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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2011, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.collection.parallel
import scala.collection.Parallel
import scala.collection.{ IterableView, IterableViewLike }
import scala.collection.{ GenIterableView, GenIterableViewLike }
import scala.collection.GenTraversableOnce
import scala.collection.GenTraversable
import scala.collection.GenIterable
import scala.collection.GenSeq
import scala.collection.generic.{ CanBuildFrom, SliceInterval }
import scala.collection.generic.CanCombineFrom
import scala.collection.parallel.immutable.ParRange
import scala.language.implicitConversions
/** A template view of a non-strict view of parallel iterable collection.
*
* '''Note:''' Regular view traits have type parameters used to carry information
* about the type of the elements, type of the collection they are derived from and
* their own actual representation type. Parallel views have an additional parameter
* which carries information about the type of the sequential version of the view.
*
* @tparam T the type of the elements this view can traverse
* @tparam Coll the type of the parallel collection this view is derived from
* @tparam CollSeq the type of the sequential collection corresponding to the underlying parallel collection
* @tparam This the actual representation type of this view
* @tparam ThisSeq the type of the sequential representation of this view
*
* @since 2.9
*/
trait ParIterableViewLike[+T,
+Coll <: Parallel,
+CollSeq,
+This <: ParIterableView[T, Coll, CollSeq] with ParIterableViewLike[T, Coll, CollSeq, This, ThisSeq],
+ThisSeq <: IterableView[T, CollSeq] with IterableViewLike[T, CollSeq, ThisSeq]]
extends GenIterableView[T, Coll]
with GenIterableViewLike[T, Coll, This]
with ParIterable[T]
with ParIterableLike[T, This, ThisSeq]
{
self =>
override def foreach[U](f: T => U): Unit = super[ParIterableLike].foreach(f)
override protected[this] def newCombiner: Combiner[T, This] = throw new UnsupportedOperationException(this + ".newCombiner");
protected[this] def viewIdentifier: String
protected[this] def viewIdString: String
protected def underlying: Coll
/* wrappers */
trait Transformed[+S] extends ParIterableView[S, Coll, CollSeq] with super.Transformed[S] {
override def splitter: IterableSplitter[S]
override def iterator = splitter
def size = splitter.remaining
}
trait Sliced extends super.Sliced with Transformed[T] {
// override def slice(from1: Int, until1: Int): This = newSliced(from1 max 0, until1 max 0).asInstanceOf[This]
def splitter: IterableSplitter[T] = self.splitter.slice(from, until)
override def seq = self.seq.slice(from, until)
}
trait Mapped[S] extends super.Mapped[S] with Transformed[S]{
def splitter: IterableSplitter[S] = self.splitter.map(mapping)
override def seq = self.seq.map(mapping).asInstanceOf[IterableView[S, CollSeq]]
}
// only use if other is a ParIterable, otherwise force
trait Appended[U >: T] extends super.Appended[U] with Transformed[U] {
def restPar: ParIterable[U] = rest.asParIterable
def splitter: IterableSplitter[U] = self.splitter.appendParIterable[U, IterableSplitter[U]](restPar.splitter)
override def seq = self.seq.++(rest).asInstanceOf[IterableView[U, CollSeq]]
}
trait Forced[S] extends super.Forced[S] with Transformed[S] {
def forcedPar: ParIterable[S] = forced.asParIterable
def splitter: IterableSplitter[S] = forcedPar.splitter
override def seq = forcedPar.seq.view.asInstanceOf[IterableView[S, CollSeq]]
}
// only use if other is a ParSeq, otherwise force
trait Zipped[S] extends super.Zipped[S] with Transformed[(T, S)] {
def otherPar: ParSeq[S] = other.asParSeq
def splitter: IterableSplitter[(T, S)] = self.splitter zipParSeq otherPar.splitter
override def seq = (self.seq zip other).asInstanceOf[IterableView[(T, S), CollSeq]]
}
// only use if other is a ParSeq, otherwise force
trait ZippedAll[U >: T, S] extends super.ZippedAll[U, S] with Transformed[(U, S)] {
def otherPar: ParSeq[S] = other.asParSeq
def splitter: IterableSplitter[(U, S)] = self.splitter.zipAllParSeq(otherPar.splitter, thisElem, thatElem)
override def seq = (self.seq.zipAll(other, thisElem, thatElem)).asInstanceOf[IterableView[(U, S), CollSeq]]
}
protected[this] def thisParSeq: ParSeq[T] = mutable.ParArray.fromTraversables(this.iterator)
private[this] implicit def asThis(xs: Transformed[T]): This = xs.asInstanceOf[This]
/* operation overrides */
override def take(n: Int): This = newSliced(SliceInterval(0, n))
override def drop(n: Int): This = newSliced(SliceInterval(n, splitter.remaining))
override def splitAt(n: Int): (This, This) = (take(n), drop(n))
override def slice(from: Int, until: Int): This = newSliced(SliceInterval(from, until))
override def map[S, That](f: T => S)(implicit bf: CanBuildFrom[This, S, That]): That = newMapped(f).asInstanceOf[That]
override def ++[U >: T, That](xs: GenTraversableOnce[U])(implicit bf: CanBuildFrom[This, U, That]): That = newAppendedTryParIterable(xs.toTraversable).asInstanceOf[That]
override def filter(p: T => Boolean): This = newForced(thisParSeq.filter(p)).asInstanceOf[This]
override def filterNot(p: T => Boolean): This = newForced(thisParSeq.filterNot(p)).asInstanceOf[This]
override def partition(p: T => Boolean): (This, This) = {
val (t, f) = thisParSeq.partition(p)
(newForced(t).asInstanceOf[This], newForced(f).asInstanceOf[This])
}
override def takeWhile(p: T => Boolean): This = newForced(thisParSeq.takeWhile(p)).asInstanceOf[This]
override def dropWhile(p: T => Boolean): This = newForced(thisParSeq.dropWhile(p)).asInstanceOf[This]
override def span(p: T => Boolean): (This, This) = {
val (pref, suff) = thisParSeq.span(p)
(newForced(pref).asInstanceOf[This], newForced(suff).asInstanceOf[This])
}
override def flatMap[S, That](f: T => GenTraversableOnce[S])(implicit bf: CanBuildFrom[This, S, That]): That = newForced(thisParSeq.flatMap(f)).asInstanceOf[That]
override def zip[U >: T, S, That](that: GenIterable[S])(implicit bf: CanBuildFrom[This, (U, S), That]): That = newZippedTryParSeq(that).asInstanceOf[That]
override def zipWithIndex[U >: T, That](implicit bf: CanBuildFrom[This, (U, Int), That]): That =
newZipped(ParRange(0, splitter.remaining, 1, false)).asInstanceOf[That]
override def zipAll[S, U >: T, That](that: GenIterable[S], thisElem: U, thatElem: S)(implicit bf: CanBuildFrom[This, (U, S), That]): That =
newZippedAllTryParSeq(that, thisElem, thatElem).asInstanceOf[That]
override def force[U >: T, That](implicit bf: CanBuildFrom[Coll, U, That]) = bf ifParallel { pbf =>
tasksupport.executeAndWaitResult(new Force(pbf, splitter).mapResult(_.result).asInstanceOf[Task[That, ResultMapping[_, Force[U, That], That]]])
} otherwise {
val b = bf(underlying)
b ++= this.iterator
b.result
}
/* wrapper virtual ctors */
protected def newSliced(_endpoints: SliceInterval): Transformed[T] = new { val endpoints = _endpoints } with Sliced
protected def newMapped[S](f: T => S): Transformed[S] = new Mapped[S] { val mapping = f }
protected def newForced[S](xs: => GenSeq[S]): Transformed[S] = new Forced[S] { val forced = xs }
protected def newAppended[U >: T](that: GenTraversable[U]): Transformed[U] = new Appended[U] { val rest = that }
protected def newDroppedWhile(p: T => Boolean) = unsupported
protected def newTakenWhile(p: T => Boolean) = unsupported
protected def newFlatMapped[S](f: T => GenTraversableOnce[S]) = unsupported
protected def newFiltered(p: T => Boolean) = unsupported
protected def newZipped[S](that: GenIterable[S]): Transformed[(T, S)] = new Zipped[S] { val other = that }
protected def newZippedAll[U >: T, S](that: GenIterable[S], _thisElem: U, _thatElem: S): Transformed[(U, S)] = new ZippedAll[U, S] {
val other = that
val thisElem = _thisElem
val thatElem = _thatElem
}
/* argument sequence dependent ctors */
protected def newForcedTryParIterable[S](xs: => GenSeq[S]): Transformed[S] = {
if (xs.isParIterable) newForced[S](xs)
else newForced(mutable.ParArray.fromTraversables(xs))
}
protected def newAppendedTryParIterable[U >: T](that: GenTraversable[U]): Transformed[U] = {
// we only append if `that` is a parallel iterable, i.e. it has a splitter
if (that.isParIterable) newAppended(that)
else newAppended(mutable.ParArray.fromTraversables(that))
}
protected def newZippedTryParSeq[S](that: GenIterable[S]): Transformed[(T, S)] = {
if (that.isParSeq) newZipped[S](that)
else newZipped[S](mutable.ParArray.fromTraversables(that))
}
protected def newZippedAllTryParSeq[S, U >: T](that: GenIterable[S], thisElem: U, thatElem: S): Transformed[(U, S)] = {
if (that.isParSeq) newZippedAll(that, thisElem, thatElem)
else newZippedAll(mutable.ParArray.fromTraversables(that), thisElem, thatElem)
}
/* tasks */
protected[this] class Force[U >: T, That](cbf: CanCombineFrom[Coll, U, That], protected[this] val pit: IterableSplitter[T])
extends Transformer[Combiner[U, That], Force[U, That]] {
var result: Combiner[U, That] = null
def leaf(prev: Option[Combiner[U, That]]) = result = pit.copy2builder[U, That, Combiner[U, That]](reuse(prev, cbf(self.underlying)))
protected[this] def newSubtask(p: IterableSplitter[T]) = new Force(cbf, p)
override def merge(that: Force[U, That]) = result = result combine that.result
}
}
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