Skip to content
This repository
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 263 lines (185 sloc) 6.649 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2011, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */

package scala.collection.parallel.immutable

import scala.collection.parallel.ParSetLike
import scala.collection.parallel.Combiner
import scala.collection.parallel.IterableSplitter
import scala.collection.mutable.UnrolledBuffer.Unrolled
import scala.collection.mutable.UnrolledBuffer
import scala.collection.generic.ParSetFactory
import scala.collection.generic.CanCombineFrom
import scala.collection.generic.GenericParTemplate
import scala.collection.generic.GenericParCompanion
import scala.collection.generic.GenericCompanion
import scala.collection.immutable.{ HashSet, TrieIterator }

/** Immutable parallel hash set, based on hash tries.
*
* $paralleliterableinfo
*
* $sideeffects
*
* @tparam T the element type of the set
*
* @author Aleksandar Prokopec
* @since 2.9
*
* @define Coll immutable.ParHashSet
* @define coll immutable parallel hash set
*/
@SerialVersionUID(1L)
class ParHashSet[T] private[immutable] (private[this] val trie: HashSet[T])
extends ParSet[T]
   with GenericParTemplate[T, ParHashSet]
   with ParSetLike[T, ParHashSet[T], HashSet[T]]
   with Serializable
{
self =>

  def this() = this(HashSet.empty[T])

  override def companion: GenericCompanion[ParHashSet] with GenericParCompanion[ParHashSet] = ParHashSet

  override def empty: ParHashSet[T] = new ParHashSet[T]

  def splitter: IterableSplitter[T] = new ParHashSetIterator(trie.iterator, trie.size) with SCPI

  override def seq = trie

  def -(e: T) = new ParHashSet(trie - e)

  def +(e: T) = new ParHashSet(trie + e)

  def contains(e: T): Boolean = trie.contains(e)

  override def size = trie.size

  protected override def reuse[S, That](oldc: Option[Combiner[S, That]], newc: Combiner[S, That]) = oldc match {
    case Some(old) => old
    case None => newc
  }

  type SCPI = SignalContextPassingIterator[ParHashSetIterator]

  class ParHashSetIterator(var triter: Iterator[T], val sz: Int)
  extends super.ParIterator {
  self: SignalContextPassingIterator[ParHashSetIterator] =>
    var i = 0
    def dup = triter match {
      case t: TrieIterator[_] =>
        dupFromIterator(t.dupIterator)
      case _ =>
        val buff = triter.toBuffer
        triter = buff.iterator
        dupFromIterator(buff.iterator)
    }
    private def dupFromIterator(it: Iterator[T]) = {
      val phit = new ParHashSetIterator(it, sz) with SCPI
      phit.i = i
      phit
    }
    def split: Seq[ParIterator] = if (remaining < 2) Seq(this) else triter match {
      case t: TrieIterator[_] =>
        val previousRemaining = remaining
        val ((fst, fstlength), snd) = t.split
        val sndlength = previousRemaining - fstlength
        Seq(
          new ParHashSetIterator(fst, fstlength) with SCPI,
          new ParHashSetIterator(snd, sndlength) with SCPI
        )
      case _ =>
        // iterator of the collision map case
        val buff = triter.toBuffer
        val (fp, sp) = buff.splitAt(buff.length / 2)
        Seq(fp, sp) map { b => new ParHashSetIterator(b.iterator, b.length) with SCPI }
    }
    def next: T = {
      i += 1
      triter.next
    }
    def hasNext: Boolean = {
      i < sz
    }
    def remaining = sz - i
  }

}


/** $factoryInfo
* @define Coll immutable.ParHashSet
* @define coll immutable parallel hash set
*/
object ParHashSet extends ParSetFactory[ParHashSet] {
  def newCombiner[T]: Combiner[T, ParHashSet[T]] = HashSetCombiner[T]

  implicit def canBuildFrom[T]: CanCombineFrom[Coll, T, ParHashSet[T]] =
    new GenericCanCombineFrom[T]

  def fromTrie[T](t: HashSet[T]) = new ParHashSet(t)
}


private[immutable] abstract class HashSetCombiner[T]
extends collection.parallel.BucketCombiner[T, ParHashSet[T], Any, HashSetCombiner[T]](HashSetCombiner.rootsize) {
//self: EnvironmentPassingCombiner[T, ParHashSet[T]] =>
  import HashSetCombiner._
  import collection.parallel.tasksupport._
  val emptyTrie = HashSet.empty[T]

  def +=(elem: T) = {
    sz += 1
    val hc = emptyTrie.computeHash(elem)
    val pos = hc & 0x1f
    if (buckets(pos) eq null) {
      // initialize bucket
      buckets(pos) = new UnrolledBuffer[Any]
    }
    // add to bucket
    buckets(pos) += elem
    this
  }

  def result = {
    val bucks = buckets.filter(_ != null).map(_.headPtr)
    val root = new Array[HashSet[T]](bucks.length)

    executeAndWaitResult(new CreateTrie(bucks, root, 0, bucks.length))

    var bitmap = 0
    var i = 0
    while (i < rootsize) {
      if (buckets(i) ne null) bitmap |= 1 << i
      i += 1
    }
    val sz = root.foldLeft(0)(_ + _.size)

    if (sz == 0) new ParHashSet[T]
    else if (sz == 1) new ParHashSet[T](root(0))
    else {
      val trie = new HashSet.HashTrieSet(bitmap, root, sz)
      new ParHashSet[T](trie)
    }
  }

  /* tasks */

  class CreateTrie(bucks: Array[Unrolled[Any]], root: Array[HashSet[T]], offset: Int, howmany: Int)
  extends Task[Unit, CreateTrie] {
    var result = ()
    def leaf(prev: Option[Unit]) = {
      var i = offset
      val until = offset + howmany
      while (i < until) {
        root(i) = createTrie(bucks(i))
        i += 1
      }
    }
    private def createTrie(elems: Unrolled[Any]): HashSet[T] = {
      var trie = new HashSet[T]

      var unrolled = elems
      var i = 0
      while (unrolled ne null) {
        val chunkarr = unrolled.array
        val chunksz = unrolled.size
        while (i < chunksz) {
          val v = chunkarr(i).asInstanceOf[T]
          val hc = trie.computeHash(v)
          trie = trie.updated0(v, hc, rootbits)
          i += 1
        }
        i = 0
        unrolled = unrolled.next
      }

      trie
    }
    def split = {
      val fp = howmany / 2
      List(new CreateTrie(bucks, root, offset, fp), new CreateTrie(bucks, root, offset + fp, howmany - fp))
    }
    def shouldSplitFurther = howmany > collection.parallel.thresholdFromSize(root.length, parallelismLevel)
  }

}


object HashSetCombiner {
  def apply[T] = new HashSetCombiner[T] {} // was: with EnvironmentPassingCombiner[T, ParHashSet[T]] {}

  private[immutable] val rootbits = 5
  private[immutable] val rootsize = 1 << 5
}










































Something went wrong with that request. Please try again.