int is_match_pike(struct Prog* prog,char* input, char** subp) {
char* sp;
struct Sub* sub;
struct Inst* pc;
int matched = 0;
struct ThreadList *clist, *nlist, *tlist;
int len = prog->len;
clist = threadlist(len);
nlist = threadlist(len);
gen++;
sub = newsub();
int i;
for(i = 0; i < MAXSUB; i++)
sub->sub[i] = NULL;
addthread(clist, thread(prog->start, sub), input);
for(sp = input; ; sp++) {
if(clist->n == 0)
break;
gen++;
for(i = 0; i < clist->n; i++) {
pc = clist->t[i].pc;
sub = clist->t[i].sub;
switch(pc->opcode) {
case Char:
if(*sp != pc->c) {
decref(sub);
break;
}
//printf("%c", pc->c);
case Any:
if(*sp == '\0') {
decref(sub);
break;
}
addthread(nlist, thread(pc+1, sub), sp+1);
break;
case Match:
matched = 1;
int i;
for(i = 0; i < MAXSUB; i++)
subp[i] = sub->sub[i];
for(i = 0; i < clist->n; i++)
decref(clist->t[i].sub);
goto BreakFor;
}
}
//printf("\n");
BreakFor:
tlist = clist;
clist = nlist;
nlist = tlist;
nlist->n = 0;
if(sp == '\0')
break;
}
if(matched)
return sp - input;
return 0;
}
Sub*
update(Sub *s, int i, const char *p)
{
Sub *s1;
int j;
if(s->ref > 1) {
s1 = newsub(s->nsub);
for(j=0; j<s->nsub; j++)
s1->sub[j] = s->sub[j];
s->ref--;
s = s1;
}
s->sub[i] = p;
return s;
}
static void test_add_thread(void) {
char input[] = "ab";
struct Regexp* re = parse(input);
struct Prog* prog = compile(re);
struct Inst* pc = prog->start;
struct Sub* s = newsub();
struct ThreadList* list = threadlist(2);
gen++;
addthread(list, thread(pc, s), input);
gen++;
addthread(list, thread(pc+1, s), input);
assert('a' == list->t[0].pc->c);
assert(Char == list->t[0].pc->opcode);
assert('b' == list->t[1].pc->c);
assert(Char == list->t[0].pc->opcode);
}
int
backtrack(Prog *prog, char *input, char **subp, int nsubp)
{
enum { MAX = 1000 };
Thread ready[MAX];
int i, nready;
Inst *pc;
char *sp;
Sub *sub;
/* queue initial thread */
sub = newsub(nsubp);
for(i=0; i<nsubp; i++)
sub->sub[i] = nil;
ready[0] = thread(prog->start, input, sub);
nready = 1;
/* run threads in stack order */
while(nready > 0) {
--nready; /* pop state for next thread to run */
pc = ready[nready].pc;
sp = ready[nready].sp;
sub = ready[nready].sub;
assert(sub->ref > 0);
for(;;) {
switch(pc->opcode) {
case Char:
if(*sp != pc->c)
goto Dead;
pc++;
sp++;
continue;
case Any:
if(*sp == 0)
goto Dead;
pc++;
sp++;
continue;
case Match:
for(i=0; i<nsubp; i++)
subp[i] = sub->sub[i];
decref(sub);
return 1;
case Jmp:
pc = pc->x;
continue;
case Split:
if(nready >= MAX)
fatal("backtrack overflow");
ready[nready++] = thread(pc->y, sp, incref(sub));
pc = pc->x; /* continue current thread */
continue;
case Save:
sub = update(sub, pc->n, sp);
pc++;
continue;
}
}
Dead:
decref(sub);
}
return 0;
}
