summaryrefslogtreecommitdiffstats
path: root/generic/regexec.c
diff options
context:
space:
mode:
Diffstat (limited to 'generic/regexec.c')
-rw-r--r--generic/regexec.c1218
1 files changed, 1218 insertions, 0 deletions
diff --git a/generic/regexec.c b/generic/regexec.c
new file mode 100644
index 0000000..ad4b6e6
--- /dev/null
+++ b/generic/regexec.c
@@ -0,0 +1,1218 @@
+/*
+ * re_*exec and friends - match REs
+ *
+ * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
+ *
+ * Development of this software was funded, in part, by Cray Research Inc.,
+ * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
+ * Corporation, none of whom are responsible for the results. The author
+ * thanks all of them.
+ *
+ * Redistribution and use in source and binary forms -- with or without
+ * modification -- are permitted for any purpose, provided that
+ * redistributions in source form retain this entire copyright notice and
+ * indicate the origin and nature of any modifications.
+ *
+ * I'd appreciate being given credit for this package in the documentation of
+ * software which uses it, but that is not a requirement.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "regguts.h"
+
+/*
+ * Lazy-DFA representation.
+ */
+
+struct arcp { /* "pointer" to an outarc */
+ struct sset *ss;
+ color co;
+};
+
+struct sset { /* state set */
+ unsigned *states; /* pointer to bitvector */
+ unsigned hash; /* hash of bitvector */
+#define HASH(bv, nw) (((nw) == 1) ? *(bv) : hash(bv, nw))
+#define HIT(h,bv,ss,nw) ((ss)->hash == (h) && ((nw) == 1 || \
+ memcmp(VS(bv), VS((ss)->states), (nw)*sizeof(unsigned)) == 0))
+ int flags;
+#define STARTER 01 /* the initial state set */
+#define POSTSTATE 02 /* includes the goal state */
+#define LOCKED 04 /* locked in cache */
+#define NOPROGRESS 010 /* zero-progress state set */
+ struct arcp ins; /* chain of inarcs pointing here */
+ chr *lastseen; /* last entered on arrival here */
+ struct sset **outs; /* outarc vector indexed by color */
+ struct arcp *inchain; /* chain-pointer vector for outarcs */
+};
+
+struct dfa {
+ int nssets; /* size of cache */
+ int nssused; /* how many entries occupied yet */
+ int nstates; /* number of states */
+ int ncolors; /* length of outarc and inchain vectors */
+ int wordsper; /* length of state-set bitvectors */
+ struct sset *ssets; /* state-set cache */
+ unsigned *statesarea; /* bitvector storage */
+ unsigned *work; /* pointer to work area within statesarea */
+ struct sset **outsarea; /* outarc-vector storage */
+ struct arcp *incarea; /* inchain storage */
+ struct cnfa *cnfa;
+ struct colormap *cm;
+ chr *lastpost; /* location of last cache-flushed success */
+ chr *lastnopr; /* location of last cache-flushed NOPROGRESS */
+ struct sset *search; /* replacement-search-pointer memory */
+ int cptsmalloced; /* were the areas individually malloced? */
+ char *mallocarea; /* self, or master malloced area, or NULL */
+};
+
+#define WORK 1 /* number of work bitvectors needed */
+
+/*
+ * Setup for non-malloc allocation for small cases.
+ */
+
+#define FEWSTATES 20 /* must be less than UBITS */
+#define FEWCOLORS 15
+struct smalldfa {
+ struct dfa dfa;
+ struct sset ssets[FEWSTATES*2];
+ unsigned statesarea[FEWSTATES*2 + WORK];
+ struct sset *outsarea[FEWSTATES*2 * FEWCOLORS];
+ struct arcp incarea[FEWSTATES*2 * FEWCOLORS];
+};
+#define DOMALLOC ((struct smalldfa *)NULL) /* force malloc */
+
+/*
+ * Internal variables, bundled for easy passing around.
+ */
+
+struct vars {
+ regex_t *re;
+ struct guts *g;
+ int eflags; /* copies of arguments */
+ size_t nmatch;
+ regmatch_t *pmatch;
+ rm_detail_t *details;
+ chr *start; /* start of string */
+ chr *stop; /* just past end of string */
+ int err; /* error code if any (0 none) */
+ regoff_t *mem; /* memory vector for backtracking */
+ struct smalldfa dfa1;
+ struct smalldfa dfa2;
+};
+#define VISERR(vv) ((vv)->err != 0) /* have we seen an error yet? */
+#define ISERR() VISERR(v)
+#define VERR(vv,e) (((vv)->err) ? (vv)->err : ((vv)->err = (e)))
+#define ERR(e) VERR(v, e) /* record an error */
+#define NOERR() {if (ISERR()) return v->err;} /* if error seen, return it */
+#define OFF(p) ((p) - v->start)
+#define LOFF(p) ((long)OFF(p))
+
+/*
+ * forward declarations
+ */
+/* =====^!^===== begin forwards =====^!^===== */
+/* automatically gathered by fwd; do not hand-edit */
+/* === regexec.c === */
+int exec(regex_t *, const chr *, size_t, rm_detail_t *, size_t, regmatch_t [], int);
+static int simpleFind(struct vars *const, struct cnfa *const, struct colormap *const);
+static int complicatedFind(struct vars *const, struct cnfa *const, struct colormap *const);
+static int complicatedFindLoop(struct vars *const, struct cnfa *const, struct colormap *const, struct dfa *const, struct dfa *const, chr **const);
+static void zapSubexpressions(regmatch_t *const, const size_t);
+static void zapSubtree(struct vars *const, struct subre *const);
+static void subset(struct vars *const, struct subre *const, chr *const, chr *const);
+static int dissect(struct vars *const, struct subre *, chr *const, chr *const);
+static int concatenationDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int alternationDissect(struct vars *const, struct subre *, chr *const, chr *const);
+static inline int complicatedDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int complicatedCapturingDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int complicatedConcatenationDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int complicatedReversedDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int complicatedBackrefDissect(struct vars *const, struct subre *const, chr *const, chr *const);
+static int complicatedAlternationDissect(struct vars *const, struct subre *, chr *const, chr *const);
+/* === rege_dfa.c === */
+static chr *longest(struct vars *const, struct dfa *const, chr *const, chr *const, int *const);
+static chr *shortest(struct vars *const, struct dfa *const, chr *const, chr *const, chr *const, chr **const, int *const);
+static chr *lastCold(struct vars *const, struct dfa *const);
+static struct dfa *newDFA(struct vars *const, struct cnfa *const, struct colormap *const, struct smalldfa *);
+static void freeDFA(struct dfa *const);
+static unsigned hash(unsigned *const, const int);
+static struct sset *initialize(struct vars *const, struct dfa *const, chr *const);
+static struct sset *miss(struct vars *const, struct dfa *const, struct sset *const, const pcolor, chr *const, chr *const);
+static int checkLAConstraint(struct vars *const, struct cnfa *const, chr *const, const pcolor);
+static struct sset *getVacantSS(struct vars *const, struct dfa *const, chr *const, chr *const);
+static struct sset *pickNextSS(struct vars *const, struct dfa *const, chr *const, chr *const);
+/* automatically gathered by fwd; do not hand-edit */
+/* =====^!^===== end forwards =====^!^===== */
+
+/*
+ - exec - match regular expression
+ ^ int exec(regex_t *, const chr *, size_t, rm_detail_t *,
+ ^ size_t, regmatch_t [], int);
+ */
+int
+exec(
+ regex_t *re,
+ const chr *string,
+ size_t len,
+ rm_detail_t *details,
+ size_t nmatch,
+ regmatch_t pmatch[],
+ int flags)
+{
+ AllocVars(v);
+ int st, backref;
+ size_t n;
+#define LOCALMAT 20
+ regmatch_t mat[LOCALMAT];
+#define LOCALMEM 40
+ regoff_t mem[LOCALMEM];
+
+ /*
+ * Sanity checks.
+ */
+
+ if (re == NULL || string == NULL || re->re_magic != REMAGIC) {
+ FreeVars(v);
+ return REG_INVARG;
+ }
+ if (re->re_csize != sizeof(chr)) {
+ FreeVars(v);
+ return REG_MIXED;
+ }
+
+ /*
+ * Setup.
+ */
+
+ v->re = re;
+ v->g = (struct guts *)re->re_guts;
+ if ((v->g->cflags&REG_EXPECT) && details == NULL) {
+ FreeVars(v);
+ return REG_INVARG;
+ }
+ if (v->g->info&REG_UIMPOSSIBLE) {
+ FreeVars(v);
+ return REG_NOMATCH;
+ }
+ backref = (v->g->info&REG_UBACKREF) ? 1 : 0;
+ v->eflags = flags;
+ if (v->g->cflags&REG_NOSUB) {
+ nmatch = 0; /* override client */
+ }
+ v->nmatch = nmatch;
+ if (backref) {
+ /*
+ * Need work area.
+ */
+
+ if (v->g->nsub + 1 <= LOCALMAT) {
+ v->pmatch = mat;
+ } else {
+ v->pmatch = (regmatch_t *)
+ MALLOC((v->g->nsub + 1) * sizeof(regmatch_t));
+ }
+ if (v->pmatch == NULL) {
+ FreeVars(v);
+ return REG_ESPACE;
+ }
+ v->nmatch = v->g->nsub + 1;
+ } else {
+ v->pmatch = pmatch;
+ }
+ v->details = details;
+ v->start = (chr *)string;
+ v->stop = (chr *)string + len;
+ v->err = 0;
+ if (backref) {
+ /*
+ * Need retry memory.
+ */
+
+ assert(v->g->ntree >= 0);
+ n = (size_t)v->g->ntree;
+ if (n <= LOCALMEM) {
+ v->mem = mem;
+ } else {
+ v->mem = (regoff_t *) MALLOC(n*sizeof(regoff_t));
+ }
+ if (v->mem == NULL) {
+ if (v->pmatch != pmatch && v->pmatch != mat) {
+ FREE(v->pmatch);
+ }
+ FreeVars(v);
+ return REG_ESPACE;
+ }
+ } else {
+ v->mem = NULL;
+ }
+
+ /*
+ * Do it.
+ */
+
+ assert(v->g->tree != NULL);
+ if (backref) {
+ st = complicatedFind(v, &v->g->tree->cnfa, &v->g->cmap);
+ } else {
+ st = simpleFind(v, &v->g->tree->cnfa, &v->g->cmap);
+ }
+
+ /*
+ * Copy (portion of) match vector over if necessary.
+ */
+
+ if (st == REG_OKAY && v->pmatch != pmatch && nmatch > 0) {
+ zapSubexpressions(pmatch, nmatch);
+ n = (nmatch < v->nmatch) ? nmatch : v->nmatch;
+ memcpy(VS(pmatch), VS(v->pmatch), n*sizeof(regmatch_t));
+ }
+
+ /*
+ * Clean up.
+ */
+
+ if (v->pmatch != pmatch && v->pmatch != mat) {
+ FREE(v->pmatch);
+ }
+ if (v->mem != NULL && v->mem != mem) {
+ FREE(v->mem);
+ }
+ FreeVars(v);
+ return st;
+}
+
+/*
+ - simpleFind - find a match for the main NFA (no-complications case)
+ ^ static int simpleFind(struct vars *, struct cnfa *, struct colormap *);
+ */
+static int
+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.
+ */
+
+ s = newDFA(v, &v->g->search, cm, &v->dfa1);
+ assert(!(ISERR() && s != NULL));
+ NOERR();
+ MDEBUG(("\nsearch at %ld\n", LOFF(v->start)));
+ cold = NULL;
+ close = shortest(v, s, v->start, v->start, v->stop, &cold, NULL);
+ freeDFA(s);
+ NOERR();
+ if (v->g->cflags&REG_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);
+ }
+ NOERR();
+ 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&REG_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;
+ }
+
+ /*
+ * Submatches.
+ */
+
+ zapSubexpressions(v->pmatch, v->nmatch);
+ return dissect(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, cnfa, cm, d, s, &cold);
+
+ freeDFA(d);
+ freeDFA(s);
+ NOERR();
+ if (v->g->cflags&REG_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 cnfa *, struct colormap *,
+ ^ struct dfa *, struct dfa *, chr **);
+ */
+static int
+complicatedFindLoop(
+ struct vars *const v,
+ struct cnfa *const cnfa,
+ struct colormap *const cm,
+ 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)));
+ zapSubexpressions(v->pmatch, v->nmatch);
+ zapSubtree(v, v->g->tree);
+ er = complicatedDissect(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);
+ 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;
+}
+
+/*
+ - zapSubexpressions - initialize the subexpression matches to "no match"
+ ^ static void zapSubexpressions(regmatch_t *, size_t);
+ */
+static void
+zapSubexpressions(
+ 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;
+ }
+}
+
+/*
+ - zapSubtree - initialize the retry memory of a subtree to zeros
+ ^ static void zapSubtree(struct vars *, struct subre *);
+ */
+static void
+zapSubtree(
+ struct vars *const v,
+ struct subre *const t)
+{
+ if (t == NULL) {
+ return;
+ }
+
+ assert(v->mem != NULL);
+ v->mem[t->retry] = 0;
+ if (t->op == '(') {
+ assert(t->subno > 0);
+ v->pmatch[t->subno].rm_so = -1;
+ v->pmatch[t->subno].rm_eo = -1;
+ }
+
+ if (t->left != NULL) {
+ zapSubtree(v, t->left);
+ }
+ if (t->right != NULL) {
+ zapSubtree(v, t->right);
+ }
+}
+
+/*
+ - subset - set any subexpression relevant to 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);
+}
+
+/*
+ - dissect - determine subexpression matches (uncomplicated case)
+ ^ static int dissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+dissect(
+ struct vars *const v,
+ struct subre *t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+#ifndef COMPILER_DOES_TAILCALL_OPTIMIZATION
+ restart:
+#endif
+ assert(t != NULL);
+ MDEBUG(("dissect %ld-%ld\n", LOFF(begin), LOFF(end)));
+
+ switch (t->op) {
+ case '=': /* terminal node */
+ assert(t->left == NULL && t->right == NULL);
+ return REG_OKAY; /* no action, parent did the work */
+ case '|': /* alternation */
+ assert(t->left != NULL);
+ return alternationDissect(v, t, begin, end);
+ case 'b': /* back ref -- shouldn't be calling us! */
+ return REG_ASSERT;
+ case '.': /* concatenation */
+ assert(t->left != NULL && t->right != NULL);
+ return concatenationDissect(v, t, begin, end);
+ case '(': /* capturing */
+ assert(t->left != NULL && t->right == NULL);
+ assert(t->subno > 0);
+ subset(v, t, begin, end);
+#ifndef COMPILER_DOES_TAILCALL_OPTIMIZATION
+ t = t->left;
+ goto restart;
+#else
+ return dissect(v, t->left, begin, end);
+#endif
+ default:
+ return REG_ASSERT;
+ }
+}
+
+/*
+ - concatenationDissect - determine concatenation subexpression matches
+ - (uncomplicated)
+ ^ static int concatenationDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+concatenationDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ struct dfa *d, *d2;
+ chr *mid;
+ int i;
+ int shorter = (t->left->flags&SHORTER) ? 1 : 0;
+ chr *stop = (shorter) ? end : begin;
+
+ assert(t->op == '.');
+ assert(t->left != NULL && t->left->cnfa.nstates > 0);
+ assert(t->right != NULL && t->right->cnfa.nstates > 0);
+
+ d = newDFA(v, &t->left->cnfa, &v->g->cmap, &v->dfa1);
+ NOERR();
+ d2 = newDFA(v, &t->right->cnfa, &v->g->cmap, &v->dfa2);
+ if (ISERR()) {
+ assert(d2 == NULL);
+ freeDFA(d);
+ return v->err;
+ }
+
+ /*
+ * Pick a tentative midpoint.
+ */
+
+ if (shorter) {
+ mid = shortest(v, d, begin, begin, end, NULL, NULL);
+ } else {
+ mid = longest(v, d, begin, end, NULL);
+ }
+ if (mid == NULL) {
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_ASSERT;
+ }
+ MDEBUG(("tentative midpoint %ld\n", LOFF(mid)));
+
+ /*
+ * Iterate until satisfaction or failure.
+ */
+
+ while (longest(v, d2, mid, end, NULL) != end) {
+ /*
+ * That midpoint didn't work, find a new one.
+ */
+
+ if (mid == stop) {
+ /*
+ * All possibilities exhausted!
+ */
+
+ MDEBUG(("no midpoint!\n"));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_ASSERT;
+ }
+ if (shorter) {
+ mid = shortest(v, d, begin, mid+1, end, NULL, NULL);
+ } else {
+ mid = longest(v, d, begin, mid-1, NULL);
+ }
+ if (mid == NULL) {
+ /*
+ * Failed to find a new one!
+ */
+
+ MDEBUG(("failed midpoint!\n"));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_ASSERT;
+ }
+ MDEBUG(("new midpoint %ld\n", LOFF(mid)));
+ }
+
+ /*
+ * Satisfaction.
+ */
+
+ MDEBUG(("successful\n"));
+ freeDFA(d);
+ freeDFA(d2);
+ i = dissect(v, t->left, begin, mid);
+ if (i != REG_OKAY) {
+ return i;
+ }
+ return dissect(v, t->right, mid, end);
+}
+
+/*
+ - alternationDissect - determine alternative subexpression matches (uncomplicated)
+ ^ static int alternationDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+alternationDissect(
+ struct vars *const v,
+ struct subre *t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ int i;
+
+ assert(t != NULL);
+ assert(t->op == '|');
+
+ for (i = 0; t != NULL; t = t->right, i++) {
+ struct dfa *d;
+
+ MDEBUG(("trying %dth\n", i));
+ assert(t->left != NULL && t->left->cnfa.nstates > 0);
+ d = newDFA(v, &t->left->cnfa, &v->g->cmap, &v->dfa1);
+ if (ISERR()) {
+ return v->err;
+ }
+ if (longest(v, d, begin, end, NULL) == end) {
+ MDEBUG(("success\n"));
+ freeDFA(d);
+ return dissect(v, t->left, begin, end);
+ }
+ freeDFA(d);
+ }
+ return REG_ASSERT; /* none of them matched?!? */
+}
+
+/*
+ - complicatedDissect - determine subexpression matches (with complications)
+ * The retry memory stores the offset of the trial midpoint from begin, plus 1
+ * so that 0 uniquely means "clean slate".
+ ^ static int complicatedDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static inline int /* regexec return code */
+complicatedDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ assert(t != NULL);
+ MDEBUG(("complicatedDissect %ld-%ld %c\n", LOFF(begin), LOFF(end), t->op));
+
+ switch (t->op) {
+ case '=': /* terminal node */
+ assert(t->left == NULL && t->right == NULL);
+ return REG_OKAY; /* no action, parent did the work */
+ case '|': /* alternation */
+ assert(t->left != NULL);
+ return complicatedAlternationDissect(v, t, begin, end);
+ case 'b': /* back ref -- shouldn't be calling us! */
+ assert(t->left == NULL && t->right == NULL);
+ return complicatedBackrefDissect(v, t, begin, end);
+ case '.': /* concatenation */
+ assert(t->left != NULL && t->right != NULL);
+ return complicatedConcatenationDissect(v, t, begin, end);
+ case '(': /* capturing */
+ assert(t->left != NULL && t->right == NULL);
+ assert(t->subno > 0);
+ return complicatedCapturingDissect(v, t, begin, end);
+ default:
+ return REG_ASSERT;
+ }
+}
+
+static int /* regexec return code */
+complicatedCapturingDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ int er = complicatedDissect(v, t->left, begin, end);
+
+ if (er == REG_OKAY) {
+ subset(v, t, begin, end);
+ }
+ return er;
+}
+
+/*
+ - complicatedConcatenationDissect - concatenation subexpression matches (with complications)
+ * The retry memory stores the offset of the trial midpoint from begin, plus 1
+ * so that 0 uniquely means "clean slate".
+ ^ static int complicatedConcatenationDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+complicatedConcatenationDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const 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);
+
+ if (t->left->flags&SHORTER) { /* reverse scan */
+ return complicatedReversedDissect(v, t, begin, end);
+ }
+
+ d = newDFA(v, &t->left->cnfa, &v->g->cmap, DOMALLOC);
+ if (ISERR()) {
+ return v->err;
+ }
+ d2 = newDFA(v, &t->right->cnfa, &v->g->cmap, DOMALLOC);
+ if (ISERR()) {
+ freeDFA(d);
+ return v->err;
+ }
+ MDEBUG(("cConcat %d\n", t->retry));
+
+ /*
+ * Pick a tentative midpoint.
+ */
+
+ if (v->mem[t->retry] == 0) {
+ mid = longest(v, d, begin, end, NULL);
+ if (mid == NULL) {
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_NOMATCH;
+ }
+ MDEBUG(("tentative midpoint %ld\n", LOFF(mid)));
+ v->mem[t->retry] = (mid - begin) + 1;
+ } else {
+ mid = begin + (v->mem[t->retry] - 1);
+ MDEBUG(("working 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 = complicatedDissect(v, t->left, begin, mid);
+
+ if (er == REG_OKAY) {
+ er = complicatedDissect(v, t->right, mid, end);
+ if (er == REG_OKAY) {
+ /*
+ * Satisfaction.
+ */
+
+ MDEBUG(("successful\n"));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_OKAY;
+ }
+ }
+ if ((er != REG_OKAY) && (er != REG_NOMATCH)) {
+ freeDFA(d);
+ freeDFA(d2);
+ return er;
+ }
+ }
+
+ /*
+ * That midpoint didn't work, find a new one.
+ */
+
+ if (mid == begin) {
+ /*
+ * All possibilities exhausted.
+ */
+
+ MDEBUG(("%d no midpoint\n", t->retry));
+ freeDFA(d);
+ freeDFA(d2);
+ 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->retry));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_NOMATCH;
+ }
+ MDEBUG(("%d: new midpoint %ld\n", t->retry, LOFF(mid)));
+ v->mem[t->retry] = (mid - begin) + 1;
+ zapSubtree(v, t->left);
+ zapSubtree(v, t->right);
+ }
+}
+
+/*
+ - complicatedReversedDissect - determine backref shortest-first subexpression
+ - matches
+ * The retry memory stores the offset of the trial midpoint from begin, plus 1
+ * so that 0 uniquely means "clean slate".
+ ^ static int complicatedReversedDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+complicatedReversedDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const 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);
+
+ /*
+ * Concatenation -- need to split the substring between parts.
+ */
+
+ d = newDFA(v, &t->left->cnfa, &v->g->cmap, DOMALLOC);
+ if (ISERR()) {
+ return v->err;
+ }
+ d2 = newDFA(v, &t->right->cnfa, &v->g->cmap, DOMALLOC);
+ if (ISERR()) {
+ freeDFA(d);
+ return v->err;
+ }
+ MDEBUG(("cRev %d\n", t->retry));
+
+ /*
+ * Pick a tentative midpoint.
+ */
+
+ if (v->mem[t->retry] == 0) {
+ mid = shortest(v, d, begin, begin, end, NULL, NULL);
+ if (mid == NULL) {
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_NOMATCH;
+ }
+ MDEBUG(("tentative midpoint %ld\n", LOFF(mid)));
+ v->mem[t->retry] = (mid - begin) + 1;
+ } else {
+ mid = begin + (v->mem[t->retry] - 1);
+ MDEBUG(("working 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 = complicatedDissect(v, t->left, begin, mid);
+
+ if (er == REG_OKAY) {
+ er = complicatedDissect(v, t->right, mid, end);
+ if (er == REG_OKAY) {
+ /*
+ * Satisfaction.
+ */
+
+ MDEBUG(("successful\n"));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_OKAY;
+ }
+ }
+ if (er != REG_OKAY && er != REG_NOMATCH) {
+ freeDFA(d);
+ freeDFA(d2);
+ return er;
+ }
+ }
+
+ /*
+ * That midpoint didn't work, find a new one.
+ */
+
+ if (mid == end) {
+ /*
+ * All possibilities exhausted.
+ */
+
+ MDEBUG(("%d no midpoint\n", t->retry));
+ freeDFA(d);
+ freeDFA(d2);
+ 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->retry));
+ freeDFA(d);
+ freeDFA(d2);
+ return REG_NOMATCH;
+ }
+ MDEBUG(("%d: new midpoint %ld\n", t->retry, LOFF(mid)));
+ v->mem[t->retry] = (mid - begin) + 1;
+ zapSubtree(v, t->left);
+ zapSubtree(v, t->right);
+ }
+}
+
+/*
+ - complicatedBackrefDissect - determine backref subexpression matches
+ ^ static int complicatedBackrefDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+complicatedBackrefDissect(
+ struct vars *const v,
+ struct subre *const t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ int i, n = t->subno, min = t->min, max = t->max;
+ chr *paren, *p, *stop;
+ size_t len;
+
+ 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->retry, n, min, max));
+
+ if (v->pmatch[n].rm_so == -1) {
+ return REG_NOMATCH;
+ }
+ paren = v->start + v->pmatch[n].rm_so;
+ len = v->pmatch[n].rm_eo - v->pmatch[n].rm_so;
+
+ /*
+ * No room to maneuver -- retries are pointless.
+ */
+
+ if (v->mem[t->retry]) {
+ return REG_NOMATCH;
+ }
+ v->mem[t->retry] = 1;
+
+ /*
+ * Special-case zero-length string.
+ */
+
+ if (len == 0) {
+ if (begin == end) {
+ return REG_OKAY;
+ }
+ return REG_NOMATCH;
+ }
+
+ /*
+ * And too-short string.
+ */
+
+ assert(end >= begin);
+ if ((size_t)(end - begin) < len) {
+ return REG_NOMATCH;
+ }
+ stop = end - len;
+
+ /*
+ * Count occurrences.
+ */
+
+ i = 0;
+ for (p = begin; p <= stop && (i < max || max == INFINITY); p += len) {
+ if (v->g->compare(paren, p, len) != 0) {
+ break;
+ }
+ i++;
+ }
+ MDEBUG(("cbackref found %d\n", i));
+
+ /*
+ * And sort it out.
+ */
+
+ if (p != end) { /* didn't consume all of it */
+ return REG_NOMATCH;
+ }
+ if (min <= i && (i <= max || max == INFINITY)) {
+ return REG_OKAY;
+ }
+ return REG_NOMATCH; /* out of range */
+}
+
+/*
+ - complicatedAlternationDissect - determine alternative subexpression matches (w.
+ - complications)
+ ^ static int complicatedAlternationDissect(struct vars *, struct subre *, chr *, chr *);
+ */
+static int /* regexec return code */
+complicatedAlternationDissect(
+ struct vars *const v,
+ struct subre *t,
+ chr *const begin, /* beginning of relevant substring */
+ chr *const end) /* end of same */
+{
+ int er;
+#define UNTRIED 0 /* not yet tried at all */
+#define TRYING 1 /* top matched, trying submatches */
+#define TRIED 2 /* top didn't match or submatches exhausted */
+
+#ifndef COMPILER_DOES_TAILCALL_OPTIMIZATION
+ if (0) {
+ doRight:
+ t = t->right;
+ }
+#endif
+ if (t == NULL) {
+ return REG_NOMATCH;
+ }
+ assert(t->op == '|');
+ if (v->mem[t->retry] == TRIED) {
+ goto doRight;
+ }
+
+ MDEBUG(("cAlt n%d\n", t->retry));
+ assert(t->left != NULL);
+
+ if (v->mem[t->retry] == UNTRIED) {
+ struct dfa *d = newDFA(v, &t->left->cnfa, &v->g->cmap, DOMALLOC);
+
+ if (ISERR()) {
+ return v->err;
+ }
+ if (longest(v, d, begin, end, NULL) != end) {
+ freeDFA(d);
+ v->mem[t->retry] = TRIED;
+ goto doRight;
+ }
+ freeDFA(d);
+ MDEBUG(("cAlt matched\n"));
+ v->mem[t->retry] = TRYING;
+ }
+
+ er = complicatedDissect(v, t->left, begin, end);
+ if (er != REG_NOMATCH) {
+ return er;
+ }
+
+ v->mem[t->retry] = TRIED;
+#ifndef COMPILER_DOES_TAILCALL_OPTIMIZATION
+ goto doRight;
+#else
+ doRight:
+ return complicatedAlternationDissect(v, t->right, begin, end);
+#endif
+}
+
+#include "rege_dfa.c"
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */
generated by cgit v0.12 at 2025-10-31 19:04:43 (GMT)