new version of collection libraries

1 files changed, 164 insertions, 0 deletions

diff --git a/src/library/scalax/collection/mutable/FlatHashTable.scala b/src/library/scalax/collection/mutable/FlatHashTable.scala
new file mode 100644
index 0000000000..c8fe2cede3
--- /dev/null
+++ b/src/library/scalax/collection/mutable/FlatHashTable.scala
@@ -0,0 +1,164 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2009, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+// $Id: FlatHashTable.scala 16893 2009-01-13 13:09:22Z cunei $
+
+package scalax.collection.mutable
+
+trait FlatHashTable[A] {
+
+  /** The load factor for the hash table; must be < 500 (0.5)
+   */
+  protected def loadFactor: Int = 450
+  protected final def loadFactorDenum = 1000
+
+  /** The initial size of the hash table.
+   */
+  protected def initialSize: Int = 16
+
+  private final val tableDebug = false
+
+  /** The actual hash table.
+   */
+  protected var table: scala.Array[AnyRef] =
+    if (initialSize == 0) null else new scala.Array(initialSize)
+
+  /** The number of mappings contained in this hash table.
+   */
+  protected var tableSize = 0
+
+  /** The next size value at which to resize (capacity * load factor).
+   */
+  protected var threshold: Int = newThreshold(initialSize)
+
+  /** Returns the number of entires in this hash table.
+   */
+  def size: Int = tableSize
+
+  def findEntry(elem: A): Option[A] = {
+    var h = index(elemHashCode(elem))
+    var entry = table(h)
+    while (null != entry && entry != elem) {
+      h = (h + 1) % table.length
+      entry = table(h)
+    }
+    if (null == entry) None else Some(entry.asInstanceOf[A])
+  }
+
+  def containsEntry(elem: A): Boolean = {
+    var h = index(elemHashCode(elem))
+    var entry = table(h)
+    while (null != entry && entry != elem) {
+      h = (h + 1) % table.length
+      entry = table(h)
+    }
+    null != entry
+  }
+
+  def addEntry(elem: A) : Boolean = {
+    var h = index(elemHashCode(elem))
+    var entry = table(h)
+    while (null != entry) {
+      if (entry == elem) return false
+      h = (h + 1) % table.length
+      entry = table(h)
+    }
+    table(h) = elem.asInstanceOf[AnyRef]
+    tableSize = tableSize + 1
+    if (tableSize >= threshold) growTable()
+    true
+  }
+
+  def removeEntry(elem: A) : Option[A] = {
+    if (tableDebug) checkConsistent()
+    def precedes(i: Int, j: Int) = {
+      val d = table.length >> 1
+      if (i <= j) j - i < d
+      else i - j > d
+    }
+    var h = index(elemHashCode(elem))
+    var entry = table(h)
+    while (null != entry) {
+      if (entry == elem) {
+        var h0 = h
+        var h1 = (h0 + 1) % table.length
+        while (null != table(h1)) {
+          val h2 = index(elemHashCode(table(h1).asInstanceOf[A]))
+          //Console.println("shift at "+h1+":"+table(h1)+" with h2 = "+h2+"? "+(h2 != h1)+precedes(h2, h0)+table.length)
+          if (h2 != h1 && precedes(h2, h0)) {
+            //Console.println("shift "+h1+" to "+h0+"!")
+            table(h0) = table(h1)
+            h0 = h1
+          }
+          h1 = (h1 + 1) % table.length
+        }
+        table(h0) = null
+        tableSize -= 1
+        if (tableDebug) checkConsistent()
+        return Some(entry.asInstanceOf[A])
+      }
+      h = (h + 1) % table.length
+      entry = table(h)
+    }
+    None
+  }
+
+  def elements = new Iterator[A] {
+    private var i = 0
+    def hasNext: Boolean = {
+      while (i < table.length && (null == table(i))) i += 1;
+      i < table.length
+    }
+    def next(): A =
+      if (hasNext) { i += 1; table(i - 1).asInstanceOf[A] }
+      else Iterator.empty.next
+  }
+
+  private def growTable() {
+    val oldtable = table
+    table = new scala.Array[AnyRef](table.length * 2)
+    tableSize = 0
+    threshold = newThreshold(table.length)
+    var i = 0
+    while (i < oldtable.length) {
+      val entry = oldtable(i)
+      if (null != entry) addEntry(entry.asInstanceOf[A])
+      i += 1
+    }
+    if (tableDebug) checkConsistent()
+  }
+
+  private def checkConsistent() {
+    for (i <- 0 until table.length)
+      if (table(i) != null && !containsEntry(table(i).asInstanceOf[A]))
+        assert(false, i+" "+table(i)+" "+table.toString)
+  }
+
+  protected def elemHashCode(elem: A) = elem.hashCode()
+
+  protected final def improve(hcode: Int) = {
+    var h: Int = hcode + ~(hcode << 9)
+    h = h ^ (h >>> 14)
+    h = h + (h << 4)
+    h ^ (h >>> 10)
+  }
+
+  protected final def index(hcode: Int) = improve(hcode) & (table.length - 1)
+
+  private def newThreshold(size: Int) = {
+    val lf = loadFactor
+    assert(lf < (loadFactorDenum / 2), "loadFactor too large; must be < 0.5")
+    (size.toLong * lf / loadFactorDenum ).toInt
+  }
+
+  protected def clear() {
+    var i = table.length - 1
+    while (i >= 0) { table(i) = null; i -= 1 }
+    tableSize = 0
+  }
+}