static void *GetPrevious(Iterator *it)
{
struct DequeIterator *li = (struct DequeIterator *)it;
Deque *L = li->D;
DequeNode rvp;
size_t i;
if (li->index >= L->count || li->index == 0)
return NULL;
if (li->timestamp != L->timestamp) {
L->RaiseError("GetNext",CONTAINER_ERROR_OBJECT_CHANGED);
return NULL;
}
rvp = L->head;
i=0;
li->index--;
if (li->index > 0) {
while (rvp != NULL && i < li->index) {
rvp = rvp->Next;
i++;
}
}
if (rvp == NULL) return NULL;
li->Current = rvp;
return rvp->Data;
}
static void *GetFirst(Iterator *it)
{
struct DequeIterator *li = (struct DequeIterator *)it;
Deque *L = li->D;
if (L->count == 0)
return NULL;
if (li->timestamp != L->timestamp) {
L->RaiseError("GetNext",CONTAINER_ERROR_OBJECT_CHANGED);
return NULL;
}
li->index = 0;
li->Current = L->head;
return L->head->Data;
}
static void *GetNext(Iterator *it)
{
struct DequeIterator *li = (struct DequeIterator *)it;
Deque *D = li->D;
void *result;
if (li->index >= (D->count-1) || li->Current == NULL)
return NULL;
if (li->timestamp != D->timestamp) {
D->RaiseError("GetNext",CONTAINER_ERROR_OBJECT_CHANGED);
return NULL;
}
li->Current = li->Current->Next;
li->index++;
result = li->Current->Data;
return result;
}
