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| author | Erik Rozendaal <erik@deler.org> | 2012-01-02 16:49:29 +0100 |
|---|---|---|
| committer | Erik Rozendaal <erik@deler.org> | 2012-01-02 16:49:29 +0100 |
| commit | 3dea25186670096b25150baba981eb36ef244a5f (patch) | |
| tree | d6cde37bd4821a1b3bbcdb42ed737aed99b8dbac /src/library | |
| parent | 82374ad4c2c518ef8ee3fe3d2ef3e72cce75d4f1 (diff) | |
| download | scala-3dea25186670096b25150baba981eb36ef244a5f.tar.gz scala-3dea25186670096b25150baba981eb36ef244a5f.tar.bz2 scala-3dea25186670096b25150baba981eb36ef244a5f.zip | |
Implemented range without using pattern matching.
Diffstat (limited to 'src/library')
| -rw-r--r-- | src/library/scala/collection/immutable/RedBlack.scala | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/src/library/scala/collection/immutable/RedBlack.scala b/src/library/scala/collection/immutable/RedBlack.scala index 57b08c2b8c..3b16f719bf 100644 --- a/src/library/scala/collection/immutable/RedBlack.scala +++ b/src/library/scala/collection/immutable/RedBlack.scala @@ -224,23 +224,28 @@ object RedBlack { right: Tree[A, B], leftZipper: List[NonEmpty[A, B]], rightZipper: List[NonEmpty[A, B]], - smallerDepth: Int): (List[NonEmpty[A, B]], Boolean, Boolean, Int) = (left, right) match { - case (l @ BlackTree(_, _, _, _), r @ BlackTree(_, _, _, _)) => + smallerDepth: Int): (List[NonEmpty[A, B]], Boolean, Boolean, Int) = { + lazy val l = left.asInstanceOf[NonEmpty[A, B]] + lazy val r = right.asInstanceOf[NonEmpty[A, B]] + if (isBlackTree(left) && isBlackTree(right)) { unzipBoth(l.right, r.left, l :: leftZipper, r :: rightZipper, smallerDepth + 1) - case (l @ RedTree(_, _, _, _), r @ RedTree(_, _, _, _)) => + } else if (isRedTree(left) && isRedTree(right)) { unzipBoth(l.right, r.left, l :: leftZipper, r :: rightZipper, smallerDepth) - case (_, r @ RedTree(_, _, _, _)) => + } else if (isRedTree(right)) { unzipBoth(left, r.left, leftZipper, r :: rightZipper, smallerDepth) - case (l @ RedTree(_, _, _, _), _) => + } else if (isRedTree(left)) { unzipBoth(l.right, right, l :: leftZipper, rightZipper, smallerDepth) - case (Empty.Instance, Empty.Instance) => + } else if ((left eq Empty.Instance) && (right eq Empty.Instance)) { (Nil, true, false, smallerDepth) - case (Empty.Instance, r @ BlackTree(_, _, _, _)) => + } else if ((left eq Empty.Instance) && isBlackTree(right)) { val leftMost = true (unzip(r :: rightZipper, leftMost), false, leftMost, smallerDepth) - case (l @ BlackTree(_, _, _, _), Empty.Instance) => + } else if (isBlackTree(left) && (right eq Empty.Instance)) { val leftMost = false (unzip(l :: leftZipper, leftMost), false, leftMost, smallerDepth) + } else { + sys.error("unmatched trees in unzip: " + left + ", " + right) + } } unzipBoth(left, right, Nil, Nil, 0) } @@ -248,7 +253,7 @@ object RedBlack { private[this] def rebalance(newLeft: Tree[A, B], newRight: Tree[A, B]) = { // This is like drop(n-1), but only counting black nodes def findDepth(zipper: List[NonEmpty[A, B]], depth: Int): List[NonEmpty[A, B]] = zipper match { - case BlackTree(_, _, _, _) :: tail => + case head :: tail if isBlackTree(head) => if (depth == 1) zipper else findDepth(tail, depth - 1) case _ :: tail => findDepth(tail, depth) case Nil => sys.error("Defect: unexpected empty zipper while computing range") |