void FreeList::getFirstNChunksFromList(size_t n, FreeList* fl) {
assert_proper_lock_protection();
assert(fl->count() == 0, "Precondition");
if (count() > 0) {
int k = 1;
fl->set_head(head());
n--;
FreeChunk* tl = head();
while (tl->next() != NULL && n > 0) {
tl = tl->next();
n--;
k++;
}
assert(tl != NULL, "Loop Inv.");
// First, fix up the list we took from.
FreeChunk* new_head = tl->next();
set_head(new_head);
set_count(count() - k);
if (new_head == NULL) {
set_tail(NULL);
} else {
new_head->linkPrev(NULL);
}
// Now we can fix up the tail.
tl->linkNext(NULL);
// And return the result.
fl->set_tail(tl);
fl->set_count(k);
}
}
// Remove this chunk from the list
void FreeList::removeChunk(FreeChunk*fc) {
assert_proper_lock_protection();
assert(head() != NULL, "Remove from empty list");
assert(fc != NULL, "Remove a NULL chunk");
assert(size() == fc->size(), "Wrong list");
assert(head() == NULL || head()->prev() == NULL, "list invariant");
assert(tail() == NULL || tail()->next() == NULL, "list invariant");
FreeChunk* prevFC = fc->prev();
FreeChunk* nextFC = fc->next();
if (nextFC != NULL) {
// The chunk fc being removed has a "next". Set the "next" to the
// "prev" of fc.
nextFC->linkPrev(prevFC);
} else { // removed tail of list
link_tail(prevFC);
}
if (prevFC == NULL) { // removed head of list
link_head(nextFC);
assert(nextFC == NULL || nextFC->prev() == NULL,
"Prev of head should be NULL");
} else {
prevFC->linkNext(nextFC);
assert(tail() != prevFC || prevFC->next() == NULL,
"Next of tail should be NULL");
}
decrement_count();
assert(((head() == NULL) + (tail() == NULL) + (count() == 0)) % 3 == 0,
"H/T/C Inconsistency");
// clear next and prev fields of fc, debug only
NOT_PRODUCT(
fc->linkPrev(NULL);
fc->linkNext(NULL);
)
