->post->no;
+ cnfa->bos[0] = nfa->bos[0];
+ cnfa->bos[1] = nfa->bos[1];
+ cnfa->eos[0] = nfa->eos[0];
+ cnfa->eos[1] = nfa->eos[1];
+ cnfa->ncolors = maxcolor(nfa->cm) + 1;
+ cnfa->flags = 0;
+
+ ca = cnfa->arcs;
+ for (s = nfa->states; s != NULL; s = s->next) {
+ assert((size_t)s->no < nstates);
+ cnfa->states[s->no] = ca;
+ ca->co = 0; /* clear and skip flags "arc" */
+ ca++;
+ first = ca;
+ for (a = s->outs; a != NULL; a = a->outchain) switch (a->type) {
+ case PLAIN:
+ ca->co = a->co;
+ ca->to = a->to->no;
+ ca++;
+ break;
+ case LACON:
+ assert(s->no != cnfa->pre);
+ ca->co = (color)(cnfa->ncolors + a->co);
+ ca->to = a->to->no;
+ ca++;
+ cnfa->flags |= HASLACONS;
+ break;
+ default:
+ assert(NOTREACHED);
+ break;
+ }
+ carcsort(first, ca - 1);
+ ca->co = COLORLESS;
+ ca->to = 0;
+ ca++;
+ }
+ assert(ca == &cnfa->arcs[narcs]);
+ assert(cnfa->nstates != 0);
+
+ /* mark no-progress states */
+ for (a = nfa->pre->outs; a != NULL; a = a->outchain)
+ cnfa->states[a->to->no]->co = 1;
+ cnfa->states[nfa->pre->no]->co = 1;
}
/*
@@ -1402,260 +1334,199 @@ compact(struct nfa * nfa,
* Really dumb algorithm, but if the list is long enough for that to matter,
* you're in real trouble anyway.
*/
-static void
-carcsort(struct carc * first,
- struct carc * last)
-{
- struct carc *p;
- struct carc *q;
- struct carc tmp;
-
- if (last - first <= 1)
- return;
-
- for (p = first; p <= last; p++)
- for (q = p; q <= last; q++)
- if (p->co > q->co ||
- (p->co == q->co && p->to > q->to))
- {
- assert(p != q);
- tmp = *p;
- *p = *q;
- *q = tmp;
- }
+static void carcsort(struct carc *first, struct carc *last) {
+ struct carc *p;
+ struct carc *q;
+ struct carc tmp;
+
+ if (last - first <= 1) return;
+
+ for (p = first; p <= last; p++)
+ for (q = p; q <= last; q++)
+ if (p->co > q->co || (p->co == q->co && p->to > q->to)) {
+ assert(p != q);
+ tmp = *p;
+ *p = *q;
+ *q = tmp;
+ }
}
/*
* freecnfa - free a compacted NFA
*/
-static void
-freecnfa(struct cnfa * cnfa)
-{
- assert(cnfa->nstates != 0); /* not empty already */
- cnfa->nstates = 0;
- FREE(cnfa->states);
- FREE(cnfa->arcs);
+static void freecnfa(struct cnfa *cnfa) {
+ assert(cnfa->nstates != 0); /* not empty already */
+ cnfa->nstates = 0;
+ FREE(cnfa->states);
+ FREE(cnfa->arcs);
}
/*
* dumpnfa - dump an NFA in human-readable form
*/
-static void
-dumpnfa(struct nfa * nfa,
- FILE *f)
-{
+static void dumpnfa(struct nfa *nfa, FILE *f) {
#ifdef REG_DEBUG
- struct state *s;
-
- fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no);
- if (nfa->bos[0] != COLORLESS)
- fprintf(f, ", bos [%ld]", (long) nfa->bos[0]);
- if (nfa->bos[1] != COLORLESS)
- fprintf(f, ", bol [%ld]", (long) nfa->bos[1]);
- if (nfa->eos[0] != COLORLESS)
- fprintf(f, ", eos [%ld]", (long) nfa->eos[0]);
- if (nfa->eos[1] != COLORLESS)
- fprintf(f, ", eol [%ld]", (long) nfa->eos[1]);
- fprintf(f, "\n");
- for (s = nfa->states; s != NULL; s = s->next)
- dumpstate(s, f);
- if (nfa->parent == NULL)
- dumpcolors(nfa->cm, f);
- fflush(f);
+ struct state *s;
+
+ fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no);
+ if (nfa->bos[0] != COLORLESS) fprintf(f, ", bos [%ld]", (long)nfa->bos[0]);
+ if (nfa->bos[1] != COLORLESS) fprintf(f, ", bol [%ld]", (long)nfa->bos[1]);
+ if (nfa->eos[0] != COLORLESS) fprintf(f, ", eos [%ld]", (long)nfa->eos[0]);
+ if (nfa->eos[1] != COLORLESS) fprintf(f, ", eol [%ld]", (long)nfa->eos[1]);
+ fprintf(f, "\n");
+ for (s = nfa->states; s != NULL; s = s->next) dumpstate(s, f);
+ if (nfa->parent == NULL) dumpcolors(nfa->cm, f);
+ fflush(f);
#endif
}
-#ifdef REG_DEBUG /* subordinates of dumpnfa */
+#ifdef REG_DEBUG /* subordinates of dumpnfa */
/*
* dumpstate - dump an NFA state in human-readable form
*/
-static void
-dumpstate(struct state * s,
- FILE *f)
-{
- struct arc *a;
-
- fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "",
- (s->flag) ? s->flag : '.');
- if (s->prev != NULL && s->prev->next != s)
- fprintf(f, "\tstate chain bad\n");
- if (s->nouts == 0)
- fprintf(f, "\tno out arcs\n");
- else
- dumparcs(s, f);
- fflush(f);
- for (a = s->ins; a != NULL; a = a->inchain)
- {
- if (a->to != s)
- fprintf(f, "\tlink from %d to %d on %d's in-chain\n",
- a->from->no, a->to->no, s->no);
- }
+static void dumpstate(struct state *s, FILE *f) {
+ struct arc *a;
+
+ fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "",
+ (s->flag) ? s->flag : '.');
+ if (s->prev != NULL && s->prev->next != s) fprintf(f, "\tstate chain bad\n");
+ if (s->nouts == 0)
+ fprintf(f, "\tno out arcs\n");
+ else
+ dumparcs(s, f);
+ fflush(f);
+ for (a = s->ins; a != NULL; a = a->inchain) {
+ if (a->to != s)
+ fprintf(f, "\tlink from %d to %d on %d's in-chain\n", a->from->no,
+ a->to->no, s->no);
+ }
}
/*
* dumparcs - dump out-arcs in human-readable form
*/
-static void
-dumparcs(struct state * s,
- FILE *f)
-{
- int pos;
+static void dumparcs(struct state *s, FILE *f) {
+ int pos;
- assert(s->nouts > 0);
- /* printing arcs in reverse order is usually clearer */
- pos = dumprarcs(s->outs, s, f, 1);
- if (pos != 1)
- fprintf(f, "\n");
+ assert(s->nouts > 0);
+ /* printing arcs in reverse order is usually clearer */
+ pos = dumprarcs(s->outs, s, f, 1);
+ if (pos != 1) fprintf(f, "\n");
}
/*
* dumprarcs - dump remaining outarcs, recursively, in reverse order
*/
-static int /* resulting print position */
-dumprarcs(struct arc * a,
- struct state * s,
- FILE *f,
- int pos) /* initial print position */
+static int /* resulting print position */
+dumprarcs(struct arc *a, struct state *s, FILE *f,
+ int pos) /* initial print position */
{
- if (a->outchain != NULL)
- pos = dumprarcs(a->outchain, s, f, pos);
- dumparc(a, s, f);
- if (pos == 5)
- {
- fprintf(f, "\n");
- pos = 1;
- }
- else
- pos++;
- return pos;
+ if (a->outchain != NULL) pos = dumprarcs(a->outchain, s, f, pos);
+ dumparc(a, s, f);
+ if (pos == 5) {
+ fprintf(f, "\n");
+ pos = 1;
+ } else
+ pos++;
+ return pos;
}
/*
* dumparc - dump one outarc in readable form, including prefixing tab
*/
-static void
-dumparc(struct arc * a,
- struct state * s,
- FILE *f)
-{
- struct arc *aa;
- struct arcbatch *ab;
-
- fprintf(f, "\t");
- switch (a->type)
- {
- case PLAIN:
- fprintf(f, "[%ld]", (long) a->co);
- break;
- case AHEAD:
- fprintf(f, ">%ld>", (long) a->co);
- break;
- case BEHIND:
- fprintf(f, "<%ld<", (long) a->co);
- break;
- case LACON:
- fprintf(f, ":%ld:", (long) a->co);
- break;
- case '^':
- case '$':
- fprintf(f, "%c%d", a->type, (int) a->co);
- break;
- case EMPTY:
- break;
- default:
- fprintf(f, "0x%x/0%lo", a->type, (long) a->co);
- break;
- }
- if (a->from != s)
- fprintf(f, "?%d?", a->from->no);
- for (ab = &a->from->oas; ab != NULL; ab = ab->next)
- {
- for (aa = &ab->a[0]; aa < &ab->a[ABSIZE]; aa++)
- if (aa == a)
- break; /* NOTE BREAK OUT */
- if (aa < &ab->a[ABSIZE]) /* propagate break */
- break; /* NOTE BREAK OUT */
- }
- if (ab == NULL)
- fprintf(f, "?!?"); /* not in allocated space */
- fprintf(f, "->");
- if (a->to == NULL)
- {
- fprintf(f, "NULL");
- return;
- }
- fprintf(f, "%d", a->to->no);
- for (aa = a->to->ins; aa != NULL; aa = aa->inchain)
- if (aa == a)
- break; /* NOTE BREAK OUT */
- if (aa == NULL)
- fprintf(f, "?!?"); /* missing from in-chain */
+static void dumparc(struct arc *a, struct state *s, FILE *f) {
+ struct arc *aa;
+ struct arcbatch *ab;
+
+ fprintf(f, "\t");
+ switch (a->type) {
+ case PLAIN:
+ fprintf(f, "[%ld]", (long)a->co);
+ break;
+ case AHEAD:
+ fprintf(f, ">%ld>", (long)a->co);
+ break;
+ case BEHIND:
+ fprintf(f, "<%ld<", (long)a->co);
+ break;
+ case LACON:
+ fprintf(f, ":%ld:", (long)a->co);
+ break;
+ case '^':
+ case '$':
+ fprintf(f, "%c%d", a->type, (int)a->co);
+ break;
+ case EMPTY:
+ break;
+ default:
+ fprintf(f, "0x%x/0%lo", a->type, (long)a->co);
+ break;
+ }
+ if (a->from != s) fprintf(f, "?%d?", a->from->no);
+ for (ab = &a->from->oas; ab != NULL; ab = ab->next) {
+ for (aa = &ab->a[0]; aa < &ab->a[ABSIZE]; aa++)
+ if (aa == a) break; /* NOTE BREAK OUT */
+ if (aa < &ab->a[ABSIZE]) /* propagate break */
+ break; /* NOTE BREAK OUT */
+ }
+ if (ab == NULL) fprintf(f, "?!?"); /* not in allocated space */
+ fprintf(f, "->");
+ if (a->to == NULL) {
+ fprintf(f, "NULL");
+ return;
+ }
+ fprintf(f, "%d", a->to->no);
+ for (aa = a->to->ins; aa != NULL; aa = aa->inchain)
+ if (aa == a) break; /* NOTE BREAK OUT */
+ if (aa == NULL) fprintf(f, "?!?"); /* missing from in-chain */
}
-#endif /* REG_DEBUG */
+#endif /* REG_DEBUG */
/*
* dumpcnfa - dump a compacted NFA in human-readable form
*/
#ifdef REG_DEBUG
-static void
-dumpcnfa(struct cnfa * cnfa,
- FILE *f)
-{
- int st;
-
- fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post);
- if (cnfa->bos[0] != COLORLESS)
- fprintf(f, ", bos [%ld]", (long) cnfa->bos[0]);
- if (cnfa->bos[1] != COLORLESS)
- fprintf(f, ", bol [%ld]", (long) cnfa->bos[1]);
- if (cnfa->eos[0] != COLORLESS)
- fprintf(f, ", eos [%ld]", (long) cnfa->eos[0]);
- if (cnfa->eos[1] != COLORLESS)
- fprintf(f, ", eol [%ld]", (long) cnfa->eos[1]);
- if (cnfa->flags & HASLACONS)
- fprintf(f, ", haslacons");
- fprintf(f, "\n");
- for (st = 0; st < cnfa->nstates; st++)
- dumpcstate(st, cnfa->states[st], cnfa, f);
- fflush(f);
+static void dumpcnfa(struct cnfa *cnfa, FILE *f) {
+ int st;
+
+ fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post);
+ if (cnfa->bos[0] != COLORLESS) fprintf(f, ", bos [%ld]", (long)cnfa->bos[0]);
+ if (cnfa->bos[1] != COLORLESS) fprintf(f, ", bol [%ld]", (long)cnfa->bos[1]);
+ if (cnfa->eos[0] != COLORLESS) fprintf(f, ", eos [%ld]", (long)cnfa->eos[0]);
+ if (cnfa->eos[1] != COLORLESS) fprintf(f, ", eol [%ld]", (long)cnfa->eos[1]);
+ if (cnfa->flags & HASLACONS) fprintf(f, ", haslacons");
+ fprintf(f, "\n");
+ for (st = 0; st < cnfa->nstates; st++)
+ dumpcstate(st, cnfa->states[st], cnfa, f);
+ fflush(f);
}
#endif
-#ifdef REG_DEBUG /* subordinates of dumpcnfa */
+#ifdef REG_DEBUG /* subordinates of dumpcnfa */
/*
* dumpcstate - dump a compacted-NFA state in human-readable form
*/
-static void
-dumpcstate(int st,
- struct carc * ca,
- struct cnfa * cnfa,
- FILE *f)
-{
- int i;
- int pos;
-
- fprintf(f, "%d%s", st, (ca[0].co) ? ":" : ".");
- pos = 1;
- for (i = 1; ca[i].co != COLORLESS; i++)
- {
- if (ca[i].co < cnfa->ncolors)
- fprintf(f, "\t[%ld]->%d", (long) ca[i].co, ca[i].to);
- else
- fprintf(f, "\t:%ld:->%d", (long) ca[i].co - cnfa->ncolors,
- ca[i].to);
- if (pos == 5)
- {
- fprintf(f, "\n");
- pos = 1;
- }
- else
- pos++;
- }
- if (i == 1 || pos != 1)
- fprintf(f, "\n");
- fflush(f);
+static void dumpcstate(int st, struct carc *ca, struct cnfa *cnfa, FILE *f) {
+ int i;
+ int pos;
+
+ fprintf(f, "%d%s", st, (ca[0].co) ? ":" : ".");
+ pos = 1;
+ for (i = 1; ca[i].co != COLORLESS; i++) {
+ if (ca[i].co < cnfa->ncolors)
+ fprintf(f, "\t[%ld]->%d", (long)ca[i].co, ca[i].to);
+ else
+ fprintf(f, "\t:%ld:->%d", (long)ca[i].co - cnfa->ncolors, ca[i].to);
+ if (pos == 5) {
+ fprintf(f, "\n");
+ pos = 1;
+ } else
+ pos++;
+ }
+ if (i == 1 || pos != 1) fprintf(f, "\n");
+ fflush(f);
}
-#endif /* REG_DEBUG */
+#endif /* REG_DEBUG */
diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
index 35c4d99..aefd1ba 100644
--- a/src/backend/regex/regcomp.c
+++ b/src/backend/regex/regcomp.c
@@ -122,12 +122,15 @@ static void destroystate(struct nfa *, struct state *);
static void newarc(struct nfa *, int, pcolor, struct state *, struct state *);
static struct arc *allocarc(struct nfa *, struct state *);
static void freearc(struct nfa *, struct arc *);
+static int hasnonemptyout(struct state *);
+static int nonemptyouts(struct state *);
+static int nonemptyins(struct state *);
static struct arc *findarc(struct state *, int, pcolor);
static void cparc(struct nfa *, struct arc *, struct state *, struct state *);
static void moveins(struct nfa *, struct state *, struct state *);
-static void copyins(struct nfa *, struct state *, struct state *);
+static void copyins(struct nfa *, struct state *, struct state *, int);
static void moveouts(struct nfa *, struct state *, struct state *);
-static void copyouts(struct nfa *, struct state *, struct state *);
+static void copyouts(struct nfa *, struct state *, struct state *, int);
static void cloneouts(struct nfa *, struct state *, struct state *, struct state *, int);
static void delsub(struct nfa *, struct state *, struct state *);
static void deltraverse(struct nfa *, struct state *, struct state *);
@@ -146,7 +149,8 @@ static int push(struct nfa *, struct arc *);
#define COMPATIBLE 3 /* compatible but not satisfied yet */
static int combine(struct arc *, struct arc *);
static void fixempties(struct nfa *, FILE *);
-static int unempty(struct nfa *, struct arc *);
+static struct state *emptyreachable(struct state *, struct state *);
+static void replaceempty(struct nfa *, struct state *, struct state *);
static void cleanup(struct nfa *);
static void markreachable(struct nfa *, struct state *, struct state *, struct state *);
static void markcanreach(struct nfa *, struct state *, struct state *, struct state *);
@@ -573,7 +577,7 @@ makesearch(struct vars * v,
for (s = slist; s != NULL; s = s2)
{
s2 = newstate(nfa);
- copyouts(nfa, s, s2);
+ copyouts(nfa, s, s2, 1);
for (a = s->ins; a != NULL; a = b)
{
b = a->inchain;