Mega Code Archive
Compares two floats for order
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* <p>Provides extra functionality for Java Number classes.</p>
*
* @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
* @author Stephen Colebourne
* @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
* @author Eric Pugh
* @author Phil Steitz
* @author Matthew Hawthorne
* @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
* @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
* @since 2.0
* @version $Id: NumberUtils.java 609475 2008-01-06 23:58:59Z bayard $
*/
public class Main {
/**
* <p>Compares two floats for order.</p>
*
* <p>This method is more comprehensive than the standard Java greater than,
* less than and equals operators.</p>
* <ul>
* <li>It returns <code>-1</code> if the first value is less than the second.
* <li>It returns <code>+1</code> if the first value is greater than the second.
* <li>It returns <code>0</code> if the values are equal.
* </ul>
*
* <p> The ordering is as follows, largest to smallest:
* <ul>
* <li>NaN
* <li>Positive infinity
* <li>Maximum float
* <li>Normal positive numbers
* <li>+0.0
* <li>-0.0
* <li>Normal negative numbers
* <li>Minimum float (<code>-Float.MAX_VALUE</code>)
* <li>Negative infinity
* </ul>
*
* <p>Comparing <code>NaN</code> with <code>NaN</code> will return
* <code>0</code>.</p>
*
* @param lhs the first <code>float</code>
* @param rhs the second <code>float</code>
* @return <code>-1</code> if lhs is less, <code>+1</code> if greater,
* <code>0</code> if equal to rhs
*/
public static int compare(float lhs, float rhs) {
if (lhs < rhs) {
return -1;
}
if (lhs > rhs) {
return +1;
}
//Need to compare bits to handle 0.0 == -0.0 being true
// compare should put -0.0 < +0.0
// Two NaNs are also == for compare purposes
// where NaN == NaN is false
int lhsBits = Float.floatToIntBits(lhs);
int rhsBits = Float.floatToIntBits(rhs);
if (lhsBits == rhsBits) {
return 0;
}
//Something exotic! A comparison to NaN or 0.0 vs -0.0
//Fortunately NaN's int is > than everything else
//Also negzeros bits < poszero
//NAN: 2143289344
//MAX: 2139095039
//NEGZERO: -2147483648
if (lhsBits < rhsBits) {
return -1;
} else {
return +1;
}
}
}
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