pekko/docs/scaladocs-akka-actors/stm/Vector.scala.html

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/**
Copyright (c) 2007-2008, Rich Hickey
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
* Neither the name of Clojure nor the names of its contributors
may be used to endorse or promote products derived from this
software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
**/
package se.scalablesolutions.akka.collection
import Vector._
/**
* A straight port of Clojure's &lt;code>PersistentVector&lt;/code> class.
*
* @author Daniel Spiewak
* @author Rich Hickey
*/
@serializable
class Vector[+T] private (val length: Int, shift: Int, root: Array[AnyRef], tail: Array[AnyRef])
extends RandomAccessSeq[T] with PersistentDataStructure { outer =>
private val tailOff = length - tail.length
/*
* The design of this data structure inherantly requires heterogenous arrays.
* It is *possible* to design around this, but the result is comparatively
* quite inefficient. With respect to this fact, I have left the original
* (somewhat dynamically-typed) implementation in place.
*/
private[collection] def this() = this(0, 5, EmptyArray, EmptyArray)
def apply(i: Int): T = {
if (i >= 0 && i &lt; length) {
if (i >= tailOff) {
tail(i & 0x01f).asInstanceOf[T]
} else {
var arr = root
var level = shift
while (level > 0) {
arr = arr((i >>> level) & 0x01f).asInstanceOf[Array[AnyRef]]
level -= 5
}
arr(i & 0x01f).asInstanceOf[T]
}
} else throw new IndexOutOfBoundsException(i.toString)
}
def update[A >: T](i: Int, obj: A): Vector[A] = {
if (i >= 0 && i &lt; length) {
if (i >= tailOff) {
val newTail = new Array[AnyRef](tail.length)
Array.copy(tail, 0, newTail, 0, tail.length)
newTail(i & 0x01f) = obj.asInstanceOf[AnyRef]
new Vector[A](length, shift, root, newTail)
} else {
new Vector[A](length, shift, doAssoc(shift, root, i, obj), tail)
}
} else if (i == length) {
this + obj
} else throw new IndexOutOfBoundsException(i.toString)
}
private def doAssoc[A >: T](level: Int, arr: Array[AnyRef], i: Int, obj: A): Array[AnyRef] = {
val ret = new Array[AnyRef](arr.length)
Array.copy(arr, 0, ret, 0, arr.length)
if (level == 0) {
ret(i & 0x01f) = obj.asInstanceOf[AnyRef]
} else {
val subidx = (i >>> level) & 0x01f
ret(subidx) = doAssoc(level - 5, arr(subidx).asInstanceOf[Array[AnyRef]], i, obj)
}
ret
}
override def ++[A >: T](other: Iterable[A]) = other.foldLeft(this:Vector[A]) { _ + _ }
def +[A >: T](obj: A): Vector[A] = {
if (tail.length &lt; 32) {
val newTail = new Array[AnyRef](tail.length + 1)
Array.copy(tail, 0, newTail, 0, tail.length)
newTail(tail.length) = obj.asInstanceOf[AnyRef]
new Vector[A](length + 1, shift, root, newTail)
} else {
var (newRoot, expansion) = pushTail(shift - 5, root, tail, null)
var newShift = shift
2009-12-27 08:24:11 +01:00
if (expansion ne null) {
newRoot = array(newRoot, expansion)
newShift += 5
}
new Vector[A](length + 1, newShift, newRoot, array(obj.asInstanceOf[AnyRef]))
}
}
private def pushTail(level: Int, arr: Array[AnyRef], tailNode: Array[AnyRef], expansion: AnyRef): (Array[AnyRef], AnyRef) = {
val newChild = if (level == 0) tailNode else {
val (newChild, subExpansion) = pushTail(level - 5, arr(arr.length - 1).asInstanceOf[Array[AnyRef]], tailNode, expansion)
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if (subExpansion eq null) {
val ret = new Array[AnyRef](arr.length)
Array.copy(arr, 0, ret, 0, arr.length)
ret(arr.length - 1) = newChild
return (ret, null)
} else subExpansion
}
// expansion
if (arr.length == 32) {
(arr, array(newChild))
} else {
val ret = new Array[AnyRef](arr.length + 1)
Array.copy(arr, 0, ret, 0, arr.length)
ret(arr.length) = newChild
(ret, null)
}
}
/**
* Removes the &lt;i>tail&lt;/i> element of this vector.
*/
def pop: Vector[T] = {
if (length == 0) {
throw new IllegalStateException("Can't pop empty vector")
} else if (length == 1) {
EmptyVector
} else if (tail.length > 1) {
val newTail = new Array[AnyRef](tail.length - 1)
Array.copy(tail, 0, newTail, 0, newTail.length)
new Vector[T](length - 1, shift, root, newTail)
} else {
var (newRoot, pTail) = popTail(shift - 5, root, null)
var newShift = shift
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if (newRoot eq null) {
newRoot = EmptyArray
}
if (shift > 5 && newRoot.length == 1) {
newRoot = newRoot(0).asInstanceOf[Array[AnyRef]]
newShift -= 5
}
new Vector[T](length - 1, newShift, newRoot, pTail.asInstanceOf[Array[AnyRef]])
}
}
private def popTail(shift: Int, arr: Array[AnyRef], pTail: AnyRef): (Array[AnyRef], AnyRef) = {
val newPTail = if (shift > 0) {
val (newChild, subPTail) = popTail(shift - 5, arr(arr.length - 1).asInstanceOf[Array[AnyRef]], pTail)
2009-12-27 08:24:11 +01:00
if (newChild ne null) {
val ret = new Array[AnyRef](arr.length)
Array.copy(arr, 0, ret, 0, arr.length)
ret(arr.length - 1) = newChild
return (ret, subPTail)
}
subPTail
} else if (shift == 0) {
arr(arr.length - 1)
} else pTail
// contraction
if (arr.length == 1) {
(null, newPTail)
} else {
val ret = new Array[AnyRef](arr.length - 1)
Array.copy(arr, 0, ret, 0, ret.length)
(ret, newPTail)
}
}
override def filter(p: (T)=>Boolean) = {
var back = new Vector[T]
var i = 0
while (i &lt; length) {
val e = apply(i)
if (p(e)) back += e
i += 1
}
back
}
override def flatMap[A](f: (T)=>Iterable[A]): Vector[A] = {
var back = new Vector[A]
var i = 0
while (i &lt; length) {
f(apply(i)) foreach { back += _ }
i += 1
}
back
}
override def map[A](f: (T)=>A): Vector[A] = {
var back = new Vector[A]
var i = 0
while (i &lt; length) {
back += f(apply(i))
i += 1
}
back
}
override def reverse: Vector[T] = new VectorProjection[T] {
override val length = outer.length
override def apply(i: Int) = outer.apply(length - i - 1)
}
override def subseq(from: Int, end: Int) = subVector(from, end)
def subVector(from: Int, end: Int): Vector[T] = {
if (from &lt; 0) {
throw new IndexOutOfBoundsException(from.toString)
} else if (end >= length) {
throw new IndexOutOfBoundsException(end.toString)
} else if (end &lt;= from) {
throw new IllegalArgumentException("Invalid range: " + from + ".." + end)
} else {
new VectorProjection[T] {
override val length = end - from
override def apply(i: Int) = outer.apply(i + from)
}
}
}
def zip[A](that: Vector[A]) = {
var back = new Vector[(T, A)]
var i = 0
val limit = Math.min(length, that.length)
while (i &lt; limit) {
back += (apply(i), that(i))
i += 1
}
back
}
def zipWithIndex = {
var back = new Vector[(T, Int)]
var i = 0
while (i &lt; length) {
back += (apply(i), i)
i += 1
}
back
}
override def equals(other: Any) = other match {
case vec: Vector[_] => {
var back = length == vec.length
var i = 0
while (i &lt; length) {
back &&= apply(i) == vec.apply(i)
i += 1
}
back
}
case _ => false
}
override def hashCode = foldLeft(0) { _ ^ _.hashCode }
}
object Vector {
private[collection] val EmptyArray = new Array[AnyRef](0)
def apply[T](elems: T*) = elems.foldLeft(EmptyVector:Vector[T]) { _ + _ }
def unapplySeq[T](vec: Vector[T]): Option[Seq[T]] = Some(vec)
@inline
private[collection] def array(elems: AnyRef*) = {
val back = new Array[AnyRef](elems.length)
Array.copy(elems, 0, back, 0, back.length)
back
}
}
object EmptyVector extends Vector[Nothing]
private[collection] abstract class VectorProjection[+T] extends Vector[T] {
override val length: Int
override def apply(i: Int): T
override def +[A >: T](e: A) = innerCopy + e
override def update[A >: T](i: Int, e: A) = {
if (i &lt; 0) {
throw new IndexOutOfBoundsException(i.toString)
} else if (i > length) {
throw new IndexOutOfBoundsException(i.toString)
} else innerCopy(i) = e
}
private lazy val innerCopy = foldLeft(EmptyVector:Vector[T]) { _ + _ }
}
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