mirror of
https://github.com/VolmitSoftware/Iris.git
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104 lines
4.0 KiB
Java
104 lines
4.0 KiB
Java
/*
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* $RCSfile$
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*
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* Copyright 2004-2008 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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* $Revision: 127 $
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* $Date: 2008-02-28 21:18:51 +0100 (Thu, 28 Feb 2008) $
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* $State$
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*/
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package com.volmit.iris.util;
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/**
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* Utility vecmath class used when computing the hash code for vecmath
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* objects containing float or double values. This fixes Issue 36.
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*/
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class VecMathUtil {
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/**
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* Returns the representation of the specified floating-point
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* value according to the IEEE 754 floating-point "single format"
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* bit layout, after first mapping -0.0 to 0.0. This method is
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* identical to Float.floatToIntBits(float) except that an integer
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* value of 0 is returned for a floating-point value of
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* -0.0f. This is done for the purpose of computing a hash code
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* that satisfies the contract of hashCode() and equals(). The
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* equals() method in each vecmath class does a pair-wise "=="
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* test on each floating-point field in the class (e.g., x, y, and
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* z for a Tuple3f). Since 0.0f == -0.0f returns true,
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* we must also return the same hash code for two objects, one of
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* which has a field with a value of -0.0f and the other of which
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* has a cooresponding field with a value of 0.0f.
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*
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* @param f an input floating-point number
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* @return the integer bits representing that floating-point
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* number, after first mapping -0.0f to 0.0f
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*/
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static int floatToIntBits(float f) {
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// Check for +0 or -0
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if (f == 0.0f) {
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return 0;
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}
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else {
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return Float.floatToIntBits(f);
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}
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}
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/**
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* Returns the representation of the specified floating-point
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* value according to the IEEE 754 floating-point "double format"
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* bit layout, after first mapping -0.0 to 0.0. This method is
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* identical to Double.doubleToLongBits(double) except that an
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* integer value of 0L is returned for a floating-point value of
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* -0.0. This is done for the purpose of computing a hash code
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* that satisfies the contract of hashCode() and equals(). The
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* equals() method in each vecmath class does a pair-wise "=="
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* test on each floating-point field in the class (e.g., x, y, and
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* z for a Tuple3d). Since 0.0 == -0.0 returns true, we
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* must also return the same hash code for two objects, one of
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* which has a field with a value of -0.0 and the other of which
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* has a cooresponding field with a value of 0.0.
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*
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* @param d an input double precision floating-point number
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* @return the integer bits representing that floating-point
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* number, after first mapping -0.0f to 0.0f
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*/
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static long doubleToLongBits(double d) {
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// Check for +0 or -0
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if (d == 0.0) {
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return 0L;
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}
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else {
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return Double.doubleToLongBits(d);
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}
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}
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/**
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* Do not construct an instance of this class.
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*/
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private VecMathUtil() {
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}
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}
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