1 /*******************************************************************************
2 * Copyright (c) 2014 IBM Corp.
3 *
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * and Eclipse Distribution License v1.0 which accompany this distribution.
7 *
8 * The Eclipse Public License is available at
9 * http://www.eclipse.org/legal/epl-v10.html
10 * and the Eclipse Distribution License is available at
11 * http://www.eclipse.org/org/documents/edl-v10.php.
12 *
13 * Contributors:
14 * Ian Craggs - initial API and implementation and/or initial documentation
15 *******************************************************************************/
16
17 #include "MQTTPacket.h"
18
19 #include <string.h>
20
21
22 /**
23 * Determines the length of the MQTT unsubscribe packet that would be produced
24 * using the supplied parameters
25 * @param count the number of topic filter strings in topicFilters
26 * @param topicFilters the array of topic filter strings to be used in the
27 * publish
28 * @return the length of buffer needed to contain the serialized version of the
29 * packet
30 */
MQTTSerialize_unsubscribeLength(int count,MQTTString topicFilters[])31 int MQTTSerialize_unsubscribeLength(int count, MQTTString topicFilters[])
32 {
33 int i;
34 int len = 2; /* packetid */
35
36 for (i = 0; i < count; ++i) {
37 len += 2 + MQTTstrlen(topicFilters[i]); /* length + topic*/
38 }
39 return len;
40 }
41
42 /**
43 * Serializes the supplied unsubscribe data into the supplied buffer, ready for
44 * sending
45 * @param buf the raw buffer data, of the correct length determined by the
46 * remaining length field
47 * @param buflen the length in bytes of the data in the supplied buffer
48 * @param dup integer - the MQTT dup flag
49 * @param packetid integer - the MQTT packet identifier
50 * @param count - number of members in the topicFilters array
51 * @param topicFilters - array of topic filter names
52 * @return the length of the serialized data. <= 0 indicates error
53 */
MQTTSerialize_unsubscribe(unsigned char * buf,int buflen,unsigned char dup,unsigned short packetid,int count,MQTTString topicFilters[])54 int MQTTSerialize_unsubscribe(unsigned char *buf, int buflen, unsigned char dup,
55 unsigned short packetid, int count,
56 MQTTString topicFilters[])
57 {
58 unsigned char *ptr = buf;
59 MQTTHeader header = { 0 };
60 int rem_len = 0;
61 int rc = -1;
62 int i = 0;
63
64 rem_len = MQTTSerialize_unsubscribeLength(count, topicFilters);
65 if (MQTTPacket_len(rem_len) > buflen) {
66 rc = MQTTPACKET_BUFFER_TOO_SHORT;
67 goto exit;
68 }
69
70 header.byte = 0;
71 MQTT_HEADER_SET_TYPE(header.byte, UNSUBSCRIBE);
72 MQTT_HEADER_SET_DUP(header.byte, dup);
73 MQTT_HEADER_SET_QOS(header.byte, 1);
74 writeChar(&ptr, header.byte); /* write header */
75
76 ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */
77 ;
78
79 writeInt(&ptr, packetid);
80
81 for (i = 0; i < count; ++i) {
82 writeMQTTString(&ptr, topicFilters[i]);
83 }
84
85 rc = ptr - buf;
86 exit:
87 return rc;
88 }
89
90 /**
91 * Deserializes the supplied (wire) buffer into unsuback data
92 * @param packetid returned integer - the MQTT packet identifier
93 * @param buf the raw buffer data, of the correct length determined by the
94 * remaining length field
95 * @param buflen the length in bytes of the data in the supplied buffer
96 * @return error code. 1 is success, 0 is failure
97 */
MQTTDeserialize_unsuback(unsigned short * packetid,unsigned char * buf,int buflen)98 int MQTTDeserialize_unsuback(unsigned short *packetid, unsigned char *buf,
99 int buflen)
100 {
101 unsigned char type = 0;
102 unsigned char dup = 0;
103 int rc = 0;
104
105 rc = MQTTDeserialize_ack(&type, &dup, packetid, buf, buflen);
106 if (type == UNSUBACK) {
107 rc = 1;
108 }
109 return rc;
110 }
111