MQTTDeserializePublish.c

00001 /*******************************************************************************
00002  * Copyright (c) 2014 IBM Corp.
00003  *
00004  * All rights reserved. This program and the accompanying materials
00005  * are made available under the terms of the Eclipse Public License v1.0
00006  * and Eclipse Distribution License v1.0 which accompany this distribution.
00007  *
00008  * The Eclipse Public License is available at
00009  *    http://www.eclipse.org/legal/epl-v10.html
00010  * and the Eclipse Distribution License is available at
00011  *   http://www.eclipse.org/org/documents/edl-v10.php.
00012  *
00013  * Contributors:
00014  *    Ian Craggs - initial API and implementation and/or initial documentation
00015  *******************************************************************************/
00016 
00017 #include "StackTrace.h"
00018 #include "MQTTPacket.h"
00019 #include <string.h>
00020 
00021 #define min(a, b) ((a < b) ? 1 : 0)
00022 
00023 /**
00024   * Deserializes the supplied (wire) buffer into publish data
00025   * @param dup returned integer - the MQTT dup flag
00026   * @param qos returned integer - the MQTT QoS value
00027   * @param retained returned integer - the MQTT retained flag
00028   * @param packetid returned integer - the MQTT packet identifier
00029   * @param topicName returned MQTTString - the MQTT topic in the publish
00030   * @param payload returned byte buffer - the MQTT publish payload
00031   * @param payloadlen returned integer - the length of the MQTT payload
00032   * @param buf the raw buffer data, of the correct length determined by the remaining length field
00033   * @param buflen the length in bytes of the data in the supplied buffer
00034   * @return error code.  1 is success
00035   */
00036 int MQTTDeserialize_publish(unsigned char* dup, int* qos, unsigned char* retained, unsigned short* packetid, MQTTString* topicName,
00037         unsigned char** payload, int* payloadlen, unsigned char* buf, int buflen)
00038 {
00039     MQTTHeader header = {0};
00040     unsigned char* curdata = buf;
00041     unsigned char* enddata = NULL;
00042     int rc = 0;
00043     int mylen = 0;
00044 
00045     FUNC_ENTRY;
00046     header.byte = readChar(&curdata);
00047     if (header.bits.type != PUBLISH)
00048         goto exit;
00049     *dup = header.bits.dup;
00050     *qos = header.bits.qos;
00051     *retained = header.bits.retain;
00052 
00053     curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
00054     enddata = curdata + mylen;
00055 
00056     if (!readMQTTLenString(topicName, &curdata, enddata) ||
00057         enddata - curdata < 0) {/* do we have enough data to read the protocol version byte? */
00058         rc = 0;
00059         goto exit;
00060     }
00061 
00062     if (*qos > 0)
00063         *packetid = readInt(&curdata);
00064 
00065     *payloadlen = enddata - curdata;
00066     *payload = curdata;
00067     rc = 1;
00068 exit:
00069     FUNC_EXIT_RC(rc);
00070     return rc;
00071 }
00072 
00073 
00074 
00075 /**
00076   * Deserializes the supplied (wire) buffer into an ack
00077   * @param packettype returned integer - the MQTT packet type
00078   * @param dup returned integer - the MQTT dup flag
00079   * @param packetid returned integer - the MQTT packet identifier
00080   * @param buf the raw buffer data, of the correct length determined by the remaining length field
00081   * @param buflen the length in bytes of the data in the supplied buffer
00082   * @return error code.  1 is success, 0 is failure
00083   */
00084 int MQTTDeserialize_ack(unsigned char* packettype, unsigned char* dup, unsigned short* packetid, unsigned char* buf, int buflen)
00085 {
00086     MQTTHeader header = {0};
00087     unsigned char* curdata = buf;
00088     unsigned char* enddata = NULL;
00089     int rc = 0;
00090     int mylen;
00091 
00092     FUNC_ENTRY;
00093     header.byte = readChar(&curdata);
00094     *dup = header.bits.dup;
00095     *packettype = header.bits.type;
00096 
00097     curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
00098     enddata = curdata + mylen;
00099 
00100     if (enddata - curdata < 2)
00101         goto exit;
00102     *packetid = readInt(&curdata);
00103 
00104     rc = 1;
00105 exit:
00106     FUNC_EXIT_RC(rc);
00107     return rc;
00108 }
00109