From f0f0a5e7813501d985174d3c5573c34c8a7608c6 Mon Sep 17 00:00:00 2001 From: Simon Ochsenreither Date: Tue, 10 Dec 2013 00:47:59 +0100 Subject: SI-8059 Override immutable.Queue#{+:,:+} for performance Without those overrides, all elements are unnecessarily copied. --- src/library/scala/collection/immutable/Queue.scala | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'src/library') diff --git a/src/library/scala/collection/immutable/Queue.scala b/src/library/scala/collection/immutable/Queue.scala index df1484c4ab..264304db68 100644 --- a/src/library/scala/collection/immutable/Queue.scala +++ b/src/library/scala/collection/immutable/Queue.scala @@ -89,6 +89,16 @@ class Queue[+A] protected(protected val in: List[A], protected val out: List[A]) */ override def length = in.length + out.length + override def +:[B >: A, That](elem: B)(implicit bf: CanBuildFrom[Queue[A], B, That]): That = bf match { + case _: Queue.GenericCanBuildFrom[_] => new Queue(in, elem :: out).asInstanceOf[That] + case _ => super.+:(elem)(bf) + } + + override def :+[B >: A, That](elem: B)(implicit bf: CanBuildFrom[Queue[A], B, That]): That = bf match { + case _: Queue.GenericCanBuildFrom[_] => enqueue(elem).asInstanceOf[That] + case _ => super.:+(elem)(bf) + } + /** Creates a new queue with element added at the end * of the old queue. * @@ -118,7 +128,7 @@ class Queue[+A] protected(protected val in: List[A], protected val out: List[A]) case x :: xs => (x, new Queue(in, xs)) case _ => throw new NoSuchElementException("dequeue on empty queue") } - + /** Optionally retrieves the first element and a queue of the remaining elements. * * @return A tuple of the first element of the queue, and a new queue with this element removed. -- cgit v1.2.3