diff options
Diffstat (limited to 'src/library/scala/collection/immutable/Stream.scala')
-rw-r--r-- | src/library/scala/collection/immutable/Stream.scala | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/src/library/scala/collection/immutable/Stream.scala b/src/library/scala/collection/immutable/Stream.scala index 91a4e1c43d..714d5117d3 100644 --- a/src/library/scala/collection/immutable/Stream.scala +++ b/src/library/scala/collection/immutable/Stream.scala @@ -499,16 +499,6 @@ self => ) else super.flatMap(f)(bf) - override private[scala] def filterImpl(p: A => Boolean, isFlipped: Boolean): Stream[A] = { - // optimization: drop leading prefix of elems for which f returns false - // var rest = this dropWhile (!p(_)) - forget DRY principle - GC can't collect otherwise - var rest = this - while (!rest.isEmpty && p(rest.head) == isFlipped) rest = rest.tail - // private utility func to avoid `this` on stack (would be needed for the lazy arg) - if (rest.nonEmpty) Stream.filteredTail(rest, p, isFlipped) - else Stream.Empty - } - /** Returns all the elements of this `Stream` that satisfy the predicate `p` * in a new `Stream` - i.e., it is still a lazy data structure. The order of * the elements is preserved @@ -522,7 +512,15 @@ self => * // produces * }}} */ - override def filter(p: A => Boolean): Stream[A] = filterImpl(p, isFlipped = false) // This override is only left in 2.11 because of binary compatibility, see PR #3925 + override def filter(p: A => Boolean): Stream[A] = { + // optimization: drop leading prefix of elems for which f returns false + // var rest = this dropWhile (!p(_)) - forget DRY principle - GC can't collect otherwise + var rest = this + while (!rest.isEmpty && !p(rest.head)) rest = rest.tail + // private utility func to avoid `this` on stack (would be needed for the lazy arg) + if (rest.nonEmpty) Stream.filteredTail(rest, p) + else Stream.Empty + } override final def withFilter(p: A => Boolean): StreamWithFilter = new StreamWithFilter(p) @@ -1286,8 +1284,8 @@ object Stream extends SeqFactory[Stream] { else cons(start, range(start + step, end, step)) } - private[immutable] def filteredTail[A](stream: Stream[A], p: A => Boolean, isFlipped: Boolean) = { - cons(stream.head, stream.tail.filterImpl(p, isFlipped)) + private[immutable] def filteredTail[A](stream: Stream[A], p: A => Boolean) = { + cons(stream.head, stream.tail filter p) } private[immutable] def collectedTail[A, B, That](head: B, stream: Stream[A], pf: PartialFunction[A, B], bf: CanBuildFrom[Stream[A], B, That]) = { |