/*-
 * #%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 2004-2008 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * 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).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

/**
 * Utility vecmath class used when computing the hash code for vecmath objects
 * containing float or double values. This fixes Issue 36.
 */
class VecMathUtil
{
	/**
	 * Do not construct an instance of this class.
	 */
	private VecMathUtil()
	{
	}

	static final long hashLongBits( long hash, long l )
	{
		hash *= 31L;
		return hash + l;
	}

	static final long hashFloatBits( long hash, float f )
	{
		hash *= 31L;
		// Treat 0.0d and -0.0d the same (all zero bits)
		if ( f == 0.0f )
			return hash;

		return hash + Float.floatToIntBits( f );
	}

	static final long hashDoubleBits( 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 hashFinish( long hash )
	{
		return (int) ( hash ^ ( hash >> 32 ) );
	}
}