From 47ff60552398b09a8b757345cd56f12091d97b92 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Mon, 9 Nov 2009 10:35:54 +0000
Subject: fast path equals and hash methods.

---
 src/library/scala/Predef.scala               |  5 +++
 src/library/scala/runtime/BoxesRunTime.java  | 56 +++++++++++++++++++---------
 src/library/scala/runtime/ScalaRunTime.scala |  7 ++++
 3 files changed, 51 insertions(+), 17 deletions(-)

(limited to 'src/library')

diff --git a/src/library/scala/Predef.scala b/src/library/scala/Predef.scala
index cab32b0595..c3f6ad9eff 100644
--- a/src/library/scala/Predef.scala
+++ b/src/library/scala/Predef.scala
@@ -91,6 +91,11 @@ object Predef extends LowPriorityImplicits {
 
   def currentThread = java.lang.Thread.currentThread()
 
+  // hashcode and equality -------------------------------------------------
+
+  @inline def hash(x: Any): Int =
+    if (x.isInstanceOf[Number]) (x.asInstanceOf[Number]).intValue else x.hashCode
+
   // errors and asserts -------------------------------------------------
 
   def error(message: String): Nothing = throw new RuntimeException(message)
diff --git a/src/library/scala/runtime/BoxesRunTime.java b/src/library/scala/runtime/BoxesRunTime.java
index 3e75cb213e..b5df9d8ce8 100644
--- a/src/library/scala/runtime/BoxesRunTime.java
+++ b/src/library/scala/runtime/BoxesRunTime.java
@@ -139,6 +139,45 @@ public class BoxesRunTime
 
     /* COMPARISON ... COMPARISON ... COMPARISON ... COMPARISON ... COMPARISON ... COMPARISON */
 
+    // That's the method we should use from now on.
+    public static boolean equals(Object x, Object y) {
+        if (x instanceof Number) {
+            Number xn = (Number)x;
+            if (y instanceof Number) {
+                Number yn = (Number)y;
+                if ((xn instanceof Double) || (yn instanceof Double))
+                    return xn.doubleValue() == yn.doubleValue();
+                if ((xn instanceof Float) || (yn instanceof Float))
+                    return xn.floatValue() == yn.floatValue();
+                if ((xn instanceof Long) || (yn instanceof Long))
+                    return xn.longValue() == yn.longValue();
+                return xn.intValue() == yn.intValue();
+            }
+            if (y instanceof Character)
+                return equalsNumChar(xn, (Character)y);
+        } else if (x instanceof Character) {
+            Character xc = (Character)x;
+            if (y instanceof Character)
+                return (xc.charValue() == ((Character)y).charValue());
+            if (y instanceof Number)
+                return equalsNumChar((Number)y, xc);
+        } else if (x == null) {
+            return y == null;
+        }
+        return x.equals(y);
+    }
+
+    private static boolean equalsNumChar(Number x, Character y) {
+        char ch = y.charValue();
+        if (x instanceof Double)
+            return x.doubleValue() == ch;
+        if (x instanceof Float)
+            return x.floatValue() == ch;
+        if (x instanceof Long)
+            return x.longValue() == ch;
+        return x.intValue() == ch;
+    }
+
     private static boolean equalsBonusLogicFromScala27(Object a, Object b) {
         if (a instanceof Number || a instanceof Character || b instanceof Number || b instanceof Character) {
             int acode = typeCode(a);
@@ -188,23 +227,6 @@ public class BoxesRunTime
       }
     }
 
-    /** The current equals method. **/
-    public static boolean equals(Object a, Object b) {
-        if (a == null || b == null)
-            return a == b;
-
-        verifyEqEq(a, b,
-          (Equality.dieOnBoxedCompare || Equality.dieOnBoxedCompareIfValuesAreEqual),
-          (Equality.warnOnBoxedCompareIfValuesAreEqual || Equality.dieOnBoxedCompareIfValuesAreEqual)
-        );
-
-        if (a.equals(b))
-            return true;
-
-        if (Equality.use28Semantics) return false;
-        else return equalsBonusLogicFromScala27(a, b);
-    }
-
 /* OPERATORS ... OPERATORS ... OPERATORS ... OPERATORS ... OPERATORS ... OPERATORS ... OPERATORS ... OPERATORS */
 
     /** arg1 + arg2 */
diff --git a/src/library/scala/runtime/ScalaRunTime.scala b/src/library/scala/runtime/ScalaRunTime.scala
index 4541c0147c..a93ff61a41 100644
--- a/src/library/scala/runtime/ScalaRunTime.scala
+++ b/src/library/scala/runtime/ScalaRunTime.scala
@@ -120,6 +120,13 @@ object ScalaRunTime {
     code
   }
 
+  /** Fast path equality method for inlining; used when -optimise is set.
+   */
+  @inline def inlinedEquals(x: Object, y: Object): Boolean =
+    if (x eq null) y eq null
+    else if (x.isInstanceOf[Number] || x.isInstanceOf[Character]) BoxesRunTime.equals(x, y)
+    else x.equals(y)
+
   def _equals(x: Product, y: Any): Boolean = y match {
     case y1: Product if x.productArity == y1.productArity =>
       val arity = x.productArity
-- 
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