diff options
| -rw-r--r-- | generic/rege_dfa.c | 1354 |
1 files changed, 677 insertions, 677 deletions
diff --git a/generic/rege_dfa.c b/generic/rege_dfa.c index 24ff2db..1628150 100644 --- a/generic/rege_dfa.c +++ b/generic/rege_dfa.c @@ -1,677 +1,677 @@ -/*
- * DFA routines
- * This file is #included by regexec.c.
- *
- * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
- *
- * Development of this software was funded, in part, by Cray Research Inc.,
- * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
- * Corporation, none of whom are responsible for the results. The author
- * thanks all of them.
- *
- * Redistribution and use in source and binary forms -- with or without
- * modification -- are permitted for any purpose, provided that
- * redistributions in source form retain this entire copyright notice and
- * indicate the origin and nature of any modifications.
- *
- * I'd appreciate being given credit for this package in the documentation
- * of software which uses it, but that is not a requirement.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
- * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
- * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-/*
- - longest - longest-preferred matching engine
- ^ static chr *longest(struct vars *, struct dfa *, chr *, chr *, int *);
- */
-static chr * /* endpoint, or NULL */
-longest(v, d, start, stop, hitstopp)
-struct vars *v; /* used only for debug and exec flags */
-struct dfa *d;
-chr *start; /* where the match should start */
-chr *stop; /* match must end at or before here */
-int *hitstopp; /* record whether hit v->stop, if non-NULL */
-{
- chr *cp;
- chr *realstop = (stop == v->stop) ? stop : stop + 1;
- color co;
- struct sset *css;
- struct sset *ss;
- chr *post;
- int i;
- struct colormap *cm = d->cm;
-
- /* initialize */
- css = initialize(v, d, start);
- cp = start;
- if (hitstopp != NULL)
- *hitstopp = 0;
-
- /* startup */
- FDEBUG(("+++ startup +++\n"));
- if (cp == v->start) {
- co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1];
- FDEBUG(("color %ld\n", (long)co));
- } else {
- co = GETCOLOR(cm, *(cp - 1));
- FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co));
- }
- css = miss(v, d, css, co, cp, start);
- if (css == NULL)
- return NULL;
- css->lastseen = cp;
-
- /* main loop */
- if (v->eflags®_FTRACE)
- while (cp < realstop) {
- FDEBUG(("+++ at c%d +++\n", css - d->ssets));
- co = GETCOLOR(cm, *cp);
- FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co));
- ss = css->outs[co];
- if (ss == NULL) {
- ss = miss(v, d, css, co, cp+1, start);
- if (ss == NULL)
- break; /* NOTE BREAK OUT */
- }
- cp++;
- ss->lastseen = cp;
- css = ss;
- }
- else
- while (cp < realstop) {
- co = GETCOLOR(cm, *cp);
- ss = css->outs[co];
- if (ss == NULL) {
- ss = miss(v, d, css, co, cp+1, start);
- if (ss == NULL)
- break; /* NOTE BREAK OUT */
- }
- cp++;
- ss->lastseen = cp;
- css = ss;
- }
-
- /* shutdown */
- FDEBUG(("+++ shutdown at c%d +++\n", css - d->ssets));
- if (cp == v->stop && stop == v->stop) {
- if (hitstopp != NULL)
- *hitstopp = 1;
- co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1];
- FDEBUG(("color %ld\n", (long)co));
- ss = miss(v, d, css, co, cp, start);
- /* special case: match ended at eol? */
- if (ss != NULL && (ss->flags&POSTSTATE))
- return cp;
- else if (ss != NULL)
- ss->lastseen = cp; /* to be tidy */
- }
-
- /* find last match, if any */
- post = d->lastpost;
- for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--)
- if ((ss->flags&POSTSTATE) && post != ss->lastseen &&
- (post == NULL || post < ss->lastseen))
- post = ss->lastseen;
- if (post != NULL) /* found one */
- return post - 1;
-
- return NULL;
-}
-
-/*
- - shortest - shortest-preferred matching engine
- ^ static chr *shortest(struct vars *, struct dfa *, chr *, chr *, chr *,
- ^ chr **, int *);
- */
-static chr * /* endpoint, or NULL */
-shortest(v, d, start, min, max, coldp, hitstopp)
-struct vars *v;
-struct dfa *d;
-chr *start; /* where the match should start */
-chr *min; /* match must end at or after here */
-chr *max; /* match must end at or before here */
-chr **coldp; /* store coldstart pointer here, if nonNULL */
-int *hitstopp; /* record whether hit v->stop, if non-NULL */
-{
- chr *cp;
- chr *realmin = (min == v->stop) ? min : min + 1;
- chr *realmax = (max == v->stop) ? max : max + 1;
- color co;
- struct sset *css;
- struct sset *ss;
- struct colormap *cm = d->cm;
-
- /* initialize */
- css = initialize(v, d, start);
- cp = start;
- if (hitstopp != NULL)
- *hitstopp = 0;
-
- /* startup */
- FDEBUG(("--- startup ---\n"));
- if (cp == v->start) {
- co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1];
- FDEBUG(("color %ld\n", (long)co));
- } else {
- co = GETCOLOR(cm, *(cp - 1));
- FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co));
- }
- css = miss(v, d, css, co, cp, start);
- if (css == NULL)
- return NULL;
- css->lastseen = cp;
- ss = css;
-
- /* main loop */
- if (v->eflags®_FTRACE)
- while (cp < realmax) {
- FDEBUG(("--- at c%d ---\n", css - d->ssets));
- co = GETCOLOR(cm, *cp);
- FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co));
- ss = css->outs[co];
- if (ss == NULL) {
- ss = miss(v, d, css, co, cp+1, start);
- if (ss == NULL)
- break; /* NOTE BREAK OUT */
- }
- cp++;
- ss->lastseen = cp;
- css = ss;
- if ((ss->flags&POSTSTATE) && cp >= realmin)
- break; /* NOTE BREAK OUT */
- }
- else
- while (cp < realmax) {
- co = GETCOLOR(cm, *cp);
- ss = css->outs[co];
- if (ss == NULL) {
- ss = miss(v, d, css, co, cp+1, start);
- if (ss == NULL)
- break; /* NOTE BREAK OUT */
- }
- cp++;
- ss->lastseen = cp;
- css = ss;
- if ((ss->flags&POSTSTATE) && cp >= realmin)
- break; /* NOTE BREAK OUT */
- }
-
- if (ss == NULL)
- return NULL;
-
- if (coldp != NULL) /* report last no-progress state set, if any */
- *coldp = lastcold(v, d);
-
- if ((ss->flags&POSTSTATE) && cp > min) {
- assert(cp >= realmin);
- cp--;
- } else if (cp == v->stop && max == v->stop) {
- co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1];
- FDEBUG(("color %ld\n", (long)co));
- ss = miss(v, d, css, co, cp, start);
- /* match might have ended at eol */
- if ((ss == NULL || !(ss->flags&POSTSTATE)) && hitstopp != NULL)
- *hitstopp = 1;
- }
-
- if (ss == NULL || !(ss->flags&POSTSTATE))
- return NULL;
-
- return cp;
-}
-
-/*
- - lastcold - determine last point at which no progress had been made
- ^ static chr *lastcold(struct vars *, struct dfa *);
- */
-static chr * /* endpoint, or NULL */
-lastcold(v, d)
-struct vars *v;
-struct dfa *d;
-{
- struct sset *ss;
- chr *nopr;
- int i;
-
- nopr = d->lastnopr;
- if (nopr == NULL)
- nopr = v->start;
- for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--)
- if ((ss->flags&NOPROGRESS) && nopr < ss->lastseen)
- nopr = ss->lastseen;
- return nopr;
-}
-
-/*
- - newdfa - set up a fresh DFA
- ^ static struct dfa *newdfa(struct vars *, struct cnfa *,
- ^ struct colormap *, struct smalldfa *);
- */
-static struct dfa *
-newdfa(v, cnfa, cm, small)
-struct vars *v;
-struct cnfa *cnfa;
-struct colormap *cm;
-struct smalldfa *small; /* preallocated space, may be NULL */
-{
- struct dfa *d;
- size_t nss = cnfa->nstates * 2;
- int wordsper = (cnfa->nstates + UBITS - 1) / UBITS;
- struct smalldfa *smallwas = small;
-
- assert(cnfa != NULL && cnfa->nstates != 0);
-
- if (nss <= FEWSTATES && cnfa->ncolors <= FEWCOLORS) {
- assert(wordsper == 1);
- if (small == NULL) {
- small = (struct smalldfa *)MALLOC(
- sizeof(struct smalldfa));
- if (small == NULL) {
- ERR(REG_ESPACE);
- return NULL;
- }
- }
- d = &small->dfa;
- d->ssets = small->ssets;
- d->statesarea = small->statesarea;
- d->work = &d->statesarea[nss];
- d->outsarea = small->outsarea;
- d->incarea = small->incarea;
- d->cptsmalloced = 0;
- d->mallocarea = (smallwas == NULL) ? (char *)small : NULL;
- } else {
- d = (struct dfa *)MALLOC(sizeof(struct dfa));
- if (d == NULL) {
- ERR(REG_ESPACE);
- return NULL;
- }
- d->ssets = (struct sset *)MALLOC(nss * sizeof(struct sset));
- d->statesarea = (unsigned *)MALLOC((nss+WORK) * wordsper *
- sizeof(unsigned));
- d->work = &d->statesarea[nss * wordsper];
- d->outsarea = (struct sset **)MALLOC(nss * cnfa->ncolors *
- sizeof(struct sset *));
- d->incarea = (struct arcp *)MALLOC(nss * cnfa->ncolors *
- sizeof(struct arcp));
- d->cptsmalloced = 1;
- d->mallocarea = (char *)d;
- if (d->ssets == NULL || d->statesarea == NULL ||
- d->outsarea == NULL || d->incarea == NULL) {
- freedfa(d);
- ERR(REG_ESPACE);
- return NULL;
- }
- }
-
- d->nssets = (v->eflags®_SMALL) ? 7 : nss;
- d->nssused = 0;
- d->nstates = cnfa->nstates;
- d->ncolors = cnfa->ncolors;
- d->wordsper = wordsper;
- d->cnfa = cnfa;
- d->cm = cm;
- d->lastpost = NULL;
- d->lastnopr = NULL;
- d->search = d->ssets;
-
- /* initialization of sset fields is done as needed */
-
- return d;
-}
-
-/*
- - freedfa - free a DFA
- ^ static VOID freedfa(struct dfa *);
- */
-static VOID
-freedfa(d)
-struct dfa *d;
-{
- if (d->cptsmalloced) {
- if (d->ssets != NULL)
- FREE(d->ssets);
- if (d->statesarea != NULL)
- FREE(d->statesarea);
- if (d->outsarea != NULL)
- FREE(d->outsarea);
- if (d->incarea != NULL)
- FREE(d->incarea);
- }
-
- if (d->mallocarea != NULL)
- FREE(d->mallocarea);
-}
-
-/*
- - hash - construct a hash code for a bitvector
- * There are probably better ways, but they're more expensive.
- ^ static unsigned hash(unsigned *, int);
- */
-static unsigned
-hash(uv, n)
-unsigned *uv;
-int n;
-{
- int i;
- unsigned h;
-
- h = 0;
- for (i = 0; i < n; i++)
- h ^= uv[i];
- return h;
-}
-
-/*
- - initialize - hand-craft a cache entry for startup, otherwise get ready
- ^ static struct sset *initialize(struct vars *, struct dfa *, chr *);
- */
-static struct sset *
-initialize(v, d, start)
-struct vars *v; /* used only for debug flags */
-struct dfa *d;
-chr *start;
-{
- struct sset *ss;
- int i;
-
- /* is previous one still there? */
- if (d->nssused > 0 && (d->ssets[0].flags&STARTER))
- ss = &d->ssets[0];
- else { /* no, must (re)build it */
- ss = getvacant(v, d, start, start);
- for (i = 0; i < d->wordsper; i++)
- ss->states[i] = 0;
- BSET(ss->states, d->cnfa->pre);
- ss->hash = HASH(ss->states, d->wordsper);
- assert(d->cnfa->pre != d->cnfa->post);
- ss->flags = STARTER|LOCKED|NOPROGRESS;
- /* lastseen dealt with below */
- }
-
- for (i = 0; i < d->nssused; i++)
- d->ssets[i].lastseen = NULL;
- ss->lastseen = start; /* maybe untrue, but harmless */
- d->lastpost = NULL;
- d->lastnopr = NULL;
- return ss;
-}
-
-/*
- - miss - handle a cache miss
- ^ static struct sset *miss(struct vars *, struct dfa *, struct sset *,
- ^ pcolor, chr *, chr *);
- */
-static struct sset * /* NULL if goes to empty set */
-miss(v, d, css, co, cp, start)
-struct vars *v; /* used only for debug flags */
-struct dfa *d;
-struct sset *css;
-pcolor co;
-chr *cp; /* next chr */
-chr *start; /* where the attempt got started */
-{
- struct cnfa *cnfa = d->cnfa;
- int i;
- unsigned h;
- struct carc *ca;
- struct sset *p;
- int ispost;
- int noprogress;
- int gotstate;
- int dolacons;
- int sawlacons;
-
- /* for convenience, we can be called even if it might not be a miss */
- if (css->outs[co] != NULL) {
- FDEBUG(("hit\n"));
- return css->outs[co];
- }
- FDEBUG(("miss\n"));
-
- /* first, what set of states would we end up in? */
- for (i = 0; i < d->wordsper; i++)
- d->work[i] = 0;
- ispost = 0;
- noprogress = 1;
- gotstate = 0;
- for (i = 0; i < d->nstates; i++)
- if (ISBSET(css->states, i))
- for (ca = cnfa->states[i]+1; ca->co != COLORLESS; ca++)
- if (ca->co == co) {
- BSET(d->work, ca->to);
- gotstate = 1;
- if (ca->to == cnfa->post)
- ispost = 1;
- if (!cnfa->states[ca->to]->co)
- noprogress = 0;
- FDEBUG(("%d -> %d\n", i, ca->to));
- }
- dolacons = (gotstate) ? (cnfa->flags&HASLACONS) : 0;
- sawlacons = 0;
- while (dolacons) { /* transitive closure */
- dolacons = 0;
- for (i = 0; i < d->nstates; i++)
- if (ISBSET(d->work, i))
- for (ca = cnfa->states[i]+1; ca->co != COLORLESS;
- ca++) {
- if (ca->co <= cnfa->ncolors)
- continue; /* NOTE CONTINUE */
- sawlacons = 1;
- if (ISBSET(d->work, ca->to))
- continue; /* NOTE CONTINUE */
- if (!lacon(v, cnfa, cp, ca->co))
- continue; /* NOTE CONTINUE */
- BSET(d->work, ca->to);
- dolacons = 1;
- if (ca->to == cnfa->post)
- ispost = 1;
- if (!cnfa->states[ca->to]->co)
- noprogress = 0;
- FDEBUG(("%d :> %d\n", i, ca->to));
- }
- }
- if (!gotstate)
- return NULL;
- h = HASH(d->work, d->wordsper);
-
- /* next, is that in the cache? */
- for (p = d->ssets, i = d->nssused; i > 0; p++, i--)
- if (HIT(h, d->work, p, d->wordsper)) {
- FDEBUG(("cached c%d\n", p - d->ssets));
- break; /* NOTE BREAK OUT */
- }
- if (i == 0) { /* nope, need a new cache entry */
- p = getvacant(v, d, cp, start);
- assert(p != css);
- for (i = 0; i < d->wordsper; i++)
- p->states[i] = d->work[i];
- p->hash = h;
- p->flags = (ispost) ? POSTSTATE : 0;
- if (noprogress)
- p->flags |= NOPROGRESS;
- /* lastseen to be dealt with by caller */
- }
-
- if (!sawlacons) { /* lookahead conds. always cache miss */
- FDEBUG(("c%d[%d]->%d\n", css - d->ssets, co, p - d->ssets));
- css->outs[co] = p;
- css->inchain[co] = p->ins;
- p->ins.ss = css;
- p->ins.co = (color)co;
- }
- return p;
-}
-
-/*
- - lacon - lookahead-constraint checker for miss()
- ^ static int lacon(struct vars *, struct cnfa *, chr *, pcolor);
- */
-static int /* predicate: constraint satisfied? */
-lacon(v, pcnfa, cp, co)
-struct vars *v;
-struct cnfa *pcnfa; /* parent cnfa */
-chr *cp;
-pcolor co; /* "color" of the lookahead constraint */
-{
- int n;
- struct subre *sub;
- struct dfa *d;
- struct smalldfa sd;
- chr *end;
-
- n = co - pcnfa->ncolors;
- assert(n < v->g->nlacons && v->g->lacons != NULL);
- FDEBUG(("=== testing lacon %d\n", n));
- sub = &v->g->lacons[n];
- d = newdfa(v, &sub->cnfa, &v->g->cmap, &sd);
- if (d == NULL) {
- ERR(REG_ESPACE);
- return 0;
- }
- end = longest(v, d, cp, v->stop, (int *)NULL);
- freedfa(d);
- FDEBUG(("=== lacon %d match %d\n", n, (end != NULL)));
- return (sub->subno) ? (end != NULL) : (end == NULL);
-}
-
-/*
- - getvacant - get a vacant state set
- * This routine clears out the inarcs and outarcs, but does not otherwise
- * clear the innards of the state set -- that's up to the caller.
- ^ static struct sset *getvacant(struct vars *, struct dfa *, chr *, chr *);
- */
-static struct sset *
-getvacant(v, d, cp, start)
-struct vars *v; /* used only for debug flags */
-struct dfa *d;
-chr *cp;
-chr *start;
-{
- int i;
- struct sset *ss;
- struct sset *p;
- struct arcp ap;
- struct arcp lastap;
- color co;
-
- ss = pickss(v, d, cp, start);
- assert(!(ss->flags&LOCKED));
-
- /* clear out its inarcs, including self-referential ones */
- ap = ss->ins;
- while ((p = ap.ss) != NULL) {
- co = ap.co;
- FDEBUG(("zapping c%d's %ld outarc\n", p - d->ssets, (long)co));
- p->outs[co] = NULL;
- ap = p->inchain[co];
- p->inchain[co].ss = NULL; /* paranoia */
- }
- ss->ins.ss = NULL;
-
- /* take it off the inarc chains of the ssets reached by its outarcs */
- for (i = 0; i < d->ncolors; i++) {
- p = ss->outs[i];
- assert(p != ss); /* not self-referential */
- if (p == NULL)
- continue; /* NOTE CONTINUE */
- FDEBUG(("del outarc %d from c%d's in chn\n", i, p - d->ssets));
- if (p->ins.ss == ss && p->ins.co == i)
- p->ins = ss->inchain[i];
- else {
- assert(p->ins.ss != NULL);
- for (ap = p->ins; ap.ss != NULL &&
- !(ap.ss == ss && ap.co == i);
- ap = ap.ss->inchain[ap.co])
- lastap = ap;
- assert(ap.ss != NULL);
- lastap.ss->inchain[lastap.co] = ss->inchain[i];
- }
- ss->outs[i] = NULL;
- ss->inchain[i].ss = NULL;
- }
-
- /* if ss was a success state, may need to remember location */
- if ((ss->flags&POSTSTATE) && ss->lastseen != d->lastpost &&
- (d->lastpost == NULL || d->lastpost < ss->lastseen))
- d->lastpost = ss->lastseen;
-
- /* likewise for a no-progress state */
- if ((ss->flags&NOPROGRESS) && ss->lastseen != d->lastnopr &&
- (d->lastnopr == NULL || d->lastnopr < ss->lastseen))
- d->lastnopr = ss->lastseen;
-
- return ss;
-}
-
-/*
- - pickss - pick the next stateset to be used
- ^ static struct sset *pickss(struct vars *, struct dfa *, chr *, chr *);
- */
-static struct sset *
-pickss(v, d, cp, start)
-struct vars *v; /* used only for debug flags */
-struct dfa *d;
-chr *cp;
-chr *start;
-{
- int i;
- struct sset *ss;
- struct sset *end;
- chr *ancient;
-
- /* shortcut for cases where cache isn't full */
- if (d->nssused < d->nssets) {
- i = d->nssused;
- d->nssused++;
- ss = &d->ssets[i];
- FDEBUG(("new c%d\n", i));
- /* set up innards */
- ss->states = &d->statesarea[i * d->wordsper];
- ss->flags = 0;
- ss->ins.ss = NULL;
- ss->ins.co = WHITE; /* give it some value */
- ss->outs = &d->outsarea[i * d->ncolors];
- ss->inchain = &d->incarea[i * d->ncolors];
- for (i = 0; i < d->ncolors; i++) {
- ss->outs[i] = NULL;
- ss->inchain[i].ss = NULL;
- }
- return ss;
- }
-
- /* look for oldest, or old enough anyway */
- if (cp - start > d->nssets*2/3) /* oldest 33% are expendable */
- ancient = cp - d->nssets*2/3;
- else
- ancient = start;
- for (ss = d->search, end = &d->ssets[d->nssets]; ss < end; ss++)
- if ((ss->lastseen == NULL || ss->lastseen < ancient) &&
- !(ss->flags&LOCKED)) {
- d->search = ss + 1;
- FDEBUG(("replacing c%d\n", ss - d->ssets));
- return ss;
- }
- for (ss = d->ssets, end = d->search; ss < end; ss++)
- if ((ss->lastseen == NULL || ss->lastseen < ancient) &&
- !(ss->flags&LOCKED)) {
- d->search = ss + 1;
- FDEBUG(("replacing c%d\n", ss - d->ssets));
- return ss;
- }
-
- /* nobody's old enough?!? -- something's really wrong */
- FDEBUG(("can't find victim to replace!\n"));
- assert(NOTREACHED);
- ERR(REG_ASSERT);
- return d->ssets;
-}
+/* + * DFA routines + * This file is #included by regexec.c. + * + * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved. + * + * Development of this software was funded, in part, by Cray Research Inc., + * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics + * Corporation, none of whom are responsible for the results. The author + * thanks all of them. + * + * Redistribution and use in source and binary forms -- with or without + * modification -- are permitted for any purpose, provided that + * redistributions in source form retain this entire copyright notice and + * indicate the origin and nature of any modifications. + * + * I'd appreciate being given credit for this package in the documentation + * of software which uses it, but that is not a requirement. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +/* + - longest - longest-preferred matching engine + ^ static chr *longest(struct vars *, struct dfa *, chr *, chr *, int *); + */ +static chr * /* endpoint, or NULL */ +longest(v, d, start, stop, hitstopp) +struct vars *v; /* used only for debug and exec flags */ +struct dfa *d; +chr *start; /* where the match should start */ +chr *stop; /* match must end at or before here */ +int *hitstopp; /* record whether hit v->stop, if non-NULL */ +{ + chr *cp; + chr *realstop = (stop == v->stop) ? stop : stop + 1; + color co; + struct sset *css; + struct sset *ss; + chr *post; + int i; + struct colormap *cm = d->cm; + + /* initialize */ + css = initialize(v, d, start); + cp = start; + if (hitstopp != NULL) + *hitstopp = 0; + + /* startup */ + FDEBUG(("+++ startup +++\n")); + if (cp == v->start) { + co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1]; + FDEBUG(("color %ld\n", (long)co)); + } else { + co = GETCOLOR(cm, *(cp - 1)); + FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co)); + } + css = miss(v, d, css, co, cp, start); + if (css == NULL) + return NULL; + css->lastseen = cp; + + /* main loop */ + if (v->eflags®_FTRACE) + while (cp < realstop) { + FDEBUG(("+++ at c%d +++\n", css - d->ssets)); + co = GETCOLOR(cm, *cp); + FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co)); + ss = css->outs[co]; + if (ss == NULL) { + ss = miss(v, d, css, co, cp+1, start); + if (ss == NULL) + break; /* NOTE BREAK OUT */ + } + cp++; + ss->lastseen = cp; + css = ss; + } + else + while (cp < realstop) { + co = GETCOLOR(cm, *cp); + ss = css->outs[co]; + if (ss == NULL) { + ss = miss(v, d, css, co, cp+1, start); + if (ss == NULL) + break; /* NOTE BREAK OUT */ + } + cp++; + ss->lastseen = cp; + css = ss; + } + + /* shutdown */ + FDEBUG(("+++ shutdown at c%d +++\n", css - d->ssets)); + if (cp == v->stop && stop == v->stop) { + if (hitstopp != NULL) + *hitstopp = 1; + co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1]; + FDEBUG(("color %ld\n", (long)co)); + ss = miss(v, d, css, co, cp, start); + /* special case: match ended at eol? */ + if (ss != NULL && (ss->flags&POSTSTATE)) + return cp; + else if (ss != NULL) + ss->lastseen = cp; /* to be tidy */ + } + + /* find last match, if any */ + post = d->lastpost; + for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--) + if ((ss->flags&POSTSTATE) && post != ss->lastseen && + (post == NULL || post < ss->lastseen)) + post = ss->lastseen; + if (post != NULL) /* found one */ + return post - 1; + + return NULL; +} + +/* + - shortest - shortest-preferred matching engine + ^ static chr *shortest(struct vars *, struct dfa *, chr *, chr *, chr *, + ^ chr **, int *); + */ +static chr * /* endpoint, or NULL */ +shortest(v, d, start, min, max, coldp, hitstopp) +struct vars *v; +struct dfa *d; +chr *start; /* where the match should start */ +chr *min; /* match must end at or after here */ +chr *max; /* match must end at or before here */ +chr **coldp; /* store coldstart pointer here, if nonNULL */ +int *hitstopp; /* record whether hit v->stop, if non-NULL */ +{ + chr *cp; + chr *realmin = (min == v->stop) ? min : min + 1; + chr *realmax = (max == v->stop) ? max : max + 1; + color co; + struct sset *css; + struct sset *ss; + struct colormap *cm = d->cm; + + /* initialize */ + css = initialize(v, d, start); + cp = start; + if (hitstopp != NULL) + *hitstopp = 0; + + /* startup */ + FDEBUG(("--- startup ---\n")); + if (cp == v->start) { + co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1]; + FDEBUG(("color %ld\n", (long)co)); + } else { + co = GETCOLOR(cm, *(cp - 1)); + FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co)); + } + css = miss(v, d, css, co, cp, start); + if (css == NULL) + return NULL; + css->lastseen = cp; + ss = css; + + /* main loop */ + if (v->eflags®_FTRACE) + while (cp < realmax) { + FDEBUG(("--- at c%d ---\n", css - d->ssets)); + co = GETCOLOR(cm, *cp); + FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co)); + ss = css->outs[co]; + if (ss == NULL) { + ss = miss(v, d, css, co, cp+1, start); + if (ss == NULL) + break; /* NOTE BREAK OUT */ + } + cp++; + ss->lastseen = cp; + css = ss; + if ((ss->flags&POSTSTATE) && cp >= realmin) + break; /* NOTE BREAK OUT */ + } + else + while (cp < realmax) { + co = GETCOLOR(cm, *cp); + ss = css->outs[co]; + if (ss == NULL) { + ss = miss(v, d, css, co, cp+1, start); + if (ss == NULL) + break; /* NOTE BREAK OUT */ + } + cp++; + ss->lastseen = cp; + css = ss; + if ((ss->flags&POSTSTATE) && cp >= realmin) + break; /* NOTE BREAK OUT */ + } + + if (ss == NULL) + return NULL; + + if (coldp != NULL) /* report last no-progress state set, if any */ + *coldp = lastcold(v, d); + + if ((ss->flags&POSTSTATE) && cp > min) { + assert(cp >= realmin); + cp--; + } else if (cp == v->stop && max == v->stop) { + co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1]; + FDEBUG(("color %ld\n", (long)co)); + ss = miss(v, d, css, co, cp, start); + /* match might have ended at eol */ + if ((ss == NULL || !(ss->flags&POSTSTATE)) && hitstopp != NULL) + *hitstopp = 1; + } + + if (ss == NULL || !(ss->flags&POSTSTATE)) + return NULL; + + return cp; +} + +/* + - lastcold - determine last point at which no progress had been made + ^ static chr *lastcold(struct vars *, struct dfa *); + */ +static chr * /* endpoint, or NULL */ +lastcold(v, d) +struct vars *v; +struct dfa *d; +{ + struct sset *ss; + chr *nopr; + int i; + + nopr = d->lastnopr; + if (nopr == NULL) + nopr = v->start; + for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--) + if ((ss->flags&NOPROGRESS) && nopr < ss->lastseen) + nopr = ss->lastseen; + return nopr; +} + +/* + - newdfa - set up a fresh DFA + ^ static struct dfa *newdfa(struct vars *, struct cnfa *, + ^ struct colormap *, struct smalldfa *); + */ +static struct dfa * +newdfa(v, cnfa, cm, small) +struct vars *v; +struct cnfa *cnfa; +struct colormap *cm; +struct smalldfa *small; /* preallocated space, may be NULL */ +{ + struct dfa *d; + size_t nss = cnfa->nstates * 2; + int wordsper = (cnfa->nstates + UBITS - 1) / UBITS; + struct smalldfa *smallwas = small; + + assert(cnfa != NULL && cnfa->nstates != 0); + + if (nss <= FEWSTATES && cnfa->ncolors <= FEWCOLORS) { + assert(wordsper == 1); + if (small == NULL) { + small = (struct smalldfa *)MALLOC( + sizeof(struct smalldfa)); + if (small == NULL) { + ERR(REG_ESPACE); + return NULL; + } + } + d = &small->dfa; + d->ssets = small->ssets; + d->statesarea = small->statesarea; + d->work = &d->statesarea[nss]; + d->outsarea = small->outsarea; + d->incarea = small->incarea; + d->cptsmalloced = 0; + d->mallocarea = (smallwas == NULL) ? (char *)small : NULL; + } else { + d = (struct dfa *)MALLOC(sizeof(struct dfa)); + if (d == NULL) { + ERR(REG_ESPACE); + return NULL; + } + d->ssets = (struct sset *)MALLOC(nss * sizeof(struct sset)); + d->statesarea = (unsigned *)MALLOC((nss+WORK) * wordsper * + sizeof(unsigned)); + d->work = &d->statesarea[nss * wordsper]; + d->outsarea = (struct sset **)MALLOC(nss * cnfa->ncolors * + sizeof(struct sset *)); + d->incarea = (struct arcp *)MALLOC(nss * cnfa->ncolors * + sizeof(struct arcp)); + d->cptsmalloced = 1; + d->mallocarea = (char *)d; + if (d->ssets == NULL || d->statesarea == NULL || + d->outsarea == NULL || d->incarea == NULL) { + freedfa(d); + ERR(REG_ESPACE); + return NULL; + } + } + + d->nssets = (v->eflags®_SMALL) ? 7 : nss; + d->nssused = 0; + d->nstates = cnfa->nstates; + d->ncolors = cnfa->ncolors; + d->wordsper = wordsper; + d->cnfa = cnfa; + d->cm = cm; + d->lastpost = NULL; + d->lastnopr = NULL; + d->search = d->ssets; + + /* initialization of sset fields is done as needed */ + + return d; +} + +/* + - freedfa - free a DFA + ^ static VOID freedfa(struct dfa *); + */ +static VOID +freedfa(d) +struct dfa *d; +{ + if (d->cptsmalloced) { + if (d->ssets != NULL) + FREE(d->ssets); + if (d->statesarea != NULL) + FREE(d->statesarea); + if (d->outsarea != NULL) + FREE(d->outsarea); + if (d->incarea != NULL) + FREE(d->incarea); + } + + if (d->mallocarea != NULL) + FREE(d->mallocarea); +} + +/* + - hash - construct a hash code for a bitvector + * There are probably better ways, but they're more expensive. + ^ static unsigned hash(unsigned *, int); + */ +static unsigned +hash(uv, n) +unsigned *uv; +int n; +{ + int i; + unsigned h; + + h = 0; + for (i = 0; i < n; i++) + h ^= uv[i]; + return h; +} + +/* + - initialize - hand-craft a cache entry for startup, otherwise get ready + ^ static struct sset *initialize(struct vars *, struct dfa *, chr *); + */ +static struct sset * +initialize(v, d, start) +struct vars *v; /* used only for debug flags */ +struct dfa *d; +chr *start; +{ + struct sset *ss; + int i; + + /* is previous one still there? */ + if (d->nssused > 0 && (d->ssets[0].flags&STARTER)) + ss = &d->ssets[0]; + else { /* no, must (re)build it */ + ss = getvacant(v, d, start, start); + for (i = 0; i < d->wordsper; i++) + ss->states[i] = 0; + BSET(ss->states, d->cnfa->pre); + ss->hash = HASH(ss->states, d->wordsper); + assert(d->cnfa->pre != d->cnfa->post); + ss->flags = STARTER|LOCKED|NOPROGRESS; + /* lastseen dealt with below */ + } + + for (i = 0; i < d->nssused; i++) + d->ssets[i].lastseen = NULL; + ss->lastseen = start; /* maybe untrue, but harmless */ + d->lastpost = NULL; + d->lastnopr = NULL; + return ss; +} + +/* + - miss - handle a cache miss + ^ static struct sset *miss(struct vars *, struct dfa *, struct sset *, + ^ pcolor, chr *, chr *); + */ +static struct sset * /* NULL if goes to empty set */ +miss(v, d, css, co, cp, start) +struct vars *v; /* used only for debug flags */ +struct dfa *d; +struct sset *css; +pcolor co; +chr *cp; /* next chr */ +chr *start; /* where the attempt got started */ +{ + struct cnfa *cnfa = d->cnfa; + int i; + unsigned h; + struct carc *ca; + struct sset *p; + int ispost; + int noprogress; + int gotstate; + int dolacons; + int sawlacons; + + /* for convenience, we can be called even if it might not be a miss */ + if (css->outs[co] != NULL) { + FDEBUG(("hit\n")); + return css->outs[co]; + } + FDEBUG(("miss\n")); + + /* first, what set of states would we end up in? */ + for (i = 0; i < d->wordsper; i++) + d->work[i] = 0; + ispost = 0; + noprogress = 1; + gotstate = 0; + for (i = 0; i < d->nstates; i++) + if (ISBSET(css->states, i)) + for (ca = cnfa->states[i]+1; ca->co != COLORLESS; ca++) + if (ca->co == co) { + BSET(d->work, ca->to); + gotstate = 1; + if (ca->to == cnfa->post) + ispost = 1; + if (!cnfa->states[ca->to]->co) + noprogress = 0; + FDEBUG(("%d -> %d\n", i, ca->to)); + } + dolacons = (gotstate) ? (cnfa->flags&HASLACONS) : 0; + sawlacons = 0; + while (dolacons) { /* transitive closure */ + dolacons = 0; + for (i = 0; i < d->nstates; i++) + if (ISBSET(d->work, i)) + for (ca = cnfa->states[i]+1; ca->co != COLORLESS; + ca++) { + if (ca->co <= cnfa->ncolors) + continue; /* NOTE CONTINUE */ + sawlacons = 1; + if (ISBSET(d->work, ca->to)) + continue; /* NOTE CONTINUE */ + if (!lacon(v, cnfa, cp, ca->co)) + continue; /* NOTE CONTINUE */ + BSET(d->work, ca->to); + dolacons = 1; + if (ca->to == cnfa->post) + ispost = 1; + if (!cnfa->states[ca->to]->co) + noprogress = 0; + FDEBUG(("%d :> %d\n", i, ca->to)); + } + } + if (!gotstate) + return NULL; + h = HASH(d->work, d->wordsper); + + /* next, is that in the cache? */ + for (p = d->ssets, i = d->nssused; i > 0; p++, i--) + if (HIT(h, d->work, p, d->wordsper)) { + FDEBUG(("cached c%d\n", p - d->ssets)); + break; /* NOTE BREAK OUT */ + } + if (i == 0) { /* nope, need a new cache entry */ + p = getvacant(v, d, cp, start); + assert(p != css); + for (i = 0; i < d->wordsper; i++) + p->states[i] = d->work[i]; + p->hash = h; + p->flags = (ispost) ? POSTSTATE : 0; + if (noprogress) + p->flags |= NOPROGRESS; + /* lastseen to be dealt with by caller */ + } + + if (!sawlacons) { /* lookahead conds. always cache miss */ + FDEBUG(("c%d[%d]->%d\n", css - d->ssets, co, p - d->ssets)); + css->outs[co] = p; + css->inchain[co] = p->ins; + p->ins.ss = css; + p->ins.co = (color)co; + } + return p; +} + +/* + - lacon - lookahead-constraint checker for miss() + ^ static int lacon(struct vars *, struct cnfa *, chr *, pcolor); + */ +static int /* predicate: constraint satisfied? */ +lacon(v, pcnfa, cp, co) +struct vars *v; +struct cnfa *pcnfa; /* parent cnfa */ +chr *cp; +pcolor co; /* "color" of the lookahead constraint */ +{ + int n; + struct subre *sub; + struct dfa *d; + struct smalldfa sd; + chr *end; + + n = co - pcnfa->ncolors; + assert(n < v->g->nlacons && v->g->lacons != NULL); + FDEBUG(("=== testing lacon %d\n", n)); + sub = &v->g->lacons[n]; + d = newdfa(v, &sub->cnfa, &v->g->cmap, &sd); + if (d == NULL) { + ERR(REG_ESPACE); + return 0; + } + end = longest(v, d, cp, v->stop, (int *)NULL); + freedfa(d); + FDEBUG(("=== lacon %d match %d\n", n, (end != NULL))); + return (sub->subno) ? (end != NULL) : (end == NULL); +} + +/* + - getvacant - get a vacant state set + * This routine clears out the inarcs and outarcs, but does not otherwise + * clear the innards of the state set -- that's up to the caller. + ^ static struct sset *getvacant(struct vars *, struct dfa *, chr *, chr *); + */ +static struct sset * +getvacant(v, d, cp, start) +struct vars *v; /* used only for debug flags */ +struct dfa *d; +chr *cp; +chr *start; +{ + int i; + struct sset *ss; + struct sset *p; + struct arcp ap; + struct arcp lastap; + color co; + + ss = pickss(v, d, cp, start); + assert(!(ss->flags&LOCKED)); + + /* clear out its inarcs, including self-referential ones */ + ap = ss->ins; + while ((p = ap.ss) != NULL) { + co = ap.co; + FDEBUG(("zapping c%d's %ld outarc\n", p - d->ssets, (long)co)); + p->outs[co] = NULL; + ap = p->inchain[co]; + p->inchain[co].ss = NULL; /* paranoia */ + } + ss->ins.ss = NULL; + + /* take it off the inarc chains of the ssets reached by its outarcs */ + for (i = 0; i < d->ncolors; i++) { + p = ss->outs[i]; + assert(p != ss); /* not self-referential */ + if (p == NULL) + continue; /* NOTE CONTINUE */ + FDEBUG(("del outarc %d from c%d's in chn\n", i, p - d->ssets)); + if (p->ins.ss == ss && p->ins.co == i) + p->ins = ss->inchain[i]; + else { + assert(p->ins.ss != NULL); + for (ap = p->ins; ap.ss != NULL && + !(ap.ss == ss && ap.co == i); + ap = ap.ss->inchain[ap.co]) + lastap = ap; + assert(ap.ss != NULL); + lastap.ss->inchain[lastap.co] = ss->inchain[i]; + } + ss->outs[i] = NULL; + ss->inchain[i].ss = NULL; + } + + /* if ss was a success state, may need to remember location */ + if ((ss->flags&POSTSTATE) && ss->lastseen != d->lastpost && + (d->lastpost == NULL || d->lastpost < ss->lastseen)) + d->lastpost = ss->lastseen; + + /* likewise for a no-progress state */ + if ((ss->flags&NOPROGRESS) && ss->lastseen != d->lastnopr && + (d->lastnopr == NULL || d->lastnopr < ss->lastseen)) + d->lastnopr = ss->lastseen; + + return ss; +} + +/* + - pickss - pick the next stateset to be used + ^ static struct sset *pickss(struct vars *, struct dfa *, chr *, chr *); + */ +static struct sset * +pickss(v, d, cp, start) +struct vars *v; /* used only for debug flags */ +struct dfa *d; +chr *cp; +chr *start; +{ + int i; + struct sset *ss; + struct sset *end; + chr *ancient; + + /* shortcut for cases where cache isn't full */ + if (d->nssused < d->nssets) { + i = d->nssused; + d->nssused++; + ss = &d->ssets[i]; + FDEBUG(("new c%d\n", i)); + /* set up innards */ + ss->states = &d->statesarea[i * d->wordsper]; + ss->flags = 0; + ss->ins.ss = NULL; + ss->ins.co = WHITE; /* give it some value */ + ss->outs = &d->outsarea[i * d->ncolors]; + ss->inchain = &d->incarea[i * d->ncolors]; + for (i = 0; i < d->ncolors; i++) { + ss->outs[i] = NULL; + ss->inchain[i].ss = NULL; + } + return ss; + } + + /* look for oldest, or old enough anyway */ + if (cp - start > d->nssets*2/3) /* oldest 33% are expendable */ + ancient = cp - d->nssets*2/3; + else + ancient = start; + for (ss = d->search, end = &d->ssets[d->nssets]; ss < end; ss++) + if ((ss->lastseen == NULL || ss->lastseen < ancient) && + !(ss->flags&LOCKED)) { + d->search = ss + 1; + FDEBUG(("replacing c%d\n", ss - d->ssets)); + return ss; + } + for (ss = d->ssets, end = d->search; ss < end; ss++) + if ((ss->lastseen == NULL || ss->lastseen < ancient) && + !(ss->flags&LOCKED)) { + d->search = ss + 1; + FDEBUG(("replacing c%d\n", ss - d->ssets)); + return ss; + } + + /* nobody's old enough?!? -- something's really wrong */ + FDEBUG(("can't find victim to replace!\n")); + assert(NOTREACHED); + ERR(REG_ASSERT); + return d->ssets; +} |