text: /*******************************************************************************
   * Copyright (c) 2014 IBM Corp.
   *
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * and Eclipse Distribution License v1.0 which accompany this distribution.
   *
   * The Eclipse Public License is available at
   *    http://www.eclipse.org/legal/epl-v10.html
   * and the Eclipse Distribution License is available at
   *   http://www.eclipse.org/org/documents/edl-v10.php.
   *
   * Contributors:
   *    Ian Craggs - initial API and implementation and/or initial documentation
   *******************************************************************************/
  
  #include "MQTTPacket.h"
  #include "StackTrace.h"
  
  #include <string.h>
  
  
  /**
    * Deserializes the supplied (wire) buffer into unsubscribe data
    * @param dup integer returned - the MQTT dup flag
    * @param packetid integer returned - the MQTT packet identifier
    * @param maxcount - the maximum number of members allowed in the topicFilters and requestedQoSs arrays
    * @param count - number of members in the topicFilters and requestedQoSs arrays
    * @param topicFilters - array of topic filter names
    * @param buf the raw buffer data, of the correct length determined by the remaining length field
    * @param buflen the length in bytes of the data in the supplied buffer
    * @return the length of the serialized data.  <= 0 indicates error
    */
  int MQTTDeserialize_unsubscribe(unsigned char* dup, unsigned short* packetid, int maxcount, int* count, MQTTString topicFilters[],
  		unsigned char* buf, int len)
  {
  	MQTTHeader header = {0};
  	unsigned char* curdata = buf;
  	unsigned char* enddata = NULL;
  	int rc = 0;
  	int mylen = 0;
  	len = len;
  	maxcount = maxcount;
  
  	FUNC_ENTRY;
  	header.byte = readChar(&curdata);
  	if (header.bits.type != UNSUBSCRIBE)
  		goto exit;
  	*dup = header.bits.dup;
  
  	curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
  	enddata = curdata + mylen;
  
  	*packetid = readInt(&curdata);
  
  	*count = 0;
  	while (curdata < enddata)
  	{
  		if (!readMQTTLenString(&topicFilters[*count], &curdata, enddata))
  			goto exit;
  		(*count)++;
  	}
  
  	rc = 1;
  exit:
  	FUNC_EXIT_RC(rc);
  	return rc;
  }
  
  
  /**
    * Serializes the supplied unsuback data into the supplied buffer, ready for sending
    * @param buf the buffer into which the packet will be serialized
    * @param buflen the length in bytes of the supplied buffer
    * @param packetid integer - the MQTT packet identifier
    * @return the length of the serialized data.  <= 0 indicates error
    */
  int MQTTSerialize_unsuback(unsigned char* buf, int buflen, unsigned short packetid)
  {
  	MQTTHeader header = {0};
  	int rc = 0;
  	unsigned char *ptr = buf;
  
  	FUNC_ENTRY;
  	if (buflen < 2)
  	{
  		rc = MQTTPACKET_BUFFER_TOO_SHORT;
  		goto exit;
  	}
  	header.byte = 0;
  	header.bits.type = UNSUBACK;
  	writeChar(&ptr, header.byte); /* write header */
  
  	ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */
  
  	writeInt(&ptr, packetid);
  
  	rc = ptr - buf;
  exit:
  	FUNC_EXIT_RC(rc);
  	return rc;
  }
  
  
  