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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
package mutable
import generic._
/** This class is used internally to implement data structures that
* are based on resizable arrays.
*
* @tparam A type of the elements contained in this resizable array.
*
* @author Matthias Zenger, Burak Emir
* @author Martin Odersky
* @version 2.8
* @since 1
*/
trait ResizableArray[A] extends IndexedSeq[A]
with GenericTraversableTemplate[A, ResizableArray]
with IndexedSeqOptimized[A, ResizableArray[A]] {
override def companion: GenericCompanion[ResizableArray] = ResizableArray
protected def initialSize: Int = 16
protected var array: Array[AnyRef] = new Array[AnyRef](math.max(initialSize, 1))
protected var size0: Int = 0
//##########################################################################
// implement/override methods of IndexedSeq[A]
/** Returns the length of this resizable array.
*/
def length: Int = size0
def apply(idx: Int) = {
if (idx >= size0) throw new IndexOutOfBoundsException(idx.toString)
array(idx).asInstanceOf[A]
}
def update(idx: Int, elem: A) {
if (idx >= size0) throw new IndexOutOfBoundsException(idx.toString)
array(idx) = elem.asInstanceOf[AnyRef]
}
override def foreach[U](f: A => U) {
var i = 0
// size is cached here because profiling reports a lot of time spent calling
// it on every iteration. I think it's likely a profiler ghost but it doesn't
// hurt to lift it into a local.
val top = size
while (i < top) {
f(array(i).asInstanceOf[A])
i += 1
}
}
/** Fills the given array `xs` with at most `len` elements of this
* traversable starting at position `start`.
*
* Copying will stop once either the end of the current traversable is
* reached or `len` elements have been copied or the end of the array
* is reached.
*
* @param xs the array to fill.
* @param start starting index.
* @param len number of elements to copy
*/
override def copyToArray[B >: A](xs: Array[B], start: Int, len: Int) {
val len1 = len min (xs.length - start) min length
if (len1 > 0) Array.copy(array, 0, xs, start, len1)
}
//##########################################################################
/** Remove elements of this array at indices after `sz`.
*/
def reduceToSize(sz: Int) {
require(sz <= size0)
while (size0 > sz) {
size0 -= 1
array(size0) = null
}
}
/** Ensure that the internal array has at least `n` cells. */
protected def ensureSize(n: Int) {
// Use a Long to prevent overflows
val arrayLength: Long = array.length
if (n > arrayLength) {
var newSize: Long = arrayLength * 2
while (n > newSize)
newSize = newSize * 2
// Clamp newSize to Int.MaxValue
if (newSize > Int.MaxValue) newSize = Int.MaxValue
val newArray: Array[AnyRef] = new Array(newSize.toInt)
java.lang.System.arraycopy(array, 0, newArray, 0, size0)
array = newArray
}
}
/** Swap two elements of this array.
*/
protected def swap(a: Int, b: Int) {
val h = array(a)
array(a) = array(b)
array(b) = h
}
/** Move parts of the array.
*/
protected def copy(m: Int, n: Int, len: Int) {
scala.compat.Platform.arraycopy(array, m, array, n, len)
}
}
object ResizableArray extends SeqFactory[ResizableArray] {
implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, ResizableArray[A]] =
ReusableCBF.asInstanceOf[GenericCanBuildFrom[A]]
def newBuilder[A]: Builder[A, ResizableArray[A]] = new ArrayBuffer[A]
}
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