3825 lines
98 KiB
C
3825 lines
98 KiB
C
/*
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* NFA utilities.
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* This file is #included by regcomp.c.
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*
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* Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
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*
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* Development of this software was funded, in part, by Cray Research Inc.,
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* UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
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* Corporation, none of whom are responsible for the results. The author
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* thanks all of them.
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*
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* Redistribution and use in source and binary forms -- with or without
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* modification -- are permitted for any purpose, provided that
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* redistributions in source form retain this entire copyright notice and
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* indicate the origin and nature of any modifications.
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*
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* I'd appreciate being given credit for this package in the documentation
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* of software which uses it, but that is not a requirement.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* src/backend/regex/regc_nfa.c
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*
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*
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* One or two things that technically ought to be in here
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* are actually in color.c, thanks to some incestuous relationships in
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* the color chains.
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*/
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#define NISERR() VISERR(nfa->v)
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#define NERR(e) VERR(nfa->v, (e))
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/*
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* newnfa - set up an NFA
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*/
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static struct nfa * /* the NFA, or NULL */
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newnfa(struct vars *v,
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struct colormap *cm,
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struct nfa *parent) /* NULL if primary NFA */
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{
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struct nfa *nfa;
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nfa = (struct nfa *) MALLOC(sizeof(struct nfa));
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if (nfa == NULL)
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{
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ERR(REG_ESPACE);
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return NULL;
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}
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/* Make the NFA minimally valid, so freenfa() will behave sanely */
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nfa->states = NULL;
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nfa->slast = NULL;
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nfa->freestates = NULL;
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nfa->freearcs = NULL;
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nfa->lastsb = NULL;
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nfa->lastab = NULL;
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nfa->lastsbused = 0;
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nfa->lastabused = 0;
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nfa->nstates = 0;
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nfa->cm = cm;
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nfa->v = v;
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nfa->bos[0] = nfa->bos[1] = COLORLESS;
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nfa->eos[0] = nfa->eos[1] = COLORLESS;
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nfa->flags = 0;
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nfa->minmatchall = nfa->maxmatchall = -1;
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nfa->parent = parent; /* Precedes newfstate so parent is valid. */
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/* Create required infrastructure */
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nfa->post = newfstate(nfa, '@'); /* number 0 */
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nfa->pre = newfstate(nfa, '>'); /* number 1 */
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nfa->init = newstate(nfa); /* may become invalid later */
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nfa->final = newstate(nfa);
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if (ISERR())
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{
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freenfa(nfa);
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return NULL;
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}
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rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init);
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newarc(nfa, '^', 1, nfa->pre, nfa->init);
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newarc(nfa, '^', 0, nfa->pre, nfa->init);
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rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post);
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newarc(nfa, '$', 1, nfa->final, nfa->post);
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newarc(nfa, '$', 0, nfa->final, nfa->post);
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if (ISERR())
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{
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freenfa(nfa);
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return NULL;
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}
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return nfa;
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}
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/*
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* freenfa - free an entire NFA
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*/
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static void
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freenfa(struct nfa *nfa)
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{
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struct statebatch *sb;
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struct statebatch *sbnext;
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struct arcbatch *ab;
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struct arcbatch *abnext;
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for (sb = nfa->lastsb; sb != NULL; sb = sbnext)
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{
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sbnext = sb->next;
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nfa->v->spaceused -= STATEBATCHSIZE(sb->nstates);
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FREE(sb);
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}
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nfa->lastsb = NULL;
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for (ab = nfa->lastab; ab != NULL; ab = abnext)
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{
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abnext = ab->next;
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nfa->v->spaceused -= ARCBATCHSIZE(ab->narcs);
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FREE(ab);
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}
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nfa->lastab = NULL;
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nfa->nstates = -1;
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FREE(nfa);
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}
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/*
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* newstate - allocate an NFA state, with zero flag value
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*/
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static struct state * /* NULL on error */
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newstate(struct nfa *nfa)
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{
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struct state *s;
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/*
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* This is a handy place to check for operation cancel during regex
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* compilation, since no code path will go very long without making a new
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* state or arc.
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*/
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if (CANCEL_REQUESTED(nfa->v->re))
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{
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NERR(REG_CANCEL);
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return NULL;
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}
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/* first, recycle anything that's on the freelist */
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if (nfa->freestates != NULL)
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{
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s = nfa->freestates;
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nfa->freestates = s->next;
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}
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/* otherwise, is there anything left in the last statebatch? */
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else if (nfa->lastsb != NULL && nfa->lastsbused < nfa->lastsb->nstates)
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{
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s = &nfa->lastsb->s[nfa->lastsbused++];
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}
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/* otherwise, need to allocate a new statebatch */
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else
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{
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struct statebatch *newSb;
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size_t nstates;
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if (nfa->v->spaceused >= REG_MAX_COMPILE_SPACE)
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{
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NERR(REG_ETOOBIG);
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return NULL;
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}
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nstates = (nfa->lastsb != NULL) ? nfa->lastsb->nstates * 2 : FIRSTSBSIZE;
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if (nstates > MAXSBSIZE)
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nstates = MAXSBSIZE;
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newSb = (struct statebatch *) MALLOC(STATEBATCHSIZE(nstates));
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if (newSb == NULL)
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{
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NERR(REG_ESPACE);
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return NULL;
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}
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nfa->v->spaceused += STATEBATCHSIZE(nstates);
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newSb->nstates = nstates;
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newSb->next = nfa->lastsb;
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nfa->lastsb = newSb;
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nfa->lastsbused = 1;
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s = &newSb->s[0];
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}
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assert(nfa->nstates >= 0);
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s->no = nfa->nstates++;
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s->flag = 0;
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if (nfa->states == NULL)
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nfa->states = s;
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s->nins = 0;
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s->ins = NULL;
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s->nouts = 0;
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s->outs = NULL;
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s->tmp = NULL;
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s->next = NULL;
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if (nfa->slast != NULL)
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{
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assert(nfa->slast->next == NULL);
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nfa->slast->next = s;
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}
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s->prev = nfa->slast;
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nfa->slast = s;
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return s;
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}
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/*
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* newfstate - allocate an NFA state with a specified flag value
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*/
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static struct state * /* NULL on error */
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newfstate(struct nfa *nfa, int flag)
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{
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struct state *s;
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s = newstate(nfa);
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if (s != NULL)
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s->flag = (char) flag;
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return s;
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}
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/*
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* dropstate - delete a state's inarcs and outarcs and free it
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*/
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static void
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dropstate(struct nfa *nfa,
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struct state *s)
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{
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struct arc *a;
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while ((a = s->ins) != NULL)
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freearc(nfa, a);
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while ((a = s->outs) != NULL)
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freearc(nfa, a);
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freestate(nfa, s);
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}
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/*
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* freestate - free a state, which has no in-arcs or out-arcs
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*/
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static void
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freestate(struct nfa *nfa,
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struct state *s)
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{
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assert(s != NULL);
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assert(s->nins == 0 && s->nouts == 0);
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s->no = FREESTATE;
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s->flag = 0;
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if (s->next != NULL)
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s->next->prev = s->prev;
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else
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{
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assert(s == nfa->slast);
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nfa->slast = s->prev;
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}
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if (s->prev != NULL)
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s->prev->next = s->next;
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else
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{
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assert(s == nfa->states);
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nfa->states = s->next;
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}
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s->prev = NULL;
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s->next = nfa->freestates; /* don't delete it, put it on the free list */
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nfa->freestates = s;
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}
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/*
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* newarc - set up a new arc within an NFA
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*
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* This function checks to make sure that no duplicate arcs are created.
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* In general we never want duplicates.
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*
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* However: in principle, a RAINBOW arc is redundant with any plain arc
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* (unless that arc is for a pseudocolor). But we don't try to recognize
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* that redundancy, either here or in allied operations such as moveins().
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* The pseudocolor consideration makes that more costly than it seems worth.
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*/
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static void
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newarc(struct nfa *nfa,
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int t,
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color co,
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struct state *from,
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struct state *to)
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{
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struct arc *a;
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assert(from != NULL && to != NULL);
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/*
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* This is a handy place to check for operation cancel during regex
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* compilation, since no code path will go very long without making a new
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* state or arc.
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*/
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if (CANCEL_REQUESTED(nfa->v->re))
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{
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NERR(REG_CANCEL);
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return;
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}
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/* check for duplicate arc, using whichever chain is shorter */
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if (from->nouts <= to->nins)
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{
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for (a = from->outs; a != NULL; a = a->outchain)
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if (a->to == to && a->co == co && a->type == t)
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return;
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}
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else
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{
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for (a = to->ins; a != NULL; a = a->inchain)
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if (a->from == from && a->co == co && a->type == t)
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return;
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}
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/* no dup, so create the arc */
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createarc(nfa, t, co, from, to);
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}
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/*
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* createarc - create a new arc within an NFA
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*
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* This function must *only* be used after verifying that there is no existing
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* identical arc (same type/color/from/to).
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*/
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static void
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createarc(struct nfa *nfa,
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int t,
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color co,
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struct state *from,
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struct state *to)
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{
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struct arc *a;
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a = allocarc(nfa);
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if (NISERR())
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return;
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assert(a != NULL);
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a->type = t;
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a->co = co;
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a->to = to;
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a->from = from;
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/*
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* Put the new arc on the beginning, not the end, of the chains; it's
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* simpler here, and freearc() is the same cost either way. See also the
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* logic in moveins() and its cohorts, as well as fixempties().
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*/
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a->inchain = to->ins;
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a->inchainRev = NULL;
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if (to->ins)
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to->ins->inchainRev = a;
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to->ins = a;
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a->outchain = from->outs;
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a->outchainRev = NULL;
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if (from->outs)
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from->outs->outchainRev = a;
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from->outs = a;
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from->nouts++;
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to->nins++;
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if (COLORED(a) && nfa->parent == NULL)
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colorchain(nfa->cm, a);
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}
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/*
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* allocarc - allocate a new arc within an NFA
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*/
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static struct arc * /* NULL for failure */
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allocarc(struct nfa *nfa)
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{
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struct arc *a;
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/* first, recycle anything that's on the freelist */
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if (nfa->freearcs != NULL)
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{
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a = nfa->freearcs;
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nfa->freearcs = a->freechain;
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}
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/* otherwise, is there anything left in the last arcbatch? */
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else if (nfa->lastab != NULL && nfa->lastabused < nfa->lastab->narcs)
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{
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a = &nfa->lastab->a[nfa->lastabused++];
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}
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/* otherwise, need to allocate a new arcbatch */
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else
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{
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struct arcbatch *newAb;
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size_t narcs;
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if (nfa->v->spaceused >= REG_MAX_COMPILE_SPACE)
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{
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NERR(REG_ETOOBIG);
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return NULL;
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}
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narcs = (nfa->lastab != NULL) ? nfa->lastab->narcs * 2 : FIRSTABSIZE;
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if (narcs > MAXABSIZE)
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narcs = MAXABSIZE;
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newAb = (struct arcbatch *) MALLOC(ARCBATCHSIZE(narcs));
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if (newAb == NULL)
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{
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NERR(REG_ESPACE);
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return NULL;
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}
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nfa->v->spaceused += ARCBATCHSIZE(narcs);
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newAb->narcs = narcs;
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newAb->next = nfa->lastab;
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nfa->lastab = newAb;
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nfa->lastabused = 1;
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a = &newAb->a[0];
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}
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return a;
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}
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/*
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* freearc - free an arc
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*/
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static void
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freearc(struct nfa *nfa,
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struct arc *victim)
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{
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struct state *from = victim->from;
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struct state *to = victim->to;
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struct arc *predecessor;
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assert(victim->type != 0);
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/* take it off color chain if necessary */
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if (COLORED(victim) && nfa->parent == NULL)
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uncolorchain(nfa->cm, victim);
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/* take it off source's out-chain */
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assert(from != NULL);
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predecessor = victim->outchainRev;
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if (predecessor == NULL)
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{
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assert(from->outs == victim);
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from->outs = victim->outchain;
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}
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else
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{
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assert(predecessor->outchain == victim);
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predecessor->outchain = victim->outchain;
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}
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if (victim->outchain != NULL)
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{
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assert(victim->outchain->outchainRev == victim);
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victim->outchain->outchainRev = predecessor;
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}
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from->nouts--;
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/* take it off target's in-chain */
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assert(to != NULL);
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predecessor = victim->inchainRev;
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if (predecessor == NULL)
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{
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assert(to->ins == victim);
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to->ins = victim->inchain;
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}
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else
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{
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assert(predecessor->inchain == victim);
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predecessor->inchain = victim->inchain;
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}
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if (victim->inchain != NULL)
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{
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assert(victim->inchain->inchainRev == victim);
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victim->inchain->inchainRev = predecessor;
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}
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to->nins--;
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/* clean up and place on NFA's free list */
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victim->type = 0;
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victim->from = NULL; /* precautions... */
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victim->to = NULL;
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victim->inchain = NULL;
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victim->inchainRev = NULL;
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victim->outchain = NULL;
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victim->outchainRev = NULL;
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victim->freechain = nfa->freearcs;
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nfa->freearcs = victim;
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}
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/*
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* changearcsource - flip an arc to have a different from state
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*
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* Caller must have verified that there is no pre-existing duplicate arc.
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*/
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static void
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changearcsource(struct arc *a, struct state *newfrom)
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{
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struct state *oldfrom = a->from;
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struct arc *predecessor;
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|
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assert(oldfrom != newfrom);
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/* take it off old source's out-chain */
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assert(oldfrom != NULL);
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predecessor = a->outchainRev;
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if (predecessor == NULL)
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{
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assert(oldfrom->outs == a);
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oldfrom->outs = a->outchain;
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}
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else
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{
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assert(predecessor->outchain == a);
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predecessor->outchain = a->outchain;
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}
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if (a->outchain != NULL)
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{
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assert(a->outchain->outchainRev == a);
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a->outchain->outchainRev = predecessor;
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}
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oldfrom->nouts--;
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a->from = newfrom;
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/* prepend it to new source's out-chain */
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a->outchain = newfrom->outs;
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a->outchainRev = NULL;
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if (newfrom->outs)
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newfrom->outs->outchainRev = a;
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newfrom->outs = a;
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newfrom->nouts++;
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}
|
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|
|
/*
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* changearctarget - flip an arc to have a different to state
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*
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* Caller must have verified that there is no pre-existing duplicate arc.
|
|
*/
|
|
static void
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changearctarget(struct arc *a, struct state *newto)
|
|
{
|
|
struct state *oldto = a->to;
|
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struct arc *predecessor;
|
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|
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assert(oldto != newto);
|
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|
|
/* 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 *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 *s,
|
|
int type,
|
|
color 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 *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 *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 *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
|
|
*
|
|
* See comments for moveins()
|
|
*/
|
|
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 changearcsource()
|
|
* 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;
|
|
}
|
|
|
|
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;
|
|
|
|
/*
|
|
* Rather than doing createarc+freearc, we can just unlink
|
|
* and relink the existing arc struct.
|
|
*/
|
|
changearcsource(a, newState);
|
|
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;
|
|
changearcsource(a, newState);
|
|
}
|
|
}
|
|
|
|
assert(oldState->nouts == 0);
|
|
assert(oldState->outs == NULL);
|
|
}
|
|
|
|
/*
|
|
* copyouts - copy out arcs of a state to another state
|
|
*/
|
|
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
|
|
*
|
|
* This is only used to convert PLAIN arcs to AHEAD/BEHIND arcs, which share
|
|
* the same interpretation of "co". It wouldn't be sensible with LACONs.
|
|
*/
|
|
static void
|
|
cloneouts(struct nfa *nfa,
|
|
struct state *old,
|
|
struct state *from,
|
|
struct state *to,
|
|
int type)
|
|
{
|
|
struct arc *a;
|
|
|
|
assert(old != from);
|
|
assert(type == AHEAD || type == BEHIND);
|
|
|
|
for (a = old->outs; a != NULL; a = a->outchain)
|
|
{
|
|
assert(a->type == PLAIN);
|
|
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 *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);
|
|
if (NISERR())
|
|
return; /* asserts might not hold after failure */
|
|
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 *nfa,
|
|
struct state *leftend,
|
|
struct state *s)
|
|
{
|
|
struct arc *a;
|
|
struct state *to;
|
|
|
|
/* Since this is recursive, it could be driven to stack overflow */
|
|
if (STACK_TOO_DEEP(nfa->v->re))
|
|
{
|
|
NERR(REG_ETOOBIG);
|
|
return;
|
|
}
|
|
|
|
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);
|
|
if (NISERR())
|
|
return; /* asserts might not hold after failure */
|
|
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 *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 *nfa,
|
|
struct state *s,
|
|
struct state *stmp) /* s's duplicate, or NULL */
|
|
{
|
|
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 (s->tmp != NULL)
|
|
return; /* already done */
|
|
|
|
s->tmp = (stmp == NULL) ? newstate(nfa) : stmp;
|
|
if (s->tmp == NULL)
|
|
{
|
|
assert(NISERR());
|
|
return;
|
|
}
|
|
|
|
for (a = s->outs; a != NULL && !NISERR(); a = a->outchain)
|
|
{
|
|
duptraverse(nfa, a->to, (struct state *) NULL);
|
|
if (NISERR())
|
|
break;
|
|
assert(a->to->tmp != NULL);
|
|
cparc(nfa, a, s->tmp, a->to->tmp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* removeconstraints - remove any constraints in an NFA
|
|
*
|
|
* Constraint arcs are replaced by empty arcs, essentially treating all
|
|
* constraints as automatically satisfied.
|
|
*/
|
|
static void
|
|
removeconstraints(struct nfa *nfa,
|
|
struct state *start, /* process subNFA starting here */
|
|
struct state *stop) /* and stopping here */
|
|
{
|
|
if (start == stop)
|
|
return;
|
|
|
|
stop->tmp = stop;
|
|
removetraverse(nfa, start);
|
|
/* done, except for clearing out the tmp pointers */
|
|
|
|
stop->tmp = NULL;
|
|
cleartraverse(nfa, start);
|
|
}
|
|
|
|
/*
|
|
* removetraverse - recursive heart of removeconstraints
|
|
*/
|
|
static void
|
|
removetraverse(struct nfa *nfa,
|
|
struct state *s)
|
|
{
|
|
struct arc *a;
|
|
struct arc *oa;
|
|
|
|
/* Since this is recursive, it could be driven to stack overflow */
|
|
if (STACK_TOO_DEEP(nfa->v->re))
|
|
{
|
|
NERR(REG_ETOOBIG);
|
|
return;
|
|
}
|
|
|
|
if (s->tmp != NULL)
|
|
return; /* already done */
|
|
|
|
s->tmp = s;
|
|
for (a = s->outs; a != NULL && !NISERR(); a = oa)
|
|
{
|
|
removetraverse(nfa, a->to);
|
|
if (NISERR())
|
|
break;
|
|
oa = a->outchain;
|
|
switch (a->type)
|
|
{
|
|
case PLAIN:
|
|
case EMPTY:
|
|
/* nothing to do */
|
|
break;
|
|
case AHEAD:
|
|
case BEHIND:
|
|
case '^':
|
|
case '$':
|
|
case LACON:
|
|
/* replace it */
|
|
newarc(nfa, EMPTY, 0, s, a->to);
|
|
freearc(nfa, a);
|
|
break;
|
|
default:
|
|
NERR(REG_ASSERT);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set
|
|
*/
|
|
static void
|
|
cleartraverse(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;
|
|
}
|
|
|
|
if (s->tmp == NULL)
|
|
return;
|
|
s->tmp = NULL;
|
|
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
cleartraverse(nfa, a->to);
|
|
}
|
|
|
|
/*
|
|
* single_color_transition - does getting from s1 to s2 cross one PLAIN arc?
|
|
*
|
|
* If traversing from s1 to s2 requires a single PLAIN match (possibly of any
|
|
* of a set of colors), return a state whose outarc list contains only PLAIN
|
|
* arcs of those color(s). Otherwise return NULL.
|
|
*
|
|
* This is used before optimizing the NFA, so there may be EMPTY arcs, which
|
|
* we should ignore; the possibility of an EMPTY is why the result state could
|
|
* be different from s1.
|
|
*
|
|
* It's worth troubling to handle multiple parallel PLAIN arcs here because a
|
|
* bracket construct such as [abc] might yield either one or several parallel
|
|
* PLAIN arcs depending on earlier atoms in the expression. We'd rather that
|
|
* that implementation detail not create user-visible performance differences.
|
|
*/
|
|
static struct state *
|
|
single_color_transition(struct state *s1, struct state *s2)
|
|
{
|
|
struct arc *a;
|
|
|
|
/* Ignore leading EMPTY arc, if any */
|
|
if (s1->nouts == 1 && s1->outs->type == EMPTY)
|
|
s1 = s1->outs->to;
|
|
/* Likewise for any trailing EMPTY arc */
|
|
if (s2->nins == 1 && s2->ins->type == EMPTY)
|
|
s2 = s2->ins->from;
|
|
/* Perhaps we could have a single-state loop in between, if so reject */
|
|
if (s1 == s2)
|
|
return NULL;
|
|
/* s1 must have at least one outarc... */
|
|
if (s1->outs == NULL)
|
|
return NULL;
|
|
/* ... and they must all be PLAIN arcs to s2 */
|
|
for (a = s1->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->type != PLAIN || a->to != s2)
|
|
return NULL;
|
|
}
|
|
/* OK, return s1 as the possessor of the relevant outarcs */
|
|
return s1;
|
|
}
|
|
|
|
/*
|
|
* specialcolors - fill in special colors for an NFA
|
|
*/
|
|
static void
|
|
specialcolors(struct nfa *nfa)
|
|
{
|
|
/* false colors for BOS, BOL, EOS, EOL */
|
|
if (nfa->parent == NULL)
|
|
{
|
|
nfa->bos[0] = pseudocolor(nfa->cm);
|
|
nfa->bos[1] = pseudocolor(nfa->cm);
|
|
nfa->eos[0] = pseudocolor(nfa->cm);
|
|
nfa->eos[1] = pseudocolor(nfa->cm);
|
|
}
|
|
else
|
|
{
|
|
assert(nfa->parent->bos[0] != COLORLESS);
|
|
nfa->bos[0] = nfa->parent->bos[0];
|
|
assert(nfa->parent->bos[1] != COLORLESS);
|
|
nfa->bos[1] = nfa->parent->bos[1];
|
|
assert(nfa->parent->eos[0] != COLORLESS);
|
|
nfa->eos[0] = nfa->parent->eos[0];
|
|
assert(nfa->parent->eos[1] != COLORLESS);
|
|
nfa->eos[1] = nfa->parent->eos[1];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* optimize - optimize an NFA
|
|
*
|
|
* 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 */
|
|
{
|
|
#ifdef REG_DEBUG
|
|
int verbose = (f != NULL) ? 1 : 0;
|
|
|
|
if (verbose)
|
|
fprintf(f, "\ninitial cleanup:\n");
|
|
#endif
|
|
cleanup(nfa); /* may simplify situation */
|
|
#ifdef REG_DEBUG
|
|
if (verbose)
|
|
dumpnfa(nfa, f);
|
|
if (verbose)
|
|
fprintf(f, "\nempties:\n");
|
|
#endif
|
|
fixempties(nfa, f); /* get rid of EMPTY arcs */
|
|
#ifdef REG_DEBUG
|
|
if (verbose)
|
|
fprintf(f, "\nconstraints:\n");
|
|
#endif
|
|
fixconstraintloops(nfa, f); /* get rid of constraint loops */
|
|
pullback(nfa, f); /* pull back constraints backward */
|
|
pushfwd(nfa, f); /* push fwd constraints forward */
|
|
#ifdef REG_DEBUG
|
|
if (verbose)
|
|
fprintf(f, "\nfinal cleanup:\n");
|
|
#endif
|
|
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 *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;
|
|
}
|
|
/* 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 *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(nfa, 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;
|
|
case REPLACEARC: /* replace arc's color */
|
|
newarc(nfa, a->type, con->co, a->from, 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 *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 *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(nfa, 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;
|
|
case REPLACEARC: /* replace arc's color */
|
|
newarc(nfa, a->type, con->co, from, a->to);
|
|
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
|
|
* #def REPLACEARC 4 // replace arc's color with constraint color
|
|
*/
|
|
static int
|
|
combine(struct nfa *nfa,
|
|
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;
|
|
if (con->co == RAINBOW)
|
|
{
|
|
/* con is satisfied unless arc's color is a pseudocolor */
|
|
if (!(nfa->cm->cd[a->co].flags & PSEUDO))
|
|
return SATISFIED;
|
|
}
|
|
else if (a->co == RAINBOW)
|
|
{
|
|
/* con is incompatible if it's for a pseudocolor */
|
|
if (nfa->cm->cd[con->co].flags & PSEUDO)
|
|
return INCOMPATIBLE;
|
|
/* otherwise, constraint constrains arc to be only its color */
|
|
return REPLACEARC;
|
|
}
|
|
return INCOMPATIBLE;
|
|
break;
|
|
case CA('^', '^'): /* collision, similar constraints */
|
|
case CA('$', '$'):
|
|
if (con->co == a->co) /* true duplication */
|
|
return SATISFIED;
|
|
return INCOMPATIBLE;
|
|
break;
|
|
case CA(AHEAD, AHEAD): /* collision, similar constraints */
|
|
case CA(BEHIND, BEHIND):
|
|
if (con->co == a->co) /* true duplication */
|
|
return SATISFIED;
|
|
if (con->co == RAINBOW)
|
|
{
|
|
/* con is satisfied unless arc's color is a pseudocolor */
|
|
if (!(nfa->cm->cd[a->co].flags & PSEUDO))
|
|
return SATISFIED;
|
|
}
|
|
else if (a->co == RAINBOW)
|
|
{
|
|
/* con is incompatible if it's for a pseudocolor */
|
|
if (nfa->cm->cd[con->co].flags & PSEUDO)
|
|
return INCOMPATIBLE;
|
|
/* otherwise, constraint constrains arc to be only its color */
|
|
return REPLACEARC;
|
|
}
|
|
return INCOMPATIBLE;
|
|
break;
|
|
case CA('^', BEHIND): /* collision, dissimilar constraints */
|
|
case CA(BEHIND, '^'):
|
|
case CA('$', AHEAD):
|
|
case CA(AHEAD, '$'):
|
|
return INCOMPATIBLE;
|
|
break;
|
|
case CA('^', '$'): /* constraints passing each other */
|
|
case CA('^', AHEAD):
|
|
case CA(BEHIND, '$'):
|
|
case CA(BEHIND, AHEAD):
|
|
case CA('$', '^'):
|
|
case CA('$', BEHIND):
|
|
case CA(AHEAD, '^'):
|
|
case CA(AHEAD, BEHIND):
|
|
case CA('^', LACON):
|
|
case CA(BEHIND, LACON):
|
|
case CA('$', LACON):
|
|
case CA(AHEAD, LACON):
|
|
return COMPATIBLE;
|
|
break;
|
|
}
|
|
assert(NOTREACHED);
|
|
return INCOMPATIBLE; /* for benefit of blind compilers */
|
|
}
|
|
|
|
/*
|
|
* fixempties - get rid of EMPTY arcs
|
|
*/
|
|
static void
|
|
fixempties(struct nfa *nfa,
|
|
FILE *f) /* for debug output; NULL none */
|
|
{
|
|
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;
|
|
/* while we're at it, ensure tmp fields are clear for next step */
|
|
assert(s->tmp == NULL);
|
|
if (s->flag || s->nins != 1)
|
|
continue;
|
|
a = s->ins;
|
|
assert(a != NULL && a->inchain == NULL);
|
|
if (a->type != EMPTY)
|
|
continue;
|
|
if (s != a->from)
|
|
moveouts(nfa, s, a->from);
|
|
dropstate(nfa, s);
|
|
}
|
|
|
|
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;
|
|
|
|
/*
|
|
* Now remove all the EMPTY arcs, since we don't need them anymore.
|
|
*/
|
|
for (s = nfa->states; s != NULL; s = s->next)
|
|
{
|
|
for (a = s->outs; a != NULL; a = nexta)
|
|
{
|
|
nexta = a->outchain;
|
|
if (a->type == EMPTY)
|
|
freearc(nfa, a);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* And remove any states that have become useless. (This cleanup is not
|
|
* very thorough, and would be even less so if we tried to combine it with
|
|
* the previous step; but cleanup() will take care of anything we miss.)
|
|
*/
|
|
for (s = nfa->states; s != NULL; s = nexts)
|
|
{
|
|
nexts = s->next;
|
|
if ((s->nins == 0 || s->nouts == 0) && !s->flag)
|
|
dropstate(nfa, s);
|
|
}
|
|
|
|
if (f != NULL)
|
|
dumpnfa(nfa, f);
|
|
}
|
|
|
|
/*
|
|
* 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 ... but that could still be enough to cause trouble.
|
|
*/
|
|
static struct state *
|
|
emptyreachable(struct nfa *nfa,
|
|
struct state *s,
|
|
struct state *lastfound,
|
|
struct arc **inarcsorig)
|
|
{
|
|
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 lastfound;
|
|
}
|
|
|
|
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 ... but that could still be enough to cause trouble.
|
|
*/
|
|
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 *nfa)
|
|
{
|
|
struct state *s;
|
|
struct state *nexts;
|
|
int n;
|
|
|
|
if (NISERR())
|
|
return;
|
|
|
|
/* clear out unreachable or dead-end states */
|
|
/* use pre to mark reachable, then post to mark can-reach-post */
|
|
markreachable(nfa, nfa->pre, (struct state *) NULL, nfa->pre);
|
|
markcanreach(nfa, nfa->post, nfa->pre, nfa->post);
|
|
for (s = nfa->states; s != NULL && !NISERR(); s = nexts)
|
|
{
|
|
nexts = s->next;
|
|
if (s->tmp != nfa->post && !s->flag)
|
|
dropstate(nfa, s);
|
|
}
|
|
assert(NISERR() || nfa->post->nins == 0 || nfa->post->tmp == nfa->post);
|
|
cleartraverse(nfa, nfa->pre);
|
|
assert(NISERR() || nfa->post->nins == 0 || nfa->post->tmp == NULL);
|
|
/* the nins==0 (final unreachable) case will be caught later */
|
|
|
|
/* renumber surviving states */
|
|
n = 0;
|
|
for (s = nfa->states; s != NULL; s = s->next)
|
|
s->no = n++;
|
|
nfa->nstates = n;
|
|
}
|
|
|
|
/*
|
|
* markreachable - recursive marking of reachable states
|
|
*/
|
|
static void
|
|
markreachable(struct nfa *nfa,
|
|
struct state *s,
|
|
struct state *okay, /* consider only states with this mark */
|
|
struct state *mark) /* the value to mark with */
|
|
{
|
|
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 (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 *nfa,
|
|
struct state *s,
|
|
struct state *okay, /* consider only states with this mark */
|
|
struct state *mark) /* the value to mark with */
|
|
{
|
|
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 (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 /* re_info bits to be ORed in */
|
|
analyze(struct nfa *nfa)
|
|
{
|
|
struct arc *a;
|
|
struct arc *aa;
|
|
|
|
if (NISERR())
|
|
return 0;
|
|
|
|
/* Detect whether NFA can't match anything */
|
|
if (nfa->pre->outs == NULL)
|
|
return REG_UIMPOSSIBLE;
|
|
|
|
/* Detect whether NFA matches all strings (possibly with length bounds) */
|
|
checkmatchall(nfa);
|
|
|
|
/* Detect whether NFA can possibly match a zero-length string */
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* checkmatchall - does the NFA represent no more than a string length test?
|
|
*
|
|
* If so, set nfa->minmatchall and nfa->maxmatchall correctly (they are -1
|
|
* to begin with) and set the MATCHALL bit in nfa->flags.
|
|
*
|
|
* To succeed, we require all arcs to be PLAIN RAINBOW arcs, except for those
|
|
* for pseudocolors (i.e., BOS/BOL/EOS/EOL). We must be able to reach the
|
|
* post state via RAINBOW arcs, and if there are any loops in the graph, they
|
|
* must be loop-to-self arcs, ensuring that each loop iteration consumes
|
|
* exactly one character. (Longer loops are problematic because they create
|
|
* non-consecutive possible match lengths; we have no good way to represent
|
|
* that situation for lengths beyond the DUPINF limit.)
|
|
*
|
|
* Pseudocolor arcs complicate things a little. We know that they can only
|
|
* appear as pre-state outarcs (for BOS/BOL) or post-state inarcs (for
|
|
* EOS/EOL). There, they must exactly replicate the parallel RAINBOW arcs,
|
|
* e.g. if the pre state has one RAINBOW outarc to state 2, it must have BOS
|
|
* and BOL outarcs to state 2, and no others. Missing or extra pseudocolor
|
|
* arcs can occur, meaning that the NFA involves some constraint on the
|
|
* adjacent characters, which makes it not a matchall NFA.
|
|
*/
|
|
static void
|
|
checkmatchall(struct nfa *nfa)
|
|
{
|
|
bool **haspaths;
|
|
struct state *s;
|
|
int i;
|
|
|
|
/*
|
|
* If there are too many states, don't bother trying to detect matchall.
|
|
* This limit serves to bound the time and memory we could consume below.
|
|
* Note that even if the graph is all-RAINBOW, if there are significantly
|
|
* more than DUPINF states then it's likely that there are paths of length
|
|
* more than DUPINF, which would force us to fail anyhow. In practice,
|
|
* plausible ways of writing a matchall regex with maximum finite path
|
|
* length K tend not to have very many more than K states.
|
|
*/
|
|
if (nfa->nstates > DUPINF * 2)
|
|
return;
|
|
|
|
/*
|
|
* First, scan all the states to verify that only RAINBOW arcs appear,
|
|
* plus pseudocolor arcs adjacent to the pre and post states. This lets
|
|
* us quickly eliminate most cases that aren't matchall NFAs.
|
|
*/
|
|
for (s = nfa->states; s != NULL; s = s->next)
|
|
{
|
|
struct arc *a;
|
|
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->type != PLAIN)
|
|
return; /* any LACONs make it non-matchall */
|
|
if (a->co != RAINBOW)
|
|
{
|
|
if (nfa->cm->cd[a->co].flags & PSEUDO)
|
|
{
|
|
/*
|
|
* Pseudocolor arc: verify it's in a valid place (this
|
|
* seems quite unlikely to fail, but let's be sure).
|
|
*/
|
|
if (s == nfa->pre &&
|
|
(a->co == nfa->bos[0] || a->co == nfa->bos[1]))
|
|
/* okay BOS/BOL arc */ ;
|
|
else if (a->to == nfa->post &&
|
|
(a->co == nfa->eos[0] || a->co == nfa->eos[1]))
|
|
/* okay EOS/EOL arc */ ;
|
|
else
|
|
return; /* unexpected pseudocolor arc */
|
|
/* We'll check these arcs some more below. */
|
|
}
|
|
else
|
|
return; /* any other color makes it non-matchall */
|
|
}
|
|
}
|
|
/* Also, assert that the tmp fields are available for use. */
|
|
assert(s->tmp == NULL);
|
|
}
|
|
|
|
/*
|
|
* The next cheapest check we can make is to verify that the BOS/BOL
|
|
* outarcs of the pre state reach the same states as its RAINBOW outarcs.
|
|
* If they don't, the NFA expresses some constraints on the character
|
|
* before the matched string, making it non-matchall. Likewise, the
|
|
* EOS/EOL inarcs of the post state must match its RAINBOW inarcs.
|
|
*/
|
|
if (!check_out_colors_match(nfa->pre, RAINBOW, nfa->bos[0]) ||
|
|
!check_out_colors_match(nfa->pre, RAINBOW, nfa->bos[1]) ||
|
|
!check_in_colors_match(nfa->post, RAINBOW, nfa->eos[0]) ||
|
|
!check_in_colors_match(nfa->post, RAINBOW, nfa->eos[1]))
|
|
return;
|
|
|
|
/*
|
|
* Initialize an array of path-length arrays, in which
|
|
* checkmatchall_recurse will return per-state results. This lets us
|
|
* memo-ize the recursive search and avoid exponential time consumption.
|
|
*/
|
|
haspaths = (bool **) MALLOC(nfa->nstates * sizeof(bool *));
|
|
if (haspaths == NULL)
|
|
return; /* fail quietly */
|
|
memset(haspaths, 0, nfa->nstates * sizeof(bool *));
|
|
|
|
/*
|
|
* Recursively search the graph for all-RAINBOW paths to the "post" state,
|
|
* starting at the "pre" state, and computing the lengths of the paths.
|
|
* (Given the preceding checks, there should be at least one such path.
|
|
* However we could get back a false result anyway, in case there are
|
|
* multi-state loops, paths exceeding DUPINF+1 length, or non-algorithmic
|
|
* failures such as ENOMEM.)
|
|
*/
|
|
if (checkmatchall_recurse(nfa, nfa->pre, haspaths))
|
|
{
|
|
/* The useful result is the path length array for the pre state */
|
|
bool *haspath = haspaths[nfa->pre->no];
|
|
int minmatch,
|
|
maxmatch,
|
|
morematch;
|
|
|
|
assert(haspath != NULL);
|
|
|
|
/*
|
|
* haspath[] now represents the set of possible path lengths; but we
|
|
* want to reduce that to a min and max value, because it doesn't seem
|
|
* worth complicating regexec.c to deal with nonconsecutive possible
|
|
* match lengths. Find min and max of first run of lengths, then
|
|
* verify there are no nonconsecutive lengths.
|
|
*/
|
|
for (minmatch = 0; minmatch <= DUPINF + 1; minmatch++)
|
|
{
|
|
if (haspath[minmatch])
|
|
break;
|
|
}
|
|
assert(minmatch <= DUPINF + 1); /* else checkmatchall_recurse lied */
|
|
for (maxmatch = minmatch; maxmatch < DUPINF + 1; maxmatch++)
|
|
{
|
|
if (!haspath[maxmatch + 1])
|
|
break;
|
|
}
|
|
for (morematch = maxmatch + 1; morematch <= DUPINF + 1; morematch++)
|
|
{
|
|
if (haspath[morematch])
|
|
{
|
|
haspath = NULL; /* fail, there are nonconsecutive lengths */
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (haspath != NULL)
|
|
{
|
|
/*
|
|
* Success, so record the info. Here we have a fine point: the
|
|
* path length from the pre state includes the pre-to-initial
|
|
* transition, so it's one more than the actually matched string
|
|
* length. (We avoided counting the final-to-post transition
|
|
* within checkmatchall_recurse, but not this one.) This is why
|
|
* checkmatchall_recurse allows one more level of path length than
|
|
* might seem necessary. This decrement also takes care of
|
|
* converting checkmatchall_recurse's definition of "infinity" as
|
|
* "DUPINF+1" to our normal representation as "DUPINF".
|
|
*/
|
|
assert(minmatch > 0); /* else pre and post states were adjacent */
|
|
nfa->minmatchall = minmatch - 1;
|
|
nfa->maxmatchall = maxmatch - 1;
|
|
nfa->flags |= MATCHALL;
|
|
}
|
|
}
|
|
|
|
/* Clean up */
|
|
for (i = 0; i < nfa->nstates; i++)
|
|
{
|
|
if (haspaths[i] != NULL)
|
|
FREE(haspaths[i]);
|
|
}
|
|
FREE(haspaths);
|
|
}
|
|
|
|
/*
|
|
* checkmatchall_recurse - recursive search for checkmatchall
|
|
*
|
|
* s is the state to be examined in this recursion level.
|
|
* haspaths[] is an array of per-state exit path length arrays.
|
|
*
|
|
* We return true if the search was performed successfully, false if
|
|
* we had to fail because of multi-state loops or other internal reasons.
|
|
* (Because "dead" states that can't reach the post state have been
|
|
* eliminated, and we already verified that only RAINBOW and matching
|
|
* pseudocolor arcs exist, every state should have RAINBOW path(s) to
|
|
* the post state. Hence we take a false result from recursive calls
|
|
* as meaning that we'd better fail altogether, not just that that
|
|
* particular state can't reach the post state.)
|
|
*
|
|
* On success, we store a malloc'd result array in haspaths[s->no],
|
|
* showing the possible path lengths from s to the post state.
|
|
* Each state's haspath[] array is of length DUPINF+2. The entries from
|
|
* k = 0 to DUPINF are true if there is an all-RAINBOW path of length k
|
|
* from this state to the string end. haspath[DUPINF+1] is true if all
|
|
* path lengths >= DUPINF+1 are possible. (Situations that cannot be
|
|
* represented under these rules cause failure.)
|
|
*
|
|
* checkmatchall is responsible for eventually freeing the haspath[] arrays.
|
|
*/
|
|
static bool
|
|
checkmatchall_recurse(struct nfa *nfa, struct state *s, bool **haspaths)
|
|
{
|
|
bool result = false;
|
|
bool foundloop = false;
|
|
bool *haspath;
|
|
struct arc *a;
|
|
|
|
/*
|
|
* Since this is recursive, it could be driven to stack overflow. But we
|
|
* need not treat that as a hard failure; just deem the NFA non-matchall.
|
|
*/
|
|
if (STACK_TOO_DEEP(nfa->v->re))
|
|
return false;
|
|
|
|
/* In case the search takes a long time, check for cancel */
|
|
if (CANCEL_REQUESTED(nfa->v->re))
|
|
{
|
|
NERR(REG_CANCEL);
|
|
return false;
|
|
}
|
|
|
|
/* Create a haspath array for this state */
|
|
haspath = (bool *) MALLOC((DUPINF + 2) * sizeof(bool));
|
|
if (haspath == NULL)
|
|
return false; /* again, treat as non-matchall */
|
|
memset(haspath, 0, (DUPINF + 2) * sizeof(bool));
|
|
|
|
/* Mark this state as being visited */
|
|
assert(s->tmp == NULL);
|
|
s->tmp = s;
|
|
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->co != RAINBOW)
|
|
continue; /* ignore pseudocolor arcs */
|
|
if (a->to == nfa->post)
|
|
{
|
|
/* We found an all-RAINBOW path to the post state */
|
|
result = true;
|
|
|
|
/*
|
|
* Mark this state as being zero steps away from the string end
|
|
* (the transition to the post state isn't counted).
|
|
*/
|
|
haspath[0] = true;
|
|
}
|
|
else if (a->to == s)
|
|
{
|
|
/* We found a cycle of length 1, which we'll deal with below. */
|
|
foundloop = true;
|
|
}
|
|
else if (a->to->tmp != NULL)
|
|
{
|
|
/* It's busy, so we found a cycle of length > 1, so fail. */
|
|
result = false;
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
/* Consider paths forward through this to-state. */
|
|
bool *nexthaspath;
|
|
int i;
|
|
|
|
/* If to-state was not already visited, recurse */
|
|
if (haspaths[a->to->no] == NULL)
|
|
{
|
|
result = checkmatchall_recurse(nfa, a->to, haspaths);
|
|
/* Fail if any recursive path fails */
|
|
if (!result)
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
/* The previous visit must have found path(s) to the end */
|
|
result = true;
|
|
}
|
|
assert(a->to->tmp == NULL);
|
|
nexthaspath = haspaths[a->to->no];
|
|
assert(nexthaspath != NULL);
|
|
|
|
/*
|
|
* Now, for every path of length i from a->to to the string end,
|
|
* there is a path of length i + 1 from s to the string end.
|
|
*/
|
|
if (nexthaspath[DUPINF] != nexthaspath[DUPINF + 1])
|
|
{
|
|
/*
|
|
* a->to has a path of length exactly DUPINF, but not longer;
|
|
* or it has paths of all lengths > DUPINF but not one of
|
|
* exactly that length. In either case, we cannot represent
|
|
* the possible path lengths from s correctly, so fail.
|
|
*/
|
|
result = false;
|
|
break;
|
|
}
|
|
/* Merge knowledge of these path lengths into what we have */
|
|
for (i = 0; i < DUPINF; i++)
|
|
haspath[i + 1] |= nexthaspath[i];
|
|
/* Infinity + 1 is still infinity */
|
|
haspath[DUPINF + 1] |= nexthaspath[DUPINF + 1];
|
|
}
|
|
}
|
|
|
|
if (result && foundloop)
|
|
{
|
|
/*
|
|
* If there is a length-1 loop at this state, then find the shortest
|
|
* known path length to the end. The loop means that every larger
|
|
* path length is possible, too. (It doesn't matter whether any of
|
|
* the longer lengths were already known possible.)
|
|
*/
|
|
int i;
|
|
|
|
for (i = 0; i <= DUPINF; i++)
|
|
{
|
|
if (haspath[i])
|
|
break;
|
|
}
|
|
for (i++; i <= DUPINF + 1; i++)
|
|
haspath[i] = true;
|
|
}
|
|
|
|
/* Report out the completed path length map */
|
|
assert(s->no < nfa->nstates);
|
|
assert(haspaths[s->no] == NULL);
|
|
haspaths[s->no] = haspath;
|
|
|
|
/* Mark state no longer busy */
|
|
s->tmp = NULL;
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* check_out_colors_match - subroutine for checkmatchall
|
|
*
|
|
* Check whether the set of states reachable from s by arcs of color co1
|
|
* is equivalent to the set reachable by arcs of color co2.
|
|
* checkmatchall already verified that all of the NFA's arcs are PLAIN,
|
|
* so we need not examine arc types here.
|
|
*/
|
|
static bool
|
|
check_out_colors_match(struct state *s, color co1, color co2)
|
|
{
|
|
bool result = true;
|
|
struct arc *a;
|
|
|
|
/*
|
|
* To do this in linear time, we assume that the NFA contains no duplicate
|
|
* arcs. Run through the out-arcs, marking states reachable by arcs of
|
|
* color co1. Run through again, un-marking states reachable by arcs of
|
|
* color co2; if we see a not-marked state, we know this co2 arc is
|
|
* unmatched. Then run through again, checking for still-marked states,
|
|
* and in any case leaving all the tmp fields reset to NULL.
|
|
*/
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->co == co1)
|
|
{
|
|
assert(a->to->tmp == NULL);
|
|
a->to->tmp = a->to;
|
|
}
|
|
}
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->co == co2)
|
|
{
|
|
if (a->to->tmp != NULL)
|
|
a->to->tmp = NULL;
|
|
else
|
|
result = false; /* unmatched co2 arc */
|
|
}
|
|
}
|
|
for (a = s->outs; a != NULL; a = a->outchain)
|
|
{
|
|
if (a->co == co1)
|
|
{
|
|
if (a->to->tmp != NULL)
|
|
{
|
|
result = false; /* unmatched co1 arc */
|
|
a->to->tmp = NULL;
|
|
}
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* check_in_colors_match - subroutine for checkmatchall
|
|
*
|
|
* Check whether the set of states that can reach s by arcs of color co1
|
|
* is equivalent to the set that can reach s by arcs of color co2.
|
|
* checkmatchall already verified that all of the NFA's arcs are PLAIN,
|
|
* so we need not examine arc types here.
|
|
*/
|
|
static bool
|
|
check_in_colors_match(struct state *s, color co1, color co2)
|
|
{
|
|
bool result = true;
|
|
struct arc *a;
|
|
|
|
/*
|
|
* Identical algorithm to check_out_colors_match, except examine the
|
|
* from-states of s' inarcs.
|
|
*/
|
|
for (a = s->ins; a != NULL; a = a->inchain)
|
|
{
|
|
if (a->co == co1)
|
|
{
|
|
assert(a->from->tmp == NULL);
|
|
a->from->tmp = a->from;
|
|
}
|
|
}
|
|
for (a = s->ins; a != NULL; a = a->inchain)
|
|
{
|
|
if (a->co == co2)
|
|
{
|
|
if (a->from->tmp != NULL)
|
|
a->from->tmp = NULL;
|
|
else
|
|
result = false; /* unmatched co2 arc */
|
|
}
|
|
}
|
|
for (a = s->ins; a != NULL; a = a->inchain)
|
|
{
|
|
if (a->co == co1)
|
|
{
|
|
if (a->from->tmp != NULL)
|
|
{
|
|
result = false; /* unmatched co1 arc */
|
|
a->from->tmp = NULL;
|
|
}
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* compact - construct the compact representation of an NFA
|
|
*/
|
|
static void
|
|
compact(struct nfa *nfa,
|
|
struct cnfa *cnfa)
|
|
{
|
|
struct state *s;
|
|
struct arc *a;
|
|
size_t nstates;
|
|
size_t narcs;
|
|
struct carc *ca;
|
|
struct carc *first;
|
|
|
|
assert(!NISERR());
|
|
|
|
nstates = 0;
|
|
narcs = 0;
|
|
for (s = nfa->states; s != NULL; s = s->next)
|
|
{
|
|
nstates++;
|
|
narcs += 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 = nfa->flags;
|
|
cnfa->minmatchall = nfa->minmatchall;
|
|
cnfa->maxmatchall = nfa->maxmatchall;
|
|
|
|
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);
|
|
assert(a->co >= 0);
|
|
ca->co = (color) (cnfa->ncolors + a->co);
|
|
ca->to = a->to->no;
|
|
ca++;
|
|
cnfa->flags |= HASLACONS;
|
|
break;
|
|
default:
|
|
NERR(REG_ASSERT);
|
|
return;
|
|
}
|
|
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 *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 *cnfa)
|
|
{
|
|
assert(!NULLCNFA(*cnfa)); /* not empty already */
|
|
FREE(cnfa->stflags);
|
|
FREE(cnfa->states);
|
|
FREE(cnfa->arcs);
|
|
ZAPCNFA(*cnfa);
|
|
}
|
|
|
|
/*
|
|
* dumpnfa - dump an NFA in human-readable form
|
|
*/
|
|
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]);
|
|
if (nfa->flags & HASLACONS)
|
|
fprintf(f, ", haslacons");
|
|
if (nfa->flags & MATCHALL)
|
|
{
|
|
fprintf(f, ", minmatchall %d", nfa->minmatchall);
|
|
if (nfa->maxmatchall == DUPINF)
|
|
fprintf(f, ", maxmatchall inf");
|
|
else
|
|
fprintf(f, ", maxmatchall %d", nfa->maxmatchall);
|
|
}
|
|
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 */
|
|
|
|
/*
|
|
* dumpstate - dump an NFA state in human-readable form
|
|
*/
|
|
static void
|
|
dumpstate(struct state *s,
|
|
FILE *f)
|
|
{
|
|
struct arc *a;
|
|
|
|
fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "",
|
|
(s->flag) ? s->flag : '.');
|
|
if (s->prev != NULL && s->prev->next != s)
|
|
fprintf(f, "\tstate chain bad\n");
|
|
if (s->nouts == 0)
|
|
fprintf(f, "\tno out arcs\n");
|
|
else
|
|
dumparcs(s, f);
|
|
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);
|
|
}
|
|
fflush(f);
|
|
}
|
|
|
|
/*
|
|
* dumparcs - dump out-arcs in human-readable form
|
|
*/
|
|
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 *a,
|
|
struct state *s,
|
|
FILE *f)
|
|
{
|
|
struct arc *aa;
|
|
|
|
fprintf(f, "\t");
|
|
switch (a->type)
|
|
{
|
|
case PLAIN:
|
|
if (a->co == RAINBOW)
|
|
fprintf(f, "[*]");
|
|
else
|
|
fprintf(f, "[%ld]", (long) a->co);
|
|
break;
|
|
case AHEAD:
|
|
if (a->co == RAINBOW)
|
|
fprintf(f, ">*>");
|
|
else
|
|
fprintf(f, ">%ld>", (long) a->co);
|
|
break;
|
|
case BEHIND:
|
|
if (a->co == RAINBOW)
|
|
fprintf(f, "<*<");
|
|
else
|
|
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 (aa = a->from->outs; aa != NULL; aa = aa->outchain)
|
|
if (aa == a)
|
|
break; /* NOTE BREAK OUT */
|
|
if (aa == NULL)
|
|
fprintf(f, "?!?"); /* missing from out-chain */
|
|
fprintf(f, "->");
|
|
if (a->to == NULL)
|
|
{
|
|
fprintf(f, "NULL");
|
|
return;
|
|
}
|
|
fprintf(f, "%d", a->to->no);
|
|
for (aa = a->to->ins; aa != NULL; aa = aa->inchain)
|
|
if (aa == a)
|
|
break; /* NOTE BREAK OUT */
|
|
if (aa == NULL)
|
|
fprintf(f, "?!?"); /* missing from in-chain */
|
|
}
|
|
#endif /* REG_DEBUG */
|
|
|
|
/*
|
|
* dumpcnfa - dump a compacted NFA in human-readable form
|
|
*/
|
|
#ifdef REG_DEBUG
|
|
static void
|
|
dumpcnfa(struct cnfa *cnfa,
|
|
FILE *f)
|
|
{
|
|
int st;
|
|
|
|
fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post);
|
|
if (cnfa->bos[0] != COLORLESS)
|
|
fprintf(f, ", bos [%ld]", (long) cnfa->bos[0]);
|
|
if (cnfa->bos[1] != COLORLESS)
|
|
fprintf(f, ", bol [%ld]", (long) cnfa->bos[1]);
|
|
if (cnfa->eos[0] != COLORLESS)
|
|
fprintf(f, ", eos [%ld]", (long) cnfa->eos[0]);
|
|
if (cnfa->eos[1] != COLORLESS)
|
|
fprintf(f, ", eol [%ld]", (long) cnfa->eos[1]);
|
|
if (cnfa->flags & HASLACONS)
|
|
fprintf(f, ", haslacons");
|
|
if (cnfa->flags & MATCHALL)
|
|
{
|
|
fprintf(f, ", minmatchall %d", cnfa->minmatchall);
|
|
if (cnfa->maxmatchall == DUPINF)
|
|
fprintf(f, ", maxmatchall inf");
|
|
else
|
|
fprintf(f, ", maxmatchall %d", cnfa->maxmatchall);
|
|
}
|
|
fprintf(f, "\n");
|
|
for (st = 0; st < cnfa->nstates; st++)
|
|
dumpcstate(st, cnfa, f);
|
|
fflush(f);
|
|
}
|
|
#endif
|
|
|
|
#ifdef REG_DEBUG /* subordinates of dumpcnfa */
|
|
|
|
/*
|
|
* dumpcstate - dump a compacted-NFA state in human-readable form
|
|
*/
|
|
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 == RAINBOW)
|
|
fprintf(f, "\t[*]->%d", ca->to);
|
|
else 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 /* REG_DEBUG */
|