diff options
| -rw-r--r-- | src/library/scala/collection/convert/Wrappers.scala | 10 | ||||
| -rw-r--r-- | test/files/run/t5880.scala | 41 |
2 files changed, 49 insertions, 2 deletions
diff --git a/src/library/scala/collection/convert/Wrappers.scala b/src/library/scala/collection/convert/Wrappers.scala index b1b48b760f..6c66ac6c4d 100644 --- a/src/library/scala/collection/convert/Wrappers.scala +++ b/src/library/scala/collection/convert/Wrappers.scala @@ -171,7 +171,13 @@ private[collection] trait Wrappers { var prev : Option[A] = None def hasNext = ui.hasNext - + + def improve(hc: Int) = { + var i = hc * 0x9e3775cd + i = java.lang.Integer.reverseBytes(i) + i * 0x9e3775c + } + def next() = { val (k, v) = ui.next prev = Some(k) @@ -179,7 +185,7 @@ private[collection] trait Wrappers { def getKey = k def getValue = v def setValue(v1 : B) = self.put(k, v1) - override def hashCode = k.hashCode + v.hashCode + override def hashCode = improve(k.hashCode) + (improve(v.hashCode) << 16) override def equals(other: Any) = other match { case e: ju.Map.Entry[_, _] => k == e.getKey && v == e.getValue case _ => false diff --git a/test/files/run/t5880.scala b/test/files/run/t5880.scala new file mode 100644 index 0000000000..08cd0d6bf8 --- /dev/null +++ b/test/files/run/t5880.scala @@ -0,0 +1,41 @@ + + +import scala.collection.JavaConversions._ + + + +object Test { + + def main(args:Array[String]) = { + val tests = 5000 + val jm: java.util.Map[Int, Int] = scala.collection.mutable.Map((0 until tests) zip (0 until tests).reverse: _*) + val es = jm.entrySet() + val it = es.iterator + + // chi square test + val groups = 10 + val hits = new Array[Int](groups) + def hit(hc: Int) { + val bucket = math.abs(hc) / (Int.MaxValue / groups) + hits(bucket) += 1 + } + def expected = tests / groups + def Dstat = { + val diffs = for (i <- 0 until groups) yield math.abs(hits(i) - expected) + diffs.sum.toDouble / expected + } + def ChiSquare = { + val diffs = for (i <- 0 until groups) yield (hits(i) - expected) * (hits(i) - expected) + diffs.sum.toDouble / expected + } + + while (it.hasNext) { + val x = it.next() + hit(x.##) + } + // println(hits.toBuffer) + // println(ChiSquare) + assert(ChiSquare < 2.0) + } + +} |