diff options
author | Simon Ochsenreither <simon@ochsenreither.de> | 2013-12-10 00:47:59 +0100 |
---|---|---|
committer | Simon Ochsenreither <simon@ochsenreither.de> | 2013-12-11 21:50:09 +0100 |
commit | f0f0a5e7813501d985174d3c5573c34c8a7608c6 (patch) | |
tree | eb3d6cd0f03ef7c5c579a53c5f7445ba5b1b9c2c | |
parent | b345b42cac64aa97e3bbcc6f14ef8f08214ab56f (diff) | |
download | scala-f0f0a5e7813501d985174d3c5573c34c8a7608c6.tar.gz scala-f0f0a5e7813501d985174d3c5573c34c8a7608c6.tar.bz2 scala-f0f0a5e7813501d985174d3c5573c34c8a7608c6.zip |
SI-8059 Override immutable.Queue#{+:,:+} for performance
Without those overrides, all elements are unnecessarily copied.
-rw-r--r-- | src/library/scala/collection/immutable/Queue.scala | 12 | ||||
-rw-r--r-- | test/files/run/iq.check | 4 | ||||
-rw-r--r-- | test/files/run/iq.scala | 17 |
3 files changed, 29 insertions, 4 deletions
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. diff --git a/test/files/run/iq.check b/test/files/run/iq.check index 81114ea181..311bf83ed4 100644 --- a/test/files/run/iq.check +++ b/test/files/run/iq.check @@ -1,4 +1,8 @@ Empty +q2: Queue(42, 0) +qa: Queue(42, 0) +qb: Queue(42, 0) +qc: Queue(42, 0) Head: 42 q5: Queue(0, 1, 2, 3, 4, 5, 6, 7, 8, 9) q5[5]: 5 diff --git a/test/files/run/iq.scala b/test/files/run/iq.scala index 31859cf867..1eb1d40e37 100644 --- a/test/files/run/iq.scala +++ b/test/files/run/iq.scala @@ -16,10 +16,21 @@ object iq { Console.println("Empty") } - /* Test infix enqueing. */ - //val q2 = q + 42 + 0 // deprecated + /* Test enqueing. */ val q2 = q.enqueue(42).enqueue(0) + val qa = q :+ 42 :+ 0 + assert(q2 == qa) + + val qb = 42 +: 0 +: q + assert(q2 == qb) + val qc = 42 +: q :+ 0 + assert(q2 == qc) + Console.println("q2: " + q2) + Console.println("qa: " + qa) + Console.println("qb: " + qb) + Console.println("qc: " + qc) + /* Test is empty and dequeue. * Expected: Head: 42 */ @@ -37,7 +48,7 @@ object iq { /* Test sequence enqueing. */ val q5: Queue[Any] = q4.enqueue(List(1,2,3,4,5,6,7,8,9)) /* Test toString. - * Expected: Head: q5: Queue(0,1,2,3,4,5,6,7,8,9) + * Expected: q5: Queue(0,1,2,3,4,5,6,7,8,9) */ Console.println("q5: " + q5) /* Test apply |