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Queue now uses a freelist to minimize allocations.

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This commit is contained in:
Ferdinand Majerech 2014-08-04 02:16:34 +02:00
parent 1f55fccc26
commit 063d9754d7
1 changed files with 30 additions and 7 deletions
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37
source/dyaml/queue.d
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@ -45,6 +45,10 @@ struct Queue(T)
Node* last_ = null;
/// Cursor pointing to the current node in iteration.
Node* cursor_ = null;
/// The first element of a linked list of freed Nodes available for recycling.
Node* freeList_ = null;
/// Length of the queue.
size_t length_ = 0;
@ -54,9 +58,15 @@ struct Queue(T)
@disable int opCmp(ref Queue);
/// Destroy the queue, deallocating all its elements.
@safe nothrow ~this()
@trusted nothrow ~this()
{
while(!empty) { pop(); }
while(freeList_ !is null)
{
auto toFree = freeList_;
freeList_ = toFree.next_;
free(toFree);
}
cursor_ = last_ = first_ = null;
length_ = 0;
}
@ -90,9 +100,19 @@ struct Queue(T)
/// Push new item to the queue.
void push(T item) @trusted nothrow
{
Node* newLast = allocate!Node(item, cast(Node*)null);
Node* newLast;
if(freeList_ !is null)
{
newLast = freeList_;
freeList_ = freeList_.next_;
*newLast = Node(item, null);
}
else
{
newLast = allocate!Node(item, cast(Node*)null);
}
if(last_ !is null) { last_.next_ = newLast; }
if(first_ is null) { first_ = newLast; }
if(first_ is null) { first_ = newLast; }
last_ = newLast;
++length_;
}
@ -139,10 +159,13 @@ struct Queue(T)
}
body
{
T result = peek();
Node* temp = first_;
first_ = first_.next_;
free(temp);
T result = peek();
Node* popped = first_;
first_ = first_.next_;
Node* oldFree = freeList_;
freeList_ = popped;
freeList_.next_ = oldFree;
if(--length_ == 0)
{
assert(first_ is null);