From 83c584026d593b6806e1107d645606b9498c05d6 Mon Sep 17 00:00:00 2001
From: Aleksandar Prokopec <axel22@gmail.com>
Date: Wed, 15 Feb 2012 10:42:29 +0100
Subject: Add `dup` method to ParCtrie iterators.

---
 src/library/scala/collection/mutable/Ctrie.scala   | 23 ++++++++++++++++++++--
 .../collection/parallel/mutable/ParCtrie.scala     |  7 ++++++-
 test/files/run/ctries/iterator.scala               | 10 ++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/library/scala/collection/mutable/Ctrie.scala b/src/library/scala/collection/mutable/Ctrie.scala
index 6ed3a516c4..dbd2129f0c 100644
--- a/src/library/scala/collection/mutable/Ctrie.scala
+++ b/src/library/scala/collection/mutable/Ctrie.scala
@@ -852,7 +852,7 @@ object Ctrie extends MutableMapFactory[Ctrie] {
 }
 
 
-private[collection] class CtrieIterator[K, V](var level: Int, ct: Ctrie[K, V], mustInit: Boolean = true) extends Iterator[(K, V)] {
+private[collection] class CtrieIterator[K, V](var level: Int, private var ct: Ctrie[K, V], mustInit: Boolean = true) extends Iterator[(K, V)] {
   var stack = new Array[Array[BasicNode]](7)
   var stackpos = new Array[Int](7)
   var depth = -1
@@ -920,6 +920,25 @@ private[collection] class CtrieIterator[K, V](var level: Int, ct: Ctrie[K, V], m
   
   protected def newIterator(_lev: Int, _ct: Ctrie[K, V], _mustInit: Boolean) = new CtrieIterator[K, V](_lev, _ct, _mustInit)
   
+  protected def dupTo(it: CtrieIterator[K, V]) = {
+    it.level = this.level
+    it.ct = this.ct
+    it.depth = this.depth
+    it.current = this.current
+    
+    // these need a deep copy
+    Array.copy(this.stack, 0, it.stack, 0, 7)
+    Array.copy(this.stackpos, 0, it.stackpos, 0, 7)
+    
+    // this one needs to be evaluated
+    if (this.subiter == null) it.subiter = null
+    else {
+      val lst = this.subiter.toList
+      this.subiter = lst.iterator
+      it.subiter = lst.iterator
+    }
+  }
+  
   /** Returns a sequence of iterators over subsets of this iterator.
    *  It's used to ease the implementation of splitters for a parallel version of the Ctrie.
    */
@@ -955,7 +974,7 @@ private[collection] class CtrieIterator[K, V](var level: Int, ct: Ctrie[K, V], m
     Seq(this)
   }
   
-  private def print {
+  def printDebug {
     println("ctrie iterator")
     println(stackpos.mkString(","))
     println("depth: " + depth)
diff --git a/src/library/scala/collection/parallel/mutable/ParCtrie.scala b/src/library/scala/collection/parallel/mutable/ParCtrie.scala
index 86624500fd..37add60df9 100644
--- a/src/library/scala/collection/parallel/mutable/ParCtrie.scala
+++ b/src/library/scala/collection/parallel/mutable/ParCtrie.scala
@@ -92,7 +92,12 @@ extends CtrieIterator[K, V](lev, ct, mustInit)
     level < maxsplits
   }
   
-  def dup = null // TODO necessary for views
+  def dup = {
+    val it = newIterator(0, ct, false)
+    dupTo(it)
+    it.iterated = this.iterated
+    it
+  }
   
   override def next() = {
     iterated += 1
diff --git a/test/files/run/ctries/iterator.scala b/test/files/run/ctries/iterator.scala
index 4bbf9009f0..85a6ab7623 100644
--- a/test/files/run/ctries/iterator.scala
+++ b/test/files/run/ctries/iterator.scala
@@ -274,6 +274,16 @@ object IteratorSpec extends Spec {
       while (it.hasNext) it.next()
     }
     
+    "be duplicated" in {
+      val sz = 50
+      val ct = collection.parallel.mutable.ParCtrie((0 until sz) zip (0 until sz): _*)
+      val it = ct.splitter
+      for (_ <- 0 until (sz / 2)) it.next()
+      val dupit = it.dup
+      
+      it.toList shouldEqual dupit.toList
+    }
+    
   }
   
 }
-- 
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