/*
* Copyright 2010 NCHOVY
*
* 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.krakenapps.pcap.util;
/**
* @author mindori
*/
public class Checksum {
private Checksum() {
}
public static int sum(short[] words) {
int[] complements = new int[words.length];
for (int i = 0; i < complements.length; i++)
complements[i] = ~words[i] & 0xffff;
int sum = 0;
for (int i = 0; i < complements.length; i++)
sum = UnsignedCalc.unsignedAdd(sum, complements[i]);
int msb = (sum >> 16) & 0xffff;
return (sum & 0xffff) + msb;
}
}