/*******************************************************************************
* Copyright 2010 Cees De Groot, Alex Boisvert, Jan Kotek
*
* 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.apache.jdbm;
import java.io.Serializable;
import java.util.Comparator;
/**
* Comparator for byte arrays.
*
* @author Alex Boisvert
*/
public final class ByteArrayComparator
implements Comparator<byte[]>, Serializable {
/**
* Version id for serialization.
*/
final static long serialVersionUID = 1L;
/**
* Compare two objects.
*
* @param obj1 First object
* @param obj2 Second object
* @return a positive integer if obj1 > obj2, 0 if obj1 == obj2,
* and a negative integer if obj1 < obj2
*/
public int compare(byte[] obj1, byte[] obj2) {
if (obj1 == null) {
throw new IllegalArgumentException("Argument 'obj1' is null");
}
if (obj2 == null) {
throw new IllegalArgumentException("Argument 'obj2' is null");
}
return compareByteArray(obj1, obj2);
}
/**
* Compare two byte arrays.
*/
public static int compareByteArray(byte[] thisKey, byte[] otherKey) {
int len = Math.min(thisKey.length, otherKey.length);
// compare the byte arrays
for (int i = 0; i < len; i++) {
if (thisKey[i] >= 0) {
if (otherKey[i] >= 0) {
// both positive
if (thisKey[i] < otherKey[i]) {
return -1;
} else if (thisKey[i] > otherKey[i]) {
return 1;
}
} else {
// otherKey is negative => greater (because MSB is 1)
return -1;
}
} else {
if (otherKey[i] >= 0) {
// thisKey is negative => greater (because MSB is 1)
return 1;
} else {
// both negative
if (thisKey[i] < otherKey[i]) {
return -1;
} else if (thisKey[i] > otherKey[i]) {
return 1;
}
}
}
}
if (thisKey.length == otherKey.length) {
return 0;
}
if (thisKey.length < otherKey.length) {
return -1;
}
return 1;
}
}