| /* |
| * 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. |
| * |
| */ |
| |
| package org.apache.directory.server.ntp.io; |
| |
| |
| import java.nio.ByteBuffer; |
| |
| import org.apache.directory.server.ntp.messages.LeapIndicatorType; |
| import org.apache.directory.server.ntp.messages.ModeType; |
| import org.apache.directory.server.ntp.messages.NtpMessage; |
| import org.apache.directory.server.ntp.messages.NtpMessageModifier; |
| import org.apache.directory.server.ntp.messages.NtpTimeStamp; |
| import org.apache.directory.server.ntp.messages.ReferenceIdentifier; |
| import org.apache.directory.server.ntp.messages.StratumType; |
| |
| |
| /** |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| * @version $Rev$, $Date$ |
| */ |
| public class NtpMessageDecoder |
| { |
| /** |
| * Decodes the {@link ByteBuffer} into an {@link NtpMessage}. |
| * |
| * @param request |
| * @return The {@link NtpMessage}. |
| */ |
| public NtpMessage decode( ByteBuffer request ) |
| { |
| NtpMessageModifier modifier = new NtpMessageModifier(); |
| |
| byte header = request.get(); |
| modifier.setLeapIndicator( parseLeapIndicator( header ) ); |
| modifier.setVersionNumber( parseVersionNumber( header ) ); |
| modifier.setMode( parseMode( header ) ); |
| modifier.setStratum( parseStratum( request ) ); |
| modifier.setPollInterval( parsePollInterval( request ) ); |
| modifier.setPrecision( parsePrecision( request ) ); |
| modifier.setRootDelay( parseRootDelay( request ) ); |
| modifier.setRootDispersion( parseRootDispersion( request ) ); |
| modifier.setReferenceIdentifier( parseReferenceIdentifier( request ) ); |
| modifier.setReferenceTimestamp( new NtpTimeStamp( request ) ); |
| modifier.setOriginateTimestamp( new NtpTimeStamp( request ) ); |
| |
| byte[] unneededBytes = new byte[8]; |
| request.get( unneededBytes ); |
| |
| modifier.setReceiveTimestamp( new NtpTimeStamp() ); |
| modifier.setTransmitTimestamp( new NtpTimeStamp( request ) ); |
| |
| return modifier.getNtpMessage(); |
| } |
| |
| |
| private LeapIndicatorType parseLeapIndicator( byte header ) |
| { |
| return LeapIndicatorType.getTypeByOrdinal( ( header & 0xc0 ) >>> 6 ); |
| } |
| |
| |
| private int parseVersionNumber( byte header ) |
| { |
| return ( header & 0x38 ) >>> 3; |
| } |
| |
| |
| private ModeType parseMode( byte header ) |
| { |
| return ModeType.getTypeByOrdinal( header & 0x07 ); |
| } |
| |
| |
| private StratumType parseStratum( ByteBuffer request ) |
| { |
| return StratumType.getTypeByOrdinal( request.get() ); |
| } |
| |
| |
| private byte parsePollInterval( ByteBuffer bytes ) |
| { |
| return ( byte ) Math.round( Math.pow( 2, bytes.get() ) ); |
| } |
| |
| |
| private byte parsePrecision( ByteBuffer bytes ) |
| { |
| return ( byte ) ( 1000 * Math.pow( 2, bytes.get() ) ); |
| } |
| |
| |
| private ReferenceIdentifier parseReferenceIdentifier( ByteBuffer request ) |
| { |
| byte[] nextFourBytes = new byte[4]; |
| request.get( nextFourBytes ); |
| return ReferenceIdentifier.getTypeByName( new String( nextFourBytes ) ); |
| } |
| |
| |
| private int parseRootDelay( ByteBuffer bytes ) |
| { |
| int temp = 256 * ( 256 * ( 256 * bytes.get() + bytes.get() ) + bytes.get() ) + bytes.get(); |
| return 1000 * ( temp / 0x10000 ); |
| } |
| |
| |
| private int parseRootDispersion( ByteBuffer bytes ) |
| { |
| int temp = 256 * ( 256 * ( 256 * bytes.get() + bytes.get() ) + bytes.get() ) + bytes.get(); |
| return 1000 * ( temp / 0x10000 ); |
| } |
| } |