content: /**
   * 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.activemq.transport.mqtt;
  
  import java.io.DataInput;
  import java.io.DataInputStream;
  import java.io.DataOutput;
  import java.io.DataOutputStream;
  import java.io.IOException;
  
  import org.apache.activemq.util.ByteArrayInputStream;
  import org.apache.activemq.util.ByteArrayOutputStream;
  import org.apache.activemq.util.ByteSequence;
  import org.apache.activemq.wireformat.WireFormat;
  import org.fusesource.hawtbuf.Buffer;
  import org.fusesource.mqtt.codec.MQTTFrame;
  
  /**
   * Implements marshalling and unmarsalling the <a
   * href="http://mqtt.org/">MQTT</a> protocol.
   */
  public class MQTTWireFormat implements WireFormat {
  
      static final int MAX_MESSAGE_LENGTH = 1024 * 1024 * 256;
      static final long DEFAULT_CONNECTION_TIMEOUT = 30000L;
  
      private int version = 1;
  
      private int maxFrameSize = MAX_MESSAGE_LENGTH;
      private long connectAttemptTimeout = MQTTWireFormat.DEFAULT_CONNECTION_TIMEOUT;
  
      @Override
      public ByteSequence marshal(Object command) throws IOException {
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          DataOutputStream dos = new DataOutputStream(baos);
          marshal(command, dos);
          dos.close();
          return baos.toByteSequence();
      }
  
      @Override
      public Object unmarshal(ByteSequence packet) throws IOException {
          ByteArrayInputStream stream = new ByteArrayInputStream(packet);
          DataInputStream dis = new DataInputStream(stream);
          return unmarshal(dis);
      }
  
      @Override
      public void marshal(Object command, DataOutput dataOut) throws IOException {
          MQTTFrame frame = (MQTTFrame) command;
          dataOut.write(frame.header());
  
          int remaining = 0;
          for (Buffer buffer : frame.buffers) {
              remaining += buffer.length;
          }
          do {
              byte digit = (byte) (remaining & 0x7F);
              remaining >>>= 7;
              if (remaining > 0) {
                  digit |= 0x80;
              }
              dataOut.write(digit);
          } while (remaining > 0);
          for (Buffer buffer : frame.buffers) {
              dataOut.write(buffer.data, buffer.offset, buffer.length);
          }
      }
  
      @Override
      public Object unmarshal(DataInput dataIn) throws IOException {
          byte header = dataIn.readByte();
  
          byte digit;
          int multiplier = 1;
          int length = 0;
          do {
              digit = dataIn.readByte();
              length += (digit & 0x7F) * multiplier;
              multiplier <<= 7;
          }
          while ((digit & 0x80) != 0);
  
          if (length >= 0) {
              if (length > getMaxFrameSize()) {
                  throw new IOException("The maximum message length was exceeded");
              }
  
              if (length > 0) {
                  byte[] data = new byte[length];
                  dataIn.readFully(data);
                  Buffer body = new Buffer(data);
                  return new MQTTFrame(body).header(header);
              } else {
                  return new MQTTFrame().header(header);
              }
          }
          return null;
      }
  
      /**
       * @param version the version of the wire format
       */
      @Override
      public void setVersion(int version) {
          this.version = version;
      }
  
      /**
       * @return the version of the wire format
       */
      @Override
      public int getVersion() {
          return this.version;
      }
  
      /**
       * @return the maximum number of bytes a single MQTT message frame is allowed to be.
       */
      public int getMaxFrameSize() {
          return maxFrameSize;
      }
  
      /**
       * Sets the maximum frame size for an incoming MQTT frame.  The protocl limit is
       * 256 megabytes and this value cannot be set higher.
       *
       * @param maxFrameSize
       *        the maximum allowed frame size for a single MQTT frame.
       */
      public void setMaxFrameSize(int maxFrameSize) {
          this.maxFrameSize = Math.min(MAX_MESSAGE_LENGTH, maxFrameSize);
      }
  
      /**
       * @return the timeout value used to fail a connection if no CONNECT frame read.
       */
      public long getConnectAttemptTimeout() {
          return connectAttemptTimeout;
      }
  
      /**
       * Sets the timeout value used to fail a connection if no CONNECT frame is read
       * in the given interval.
       *
       * @param connectTimeout
       *        the connection frame received timeout value.
       */
      public void setConnectAttemptTimeout(long connectTimeout) {
          this.connectAttemptTimeout = connectTimeout;
      }
  }
  