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-rw-r--r--generic/regc_nfa.c1914
1 files changed, 1540 insertions, 374 deletions
diff --git a/generic/regc_nfa.c b/generic/regc_nfa.c
index 1d572c3..6280e5e 100644
--- a/generic/regc_nfa.c
+++ b/generic/regc_nfa.c
@@ -34,6 +34,9 @@
#define NISERR() VISERR(nfa->v)
#define NERR(e) VERR(nfa->v, (e))
+#define STACK_TOO_DEEP(x) (0)
+#define CANCEL_REQUESTED(x) (0)
+#define REG_CANCEL 777
/*
- newnfa - set up an NFA
@@ -59,7 +62,6 @@ newnfa(
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. */
@@ -87,61 +89,6 @@ newnfa(
}
/*
- - TooManyStates - checks if the max states exceeds the compile-time value
- ^ static int TooManyStates(struct nfa *);
- */
-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 *);
- */
-static void
-IncrementSize(
- struct nfa *nfa)
-{
- struct nfa *parent = nfa->parent;
-
- nfa->size++;
- while (parent != NULL) {
- parent->size++;
- parent = parent->parent;
- }
-}
-
-/*
- - DecrementSize - increases the tracked size of the NFA and its parents.
- ^ static void DecrementSize(struct nfa *);
- */
-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 *);
*/
@@ -177,20 +124,20 @@ newstate(
{
struct state *s;
- if (TooManyStates(nfa)) {
- /* XXX: add specific error for this */
- NERR(REG_ETOOBIG);
- return NULL;
- }
if (nfa->free != NULL) {
s = nfa->free;
nfa->free = s->next;
} else {
+ if (nfa->v->spaceused >= REG_MAX_COMPILE_SPACE) {
+ NERR(REG_ETOOBIG);
+ return NULL;
+ }
s = (struct state *) MALLOC(sizeof(struct state));
if (s == NULL) {
NERR(REG_ESPACE);
return NULL;
}
+ nfa->v->spaceused += sizeof(struct state);
s->oas.next = NULL;
s->free = NULL;
s->noas = 0;
@@ -214,12 +161,6 @@ newstate(
}
s->prev = nfa->slast;
nfa->slast = s;
-
- /*
- * Track the current size and the parent size.
- */
-
- IncrementSize(nfa);
return s;
}
@@ -290,7 +231,6 @@ freestate(
s->prev = NULL;
s->next = nfa->free; /* don't delete it, put it on the free list */
nfa->free = s;
- DecrementSize(nfa);
}
/*
@@ -309,11 +249,13 @@ destroystate(
for (ab=s->oas.next ; ab!=NULL ; ab=abnext) {
abnext = ab->next;
FREE(ab);
+ nfa->v->spaceused -= sizeof(struct arcbatch);
}
s->ins = NULL;
s->outs = NULL;
s->next = NULL;
FREE(s);
+ nfa->v->spaceused -= sizeof(struct state);
}
/*
@@ -321,6 +263,10 @@ destroystate(
^ static VOID newarc(struct nfa *, int, pcolor, struct state *,
^ struct state *);
*/
+/*
+ * This function checks to make sure that no duplicate arcs are created.
+ * In general we never want duplicates.
+ */
static void
newarc(
struct nfa *nfa,
@@ -333,16 +279,42 @@ newarc(
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;
+ /* check for duplicate arc, using whichever chain is shorter */
+ if (from->nouts <= to->nins) {
+ for (a = from->outs; a != NULL; a = a->outchain) {
+ if (a->to == to && a->co == co && a->type == t) {
+ return;
+ }
+ }
+ } else {
+ for (a = to->ins; a != NULL; a = a->inchain) {
+ if (a->from == from && a->co == co && a->type == t) {
+ return;
+ }
}
}
+
+ /* no dup, so create the arc */
+ createarc(nfa, t, co, from, to);
+}
+/*
+ * createarc - create a new arc within an NFA
+ *
+ * This function must *only* be used after verifying that there is no existing
+ * identical arc (same type/color/from/to).
+ */
+static void
+createarc(
+ struct nfa * nfa,
+ int t,
+ pcolor co,
+ struct state * from,
+ struct state * to)
+{
+ struct arc *a;
+
+ /* the arc is physically allocated within its from-state */
a = allocarc(nfa, from);
if (NISERR()) {
return;
@@ -355,15 +327,21 @@ newarc(
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.
+ * Put the new arc on the beginning, not the end, of the chains; it's
+ * simpler here, and freearc() is the same cost either way. See also the
+ * logic in moveins() and its cohorts, as well as fixempties().
*/
-
a->inchain = to->ins;
+ a->inchainRev = NULL;
+ if (to->ins) {
+ to->ins->inchainRev = a;
+ }
to->ins = a;
a->outchain = from->outs;
+ a->outchainRev = NULL;
+ if (from->outs) {
+ from->outs->outchainRev = a;
+ }
from->outs = a;
from->nouts++;
@@ -400,14 +378,19 @@ allocarc(
*/
if (s->free == NULL) {
- struct arcbatch *newAb = (struct arcbatch *)
- MALLOC(sizeof(struct arcbatch));
+ struct arcbatch *newAb;
int i;
+ if (nfa->v->spaceused >= REG_MAX_COMPILE_SPACE) {
+ NERR(REG_ETOOBIG);
+ return NULL;
+ }
+ newAb = (struct arcbatch *) MALLOC(sizeof(struct arcbatch));
if (newAb == NULL) {
NERR(REG_ESPACE);
return NULL;
}
+ nfa->v->spaceused += sizeof(struct arcbatch);
newAb->next = s->oas.next;
s->oas.next = newAb;
@@ -436,7 +419,7 @@ freearc(
{
struct state *from = victim->from;
struct state *to = victim->to;
- struct arc *a;
+ struct arc *predecessor;
assert(victim->type != 0);
@@ -453,16 +436,17 @@ freearc(
*/
assert(from != NULL);
- assert(from->outs != NULL);
- a = from->outs;
- if (a == victim) { /* simple case: first in chain */
+ predecessor = victim->outchainRev;
+ if (predecessor == NULL) {
+ assert(from->outs == victim);
from->outs = victim->outchain;
} else {
- for (; a!=NULL && a->outchain!=victim ; a=a->outchain) {
- continue;
- }
- assert(a != NULL);
- a->outchain = victim->outchain;
+ assert(predecessor->outchain == victim);
+ predecessor->outchain = victim->outchain;
+ }
+ if (victim->outchain != NULL) {
+ assert(victim->outchain->outchainRev == victim);
+ victim->outchain->outchainRev = predecessor;
}
from->nouts--;
@@ -471,86 +455,95 @@ freearc(
*/
assert(to != NULL);
- assert(to->ins != NULL);
- a = to->ins;
- if (a == victim) { /* simple case: first in chain */
+ predecessor = victim->inchainRev;
+ if (predecessor == NULL) {
+ assert(to->ins == victim);
to->ins = victim->inchain;
} else {
- for (; a->inchain!=victim ; a=a->inchain) {
- assert(a->inchain != NULL);
- continue;
- }
- a->inchain = victim->inchain;
+ assert(predecessor->inchain == victim);
+ predecessor->inchain = victim->inchain;
+ }
+ if (victim->inchain != NULL) {
+ assert(victim->inchain->inchainRev == victim);
+ victim->inchain->inchainRev = predecessor;
}
to->nins--;
/*
- * Clean up and place on free list.
+ * Clean up and place on from-state's free list.
*/
victim->type = 0;
victim->from = NULL; /* precautions... */
victim->to = NULL;
victim->inchain = NULL;
+ victim->inchainRev = NULL;
victim->outchain = NULL;
+ victim->outchainRev = NULL;
victim->freechain = from->free;
from->free = victim;
}
-
+
/*
- - hasnonemptyout - Does state have a non-EMPTY out arc?
- ^ static int hasnonemptyout(struct state *);
+ * changearctarget - flip an arc to have a different to state
+ *
+ * Caller must have verified that there is no pre-existing duplicate arc.
+ *
+ * Note that because we store arcs in their from state, we can't easily have
+ * a similar changearcsource function.
*/
-static int
-hasnonemptyout(
- struct state *s)
+static void
+changearctarget(struct arc * a, struct state * newto)
{
- struct arc *a;
+ struct state *oldto = a->to;
+ struct arc *predecessor;
- for (a = s->outs; a != NULL; a = a->outchain) {
- if (a->type != EMPTY) {
- return 1;
- }
+ assert(oldto != newto);
+
+ /* take it off old target's in-chain */
+ assert(oldto != NULL);
+ predecessor = a->inchainRev;
+ if (predecessor == NULL) {
+ assert(oldto->ins == a);
+ oldto->ins = a->inchain;
+ } else {
+ assert(predecessor->inchain == a);
+ predecessor->inchain = a->inchain;
}
- return 0;
-}
-
-/*
- - nonemptyouts - count non-EMPTY out arcs of a state
- ^ static int nonemptyouts(struct state *);
- */
-static int
-nonemptyouts(
- struct state *s)
-{
- int n = 0;
- struct arc *a;
+ if (a->inchain != NULL) {
+ assert(a->inchain->inchainRev == a);
+ a->inchain->inchainRev = predecessor;
+ }
+ oldto->nins--;
- for (a = s->outs; a != NULL; a = a->outchain) {
- if (a->type != EMPTY) {
- n++;
- }
+ a->to = newto;
+
+ /* prepend it to new target's in-chain */
+ a->inchain = newto->ins;
+ a->inchainRev = NULL;
+ if (newto->ins) {
+ newto->ins->inchainRev = a;
}
- return n;
+ newto->ins = a;
+ newto->nins++;
}
/*
- - nonemptyins - count non-EMPTY in arcs of a state
- ^ static int nonemptyins(struct state *);
+ - hasnonemptyout - Does state have a non-EMPTY out arc?
+ ^ static int hasnonemptyout(struct state *);
*/
static int
-nonemptyins(
+hasnonemptyout(
struct state *s)
{
- int n = 0;
struct arc *a;
- for (a = s->ins; a != NULL; a = a->inchain) {
+ for (a = s->outs; a != NULL; a = a->outchain) {
if (a->type != EMPTY) {
- n++;
+ return 1;
}
}
- return n;
+ return 0;
}
/*
@@ -588,13 +581,181 @@ cparc(
{
newarc(nfa, oa->type, oa->co, from, to);
}
+
+/*
+ * sortins - sort the in arcs of a state by from/color/type
+ */
+static void
+sortins(
+ struct nfa * nfa,
+ struct state * s)
+{
+ struct arc **sortarray;
+ struct arc *a;
+ int n = s->nins;
+ int i;
+
+ if (n <= 1) {
+ return; /* nothing to do */
+ }
+ /* make an array of arc pointers ... */
+ sortarray = (struct arc **) MALLOC(n * sizeof(struct arc *));
+ if (sortarray == NULL) {
+ NERR(REG_ESPACE);
+ return;
+ }
+ i = 0;
+ for (a = s->ins; a != NULL; a = a->inchain) {
+ sortarray[i++] = a;
+ }
+ assert(i == n);
+ /* ... sort the array */
+ qsort(sortarray, n, sizeof(struct arc *), sortins_cmp);
+ /* ... and rebuild arc list in order */
+ /* it seems worth special-casing first and last items to simplify loop */
+ a = sortarray[0];
+ s->ins = a;
+ a->inchain = sortarray[1];
+ a->inchainRev = NULL;
+ for (i = 1; i < n - 1; i++) {
+ a = sortarray[i];
+ a->inchain = sortarray[i + 1];
+ a->inchainRev = sortarray[i - 1];
+ }
+ a = sortarray[i];
+ a->inchain = NULL;
+ a->inchainRev = sortarray[i - 1];
+ FREE(sortarray);
+}
+
+static int
+sortins_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct arc *aa = *((const struct arc * const *) a);
+ const struct arc *bb = *((const struct arc * const *) b);
+
+ /* we check the fields in the order they are most likely to be different */
+ if (aa->from->no < bb->from->no) {
+ return -1;
+ }
+ if (aa->from->no > bb->from->no) {
+ return 1;
+ }
+ if (aa->co < bb->co) {
+ return -1;
+ }
+ if (aa->co > bb->co) {
+ return 1;
+ }
+ if (aa->type < bb->type) {
+ return -1;
+ }
+ if (aa->type > bb->type) {
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * sortouts - sort the out arcs of a state by to/color/type
+ */
+static void
+sortouts(
+ struct nfa * nfa,
+ struct state * s)
+{
+ struct arc **sortarray;
+ struct arc *a;
+ int n = s->nouts;
+ int i;
+
+ if (n <= 1) {
+ return; /* nothing to do */
+ }
+ /* make an array of arc pointers ... */
+ sortarray = (struct arc **) MALLOC(n * sizeof(struct arc *));
+ if (sortarray == NULL) {
+ NERR(REG_ESPACE);
+ return;
+ }
+ i = 0;
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ sortarray[i++] = a;
+ }
+ assert(i == n);
+ /* ... sort the array */
+ qsort(sortarray, n, sizeof(struct arc *), sortouts_cmp);
+ /* ... and rebuild arc list in order */
+ /* it seems worth special-casing first and last items to simplify loop */
+ a = sortarray[0];
+ s->outs = a;
+ a->outchain = sortarray[1];
+ a->outchainRev = NULL;
+ for (i = 1; i < n - 1; i++) {
+ a = sortarray[i];
+ a->outchain = sortarray[i + 1];
+ a->outchainRev = sortarray[i - 1];
+ }
+ a = sortarray[i];
+ a->outchain = NULL;
+ a->outchainRev = sortarray[i - 1];
+ FREE(sortarray);
+}
+
+static int
+sortouts_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct arc *aa = *((const struct arc * const *) a);
+ const struct arc *bb = *((const struct arc * const *) b);
+
+ /* we check the fields in the order they are most likely to be different */
+ if (aa->to->no < bb->to->no) {
+ return -1;
+ }
+ if (aa->to->no > bb->to->no) {
+ return 1;
+ }
+ if (aa->co < bb->co) {
+ return -1;
+ }
+ if (aa->co > bb->co) {
+ return 1;
+ }
+ if (aa->type < bb->type) {
+ return -1;
+ }
+ if (aa->type > bb->type) {
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Common decision logic about whether to use arc-by-arc operations or
+ * sort/merge. If there's just a few source arcs we cannot recoup the
+ * cost of sorting the destination arc list, no matter how large it is.
+ * Otherwise, limit the number of arc-by-arc comparisons to about 1000
+ * (a somewhat arbitrary choice, but the breakeven point would probably
+ * be machine dependent anyway).
+ */
+#define BULK_ARC_OP_USE_SORT(nsrcarcs, ndestarcs) \
+ ((nsrcarcs) < 4 ? 0 : ((nsrcarcs) > 32 || (ndestarcs) > 32))
/*
- moveins - move all in arcs of a state to another state
* You might think this could be done better by just updating the
- * existing arcs, and you would be right if it weren't for the desire
+ * existing arcs, and you would be right if it weren't for the need
* for duplicate suppression, which makes it easier to just make new
* ones to exploit the suppression built into newarc.
+ *
+ * However, if we have a whole lot of arcs to deal with, retail duplicate
+ * checks become too slow. In that case we proceed by sorting and merging
+ * the arc lists, and then we can indeed just update the arcs in-place.
+ *
^ static VOID moveins(struct nfa *, struct state *, struct state *);
*/
static void
@@ -603,38 +764,253 @@ moveins(
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);
+ if (!BULK_ARC_OP_USE_SORT(oldState->nins, newState->nins)) {
+ /* With not too many arcs, just do them one at a time */
+ struct arc *a;
+
+ while ((a = oldState->ins) != NULL) {
+ cparc(nfa, a, a->from, newState);
+ freearc(nfa, a);
+ }
+ } else {
+ /*
+ * With many arcs, use a sort-merge approach. Note changearctarget()
+ * will put the arc onto the front of newState's chain, so it does not
+ * break our walk through the sorted part of the chain.
+ */
+ struct arc *oa;
+ struct arc *na;
+
+ /*
+ * Because we bypass newarc() in this code path, we'd better include a
+ * cancel check.
+ */
+ if (CANCEL_REQUESTED(nfa->v->re)) {
+ NERR(REG_CANCEL);
+ return;
+ }
+
+ sortins(nfa, oldState);
+ sortins(nfa, newState);
+ if (NISERR()) {
+ return; /* might have failed to sort */
+ }
+ oa = oldState->ins;
+ na = newState->ins;
+ while (oa != NULL && na != NULL) {
+ struct arc *a = oa;
+
+ switch (sortins_cmp(&oa, &na)) {
+ case -1:
+ /* newState does not have anything matching oa */
+ oa = oa->inchain;
+
+ /*
+ * Rather than doing createarc+freearc, we can just unlink
+ * and relink the existing arc struct.
+ */
+ changearctarget(a, newState);
+ break;
+ case 0:
+ /* match, advance in both lists */
+ oa = oa->inchain;
+ na = na->inchain;
+ /* ... and drop duplicate arc from oldState */
+ freearc(nfa, a);
+ break;
+ case +1:
+ /* advance only na; oa might have a match later */
+ na = na->inchain;
+ break;
+ default:
+ assert(NOTREACHED);
+ }
+ }
+ while (oa != NULL) {
+ /* newState does not have anything matching oa */
+ struct arc *a = oa;
+
+ oa = oa->inchain;
+ changearctarget(a, newState);
+ }
}
+
assert(oldState->nins == 0);
assert(oldState->ins == NULL);
}
/*
- 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 *, struct state *, struct state *, int);
*/
static void
copyins(
struct nfa *nfa,
struct state *oldState,
- struct state *newState,
- int all)
+ struct state *newState)
{
- struct arc *a;
-
assert(oldState != newState);
- for (a=oldState->ins ; a!=NULL ; a=a->inchain) {
- if (all || a->type != EMPTY) {
+ if (!BULK_ARC_OP_USE_SORT(oldState->nins, newState->nins)) {
+ /* With not too many arcs, just do them one at a time */
+ struct arc *a;
+
+ for (a = oldState->ins; a != NULL; a = a->inchain) {
cparc(nfa, a, a->from, newState);
}
+ } else {
+ /*
+ * With many arcs, use a sort-merge approach. Note that createarc()
+ * will put new arcs onto the front of newState's chain, so it does
+ * not break our walk through the sorted part of the chain.
+ */
+ struct arc *oa;
+ struct arc *na;
+
+ /*
+ * Because we bypass newarc() in this code path, we'd better include a
+ * cancel check.
+ */
+ if (CANCEL_REQUESTED(nfa->v->re)) {
+ NERR(REG_CANCEL);
+ return;
+ }
+
+ sortins(nfa, oldState);
+ sortins(nfa, newState);
+ if (NISERR()) {
+ return; /* might have failed to sort */
+ }
+ oa = oldState->ins;
+ na = newState->ins;
+ while (oa != NULL && na != NULL) {
+ struct arc *a = oa;
+
+ switch (sortins_cmp(&oa, &na)) {
+ case -1:
+ /* newState does not have anything matching oa */
+ oa = oa->inchain;
+ createarc(nfa, a->type, a->co, a->from, newState);
+ break;
+ case 0:
+ /* match, advance in both lists */
+ oa = oa->inchain;
+ na = na->inchain;
+ break;
+ case +1:
+ /* advance only na; oa might have a match later */
+ na = na->inchain;
+ break;
+ default:
+ assert(NOTREACHED);
+ }
+ }
+ while (oa != NULL) {
+ /* newState does not have anything matching oa */
+ struct arc *a = oa;
+
+ oa = oa->inchain;
+ createarc(nfa, a->type, a->co, a->from, newState);
+ }
+ }
+}
+
+/*
+ * mergeins - merge a list of inarcs into a state
+ *
+ * This is much like copyins, but the source arcs are listed in an array,
+ * and are not guaranteed unique. It's okay to clobber the array contents.
+ */
+static void
+mergeins(
+ struct nfa * nfa,
+ struct state * s,
+ struct arc ** arcarray,
+ int arccount)
+{
+ struct arc *na;
+ int i;
+ int j;
+
+ if (arccount <= 0) {
+ return;
+ }
+
+ /*
+ * Because we bypass newarc() in this code path, we'd better include a
+ * cancel check.
+ */
+ if (CANCEL_REQUESTED(nfa->v->re)) {
+ NERR(REG_CANCEL);
+ return;
+ }
+
+ /* Sort existing inarcs as well as proposed new ones */
+ sortins(nfa, s);
+ if (NISERR()) {
+ return; /* might have failed to sort */
+ }
+
+ qsort(arcarray, arccount, sizeof(struct arc *), sortins_cmp);
+
+ /*
+ * arcarray very likely includes dups, so we must eliminate them. (This
+ * could be folded into the next loop, but it's not worth the trouble.)
+ */
+ j = 0;
+ for (i = 1; i < arccount; i++) {
+ switch (sortins_cmp(&arcarray[j], &arcarray[i])) {
+ case -1:
+ /* non-dup */
+ arcarray[++j] = arcarray[i];
+ break;
+ case 0:
+ /* dup */
+ break;
+ default:
+ /* trouble */
+ assert(NOTREACHED);
+ }
+ }
+ arccount = j + 1;
+
+ /*
+ * Now merge into s' inchain. Note that createarc() will put new arcs
+ * onto the front of s's chain, so it does not break our walk through the
+ * sorted part of the chain.
+ */
+ i = 0;
+ na = s->ins;
+ while (i < arccount && na != NULL) {
+ struct arc *a = arcarray[i];
+
+ switch (sortins_cmp(&a, &na)) {
+ case -1:
+ /* s does not have anything matching a */
+ createarc(nfa, a->type, a->co, a->from, s);
+ i++;
+ break;
+ case 0:
+ /* match, advance in both lists */
+ i++;
+ na = na->inchain;
+ break;
+ case +1:
+ /* advance only na; array might have a match later */
+ na = na->inchain;
+ break;
+ default:
+ assert(NOTREACHED);
+ }
+ }
+ while (i < arccount) {
+ /* s does not have anything matching a */
+ struct arc *a = arcarray[i];
+
+ createarc(nfa, a->type, a->co, a->from, s);
+ i++;
}
}
@@ -648,36 +1024,153 @@ moveouts(
struct state *oldState,
struct state *newState)
{
- struct arc *a;
-
assert(oldState != newState);
- while ((a = oldState->outs) != NULL) {
- cparc(nfa, a, newState, a->to);
- freearc(nfa, a);
+ if (!BULK_ARC_OP_USE_SORT(oldState->nouts, newState->nouts)) {
+ /* With not too many arcs, just do them one at a time */
+ struct arc *a;
+
+ while ((a = oldState->outs) != NULL) {
+ cparc(nfa, a, newState, a->to);
+ freearc(nfa, a);
+ }
+ } else {
+ /*
+ * With many arcs, use a sort-merge approach. Note that createarc()
+ * will put new arcs onto the front of newState's chain, so it does
+ * not break our walk through the sorted part of the chain.
+ */
+ struct arc *oa;
+ struct arc *na;
+
+ /*
+ * Because we bypass newarc() in this code path, we'd better include a
+ * cancel check.
+ */
+ if (CANCEL_REQUESTED(nfa->v->re)) {
+ NERR(REG_CANCEL);
+ return;
+ }
+
+ sortouts(nfa, oldState);
+ sortouts(nfa, newState);
+ if (NISERR()) {
+ return; /* might have failed to sort */
+ }
+ oa = oldState->outs;
+ na = newState->outs;
+ while (oa != NULL && na != NULL) {
+ struct arc *a = oa;
+
+ switch (sortouts_cmp(&oa, &na)) {
+ case -1:
+ /* newState does not have anything matching oa */
+ oa = oa->outchain;
+ createarc(nfa, a->type, a->co, newState, a->to);
+ freearc(nfa, a);
+ break;
+ case 0:
+ /* match, advance in both lists */
+ oa = oa->outchain;
+ na = na->outchain;
+ /* ... and drop duplicate arc from oldState */
+ freearc(nfa, a);
+ break;
+ case +1:
+ /* advance only na; oa might have a match later */
+ na = na->outchain;
+ break;
+ default:
+ assert(NOTREACHED);
+ }
+ }
+ while (oa != NULL) {
+ /* newState does not have anything matching oa */
+ struct arc *a = oa;
+
+ oa = oa->outchain;
+ createarc(nfa, a->type, a->co, newState, a->to);
+ freearc(nfa, a);
+ }
}
+
+ assert(oldState->nouts == 0);
+ assert(oldState->outs == NULL);
}
/*
- 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 *, struct state *, struct state *, int);
*/
static void
copyouts(
struct nfa *nfa,
struct state *oldState,
- struct state *newState,
- int all)
+ struct state *newState)
{
- struct arc *a;
-
assert(oldState != newState);
- for (a=oldState->outs ; a!=NULL ; a=a->outchain) {
- if (all || a->type != EMPTY) {
+ if (!BULK_ARC_OP_USE_SORT(oldState->nouts, newState->nouts)) {
+ /* With not too many arcs, just do them one at a time */
+ struct arc *a;
+
+ for (a = oldState->outs; a != NULL; a = a->outchain) {
cparc(nfa, a, newState, a->to);
}
+ } else {
+ /*
+ * With many arcs, use a sort-merge approach. Note that createarc()
+ * will put new arcs onto the front of newState's chain, so it does
+ * not break our walk through the sorted part of the chain.
+ */
+ struct arc *oa;
+ struct arc *na;
+
+ /*
+ * Because we bypass newarc() in this code path, we'd better include a
+ * cancel check.
+ */
+ if (CANCEL_REQUESTED(nfa->v->re)) {
+ NERR(REG_CANCEL);
+ return;
+ }
+
+ sortouts(nfa, oldState);
+ sortouts(nfa, newState);
+ if (NISERR()) {
+ return; /* might have failed to sort */
+ }
+ oa = oldState->outs;
+ na = newState->outs;
+ while (oa != NULL && na != NULL) {
+ struct arc *a = oa;
+
+ switch (sortouts_cmp(&oa, &na)) {
+ case -1:
+ /* newState does not have anything matching oa */
+ oa = oa->outchain;
+ createarc(nfa, a->type, a->co, newState, a->to);
+ break;
+ case 0:
+ /* match, advance in both lists */
+ oa = oa->outchain;
+ na = na->outchain;
+ break;
+ case +1:
+ /* advance only na; oa might have a match later */
+ na = na->outchain;
+ break;
+ default:
+ assert(NOTREACHED);
+ }
+ }
+ while (oa != NULL) {
+ /* newState does not have anything matching oa */
+ struct arc *a = oa;
+
+ oa = oa->outchain;
+ createarc(nfa, a->type, a->co, newState, a->to);
+ }
}
}
@@ -883,6 +1376,20 @@ specialcolors(
- optimize - optimize an NFA
^ static long optimize(struct nfa *, FILE *);
*/
+
+ /*
+ * The main goal of this function is not so much "optimization" (though it
+ * does try to get rid of useless NFA states) as reducing the NFA to a form
+ * the regex executor can handle. The executor, and indeed the cNFA format
+ * that is its input, can only handle PLAIN and LACON arcs. The output of
+ * the regex parser also includes EMPTY (do-nothing) arcs, as well as
+ * ^, $, AHEAD, and BEHIND constraint arcs, which we must get rid of here.
+ * We first get rid of EMPTY arcs and then deal with the constraint arcs.
+ * The hardest part of either job is to get rid of circular loops of the
+ * target arc type. We would have to do that in any case, though, as such a
+ * loop would otherwise allow the executor to cycle through the loop endlessly
+ * without making any progress in the input string.
+ */
static long /* re_info bits */
optimize(
struct nfa *nfa,
@@ -904,17 +1411,23 @@ optimize(
if (verbose) {
fprintf(f, "\nconstraints:\n");
}
+ fixconstraintloops(nfa, f); /* get rid of constraint loops */
pullback(nfa, f); /* pull back constraints backward */
pushfwd(nfa, f); /* push fwd constraints forward */
if (verbose) {
fprintf(f, "\nfinal cleanup:\n");
}
cleanup(nfa); /* final tidying */
+#ifdef REG_DEBUG
+ if (verbose) {
+ dumpnfa(nfa, f);
+ }
+#endif
return analyze(nfa); /* and analysis */
}
/*
- - pullback - pull back constraints backward to (with luck) eliminate them
+ - pullback - pull back constraints backward to eliminate them
^ static VOID pullback(struct nfa *, FILE *);
*/
static void
@@ -926,6 +1439,7 @@ pullback(
struct state *nexts;
struct arc *a;
struct arc *nexta;
+ struct state *intermediates;
int progress;
/*
@@ -936,15 +1450,27 @@ pullback(
progress = 0;
for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) {
nexts = s->next;
+ intermediates = NULL;
for (a=s->outs ; a!=NULL && !NISERR() ; a=nexta) {
nexta = a->outchain;
if (a->type == '^' || a->type == BEHIND) {
- if (pull(nfa, a)) {
+ if (pull(nfa, a, &intermediates)) {
progress = 1;
}
}
assert(nexta == NULL || s->no != FREESTATE);
}
+ /* clear tmp fields of intermediate states created here */
+ while (intermediates != NULL) {
+ struct state *ns = intermediates->tmp;
+
+ intermediates->tmp = NULL;
+ intermediates = ns;
+ }
+ /* if s is now useless, get rid of it */
+ if ((s->nins == 0 || s->nouts == 0) && !s->flag) {
+ dropstate(nfa, s);
+ }
}
if (progress && f != NULL) {
dumpnfa(nfa, f);
@@ -954,6 +1480,12 @@ pullback(
return;
}
+ /*
+ * Any ^ constraints we were able to pull to the start state can now be
+ * replaced by PLAIN arcs referencing the BOS or BOL colors. There should
+ * be no other ^ or BEHIND arcs left in the NFA, though we do not check
+ * that here (compact() will fail if so).
+ */
for (a=nfa->pre->outs ; a!=NULL ; a=nexta) {
nexta = a->outchain;
if (a->type == '^') {
@@ -966,15 +1498,28 @@ pullback(
/*
- pull - pull a back constraint backward past its source state
- * A significant property of this function is that it deletes at most
- * one state -- the constraint's from state -- and only if the constraint
- * was that state's last outarc.
+ *
+ * Returns 1 if successful (which it always is unless the source is the
+ * start state or we have an internal error), 0 if nothing happened.
+ *
+ * A significant property of this function is that it deletes no pre-existing
+ * states, and no outarcs of the constraint's from state other than the given
+ * constraint arc. This makes the loops in pullback() safe, at the cost that
+ * we may leave useless states behind. Therefore, we leave it to pullback()
+ * to delete such states.
+ *
+ * If the from state has multiple back-constraint outarcs, and/or multiple
+ * compatible constraint inarcs, we only need to create one new intermediate
+ * state per combination of predecessor and successor states. *intermediates
+ * points to a list of such intermediate states for this from state (chained
+ * through their tmp fields).
^ static int pull(struct nfa *, struct arc *);
*/
-static int /* 0 couldn't, 1 could */
+static int
pull(
struct nfa *nfa,
- struct arc *con)
+ struct arc *con,
+ struct state **intermediates)
{
struct state *from = con->from;
struct state *to = con->to;
@@ -982,10 +1527,7 @@ pull(
struct arc *nexta;
struct state *s;
- if (from == to) { /* circular constraint is pointless */
- freearc(nfa, con);
- return 1;
- }
+ assert(from != to); /* should have gotten rid of this earlier */
if (from->flag) { /* can't pull back beyond start */
return 0;
}
@@ -995,26 +1537,9 @@ pull(
}
/*
- * DGP 2007-11-15: Cloning a state with a circular constraint on its list
- * of outs can lead to trouble [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.
+ * First, clone from state if necessary to avoid other outarcs. This may
+ * seem wasteful, but it simplifies the logic, and we'll get rid of the
+ * clone state again at the bottom.
*/
if (from->nouts > 1) {
@@ -1022,10 +1547,12 @@ pull(
if (NISERR()) {
return 0;
}
- assert(to != from); /* con is not an inarc */
- copyins(nfa, from, s, 1); /* duplicate inarcs */
+ copyins(nfa, from, s); /* duplicate inarcs */
cparc(nfa, con, s, to); /* move constraint arc */
freearc(nfa, con);
+ if (NISERR()) {
+ return 0;
+ }
from = s;
con = from->outs;
}
@@ -1035,7 +1562,7 @@ pull(
* Propagate the constraint into the from state's inarcs.
*/
- for (a=from->ins ; a!=NULL ; a=nexta) {
+ for (a=from->ins ; a!=NULL && !NISERR(); a=nexta) {
nexta = a->inchain;
switch (combine(con, a)) {
case INCOMPATIBLE: /* destroy the arc */
@@ -1044,17 +1571,25 @@ pull(
case SATISFIED: /* no action needed */
break;
case COMPATIBLE: /* swap the two arcs, more or less */
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
+ /* need an intermediate state, but might have one already */
+ for (s = *intermediates; s != NULL; s = s->tmp) {
+ assert(s->nins > 0 && s->nouts > 0);
+ if (s->ins->from == a->from && s->outs->to == to) {
+ break;
+ }
}
- cparc(nfa, a, s, to); /* anticipate move */
- cparc(nfa, con, a->from, s);
- if (NISERR()) {
- return 0;
+ if (s == NULL) {
+ s = newstate(nfa);
+ if (NISERR()) {
+ return 0;
+ }
+ s->tmp = *intermediates;
+ *intermediates = s;
}
- freearc(nfa, a);
- break;
+ cparc(nfa, con, a->from, s);
+ cparc(nfa, a, s, to);
+ freearc(nfa, a);
+ break;
default:
assert(NOTREACHED);
break;
@@ -1066,12 +1601,13 @@ pull(
*/
moveins(nfa, from, to);
- dropstate(nfa, from); /* will free the constraint */
+ freearc(nfa, con);
+ /* from state is now useless, but we leave it to pullback() to clean up */
return 1;
}
/*
- - pushfwd - push forward constraints forward to (with luck) eliminate them
+ - pushfwd - push forward constraints forward to eliminate them
^ static VOID pushfwd(struct nfa *, FILE *);
*/
static void
@@ -1083,6 +1619,7 @@ pushfwd(
struct state *nexts;
struct arc *a;
struct arc *nexta;
+ struct state *intermediates;
int progress;
/*
@@ -1093,14 +1630,25 @@ pushfwd(
progress = 0;
for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) {
nexts = s->next;
+ intermediates = NULL;
for (a = s->ins; a != NULL && !NISERR(); a = nexta) {
nexta = a->inchain;
if (a->type == '$' || a->type == AHEAD) {
- if (push(nfa, a)) {
+ if (push(nfa, a, &intermediates)) {
progress = 1;
}
}
- assert(nexta == NULL || s->no != FREESTATE);
+ }
+ /* clear tmp fields of intermediate states created here */
+ while (intermediates != NULL) {
+ struct state *ns = intermediates->tmp;
+
+ intermediates->tmp = NULL;
+ intermediates = ns;
+ }
+ /* if s is now useless, get rid of it */
+ if ((s->nins == 0 || s->nouts == 0) && !s->flag) {
+ dropstate(nfa, s);
}
}
if (progress && f != NULL) {
@@ -1111,6 +1659,12 @@ pushfwd(
return;
}
+ /*
+ * Any $ constraints we were able to push to the post state can now be
+ * replaced by PLAIN arcs referencing the EOS or EOL colors. There should
+ * be no other $ or AHEAD arcs left in the NFA, though we do not check
+ * that here (compact() will fail if so).
+ */
for (a = nfa->post->ins; a != NULL; a = nexta) {
nexta = a->inchain;
if (a->type == '$') {
@@ -1123,15 +1677,28 @@ pushfwd(
/*
- push - push a forward constraint forward past its destination state
- * A significant property of this function is that it deletes at most
- * one state -- the constraint's to state -- and only if the constraint
- * was that state's last inarc.
+ *
+ * Returns 1 if successful (which it always is unless the destination is the
+ * post state or we have an internal error), 0 if nothing happened.
+ *
+ * A significant property of this function is that it deletes no pre-existing
+ * states, and no inarcs of the constraint's to state other than the given
+ * constraint arc. This makes the loops in pushfwd() safe, at the cost that
+ * we may leave useless states behind. Therefore, we leave it to pushfwd()
+ * to delete such states.
+ *
+ * If the to state has multiple forward-constraint inarcs, and/or multiple
+ * compatible constraint outarcs, we only need to create one new intermediate
+ * state per combination of predecessor and successor states. *intermediates
+ * points to a list of such intermediate states for this to state (chained
+ * through their tmp fields).
^ static int push(struct nfa *, struct arc *);
*/
-static int /* 0 couldn't, 1 could */
+static int
push(
struct nfa *nfa,
- struct arc *con)
+ struct arc *con,
+ struct state **intermediates)
{
struct state *from = con->from;
struct state *to = con->to;
@@ -1139,10 +1706,7 @@ push(
struct arc *nexta;
struct state *s;
- if (to == from) { /* circular constraint is pointless */
- freearc(nfa, con);
- return 1;
- }
+ assert(to != from); /* should have gotten rid of this earlier */
if (to->flag) { /* can't push forward beyond end */
return 0;
}
@@ -1152,29 +1716,9 @@ push(
}
/*
- * 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.
+ * First, clone to state if necessary to avoid other inarcs. This may
+ * seem wasteful, but it simplifies the logic, and we'll get rid of the
+ * clone state again at the bottom.
*/
if (to->nins > 1) {
@@ -1182,9 +1726,12 @@ push(
if (NISERR()) {
return 0;
}
- copyouts(nfa, to, s, 1); /* duplicate outarcs */
- cparc(nfa, con, from, s); /* move constraint */
+ copyouts(nfa, to, s); /* duplicate outarcs */
+ cparc(nfa, con, from, s); /* move constraint arc */
freearc(nfa, con);
+ if (NISERR()) {
+ return 0;
+ }
to = s;
con = to->ins;
}
@@ -1194,7 +1741,7 @@ push(
* Propagate the constraint into the to state's outarcs.
*/
- for (a = to->outs; a != NULL; a = nexta) {
+ for (a = to->outs; a != NULL && !NISERR(); a = nexta) {
nexta = a->outchain;
switch (combine(con, a)) {
case INCOMPATIBLE: /* destroy the arc */
@@ -1203,17 +1750,25 @@ push(
case SATISFIED: /* no action needed */
break;
case COMPATIBLE: /* swap the two arcs, more or less */
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
+ /* need an intermediate state, but might have one already */
+ for (s = *intermediates; s != NULL; s = s->tmp) {
+ assert(s->nins > 0 && s->nouts > 0);
+ if (s->ins->from == from && s->outs->to == a->to) {
+ break;
+ }
}
- cparc(nfa, con, s, a->to); /* anticipate move */
- cparc(nfa, a, from, s);
- if (NISERR()) {
- return 0;
+ if (s == NULL) {
+ s = newstate(nfa);
+ if (NISERR()) {
+ return 0;
+ }
+ s->tmp = *intermediates;
+ *intermediates = s;
}
- freearc(nfa, a);
- break;
+ cparc(nfa, con, s, a->to);
+ cparc(nfa, a, from, s);
+ freearc(nfa, a);
+ break;
default:
assert(NOTREACHED);
break;
@@ -1225,7 +1780,8 @@ push(
*/
moveouts(nfa, to, from);
- dropstate(nfa, to); /* will free the constraint */
+ freearc(nfa, con);
+ /* to state is now useless, but we leave it to pushfwd() to clean up */
return 1;
}
@@ -1303,6 +1859,12 @@ fixempties(
struct state *nexts;
struct arc *a;
struct arc *nexta;
+ int totalinarcs;
+ struct arc **inarcsorig;
+ struct arc **arcarray;
+ int arccount;
+ int prevnins;
+ int nskip;
/*
* First, get rid of any states whose sole out-arc is an EMPTY,
@@ -1348,42 +1910,129 @@ fixempties(
dropstate(nfa, s);
}
+ if (NISERR()) {
+ return;
+ }
+
/*
- * 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.
+ * For each remaining NFA state, find all other states from which it is
+ * reachable by a chain of one or more EMPTY arcs. Then generate new arcs
+ * that eliminate the need for each such chain.
+ *
+ * We could replace a chain of EMPTY arcs that leads from a "from" state
+ * to a "to" state either by pushing non-EMPTY arcs forward (linking
+ * directly from "from"'s predecessors to "to") or by pulling them back
+ * (linking directly from "from" to "to"'s successors). We choose to
+ * always do the former; this choice is somewhat arbitrary, but the
+ * approach below requires that we uniformly do one or the other.
+ *
+ * Suppose we have a chain of N successive EMPTY arcs (where N can easily
+ * approach the size of the NFA). All of the intermediate states must
+ * have additional inarcs and outarcs, else they'd have been removed by
+ * the steps above. Assuming their inarcs are mostly not empties, we will
+ * add O(N^2) arcs to the NFA, since a non-EMPTY inarc leading to any one
+ * state in the chain must be duplicated to lead to all its successor
+ * states as well. So there is no hope of doing less than O(N^2) work;
+ * however, we should endeavor to keep the big-O cost from being even
+ * worse than that, which it can easily become without care. In
+ * particular, suppose we were to copy all S1's inarcs forward to S2, and
+ * then also to S3, and then later we consider pushing S2's inarcs forward
+ * to S3. If we include the arcs already copied from S1 in that, we'd be
+ * doing O(N^3) work. (The duplicate-arc elimination built into newarc()
+ * and its cohorts would get rid of the extra arcs, but not without cost.)
+ *
+ * We can avoid this cost by treating only arcs that existed at the start
+ * of this phase as candidates to be pushed forward. To identify those,
+ * we remember the first inarc each state had to start with. We rely on
+ * the fact that newarc() and friends put new arcs on the front of their
+ * to-states' inchains, and that this phase never deletes arcs, so that
+ * the original arcs must be the last arcs in their to-states' inchains.
*
- * 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.
+ * So the process here is that, for each state in the NFA, we gather up
+ * all non-EMPTY inarcs of states that can reach the target state via
+ * EMPTY arcs. We then sort, de-duplicate, and merge these arcs into the
+ * target state's inchain. (We can safely use sort-merge for this as long
+ * as we update each state's original-arcs pointer after we add arcs to
+ * it; the sort step of mergeins probably changed the order of the old
+ * arcs.)
+ *
+ * Another refinement worth making is that, because we only add non-EMPTY
+ * arcs during this phase, and all added arcs have the same from-state as
+ * the non-EMPTY arc they were cloned from, we know ahead of time that any
+ * states having only EMPTY outarcs will be useless for lack of outarcs
+ * after we drop the EMPTY arcs. (They cannot gain non-EMPTY outarcs if
+ * they had none to start with.) So we need not bother to update the
+ * inchains of such states at all.
+ */
+
+ /* Remember the states' first original inarcs */
+ /* ... and while at it, count how many old inarcs there are altogether */
+ inarcsorig = (struct arc **) MALLOC(nfa->nstates * sizeof(struct arc *));
+ if (inarcsorig == NULL) {
+ NERR(REG_ESPACE);
+ return;
+ }
+ totalinarcs = 0;
+ for (s = nfa->states; s != NULL; s = s->next) {
+ inarcsorig[s->no] = s->ins;
+ totalinarcs += s->nins;
+ }
+
+ /*
+ * Create a workspace for accumulating the inarcs to be added to the
+ * current target state. totalinarcs is probably a considerable
+ * overestimate of the space needed, but the NFA is unlikely to be large
+ * enough at this point to make it worth being smarter.
*/
+ arcarray = (struct arc **) MALLOC(totalinarcs * sizeof(struct arc *));
+ if (arcarray == NULL) {
+ NERR(REG_ESPACE);
+ FREE(inarcsorig);
+ return;
+ }
+
+ /* And iterate over the target states */
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);
- }
+ /* Ignore target states without non-EMPTY outarcs, per note above */
+ if (!s->flag && !hasnonemptyout(s)) {
+ continue;
+ }
- /* Reset the tmp fields as we walk back */
- nexts = s2->tmp;
- s2->tmp = NULL;
+ /* Find predecessor states and accumulate their original inarcs */
+ arccount = 0;
+ for (s2 = emptyreachable(nfa, s, s, inarcsorig); s2 != s; s2 = nexts) {
+ /* Add s2's original inarcs to arcarray[], but ignore empties */
+ for (a = inarcsorig[s2->no]; a != NULL; a = a->inchain) {
+ if (a->type != EMPTY) {
+ arcarray[arccount++] = a;
+ }
+ }
+
+ /* Reset the tmp fields as we walk back */
+ nexts = s2->tmp;
+ s2->tmp = NULL;
+ }
+ s->tmp = NULL;
+ assert(arccount <= totalinarcs);
+
+ /* Remember how many original inarcs this state has */
+ prevnins = s->nins;
+
+ /* Add non-duplicate inarcs to target state */
+ mergeins(nfa, s, arcarray, arccount);
+
+ /* Now we must update the state's inarcsorig pointer */
+ nskip = s->nins - prevnins;
+ a = s->ins;
+ while (nskip-- > 0) {
+ a = a->inchain;
}
- s->tmp = NULL;
+ inarcsorig[s->no] = a;
}
+
+ FREE(arcarray);
+ FREE(inarcsorig);
+
if (NISERR()) {
return;
}
@@ -1419,89 +2068,604 @@ fixempties(
}
/*
- - emptyreachable - recursively find all states reachable from s by EMPTY arcs
+ - emptyreachable - recursively find all states that can reach 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.
+ *
+ * Since this is only used in fixempties(), we pass in the inarcsorig[] array
+ * maintained by that function. This lets us skip over all new inarcs, which
+ * are certainly not EMPTY arcs.
+ *
* 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.
+ * the NFA, and in practice will be less than that.
^ static struct state *emptyreachable(struct state *, struct state *);
*/
static struct state *
emptyreachable(
+ struct nfa *nfa,
struct state *s,
- struct state *lastfound)
+ struct state *lastfound,
+ struct arc **inarcsorig)
{
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);
+ for (a = inarcsorig[s->no]; a != NULL; a = a->inchain) {
+ if (a->type == EMPTY && a->from->tmp == NULL) {
+ lastfound = emptyreachable(nfa, a->from, lastfound, inarcsorig);
}
}
return lastfound;
}
-
+
+/*
+ * isconstraintarc - detect whether an arc is of a constraint type
+ */
+static inline int
+isconstraintarc(struct arc * a)
+{
+ switch (a->type)
+ {
+ case '^':
+ case '$':
+ case BEHIND:
+ case AHEAD:
+ case LACON:
+ return 1;
+ }
+ return 0;
+}
+
/*
- - 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 *, struct state *, struct state *);
+ * hasconstraintout - does state have a constraint out arc?
+ */
+static int
+hasconstraintout(struct state * s)
+{
+ struct arc *a;
+
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (isconstraintarc(a)) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+ * fixconstraintloops - get rid of loops containing only constraint arcs
+ *
+ * A loop of states that contains only constraint arcs is useless, since
+ * passing around the loop represents no forward progress. Moreover, it
+ * would cause infinite looping in pullback/pushfwd, so we need to get rid
+ * of such loops before doing that.
*/
static void
-replaceempty(
- struct nfa *nfa,
- struct state *from,
- struct state *to)
+fixconstraintloops(
+ struct nfa * nfa,
+ FILE *f) /* for debug output; NULL none */
{
- int fromouts;
- int toins;
+ struct state *s;
+ struct state *nexts;
+ struct arc *a;
+ struct arc *nexta;
+ int hasconstraints;
+
+ /*
+ * In the trivial case of a state that loops to itself, we can just drop
+ * the constraint arc altogether. This is worth special-casing because
+ * such loops are far more common than loops containing multiple states.
+ * While we're at it, note whether any constraint arcs survive.
+ */
+ hasconstraints = 0;
+ 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);
+ for (a = s->outs; a != NULL && !NISERR(); a = nexta) {
+ nexta = a->outchain;
+ if (isconstraintarc(a)) {
+ if (a->to == s) {
+ freearc(nfa, a);
+ } else {
+ hasconstraints = 1;
+ }
+ }
+ }
+ /* If we removed all the outarcs, the state is useless. */
+ if (s->nouts == 0 && !s->flag) {
+ dropstate(nfa, s);
+ }
+ }
+
+ /* Nothing to do if no remaining constraint arcs */
+ if (NISERR() || !hasconstraints) {
+ return;
+ }
+
+ /*
+ * Starting from each remaining NFA state, search outwards for a
+ * constraint loop. If we find a loop, break the loop, then start the
+ * search over. (We could possibly retain some state from the first scan,
+ * but it would complicate things greatly, and multi-state constraint
+ * loops are rare enough that it's not worth optimizing the case.)
+ */
+ restart:
+ for (s = nfa->states; s != NULL && !NISERR(); s = s->next) {
+ if (findconstraintloop(nfa, s)) {
+ goto restart;
+ }
+ }
- assert(from != to);
+ if (NISERR()) {
+ return;
+ }
/*
- * 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.
+ * Now 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.)
*
- * 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 copynonemptyins path in that case.
+ * Because findconstraintloop intentionally doesn't reset all tmp fields,
+ * we have to clear them after it's done. This is a convenient place to
+ * do that, too.
+ */
+ for (s = nfa->states; s != NULL; s = nexts) {
+ nexts = s->next;
+ s->tmp = NULL;
+ if ((s->nins == 0 || s->nouts == 0) && !s->flag) {
+ dropstate(nfa, s);
+ }
+ }
+
+ if (f != NULL) {
+ dumpnfa(nfa, f);
+ }
+}
+
+/*
+ * findconstraintloop - recursively find a loop of constraint arcs
+ *
+ * If we find a loop, break it by calling breakconstraintloop(), then
+ * return 1; otherwise return 0.
+ *
+ * State tmp fields are guaranteed all NULL on a success return, because
+ * breakconstraintloop does that. After a failure return, any state that
+ * is known not to be part of a loop is marked with s->tmp == s; this allows
+ * us not to have to re-prove that fact on later calls. (This convention is
+ * workable because we already eliminated single-state loops.)
+ *
+ * Note that the found loop doesn't necessarily include the first state we
+ * are called on. Any loop reachable from that state will do.
+ *
+ * The maximum recursion depth here is one more than the length of the longest
+ * loop-free chain of constraint arcs, which is surely no more than the size
+ * of the NFA, and in practice will be a lot less than that.
+ */
+static int
+findconstraintloop(struct nfa * nfa, struct state * s)
+{
+ struct arc *a;
+
+ /* Since this is recursive, it could be driven to stack overflow */
+ if (STACK_TOO_DEEP(nfa->v->re)) {
+ NERR(REG_ETOOBIG);
+ return 1; /* to exit as quickly as possible */
+ }
+
+ if (s->tmp != NULL) {
+ /* Already proven uninteresting? */
+ if (s->tmp == s) {
+ return 0;
+ }
+ /* Found a loop involving s */
+ breakconstraintloop(nfa, s);
+ /* The tmp fields have been cleaned up by breakconstraintloop */
+ return 1;
+ }
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (isconstraintarc(a)) {
+ struct state *sto = a->to;
+
+ assert(sto != s);
+ s->tmp = sto;
+ if (findconstraintloop(nfa, sto)) {
+ return 1;
+ }
+ }
+ }
+
+ /*
+ * If we get here, no constraint loop exists leading out from s. Mark it
+ * with s->tmp == s so we need not rediscover that fact again later.
+ */
+ s->tmp = s;
+ return 0;
+}
+
+/*
+ * breakconstraintloop - break a loop of constraint arcs
+ *
+ * sinitial is any one member state of the loop. Each loop member's tmp
+ * field links to its successor within the loop. (Note that this function
+ * will reset all the tmp fields to NULL.)
+ *
+ * We can break the loop by, for any one state S1 in the loop, cloning its
+ * loop successor state S2 (and possibly following states), and then moving
+ * all S1->S2 constraint arcs to point to the cloned S2. The cloned S2 should
+ * copy any non-constraint outarcs of S2. Constraint outarcs should be
+ * dropped if they point back to S1, else they need to be copied as arcs to
+ * similarly cloned states S3, S4, etc. In general, each cloned state copies
+ * non-constraint outarcs, drops constraint outarcs that would lead to itself
+ * or any earlier cloned state, and sends other constraint outarcs to newly
+ * cloned states. No cloned state will have any inarcs that aren't constraint
+ * arcs or do not lead from S1 or earlier-cloned states. It's okay to drop
+ * constraint back-arcs since they would not take us to any state we've not
+ * already been in; therefore, no new constraint loop is created. In this way
+ * we generate a modified NFA that can still represent every useful state
+ * sequence, but not sequences that represent state loops with no consumption
+ * of input data. Note that the set of cloned states will certainly include
+ * all of the loop member states other than S1, and it may also include
+ * non-loop states that are reachable from S2 via constraint arcs. This is
+ * important because there is no guarantee that findconstraintloop found a
+ * maximal loop (and searching for one would be NP-hard, so don't try).
+ * Frequently the "non-loop states" are actually part of a larger loop that
+ * we didn't notice, and indeed there may be several overlapping loops.
+ * This technique ensures convergence in such cases, while considering only
+ * the originally-found loop does not.
+ *
+ * If there is only one S1->S2 constraint arc, then that constraint is
+ * certainly satisfied when we enter any of the clone states. This means that
+ * in the common case where many of the constraint arcs are identically
+ * labeled, we can merge together clone states linked by a similarly-labeled
+ * constraint: if we can get to the first one we can certainly get to the
+ * second, so there's no need to distinguish. This greatly reduces the number
+ * of new states needed, so we preferentially break the given loop at a state
+ * pair where this is true.
+ *
+ * Furthermore, it's fairly common to find that a cloned successor state has
+ * no outarcs, especially if we're a bit aggressive about removing unnecessary
+ * outarcs. If that happens, then there is simply not any interesting state
+ * that can be reached through the predecessor's loop arcs, which means we can
+ * break the loop just by removing those loop arcs, with no new states added.
+ */
+static void
+breakconstraintloop(struct nfa * nfa, struct state * sinitial)
+{
+ struct state *s;
+ struct state *shead;
+ struct state *stail;
+ struct state *sclone;
+ struct state *nexts;
+ struct arc *refarc;
+ struct arc *a;
+ struct arc *nexta;
+
+ /*
+ * Start by identifying which loop step we want to break at.
+ * Preferentially this is one with only one constraint arc. (XXX are
+ * there any other secondary heuristics we want to use here?) Set refarc
+ * to point to the selected lone constraint arc, if there is one.
+ */
+ refarc = NULL;
+ s = sinitial;
+ do {
+ nexts = s->tmp;
+ assert(nexts != s); /* should not see any one-element loops */
+ if (refarc == NULL) {
+ int narcs = 0;
+
+ for (a = s->outs; a != NULL; a = a->outchain) {
+ if (a->to == nexts && isconstraintarc(a)) {
+ refarc = a;
+ narcs++;
+ }
+ }
+ assert(narcs > 0);
+ if (narcs > 1) {
+ refarc = NULL; /* multiple constraint arcs here, no good */
+ }
+ }
+ s = nexts;
+ } while (s != sinitial);
+
+ if (refarc) {
+ /* break at the refarc */
+ shead = refarc->from;
+ stail = refarc->to;
+ assert(stail == shead->tmp);
+ } else {
+ /* for lack of a better idea, break after sinitial */
+ shead = sinitial;
+ stail = sinitial->tmp;
+ }
+
+ /*
+ * Reset the tmp fields so that we can use them for local storage in
+ * clonesuccessorstates. (findconstraintloop won't mind, since it's just
+ * going to abandon its search anyway.)
*/
- fromouts = nonemptyouts(from);
- toins = (fromouts == 0) ? 1 : nonemptyins(to);
+ for (s = nfa->states; s != NULL; s = s->next) {
+ s->tmp = NULL;
+ }
- if (fromouts > toins) {
- copyouts(nfa, to, from, 0);
+ /*
+ * Recursively build clone state(s) as needed.
+ */
+ sclone = newstate(nfa);
+ if (sclone == NULL) {
+ assert(NISERR());
return;
}
- if (fromouts < toins) {
- copyins(nfa, from, to, 0);
+
+ clonesuccessorstates(nfa, stail, sclone, shead, refarc,
+ NULL, NULL, nfa->nstates);
+
+ if (NISERR()) {
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.
+ * It's possible that sclone has no outarcs at all, in which case it's
+ * useless. (We don't try extremely hard to get rid of useless states
+ * here, but this is an easy and fairly common case.)
*/
- if (from->nins > to->nouts) {
- copyouts(nfa, to, from, 0);
+ if (sclone->nouts == 0) {
+ freestate(nfa, sclone);
+ sclone = NULL;
+ }
+
+ /*
+ * Move shead's constraint-loop arcs to point to sclone, or just drop them
+ * if we discovered we don't need sclone.
+ */
+ for (a = shead->outs; a != NULL; a = nexta) {
+ nexta = a->outchain;
+ if (a->to == stail && isconstraintarc(a)) {
+ if (sclone) {
+ cparc(nfa, a, shead, sclone);
+ }
+ freearc(nfa, a);
+ if (NISERR()) {
+ break;
+ }
+ }
+ }
+}
+
+/*
+ * clonesuccessorstates - create a tree of constraint-arc successor states
+ *
+ * ssource is the state to be cloned, and sclone is the state to copy its
+ * outarcs into. sclone's inarcs, if any, should already be set up.
+ *
+ * spredecessor is the original predecessor state that we are trying to build
+ * successors for (it may not be the immediate predecessor of ssource).
+ * refarc, if not NULL, is the original constraint arc that is known to have
+ * been traversed out of spredecessor to reach the successor(s).
+ *
+ * For each cloned successor state, we transiently create a "donemap" that is
+ * a boolean array showing which source states we've already visited for this
+ * clone state. This prevents infinite recursion as well as useless repeat
+ * visits to the same state subtree (which can add up fast, since typical NFAs
+ * have multiple redundant arc pathways). Each donemap is a char array
+ * indexed by state number. The donemaps are all of the same size "nstates",
+ * which is nfa->nstates as of the start of the recursion. This is enough to
+ * have entries for all pre-existing states, but *not* entries for clone
+ * states created during the recursion. That's okay since we have no need to
+ * mark those.
+ *
+ * curdonemap is NULL when recursing to a new sclone state, or sclone's
+ * donemap when we are recursing without having created a new state (which we
+ * do when we decide we can merge a successor state into the current clone
+ * state). outerdonemap is NULL at the top level and otherwise the parent
+ * clone state's donemap.
+ *
+ * The successor states we create and fill here form a strict tree structure,
+ * with each state having exactly one predecessor, except that the toplevel
+ * state has no inarcs as yet (breakconstraintloop will add its inarcs from
+ * spredecessor after we're done). Thus, we can examine sclone's inarcs back
+ * to the root, plus refarc if any, to identify the set of constraints already
+ * known valid at the current point. This allows us to avoid generating extra
+ * successor states.
+ */
+static void
+clonesuccessorstates(
+ struct nfa * nfa,
+ struct state * ssource,
+ struct state * sclone,
+ struct state * spredecessor,
+ struct arc * refarc,
+ char *curdonemap,
+ char *outerdonemap,
+ int nstates)
+{
+ char *donemap;
+ struct arc *a;
+
+ /* Since this is recursive, it could be driven to stack overflow */
+ if (STACK_TOO_DEEP(nfa->v->re)) {
+ NERR(REG_ETOOBIG);
return;
}
- copyins(nfa, from, to, 0);
+ /* If this state hasn't already got a donemap, create one */
+ donemap = curdonemap;
+ if (donemap == NULL) {
+ donemap = (char *) MALLOC(nstates * sizeof(char));
+ if (donemap == NULL) {
+ NERR(REG_ESPACE);
+ return;
+ }
+
+ if (outerdonemap != NULL) {
+ /*
+ * Not at outermost recursion level, so copy the outer level's
+ * donemap; this ensures that we see states in process of being
+ * visited at outer levels, or already merged into predecessor
+ * states, as ones we shouldn't traverse back to.
+ */
+ memcpy(donemap, outerdonemap, nstates * sizeof(char));
+ } else {
+ /* At outermost level, only spredecessor is off-limits */
+ memset(donemap, 0, nstates * sizeof(char));
+ assert(spredecessor->no < nstates);
+ donemap[spredecessor->no] = 1;
+ }
+ }
+
+ /* Mark ssource as visited in the donemap */
+ assert(ssource->no < nstates);
+ assert(donemap[ssource->no] == 0);
+ donemap[ssource->no] = 1;
+
+ /*
+ * We proceed by first cloning all of ssource's outarcs, creating new
+ * clone states as needed but not doing more with them than that. Then in
+ * a second pass, recurse to process the child clone states. This allows
+ * us to have only one child clone state per reachable source state, even
+ * when there are multiple outarcs leading to the same state. Also, when
+ * we do visit a child state, its set of inarcs is known exactly, which
+ * makes it safe to apply the constraint-is-already-checked optimization.
+ * Also, this ensures that we've merged all the states we can into the
+ * current clone before we recurse to any children, thus possibly saving
+ * them from making extra images of those states.
+ *
+ * While this function runs, child clone states of the current state are
+ * marked by setting their tmp fields to point to the original state they
+ * were cloned from. This makes it possible to detect multiple outarcs
+ * leading to the same state, and also makes it easy to distinguish clone
+ * states from original states (which will have tmp == NULL).
+ */
+ for (a = ssource->outs; a != NULL && !NISERR(); a = a->outchain) {
+ struct state *sto = a->to;
+
+ /*
+ * We do not consider cloning successor states that have no constraint
+ * outarcs; just link to them as-is. They cannot be part of a
+ * constraint loop so there is no need to make copies. In particular,
+ * this rule keeps us from trying to clone the post state, which would
+ * be a bad idea.
+ */
+ if (isconstraintarc(a) && hasconstraintout(sto)) {
+ struct state *prevclone;
+ int canmerge;
+ struct arc *a2;
+
+ /*
+ * Back-link constraint arcs must not be followed. Nor is there a
+ * need to revisit states previously merged into this clone.
+ */
+ assert(sto->no < nstates);
+ if (donemap[sto->no] != 0) {
+ continue;
+ }
+
+ /*
+ * Check whether we already have a child clone state for this
+ * source state.
+ */
+ prevclone = NULL;
+ for (a2 = sclone->outs; a2 != NULL; a2 = a2->outchain) {
+ if (a2->to->tmp == sto) {
+ prevclone = a2->to;
+ break;
+ }
+ }
+
+ /*
+ * If this arc is labeled the same as refarc, or the same as any
+ * arc we must have traversed to get to sclone, then no additional
+ * constraints need to be met to get to sto, so we should just
+ * merge its outarcs into sclone.
+ */
+ if (refarc && a->type == refarc->type && a->co == refarc->co) {
+ canmerge = 1;
+ } else {
+ struct state *s;
+
+ canmerge = 0;
+ for (s = sclone; s->ins; s = s->ins->from) {
+ if (s->nins == 1 &&
+ a->type == s->ins->type && a->co == s->ins->co) {
+ canmerge = 1;
+ break;
+ }
+ }
+ }
+
+ if (canmerge) {
+ /*
+ * We can merge into sclone. If we previously made a child
+ * clone state, drop it; there's no need to visit it. (This
+ * can happen if ssource has multiple pathways to sto, and we
+ * only just now found one that is provably a no-op.)
+ */
+ if (prevclone) {
+ dropstate(nfa, prevclone); /* kills our outarc, too */
+ }
+
+ /* Recurse to merge sto's outarcs into sclone */
+ clonesuccessorstates(nfa, sto, sclone, spredecessor, refarc,
+ donemap, outerdonemap, nstates);
+ /* sto should now be marked as previously visited */
+ assert(NISERR() || donemap[sto->no] == 1);
+ } else if (prevclone) {
+ /*
+ * We already have a clone state for this successor, so just
+ * make another arc to it.
+ */
+ cparc(nfa, a, sclone, prevclone);
+ } else {
+ /*
+ * We need to create a new successor clone state.
+ */
+ struct state *stoclone;
+
+ stoclone = newstate(nfa);
+ if (stoclone == NULL) {
+ assert(NISERR());
+ break;
+ }
+ /* Mark it as to what it's a clone of */
+ stoclone->tmp = sto;
+ /* ... and add the outarc leading to it */
+ cparc(nfa, a, sclone, stoclone);
+ }
+ } else {
+ /*
+ * Non-constraint outarcs just get copied to sclone, as do outarcs
+ * leading to states with no constraint outarc.
+ */
+ cparc(nfa, a, sclone, sto);
+ }
+ }
+
+ /*
+ * If we are at outer level for this clone state, recurse to all its child
+ * clone states, clearing their tmp fields as we go. (If we're not
+ * outermost for sclone, leave this to be done by the outer call level.)
+ * Note that if we have multiple outarcs leading to the same clone state,
+ * it will only be recursed-to once.
+ */
+ if (curdonemap == NULL) {
+ for (a = sclone->outs; a != NULL && !NISERR(); a = a->outchain) {
+ struct state *stoclone = a->to;
+ struct state *sto = stoclone->tmp;
+
+ if (sto != NULL) {
+ stoclone->tmp = NULL;
+ clonesuccessorstates(nfa, sto, stoclone, spredecessor, refarc,
+ NULL, donemap, nstates);
+ }
+ }
+
+ /* Don't forget to free sclone's donemap when done with it */
+ FREE(donemap);
+ }
}
/*
@@ -1618,7 +2782,7 @@ analyze(
}
/*
- - compact - compact an NFA
+ - compact - construct the compact representation of an NFA
^ static VOID compact(struct nfa *, struct cnfa *);
*/
static void
@@ -1687,11 +2851,11 @@ compact(
cnfa->flags |= HASLACONS;
break;
default:
- assert(NOTREACHED);
+ NERR(REG_ASSERT);
break;
}
}
- carcsort(first, ca-1);
+ carcsort(first, ca - first);
ca->co = COLORLESS;
ca->to = 0;
ca++;
@@ -1711,33 +2875,39 @@ compact(
/*
- carcsort - sort compacted-NFA arcs by color
- * 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 *, struct carc *);
*/
static void
carcsort(
struct carc *first,
- struct carc *last)
+ size_t n)
{
- struct carc *p;
- struct carc *q;
- struct carc tmp;
-
- if (last - first <= 1) {
- return;
+ if (n > 1) {
+ qsort(first, n, sizeof(struct carc), carc_cmp);
}
+}
- 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 int
+carc_cmp(
+ const void *a,
+ const void *b)
+{
+ const struct carc *aa = (const struct carc *) a;
+ const struct carc *bb = (const struct carc *) b;
+
+ if (aa->co < bb->co) {
+ return -1;
+ }
+ if (aa->co > bb->co) {
+ return +1;
+ }
+ if (aa->to < bb->to) {
+ return -1;
+ }
+ if (aa->to > bb->to) {
+ return +1;
}
+ return 0;
}
/*
@@ -1765,6 +2935,8 @@ dumpnfa(
{
#ifdef REG_DEBUG
struct state *s;
+ int nstates = 0;
+ int narcs = 0;
fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no);
if (nfa->bos[0] != COLORLESS) {
@@ -1782,7 +2954,10 @@ dumpnfa(
fprintf(f, "\n");
for (s = nfa->states; s != NULL; s = s->next) {
dumpstate(s, f);
+ nstates++;
+ narcs += s->nouts;
}
+ fprintf(f, "total of %d states, %d arcs\n", nstates, narcs);
if (nfa->parent == NULL) {
dumpcolors(nfa->cm, f);
}
@@ -1835,37 +3010,28 @@ dumparcs(
FILE *f)
{
int pos;
+ struct arc *a;
- 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 dumprarcs(struct arc *, struct state *, FILE *, int);
- */
-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);
+ /* printing oldest arcs first is usually clearer */
+ a = s->outs;
+ assert(a != NULL);
+ while (a->outchain != NULL) {
+ a = a->outchain;
}
- dumparc(a, s, f);
- if (pos == 5) {
+ pos = 1;
+ do {
+ dumparc(a, s, f);
+ if (pos == 5) {
+ fprintf(f, "\n");
+ pos = 1;
+ } else {
+ pos++;
+ }
+ a = a->outchainRev;
+ } while (a != NULL);
+ if (pos != 1) {
fprintf(f, "\n");
- pos = 1;
- } else {
- pos++;
}
- return pos;
}
/*
generated by cgit v0.12 at 2024-11-05 03:25:27 (GMT)