001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.fusesource.hawtbuf.codec; 018 019 import java.io.DataInput; 020 import java.io.DataOutput; 021 import java.io.IOException; 022 023 /** 024 * Implementation of a variable length Codec for a signed Long 025 * 026 */ 027 public class VarSignedLongCodec extends VarLongCodec { 028 029 public static final VarSignedLongCodec INSTANCE = new VarSignedLongCodec(); 030 031 032 public void encode(Long value, DataOutput dataOut) throws IOException { 033 super.encode(encodeZigZag(value), dataOut); 034 } 035 036 public Long decode(DataInput dataIn) throws IOException { 037 return decodeZigZag(super.decode(dataIn)); 038 } 039 040 private static long decodeZigZag(long n) { 041 return (n >>> 1) ^ -(n & 1); 042 } 043 044 private static long encodeZigZag(long n) { 045 return (n << 1) ^ (n >> 63); 046 } 047 048 public int estimatedSize(Long value) { 049 return super.estimatedSize(encodeZigZag(value)); 050 } 051 }