1259 lines
40 KiB
C++
1259 lines
40 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
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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/common/backend/regex/regexec.cpp
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*
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*/
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#include "regex/regguts.h"
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/* lazy-DFA representation */
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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) \
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((ss)->hash == (h) && ((nw) == 1 || 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 master malloced area, or NULL */
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};
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#define WORK 1 /* number of work bitvectors needed */
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/* setup for non-malloc allocation for small cases */
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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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/* internal variables, bundled for easy passing around */
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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* search_start; /* search 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-tree-subre DFAs */
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struct dfa** ladfas; /* per-lacon-subre DFAs */
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struct sset** lblastcss; /* per-lacon-subre lookbehind restart data */
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chr** lblastcp; /* per-lacon-subre lookbehind restart data */
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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() \
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{ \
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if (ISERR()) \
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return v->err; \
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} /* 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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/* === regexec.c === */
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static struct dfa* getsubdfa(struct vars*, struct subre*);
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static struct dfa* getladfa(struct vars*, int);
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static int find(struct vars*, struct cnfa*, struct colormap*);
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static int cfind(struct vars*, struct cnfa*, struct colormap*);
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static int cfindloop(struct vars*, struct cnfa*, struct colormap*, struct dfa*, struct dfa*, chr**);
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static void zapallsubs(regmatch_t*, size_t);
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static void zaptreesubs(struct vars*, struct subre*);
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static void subset(struct vars*, struct subre*, chr*, chr*);
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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*, struct dfa*, chr*, chr*, int*);
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static chr* shortest(struct vars*, struct dfa*, chr*, chr*, chr*, chr**, int*);
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static int matchuntil(struct vars*, struct dfa*, chr*, struct sset**, chr**);
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static chr* lastcold(struct vars*, struct dfa*);
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static struct dfa* newdfa(struct vars*, struct cnfa*, struct colormap*, struct smalldfa*);
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static void freedfa(struct dfa*);
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static unsigned hash(unsigned*, int);
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static struct sset* initialize(struct vars*, struct dfa*, chr*);
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static struct sset* miss(struct vars*, struct dfa*, struct sset*, pcolor, chr*, chr*);
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static int lacon(struct vars*, struct cnfa*, chr*, pcolor);
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static struct sset* getvacant(struct vars*, struct dfa*, chr*, chr*);
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static struct sset* pickss(struct vars*, struct dfa*, chr*, chr*);
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/*
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* pg_regexec - match regular expression
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*/
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int pg_regexec(regex_t* re, const chr* string, size_t len, size_t search_start, rm_detail_t* details, size_t nmatch,
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regmatch_t pmatch[], int flags)
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{
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struct vars var;
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register struct vars* v = &var;
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int st;
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size_t n;
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size_t i;
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int backref;
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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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/* sanity checks */
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if (re == NULL || string == NULL || re->re_magic != REMAGIC)
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return REG_INVARG;
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if (re->re_csize != sizeof(chr))
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return REG_MIXED;
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if (search_start > len)
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return REG_NOMATCH;
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/* Initialize locale-dependent support */
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pg_set_regex_collation(re->re_collation);
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/* setup */
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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 & REG_EXPECT) && details == NULL)
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return REG_INVARG;
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if (v->g->info & REG_UIMPOSSIBLE)
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return REG_NOMATCH;
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backref = (v->g->info & REG_UBACKREF) ? 1 : 0;
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v->eflags = flags;
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if (v->g->cflags & REG_NOSUB)
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nmatch = 0; /* override client */
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v->nmatch = nmatch;
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if (backref) {
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/* need work area */
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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*)MALLOC((v->g->nsub + 1) * sizeof(regmatch_t));
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if (v->pmatch == NULL)
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return REG_ESPACE;
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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->search_start = (chr*)string + search_start;
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v->stop = (chr*)string + len;
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v->err = 0;
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v->subdfas = NULL;
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v->ladfas = NULL;
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v->lblastcss = NULL;
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v->lblastcp = NULL;
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/* below this point, "goto cleanup" will behave sanely */
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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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st = REG_ESPACE;
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goto cleanup;
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}
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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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Assert(v->g->nlacons >= 0);
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n = (size_t)v->g->nlacons;
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if (n > 0) {
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v->ladfas = (struct dfa**)MALLOC(n * sizeof(struct dfa*));
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if (v->ladfas == NULL) {
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st = REG_ESPACE;
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goto cleanup;
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}
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for (i = 0; i < n; i++)
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v->ladfas[i] = NULL;
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v->lblastcss = (struct sset**)MALLOC(n * sizeof(struct sset*));
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v->lblastcp = (chr**)MALLOC(n * sizeof(chr*));
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if (v->lblastcss == NULL || v->lblastcp == NULL) {
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st = REG_ESPACE;
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goto cleanup;
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}
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for (i = 0; i < n; i++) {
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v->lblastcss[i] = NULL;
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v->lblastcp[i] = NULL;
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}
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}
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/* do it */
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Assert(v->g->tree != NULL);
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if (backref)
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st = cfind(v, &v->g->tree->cnfa, &v->g->cmap);
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else
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st = find(v, &v->g->tree->cnfa, &v->g->cmap);
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/* copy (portion of) match vector over if necessary */
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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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errno_t ss_rc = memcpy_s(VS(pmatch), n * sizeof(regmatch_t), VS(v->pmatch), n * sizeof(regmatch_t));
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securec_check(ss_rc, "\0", "\0");
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}
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/* clean up */
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cleanup:
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if (v->pmatch != pmatch && v->pmatch != mat)
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FREE(v->pmatch);
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/* fix memory leak during regular expression execution */
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if (v->subdfas != NULL) {
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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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}
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if (v->ladfas != NULL) {
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n = (size_t)v->g->nlacons;
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for (i = 0; i < n; i++) {
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if (v->ladfas[i] != NULL)
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freedfa(v->ladfas[i]);
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}
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FREE(v->ladfas);
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}
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if (v->lblastcss != NULL)
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FREE(v->lblastcss);
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if (v->lblastcp != NULL)
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FREE(v->lblastcp);
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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 tree subre node
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*
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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 pg_regexec().
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*/
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static struct dfa* getsubdfa(struct vars* v, 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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* getladfa - create or re-fetch the DFA for a LACON subre node
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*
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* Same as above, but for LACONs.
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*/
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static struct dfa* getladfa(struct vars* v, int n)
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{
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Assert(n > 0 && n < v->g->nlacons && v->g->lacons != NULL);
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if (v->ladfas[n] == NULL) {
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struct subre* sub = &v->g->lacons[n];
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v->ladfas[n] = newdfa(v, &sub->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->ladfas[n];
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}
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/*
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* find - find a match for the main NFA (no-complications case)
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*/
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static int find(struct vars* v, struct cnfa* cnfa, struct colormap* cm)
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{
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struct dfa* s = NULL;
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struct dfa* d = NULL;
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chr* begin = NULL;
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chr* end = NULL;
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chr* cold = NULL;
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chr* open = NULL; /* open and close of range of possible starts */
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chr* close = NULL;
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int hitend;
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int shorter = (v->g->tree->flags & SHORTER) ? 1 : 0;
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/* 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));
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NOERR();
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MDEBUG(("\nsearch at %ld\n", LOFF(v->start)));
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cold = NULL;
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close = shortest(v, s, v->search_start, v->search_start, v->stop, &cold, (int*)NULL);
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freedfa(s);
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NOERR();
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if (v->g->cflags & REG_EXPECT) {
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Assert(v->details != NULL);
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if (cold != NULL)
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v->details->rm_extend.rm_so = OFF(cold);
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else
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v->details->rm_extend.rm_so = OFF(v->stop);
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v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
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}
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if (close == NULL) /* not found */
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return REG_NOMATCH;
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if (v->nmatch == 0) /* found, don't need exact location */
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return REG_OKAY;
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/* find starting point and match */
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Assert(cold != NULL);
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open = cold;
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cold = NULL;
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MDEBUG(("between %ld and %ld\n", LOFF(open), LOFF(close)));
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d = newdfa(v, cnfa, cm, &v->dfa1);
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Assert(!(ISERR() && d != NULL));
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NOERR();
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for (begin = open; begin <= close; begin++) {
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MDEBUG(("\nfind trying at %ld\n", LOFF(begin)));
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if (shorter)
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end = shortest(v, d, begin, begin, v->stop, (chr**)NULL, &hitend);
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else
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end = longest(v, d, begin, v->stop, &hitend);
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NOERR();
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if (hitend && cold == NULL)
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cold = begin;
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if (end != NULL)
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break; /* NOTE BREAK OUT */
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}
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Assert(end != NULL); /* search RE succeeded so loop should */
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freedfa(d);
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|
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/* and pin down details */
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Assert(v->nmatch > 0);
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v->pmatch[0].rm_so = OFF(begin);
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v->pmatch[0].rm_eo = OFF(end);
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if (v->g->cflags & REG_EXPECT) {
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if (cold != NULL)
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v->details->rm_extend.rm_so = OFF(cold);
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else
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v->details->rm_extend.rm_so = OFF(v->stop);
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v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
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}
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if (v->nmatch == 1) /* no need for submatches */
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return REG_OKAY;
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|
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/* find submatches */
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zapallsubs(v->pmatch, v->nmatch);
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return cdissect(v, v->g->tree, begin, end);
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}
|
|
|
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/*
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* cfind - find a match for the main NFA (with complications)
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*/
|
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static int cfind(struct vars* v, struct cnfa* cnfa, struct colormap* cm)
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{
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struct dfa* s = NULL;
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struct dfa* d = NULL;
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chr* cold = NULL;
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int ret;
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s = newdfa(v, &v->g->search, cm, &v->dfa1);
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NOERR();
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d = newdfa(v, cnfa, cm, &v->dfa2);
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if (ISERR()) {
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Assert(d == NULL);
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freedfa(s);
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return v->err;
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}
|
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ret = cfindloop(v, cnfa, cm, d, s, &cold);
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|
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freedfa(d);
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freedfa(s);
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NOERR();
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if (v->g->cflags & REG_EXPECT) {
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Assert(v->details != NULL);
|
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if (cold != NULL)
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v->details->rm_extend.rm_so = OFF(cold);
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else
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v->details->rm_extend.rm_so = OFF(v->stop);
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v->details->rm_extend.rm_eo = OFF(v->stop); /* unknown */
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}
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return ret;
|
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}
|
|
|
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/*
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* cfindloop - the heart of cfind
|
|
*/
|
|
static int cfindloop(struct vars* v, struct cnfa* cnfa, struct colormap* cm, struct dfa* d, struct dfa* s,
|
|
chr** coldp) /* where to put coldstart pointer */
|
|
{
|
|
chr* begin = NULL;
|
|
chr* end = NULL;
|
|
chr* cold = NULL;
|
|
chr* open = NULL; /* open and close of range of possible starts */
|
|
chr* close = NULL;
|
|
chr* estart = NULL;
|
|
chr* estop = NULL;
|
|
int er;
|
|
int shorter = v->g->tree->flags & SHORTER;
|
|
int hitend;
|
|
|
|
Assert(d != NULL && s != NULL);
|
|
cold = NULL;
|
|
close = v->search_start;
|
|
do {
|
|
/* Search with the search RE for match range at/beyond "close" */
|
|
MDEBUG(("\ncsearch at %ld\n", LOFF(close)));
|
|
close = shortest(v, s, close, close, v->stop, &cold, (int*)NULL);
|
|
if (close == NULL)
|
|
break; /* no more possible match anywhere */
|
|
Assert(cold != NULL);
|
|
open = cold;
|
|
cold = NULL;
|
|
/* Search for matches starting between "open" and "close" inclusive */
|
|
MDEBUG(("cbetween %ld and %ld\n", LOFF(open), LOFF(close)));
|
|
for (begin = open; begin <= close; begin++) {
|
|
MDEBUG(("\ncfind trying at %ld\n", LOFF(begin)));
|
|
estart = begin;
|
|
estop = v->stop;
|
|
for (;;) {
|
|
/* Here we use the top node's detailed RE */
|
|
if (shorter)
|
|
end = shortest(v, d, begin, estart, estop, (chr**)NULL, &hitend);
|
|
else
|
|
end = longest(v, d, begin, estop, &hitend);
|
|
if (hitend && cold == NULL)
|
|
cold = begin;
|
|
if (end == NULL)
|
|
break; /* no match with this begin point, try next */
|
|
MDEBUG(("tentative end %ld\n", LOFF(end)));
|
|
/* Dissect the potential match to see if it really matches */
|
|
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;
|
|
}
|
|
/* Try next longer/shorter match with same begin point */
|
|
if (shorter) {
|
|
if (end == estop)
|
|
break; /* NOTE BREAK OUT */
|
|
estart = end + 1;
|
|
} else {
|
|
if (end == begin)
|
|
break; /* no more, so try next begin point */
|
|
estop = end - 1;
|
|
}
|
|
} /* end loop over endpoint positions */
|
|
} /* end loop over beginning positions */
|
|
|
|
/*
|
|
* If we get here, there is no possible match starting at or before
|
|
* "close", so consider matches beyond that. We'll do a fresh search
|
|
* with the search RE to find a new promising match range.
|
|
*/
|
|
close++;
|
|
} while (close < v->stop);
|
|
|
|
*coldp = cold;
|
|
return REG_NOMATCH;
|
|
}
|
|
|
|
/*
|
|
* zapallsubs - initialize all subexpression matches to "no match"
|
|
*/
|
|
static void zapallsubs(regmatch_t* p, 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* v, struct subre* 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* v, struct subre* sub, chr* begin, chr* 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).
|
|
* return regexec return code
|
|
*/
|
|
static int 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));
|
|
|
|
/* ... and stack overrun */
|
|
if (STACK_TOO_DEEP(v->re))
|
|
return REG_ETOOBIG;
|
|
|
|
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
|
|
* return regexec return code
|
|
*/
|
|
static int ccondissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
struct dfa* d = NULL;
|
|
struct dfa* d2 = NULL;
|
|
chr* mid = NULL;
|
|
int er;
|
|
|
|
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, (int*)NULL) == end) {
|
|
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, (int*)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);
|
|
}
|
|
|
|
/* can't get here */
|
|
return REG_ASSERT;
|
|
}
|
|
|
|
/*
|
|
* crevcondissect - dissect match for concatenation node, shortest-first
|
|
* return regexec return code
|
|
*/
|
|
static int crevcondissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
struct dfa* d = NULL;
|
|
struct dfa* d2 = NULL;
|
|
chr* mid = NULL;
|
|
int er;
|
|
|
|
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, (int*)NULL) == end) {
|
|
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;
|
|
}
|
|
NOERR();
|
|
/* 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, (chr**)NULL, (int*)NULL);
|
|
NOERR();
|
|
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);
|
|
}
|
|
|
|
/* can't get here */
|
|
return REG_ASSERT;
|
|
}
|
|
|
|
/*
|
|
* cbrdissect - dissect match for backref node
|
|
* return regexec return code
|
|
*/
|
|
static int cbrdissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
int n = t->subno;
|
|
size_t numreps;
|
|
size_t tlen;
|
|
size_t brlen;
|
|
chr* brstring = NULL;
|
|
chr* p = NULL;
|
|
int min = t->min;
|
|
int max = t->max;
|
|
|
|
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 ((int)numreps < min || ((int)numreps > max && max != INFINITY))
|
|
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
|
|
* return regexec return code
|
|
*/
|
|
static int caltdissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
struct dfa* d = NULL;
|
|
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
|
|
* return regexec return code
|
|
*/
|
|
static int citerdissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
struct dfa* d = NULL;
|
|
chr** endpts = NULL;
|
|
chr* limit = NULL;
|
|
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);
|
|
|
|
/*
|
|
* For the moment, assume the minimum number of matches is 1. If zero
|
|
* matches are allowed, and the target string is empty, we are allowed to
|
|
* match regardless of the contents of the iter node --- but we would
|
|
* prefer to match once, so that capturing parens get set. (An example of
|
|
* the concern here is a pattern like "()*\1", which historically this
|
|
* code has allowed to succeed.) Therefore, we deal with the zero-matches
|
|
* case at the bottom, after failing to find any other way to match.
|
|
*/
|
|
min_matches = t->min;
|
|
if (min_matches <= 0) {
|
|
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 != INFINITY)
|
|
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 */
|
|
FREE(endpts);
|
|
|
|
/*
|
|
* Now consider the possibility that we can match to a zero-length string
|
|
* by using zero repetitions.
|
|
*/
|
|
if (t->min == 0 && begin == end) {
|
|
MDEBUG(("%d allowing zero matches\n", t->id));
|
|
return REG_OKAY;
|
|
}
|
|
|
|
MDEBUG(("%d failed\n", t->id));
|
|
return REG_NOMATCH;
|
|
}
|
|
|
|
/*
|
|
* creviterdissect - dissect match for iteration node, shortest-first
|
|
* return regexec return code
|
|
*/
|
|
static int creviterdissect(struct vars* v, struct subre* t, chr* begin, /* beginning of relevant substring */
|
|
chr* end) /* end of same */
|
|
{
|
|
struct dfa* d = NULL;
|
|
chr** endpts = NULL;
|
|
chr* limit = NULL;
|
|
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 != INFINITY)
|
|
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.cpp"
|