javax.media.j3d.J3dHash Maven / Gradle / Ivy
/*
* Copyright 2013 Harvey Harrison
*
* 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));
}
}