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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection
package mutable
import generic._
import Math.MAX_INT
import TraversableView.NoBuilder
/** A non-strict view of a mutable vector.
* This is a leaf class which mixes methods returning a plain vector view
* and methods returning a mutable vector view.
* There is no associated `Like' class.
* @author Sean McDirmid
* @author Martin Odersky
* @version 2.8
* @since 2.8
*/
trait VectorView[A, +Coll] extends scala.collection.VectorView[A, Coll] {
self =>
def update(idx: Int, elem: A)
trait Transformed[B] extends VectorView[B, Coll] with super.Transformed[B] {
def update(idx: Int, elem: B)
}
trait Sliced extends Transformed[A] with super.Sliced {
override def update(idx: Int, elem: A) =
if (idx + from < until) self.update(idx + from, elem)
else throw new IndexOutOfBoundsException(idx.toString)
override def slice(from1: Int, until1: Int): Transformed[A] =
newSliced(from1 max 0, until1 max 0)
}
trait Filtered extends Transformed[A] with super.Filtered {
override def update(idx: Int, elem: A) = self.update(index(idx), elem)
}
trait TakenWhile extends Transformed[A] with super.TakenWhile {
override def update(idx: Int, elem: A) =
if (idx < len) self.update(idx, elem)
else throw new IndexOutOfBoundsException(idx.toString)
}
trait DroppedWhile extends Transformed[A] with super.DroppedWhile {
override def update(idx: Int, elem: A) =
if (idx >= 0) self.update(idx + start, elem)
else throw new IndexOutOfBoundsException(idx.toString)
}
trait Reversed extends Transformed[A] with super.Reversed {
override def update(idx: Int, elem: A) = self.update(length - 1 - idx, elem)
}
/** Boilerplate method, to override in each subclass
* This method could be eliminated if Scala had virtual classes
*/
protected override def newFiltered(p: A => Boolean): Transformed[A] = new Filtered { val pred = p }
protected override def newSliced(_from: Int, _until: Int): Transformed[A] = new Sliced { val from = _from; val until = _until }
protected override def newDroppedWhile(p: A => Boolean): Transformed[A] = new DroppedWhile { val pred = p }
protected override def newTakenWhile(p: A => Boolean): Transformed[A] = new TakenWhile { val pred = p }
protected override def newReversed: Transformed[A] = new Reversed { }
// Todo: if we replace VectorView[A, Coll] below by
// private[this] type This = VectorView[A, Coll]
// The interpreter will display resX.This.
// It shouldn't.
override def filter(p: A => Boolean): VectorView[A, Coll] = newFiltered(p)
override def init: VectorView[A, Coll] = newSliced(0, size - 1).asInstanceOf[VectorView[A, Coll]]
override def drop(n: Int): VectorView[A, Coll] = newSliced(n max 0, MAX_INT).asInstanceOf[VectorView[A, Coll]]
override def take(n: Int): VectorView[A, Coll] = newSliced(0, n).asInstanceOf[VectorView[A, Coll]]
override def slice(from: Int, until: Int): VectorView[A, Coll] = newSliced(from max 0, until).asInstanceOf[VectorView[A, Coll]]
override def dropWhile(p: A => Boolean): VectorView[A, Coll] = newDroppedWhile(p).asInstanceOf[VectorView[A, Coll]]
override def takeWhile(p: A => Boolean): VectorView[A, Coll] = newTakenWhile(p).asInstanceOf[VectorView[A, Coll]]
override def span(p: A => Boolean): (VectorView[A, Coll], VectorView[A, Coll]) = (takeWhile(p), dropWhile(p))
override def splitAt(n: Int): (VectorView[A, Coll], VectorView[A, Coll]) = (take(n), drop(n))
override def reverse: VectorView[A, Coll] = newReversed.asInstanceOf[VectorView[A, Coll]]
}
/*
* object VectorView {
type Coll = TraversableView[_, C] forSome { type C <: scala.collection.Traversable[_] }
implicit def canBuildFrom[A]: CanBuildFrom[Vector[_], A, VectorView[A], Coll] = new CanBuildFrom[mutable.Vector[_], A, VectorView[A], Coll] { : Coll) = new NoBuilder }
}
*/
|
