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authorWilliam Joye <wjoye@cfa.harvard.edu>2017-09-22 18:51:12 (GMT)
committerWilliam Joye <wjoye@cfa.harvard.edu>2017-09-22 18:51:12 (GMT)
commit3fa8e6dc88e8041b6cb88d1b1e9c05676d3346b7 (patch)
tree69afbb41089c8358615879f7cd3c4cf7997f4c7e /tcl8.6/generic/regc_nfa.c
parenta0e17db23c0fd7c771c0afce8cce350c98f90b02 (diff)
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update to tcl/tk 8.6.7
Diffstat (limited to 'tcl8.6/generic/regc_nfa.c')
-rw-r--r--tcl8.6/generic/regc_nfa.c3213
1 files changed, 0 insertions, 3213 deletions
diff --git a/tcl8.6/generic/regc_nfa.c b/tcl8.6/generic/regc_nfa.c
deleted file mode 100644
index 088c6c0..0000000
--- a/tcl8.6/generic/regc_nfa.c
+++ /dev/null
@@ -1,3213 +0,0 @@
-/*
- * NFA utilities.
- * This file is #included by regcomp.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.
- *
- * One or two things that technically ought to be in here are actually in
- * color.c, thanks to some incestuous relationships in the color chains.
- */
-
-#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
- ^ static struct nfa *newnfa(struct vars *, struct colormap *, struct nfa *);
- */
-static struct nfa * /* the NFA, or NULL */
-newnfa(
- struct vars *v,
- struct colormap *cm,
- struct nfa *parent) /* NULL if primary NFA */
-{
- struct nfa *nfa;
-
- nfa = (struct nfa *) MALLOC(sizeof(struct nfa));
- if (nfa == NULL) {
- ERR(REG_ESPACE);
- return NULL;
- }
-
- nfa->states = NULL;
- nfa->slast = NULL;
- nfa->free = NULL;
- nfa->nstates = 0;
- nfa->cm = cm;
- nfa->v = v;
- nfa->bos[0] = nfa->bos[1] = COLORLESS;
- nfa->eos[0] = nfa->eos[1] = COLORLESS;
- nfa->parent = parent; /* Precedes newfstate so parent is valid. */
- nfa->post = newfstate(nfa, '@'); /* number 0 */
- nfa->pre = newfstate(nfa, '>'); /* number 1 */
-
- nfa->init = newstate(nfa); /* May become invalid later. */
- nfa->final = newstate(nfa);
- if (ISERR()) {
- freenfa(nfa);
- return NULL;
- }
- rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init);
- newarc(nfa, '^', 1, nfa->pre, nfa->init);
- newarc(nfa, '^', 0, nfa->pre, nfa->init);
- rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post);
- newarc(nfa, '$', 1, nfa->final, nfa->post);
- newarc(nfa, '$', 0, nfa->final, nfa->post);
-
- if (ISERR()) {
- freenfa(nfa);
- return NULL;
- }
- return nfa;
-}
-
-/*
- - freenfa - free an entire NFA
- ^ static void freenfa(struct nfa *);
- */
-static void
-freenfa(
- struct nfa *nfa)
-{
- struct state *s;
-
- while ((s = nfa->states) != NULL) {
- s->nins = s->nouts = 0; /* don't worry about arcs */
- freestate(nfa, s);
- }
- while ((s = nfa->free) != NULL) {
- nfa->free = s->next;
- destroystate(nfa, s);
- }
-
- nfa->slast = NULL;
- nfa->nstates = -1;
- nfa->pre = NULL;
- nfa->post = NULL;
- FREE(nfa);
-}
-
-/*
- - newstate - allocate an NFA state, with zero flag value
- ^ static struct state *newstate(struct nfa *);
- */
-static struct state * /* NULL on error */
-newstate(
- struct nfa *nfa)
-{
- struct state *s;
-
- 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;
- }
-
- assert(nfa->nstates >= 0);
- s->no = nfa->nstates++;
- s->flag = 0;
- if (nfa->states == NULL) {
- nfa->states = s;
- }
- s->nins = 0;
- s->ins = NULL;
- s->nouts = 0;
- s->outs = NULL;
- s->tmp = NULL;
- s->next = NULL;
- if (nfa->slast != NULL) {
- assert(nfa->slast->next == NULL);
- nfa->slast->next = s;
- }
- s->prev = nfa->slast;
- nfa->slast = s;
- return s;
-}
-
-/*
- - newfstate - allocate an NFA state with a specified flag value
- ^ static struct state *newfstate(struct nfa *, int flag);
- */
-static struct state * /* NULL on error */
-newfstate(
- struct nfa *nfa,
- int flag)
-{
- struct state *s;
-
- s = newstate(nfa);
- if (s != NULL) {
- s->flag = (char) flag;
- }
- return s;
-}
-
-/*
- - dropstate - delete a state's inarcs and outarcs and free it
- ^ static void dropstate(struct nfa *, struct state *);
- */
-static void
-dropstate(
- struct nfa *nfa,
- struct state *s)
-{
- struct arc *a;
-
- while ((a = s->ins) != NULL) {
- freearc(nfa, a);
- }
- while ((a = s->outs) != NULL) {
- freearc(nfa, a);
- }
- freestate(nfa, s);
-}
-
-/*
- - freestate - free a state, which has no in-arcs or out-arcs
- ^ static void freestate(struct nfa *, struct state *);
- */
-static void
-freestate(
- struct nfa *nfa,
- struct state *s)
-{
- assert(s != NULL);
- assert(s->nins == 0 && s->nouts == 0);
-
- s->no = FREESTATE;
- s->flag = 0;
- if (s->next != NULL) {
- s->next->prev = s->prev;
- } else {
- assert(s == nfa->slast);
- nfa->slast = s->prev;
- }
- if (s->prev != NULL) {
- s->prev->next = s->next;
- } else {
- assert(s == nfa->states);
- nfa->states = s->next;
- }
- s->prev = NULL;
- s->next = nfa->free; /* don't delete it, put it on the free list */
- nfa->free = s;
-}
-
-/*
- - destroystate - really get rid of an already-freed state
- ^ static void destroystate(struct nfa *, struct state *);
- */
-static void
-destroystate(
- struct nfa *nfa,
- struct state *s)
-{
- struct arcbatch *ab;
- struct arcbatch *abnext;
-
- assert(s->no == FREESTATE);
- for (ab=s->oas.next ; ab!=NULL ; ab=abnext) {
- abnext = ab->next;
- FREE(ab);
- nfa->v->spaceused -= sizeof(struct arcbatch);
- }
- s->ins = NULL;
- s->outs = NULL;
- s->next = NULL;
- FREE(s);
- nfa->v->spaceused -= sizeof(struct state);
-}
-
-/*
- - newarc - set up a new arc within an NFA
- ^ 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,
- int t,
- pcolor co,
- struct state *from,
- struct state *to)
-{
- struct arc *a;
-
- assert(from != NULL && to != NULL);
-
- /* 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;
- }
- assert(a != NULL);
-
- a->type = t;
- a->co = (color) co;
- a->to = to;
- a->from = from;
-
- /*
- * Put the new arc on the beginning, not the end, of the chains; 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++;
- to->nins++;
-
- if (COLORED(a) && nfa->parent == NULL) {
- colorchain(nfa->cm, a);
- }
-}
-
-/*
- - allocarc - allocate a new out-arc within a state
- ^ static struct arc *allocarc(struct nfa *, struct state *);
- */
-static struct arc * /* NULL for failure */
-allocarc(
- struct nfa *nfa,
- struct state *s)
-{
- struct arc *a;
-
- /*
- * Shortcut
- */
-
- if (s->free == NULL && s->noas < ABSIZE) {
- a = &s->oas.a[s->noas];
- s->noas++;
- return a;
- }
-
- /*
- * if none at hand, get more
- */
-
- if (s->free == NULL) {
- struct arcbatch *newAb;
- int i;
-
- 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;
-
- for (i=0 ; i<ABSIZE ; i++) {
- newAb->a[i].type = 0;
- newAb->a[i].freechain = &newAb->a[i+1];
- }
- newAb->a[ABSIZE-1].freechain = NULL;
- s->free = &newAb->a[0];
- }
- assert(s->free != NULL);
-
- a = s->free;
- s->free = a->freechain;
- return a;
-}
-
-/*
- - freearc - free an arc
- ^ static void freearc(struct nfa *, struct arc *);
- */
-static void
-freearc(
- struct nfa *nfa,
- struct arc *victim)
-{
- struct state *from = victim->from;
- struct state *to = victim->to;
- struct arc *predecessor;
-
- assert(victim->type != 0);
-
- /*
- * Take it off color chain if necessary.
- */
-
- if (COLORED(victim) && nfa->parent == NULL) {
- uncolorchain(nfa->cm, victim);
- }
-
- /*
- * Take it off source's out-chain.
- */
-
- assert(from != NULL);
- predecessor = victim->outchainRev;
- if (predecessor == NULL) {
- assert(from->outs == victim);
- from->outs = victim->outchain;
- } else {
- assert(predecessor->outchain == victim);
- predecessor->outchain = victim->outchain;
- }
- if (victim->outchain != NULL) {
- assert(victim->outchain->outchainRev == victim);
- victim->outchain->outchainRev = predecessor;
- }
- from->nouts--;
-
- /*
- * Take it off target's in-chain.
- */
-
- assert(to != NULL);
- predecessor = victim->inchainRev;
- if (predecessor == NULL) {
- assert(to->ins == victim);
- to->ins = victim->inchain;
- } else {
- 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 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;
-}
-
-/*
- * 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 void
-changearctarget(struct arc * a, struct state * newto)
-{
- struct state *oldto = a->to;
- struct arc *predecessor;
-
- 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;
- }
- if (a->inchain != NULL) {
- assert(a->inchain->inchainRev == a);
- a->inchain->inchainRev = predecessor;
- }
- oldto->nins--;
-
- 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;
- }
- newto->ins = a;
- newto->nins++;
-}
-
-/*
- - hasnonemptyout - Does state have a non-EMPTY out arc?
- ^ static int hasnonemptyout(struct state *);
- */
-static int
-hasnonemptyout(
- struct state *s)
-{
- struct arc *a;
-
- for (a = s->outs; a != NULL; a = a->outchain) {
- if (a->type != EMPTY) {
- return 1;
- }
- }
- return 0;
-}
-
-/*
- - findarc - find arc, if any, from given source with given type and color
- * If there is more than one such arc, the result is random.
- ^ static struct arc *findarc(struct state *, int, pcolor);
- */
-static struct arc *
-findarc(
- struct state *s,
- int type,
- pcolor co)
-{
- struct arc *a;
-
- for (a=s->outs ; a!=NULL ; a=a->outchain) {
- if (a->type == type && a->co == co) {
- return a;
- }
- }
- return NULL;
-}
-
-/*
- - cparc - allocate a new arc within an NFA, copying details from old one
- ^ static void cparc(struct nfa *, struct arc *, struct state *,
- ^ struct state *);
- */
-static void
-cparc(
- struct nfa *nfa,
- struct arc *oa,
- struct state *from,
- struct state *to)
-{
- 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 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
-moveins(
- struct nfa *nfa,
- struct state *oldState,
- struct state *newState)
-{
- assert(oldState != newState);
-
- 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
- ^ static VOID copyins(struct nfa *, struct state *, struct state *, int);
- */
-static void
-copyins(
- struct nfa *nfa,
- struct state *oldState,
- struct state *newState)
-{
- assert(oldState != newState);
-
- 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++;
- }
-}
-
-/*
- - moveouts - move all out arcs of a state to another state
- ^ static void moveouts(struct nfa *, struct state *, struct state *);
- */
-static void
-moveouts(
- struct nfa *nfa,
- struct state *oldState,
- struct state *newState)
-{
- assert(oldState != newState);
-
- 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
- ^ static VOID copyouts(struct nfa *, struct state *, struct state *, int);
- */
-static void
-copyouts(
- struct nfa *nfa,
- struct state *oldState,
- struct state *newState)
-{
- assert(oldState != newState);
-
- 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);
- }
- }
-}
-
-/*
- - cloneouts - copy out arcs of a state to another state pair, modifying type
- ^ static void cloneouts(struct nfa *, struct state *, struct state *,
- ^ struct state *, int);
- */
-static void
-cloneouts(
- struct nfa *nfa,
- struct state *old,
- struct state *from,
- struct state *to,
- int type)
-{
- struct arc *a;
-
- assert(old != from);
-
- for (a=old->outs ; a!=NULL ; a=a->outchain) {
- newarc(nfa, type, a->co, from, to);
- }
-}
-
-/*
- - delsub - delete a sub-NFA, updating subre pointers if necessary
- * This uses a recursive traversal of the sub-NFA, marking already-seen
- * states using their tmp pointer.
- ^ static void delsub(struct nfa *, struct state *, struct state *);
- */
-static void
-delsub(
- struct nfa *nfa,
- struct state *lp, /* the sub-NFA goes from here... */
- struct state *rp) /* ...to here, *not* inclusive */
-{
- assert(lp != rp);
-
- rp->tmp = rp; /* mark end */
-
- deltraverse(nfa, lp, lp);
- assert(lp->nouts == 0 && rp->nins == 0); /* did the job */
- assert(lp->no != FREESTATE && rp->no != FREESTATE); /* no more */
-
- rp->tmp = NULL; /* unmark end */
- lp->tmp = NULL; /* and begin, marked by deltraverse */
-}
-
-/*
- - deltraverse - the recursive heart of delsub
- * This routine's basic job is to destroy all out-arcs of the state.
- ^ static void deltraverse(struct nfa *, struct state *, struct state *);
- */
-static void
-deltraverse(
- struct nfa *nfa,
- struct state *leftend,
- struct state *s)
-{
- struct arc *a;
- struct state *to;
-
- if (s->nouts == 0) {
- return; /* nothing to do */
- }
- if (s->tmp != NULL) {
- return; /* already in progress */
- }
-
- s->tmp = s; /* mark as in progress */
-
- while ((a = s->outs) != NULL) {
- to = a->to;
- deltraverse(nfa, leftend, to);
- assert(to->nouts == 0 || to->tmp != NULL);
- freearc(nfa, a);
- if (to->nins == 0 && to->tmp == NULL) {
- assert(to->nouts == 0);
- freestate(nfa, to);
- }
- }
-
- assert(s->no != FREESTATE); /* we're still here */
- assert(s == leftend || s->nins != 0); /* and still reachable */
- assert(s->nouts == 0); /* but have no outarcs */
-
- s->tmp = NULL; /* we're done here */
-}
-
-/*
- - dupnfa - duplicate sub-NFA
- * Another recursive traversal, this time using tmp to point to duplicates as
- * well as mark already-seen states. (You knew there was a reason why it's a
- * state pointer, didn't you? :-))
- ^ static void dupnfa(struct nfa *, struct state *, struct state *,
- ^ struct state *, struct state *);
- */
-static void
-dupnfa(
- struct nfa *nfa,
- struct state *start, /* duplicate of subNFA starting here */
- struct state *stop, /* and stopping here */
- struct state *from, /* stringing duplicate from here */
- struct state *to) /* to here */
-{
- if (start == stop) {
- newarc(nfa, EMPTY, 0, from, to);
- return;
- }
-
- stop->tmp = to;
- duptraverse(nfa, start, from, 0);
- /* done, except for clearing out the tmp pointers */
-
- stop->tmp = NULL;
- cleartraverse(nfa, start);
-}
-
-/*
- - duptraverse - recursive heart of dupnfa
- ^ static void duptraverse(struct nfa *, struct state *, struct state *);
- */
-static void
-duptraverse(
- struct nfa *nfa,
- struct state *s,
- struct state *stmp, /* s's duplicate, or NULL */
- int depth)
-{
- struct arc *a;
-
- if (s->tmp != NULL) {
- return; /* already done */
- }
-
- s->tmp = (stmp == NULL) ? newstate(nfa) : stmp;
- if (s->tmp == NULL) {
- assert(NISERR());
- return;
- }
-
- /*
- * Arbitrary depth limit. Needs tuning, but this value is sufficient to
- * make all normal tests (not reg-33.14) pass.
- */
-#ifndef DUPTRAVERSE_MAX_DEPTH
-#define DUPTRAVERSE_MAX_DEPTH 15000
-#endif
-
- if (depth++ > DUPTRAVERSE_MAX_DEPTH) {
- NERR(REG_ESPACE);
- }
-
- for (a=s->outs ; a!=NULL && !NISERR() ; a=a->outchain) {
- duptraverse(nfa, a->to, NULL, depth);
- if (NISERR()) {
- break;
- }
- assert(a->to->tmp != NULL);
- cparc(nfa, a, s->tmp, a->to->tmp);
- }
-}
-
-/*
- - cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set
- ^ static void cleartraverse(struct nfa *, struct state *);
- */
-static void
-cleartraverse(
- struct nfa *nfa,
- struct state *s)
-{
- struct arc *a;
-
- if (s->tmp == NULL) {
- return;
- }
- s->tmp = NULL;
-
- for (a=s->outs ; a!=NULL ; a=a->outchain) {
- cleartraverse(nfa, a->to);
- }
-}
-
-/*
- - specialcolors - fill in special colors for an NFA
- ^ static void specialcolors(struct nfa *);
- */
-static void
-specialcolors(
- struct nfa *nfa)
-{
- /*
- * False colors for BOS, BOL, EOS, EOL
- */
-
- if (nfa->parent == NULL) {
- nfa->bos[0] = pseudocolor(nfa->cm);
- nfa->bos[1] = pseudocolor(nfa->cm);
- nfa->eos[0] = pseudocolor(nfa->cm);
- nfa->eos[1] = pseudocolor(nfa->cm);
- } else {
- assert(nfa->parent->bos[0] != COLORLESS);
- nfa->bos[0] = nfa->parent->bos[0];
- assert(nfa->parent->bos[1] != COLORLESS);
- nfa->bos[1] = nfa->parent->bos[1];
- assert(nfa->parent->eos[0] != COLORLESS);
- nfa->eos[0] = nfa->parent->eos[0];
- assert(nfa->parent->eos[1] != COLORLESS);
- nfa->eos[1] = nfa->parent->eos[1];
- }
-}
-
-/*
- - optimize - optimize an NFA
- ^ static long 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,
- FILE *f) /* for debug output; NULL none */
-{
- int verbose = (f != NULL) ? 1 : 0;
-
- if (verbose) {
- fprintf(f, "\ninitial cleanup:\n");
- }
- cleanup(nfa); /* may simplify situation */
- if (verbose) {
- dumpnfa(nfa, f);
- }
- if (verbose) {
- fprintf(f, "\nempties:\n");
- }
- fixempties(nfa, f); /* get rid of EMPTY arcs */
- 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 eliminate them
- ^ static void pullback(struct nfa *, FILE *);
- */
-static void
-pullback(
- struct nfa *nfa,
- FILE *f) /* for debug output; NULL none */
-{
- struct state *s;
- struct state *nexts;
- struct arc *a;
- struct arc *nexta;
- struct state *intermediates;
- int progress;
-
- /*
- * Find and pull until there are no more.
- */
-
- do {
- progress = 0;
- for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) {
- nexts = s->next;
- intermediates = NULL;
- for (a=s->outs ; a!=NULL && !NISERR() ; a=nexta) {
- nexta = a->outchain;
- if (a->type == '^' || a->type == BEHIND) {
- 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);
- }
- } while (progress && !NISERR());
- if (NISERR()) {
- 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 == '^') {
- assert(a->co == 0 || a->co == 1);
- newarc(nfa, PLAIN, nfa->bos[a->co], a->from, a->to);
- freearc(nfa, a);
- }
- }
-}
-
-/*
- - pull - pull a back constraint backward past its source state
- *
- * 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
-pull(
- struct nfa *nfa,
- struct arc *con,
- struct state **intermediates)
-{
- struct state *from = con->from;
- struct state *to = con->to;
- struct arc *a;
- struct arc *nexta;
- struct state *s;
-
- assert(from != to); /* should have gotten rid of this earlier */
- if (from->flag) { /* can't pull back beyond start */
- return 0;
- }
- if (from->nins == 0) { /* unreachable */
- freearc(nfa, con);
- return 1;
- }
-
- /*
- * 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) {
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
- }
- 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;
- }
- assert(from->nouts == 1);
-
- /*
- * Propagate the constraint into the from state's inarcs.
- */
-
- for (a=from->ins ; a!=NULL && !NISERR(); a=nexta) {
- nexta = a->inchain;
- switch (combine(con, a)) {
- case INCOMPATIBLE: /* destroy the arc */
- freearc(nfa, a);
- break;
- case SATISFIED: /* no action needed */
- break;
- case COMPATIBLE: /* swap the two arcs, more or less */
- /* 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;
- }
- }
- if (s == NULL) {
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
- }
- s->tmp = *intermediates;
- *intermediates = s;
- }
- cparc(nfa, con, a->from, s);
- cparc(nfa, a, s, to);
- freearc(nfa, a);
- break;
- default:
- assert(NOTREACHED);
- break;
- }
- }
-
- /*
- * Remaining inarcs, if any, incorporate the constraint.
- */
-
- moveins(nfa, from, to);
- 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 eliminate them
- ^ static void pushfwd(struct nfa *, FILE *);
- */
-static void
-pushfwd(
- struct nfa *nfa,
- FILE *f) /* for debug output; NULL none */
-{
- struct state *s;
- struct state *nexts;
- struct arc *a;
- struct arc *nexta;
- struct state *intermediates;
- int progress;
-
- /*
- * Find and push until there are no more.
- */
-
- do {
- progress = 0;
- for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) {
- nexts = s->next;
- intermediates = NULL;
- for (a = s->ins; a != NULL && !NISERR(); a = nexta) {
- nexta = a->inchain;
- if (a->type == '$' || a->type == AHEAD) {
- if (push(nfa, a, &intermediates)) {
- progress = 1;
- }
- }
- }
- /* 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);
- }
- } while (progress && !NISERR());
- if (NISERR()) {
- 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 == '$') {
- assert(a->co == 0 || a->co == 1);
- newarc(nfa, PLAIN, nfa->eos[a->co], a->from, a->to);
- freearc(nfa, a);
- }
- }
-}
-
-/*
- - push - push a forward constraint forward past its destination state
- *
- * 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
-push(
- struct nfa *nfa,
- struct arc *con,
- struct state **intermediates)
-{
- struct state *from = con->from;
- struct state *to = con->to;
- struct arc *a;
- struct arc *nexta;
- struct state *s;
-
- assert(to != from); /* should have gotten rid of this earlier */
- if (to->flag) { /* can't push forward beyond end */
- return 0;
- }
- if (to->nouts == 0) { /* dead end */
- freearc(nfa, con);
- return 1;
- }
-
- /*
- * 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) {
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
- }
- 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;
- }
- assert(to->nins == 1);
-
- /*
- * Propagate the constraint into the to state's outarcs.
- */
-
- for (a = to->outs; a != NULL && !NISERR(); a = nexta) {
- nexta = a->outchain;
- switch (combine(con, a)) {
- case INCOMPATIBLE: /* destroy the arc */
- freearc(nfa, a);
- break;
- case SATISFIED: /* no action needed */
- break;
- case COMPATIBLE: /* swap the two arcs, more or less */
- /* 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;
- }
- }
- if (s == NULL) {
- s = newstate(nfa);
- if (NISERR()) {
- return 0;
- }
- s->tmp = *intermediates;
- *intermediates = s;
- }
- cparc(nfa, con, s, a->to);
- cparc(nfa, a, from, s);
- freearc(nfa, a);
- break;
- default:
- assert(NOTREACHED);
- break;
- }
- }
-
- /*
- * Remaining outarcs, if any, incorporate the constraint.
- */
-
- moveouts(nfa, to, from);
- freearc(nfa, con);
- /* to state is now useless, but we leave it to pushfwd() to clean up */
- return 1;
-}
-
-/*
- - combine - constraint lands on an arc, what happens?
- ^ #def INCOMPATIBLE 1 // destroys arc
- ^ #def SATISFIED 2 // constraint satisfied
- ^ #def COMPATIBLE 3 // compatible but not satisfied yet
- ^ static int combine(struct arc *, struct arc *);
- */
-static int
-combine(
- struct arc *con,
- struct arc *a)
-{
-#define CA(ct,at) (((ct)<<CHAR_BIT) | (at))
-
- switch (CA(con->type, a->type)) {
- case CA('^', PLAIN): /* newlines are handled separately */
- case CA('$', PLAIN):
- return INCOMPATIBLE;
- break;
- case CA(AHEAD, PLAIN): /* color constraints meet colors */
- case CA(BEHIND, PLAIN):
- if (con->co == a->co) {
- return SATISFIED;
- }
- return INCOMPATIBLE;
- break;
- case CA('^', '^'): /* collision, similar constraints */
- case CA('$', '$'):
- case CA(AHEAD, AHEAD):
- case CA(BEHIND, BEHIND):
- if (con->co == a->co) { /* true duplication */
- return SATISFIED;
- }
- return INCOMPATIBLE;
- break;
- case CA('^', BEHIND): /* collision, dissimilar constraints */
- case CA(BEHIND, '^'):
- case CA('$', AHEAD):
- case CA(AHEAD, '$'):
- return INCOMPATIBLE;
- break;
- case CA('^', '$'): /* constraints passing each other */
- case CA('^', AHEAD):
- case CA(BEHIND, '$'):
- case CA(BEHIND, AHEAD):
- case CA('$', '^'):
- case CA('$', BEHIND):
- case CA(AHEAD, '^'):
- case CA(AHEAD, BEHIND):
- case CA('^', LACON):
- case CA(BEHIND, LACON):
- case CA('$', LACON):
- case CA(AHEAD, LACON):
- return COMPATIBLE;
- break;
- }
- assert(NOTREACHED);
- return INCOMPATIBLE; /* for benefit of blind compilers */
-}
-
-/*
- - fixempties - get rid of EMPTY arcs
- ^ static void fixempties(struct nfa *, FILE *);
- */
-static void
-fixempties(
- struct nfa *nfa,
- FILE *f) /* for debug output; NULL none */
-{
- struct state *s;
- struct state *s2;
- 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,
- * since they're basically just aliases for their successor. The
- * parsing algorithm creates enough of these that it's worth
- * special-casing this.
- */
- for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
- nexts = s->next;
- if (s->flag || s->nouts != 1) {
- continue;
- }
- a = s->outs;
- assert(a != NULL && a->outchain == NULL);
- if (a->type != EMPTY) {
- continue;
- }
- if (s != a->to) {
- moveins(nfa, s, a->to);
- }
- dropstate(nfa, s);
- }
-
- /*
- * Similarly, get rid of any state with a single EMPTY in-arc, by
- * folding it into its predecessor.
- */
- for (s = nfa->states; s != NULL && !NISERR(); s = nexts) {
- nexts = s->next;
- /* Ensure tmp fields are clear for next step */
- assert(s->tmp == NULL);
- if (s->flag || s->nins != 1) {
- continue;
- }
- a = s->ins;
- assert(a != NULL && a->inchain == NULL);
- if (a->type != EMPTY) {
- continue;
- }
- if (s != a->from) {
- moveouts(nfa, s, a->from);
- }
- dropstate(nfa, s);
- }
-
- if (NISERR()) {
- return;
- }
-
- /*
- * 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.
- *
- * 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) {
- /* Ignore target states without non-EMPTY outarcs, per note above */
- if (!s->flag && !hasnonemptyout(s)) {
- continue;
- }
-
- /* 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;
- }
- inarcsorig[s->no] = a;
- }
-
- FREE(arcarray);
- FREE(inarcsorig);
-
- if (NISERR()) {
- return;
- }
-
- /*
- * Remove all the EMPTY arcs, since we don't need them anymore.
- */
- for (s = nfa->states; s != NULL; s = s->next) {
- for (a = s->outs; a != NULL; a = nexta) {
- nexta = a->outchain;
- if (a->type == EMPTY) {
- freearc(nfa, a);
- }
- }
- }
-
- /*
- * And remove any states that have become useless. (This cleanup is
- * not very thorough, and would be even less so if we tried to
- * combine it with the previous step; but cleanup() will take care
- * of anything we miss.)
- */
- for (s = nfa->states; s != NULL; s = nexts) {
- nexts = s->next;
- if ((s->nins == 0 || s->nouts == 0) && !s->flag) {
- dropstate(nfa, s);
- }
- }
-
- if (f != NULL) {
- dumpnfa(nfa, f);
- }
-}
-
-/*
- - 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 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 arc **inarcsorig)
-{
- struct arc *a;
-
- s->tmp = lastfound;
- lastfound = s;
- 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;
-}
-
-/*
- * 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
-fixconstraintloops(
- struct nfa * nfa,
- FILE *f) /* for debug output; NULL none */
-{
- 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;
- }
- }
-
- if (NISERR()) {
- return;
- }
-
- /*
- * 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.)
- *
- * 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.)
- */
- for (s = nfa->states; s != NULL; s = s->next) {
- s->tmp = NULL;
- }
-
- /*
- * Recursively build clone state(s) as needed.
- */
- sclone = newstate(nfa);
- if (sclone == NULL) {
- assert(NISERR());
- return;
- }
-
- clonesuccessorstates(nfa, stail, sclone, shead, refarc,
- NULL, NULL, nfa->nstates);
-
- if (NISERR()) {
- return;
- }
-
- /*
- * 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 (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;
- }
-
- /* 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);
- }
-}
-
-/*
- - cleanup - clean up NFA after optimizations
- ^ static void cleanup(struct nfa *);
- */
-static void
-cleanup(
- struct nfa *nfa)
-{
- struct state *s;
- struct state *nexts;
- int n;
-
- /*
- * Clear out unreachable or dead-end states. Use pre to mark reachable,
- * then post to mark can-reach-post.
- */
-
- markreachable(nfa, nfa->pre, NULL, nfa->pre);
- markcanreach(nfa, nfa->post, nfa->pre, nfa->post);
- for (s = nfa->states; s != NULL; s = nexts) {
- nexts = s->next;
- if (s->tmp != nfa->post && !s->flag) {
- dropstate(nfa, s);
- }
- }
- assert(nfa->post->nins == 0 || nfa->post->tmp == nfa->post);
- cleartraverse(nfa, nfa->pre);
- assert(nfa->post->nins == 0 || nfa->post->tmp == NULL);
- /* the nins==0 (final unreachable) case will be caught later */
-
- /*
- * Renumber surviving states.
- */
-
- n = 0;
- for (s = nfa->states; s != NULL; s = s->next) {
- s->no = n++;
- }
- nfa->nstates = n;
-}
-
-/*
- - markreachable - recursive marking of reachable states
- ^ static void markreachable(struct nfa *, struct state *, struct state *,
- ^ struct state *);
- */
-static void
-markreachable(
- struct nfa *nfa,
- struct state *s,
- struct state *okay, /* consider only states with this mark */
- struct state *mark) /* the value to mark with */
-{
- struct arc *a;
-
- if (s->tmp != okay) {
- return;
- }
- s->tmp = mark;
-
- for (a = s->outs; a != NULL; a = a->outchain) {
- markreachable(nfa, a->to, okay, mark);
- }
-}
-
-/*
- - markcanreach - recursive marking of states which can reach here
- ^ static void markcanreach(struct nfa *, struct state *, struct state *,
- ^ struct state *);
- */
-static void
-markcanreach(
- struct nfa *nfa,
- struct state *s,
- struct state *okay, /* consider only states with this mark */
- struct state *mark) /* the value to mark with */
-{
- struct arc *a;
-
- if (s->tmp != okay) {
- return;
- }
- s->tmp = mark;
-
- for (a = s->ins; a != NULL; a = a->inchain) {
- markcanreach(nfa, a->from, okay, mark);
- }
-}
-
-/*
- - analyze - ascertain potentially-useful facts about an optimized NFA
- ^ static long analyze(struct nfa *);
- */
-static long /* re_info bits to be ORed in */
-analyze(
- struct nfa *nfa)
-{
- struct arc *a;
- struct arc *aa;
-
- if (nfa->pre->outs == NULL) {
- return REG_UIMPOSSIBLE;
- }
- for (a = nfa->pre->outs; a != NULL; a = a->outchain) {
- for (aa = a->to->outs; aa != NULL; aa = aa->outchain) {
- if (aa->to == nfa->post) {
- return REG_UEMPTYMATCH;
- }
- }
- }
- return 0;
-}
-
-/*
- - compact - construct the compact representation of an NFA
- ^ static void compact(struct nfa *, struct cnfa *);
- */
-static void
-compact(
- struct nfa *nfa,
- struct cnfa *cnfa)
-{
- struct state *s;
- struct arc *a;
- size_t nstates;
- size_t narcs;
- struct carc *ca;
- struct carc *first;
-
- assert(!NISERR());
-
- nstates = 0;
- narcs = 0;
- for (s = nfa->states; s != NULL; s = s->next) {
- nstates++;
- narcs += s->nouts + 1; /* need one extra for endmarker */
- }
-
- cnfa->stflags = (char *) MALLOC(nstates * sizeof(char));
- cnfa->states = (struct carc **) MALLOC(nstates * sizeof(struct carc *));
- cnfa->arcs = (struct carc *) MALLOC(narcs * sizeof(struct carc));
- if (cnfa->stflags == NULL || cnfa->states == NULL || cnfa->arcs == NULL) {
- if (cnfa->stflags != NULL) {
- FREE(cnfa->stflags);
- }
- if (cnfa->states != NULL) {
- FREE(cnfa->states);
- }
- if (cnfa->arcs != NULL) {
- FREE(cnfa->arcs);
- }
- NERR(REG_ESPACE);
- return;
- }
- cnfa->nstates = nstates;
- cnfa->pre = nfa->pre->no;
- cnfa->post = nfa->post->no;
- cnfa->bos[0] = nfa->bos[0];
- cnfa->bos[1] = nfa->bos[1];
- cnfa->eos[0] = nfa->eos[0];
- cnfa->eos[1] = nfa->eos[1];
- cnfa->ncolors = maxcolor(nfa->cm) + 1;
- cnfa->flags = 0;
-
- ca = cnfa->arcs;
- for (s = nfa->states; s != NULL; s = s->next) {
- assert((size_t) s->no < nstates);
- cnfa->stflags[s->no] = 0;
- cnfa->states[s->no] = ca;
- first = ca;
- for (a = s->outs; a != NULL; a = a->outchain) {
- switch (a->type) {
- case PLAIN:
- ca->co = a->co;
- ca->to = a->to->no;
- ca++;
- break;
- case LACON:
- assert(s->no != cnfa->pre);
- ca->co = (color) (cnfa->ncolors + a->co);
- ca->to = a->to->no;
- ca++;
- cnfa->flags |= HASLACONS;
- break;
- default:
- NERR(REG_ASSERT);
- break;
- }
- }
- carcsort(first, ca - first);
- ca->co = COLORLESS;
- ca->to = 0;
- ca++;
- }
- assert(ca == &cnfa->arcs[narcs]);
- assert(cnfa->nstates != 0);
-
- /*
- * Mark no-progress states.
- */
-
- for (a = nfa->pre->outs; a != NULL; a = a->outchain) {
- cnfa->stflags[a->to->no] = CNFA_NOPROGRESS;
- }
- cnfa->stflags[nfa->pre->no] = CNFA_NOPROGRESS;
-}
-
-/*
- - carcsort - sort compacted-NFA arcs by color
- ^ static void carcsort(struct carc *, struct carc *);
- */
-static void
-carcsort(
- struct carc *first,
- size_t n)
-{
- if (n > 1) {
- qsort(first, n, sizeof(struct carc), carc_cmp);
- }
-}
-
-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;
-}
-
-/*
- - freecnfa - free a compacted NFA
- ^ static void freecnfa(struct cnfa *);
- */
-static void
-freecnfa(
- struct cnfa *cnfa)
-{
- assert(cnfa->nstates != 0); /* not empty already */
- cnfa->nstates = 0;
- FREE(cnfa->stflags);
- FREE(cnfa->states);
- FREE(cnfa->arcs);
-}
-
-/*
- - dumpnfa - dump an NFA in human-readable form
- ^ static void dumpnfa(struct nfa *, FILE *);
- */
-static void
-dumpnfa(
- struct nfa *nfa,
- FILE *f)
-{
-#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) {
- fprintf(f, ", bos [%ld]", (long) nfa->bos[0]);
- }
- if (nfa->bos[1] != COLORLESS) {
- fprintf(f, ", bol [%ld]", (long) nfa->bos[1]);
- }
- if (nfa->eos[0] != COLORLESS) {
- fprintf(f, ", eos [%ld]", (long) nfa->eos[0]);
- }
- if (nfa->eos[1] != COLORLESS) {
- fprintf(f, ", eol [%ld]", (long) nfa->eos[1]);
- }
- fprintf(f, "\n");
- for (s = nfa->states; s != NULL; s = s->next) {
- dumpstate(s, f);
- nstates++;
- narcs += s->nouts;
- }
- fprintf(f, "total of %d states, %d arcs\n", nstates, narcs);
- if (nfa->parent == NULL) {
- dumpcolors(nfa->cm, f);
- }
- fflush(f);
-#endif
-}
-
-#ifdef REG_DEBUG /* subordinates of dumpnfa */
-/*
- ^ #ifdef REG_DEBUG
- */
-
-/*
- - dumpstate - dump an NFA state in human-readable form
- ^ static void dumpstate(struct state *, FILE *);
- */
-static void
-dumpstate(
- struct state *s,
- FILE *f)
-{
- struct arc *a;
-
- fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "",
- (s->flag) ? s->flag : '.');
- if (s->prev != NULL && s->prev->next != s) {
- fprintf(f, "\tstate chain bad\n");
- }
- if (s->nouts == 0) {
- fprintf(f, "\tno out arcs\n");
- } else {
- dumparcs(s, f);
- }
- fflush(f);
- for (a = s->ins; a != NULL; a = a->inchain) {
- if (a->to != s) {
- fprintf(f, "\tlink from %d to %d on %d's in-chain\n",
- a->from->no, a->to->no, s->no);
- }
- }
-}
-
-/*
- - dumparcs - dump out-arcs in human-readable form
- ^ static void dumparcs(struct state *, FILE *);
- */
-static void
-dumparcs(
- struct state *s,
- FILE *f)
-{
- int pos;
- struct arc *a;
-
- /* printing oldest arcs first is usually clearer */
- a = s->outs;
- assert(a != NULL);
- while (a->outchain != NULL) {
- a = a->outchain;
- }
- 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");
- }
-}
-
-/*
- - dumparc - dump one outarc in readable form, including prefixing tab
- ^ static void dumparc(struct arc *, struct state *, FILE *);
- */
-static void
-dumparc(
- struct arc *a,
- struct state *s,
- FILE *f)
-{
- struct arc *aa;
- struct arcbatch *ab;
-
- fprintf(f, "\t");
- switch (a->type) {
- case PLAIN:
- fprintf(f, "[%ld]", (long) a->co);
- break;
- case AHEAD:
- fprintf(f, ">%ld>", (long) a->co);
- break;
- case BEHIND:
- fprintf(f, "<%ld<", (long) a->co);
- break;
- case LACON:
- fprintf(f, ":%ld:", (long) a->co);
- break;
- case '^':
- case '$':
- fprintf(f, "%c%d", a->type, (int) a->co);
- break;
- case EMPTY:
- break;
- default:
- fprintf(f, "0x%x/0%lo", a->type, (long) a->co);
- break;
- }
- if (a->from != s) {
- fprintf(f, "?%d?", a->from->no);
- }
- for (ab = &a->from->oas; ab != NULL; ab = ab->next) {
- for (aa = &ab->a[0]; aa < &ab->a[ABSIZE]; aa++) {
- if (aa == a) {
- break; /* NOTE BREAK OUT */
- }
- }
- if (aa < &ab->a[ABSIZE]) { /* propagate break */
- break; /* NOTE BREAK OUT */
- }
- }
- if (ab == NULL) {
- fprintf(f, "?!?"); /* not in allocated space */
- }
- fprintf(f, "->");
- if (a->to == NULL) {
- fprintf(f, "NULL");
- return;
- }
- fprintf(f, "%d", a->to->no);
- for (aa = a->to->ins; aa != NULL; aa = aa->inchain) {
- if (aa == a) {
- break; /* NOTE BREAK OUT */
- }
- }
- if (aa == NULL) {
- fprintf(f, "?!?"); /* missing from in-chain */
- }
-}
-
-/*
- ^ #endif
- */
-#endif /* ifdef REG_DEBUG */
-
-/*
- - dumpcnfa - dump a compacted NFA in human-readable form
- ^ static void dumpcnfa(struct cnfa *, FILE *);
- */
-static void
-dumpcnfa(
- struct cnfa *cnfa,
- FILE *f)
-{
-#ifdef REG_DEBUG
- int st;
-
- fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post);
- if (cnfa->bos[0] != COLORLESS) {
- fprintf(f, ", bos [%ld]", (long) cnfa->bos[0]);
- }
- if (cnfa->bos[1] != COLORLESS) {
- fprintf(f, ", bol [%ld]", (long) cnfa->bos[1]);
- }
- if (cnfa->eos[0] != COLORLESS) {
- fprintf(f, ", eos [%ld]", (long) cnfa->eos[0]);
- }
- if (cnfa->eos[1] != COLORLESS) {
- fprintf(f, ", eol [%ld]", (long) cnfa->eos[1]);
- }
- if (cnfa->flags&HASLACONS) {
- fprintf(f, ", haslacons");
- }
- fprintf(f, "\n");
- for (st = 0; st < cnfa->nstates; st++) {
- dumpcstate(st, cnfa, f);
- }
- fflush(f);
-#endif
-}
-
-#ifdef REG_DEBUG /* subordinates of dumpcnfa */
-/*
- ^ #ifdef REG_DEBUG
- */
-
-/*
- - dumpcstate - dump a compacted-NFA state in human-readable form
- ^ static void dumpcstate(int, struct cnfa *, FILE *);
- */
-static void
-dumpcstate(
- int st,
- struct cnfa *cnfa,
- FILE *f)
-{
- struct carc *ca;
- int pos;
-
- fprintf(f, "%d%s", st, (cnfa->stflags[st] & CNFA_NOPROGRESS) ? ":" : ".");
- pos = 1;
- for (ca = cnfa->states[st]; ca->co != COLORLESS; ca++) {
- if (ca->co < cnfa->ncolors) {
- fprintf(f, "\t[%ld]->%d", (long) ca->co, ca->to);
- } else {
- fprintf(f, "\t:%ld:->%d", (long) (ca->co - cnfa->ncolors), ca->to);
- }
- if (pos == 5) {
- fprintf(f, "\n");
- pos = 1;
- } else {
- pos++;
- }
- }
- if (ca == cnfa->states[st] || pos != 1) {
- fprintf(f, "\n");
- }
- fflush(f);
-}
-
-/*
- ^ #endif
- */
-#endif /* ifdef REG_DEBUG */
-
-/*
- * Local Variables:
- * mode: c
- * c-basic-offset: 4
- * fill-column: 78
- * End:
- */