/*
* 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 _ANSI_ARGS_((regex_t *, CONST chr *, size_t, rm_detail_t *, size_t, regmatch_t [], int));
static int find _ANSI_ARGS_((struct vars *, struct cnfa *, struct colormap *));
static int cfind _ANSI_ARGS_((struct vars *, struct cnfa *, struct colormap *));
static int cfindloop _ANSI_ARGS_((struct vars *, struct cnfa *, struct colormap *, struct dfa *, struct dfa *, chr **));
static VOID zapsubs _ANSI_ARGS_((regmatch_t *, size_t));
static VOID zapmem _ANSI_ARGS_((struct vars *, struct subre *));
static VOID subset _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int dissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int condissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int altdissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int cdissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int ccondissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int crevdissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int cbrdissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
static int caltdissect _ANSI_ARGS_((struct vars *, struct subre *, chr *, chr *));
/* === rege_dfa.c === */
static chr *longest _ANSI_ARGS_((struct vars *, struct dfa *, chr *, chr *, int *));
static chr *shortest _ANSI_ARGS_((struct vars *, struct dfa *, chr *, chr *, chr *, chr **, int *));
static chr *lastcold _ANSI_ARGS_((struct vars *, struct dfa *));
static struct dfa *newdfa _ANSI_ARGS_((struct vars *, struct cnfa *, struct colormap *, struct smalldfa *));
static VOID freedfa _ANSI_ARGS_((struct dfa *));
static unsigned hash _ANSI_ARGS_((unsigned *, int));
static struct sset *initialize _ANSI_ARGS_((struct vars *, struct dfa *, chr *));
static struct sset *miss _ANSI_ARGS_((struct vars *, struct dfa *, struct sset *, pcolor, chr *, chr *));
static int lacon _ANSI_ARGS_((struct vars *, struct cnfa *, chr *, pcolor));
static struct sset *getvacant _ANSI_ARGS_((struct vars *, struct dfa *, chr *, chr *));
static struct sset *pickss _ANSI_ARGS_((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(re, string, len, details, nmatch, pmatch, flags)
regex_t *re;
CONST chr *string;
size_t len;
rm_detail_t *details;
size_t nmatch;
regmatch_t pmatch[];
int flags;
{
struct vars var;
register struct vars *v = &var;
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)
return REG_INVARG;
if (re->re_csize != sizeof(chr))
return REG_MIXED;
/* setup */
v->re = re;
v->g = (struct guts *)re->re_guts;
if ((v->g->cflags®_EXPECT) && details == NULL)
return REG_INVARG;
if (v->g->info®_UIMPOSSIBLE)
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)
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);
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);
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(v, cnfa, cm)
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, (int *)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,
(chr **)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(v, cnfa, cm)
struct vars *v;
struct cnfa *cnfa;
struct colormap *cm;
{
struct dfa *s;
struct dfa *d;
chr *cold;
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(v, cnfa, cm, d, s, coldp)
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, (int *)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, (chr **)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(p, n)
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(v, t)
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(v, sub, begin, end)
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(v, t, begin, end)
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 */
break;
case '|': /* alternation */
assert(t->left != NULL);
return altdissect(v, t, begin, end);
break;
case 'b': /* back ref -- shouldn't be calling us! */
return REG_ASSERT;
break;
case '.': /* concatenation */
assert(t->left != NULL && t->right != NULL);
return condissect(v, t, begin, end);
break;
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);
break;
default:
return REG_ASSERT;
break;
}
}
/*
- condissect - determine concatenation subexpression matches (uncomplicated)
^ static int condissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
condissect(v, t, begin, end)
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, (chr **)NULL,
(int *)NULL);
else
mid = longest(v, d, begin, end, (int *)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, (int *)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, (chr **)NULL,
(int *)NULL);
else
mid = longest(v, d, begin, mid-1, (int *)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(v, t, begin, end)
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, (int *)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(v, t, begin, end)
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 */
break;
case '|': /* alternation */
assert(t->left != NULL);
return caltdissect(v, t, begin, end);
break;
case 'b': /* back ref -- shouldn't be calling us! */
assert(t->left == NULL && t->right == NULL);
return cbrdissect(v, t, begin, end);
break;
case '.': /* concatenation */
assert(t->left != NULL && t->right != NULL);
return ccondissect(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);
return er;
break;
default:
return REG_ASSERT;
break;
}
}
/*
- 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(v, t, begin, end)
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);
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, (int *)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 */
er = cdissect(v, t->left, begin, mid);
if (er == REG_OKAY &&
longest(v, d2, mid, end, (int *)NULL) == end &&
(er = cdissect(v, t->right, mid, end)) ==
REG_OKAY)
break; /* NOTE BREAK OUT */
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, (int *)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);
}
/* satisfaction */
MDEBUG(("successful\n"));
freedfa(d);
freedfa(d2);
return REG_OKAY;
}
/*
- 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(v, t, begin, end)
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, (chr **)NULL, (int *)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 */
er = cdissect(v, t->left, begin, mid);
if (er == REG_OKAY &&
longest(v, d2, mid, end, (int *)NULL) == end &&
(er = cdissect(v, t->right, mid, end)) ==
REG_OKAY)
break; /* NOTE BREAK OUT */
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, (chr **)NULL, (int *)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);
}
/* satisfaction */
MDEBUG(("successful\n"));
freedfa(d);
freedfa(d2);
return REG_OKAY;
}
/*
- cbrdissect - determine backref subexpression matches
^ static int cbrdissect(struct vars *, struct subre *, chr *, chr *);
*/
static int /* regexec return code */
cbrdissect(v, t, begin, end)
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(v, t, begin, end)
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, (int *)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"