initial checkin of new immutable vectors

1 files changed, 1024 insertions, 19 deletions

diff --git a/src/library/scala/collection/immutable/Vector.scala b/src/library/scala/collection/immutable/Vector.scala
index 7e76549f7e..289fbd61d9 100644
--- a/src/library/scala/collection/immutable/Vector.scala
+++ b/src/library/scala/collection/immutable/Vector.scala
@@ -12,33 +12,1038 @@
 package scala.collection
 package immutable
 
-import generic._
-import mutable.{Builder, ArrayBuffer}
+import scala.annotation.unchecked.uncheckedVariance
+
+import scala.collection.generic._
+import scala.collection.mutable.Builder
+
+
+/**
+ * @since 2.8
+ */
+object Vector extends SeqFactory[Vector] {
+  implicit def builderFactory[A]: BuilderFactory[A, Vector[A], Coll] =
+    new VirtualBuilderFactory[A]
+  def newBuilder[A]: Builder[A, Vector[A]] =
+    new VectorBuilder[A]
+
+  // TODO: override val empty = new Vector(0, 0, 0)
+}
+
+
+trait VectorPointer[T] {
+    var depth: Int = _
+    var display0: Array[AnyRef] = _
+    var display1: Array[AnyRef] = _
+    var display2: Array[AnyRef] = _
+    var display3: Array[AnyRef] = _
+    var display4: Array[AnyRef] = _
+    var display5: Array[AnyRef] = _
+
+    // used
+    final def initFrom[U](that: VectorPointer[U]) = {
+      depth = that.depth
+      (depth - 1) match {
+        case 0 =>
+          display0 = that.display0
+        case 1 =>
+          display1 = that.display1
+          display0 = that.display0
+        case 2 =>
+          display2 = that.display2
+          display1 = that.display1
+          display0 = that.display0
+        case 3 =>
+          display3 = that.display3
+          display2 = that.display2
+          display1 = that.display1
+          display0 = that.display0
+        case 4 =>
+          display4 = that.display4
+          display3 = that.display3
+          display2 = that.display2
+          display1 = that.display1
+          display0 = that.display0
+        case 5 =>
+          display5 = that.display5
+          display4 = that.display4
+          display3 = that.display3
+          display2 = that.display2
+          display1 = that.display1
+          display0 = that.display0
+      }
+    }
+
+    // used
+    final def getElem(index: Int, xor: Int): T = {
+      if (xor < (1 << 5)) { // level = 0
+        display0(index & 31).asInstanceOf[T]
+      } else
+      if (xor < (1 << 10)) { // level = 1
+        display1((index >> 5) & 31).asInstanceOf[Array[AnyRef]](index & 31).asInstanceOf[T]
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]((index >> 5) & 31).asInstanceOf[Array[AnyRef]](index & 31).asInstanceOf[T]
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        display3((index >> 15) & 31).asInstanceOf[Array[AnyRef]]((index >> 10) & 31).asInstanceOf[Array[AnyRef]]((index >> 5) & 31).asInstanceOf[Array[AnyRef]](index & 31).asInstanceOf[T]
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        display4((index >> 20) & 31).asInstanceOf[Array[AnyRef]]((index >> 15) & 31).asInstanceOf[Array[AnyRef]]((index >> 10) & 31).asInstanceOf[Array[AnyRef]]((index >> 5) & 31).asInstanceOf[Array[AnyRef]](index & 31).asInstanceOf[T]
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        display5((index >> 25) & 31).asInstanceOf[Array[AnyRef]]((index >> 20) & 31).asInstanceOf[Array[AnyRef]]((index >> 15) & 31).asInstanceOf[Array[AnyRef]]((index >> 10) & 31).asInstanceOf[Array[AnyRef]]((index >> 5) & 31).asInstanceOf[Array[AnyRef]](index & 31).asInstanceOf[T]
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+    final def gotoZeroInit(elems: Array[AnyRef]) = (depth - 1) match { // goto pos zero
+      case 5 =>
+        display5 = elems.asInstanceOf[Array[AnyRef]]
+        display4 = display5(0).asInstanceOf[Array[AnyRef]]
+        display3 = display4(0).asInstanceOf[Array[AnyRef]]
+        display2 = display3(0).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      case 4 =>
+        display4 = elems.asInstanceOf[Array[AnyRef]]
+        display3 = display4(0).asInstanceOf[Array[AnyRef]]
+        display2 = display3(0).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      case 3 =>
+        display3 = elems.asInstanceOf[Array[AnyRef]]
+        display2 = display3(0).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      case 2 =>
+        display2 = elems.asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      case 1 =>
+        display1 = elems.asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      case 0 =>
+        display0 = elems.asInstanceOf[Array[AnyRef]]
+    }
+
+    // USED BY ITERATOR
+
+    // xor: oldIndex ^ index
+    final def gotoNextBlockStart(index: Int, xor: Int): Unit = { // goto block start pos
+      if (xor < (1 << 10)) { // level = 1
+        display0 = display1((index >> 5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        display1 = display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        display2 = display3((index >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        display3 = display4((index >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        display2 = display3(0).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        display4 = display5((index >> 25) & 31).asInstanceOf[Array[AnyRef]]
+        display3 = display4(0).asInstanceOf[Array[AnyRef]]
+        display2 = display3(0).asInstanceOf[Array[AnyRef]]
+        display1 = display2(0).asInstanceOf[Array[AnyRef]]
+        display0 = display1(0).asInstanceOf[Array[AnyRef]]
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+    // USED BY BUILDER
+
+    // xor: oldIndex ^ index
+    final def gotoNextBlockStartClean(index: Int, xor: Int): Unit = { // goto block start pos
+      if (xor < (1 << 10)) { // level = 1
+        if (depth == 1) { display1 = new Array(32); display1(0) = display0; depth+=1}
+        display0 = new Array(32)
+        display1((index >>  5) & 31) = display0
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        if (depth == 2) { display2 = new Array(32); display2(0) = display1; depth+=1}
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display1((index >>  5) & 31) = display0
+        display2((index >> 10) & 31) = display1
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        if (depth == 3) { display3 = new Array(32); display3(0) = display2; depth+=1}
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+        display1((index >>  5) & 31) = display0
+        display2((index >> 10) & 31) = display1
+        display3((index >> 15) & 31) = display2
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        if (depth == 4) { display4 = new Array(32); display4(0) = display3; depth+=1}
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+        display3 = new Array(32)
+        display1((index >>  5) & 31) = display0
+        display2((index >> 10) & 31) = display1
+        display3((index >> 15) & 31) = display2
+        display4((index >> 20) & 31) = display3
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        if (depth == 5) { display5 = new Array(32); display5(0) = display4; depth+=1}
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+        display3 = new Array(32)
+        display4 = new Array(32)
+        display1((index >>  5) & 31) = display0
+        display2((index >> 10) & 31) = display1
+        display3((index >> 15) & 31) = display2
+        display4((index >> 20) & 31) = display3
+        display5((index >> 25) & 31) = display4
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+
+
+    // STUFF BELOW USED BY APPEND
+
+    final def copyOf(a: Array[AnyRef]) = {
+//      //println("copy")
+      val b = new Array[AnyRef](a.length)
+      System.arraycopy(a, 0, b, 0, a.length)
+      b
+    }
+
+    final def nullSlotAndCopy(array: Array[AnyRef], index: Int) = {
+//      //println("copy and null")
+      val x = array(index)
+//TODO
+//      array(index) = null
+      copyOf(x.asInstanceOf[Array[AnyRef]])
+    }
+
+
+    // USED IN APPEND
+    // create a new block at the bottom level, and possible ex
+
+    final def gotoFreshPosClean(oldIndex: Int, newIndex: Int, xor: Int): Unit = { // goto block start pos
+      if (xor < (1 << 5)) { // level = 0
+        //println("XXX clean with low xor")
+      } else
+      if (xor < (1 << 10)) { // level = 1
+        if (depth == 1) {
+          display1 = new Array(32)
+          display1((oldIndex >>  5) & 31) = display0
+          depth +=1
+        }
+        display0 = new Array(32)
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        if (depth == 2) {
+          display2 = new Array(32)
+          display2((oldIndex >> 10) & 31) = display1
+          depth +=1
+        }
+        display1 = display2((newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        if (display1 == null) display1 = new Array(32)
+        display0 = new Array(32)
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        if (depth == 3) {
+          display3 = new Array(32)
+          display3((oldIndex >> 15) & 31) = display2
+          display2 = new Array(32)
+          display1 = new Array(32)
+          depth +=1
+        }
+        display2 = display3((newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        if (display2 == null) display2 = new Array(32)
+        display1 = display2((newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        if (display1 == null) display1 = new Array(32)
+        display0 = new Array(32)
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        if (depth == 4) {
+          display4 = new Array(32)
+          display4((oldIndex >> 20) & 31) = display3
+          display3 = new Array(32)
+          display2 = new Array(32)
+          display1 = new Array(32)
+          depth +=1
+        }
+        display3 = display4((newIndex >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        if (display3 == null) display3 = new Array(32)
+        display2 = display3((newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        if (display2 == null) display2 = new Array(32)
+        display1 = display2((newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        if (display1 == null) display1 = new Array(32)
+        display0 = new Array(32)
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        if (depth == 5) {
+          display5 = new Array(32)
+          display5((oldIndex >>  25) & 31) = display4
+          display4 = new Array(32)
+          display3 = new Array(32)
+          display2 = new Array(32)
+          display1 = new Array(32)
+          depth +=1
+        }
+        display4 = display5((newIndex >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        if (display4 == null) display4 = new Array(32)
+        display3 = display4((newIndex >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        if (display3 == null) display3 = new Array(32)
+        display2 = display3((newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        if (display2 == null) display2 = new Array(32)
+        display1 = display2((newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        if (display1 == null) display1 = new Array(32)
+        display0 = new Array(32)
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+      stabilize(newIndex)
+    }
+
+
+    // xor: oldIndex ^ index
+    final def XgotoFreshPosClean(oldIndex: Int, newIndex: Int, xor: Int): Unit = { // goto block start pos
+      if (xor < (1 << 10)) { // level = 1
+        if (depth == 1) { display1 = new Array(32); depth +=1 }
+        else { display1 = copyOf(display1) }
+        display1((oldIndex >>  5) & 31) = display0
+        display0 = new Array(32)
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        if (depth == 2) { display2 = new Array(32); depth+=1}
+        else { display2 = copyOf(display2) }
+        display1 = copyOf(display1)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display0 = new Array(32)
+        display1 = new Array(32)
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        if (depth == 3) { display3 = new Array(32); depth+=1}
+        else { display3 = copyOf(display3) }
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        if (depth == 4) { display4 = new Array(32); depth+=1}
+        else { display4 = copyOf(display4) }
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display3 = copyOf(display3)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display4((oldIndex >> 20) & 31) = display3
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+        display3 = new Array(32)
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        if (depth == 5) { display5 = new Array(32); depth+=1 }
+        else { display5 = copyOf(display5) }
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display3 = copyOf(display3)
+        display4 = copyOf(display4)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display4((oldIndex >> 20) & 31) = display3
+        display5((oldIndex >> 25) & 31) = display4
+        display0 = new Array(32)
+        display1 = new Array(32)
+        display2 = new Array(32)
+        display3 = new Array(32)
+        display4 = new Array(32)
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+    /// USED IN UPDATE AND APPEND BACK
+
+    // prepare for writing at an existing position
+
+    // xor: oldIndex ^ index
+    // precondition: the pointers (and only those) on path oldIndex to display0 are null
+    // postconditions:
+    // the pointers (and only those) on path newIndex to display0 are null
+    // path oldIndex will be updated with previous displayX
+    // displayX will be fresh, writable copies of path newIndex
+
+
+    final def gotoPosClean(oldIndex: Int, newIndex: Int, xor: Int): Unit = {
+      if (depth > 1) {
+        gotoPos(newIndex, xor)
+        stabilize(newIndex)
+      }
+    }
+
+    final def XgotoPosClean(oldIndex: Int, newIndex: Int, xor: Int): Unit = { // goto pos index
+      if (xor < (1 <<  5)) { // level = 0
+//        //println("inside same chunk")
+        display0 = copyOf(display0)
+      } else
+      if (xor < (1 << 10)) { // level = 1
+//        //println("transfer to chunk at level 1 ("+oldIndex+"->"+newIndex+")")
+        display1 = copyOf(display1)
+        display1((oldIndex >> 5) & 31) = display0
+        display0 = nullSlotAndCopy(display1, (newIndex >>  5) & 31)
+      } else
+      if (xor < (1 << 15)) { // level = 2
+//        //println("transfer to chunk at level 1")
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display1 = nullSlotAndCopy(display2, (newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = nullSlotAndCopy(display1, (newIndex >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display3 = copyOf(display3)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display2 = nullSlotAndCopy(display3, (newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = nullSlotAndCopy(display2, (newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = nullSlotAndCopy(display1, (newIndex >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display3 = copyOf(display3)
+        display4 = copyOf(display4)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display4((oldIndex >> 20) & 31) = display3
+        display3 = nullSlotAndCopy(display4, (newIndex >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        display2 = nullSlotAndCopy(display3, (newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = nullSlotAndCopy(display2, (newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = nullSlotAndCopy(display1, (newIndex >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        display1 = copyOf(display1)
+        display2 = copyOf(display2)
+        display3 = copyOf(display3)
+        display4 = copyOf(display4)
+        display5 = copyOf(display5)
+        display1((oldIndex >>  5) & 31) = display0
+        display2((oldIndex >> 10) & 31) = display1
+        display3((oldIndex >> 15) & 31) = display2
+        display4((oldIndex >> 20) & 31) = display3
+        display5((oldIndex >> 25) & 31) = display4
+        display4 = nullSlotAndCopy(display5, (newIndex >> 25) & 31).asInstanceOf[Array[AnyRef]]
+        display3 = nullSlotAndCopy(display4, (newIndex >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        display2 = nullSlotAndCopy(display3, (newIndex >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = nullSlotAndCopy(display2, (newIndex >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = nullSlotAndCopy(display1, (newIndex >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+
+    def debug(): Unit = {
+      return
+/*
+      //println("DISPLAY 5: " + display5 + " ---> " + (if (display5 ne null) display5.map(x=> if (x eq null) "." else x + "->" +x.asInstanceOf[Array[AnyRef]].mkString("")).mkString(" ") else "null"))
+      //println("DISPLAY 4: " + display4 + " ---> " + (if (display4 ne null) display4.map(x=> if (x eq null) "." else x + "->" +x.asInstanceOf[Array[AnyRef]].mkString("")).mkString(" ") else "null"))
+      //println("DISPLAY 3: " + display3 + " ---> " + (if (display3 ne null) display3.map(x=> if (x eq null) "." else x + "->" +x.asInstanceOf[Array[AnyRef]].mkString("")).mkString(" ") else "null"))
+      //println("DISPLAY 2: " + display2 + " ---> " + (if (display2 ne null) display2.map(x=> if (x eq null) "." else x + "->" +x.asInstanceOf[Array[AnyRef]].mkString("")).mkString(" ") else "null"))
+      //println("DISPLAY 1: " + display1 + " ---> " + (if (display1 ne null) display1.map(x=> if (x eq null) "." else x + "->" +x.asInstanceOf[Array[AnyRef]].mkString("")).mkString(" ") else "null"))
+      //println("DISPLAY 0: " + display0 + " ---> " + (if (display0 ne null) display0.map(x=> if (x eq null) "." else x.toString).mkString(" ") else "null"))
+*/
+      //println("DISPLAY 5: " + (if (display5 ne null) display5.map(x=> if (x eq null) "." else x.asInstanceOf[Array[AnyRef]].deepMkString("[","","]")).mkString(" ") else "null"))
+      //println("DISPLAY 4: " + (if (display4 ne null) display4.map(x=> if (x eq null) "." else x.asInstanceOf[Array[AnyRef]].deepMkString("[","","]")).mkString(" ") else "null"))
+      //println("DISPLAY 3: " + (if (display3 ne null) display3.map(x=> if (x eq null) "." else x.asInstanceOf[Array[AnyRef]].deepMkString("[","","]")).mkString(" ") else "null"))
+      //println("DISPLAY 2: " + (if (display2 ne null) display2.map(x=> if (x eq null) "." else x.asInstanceOf[Array[AnyRef]].deepMkString("[","","]")).mkString(" ") else "null"))
+      //println("DISPLAY 1: " + (if (display1 ne null) display1.map(x=> if (x eq null) "." else x.asInstanceOf[Array[AnyRef]].deepMkString("[","","]")).mkString(" ") else "null"))
+      //println("DISPLAY 0: " + (if (display0 ne null) display0.map(x=> if (x eq null) "." else x.toString).mkString(" ") else "null"))
+    }
+
+
+    // make sure there is no aliasing
+
+    // TODO: optimize
+    final def stabilize(index: Int) = {
+//      debug()
+      display0 = copyOf(display0)
+      if (depth > 1) {
+        display1 = copyOf(display1)
+        display1((index >>  5) & 31) = display0
+      }
+      if (depth > 2) {
+        display2 = copyOf(display2)
+        display2((index >> 10) & 31) = display1
+      }
+      if (depth > 3) {
+        display3 = copyOf(display3)
+        display3((index >> 15) & 31) = display2
+      }
+      if (depth > 4) {
+        display4 = copyOf(display4)
+        display4((index >> 20) & 31) = display3
+      }
+      if (depth > 5) {
+        display5 = copyOf(display5)
+        display5((index >> 25) & 31) = display4
+      }
+    }
+
+
+
+
+    // go to specified position
+
+    // xor: oldIndex ^ index
+    final def gotoPos(index: Int, xor: Int): Unit = { // goto pos index
+      if (xor < (1 << 10)) { // level = 1
+        display0 = display1((index >> 5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 15)) { // level = 2
+        display1 = display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = display1((index >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 20)) { // level = 3
+        display2 = display3((index >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = display1((index >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 25)) { // level = 4
+        display3 = display4((index >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        display2 = display3((index >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = display1((index >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else
+      if (xor < (1 << 30)) { // level = 5
+        display4 = display5((index >> 25) & 31).asInstanceOf[Array[AnyRef]]
+        display3 = display4((index >> 20) & 31).asInstanceOf[Array[AnyRef]]
+        display2 = display3((index >> 15) & 31).asInstanceOf[Array[AnyRef]]
+        display1 = display2((index >> 10) & 31).asInstanceOf[Array[AnyRef]]
+        display0 = display1((index >>  5) & 31).asInstanceOf[Array[AnyRef]]
+      } else { // level = 6
+        throw new IllegalArgumentException()
+      }
+    }
+
+}
+
+
+
 
 /** A subtrait of <code>collection.Vector</code> which represents sequences
  *  that cannot be mutated.
  *
  *  @since 2.8
  */
-trait Vector[+A] extends Seq[A]
-                    with scala.collection.Vector[A]
-                    with GenericTraversableTemplate[A, Vector]
-                    with VectorLike[A, Vector[A]] {
+class Vector[+A](startIndex: Int, endIndex: Int, focus: Int) extends scala.collection.immutable.Seq[A]
+                  with scala.collection.Seq[A]
+                  with GenericTraversableTemplate[A, Vector]
+                  with SeqLike[A, Vector[A]]
+                  with VectorPointer[A @uncheckedVariance] {
+
+  //assert(startIndex >= 0, startIndex+"<0")
+  //assert(startIndex <= endIndex, startIndex+">"+endIndex)
+  //assert(focus >= 0, focus+"<0")
+  //assert(focus <= endIndex, focus+">"+endIndex)
+
   override def companion: GenericCompanion[Vector] = Vector
+
+  def length = endIndex - startIndex
+
+  override def iterator: VectorIterator[A] = {
+    val s = new VectorIterator[A](startIndex, endIndex)
+    s.initFrom(this)
+    s.stabilize(focus)
+    s.gotoPos(startIndex, startIndex ^ focus)
+    s
+  }
+
+  // TODO: reverse
+  // TODO: reverseIterator
+
+  private def checkRangeConvert(index: Int) = {
+    val idx = index + startIndex
+    if (0 <= index && idx < endIndex)
+      idx
+    else
+      throw new IndexOutOfBoundsException(index.toString)
+  }
+
+  def apply(index: Int): A = {
+    val idx = checkRangeConvert(index)
+//    //println("get elem: "+index + "/"+idx + "(focus:" +focus+" xor:"+(idx^focus)+" depth:"+depth+")")
+    getElem(idx, idx ^ focus)
+  }
+
+  def update[B>:A](index: Int, value: B): Vector[B] = {
+    val idx = checkRangeConvert(index)
+    val s = new Vector[B](startIndex, endIndex, idx)
+    s.initFrom(this)
+    s.gotoPosClean(focus, idx, focus ^ idx)
+    s.display0(idx & 0x1f) = value.asInstanceOf[AnyRef]
+    s
+  }
+
+  override def take(n: Int): Vector[A] = {
+    if (n < 0) throw new IllegalArgumentException(n.toString)
+    if (startIndex + n < endIndex) {
+      dropBack0(startIndex + n)
+    } else
+      this
+  }
+
+  override def drop(n: Int): Vector[A] = {
+    if (n < 0) throw new IllegalArgumentException(n.toString)
+    if (startIndex + n < endIndex) {
+      dropFront0(startIndex + n)
+    } else
+      Vector.empty
+  }
+
+  override def takeRight(n: Int): Vector[A] = {
+    if (n < 0) throw new IllegalArgumentException(n.toString)
+    if (endIndex - n > startIndex) {
+      dropFront0(endIndex + n)
+    } else
+      this
+  }
+
+  override def dropRight(n: Int): Vector[A] = {
+    if (n < 0) throw new IllegalArgumentException(n.toString)
+    if (endIndex - n > startIndex) {
+      dropBack0(endIndex - n)
+    } else
+      Vector.empty
+  }
+
+
+
+  private def copyRange(array: Array[AnyRef], oldLeft: Int, newLeft: Int) = {
+    val elems = new Array[AnyRef](32)
+    System.arraycopy(array, oldLeft, elems, newLeft, 32 - Math.max(newLeft,oldLeft))
+    elems
+  }
+
+  private def shiftTopLevel(oldLeft: Int, newLeft: Int) = (depth - 1) match {
+    case 0 =>
+      display0 = copyRange(display0, oldLeft, newLeft)
+    case 1 =>
+      display1 = copyRange(display1, oldLeft, newLeft)
+    case 2 =>
+      display2 = copyRange(display2, oldLeft, newLeft)
+    case 3 =>
+      display3 = copyRange(display3, oldLeft, newLeft)
+    case 4 =>
+      display4 = copyRange(display4, oldLeft, newLeft)
+    case 5 =>
+      display5 = copyRange(display5, oldLeft, newLeft)
+  }
+
+  private def cleanLeftEdge(cutIndex: Int) = (depth - 1) match {
+    case 5 =>
+      for (i <- 0 until ((cutIndex >>> 25) & 0x1f)) display5(i) = null
+      for (i <- 0 until ((cutIndex >>> 20) & 0x1f)) display4(i) = null
+      for (i <- 0 until ((cutIndex >>> 15) & 0x1f)) display3(i) = null
+      for (i <- 0 until ((cutIndex >>> 10) & 0x1f)) display2(i) = null
+      for (i <- 0 until ((cutIndex >>>  5) & 0x1f)) display1(i) = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+    case 4 =>
+      display5 = null
+      for (i <- 0 until ((cutIndex >>> 20) & 0x1f)) display4(i) = null
+      for (i <- 0 until ((cutIndex >>> 15) & 0x1f)) display3(i) = null
+      for (i <- 0 until ((cutIndex >>> 10) & 0x1f)) display2(i) = null
+      for (i <- 0 until ((cutIndex >>>  5) & 0x1f)) display1(i) = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+    case 3 =>
+      display5 = null
+      display4 = null
+      for (i <- 0 until ((cutIndex >>> 15) & 0x1f)) display3(i) = null
+      for (i <- 0 until ((cutIndex >>> 10) & 0x1f)) display2(i) = null
+      for (i <- 0 until ((cutIndex >>>  5) & 0x1f)) display1(i) = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+    case 2 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      for (i <- 0 until ((cutIndex >>> 10) & 0x1f)) display2(i) = null
+      for (i <- 0 until ((cutIndex >>>  5) & 0x1f)) display1(i) = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+    case 1 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      display2 = null
+      for (i <- 0 until ((cutIndex >>>  5) & 0x1f)) display1(i) = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+    case 0 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      display2 = null
+      display1 = null
+      for (i <- 0 until ((cutIndex >>>  0) & 0x1f)) display0(i) = null
+  }
+
+  private def cleanRightEdge(cutIndex: Int) = (depth - 1) match {
+    case 5 =>
+      for (i <- ((cutIndex >>> 25) & 0x1f) until 32) display5(i) = null
+      for (i <- ((cutIndex >>> 20) & 0x1f) until 32) display4(i) = null
+      for (i <- ((cutIndex >>> 15) & 0x1f) until 32) display3(i) = null
+      for (i <- ((cutIndex >>> 10) & 0x1f) until 32) display2(i) = null
+      for (i <- ((cutIndex >>>  5) & 0x1f) until 32) display1(i) = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+    case 4 =>
+      display5 = null
+      for (i <- ((cutIndex >>> 20) & 0x1f) until 32) display4(i) = null
+      for (i <- ((cutIndex >>> 15) & 0x1f) until 32) display3(i) = null
+      for (i <- ((cutIndex >>> 10) & 0x1f) until 32) display2(i) = null
+      for (i <- ((cutIndex >>>  5) & 0x1f) until 32) display1(i) = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+    case 3 =>
+      display5 = null
+      display4 = null
+      for (i <- ((cutIndex >>> 15) & 0x1f) until 32) display3(i) = null
+      for (i <- ((cutIndex >>> 10) & 0x1f) until 32) display2(i) = null
+      for (i <- ((cutIndex >>>  5) & 0x1f) until 32) display1(i) = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+    case 2 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      for (i <- ((cutIndex >>> 10) & 0x1f) until 32) display2(i) = null
+      for (i <- ((cutIndex >>>  5) & 0x1f) until 32) display1(i) = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+    case 1 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      display2 = null
+      for (i <- ((cutIndex >>>  5) & 0x1f) until 32) display1(i) = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+    case 0 =>
+      display5 = null
+      display4 = null
+      display3 = null
+      display2 = null
+      display1 = null
+      for (i <- ((cutIndex >>>  0) & 0x1f) until 32) display0(i) = null
+  }
+
+  private def requiredDepth(xor: Int) = {
+    if (xor < (1 <<  5)) 1
+    else if (xor < (1 << 10)) 2
+    else if (xor < (1 << 15)) 3
+    else if (xor < (1 << 20)) 4
+    else if (xor < (1 << 25)) 5
+    else if (xor < (1 << 30)) 6
+    else throw new IllegalArgumentException()
+  }
+
+  private def dropFront0(cutIndex: Int): Vector[A] = {
+    var blockIndex = cutIndex & ~31
+    var lo = cutIndex & 31
+
+    val xor = cutIndex ^ (endIndex - 1)
+    val d = requiredDepth(xor)
+    val shift = (cutIndex & ~((1 << (5*d))-1))
+
+    //println("cut front at " + cutIndex + ".." + endIndex + " (xor: "+xor+" shift: " + shift + " d: " + d +")")
+
+    val s = new Vector(cutIndex-shift, endIndex-shift, blockIndex-shift)
+    s.initFrom(this)
+    if (s.depth > 1)
+      s.gotoPos(blockIndex, focus ^ blockIndex)
+    s.depth = d
+    s.stabilize(blockIndex-shift)
+    s.cleanLeftEdge(cutIndex-shift)
+    s
+  }
+
+  private def dropBack0(cutIndex: Int): Vector[A] = {
+    var blockIndex = (cutIndex - 1) & ~31
+    var lo = ((cutIndex - 1) & 31) + 1
+
+    val xor = startIndex ^ (cutIndex - 1)
+    val d = requiredDepth(xor)
+
+    //println("cut back at " + startIndex + ".." + cutIndex + " (xor: "+xor+" d: " + d +")")
+
+    val s = new Vector(startIndex, cutIndex, blockIndex)
+    s.initFrom(this)
+    if (s.depth > 1)
+      s.gotoPos(blockIndex, focus ^ blockIndex)
+    s.depth = d
+    s.stabilize(blockIndex)
+    s.cleanRightEdge(cutIndex)
+    s
+  }
+
+
+  def appendFront[B>:A](value: B): Vector[B] = {
+    if (endIndex != startIndex) {
+      var blockIndex = (startIndex - 1) & ~31
+      var lo = (startIndex - 1) & 31
+
+      if (blockIndex + 32 == startIndex) {
+
+        val freeSpace = ((1<<5*(depth)) - endIndex)
+        val shift = freeSpace & ~((1<<5*(depth-1))-1)
+        val shiftBlocks = freeSpace >>> 5*(depth-1)
+
+        //println("----- appendFront " + value + " at " + (startIndex - 1) + " reached block start")
+        if (shift != 0) {
+          // case A: we can shift right on the top level
+          debug
+          //println("shifting right by " + shiftBlocks + " at level " + (depth-1) + " (had "+freeSpace+" free space)")
+
+          if (depth > 1) {
+            val newBlockIndex = blockIndex + shift
+            val newFocus = focus + shift
+            val s = new Vector(startIndex - 1 + shift, endIndex + shift, newBlockIndex)
+            s.initFrom(this)
+            s.shiftTopLevel(0, shiftBlocks) // shift right by n blocks
+            s.debug
+            s.gotoFreshPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+            s.display0(lo) = value.asInstanceOf[AnyRef]
+            //assert(depth == s.depth)
+            s
+          } else {
+            val newBlockIndex = blockIndex + 32
+            val newFocus = focus
+
+            //assert(newBlockIndex == 0)
+            //assert(newFocus == 0)
+
+            val s = new Vector(startIndex - 1 + shift, endIndex + shift, newBlockIndex)
+            s.initFrom(this)
+            s.shiftTopLevel(0, shiftBlocks) // shift right by n elements
+            s.gotoPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+            s.display0(shift-1) = value.asInstanceOf[AnyRef]
+            s.debug
+            s
+          }
+        } else if (blockIndex < 0) {
+          // case B: we need to move the whole structure
+          val move = (1 << 5*(depth+1)) - (1 << 5*(depth))
+          //println("moving right by " + move + " at level " + (depth-1) + " (had "+freeSpace+" free space)")
+
+          val newBlockIndex = blockIndex + move
+          val newFocus = focus + move
+
+          val s = new Vector(startIndex - 1 + move, endIndex + move, newBlockIndex)
+          s.initFrom(this)
+          s.debug
+          s.gotoFreshPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex) // could optimize: we know it will create a whole branch
+          s.display0(lo) = value.asInstanceOf[AnyRef]
+          s.debug
+          //assert(s.depth == depth+1)
+          s
+        } else {
+          val newBlockIndex = blockIndex
+          val newFocus = focus
+
+          val s = new Vector(startIndex - 1, endIndex, newBlockIndex)
+          s.initFrom(this)
+          s.gotoFreshPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+          s.display0(lo) = value.asInstanceOf[AnyRef]
+          //assert(s.depth == depth)
+          s
+        }
+
+      } else {
+//        //println("will make writable block (from "+focus+") at: " + blockIndex)
+        val s = new Vector(startIndex - 1, endIndex, blockIndex)
+        s.initFrom(this)
+        s.gotoPosClean(focus, blockIndex, focus ^ blockIndex)
+        s.display0(lo) = value.asInstanceOf[AnyRef]
+        s
+      }
+    } else {
+      // empty vector, just insert single element at the back
+      val elems = new Array[AnyRef](32)
+      elems(31) = value.asInstanceOf[AnyRef]
+      val s = new Vector(31,32,0)
+      s.depth = 1
+      s.display0 = elems
+      s
+    }
+  }
+
+  def appendBack[B>:A](value: B): Vector[B] = {
+//    //println("------- append " + value)
+//    debug()
+    if (endIndex != startIndex) {
+      var blockIndex = endIndex & ~31
+      var lo = endIndex & 31
+
+      if (endIndex == blockIndex) {
+        val shift = startIndex & ~((1<<5*(depth-1))-1)
+        val shiftBlocks = startIndex >>> 5*(depth-1)
+
+        //println("----- appendBack " + value + " at " + endIndex + " reached block end")
+
+        if (shift != 0) {
+          debug
+          //println("shifting left by " + shiftBlocks + " at level " + (depth-1) + " (had "+startIndex+" free space)")
+          if (depth > 1) {
+            val newBlockIndex = blockIndex - shift
+            val newFocus = focus - shift
+            val s = new Vector(startIndex - shift, endIndex + 1 - shift, newBlockIndex)
+            s.initFrom(this)
+            s.shiftTopLevel(shiftBlocks, 0) // shift left by n blocks
+            s.debug
+            s.gotoFreshPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+            s.display0(lo) = value.asInstanceOf[AnyRef]
+            s.debug
+            //assert(depth == s.depth)
+            s
+          } else {
+            val newBlockIndex = blockIndex - 32
+            val newFocus = focus
+
+            //assert(newBlockIndex == 0)
+            //assert(newFocus == 0)
+
+            val s = new Vector(startIndex - shift, endIndex + 1 - shift, newBlockIndex)
+            s.initFrom(this)
+            s.shiftTopLevel(shiftBlocks, 0) // shift right by n elements
+            s.gotoPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+            s.display0(32 - shift) = value.asInstanceOf[AnyRef]
+            s.debug
+            s
+          }
+        } else {
+          val newBlockIndex = blockIndex
+          val newFocus = focus
+
+          val s = new Vector(startIndex, endIndex + 1, newBlockIndex)
+          s.initFrom(this)
+          s.gotoFreshPosClean(newFocus, newBlockIndex, newFocus ^ newBlockIndex)
+          s.display0(lo) = value.asInstanceOf[AnyRef]
+          //assert(s.depth == depth+1) might or might not create new level!
+          if (s.depth == depth+1) {
+            //println("creating new level " + s.depth + " (had "+0+" free space)")
+            s.debug
+          }
+          s
+        }
+      } else {
+//        //println("will make writable block (from "+focus+") at: " + blockIndex)
+        val s = new Vector(startIndex, endIndex + 1, blockIndex)
+        s.initFrom(this)
+        s.gotoPosClean(focus, blockIndex, focus ^ blockIndex)
+        s.display0(lo) = value.asInstanceOf[AnyRef]
+        s
+      }
+    } else {
+      val elems = new Array[AnyRef](32)
+      elems(0) = value.asInstanceOf[AnyRef]
+      val s = new Vector(0,1,0)
+      s.depth = 1
+      s.display0 = elems
+      s
+    }
+  }
+
 }
 
-/**
- * @since 2.8
- */
-object Vector extends SeqFactory[Vector] {
-  // todo: insert better vector implementation here
-  @serializable @SerialVersionUID(7129304555082767876L)
-  class Impl[A](buf: ArrayBuffer[A]) extends Vector[A] {
-    def length = buf.length
-    def apply(idx: Int) = buf.apply(idx)
+
+final class VectorIterator[+A](_startIndex: Int, _endIndex: Int) extends Iterator[A] with VectorPointer[A @uncheckedVariance] {
+
+  private var blockIndex: Int = _startIndex & ~31
+  private var lo: Int = _startIndex & 31
+  private var endIndex: Int = _endIndex
+
+  private var endLo = Math.min(endIndex - blockIndex, 32)
+
+  def hasNext = _hasNext
+
+  private var _hasNext = blockIndex + lo < endIndex
+
+  def next(): A = {
+    if (!_hasNext) throw new NoSuchElementException("reached iterator end")
+
+    val res = display0(lo).asInstanceOf[A]
+    lo += 1
+
+    if (lo == endLo) {
+      if (blockIndex + lo < endIndex) {
+        val newBlockIndex = blockIndex+32
+        gotoNextBlockStart(newBlockIndex, blockIndex ^ newBlockIndex)
+
+        blockIndex = newBlockIndex
+        endLo = Math.min(endIndex - blockIndex, 32)
+        lo = 0
+      } else {
+        _hasNext = false
+      }
+    }
+
+    res
+  }
+
+  // TODO: take
+  // TODO: drop
+}
+
+
+final class VectorBuilder[A]() extends Builder[A,Vector[A]] with VectorPointer[A @uncheckedVariance] {
+
+  display0 = new Array[AnyRef](32)
+  depth = 1
+
+  var blockIndex = 0
+  var lo = 0
+
+  def += (elem: A): this.type = {
+    if (lo == 32) {
+      val newBlockIndex = blockIndex+32
+      gotoNextBlockStartClean(newBlockIndex, blockIndex ^ newBlockIndex)
+      blockIndex = newBlockIndex
+      lo = 0
+    }
+    display0(lo) = elem.asInstanceOf[AnyRef]
+    lo += 1
+    this
+  }
+
+  def result: Vector[A] = {
+    val s = new Vector[A](0, blockIndex + lo, 0) // TODO: should focus front or back?
+    s.initFrom(this)
+    if (depth > 1) s.gotoPos(0, blockIndex + lo)
+    s
+  }
+
+  def clear: Unit = {
+    display0 = new Array[AnyRef](32)
+    depth = 1
+    blockIndex = 0
+    lo = 0
   }
-  implicit def builderFactory[A]: BuilderFactory[A, Vector[A], Coll] =
-    new VirtualBuilderFactory[A]
-  def newBuilder[A]: Builder[A, Vector[A]] =
-    new ArrayBuffer[A] mapResult (buf => new Impl(buf))
 }