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package scala.collection.parallel.mutable
import scala.collection.generic.Sizing
import scala.collection.mutable.ArraySeq
import scala.collection.mutable.ArrayBuffer
import scala.collection.parallel.TaskSupport
import scala.collection.parallel.EnvironmentPassingCombiner
import scala.collection.parallel.unsupportedop
import scala.collection.parallel.UnrolledBuffer
import scala.collection.parallel.UnrolledBuffer.Unrolled
import scala.collection.parallel.Combiner
private[mutable] class DoublingUnrolledBuffer[T](implicit m: ClassManifest[T]) extends UnrolledBuffer[T]()(m) {
override def calcNextLength(sz: Int) = if (sz < 10000) sz * 2 else sz
protected override def newUnrolled = new Unrolled[T](0, new Array[T](4), null, this)
}
/** An array combiner that uses doubling unrolled buffers to store elements. */
trait UnrolledParArrayCombiner[T]
extends Combiner[T, ParArray[T]] {
self: EnvironmentPassingCombiner[T, ParArray[T]] =>
// because size is doubling, random access is O(logn)!
val buff = new DoublingUnrolledBuffer[Any]
import tasksupport._
def +=(elem: T) = {
buff += elem
this
}
def result = {
val arrayseq = new ArraySeq[T](size)
val array = arrayseq.array.asInstanceOf[Array[Any]]
executeAndWaitResult(new CopyUnrolledToArray(array, 0, size))
new ParArray(arrayseq)
}
def clear {
buff.clear
}
override def sizeHint(sz: Int) = {
buff.lastPtr.next = new Unrolled(0, new Array[Any](sz), null, buff)
buff.lastPtr = buff.lastPtr.next
}
def combine[N <: T, NewTo >: ParArray[T]](other: Combiner[N, NewTo]): Combiner[N, NewTo] = other match {
case that if that eq this => this // just return this
case that: UnrolledParArrayCombiner[t] =>
buff concat that.buff
this
case _ => unsupportedop("Cannot combine with combiner of different type.")
}
def size = buff.size
/* tasks */
class CopyUnrolledToArray(array: Array[Any], offset: Int, howmany: Int)
extends Task[Unit, CopyUnrolledToArray] {
var result = ();
def leaf(prev: Option[Unit]) = if (howmany > 0) {
var totalleft = howmany
val (startnode, startpos) = findStart(offset)
var curr = startnode
var pos = startpos
var arroffset = offset
while (totalleft > 0) {
val lefthere = math.min(totalleft, curr.size - pos)
Array.copy(curr.array, pos, array, arroffset, lefthere)
// println("from: " + arroffset + " elems " + lefthere + " - " + pos + ", " + curr + " -> " + array.toList + " by " + this + " !! " + buff.headPtr)
totalleft -= lefthere
arroffset += lefthere
pos = 0
curr = curr.next
}
}
private def findStart(pos: Int) = {
var left = pos
var node = buff.headPtr
while ((left - node.size) >= 0) {
left -= node.size
node = node.next
}
(node, left)
}
def split = {
val fp = howmany / 2
List(new CopyUnrolledToArray(array, offset, fp), new CopyUnrolledToArray(array, offset + fp, howmany - fp))
}
def shouldSplitFurther = howmany > collection.parallel.thresholdFromSize(size, parallelismLevel)
override def toString = "CopyUnrolledToArray(" + offset + ", " + howmany + ")"
}
}
object UnrolledParArrayCombiner {
def apply[T](): UnrolledParArrayCombiner[T] = new UnrolledParArrayCombiner[T] with EnvironmentPassingCombiner[T, ParArray[T]]
}
/** An array combiner that uses a chain of arraybuffers to store elements. */
trait ResizableParArrayCombiner[T]
extends LazyCombiner[T, ParArray[T], ExposedArrayBuffer[T]]
{
self: EnvironmentPassingCombiner[T, ParArray[T]] =>
import tasksupport._
override def sizeHint(sz: Int) = if (chain.length == 1) chain(0).sizeHint(sz)
def newLazyCombiner(c: ArrayBuffer[ExposedArrayBuffer[T]]) = ResizableParArrayCombiner(c)
def allocateAndCopy = if (chain.size > 1) {
val arrayseq = new ArraySeq[T](size)
val array = arrayseq.array.asInstanceOf[Array[Any]]
executeAndWaitResult(new CopyChainToArray(array, 0, size))
new ParArray(arrayseq)
} else { // optimisation if there is only 1 array
val pa = new ParArray(new ExposedArraySeq[T](chain(0).internalArray, size))
pa
}
override def toString = "ResizableParArrayCombiner(" + size + "): " //+ chain
/* tasks */
class CopyChainToArray(array: Array[Any], offset: Int, howmany: Int) extends Task[Unit, CopyChainToArray] {
var result = ()
def leaf(prev: Option[Unit]) = if (howmany > 0) {
var totalleft = howmany
val (stbuff, stind) = findStart(offset)
var buffind = stbuff
var ind = stind
var arrayIndex = offset
while (totalleft > 0) {
val currbuff = chain(buffind)
val chunksize = if (totalleft < (currbuff.size - ind)) totalleft else currbuff.size - ind
val until = ind + chunksize
copyChunk(currbuff.internalArray, ind, array, arrayIndex, until)
arrayIndex += chunksize
ind += chunksize
totalleft -= chunksize
buffind += 1
ind = 0
}
}
private def copyChunk(buffarr: Array[AnyRef], buffStart: Int, ra: Array[Any], arrayStart: Int, until: Int) {
Array.copy(buffarr, buffStart, ra, arrayStart, until - buffStart)
}
private def findStart(pos: Int) = {
var left = pos
var buffind = 0
while (left >= chain(buffind).size) {
left -= chain(buffind).size
buffind += 1
}
(buffind, left)
}
def split = {
val fp = howmany / 2
List(new CopyChainToArray(array, offset, fp), new CopyChainToArray(array, offset + fp, howmany - fp))
}
def shouldSplitFurther = howmany > collection.parallel.thresholdFromSize(size, parallelismLevel)
}
}
object ResizableParArrayCombiner {
def apply[T](c: ArrayBuffer[ExposedArrayBuffer[T]]): ResizableParArrayCombiner[T] = {
new { val chain = c } with ResizableParArrayCombiner[T] with EnvironmentPassingCombiner[T, ParArray[T]]
}
def apply[T](): ResizableParArrayCombiner[T] = apply(new ArrayBuffer[ExposedArrayBuffer[T]] += new ExposedArrayBuffer[T])
}
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