diff options
| -rw-r--r-- | src/library/scala/runtime/BoxesRunTime.java | 61 | ||||
| -rw-r--r-- | src/library/scala/runtime/ScalaRunTime.scala | 30 | ||||
| -rw-r--r-- | test/files/run/hashCodeScalaRunTime.scala (renamed from test/files/run/hashCodeBoxesRunTime.scala) | 10 | ||||
| -rw-r--r-- | test/files/run/hashhash.scala | 8 |
4 files changed, 41 insertions, 68 deletions
diff --git a/src/library/scala/runtime/BoxesRunTime.java b/src/library/scala/runtime/BoxesRunTime.java index 258a176671..0df196b2a6 100644 --- a/src/library/scala/runtime/BoxesRunTime.java +++ b/src/library/scala/runtime/BoxesRunTime.java @@ -203,67 +203,6 @@ public final class BoxesRunTime } } - /** Hashcode algorithm is driven by the requirements imposed - * by primitive equality semantics, namely that equal objects - * have equal hashCodes. The first priority are the integral/char - * types, which already have the same hashCodes for the same - * values except for Long. So Long's hashCode is altered to - * conform to Int's for all values in Int's range. - * - * Float is problematic because it's far too small to hold - * all the Ints, so for instance Int.MaxValue.toFloat claims - * to be == to each of the largest 64 Ints. There is no way - * to preserve equals/hashCode alignment without compromising - * the hashCode distribution, so Floats are only guaranteed - * to have the same hashCode for whole Floats in the range - * Short.MinValue to Short.MaxValue (2^16 total.) - * - * Double has its hashCode altered to match the entire Int range, - * but is not guaranteed beyond that. (But could/should it be? - * The hashCode is only 32 bits so this is a more tractable - * issue than Float's, but it might be better simply to exclude it.) - * - * Note: BigInt and BigDecimal, being arbitrary precision, could - * be made consistent with all other types for the Int range, but - * as yet have not. - * - * Note: Among primitives, Float.NaN != Float.NaN, but the boxed - * verisons are equal. This still needs reconciliation. - */ - public static int hashFromLong(java.lang.Long n) { - int iv = n.intValue(); - if (iv == n.longValue()) return iv; - else return n.hashCode(); - } - public static int hashFromDouble(java.lang.Double n) { - int iv = n.intValue(); - double dv = n.doubleValue(); - if (iv == dv) return iv; - - long lv = n.longValue(); - if (lv == dv) return java.lang.Long.valueOf(lv).hashCode(); - else return n.hashCode(); - } - public static int hashFromFloat(java.lang.Float n) { - int iv = n.intValue(); - float fv = n.floatValue(); - if (iv == fv) return iv; - - long lv = n.longValue(); - if (lv == fv) return java.lang.Long.valueOf(lv).hashCode(); - else return n.hashCode(); - } - public static int hashFromNumber(java.lang.Number n) { - if (n instanceof java.lang.Long) return hashFromLong((java.lang.Long)n); - else if (n instanceof java.lang.Double) return hashFromDouble((java.lang.Double)n); - else if (n instanceof java.lang.Float) return hashFromFloat((java.lang.Float)n); - else return n.hashCode(); - } - public static int hashFromObject(Object a) { - if (a instanceof Number) return hashFromNumber((Number)a); - else return a.hashCode(); - } - private static int unboxCharOrInt(Object arg1, int code) { if (code == CHAR) return ((java.lang.Character) arg1).charValue(); diff --git a/src/library/scala/runtime/ScalaRunTime.scala b/src/library/scala/runtime/ScalaRunTime.scala index a04fd23710..b3d99aa8d8 100644 --- a/src/library/scala/runtime/ScalaRunTime.scala +++ b/src/library/scala/runtime/ScalaRunTime.scala @@ -233,12 +233,39 @@ object ScalaRunTime { // // Note that these are the implementations called by ##, so they // must not call ## themselves. + // + // Hashcode algorithm is driven by the requirements imposed + // by primitive equality semantics, namely that equal objects + // have equal hashCodes. The first priority are the integral/char + // types, which already have the same hashCodes for the same + // values except for Long. So Long's hashCode is altered to + // conform to Int's for all values in Int's range. + // + // Float is problematic because it's far too small to hold + // all the Ints, so for instance Int.MaxValue.toFloat claims + // to be == to each of the largest 64 Ints. There is no way + // to preserve equals/hashCode alignment without compromising + // the hashCode distribution, so Floats are only guaranteed + // to have the same hashCode for whole Floats in the range + // Short.MinValue to Short.MaxValue (2^16 total.) + // + // Double has its hashCode altered to match the entire Int range, + // but is not guaranteed beyond that. (But could/should it be? + // The hashCode is only 32 bits so this is a more tractable + // issue than Float's, but it might be better simply to exclude it.) + // + // Note: BigInt and BigDecimal, being arbitrary precision, could + // be made consistent with all other types for the Int range, but + // as yet have not. + // + // Note: Among primitives, Float.NaN != Float.NaN, but the boxed + // verisons are equal. This still needs reconciliation. @inline def hash(x: Any): Int = x match { case null => 0 + case x: Long => hash(x) case x: Double => hash(x) case x: Float => hash(x) - case x: java.lang.Number => hash(x) case _ => x.hashCode } @@ -266,7 +293,6 @@ object ScalaRunTime { val high = (lv >>> 32).toInt low ^ (high + lowSign) } - @inline def hash(x: Number): Int = runtime.BoxesRunTime.hashFromNumber(x) // The remaining overloads are here for completeness, but the compiler // inlines these definitions directly so they're not generally used. diff --git a/test/files/run/hashCodeBoxesRunTime.scala b/test/files/run/hashCodeScalaRunTime.scala index 081a73376e..e352af95f1 100644 --- a/test/files/run/hashCodeBoxesRunTime.scala +++ b/test/files/run/hashCodeScalaRunTime.scala @@ -1,23 +1,23 @@ -// This only tests direct access to the methods in BoxesRunTime, +// This only tests direct access to the methods in ScalaRunTime, // not the whole scheme. object Test { import java.{ lang => jl } - import scala.runtime.BoxesRunTime.{ hashFromNumber, hashFromObject } + import scala.runtime.ScalaRunTime.{ hash } def allSame[T](xs: List[T]) = assert(xs.distinct.size == 1, "failed: " + xs) def mkNumbers(x: Int): List[Number] = List(x.toByte, x.toShort, x, x.toLong, x.toFloat, x.toDouble) - def testLDF(x: Long) = allSame(List[Number](x, x.toDouble, x.toFloat) map hashFromNumber) + def testLDF(x: Long) = allSame(List[Number](x, x.toDouble, x.toFloat) map hash) def main(args: Array[String]): Unit = { List(Byte.MinValue, -1, 0, 1, Byte.MaxValue) foreach { n => - val hashes = mkNumbers(n) map hashFromNumber + val hashes = mkNumbers(n) map hash allSame(hashes) if (n >= 0) { - val charCode = hashFromObject(n.toChar: Character) + val charCode = hash(n.toChar: Character) assert(charCode == hashes.head) } } diff --git a/test/files/run/hashhash.scala b/test/files/run/hashhash.scala index dc31df8cfa..f9fc067398 100644 --- a/test/files/run/hashhash.scala +++ b/test/files/run/hashhash.scala @@ -9,7 +9,15 @@ object Test { val x = (BigInt(1) << 64).toDouble val y: Any = x + val f: Float = x.toFloat + val jn: java.lang.Number = x + val jf: java.lang.Float = x.toFloat + val jd: java.lang.Double = x assert(x.## == y.##, ((x, y))) + assert(x.## == f.##, ((x, f))) + assert(x.## == jn.##, ((x, jn))) + assert(x.## == jf.##, ((x, jf))) + assert(x.## == jd.##, ((x, jd))) } } |