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#include "gc.h"
#include "exc.h"
#include "consts.h"
#ifdef GC_DEBUG
#include <cstdio>
typedef unsigned long long ull;
#endif
static EvalObj *gcq[GC_QUEUE_SIZE];
GarbageCollector::GarbageCollector() {
mapping.clear();
pend_cnt = 0;
pending_list = NULL;
}
GarbageCollector::PendingEntry::PendingEntry(
EvalObj *_obj, PendingEntry *_next) : obj(_obj), next(_next) {}
void GarbageCollector::expose(EvalObj *ptr, bool delay) {
bool flag = mapping.count(ptr);
if (flag)
{
if (!--mapping[ptr] && !delay)
{
#ifdef GC_DEBUG
fprintf(stderr, "GC: 0x%llx pending. \n", (ull)ptr);
#endif
pending_list = new PendingEntry(ptr, pending_list);
if (++pend_cnt == GC_QUEUE_SIZE >> 1)
force(); // the gc queue may overflow
}
}
}
void GarbageCollector::force() {
EvalObj **l = gcq, **r = l;
for (PendingEntry *p = pending_list, *np; p; p = np)
{
np = p->next;
*r++ = p->obj;
delete p;
} // fetch the pending pointers in the list
// clear the list
pending_list = NULL;
#ifdef GC_DEBUG
size_t cnt = 0;
fprintf(stderr, "GC: Forcing the clear process...\n");
#endif
for (; l != r; l++)
{
#ifdef GC_DEBUG
fprintf(stderr, "GC: destroying space 0x%llx. \n", (ull)*l);
cnt++;
#endif
delete *l;
// maybe it's a complex structure,
// so that more pointers are reported
for (PendingEntry *p = pending_list, *np; p; p = np)
{
np = p->next;
*r++ = p->obj;
if (r == gcq + GC_QUEUE_SIZE)
throw NormalError(RUN_ERR_GC_OVERFLOW);
delete p;
}
pending_list = NULL;
}
#ifdef GC_DEBUG
fprintf(stderr, "GC: Forced clear, %lu objects are freed\n", cnt);
#endif
}
EvalObj *GarbageCollector::attach(EvalObj *ptr) {
if (!ptr) return NULL; // NULL pointer
bool flag = mapping.count(ptr);
if (flag) mapping[ptr]++;
else mapping[ptr] = 1;
#ifdef GC_DEBUG
fprintf(stderr, "GC: 0x%llx attached. count = %lu \"%s\"\n",
(ull)ptr, mapping[ptr], ptr->ext_repr().c_str());
#endif
return ptr; // passing through
}
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