/*
* 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 find(struct vars *, struct cnfa *, struct colormap *);
static int cfind(struct vars *, struct cnfa *, struct colormap *);
static int cfindloop(struct vars *, struct cnfa *, struct colormap *, struct dfa *, struct dfa *, chr **);
static VOID zapsubs(regmatch_t *, size_t);
static VOID zapmem(struct vars *, struct subre *);
static VOID subset(struct vars *, struct subre *, chr *, chr *);
static int dissect(struct vars *, struct subre *, chr *, chr *);
static int condissect(struct vars *, struct subre *, chr *, chr *);
static int altdissect(struct vars *, struct subre *, chr *, chr *);
static int cdissect(struct vars *, struct subre *, chr *, chr *);
static int ccondissect(struct vars *, struct subre *, chr *, chr *);
static int crevdissect(struct vars *, struct subre *, chr *, chr *);
static int cbrdissect(struct vars *, struct subre *, chr *, chr *);
static int caltdissect(struct vars *, struct subre *, chr *, chr *);
/* === rege_dfa.c === */
static chr *longest(struct vars *, struct dfa *, chr *, chr *, int *);
static chr *shortest(struct vars *, struct dfa *, chr *, chr *, chr *, chr **, int *);
static chr *lastcold(struct vars *, struct dfa *);
static struct dfa *newdfa(struct vars *, struct cnfa *, struct colormap *, struct smalldfa *);
static VOID freedfa(struct dfa *);
static unsigned hash(unsigned *, int);
static struct sset *initialize(struct vars *, struct dfa *, chr *);
static struct sset *miss(struct vars *, struct dfa *, struct sset *, pcolor, chr *, chr *);
static int lacon(struct vars *, struct cnfa *, chr *, pcolor);
static struct sset *getvacant(struct vars *, struct dfa *, chr *, chr *);
static struct sset *pickss(struct vars *, struct dfa *, chr *, chr *);
/* 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;
size_t n;
int backref;
#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®_EXPECT) && details == NULL) {
FreeVars(v);
return REG_INVARG;
}
if (v->g->info®_UIMPOSSIBLE) {
FreeVars(v);
return REG_NOMATCH;
}
backref = (v->g->info®_UBACKREF) ? 1 : 0;
v->eflags = flags;
if (v->g->cflags®_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 = cfind(v, &v->g->tree->cnfa, &v->g->cmap);
} else {
st = find(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) {
zapsubs(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;
}
/*
- find - find a match for the main NFA (no-complications case)
^ static int find(struct vars *, struct cnfa *, struct colormap *);
*/
static int
find(
struct vars *v,
struct cnfa *cnfa,
struct colormap *cm)
{
struct dfa *s;
struct dfa *d;
chr *begin;
chr *end = NULL;
chr *cold;
chr *open; /* Open and close of range of possible
* starts */
chr *close;
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®_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®_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.
*/
zapsubs(v->pmatch, v->nmatch);
return dissect(v, v->g->tree, begin, end);
}
/*
- cfind - find a match for the main NFA (with complications)
^ static int cfind(struct vars *, struct cnfa *, struct colormap *);
*/
static int
cfind(
struct vars *v,
struct cnfa *cnfa,
struct colormap *cm)
{
struct dfa *s;
struct dfa *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 = cfindloop(v, cnfa, cm, 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;
}
/*
- cfindloop - the heart of cfind
^ static int cfindloop(struct vars *, struct cnfa *, struct colormap *,
^ struct dfa *, struct dfa *, chr **);
*/
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;
chr *end;
chr *cold;
chr *open; /* Open and close of range of possible
* starts */
chr *close;
chr *estart;
chr *estop;
int er;
int shorter = v->g->tree->flags&SHORTER;
int hitend;
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(("\ncfind 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)));
zapsubs(v->pmatch, v->nmatch);
zapmem(v, v->g->tree);
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);
return er;
}
if ((shorter) ? end == estop : end == begin) {
/*
* No point in trying again.
*/
*coldp = cold;
return REG_NOMATCH;
}
/*
* Go around and try again
*/
if (shorter) {
estart = end + 1;
} else {
estop = end - 1;
}
}
}
} while (close < v->stop);
*coldp = cold;
return REG_NOMATCH;
}
/*
- zapsubs - initialize the subexpression matches to "no match"
^ static VOID zapsubs(regmatch_t *, size_t);
*/
static void
zapsubs(
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;
}
}
/*
- zapmem - initialize the retry memory of a subtree to zeros
^ static VOID zapmem(struct vars *, struct subre *);
*/
static void
zapmem(
struct vars *v,
struct subre *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) {
zapmem(v, t->left);
}
if (t->right != NULL) {
zapmem(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 *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);
}
/*
- dissect - determine subexpression matches (uncomplicated case)
^ static int dissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
dissect(
struct vars *v,
struct subre *t,
chr *begin, /* beginning of relevant substring */
chr *end) /* end of same */
{
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 altdissect(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 condissect(v, t, begin, end);
case '(': /* capturing */
assert(t->left != NULL && t->right == NULL);
assert(t->subno > 0);
subset(v, t, begin, end);
return dissect(v, t->left, begin, end);
default:
return REG_ASSERT;
}
}
/*
- condissect - determine concatenation subexpression matches (uncomplicated)
^ static int condissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
condissect(
struct vars *v,
struct subre *t,
chr *begin, /* beginning of relevant substring */
chr *end) /* end of same */
{
struct dfa *d;
struct dfa *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);
}
/*
- altdissect - determine alternative subexpression matches (uncomplicated)
^ static int altdissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
altdissect(
struct vars *v,
struct subre *t,
chr *begin, /* beginning of relevant substring */
chr *end) /* end of same */
{
struct dfa *d;
int i;
assert(t != NULL);
assert(t->op == '|');
for (i = 0; t != NULL; t = t->right, i++) {
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?!? */
}
/*
- cdissect - 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 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);
return REG_OKAY; /* no action, parent did the work */
case '|': /* alternation */
assert(t->left != NULL);
return caltdissect(v, t, begin, end);
case 'b': /* back ref -- shouldn't be calling us! */
assert(t->left == NULL && t->right == NULL);
return cbrdissect(v, t, begin, end);
case '.': /* concatenation */
assert(t->left != NULL && t->right != NULL);
return ccondissect(v, t, begin, end);
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);
}
return er;
default:
return REG_ASSERT;
}
}
/*
- ccondissect - 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 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;
int er;
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 crevdissect(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) {
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"));
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;
zapmem(v, t->left);
zapmem(v, t->right);
}
}
/*
- crevdissect - 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 crevdissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
crevdissect(
struct vars *v,
struct subre *t,
chr *begin, /* beginning of relevant substring */
chr *end) /* end of same */
{
struct dfa *d;
struct dfa *d2;
chr *mid;
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);
/*
* 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) {
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"));
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;
zapmem(v, t->left);
zapmem(v, t->right);
}
}
/*
- cbrdissect - determine backref subexpression matches
^ 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 i;
int n = t->subno;
size_t len;
chr *paren;
chr *p;
chr *stop;
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->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 */
}
/*
- caltdissect - determine alternative subexpression matches (w. complications)
^ 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;
#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 */
if (t == NULL) {
return REG_NOMATCH;
}
assert(t->op == '|');
if (v->mem[t->retry] == TRIED) {
return caltdissect(v, t->right, begin, end);
}
MDEBUG(("calt n%d\n", t->retry));
assert(t->left != NULL);
if (v->mem[t->retry] == UNTRIED) {
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;
return caltdissect(v, t->right, begin, end);
}
freedfa(d);
MDEBUG(("calt matched\n"));
v->mem[t->retry] = TRYING;
}
er = cdissect(v, t->left, begin, end);
if (er != REG_NOMATCH) {
return er;
}
v->mem[t->retry] = TRIED;
return caltdissect(v, t->right, begin, end);
}
#include "rege_dfa.c"
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
|
