/*
* zapmem - initialize the retry memory of a subtree to zeros
*/
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);
}
/*
* 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 /* 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, (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;
}
/*
* 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;
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->search_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);
*coldp = cold;
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;
}
/*
- 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;
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, 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, 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, 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;
}
