j3dcore: add a hash mixing helper for the Java3D way of mixing double values

Signed-off-by: Harvey Harrison <[email protected]>

5 files changed, 63 insertions, 27 deletions

diff --git a/src/classes/share/javax/media/j3d/BoundingBox.java b/src/classes/share/javax/media/j3d/BoundingBox.java
index 8d0cc1c..4595ced 100644
--- a/src/classes/share/javax/media/j3d/BoundingBox.java
+++ b/src/classes/share/javax/media/j3d/BoundingBox.java
@@ -31,8 +31,6 @@ import javax.vecmath.Point4d;
 import javax.vecmath.Vector3d;
 import javax.vecmath.Vector4d;
 
-import com.sun.j3d.internal.HashCodeUtil;
-
 /**
  *  This class defines an axis aligned bounding box which is used for
  *  bounding regions.
@@ -399,13 +397,13 @@ public void setUpper(Point3d p1) {
      */
     public int hashCode() {
 	long bits = 1L;
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(lower.x);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(lower.y);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(lower.z);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(upper.x);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(upper.y);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(upper.z);
-	return (int) (bits ^ (bits >> 32));
+	bits = J3dHash.mixDoubleBits(bits, lower.x);
+	bits = J3dHash.mixDoubleBits(bits, lower.y);
+	bits = J3dHash.mixDoubleBits(bits, lower.z);
+	bits = J3dHash.mixDoubleBits(bits, upper.x);
+	bits = J3dHash.mixDoubleBits(bits, upper.y);
+	bits = J3dHash.mixDoubleBits(bits, upper.z);
+	return J3dHash.finish(bits);
     }
 
 
diff --git a/src/classes/share/javax/media/j3d/BoundingPolytope.java b/src/classes/share/javax/media/j3d/BoundingPolytope.java
index ab74ae6..4dc6844 100644
--- a/src/classes/share/javax/media/j3d/BoundingPolytope.java
+++ b/src/classes/share/javax/media/j3d/BoundingPolytope.java
@@ -31,8 +31,6 @@ import javax.vecmath.Point4d;
 import javax.vecmath.Vector3d;
 import javax.vecmath.Vector4d;
 
-import com.sun.j3d.internal.HashCodeUtil;
-
 /**
  * A BoundingPolytope defines a polyhedral bounding region using the
  * intersection of four or more half spaces.  The region defined by a
@@ -531,13 +529,13 @@ public class BoundingPolytope extends Bounds {
 	long bits = 1L;
 
 	for (int i = 0; i < planes.length; i++) {
-	    bits = 31L * bits + HashCodeUtil.doubleToLongBits(planes[i].x);
-	    bits = 31L * bits + HashCodeUtil.doubleToLongBits(planes[i].y);
-	    bits = 31L * bits + HashCodeUtil.doubleToLongBits(planes[i].z);
-	    bits = 31L * bits + HashCodeUtil.doubleToLongBits(planes[i].w);
+		bits = J3dHash.mixDoubleBits(bits, planes[i].x);
+		bits = J3dHash.mixDoubleBits(bits, planes[i].y);
+		bits = J3dHash.mixDoubleBits(bits, planes[i].z);
+		bits = J3dHash.mixDoubleBits(bits, planes[i].w);
 	}
 
-	return (int) (bits ^ (bits >> 32));
+	return J3dHash.finish(bits);
     }
 
 
diff --git a/src/classes/share/javax/media/j3d/BoundingSphere.java b/src/classes/share/javax/media/j3d/BoundingSphere.java
index 94a1b59..ff9bf66 100644
--- a/src/classes/share/javax/media/j3d/BoundingSphere.java
+++ b/src/classes/share/javax/media/j3d/BoundingSphere.java
@@ -31,8 +31,6 @@ import javax.vecmath.Point4d;
 import javax.vecmath.Vector3d;
 import javax.vecmath.Vector4d;
 
-import com.sun.j3d.internal.HashCodeUtil;
-
 /**
  * This class defines a spherical bounding region which is defined by a
  * center point and a radius.
@@ -410,11 +408,11 @@ public void setCenter(Point3d center) {
      */
     public int hashCode() {
 	long bits = 1L;
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(radius);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(center.x);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(center.y);
-	bits = 31L * bits + HashCodeUtil.doubleToLongBits(center.z);
-	return (int) (bits ^ (bits >> 32));
+	bits = J3dHash.mixDoubleBits(bits, radius);
+	bits = J3dHash.mixDoubleBits(bits, center.x);
+	bits = J3dHash.mixDoubleBits(bits, center.y);
+	bits = J3dHash.mixDoubleBits(bits, center.z);
+	return J3dHash.finish(bits);
     }
 
 
diff --git a/src/classes/share/javax/media/j3d/J3dHash.java b/src/classes/share/javax/media/j3d/J3dHash.java
new file mode 100644
index 0000000..5db0437
--- /dev/null
+++ b/src/classes/share/javax/media/j3d/J3dHash.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2013 Harvey Harrison <[email protected]>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ */
+package javax.media.j3d;
+
+/**
+ * A Utility class wrapping the approach used to hash double values in Java3D
+ */
+class J3dHash {
+
+// prevent an instance from actually being created
+private J3dHash() {}
+
+/**
+ * Mix the given double into the provided long hash.
+ */
+static final long mixDoubleBits(long hash, double d) {
+	hash *= 31L;
+	// Treat 0.0d and -0.0d the same (all zero bits)
+	if (d == 0.0d)
+		return hash;
+
+	return hash + Double.doubleToLongBits(d);
+}
+
+/**
+ * Return an integer hash from a long by mixing it with itself.
+ */
+static final int finish(long hash) {
+	return (int)(hash ^ (hash >> 32));
+}
+}
diff --git a/src/classes/share/javax/media/j3d/Transform3D.java b/src/classes/share/javax/media/j3d/Transform3D.java
index 38414d9..99296f3 100644
--- a/src/classes/share/javax/media/j3d/Transform3D.java
+++ b/src/classes/share/javax/media/j3d/Transform3D.java
@@ -44,8 +44,6 @@ import javax.vecmath.Vector3f;
 import javax.vecmath.Vector4d;
 import javax.vecmath.Vector4f;
 
-import com.sun.j3d.internal.HashCodeUtil;
-
 /**
  * A generalized transform object represented internally as a 4x4
  * double-precision floating point matrix.  The mathematical
@@ -4089,9 +4087,9 @@ public class Transform3D {
 	long bits = 1L;
 
 	for (int i = 0; i < 16; i++) {
-	    bits = 31L * bits + HashCodeUtil.doubleToLongBits(mat[i]);
+		bits = J3dHash.mixDoubleBits(bits, mat[i]);
 	}
-	return (int) (bits ^ (bits >> 32));
+	return J3dHash.finish(bits);
     }