MQTT / MQTTPacket

Basic C library for MQTT packet serialization and deserialization

Dependents:   MQTT MQTT MQTT MQTT ... more

Fork of MQTTPacket by MQTT

This library is part of the EclipseTM Paho project; specifically the embedded client.

A basic MQTT library in C for packet serialization and deserialization

MQTTSubscribeServer.c@0:7734401cc1b4, 2014-02-04 (annotated)

Committer:
icraggs
Date:
Tue Feb 04 22:31:32 2014 +0000
Revision:
0:7734401cc1b4
Child:
14:c2052aee81de
First version of MQTT library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
icraggs 0:7734401cc1b4 1 /*******************************************************************************
icraggs 0:7734401cc1b4 2 * Copyright (c) 2014 IBM Corp.
icraggs 0:7734401cc1b4 3 *
icraggs 0:7734401cc1b4 4 * All rights reserved. This program and the accompanying materials
icraggs 0:7734401cc1b4 5 * are made available under the terms of the Eclipse Public License v1.0
icraggs 0:7734401cc1b4 6 * and Eclipse Distribution License v1.0 which accompany this distribution.
icraggs 0:7734401cc1b4 7 *
icraggs 0:7734401cc1b4 8 * The Eclipse Public License is available at
icraggs 0:7734401cc1b4 9 * http://www.eclipse.org/legal/epl-v10.html
icraggs 0:7734401cc1b4 10 * and the Eclipse Distribution License is available at
icraggs 0:7734401cc1b4 11 * http://www.eclipse.org/org/documents/edl-v10.php.
icraggs 0:7734401cc1b4 12 *
icraggs 0:7734401cc1b4 13 * Contributors:
icraggs 0:7734401cc1b4 14 * Ian Craggs - initial API and implementation and/or initial documentation
icraggs 0:7734401cc1b4 15 *******************************************************************************/
icraggs 0:7734401cc1b4 16
icraggs 0:7734401cc1b4 17 #include "MQTTPacket.h"
icraggs 0:7734401cc1b4 18 #include "StackTrace.h"
icraggs 0:7734401cc1b4 19
icraggs 0:7734401cc1b4 20 #include <string.h>
icraggs 0:7734401cc1b4 21
icraggs 0:7734401cc1b4 22
icraggs 0:7734401cc1b4 23 /**
icraggs 0:7734401cc1b4 24 * Deserializes the supplied (wire) buffer into subscribe data
icraggs 0:7734401cc1b4 25 * @param dup integer returned - the MQTT dup flag
icraggs 0:7734401cc1b4 26 * @param packetid integer returned - the MQTT packet identifier
icraggs 0:7734401cc1b4 27 * @param maxcount - the maximum number of members allowed in the topicFilters and requestedQoSs arrays
icraggs 0:7734401cc1b4 28 * @param count - number of members in the topicFilters and requestedQoSs arrays
icraggs 0:7734401cc1b4 29 * @param topicFilters - array of topic filter names
icraggs 0:7734401cc1b4 30 * @param requestedQoSs - array of requested QoS
icraggs 0:7734401cc1b4 31 * @param buf the raw buffer data, of the correct length determined by the remaining length field
icraggs 0:7734401cc1b4 32 * @param buflen the length in bytes of the data in the supplied buffer
icraggs 0:7734401cc1b4 33 * @return the length of the serialized data. <= 0 indicates error
icraggs 0:7734401cc1b4 34 */
icraggs 0:7734401cc1b4 35 int MQTTDeserialize_subscribe(int* dup, int* packetid, int maxcount, int* count, MQTTString topicFilters[], int requestedQoSs[],
icraggs 0:7734401cc1b4 36 char* buf, int buflen)
icraggs 0:7734401cc1b4 37 {
icraggs 0:7734401cc1b4 38 MQTTHeader header;
icraggs 0:7734401cc1b4 39 char* curdata = buf;
icraggs 0:7734401cc1b4 40 char* enddata = NULL;
icraggs 0:7734401cc1b4 41 int rc = -1;
icraggs 0:7734401cc1b4 42 int mylen = 0;
icraggs 0:7734401cc1b4 43
icraggs 0:7734401cc1b4 44 FUNC_ENTRY;
icraggs 0:7734401cc1b4 45 header.byte = readChar(&curdata);
icraggs 0:7734401cc1b4 46 *dup = header.bits.dup;
icraggs 0:7734401cc1b4 47
icraggs 0:7734401cc1b4 48 curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
icraggs 0:7734401cc1b4 49 enddata = curdata + mylen;
icraggs 0:7734401cc1b4 50
icraggs 0:7734401cc1b4 51 *packetid = readInt(&curdata);
icraggs 0:7734401cc1b4 52
icraggs 0:7734401cc1b4 53 *count = 0;
icraggs 0:7734401cc1b4 54 while (curdata < enddata)
icraggs 0:7734401cc1b4 55 {
icraggs 0:7734401cc1b4 56 if (!readMQTTLenString(&topicFilters[*count], &curdata, enddata))
icraggs 0:7734401cc1b4 57 goto exit;
icraggs 0:7734401cc1b4 58 if (curdata >= enddata) /* do we have enough data to read the req_qos version byte? */
icraggs 0:7734401cc1b4 59 goto exit;
icraggs 0:7734401cc1b4 60 requestedQoSs[*count] = readChar(&curdata);
icraggs 0:7734401cc1b4 61 (*count)++;
icraggs 0:7734401cc1b4 62 }
icraggs 0:7734401cc1b4 63
icraggs 0:7734401cc1b4 64 rc = 1;
icraggs 0:7734401cc1b4 65 exit:
icraggs 0:7734401cc1b4 66 FUNC_EXIT_RC(rc);
icraggs 0:7734401cc1b4 67 return rc;
icraggs 0:7734401cc1b4 68 }
icraggs 0:7734401cc1b4 69
icraggs 0:7734401cc1b4 70
icraggs 0:7734401cc1b4 71 /**
icraggs 0:7734401cc1b4 72 * Serializes the supplied suback data into the supplied buffer, ready for sending
icraggs 0:7734401cc1b4 73 * @param buf the buffer into which the packet will be serialized
icraggs 0:7734401cc1b4 74 * @param buflen the length in bytes of the supplied buffer
icraggs 0:7734401cc1b4 75 * @param packetid integer - the MQTT packet identifier
icraggs 0:7734401cc1b4 76 * @param count - number of members in the grantedQoSs array
icraggs 0:7734401cc1b4 77 * @param grantedQoSs - array of granted QoS
icraggs 0:7734401cc1b4 78 * @return the length of the serialized data. <= 0 indicates error
icraggs 0:7734401cc1b4 79 */
icraggs 0:7734401cc1b4 80 int MQTTSerialize_suback(char* buf, int buflen, int packetid, int count, int* grantedQoSs)
icraggs 0:7734401cc1b4 81 {
icraggs 0:7734401cc1b4 82 MQTTHeader header;
icraggs 0:7734401cc1b4 83 int rc = -1;
icraggs 0:7734401cc1b4 84 char *ptr = buf;
icraggs 0:7734401cc1b4 85 int i;
icraggs 0:7734401cc1b4 86
icraggs 0:7734401cc1b4 87 FUNC_ENTRY;
icraggs 0:7734401cc1b4 88 if (buflen < 2 + count)
icraggs 0:7734401cc1b4 89 {
icraggs 0:7734401cc1b4 90 rc = MQTTPACKET_BUFFER_TOO_SHORT;
icraggs 0:7734401cc1b4 91 goto exit;
icraggs 0:7734401cc1b4 92 }
icraggs 0:7734401cc1b4 93 header.byte = 0;
icraggs 0:7734401cc1b4 94 header.bits.type = SUBACK;
icraggs 0:7734401cc1b4 95 writeChar(&ptr, header.byte); /* write header */
icraggs 0:7734401cc1b4 96
icraggs 0:7734401cc1b4 97 ptr += MQTTPacket_encode(ptr, 2 + count); /* write remaining length */
icraggs 0:7734401cc1b4 98
icraggs 0:7734401cc1b4 99 writeInt(&ptr, packetid);
icraggs 0:7734401cc1b4 100
icraggs 0:7734401cc1b4 101 for (i = 0; i < count; ++i)
icraggs 0:7734401cc1b4 102 writeChar(&ptr, grantedQoSs[i]);
icraggs 0:7734401cc1b4 103
icraggs 0:7734401cc1b4 104 rc = ptr - buf;
icraggs 0:7734401cc1b4 105 exit:
icraggs 0:7734401cc1b4 106 FUNC_EXIT_RC(rc);
icraggs 0:7734401cc1b4 107 return rc;
icraggs 0:7734401cc1b4 108 }
icraggs 0:7734401cc1b4 109
icraggs 0:7734401cc1b4 110