/*-
 * #%L
 * Fiji distribution of ImageJ for the life sciences.
 * %%
 * Copyright (C) 2007 - 2017 Fiji developers.
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 2 of the
 * License, or (at your option) any later version.
 * 
 * This program 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 for more details.
 * 
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-2.0.html>.
 * #L%
 */
package spim.vecmath;

/*
 * Copyright 2013 Harvey Harrison <harvey.harrison@gmail.com>
 *
 * 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).
 */

/**
 * 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 ) );
	}
}