/* * 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->size = 0; nfa->bos[0] = nfa->bos[1] = COLORLESS; nfa->eos[0] = nfa->eos[1] = COLORLESS; nfa->parent = parent; /* Precedes newfstate so parent is valid. */ nfa->post = newfstate(nfa, '@'); /* number 0 */ nfa->pre = newfstate(nfa, '>'); /* number 1 */ nfa->init = newstate(nfa); /* May become invalid later. */ nfa->final = newstate(nfa); if (ISERR()) { freenfa(nfa); return NULL; } rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init); newarc(nfa, '^', 1, nfa->pre, nfa->init); newarc(nfa, '^', 0, nfa->pre, nfa->init); rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post); newarc(nfa, '$', 1, nfa->final, nfa->post); newarc(nfa, '$', 0, nfa->final, nfa->post); if (ISERR()) { freenfa(nfa); return NULL; } return nfa; } /* - TooManyStates - checks if the max states exceeds the compile-time value ^ static int TooManyStates(struct nfa *); */ static int TooManyStates( struct nfa *nfa) { struct nfa *parent = nfa->parent; size_t sz = nfa->size; while (parent != NULL) { sz = parent->size; parent = parent->parent; } if (sz > REG_MAX_STATES) { return 1; } return 0; } /* - IncrementSize - increases the tracked size of the NFA and its parents. ^ static void IncrementSize(struct nfa *); */ static void IncrementSize( struct nfa *nfa) { struct nfa *parent = nfa->parent; nfa->size++; while (parent != NULL) { parent->size++; parent = parent->parent; } } /* - DecrementSize - increases the tracked size of the NFA and its parents. ^ static void DecrementSize(struct nfa *); */ static void DecrementSize( struct nfa *nfa) { struct nfa *parent = nfa->parent; nfa->size--; while (parent != NULL) { parent->size--; parent = parent->parent; } } /* - freenfa - free an entire NFA ^ static VOID freenfa(struct nfa *); */ 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 (TooManyStates(nfa)) { /* XXX: add specific error for this */ NERR(REG_ETOOBIG); return NULL; } if (nfa->free != NULL) { s = nfa->free; nfa->free = s->next; } else { s = (struct state *) MALLOC(sizeof(struct state)); if (s == NULL) { NERR(REG_ESPACE); return NULL; } s->oas.next = NULL; s->free = NULL; s->noas = 0; } assert(nfa->nstates >= 0); s->no = nfa->nstates++; s->flag = 0; if (nfa->states == NULL) { nfa->states = s; } s->nins = 0; s->ins = NULL; s->nouts = 0; s->outs = NULL; s->tmp = NULL; s->next = NULL; if (nfa->slast != NULL) { assert(nfa->slast->next == NULL); nfa->slast->next = s; } s->prev = nfa->slast; nfa->slast = s; /* * Track the current size and the parent size. */ IncrementSize(nfa); return s; } /* - newfstate - allocate an NFA state with a specified flag value ^ static struct state *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; DecrementSize(nfa); } /* - 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); } s->ins = NULL; s->outs = NULL; s->next = NULL; FREE(s); } /* - newarc - set up a new arc within an NFA ^ static VOID newarc(struct nfa *, 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 = (struct arcbatch *) MALLOC(sizeof(struct arcbatch)); int i; if (newAb == NULL) { NERR(REG_ESPACE); return NULL; } newAb->next = s->oas.next; s->oas.next = newAb; for (i=0 ; ia[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 * Either all arcs, or only non-empty ones as determined by all value. ^ static VOID copyins(struct nfa *, struct state *, struct state *, int); */ static void copyins( struct nfa *nfa, struct state *oldState, struct state *newState, int all) { 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) { if (all || a->type != EMPTY) { 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; if (!all && a->type == EMPTY) { oa = oa->inchain; continue; } 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; if (!all && a->type == EMPTY) { oa = oa->inchain; continue; } 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 * Either all arcs, or only non-empty ones as determined by all value. ^ static VOID copyouts(struct nfa *, struct state *, struct state *, int); */ static void copyouts( struct nfa *nfa, struct state *oldState, struct state *newState, int all) { 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) { if (all || a->type != EMPTY) { 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; if (!all && a->type == EMPTY) { oa = oa->outchain; continue; } 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; if (!all && a->type == EMPTY){ oa = oa->outchain; continue; } 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); /* 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 */ { struct arc *a; if (s->tmp != NULL) { return; /* already done */ } s->tmp = (stmp == NULL) ? newstate(nfa) : stmp; if (s->tmp == NULL) { assert(NISERR()); return; } for (a=s->outs ; a!=NULL && !NISERR() ; a=a->outchain) { duptraverse(nfa, a->to, NULL); if (NISERR()) { break; } assert(a->to->tmp != NULL); cparc(nfa, a, s->tmp, a->to->tmp); } } /* - cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set ^ static VOID cleartraverse(struct nfa *, 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 */ 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; int progress; /* * Find and pull until there are no more. */ do { progress = 0; for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) { nexts = s->next; for (a=s->outs ; a!=NULL && !NISERR() ; a=nexta) { nexta = a->outchain; if (a->type == '^' || a->type == BEHIND) { if (pull(nfa, a)) { progress = 1; } } assert(nexta == NULL || s->no != FREESTATE); } } if (progress && f != NULL) { dumpnfa(nfa, f); } } while (progress && !NISERR()); if (NISERR()) { return; } /* * 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 * A significant property of this function is that it deletes at most * one state -- the constraint's from state -- and only if the constraint * was that state's last outarc. ^ static int pull(struct nfa *, struct arc *); */ static int /* 0 couldn't, 1 could */ pull( struct nfa *nfa, struct arc *con) { struct state *from = con->from; struct state *to = con->to; struct arc *a; struct arc *nexta; struct state *s; 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. */ if (from->nouts > 1) { s = newstate(nfa); if (NISERR()) { return 0; } copyins(nfa, from, s, 1); /* duplicate inarcs */ cparc(nfa, con, s, to); /* move constraint arc */ freearc(nfa, con); from = s; con = from->outs; } assert(from->nouts == 1); /* * Propagate the constraint into the from state's inarcs. */ for (a=from->ins ; a!=NULL ; a=nexta) { nexta = a->inchain; switch (combine(con, a)) { case INCOMPATIBLE: /* destroy the arc */ freearc(nfa, a); break; case SATISFIED: /* no action needed */ break; case COMPATIBLE: /* swap the two arcs, more or less */ s = newstate(nfa); if (NISERR()) { return 0; } cparc(nfa, a, s, to); /* anticipate move */ cparc(nfa, con, a->from, s); if (NISERR()) { return 0; } freearc(nfa, a); break; default: assert(NOTREACHED); break; } } /* * Remaining inarcs, if any, incorporate the constraint. */ moveins(nfa, from, to); dropstate(nfa, from); /* will free the constraint */ return 1; } /* - pushfwd - push forward constraints forward to 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; int progress; /* * Find and push until there are no more. */ do { progress = 0; for (s=nfa->states ; s!=NULL && !NISERR() ; s=nexts) { nexts = s->next; for (a = s->ins; a != NULL && !NISERR(); a = nexta) { nexta = a->inchain; if (a->type == '$' || a->type == AHEAD) { if (push(nfa, a)) { progress = 1; } } assert(nexta == NULL || s->no != FREESTATE); } } if (progress && f != NULL) { dumpnfa(nfa, f); } } while (progress && !NISERR()); if (NISERR()) { return; } /* * 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 * A significant property of this function is that it deletes at most * one state -- the constraint's to state -- and only if the constraint * was that state's last inarc. ^ static int push(struct nfa *, struct arc *); */ static int /* 0 couldn't, 1 could */ push( struct nfa *nfa, struct arc *con) { struct state *from = con->from; struct state *to = con->to; struct arc *a; struct arc *nexta; struct state *s; 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. */ if (to->nins > 1) { s = newstate(nfa); if (NISERR()) { return 0; } copyouts(nfa, to, s, 1); /* duplicate outarcs */ cparc(nfa, con, from, s); /* move constraint */ freearc(nfa, con); to = s; con = to->ins; } assert(to->nins == 1); /* * Propagate the constraint into the to state's outarcs. */ for (a = to->outs; a != NULL; a = nexta) { nexta = a->outchain; switch (combine(con, a)) { case INCOMPATIBLE: /* destroy the arc */ freearc(nfa, a); break; case SATISFIED: /* no action needed */ break; case COMPATIBLE: /* swap the two arcs, more or less */ s = newstate(nfa); if (NISERR()) { return 0; } cparc(nfa, con, s, a->to); /* anticipate move */ cparc(nfa, a, from, s); if (NISERR()) { return 0; } freearc(nfa, a); break; default: assert(NOTREACHED); break; } } /* * Remaining outarcs, if any, incorporate the constraint. */ moveouts(nfa, to, from); dropstate(nfa, to); /* will free the constraint */ return 1; } /* - 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)<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 += 1 + s->nouts + 1; /* 1 as a fake for flags, nouts for arcs, 1 as endmarker */ } cnfa->states = (struct carc **) MALLOC(nstates * sizeof(struct carc *)); cnfa->arcs = (struct carc *) MALLOC(narcs * sizeof(struct carc)); if (cnfa->states == NULL || cnfa->arcs == NULL) { if (cnfa->states != NULL) { FREE(cnfa->states); } if (cnfa->arcs != NULL) { FREE(cnfa->arcs); } NERR(REG_ESPACE); return; } cnfa->nstates = nstates; cnfa->pre = nfa->pre->no; cnfa->post = nfa->post->no; cnfa->bos[0] = nfa->bos[0]; cnfa->bos[1] = nfa->bos[1]; cnfa->eos[0] = nfa->eos[0]; cnfa->eos[1] = nfa->eos[1]; cnfa->ncolors = maxcolor(nfa->cm) + 1; cnfa->flags = 0; ca = cnfa->arcs; for (s = nfa->states; s != NULL; s = s->next) { assert((size_t) s->no < nstates); cnfa->states[s->no] = ca; ca->co = 0; /* clear and skip flags "arc" */ ca++; first = ca; for (a = s->outs; a != NULL; a = a->outchain) { switch (a->type) { case PLAIN: ca->co = a->co; ca->to = a->to->no; ca++; break; case LACON: assert(s->no != cnfa->pre); ca->co = (color) (cnfa->ncolors + a->co); ca->to = a->to->no; ca++; cnfa->flags |= HASLACONS; break; default: 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->states[a->to->no]->co = 1; } cnfa->states[nfa->pre->no]->co = 1; } /* - 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->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; fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no); if (nfa->bos[0] != COLORLESS) { fprintf(f, ", bos [%ld]", (long) nfa->bos[0]); } if (nfa->bos[1] != COLORLESS) { fprintf(f, ", bol [%ld]", (long) nfa->bos[1]); } if (nfa->eos[0] != COLORLESS) { fprintf(f, ", eos [%ld]", (long) nfa->eos[0]); } if (nfa->eos[1] != COLORLESS) { fprintf(f, ", eol [%ld]", (long) nfa->eos[1]); } fprintf(f, "\n"); for (s = nfa->states; s != NULL; s = s->next) { dumpstate(s, f); } if (nfa->parent == NULL) { dumpcolors(nfa->cm, f); } fflush(f); #endif } #ifdef REG_DEBUG /* subordinates of dumpnfa */ /* ^ #ifdef REG_DEBUG */ /* - 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->states[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 carc *, struct cnfa *, FILE *); */ static void dumpcstate( int st, struct carc *ca, struct cnfa *cnfa, FILE *f) { int i; int pos; fprintf(f, "%d%s", st, (ca[0].co) ? ":" : "."); pos = 1; for (i = 1; ca[i].co != COLORLESS; i++) { if (ca[i].co < cnfa->ncolors) { fprintf(f, "\t[%ld]->%d", (long) ca[i].co, ca[i].to); } else { fprintf(f, "\t:%ld:->%d", (long) ca[i].co-cnfa->ncolors,ca[i].to); } if (pos == 5) { fprintf(f, "\n"); pos = 1; } else { pos++; } } if (i == 1 || pos != 1) { fprintf(f, "\n"); } fflush(f); } /* ^ #endif */ #endif /* ifdef REG_DEBUG */ /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */