/*
* Copyright 2005-2010 Roger Kapsi
*
* Licensed 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.
*/
package org.ardverk.collection;
import java.io.Serializable;
/**
* A {@link KeyAnalyzer} for {@link Long}s
*/
public class LongKeyAnalyzer extends AbstractKeyAnalyzer<Long> implements Serializable {
private static final long serialVersionUID = -7611788114037795486L;
/**
* A singleton instance of {@link LongKeyAnalyzer}
*/
public static final LongKeyAnalyzer INSTANCE = new LongKeyAnalyzer();
/**
* A bit mask where the first bit is 1 and the others are zero
*/
private static final long MSB = 1 << Long.SIZE-1;
/**
* Returns a bit mask where the given bit is set
*/
private static long mask(int bit) {
return MSB >>> bit;
}
public int lengthInBits(Long key) {
return Long.SIZE;
}
public boolean isBitSet(Long key, int bitIndex) {
return (key & mask(bitIndex)) != 0;
}
public int bitIndex(Long key, Long otherKey) {
long keyValue = key.longValue();
if (keyValue == 0) {
return NULL_BIT_KEY;
}
long otherValue = otherKey.longValue();
if (keyValue != otherValue) {
long xorValue = keyValue ^ otherValue;
for (int i = 0; i < Long.SIZE; i++) {
if ((xorValue & mask(i)) != 0) {
return i;
}
}
}
return KeyAnalyzer.EQUAL_BIT_KEY;
}
public boolean isPrefix(Long key, Long prefix) {
return key.equals(prefix);
}
}