void gc_collect(pobject env)
{
int collected = 0;
/*
int old_count = gc_objects;
*/
pobject prev, cur, object;
/* set gc flag of all gc_list objects to 0 */
cur = gc_list;
while (cur) {
gc_flag_set(cons_car(cur), 0);
cur = cons_cdr(cur);
}
/* traverse environment and set gc flag of all objects to 1 */
gc_traverse(env);
/* go through gc_list a second time and free all all objects
* with flag 0 */
prev = NIL;
cur = gc_list;
while (cur) {
object = cons_car(cur);
if (gc_flag_get(object) == 0) {
gc_free(object);
collected++;
if (prev) {
cons_cdr_set(prev, cons_cdr(cur));
object_free(cur);
cur = cons_cdr(prev);
} else {
gc_list = cons_cdr(cur);
object_free(cur);
cur = gc_list;
}
} else {
prev = cur;
cur = cons_cdr(cur);
}
}
/*
printf("\ngc_collect: %d of %d objects collected\n", collected, old_count);
*/
}
void gc_free(pobject object)
{
pobject prev = NIL, cur;
/* look for the cons cell in gc_list for object */
cur = gc_list;
while (cur) {
if (cons_car(cur) == object)
break;
prev = cur;
cur = cons_cdr(cur);
}
/* set new gc_list connections and free the cur cons cell */
if (cur) {
if (prev)
cons_cdr_set(prev, cons_cdr(cur));
else
gc_list = cons_cdr(cur);
object_free(cur);
}
object_free(object);
}
