1334 lines
35 KiB
C
1334 lines
35 KiB
C
/*
|
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* re_*exec and friends - match REs
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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 of
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* 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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#include "regguts.h"
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/*
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* Lazy-DFA representation.
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*/
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struct arcp { /* "pointer" to an outarc */
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struct sset *ss;
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color co;
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};
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struct sset { /* state set */
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unsigned *states; /* pointer to bitvector */
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unsigned hash; /* hash of bitvector */
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#define HASH(bv, nw) (((nw) == 1) ? *(bv) : hash(bv, nw))
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#define HIT(h,bv,ss,nw) ((ss)->hash == (h) && ((nw) == 1 || \
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memcmp(VS(bv), VS((ss)->states), (nw)*sizeof(unsigned)) == 0))
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int flags;
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#define STARTER 01 /* the initial state set */
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#define POSTSTATE 02 /* includes the goal state */
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#define LOCKED 04 /* locked in cache */
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#define NOPROGRESS 010 /* zero-progress state set */
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struct arcp ins; /* chain of inarcs pointing here */
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chr *lastseen; /* last entered on arrival here */
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struct sset **outs; /* outarc vector indexed by color */
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struct arcp *inchain; /* chain-pointer vector for outarcs */
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};
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struct dfa {
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int nssets; /* size of cache */
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int nssused; /* how many entries occupied yet */
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int nstates; /* number of states */
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int ncolors; /* length of outarc and inchain vectors */
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int wordsper; /* length of state-set bitvectors */
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struct sset *ssets; /* state-set cache */
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unsigned *statesarea; /* bitvector storage */
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unsigned *work; /* pointer to work area within statesarea */
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struct sset **outsarea; /* outarc-vector storage */
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struct arcp *incarea; /* inchain storage */
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struct cnfa *cnfa;
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struct colormap *cm;
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chr *lastpost; /* location of last cache-flushed success */
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chr *lastnopr; /* location of last cache-flushed NOPROGRESS */
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struct sset *search; /* replacement-search-pointer memory */
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int cptsmalloced; /* were the areas individually malloced? */
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char *mallocarea; /* self, or malloced area, or NULL */
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};
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#define WORK 1 /* number of work bitvectors needed */
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/*
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* Setup for non-malloc allocation for small cases.
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*/
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#define FEWSTATES 20 /* must be less than UBITS */
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#define FEWCOLORS 15
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struct smalldfa {
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struct dfa dfa;
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struct sset ssets[FEWSTATES*2];
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unsigned statesarea[FEWSTATES*2 + WORK];
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struct sset *outsarea[FEWSTATES*2 * FEWCOLORS];
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struct arcp incarea[FEWSTATES*2 * FEWCOLORS];
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};
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#define DOMALLOC ((struct smalldfa *)NULL) /* force malloc */
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/*
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* Internal variables, bundled for easy passing around.
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*/
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struct vars {
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regex_t *re;
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struct guts *g;
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int eflags; /* copies of arguments */
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size_t nmatch;
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regmatch_t *pmatch;
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rm_detail_t *details;
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chr *start; /* start of string */
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chr *stop; /* just past end of string */
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int err; /* error code if any (0 none) */
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struct dfa **subdfas; /* per-subre DFAs */
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struct smalldfa dfa1;
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struct smalldfa dfa2;
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};
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#define VISERR(vv) ((vv)->err != 0) /* have we seen an error yet? */
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#define ISERR() VISERR(v)
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#define VERR(vv,e) ((vv)->err = ((vv)->err ? (vv)->err : (e)))
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#define ERR(e) VERR(v, e) /* record an error */
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#define NOERR() {if (ISERR()) return v->err;} /* if error seen, return it */
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#define OFF(p) ((p) - v->start)
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#define LOFF(p) ((long)OFF(p))
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/*
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* forward declarations
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*/
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/* =====^!^===== begin forwards =====^!^===== */
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/* automatically gathered by fwd; do not hand-edit */
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/* === regexec.c === */
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int exec(regex_t *, const chr *, size_t, rm_detail_t *, size_t, regmatch_t [], int);
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static struct dfa *getsubdfa(struct vars *, struct subre *);
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static int simpleFind(struct vars *const, struct cnfa *const, struct colormap *const);
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static int complicatedFind(struct vars *const, struct cnfa *const, struct colormap *const);
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static int complicatedFindLoop(struct vars *const, struct dfa *const, struct dfa *const, chr **const);
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static void zapallsubs(regmatch_t *const, const size_t);
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static void zaptreesubs(struct vars *const, struct subre *const);
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static void subset(struct vars *const, struct subre *const, chr *const, chr *const);
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static int cdissect(struct vars *, struct subre *, chr *, chr *);
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static int ccondissect(struct vars *, struct subre *, chr *, chr *);
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static int crevcondissect(struct vars *, struct subre *, chr *, chr *);
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static int cbrdissect(struct vars *, struct subre *, chr *, chr *);
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static int caltdissect(struct vars *, struct subre *, chr *, chr *);
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static int citerdissect(struct vars *, struct subre *, chr *, chr *);
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static int creviterdissect(struct vars *, struct subre *, chr *, chr *);
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/* === rege_dfa.c === */
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static chr *longest(struct vars *const, struct dfa *const, chr *const, chr *const, int *const);
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static chr *shortest(struct vars *const, struct dfa *const, chr *const, chr *const, chr *const, chr **const, int *const);
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static chr *lastCold(struct vars *const, struct dfa *const);
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static struct dfa *newDFA(struct vars *const, struct cnfa *const, struct colormap *const, struct smalldfa *);
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static void freeDFA(struct dfa *const);
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static unsigned hash(unsigned *const, const int);
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static struct sset *initialize(struct vars *const, struct dfa *const, chr *const);
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static struct sset *miss(struct vars *const, struct dfa *const, struct sset *const, const pcolor, chr *const, chr *const);
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static int checkLAConstraint(struct vars *const, struct cnfa *const, chr *const, const pcolor);
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static struct sset *getVacantSS(struct vars *const, struct dfa *const, chr *const, chr *const);
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static struct sset *pickNextSS(struct vars *const, struct dfa *const, chr *const, chr *const);
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/* automatically gathered by fwd; do not hand-edit */
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/* =====^!^===== end forwards =====^!^===== */
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/*
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- exec - match regular expression
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^ int exec(regex_t *, const chr *, size_t, rm_detail_t *,
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^ size_t, regmatch_t [], int);
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*/
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int
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exec(
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regex_t *re,
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const chr *string,
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size_t len,
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rm_detail_t *details,
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size_t nmatch,
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regmatch_t pmatch[],
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int flags)
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{
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AllocVars(v);
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int st, backref;
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size_t n;
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size_t i;
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#define LOCALMAT 20
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regmatch_t mat[LOCALMAT];
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#define LOCALDFAS 40
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struct dfa *subdfas[LOCALDFAS];
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/*
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* Sanity checks.
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*/
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if (re == NULL || string == NULL || re->re_magic != REMAGIC) {
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FreeVars(v);
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return REG_INVARG;
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}
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if (re->re_csize != sizeof(chr)) {
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FreeVars(v);
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return REG_MIXED;
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}
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/*
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* Setup.
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*/
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v->re = re;
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v->g = (struct guts *)re->re_guts;
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if ((v->g->cflags®_EXPECT) && details == NULL) {
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FreeVars(v);
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return REG_INVARG;
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}
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if (v->g->info®_UIMPOSSIBLE) {
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FreeVars(v);
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return REG_NOMATCH;
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}
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backref = (v->g->info®_UBACKREF) ? 1 : 0;
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v->eflags = flags;
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if (v->g->cflags®_NOSUB) {
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nmatch = 0; /* override client */
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}
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v->nmatch = nmatch;
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if (backref) {
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/*
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* Need work area.
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*/
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if (v->g->nsub + 1 <= LOCALMAT) {
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v->pmatch = mat;
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} else {
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v->pmatch = (regmatch_t *)
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MALLOC((v->g->nsub + 1) * sizeof(regmatch_t));
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}
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if (v->pmatch == NULL) {
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FreeVars(v);
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return REG_ESPACE;
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}
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v->nmatch = v->g->nsub + 1;
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} else {
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v->pmatch = pmatch;
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}
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v->details = details;
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v->start = (chr *)string;
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v->stop = (chr *)string + len;
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v->err = 0;
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assert(v->g->ntree >= 0);
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n = (size_t) v->g->ntree;
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if (n <= LOCALDFAS)
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v->subdfas = subdfas;
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else
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v->subdfas = (struct dfa **) MALLOC(n * sizeof(struct dfa *));
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if (v->subdfas == NULL) {
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if (v->pmatch != pmatch && v->pmatch != mat)
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FREE(v->pmatch);
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FreeVars(v);
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return REG_ESPACE;
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}
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for (i = 0; i < n; i++)
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v->subdfas[i] = NULL;
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/*
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* Do it.
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*/
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assert(v->g->tree != NULL);
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if (backref) {
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st = complicatedFind(v, &v->g->tree->cnfa, &v->g->cmap);
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} else {
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st = simpleFind(v, &v->g->tree->cnfa, &v->g->cmap);
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}
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/*
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* Copy (portion of) match vector over if necessary.
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*/
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if (st == REG_OKAY && v->pmatch != pmatch && nmatch > 0) {
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zapallsubs(pmatch, nmatch);
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n = (nmatch < v->nmatch) ? nmatch : v->nmatch;
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memcpy(VS(pmatch), VS(v->pmatch), n*sizeof(regmatch_t));
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}
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/*
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* Clean up.
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*/
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if (v->pmatch != pmatch && v->pmatch != mat) {
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FREE(v->pmatch);
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}
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n = (size_t) v->g->ntree;
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for (i = 0; i < n; i++) {
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if (v->subdfas[i] != NULL)
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freeDFA(v->subdfas[i]);
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}
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if (v->subdfas != subdfas)
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FREE(v->subdfas);
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FreeVars(v);
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return st;
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}
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/*
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- getsubdfa - create or re-fetch the DFA for a subre node
|
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* We only need to create the DFA once per overall regex execution.
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* The DFA will be freed by the cleanup step in exec().
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*/
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static struct dfa *
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getsubdfa(struct vars * v,
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struct subre * t)
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{
|
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if (v->subdfas[t->id] == NULL) {
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v->subdfas[t->id] = newDFA(v, &t->cnfa, &v->g->cmap, DOMALLOC);
|
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if (ISERR())
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return NULL;
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}
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return v->subdfas[t->id];
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}
|
||
|
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/*
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- simpleFind - find a match for the main NFA (no-complications case)
|
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^ static int simpleFind(struct vars *, struct cnfa *, struct colormap *);
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*/
|
||
static int
|
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simpleFind(
|
||
struct vars *const v,
|
||
struct cnfa *const cnfa,
|
||
struct colormap *const cm)
|
||
{
|
||
struct dfa *s, *d;
|
||
chr *begin, *end = NULL;
|
||
chr *cold;
|
||
chr *open, *close; /* Open and close of range of possible
|
||
* starts */
|
||
int hitend;
|
||
int shorter = (v->g->tree->flags&SHORTER) ? 1 : 0;
|
||
|
||
/*
|
||
* First, a shot with the search RE.
|
||
*/
|
||
|
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s = newDFA(v, &v->g->search, cm, &v->dfa1);
|
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assert(!(ISERR() && s != NULL));
|
||
NOERR();
|
||
MDEBUG(("\nsearch at %ld\n", LOFF(v->start)));
|
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cold = NULL;
|
||
close = shortest(v, s, v->start, v->start, v->stop, &cold, NULL);
|
||
freeDFA(s);
|
||
NOERR();
|
||
if (v->g->cflags®_EXPECT) {
|
||
assert(v->details != NULL);
|
||
if (cold != NULL) {
|
||
v->details->rm_extend.rm_so = OFF(cold);
|
||
} else {
|
||
v->details->rm_extend.rm_so = OFF(v->stop);
|
||
}
|
||
v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
|
||
}
|
||
if (close == NULL) { /* not found */
|
||
return REG_NOMATCH;
|
||
}
|
||
if (v->nmatch == 0) { /* found, don't need exact location */
|
||
return REG_OKAY;
|
||
}
|
||
|
||
/*
|
||
* Find starting point and match.
|
||
*/
|
||
|
||
assert(cold != NULL);
|
||
open = cold;
|
||
cold = NULL;
|
||
MDEBUG(("between %ld and %ld\n", LOFF(open), LOFF(close)));
|
||
d = newDFA(v, cnfa, cm, &v->dfa1);
|
||
assert(!(ISERR() && d != NULL));
|
||
NOERR();
|
||
for (begin = open; begin <= close; begin++) {
|
||
MDEBUG(("\nfind trying at %ld\n", LOFF(begin)));
|
||
if (shorter) {
|
||
end = shortest(v, d, begin, begin, v->stop, NULL, &hitend);
|
||
} else {
|
||
end = longest(v, d, begin, v->stop, &hitend);
|
||
}
|
||
if (ISERR()) {
|
||
freeDFA(d);
|
||
return v->err;
|
||
}
|
||
if (hitend && cold == NULL) {
|
||
cold = begin;
|
||
}
|
||
if (end != NULL) {
|
||
break; /* NOTE BREAK OUT */
|
||
}
|
||
}
|
||
assert(end != NULL); /* search RE succeeded so loop should */
|
||
freeDFA(d);
|
||
|
||
/*
|
||
* And pin down details.
|
||
*/
|
||
|
||
assert(v->nmatch > 0);
|
||
v->pmatch[0].rm_so = OFF(begin);
|
||
v->pmatch[0].rm_eo = OFF(end);
|
||
if (v->g->cflags®_EXPECT) {
|
||
if (cold != NULL) {
|
||
v->details->rm_extend.rm_so = OFF(cold);
|
||
} else {
|
||
v->details->rm_extend.rm_so = OFF(v->stop);
|
||
}
|
||
v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
|
||
}
|
||
if (v->nmatch == 1) { /* no need for submatches */
|
||
return REG_OKAY;
|
||
}
|
||
|
||
/*
|
||
* Find submatches.
|
||
*/
|
||
|
||
zapallsubs(v->pmatch, v->nmatch);
|
||
return cdissect(v, v->g->tree, begin, end);
|
||
}
|
||
|
||
/*
|
||
- complicatedFind - find a match for the main NFA (with complications)
|
||
^ static int complicatedFind(struct vars *, struct cnfa *, struct colormap *);
|
||
*/
|
||
static int
|
||
complicatedFind(
|
||
struct vars *const v,
|
||
struct cnfa *const cnfa,
|
||
struct colormap *const cm)
|
||
{
|
||
struct dfa *s, *d;
|
||
chr *cold = NULL; /* silence gcc 4 warning */
|
||
int ret;
|
||
|
||
s = newDFA(v, &v->g->search, cm, &v->dfa1);
|
||
NOERR();
|
||
d = newDFA(v, cnfa, cm, &v->dfa2);
|
||
if (ISERR()) {
|
||
assert(d == NULL);
|
||
freeDFA(s);
|
||
return v->err;
|
||
}
|
||
|
||
ret = complicatedFindLoop(v, d, s, &cold);
|
||
|
||
freeDFA(d);
|
||
freeDFA(s);
|
||
NOERR();
|
||
if (v->g->cflags®_EXPECT) {
|
||
assert(v->details != NULL);
|
||
if (cold != NULL) {
|
||
v->details->rm_extend.rm_so = OFF(cold);
|
||
} else {
|
||
v->details->rm_extend.rm_so = OFF(v->stop);
|
||
}
|
||
v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
|
||
}
|
||
return ret;
|
||
}
|
||
|
||
/*
|
||
- complicatedFindLoop - the heart of complicatedFind
|
||
^ static int complicatedFindLoop(struct vars *,
|
||
^ struct dfa *, struct dfa *, chr **);
|
||
*/
|
||
static int
|
||
complicatedFindLoop(
|
||
struct vars *const v,
|
||
struct dfa *const d,
|
||
struct dfa *const s,
|
||
chr **const coldp) /* where to put coldstart pointer */
|
||
{
|
||
chr *begin, *end;
|
||
chr *cold;
|
||
chr *open, *close; /* Open and close of range of possible
|
||
* starts */
|
||
chr *estart, *estop;
|
||
int er, hitend;
|
||
int shorter = v->g->tree->flags&SHORTER;
|
||
|
||
assert(d != NULL && s != NULL);
|
||
cold = NULL;
|
||
close = v->start;
|
||
do {
|
||
MDEBUG(("\ncsearch at %ld\n", LOFF(close)));
|
||
close = shortest(v, s, close, close, v->stop, &cold, NULL);
|
||
if (close == NULL) {
|
||
break; /* NOTE BREAK */
|
||
}
|
||
assert(cold != NULL);
|
||
open = cold;
|
||
cold = NULL;
|
||
MDEBUG(("cbetween %ld and %ld\n", LOFF(open), LOFF(close)));
|
||
for (begin = open; begin <= close; begin++) {
|
||
MDEBUG(("\ncomplicatedFind trying at %ld\n", LOFF(begin)));
|
||
estart = begin;
|
||
estop = v->stop;
|
||
for (;;) {
|
||
if (shorter) {
|
||
end = shortest(v, d, begin, estart, estop, NULL, &hitend);
|
||
} else {
|
||
end = longest(v, d, begin, estop, &hitend);
|
||
}
|
||
if (hitend && cold == NULL) {
|
||
cold = begin;
|
||
}
|
||
if (end == NULL) {
|
||
break; /* NOTE BREAK OUT */
|
||
}
|
||
|
||
MDEBUG(("tentative end %ld\n", LOFF(end)));
|
||
zapallsubs(v->pmatch, v->nmatch);
|
||
er = cdissect(v, v->g->tree, begin, end);
|
||
if (er == REG_OKAY) {
|
||
if (v->nmatch > 0) {
|
||
v->pmatch[0].rm_so = OFF(begin);
|
||
v->pmatch[0].rm_eo = OFF(end);
|
||
}
|
||
*coldp = cold;
|
||
return REG_OKAY;
|
||
}
|
||
if (er != REG_NOMATCH) {
|
||
ERR(er);
|
||
*coldp = cold;
|
||
return er;
|
||
}
|
||
if ((shorter) ? end == estop : end == begin) {
|
||
break;
|
||
}
|
||
|
||
/*
|
||
* Go around and try again
|
||
*/
|
||
|
||
if (shorter) {
|
||
estart = end + 1;
|
||
} else {
|
||
estop = end - 1;
|
||
}
|
||
}
|
||
}
|
||
} while (close < v->stop);
|
||
|
||
*coldp = cold;
|
||
return REG_NOMATCH;
|
||
}
|
||
|
||
/*
|
||
- zapallsubs - initialize all subexpression matches to "no match"
|
||
^ static void zapallsubs(regmatch_t *, size_t);
|
||
*/
|
||
static void
|
||
zapallsubs(
|
||
regmatch_t *const p,
|
||
const size_t n)
|
||
{
|
||
size_t i;
|
||
|
||
for (i = n-1; i > 0; i--) {
|
||
p[i].rm_so = -1;
|
||
p[i].rm_eo = -1;
|
||
}
|
||
}
|
||
|
||
/*
|
||
- zaptreesubs - initialize subexpressions within subtree to "no match"
|
||
^ static void zaptreesubs(struct vars *, struct subre *);
|
||
*/
|
||
static void
|
||
zaptreesubs(
|
||
struct vars *const v,
|
||
struct subre *const t)
|
||
{
|
||
if (t->op == '(') {
|
||
int n = t->subno;
|
||
assert(n > 0);
|
||
if ((size_t) n < v->nmatch) {
|
||
v->pmatch[n].rm_so = -1;
|
||
v->pmatch[n].rm_eo = -1;
|
||
}
|
||
}
|
||
|
||
if (t->left != NULL) {
|
||
zaptreesubs(v, t->left);
|
||
}
|
||
if (t->right != NULL) {
|
||
zaptreesubs(v, t->right);
|
||
}
|
||
}
|
||
|
||
/*
|
||
- subset - set subexpression match data for a successful subre
|
||
^ static void subset(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static void
|
||
subset(
|
||
struct vars *const v,
|
||
struct subre *const sub,
|
||
chr *const begin,
|
||
chr *const end)
|
||
{
|
||
int n = sub->subno;
|
||
|
||
assert(n > 0);
|
||
if ((size_t)n >= v->nmatch) {
|
||
return;
|
||
}
|
||
|
||
MDEBUG(("setting %d\n", n));
|
||
v->pmatch[n].rm_so = OFF(begin);
|
||
v->pmatch[n].rm_eo = OFF(end);
|
||
}
|
||
|
||
/*
|
||
- cdissect - check backrefs and determine subexpression matches
|
||
* cdissect recursively processes a subre tree to check matching of backrefs
|
||
* and/or identify submatch boundaries for capture nodes. The proposed match
|
||
* runs from "begin" to "end" (not including "end"), and we are basically
|
||
* "dissecting" it to see where the submatches are.
|
||
* Before calling any level of cdissect, the caller must have run the node's
|
||
* DFA and found that the proposed substring satisfies the DFA. (We make
|
||
* the caller do that because in concatenation and iteration nodes, it's
|
||
* much faster to check all the substrings against the child DFAs before we
|
||
* recurse.) Also, caller must have cleared subexpression match data via
|
||
* zaptreesubs (or zapallsubs at the top level).
|
||
^ static int cdissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
cdissect(
|
||
struct vars *v,
|
||
struct subre *t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
int er;
|
||
|
||
assert(t != NULL);
|
||
MDEBUG(("cdissect %ld-%ld %c\n", LOFF(begin), LOFF(end), t->op));
|
||
|
||
switch (t->op) {
|
||
case '=': /* terminal node */
|
||
assert(t->left == NULL && t->right == NULL);
|
||
er = REG_OKAY; /* no action, parent did the work */
|
||
break;
|
||
case 'b': /* back reference */
|
||
assert(t->left == NULL && t->right == NULL);
|
||
er = cbrdissect(v, t, begin, end);
|
||
break;
|
||
case '.': /* concatenation */
|
||
assert(t->left != NULL && t->right != NULL);
|
||
if (t->left->flags & SHORTER) /* reverse scan */
|
||
er = crevcondissect(v, t, begin, end);
|
||
else
|
||
er = ccondissect(v, t, begin, end);
|
||
break;
|
||
case '|': /* alternation */
|
||
assert(t->left != NULL);
|
||
er = caltdissect(v, t, begin, end);
|
||
break;
|
||
case '*': /* iteration */
|
||
assert(t->left != NULL);
|
||
if (t->left->flags & SHORTER) /* reverse scan */
|
||
er = creviterdissect(v, t, begin, end);
|
||
else
|
||
er = citerdissect(v, t, begin, end);
|
||
break;
|
||
case '(': /* capturing */
|
||
assert(t->left != NULL && t->right == NULL);
|
||
assert(t->subno > 0);
|
||
er = cdissect(v, t->left, begin, end);
|
||
if (er == REG_OKAY) {
|
||
subset(v, t, begin, end);
|
||
}
|
||
break;
|
||
default:
|
||
er = REG_ASSERT;
|
||
break;
|
||
}
|
||
|
||
/*
|
||
* We should never have a match failure unless backrefs lurk below;
|
||
* otherwise, either caller failed to check the DFA, or there's some
|
||
* inconsistency between the DFA and the node's innards.
|
||
*/
|
||
assert(er != REG_NOMATCH || (t->flags & BACKR));
|
||
|
||
return er;
|
||
}
|
||
|
||
/*
|
||
- ccondissect - dissect match for concatenation node
|
||
^ static int ccondissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
ccondissect(
|
||
struct vars *v,
|
||
struct subre *t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
struct dfa *d, *d2;
|
||
chr *mid;
|
||
|
||
assert(t->op == '.');
|
||
assert(t->left != NULL && t->left->cnfa.nstates > 0);
|
||
assert(t->right != NULL && t->right->cnfa.nstates > 0);
|
||
assert(!(t->left->flags & SHORTER));
|
||
|
||
d = getsubdfa(v, t->left);
|
||
NOERR();
|
||
d2 = getsubdfa(v, t->right);
|
||
NOERR();
|
||
|
||
MDEBUG(("cConcat %d\n", t->id));
|
||
|
||
/*
|
||
* Pick a tentative midpoint.
|
||
*/
|
||
mid = longest(v, d, begin, end, (int *) NULL);
|
||
if (mid == NULL) {
|
||
return REG_NOMATCH;
|
||
}
|
||
MDEBUG(("tentative midpoint %ld\n", LOFF(mid)));
|
||
|
||
/*
|
||
* Iterate until satisfaction or failure.
|
||
*/
|
||
|
||
for (;;) {
|
||
/*
|
||
* Try this midpoint on for size.
|
||
*/
|
||
|
||
if (longest(v, d2, mid, end, NULL) == end) {
|
||
int er = cdissect(v, t->left, begin, mid);
|
||
|
||
if (er == REG_OKAY) {
|
||
er = cdissect(v, t->right, mid, end);
|
||
if (er == REG_OKAY) {
|
||
/*
|
||
* Satisfaction.
|
||
*/
|
||
|
||
MDEBUG(("successful\n"));
|
||
return REG_OKAY;
|
||
}
|
||
}
|
||
if (er != REG_NOMATCH) {
|
||
return er;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* That midpoint didn't work, find a new one.
|
||
*/
|
||
|
||
if (mid == begin) {
|
||
/*
|
||
* All possibilities exhausted.
|
||
*/
|
||
|
||
MDEBUG(("%d no midpoint\n", t->id));
|
||
return REG_NOMATCH;
|
||
}
|
||
mid = longest(v, d, begin, mid-1, NULL);
|
||
if (mid == NULL) {
|
||
/*
|
||
* Failed to find a new one.
|
||
*/
|
||
|
||
MDEBUG(("%d failed midpoint\n", t->id));
|
||
return REG_NOMATCH;
|
||
}
|
||
MDEBUG(("%d: new midpoint %ld\n", t->id, LOFF(mid)));
|
||
zaptreesubs(v, t->left);
|
||
zaptreesubs(v, t->right);
|
||
}
|
||
}
|
||
|
||
/*
|
||
- crevcondissect - dissect match for concatenation node, shortest-first
|
||
^ static int crevcondissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
crevcondissect(
|
||
struct vars *v,
|
||
struct subre *t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
struct dfa *d, *d2;
|
||
chr *mid;
|
||
|
||
assert(t->op == '.');
|
||
assert(t->left != NULL && t->left->cnfa.nstates > 0);
|
||
assert(t->right != NULL && t->right->cnfa.nstates > 0);
|
||
assert(t->left->flags&SHORTER);
|
||
|
||
d = getsubdfa(v, t->left);
|
||
NOERR();
|
||
d2 = getsubdfa(v, t->right);
|
||
NOERR();
|
||
|
||
MDEBUG(("crevcon %d\n", t->id));
|
||
|
||
/*
|
||
* Pick a tentative midpoint.
|
||
*/
|
||
|
||
mid = shortest(v, d, begin, begin, end, (chr **) NULL, (int *) NULL);
|
||
if (mid == NULL) {
|
||
return REG_NOMATCH;
|
||
}
|
||
MDEBUG(("tentative midpoint %ld\n", LOFF(mid)));
|
||
|
||
/*
|
||
* Iterate until satisfaction or failure.
|
||
*/
|
||
|
||
for (;;) {
|
||
/*
|
||
* Try this midpoint on for size.
|
||
*/
|
||
|
||
if (longest(v, d2, mid, end, NULL) == end) {
|
||
int er = cdissect(v, t->left, begin, mid);
|
||
|
||
if (er == REG_OKAY) {
|
||
er = cdissect(v, t->right, mid, end);
|
||
if (er == REG_OKAY) {
|
||
/*
|
||
* Satisfaction.
|
||
*/
|
||
|
||
MDEBUG(("successful\n"));
|
||
return REG_OKAY;
|
||
}
|
||
}
|
||
if (er != REG_NOMATCH) {
|
||
return er;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* That midpoint didn't work, find a new one.
|
||
*/
|
||
|
||
if (mid == end) {
|
||
/*
|
||
* All possibilities exhausted.
|
||
*/
|
||
|
||
MDEBUG(("%d no midpoint\n", t->id));
|
||
return REG_NOMATCH;
|
||
}
|
||
mid = shortest(v, d, begin, mid+1, end, NULL, NULL);
|
||
if (mid == NULL) {
|
||
/*
|
||
* Failed to find a new one.
|
||
*/
|
||
|
||
MDEBUG(("%d failed midpoint\n", t->id));
|
||
return REG_NOMATCH;
|
||
}
|
||
MDEBUG(("%d: new midpoint %ld\n", t->id, LOFF(mid)));
|
||
zaptreesubs(v, t->left);
|
||
zaptreesubs(v, t->right);
|
||
}
|
||
}
|
||
|
||
/*
|
||
- cbrdissect - dissect match for backref node
|
||
^ static int cbrdissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
cbrdissect(
|
||
struct vars *v,
|
||
struct subre *t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
int n = t->subno, min = t->min, max = t->max;
|
||
size_t numreps;
|
||
size_t tlen;
|
||
size_t brlen;
|
||
chr *brstring;
|
||
chr *p;
|
||
|
||
assert(t != NULL);
|
||
assert(t->op == 'b');
|
||
assert(n >= 0);
|
||
assert((size_t)n < v->nmatch);
|
||
|
||
MDEBUG(("cbackref n%d %d{%d-%d}\n", t->id, n, min, max));
|
||
|
||
/* get the backreferenced string */
|
||
if (v->pmatch[n].rm_so == -1) {
|
||
return REG_NOMATCH;
|
||
}
|
||
brstring = v->start + v->pmatch[n].rm_so;
|
||
brlen = v->pmatch[n].rm_eo - v->pmatch[n].rm_so;
|
||
|
||
/* special cases for zero-length strings */
|
||
if (brlen == 0) {
|
||
/*
|
||
* matches only if target is zero length, but any number of
|
||
* repetitions can be considered to be present
|
||
*/
|
||
if (begin == end && min <= max) {
|
||
MDEBUG(("cbackref matched trivially\n"));
|
||
return REG_OKAY;
|
||
}
|
||
return REG_NOMATCH;
|
||
}
|
||
if (begin == end) {
|
||
/* matches only if zero repetitions are okay */
|
||
if (min == 0) {
|
||
MDEBUG(("cbackref matched trivially\n"));
|
||
return REG_OKAY;
|
||
}
|
||
return REG_NOMATCH;
|
||
}
|
||
|
||
/*
|
||
* check target length to see if it could possibly be an allowed number of
|
||
* repetitions of brstring
|
||
*/
|
||
|
||
assert(end > begin);
|
||
tlen = end - begin;
|
||
if (tlen % brlen != 0)
|
||
return REG_NOMATCH;
|
||
numreps = tlen / brlen;
|
||
if (numreps < (size_t)min || (numreps > (size_t)max && max != DUPINF))
|
||
return REG_NOMATCH;
|
||
|
||
/* okay, compare the actual string contents */
|
||
p = begin;
|
||
while (numreps-- > 0) {
|
||
if ((*v->g->compare) (brstring, p, brlen) != 0)
|
||
return REG_NOMATCH;
|
||
p += brlen;
|
||
}
|
||
|
||
MDEBUG(("cbackref matched\n"));
|
||
return REG_OKAY;
|
||
}
|
||
|
||
/*
|
||
- caltdissect - dissect match for alternation node
|
||
^ static int caltdissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
caltdissect(
|
||
struct vars *v,
|
||
struct subre *t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
struct dfa *d;
|
||
int er;
|
||
|
||
/* We loop, rather than tail-recurse, to handle a chain of alternatives */
|
||
while (t != NULL) {
|
||
assert(t->op == '|');
|
||
assert(t->left != NULL && t->left->cnfa.nstates > 0);
|
||
|
||
MDEBUG(("calt n%d\n", t->id));
|
||
|
||
d = getsubdfa(v, t->left);
|
||
NOERR();
|
||
if (longest(v, d, begin, end, (int *) NULL) == end) {
|
||
MDEBUG(("calt matched\n"));
|
||
er = cdissect(v, t->left, begin, end);
|
||
if (er != REG_NOMATCH) {
|
||
return er;
|
||
}
|
||
}
|
||
|
||
t = t->right;
|
||
}
|
||
|
||
return REG_NOMATCH;
|
||
}
|
||
|
||
/*
|
||
- citerdissect - dissect match for iteration node
|
||
^ static int citerdissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
citerdissect(struct vars * v,
|
||
struct subre * t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
struct dfa *d;
|
||
chr **endpts;
|
||
chr *limit;
|
||
int min_matches;
|
||
size_t max_matches;
|
||
int nverified;
|
||
int k;
|
||
int i;
|
||
int er;
|
||
|
||
assert(t->op == '*');
|
||
assert(t->left != NULL && t->left->cnfa.nstates > 0);
|
||
assert(!(t->left->flags & SHORTER));
|
||
assert(begin <= end);
|
||
|
||
/*
|
||
* If zero matches are allowed, and target string is empty, just declare
|
||
* victory. OTOH, if target string isn't empty, zero matches can't work
|
||
* so we pretend the min is 1.
|
||
*/
|
||
min_matches = t->min;
|
||
if (min_matches <= 0) {
|
||
if (begin == end)
|
||
return REG_OKAY;
|
||
min_matches = 1;
|
||
}
|
||
|
||
/*
|
||
* We need workspace to track the endpoints of each sub-match. Normally
|
||
* we consider only nonzero-length sub-matches, so there can be at most
|
||
* end-begin of them. However, if min is larger than that, we will also
|
||
* consider zero-length sub-matches in order to find enough matches.
|
||
*
|
||
* For convenience, endpts[0] contains the "begin" pointer and we store
|
||
* sub-match endpoints in endpts[1..max_matches].
|
||
*/
|
||
max_matches = end - begin;
|
||
if (max_matches > (size_t)t->max && t->max != DUPINF)
|
||
max_matches = t->max;
|
||
if (max_matches < (size_t)min_matches)
|
||
max_matches = min_matches;
|
||
endpts = (chr **) MALLOC((max_matches + 1) * sizeof(chr *));
|
||
if (endpts == NULL)
|
||
return REG_ESPACE;
|
||
endpts[0] = begin;
|
||
|
||
d = getsubdfa(v, t->left);
|
||
if (ISERR()) {
|
||
FREE(endpts);
|
||
return v->err;
|
||
}
|
||
MDEBUG(("citer %d\n", t->id));
|
||
|
||
/*
|
||
* Our strategy is to first find a set of sub-match endpoints that are
|
||
* valid according to the child node's DFA, and then recursively dissect
|
||
* each sub-match to confirm validity. If any validity check fails,
|
||
* backtrack the last sub-match and try again. And, when we next try for
|
||
* a validity check, we need not recheck any successfully verified
|
||
* sub-matches that we didn't move the endpoints of. nverified remembers
|
||
* how many sub-matches are currently known okay.
|
||
*/
|
||
|
||
/* initialize to consider first sub-match */
|
||
nverified = 0;
|
||
k = 1;
|
||
limit = end;
|
||
|
||
/* iterate until satisfaction or failure */
|
||
while (k > 0) {
|
||
/* try to find an endpoint for the k'th sub-match */
|
||
endpts[k] = longest(v, d, endpts[k - 1], limit, (int *) NULL);
|
||
if (endpts[k] == NULL) {
|
||
/* no match possible, so see if we can shorten previous one */
|
||
k--;
|
||
goto backtrack;
|
||
}
|
||
MDEBUG(("%d: working endpoint %d: %ld\n",
|
||
t->id, k, LOFF(endpts[k])));
|
||
|
||
/* k'th sub-match can no longer be considered verified */
|
||
if (nverified >= k)
|
||
nverified = k - 1;
|
||
|
||
if (endpts[k] != end) {
|
||
/* haven't reached end yet, try another iteration if allowed */
|
||
if ((size_t)k >= max_matches) {
|
||
/* must try to shorten some previous match */
|
||
k--;
|
||
goto backtrack;
|
||
}
|
||
|
||
/* reject zero-length match unless necessary to achieve min */
|
||
if (endpts[k] == endpts[k - 1] &&
|
||
(k >= min_matches || min_matches - k < end - endpts[k]))
|
||
goto backtrack;
|
||
|
||
k++;
|
||
limit = end;
|
||
continue;
|
||
}
|
||
|
||
/*
|
||
* We've identified a way to divide the string into k sub-matches
|
||
* that works so far as the child DFA can tell. If k is an allowed
|
||
* number of matches, start the slow part: recurse to verify each
|
||
* sub-match. We always have k <= max_matches, needn't check that.
|
||
*/
|
||
if (k < min_matches)
|
||
goto backtrack;
|
||
|
||
MDEBUG(("%d: verifying %d..%d\n", t->id, nverified + 1, k));
|
||
|
||
for (i = nverified + 1; i <= k; i++) {
|
||
zaptreesubs(v, t->left);
|
||
er = cdissect(v, t->left, endpts[i - 1], endpts[i]);
|
||
if (er == REG_OKAY) {
|
||
nverified = i;
|
||
continue;
|
||
}
|
||
if (er == REG_NOMATCH)
|
||
break;
|
||
/* oops, something failed */
|
||
FREE(endpts);
|
||
return er;
|
||
}
|
||
|
||
if (i > k) {
|
||
/* satisfaction */
|
||
MDEBUG(("%d successful\n", t->id));
|
||
FREE(endpts);
|
||
return REG_OKAY;
|
||
}
|
||
|
||
/* match failed to verify, so backtrack */
|
||
|
||
backtrack:
|
||
/*
|
||
* Must consider shorter versions of the current sub-match. However,
|
||
* we'll only ask for a zero-length match if necessary.
|
||
*/
|
||
while (k > 0) {
|
||
chr *prev_end = endpts[k - 1];
|
||
|
||
if (endpts[k] > prev_end) {
|
||
limit = endpts[k] - 1;
|
||
if (limit > prev_end ||
|
||
(k < min_matches && min_matches - k >= end - prev_end)) {
|
||
/* break out of backtrack loop, continue the outer one */
|
||
break;
|
||
}
|
||
}
|
||
/* can't shorten k'th sub-match any more, consider previous one */
|
||
k--;
|
||
}
|
||
}
|
||
|
||
/* all possibilities exhausted */
|
||
MDEBUG(("%d failed\n", t->id));
|
||
FREE(endpts);
|
||
return REG_NOMATCH;
|
||
}
|
||
|
||
/*
|
||
- creviterdissect - dissect match for iteration node, shortest-first
|
||
^ static int creviterdissect(struct vars *, struct subre *, chr *, chr *);
|
||
*/
|
||
static int /* regexec return code */
|
||
creviterdissect(struct vars * v,
|
||
struct subre * t,
|
||
chr *begin, /* beginning of relevant substring */
|
||
chr *end) /* end of same */
|
||
{
|
||
struct dfa *d;
|
||
chr **endpts;
|
||
chr *limit;
|
||
int min_matches;
|
||
size_t max_matches;
|
||
int nverified;
|
||
int k;
|
||
int i;
|
||
int er;
|
||
|
||
assert(t->op == '*');
|
||
assert(t->left != NULL && t->left->cnfa.nstates > 0);
|
||
assert(t->left->flags & SHORTER);
|
||
assert(begin <= end);
|
||
|
||
/*
|
||
* If zero matches are allowed, and target string is empty, just declare
|
||
* victory. OTOH, if target string isn't empty, zero matches can't work
|
||
* so we pretend the min is 1.
|
||
*/
|
||
min_matches = t->min;
|
||
if (min_matches <= 0) {
|
||
if (begin == end)
|
||
return REG_OKAY;
|
||
min_matches = 1;
|
||
}
|
||
|
||
/*
|
||
* We need workspace to track the endpoints of each sub-match. Normally
|
||
* we consider only nonzero-length sub-matches, so there can be at most
|
||
* end-begin of them. However, if min is larger than that, we will also
|
||
* consider zero-length sub-matches in order to find enough matches.
|
||
*
|
||
* For convenience, endpts[0] contains the "begin" pointer and we store
|
||
* sub-match endpoints in endpts[1..max_matches].
|
||
*/
|
||
max_matches = end - begin;
|
||
if (max_matches > (size_t)t->max && t->max != DUPINF)
|
||
max_matches = t->max;
|
||
if (max_matches < (size_t)min_matches)
|
||
max_matches = min_matches;
|
||
endpts = (chr **) MALLOC((max_matches + 1) * sizeof(chr *));
|
||
if (endpts == NULL)
|
||
return REG_ESPACE;
|
||
endpts[0] = begin;
|
||
|
||
d = getsubdfa(v, t->left);
|
||
if (ISERR()) {
|
||
FREE(endpts);
|
||
return v->err;
|
||
}
|
||
MDEBUG(("creviter %d\n", t->id));
|
||
|
||
/*
|
||
* Our strategy is to first find a set of sub-match endpoints that are
|
||
* valid according to the child node's DFA, and then recursively dissect
|
||
* each sub-match to confirm validity. If any validity check fails,
|
||
* backtrack the last sub-match and try again. And, when we next try for
|
||
* a validity check, we need not recheck any successfully verified
|
||
* sub-matches that we didn't move the endpoints of. nverified remembers
|
||
* how many sub-matches are currently known okay.
|
||
*/
|
||
|
||
/* initialize to consider first sub-match */
|
||
nverified = 0;
|
||
k = 1;
|
||
limit = begin;
|
||
|
||
/* iterate until satisfaction or failure */
|
||
while (k > 0) {
|
||
/* disallow zero-length match unless necessary to achieve min */
|
||
if (limit == endpts[k - 1] &&
|
||
limit != end &&
|
||
(k >= min_matches || min_matches - k < end - limit))
|
||
limit++;
|
||
|
||
/* if this is the last allowed sub-match, it must reach to the end */
|
||
if ((size_t)k >= max_matches)
|
||
limit = end;
|
||
|
||
/* try to find an endpoint for the k'th sub-match */
|
||
endpts[k] = shortest(v, d, endpts[k - 1], limit, end,
|
||
(chr **) NULL, (int *) NULL);
|
||
if (endpts[k] == NULL) {
|
||
/* no match possible, so see if we can lengthen previous one */
|
||
k--;
|
||
goto backtrack;
|
||
}
|
||
MDEBUG(("%d: working endpoint %d: %ld\n",
|
||
t->id, k, LOFF(endpts[k])));
|
||
|
||
/* k'th sub-match can no longer be considered verified */
|
||
if (nverified >= k)
|
||
nverified = k - 1;
|
||
|
||
if (endpts[k] != end) {
|
||
/* haven't reached end yet, try another iteration if allowed */
|
||
if ((size_t)k >= max_matches) {
|
||
/* must try to lengthen some previous match */
|
||
k--;
|
||
goto backtrack;
|
||
}
|
||
|
||
k++;
|
||
limit = endpts[k - 1];
|
||
continue;
|
||
}
|
||
|
||
/*
|
||
* We've identified a way to divide the string into k sub-matches
|
||
* that works so far as the child DFA can tell. If k is an allowed
|
||
* number of matches, start the slow part: recurse to verify each
|
||
* sub-match. We always have k <= max_matches, needn't check that.
|
||
*/
|
||
if (k < min_matches)
|
||
goto backtrack;
|
||
|
||
MDEBUG(("%d: verifying %d..%d\n", t->id, nverified + 1, k));
|
||
|
||
for (i = nverified + 1; i <= k; i++) {
|
||
zaptreesubs(v, t->left);
|
||
er = cdissect(v, t->left, endpts[i - 1], endpts[i]);
|
||
if (er == REG_OKAY) {
|
||
nverified = i;
|
||
continue;
|
||
}
|
||
if (er == REG_NOMATCH)
|
||
break;
|
||
/* oops, something failed */
|
||
FREE(endpts);
|
||
return er;
|
||
}
|
||
|
||
if (i > k) {
|
||
/* satisfaction */
|
||
MDEBUG(("%d successful\n", t->id));
|
||
FREE(endpts);
|
||
return REG_OKAY;
|
||
}
|
||
|
||
/* match failed to verify, so backtrack */
|
||
|
||
backtrack:
|
||
/*
|
||
* Must consider longer versions of the current sub-match.
|
||
*/
|
||
while (k > 0) {
|
||
if (endpts[k] < end) {
|
||
limit = endpts[k] + 1;
|
||
/* break out of backtrack loop, continue the outer one */
|
||
break;
|
||
}
|
||
/* can't lengthen k'th sub-match any more, consider previous one */
|
||
k--;
|
||
}
|
||
}
|
||
|
||
/* all possibilities exhausted */
|
||
MDEBUG(("%d failed\n", t->id));
|
||
FREE(endpts);
|
||
return REG_NOMATCH;
|
||
}
|
||
|
||
#include "rege_dfa.c"
|
||
|
||
/*
|
||
* Local Variables:
|
||
* mode: c
|
||
* c-basic-offset: 4
|
||
* fill-column: 78
|
||
* End:
|
||
*/
|