static void apply_force_clear_stack(struct apply_handle *h) {
/* Make sure stack is empty and marks reset */
if (!apply_stack_isempty(h)) {
*(h->marks+(h->gstates+h->ptr)->state_no) = 0;
while (!apply_stack_isempty(h)) {
apply_stack_pop(h);
*(h->marks+(h->gstates+h->ptr)->state_no) = 0;
}
h->iterator = 0;
h->iterate_old = 0;
apply_stack_clear(h);
}
}
char *apply_net(struct apply_handle *h) {
char *fname, *fvalue;
int eatupi, eatupo, symin, symout, f, fneg;
int vcount, msource, mtarget;
/* We perform a basic DFS on the graph, with two minor complications: */
/* 1. We keep a mark for each state which indicates whether it is seen */
/* on the current "run." If we reach a marked state, we terminate. */
/* As we pop a position, we also unmark the state we came from. */
/* If we're matching against a string, we terminate if the mark */
/* is set and ipos is the same as last time we saw the flag, i.e. */
/* we've traversed a loop without consuming an input symbol */
/* 2. If the graph has flags, we push the previous flag value when */
/* traversing a flag-modifying arc. This is because a flag may */
/* may have been set during the previous "run" and may not apply. */
/* Since we're doing a DFS, we can be sure to return to the previous */
/* global flag state by just remembering that last flag change. */
/* If called with NULL as the input word, this will be set */
if (h->iterate_old == 1) {
goto resume;
}
h->ptr = 0; h->ipos = 0; h->opos = 0;
apply_stack_clear(h);
if (h->has_flags) {
apply_clear_flags(h);
}
/* "The use of four-letter words like goto can occasionally be justified */
/* even in the best of company." Knuth (1974). */
goto L2;
while(!apply_stack_isempty(h)) {
apply_stack_pop(h);
/* Last line */
if ((h->gstates+h->ptr)->state_no != (h->gstates+h->ptr+1)->state_no) {
/* Restore mark */
*(h->marks+(h->gstates+h->ptr)->state_no) = 0;
continue;
}
(h->ptr)++;
/* Follow arc & push old position */
L1:
for (f=0,h->curr_ptr = h->ptr; (h->gstates+h->curr_ptr)->state_no == (h->gstates+h->ptr)->state_no && (h->gstates+h->curr_ptr)-> in != -1; (h->curr_ptr)++) {
f = 0;
/* Select one random arc to follow out of all outgoing arcs */
if ((h->mode & RANDOM) == RANDOM) {
vcount = 0;
for (h->curr_ptr = h->ptr; (h->gstates+h->curr_ptr)->state_no == (h->gstates+h->ptr)->state_no && (h->gstates+h->curr_ptr)-> in != -1; (h->curr_ptr)++) {
vcount++;
}
if (vcount > 0) {
h->curr_ptr = h->ptr + (rand() % vcount) ;
} else {
h->curr_ptr = h->ptr;
}
}
symin = (((h->mode)&DOWN) == DOWN) ? (h->gstates+h->curr_ptr)->in : (h->gstates+h->curr_ptr)->out;
symout = (((h->mode)&DOWN) == DOWN) ? (h->gstates+h->curr_ptr)->out : (h->gstates+h->curr_ptr)->in;
msource = *(h->marks+(h->gstates+h->ptr)->state_no);
mtarget = *(h->marks+(h->gstates+(*(h->statemap+(h->gstates+h->curr_ptr)->target)))->state_no);
if (((eatupi = apply_match_str(h, symin, h->ipos)) != -1) && -1-(h->ipos)-eatupi != mtarget) {
eatupo = apply_append(h, h->curr_ptr, symout);
if (g_obey_flags && h->has_flags && ((h->flag_lookup+symin)->type & (FLAG_UNIFY|FLAG_CLEAR|FLAG_POSITIVE|FLAG_NEGATIVE))) {
fname = (h->flag_lookup+symin)->name;
fvalue = h->oldflagvalue;
fneg = h->oldflagneg;
} else {
fname = fvalue = NULL;
fneg = 0;
}
apply_stack_push(h, h->curr_ptr, h->ipos, h->opos, msource, fname, fvalue, fneg);
f = 1;
h->ptr = *(h->statemap+(h->gstates+h->curr_ptr)->target);
h->ipos = (h->ipos)+eatupi;
h->opos = (h->opos)+eatupo;
break;
}
}
/* There were no more edges on this vertex? */
if (!f) {
/* Unmark? */
*(h->marks+(h->gstates+h->ptr)->state_no) = 0;
continue;
}
/* Print accumulated string */
L2:
if ((h->gstates+h->ptr)->final_state == 1 && ((((h->mode) & ENUMERATE) == ENUMERATE) || (h->ipos == h->current_instring_length))) {
/* Stick a 0 to endpos to avoid getting old accumulated gunk strings printed */
*(h->outstring+h->opos) = '\0';
if (((h->mode) & RANDOM) == RANDOM) {
/* To end or not to end */
if (!(rand() % 2)) {
apply_stack_clear(h);
h->iterator = 0;
h->iterate_old = 0;
return(h->outstring);
}
} else {
return(h->outstring);
}
}
resume:
/* Mark */
/* 0 = unseen, +ipos = seen at ipos, -ipos = seen second time at ipos */
if ((h->mode & RANDOM) != RANDOM) {
if (*(h->marks+(h->gstates+h->ptr)->state_no) == h->ipos+1) {
*(h->marks+(h->gstates+h->ptr)->state_no) = -(h->ipos+1);
} else {
*(h->marks+(h->gstates+h->ptr)->state_no) = h->ipos+1;
}
}
goto L1;
}
/* Catch unprinted random which didn't stop at a final state */
if ((h->mode & RANDOM) == RANDOM) {
apply_stack_clear(h);
h->iterator = 0;
h->iterate_old = 0;
return(h->outstring);
}
apply_stack_clear(h);
return NULL;
}
char *apply_net(struct apply_handle *h) {
/* We perform a basic DFS on the graph, with two minor complications: */
/* 1. We keep a mark for each state which indicates how many input symbols */
/* we had consumed the last time we entered that state on the current */
/* "run." If we reach a state seen twice without consuming input, we */
/* terminate that branch of the search. */
/* As we pop a position, we also unmark the state we came from. */
/* 2. If the graph has flags, we push the previous flag value when */
/* traversing a flag-modifying arc (P,U,N, or C). This is because a */
/* flag may have been set during the previous "run" and may not apply. */
/* Since we're doing a DFS, we can be sure to return to the previous */
/* global flag state by just remembering that last flag change. */
/* 3. The whole system needs to work as an iterator, meaning we need to */
/* store the global state of the search so we can resume it later to */
/* to yield more possible output words with the same input string. */
char *returnstring;
if (h->iterate_old == 1) { /* If called with NULL as the input word, this will be set */
goto resume;
}
h->iptr = NULL; h->ptr = 0; h->ipos = 0; h->opos = 0;
apply_set_iptr(h);
apply_stack_clear(h);
if (h->has_flags) {
apply_clear_flags(h);
}
/* "The use of four-letter words like goto can occasionally be justified */
/* even in the best of company." Knuth (1974). */
goto L2;
while(!apply_stack_isempty(h)) {
apply_stack_pop(h);
/* If last line was popped */
if (apply_at_last_arc(h)) {
*(h->marks+(h->gstates+h->ptr)->state_no) = 0; /* Unmark */
continue; /* pop next */
}
apply_skip_this_arc(h); /* skip old pushed arc */
L1:
if (!apply_follow_next_arc(h)) {
*(h->marks+(h->gstates+h->ptr)->state_no) = 0; /* Unmark */
continue; /* pop next */
}
L2:
/* Print accumulated string upon entry to state */
if ((h->gstates+h->ptr)->final_state == 1 && (h->ipos == h->current_instring_length || ((h->mode) & ENUMERATE) == ENUMERATE)) {
if ((returnstring = (apply_return_string(h))) != NULL) {
return(returnstring);
}
}
resume:
apply_mark_state(h); /* Mark upon arrival to new state */
goto L1;
}
if ((h->mode & RANDOM) == RANDOM) {
apply_stack_clear(h);
h->iterator = 0;
h->iterate_old = 0;
return(h->outstring);
}
apply_stack_clear(h);
return NULL;
}