mirror of
https://github.com/eclipse/paho.mqtt-sn.embedded-c.git
synced 2025-12-16 08:56:51 +01:00
291 lines
8.9 KiB
C
291 lines
8.9 KiB
C
/*******************************************************************************
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* Copyright (c) 2014 IBM Corp.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* and Eclipse Distribution License v1.0 which accompany this distribution.
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*
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* The Eclipse Public License is available at
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* http://www.eclipse.org/legal/epl-v10.html
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* and the Eclipse Distribution License is available at
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* http://www.eclipse.org/org/documents/edl-v10.php.
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*
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* Contributors:
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* Ian Craggs - initial API and implementation and/or initial documentation
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*******************************************************************************/
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#include "MQTTSNPacket.h"
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#include "StackTrace.h"
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#include <string.h>
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/**
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* Determines the length of the MQTT publish packet that would be produced using the supplied parameters
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* @param qos the MQTT QoS of the publish (packetid is omitted for QoS 0)
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* @param topicName the topic name to be used in the publish
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* @param payloadlen the length of the payload to be sent
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* @return the length of buffer needed to contain the serialized version of the packet
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*/
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int MQTTSNSerialize_publishLength(int payloadlen, MQTTSN_topicid topic, int qos)
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{
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int len = 6;
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if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
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len += topic.data.long_.len;
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return payloadlen + len;
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}
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/**
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* Serializes the supplied publish data into the supplied buffer, ready for sending
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param dup integer - the MQTT dup flag
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* @param qos integer - the MQTT QoS value
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* @param retained integer - the MQTT retained flag
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* @param packetid integer - the MQTT packet identifier
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* @param topic MQTTSN_topicid - the MQTT topic in the publish
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* @param payload byte buffer - the MQTT publish payload
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* @param payloadlen integer - the length of the MQTT payload
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* @return the length of the serialized data. <= 0 indicates error
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*/
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int MQTTSNSerialize_publish(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned char retained, unsigned short packetid,
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MQTTSN_topicid topic, unsigned char* payload, int payloadlen)
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{
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unsigned char *ptr = buf;
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MQTTSNFlags flags;
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int len = 0;
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int rc = 0;
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FUNC_ENTRY;
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if ((len = MQTTSNPacket_len(MQTTSNSerialize_publishLength(payloadlen, topic, qos))) > buflen)
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{
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rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
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goto exit;
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}
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ptr += MQTTSNPacket_encode(ptr, len); /* write length */
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writeChar(&ptr, MQTTSN_PUBLISH); /* write message type */
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flags.all = 0;
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flags.bits.dup = dup;
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flags.bits.QoS = qos;
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flags.bits.retain = retained;
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flags.bits.topicIdType = topic.type;
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writeChar(&ptr, flags.all);
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if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
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{
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/* special arrangement for long topic names in QoS -1 publishes. The length of the topic is in the topicid field */
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writeInt(&ptr, topic.data.long_.len); /* topic length */
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}
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else if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL || topic.type == MQTTSN_TOPIC_TYPE_PREDEFINED)
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writeInt(&ptr, topic.data.id);
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else
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{
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writeChar(&ptr, topic.data.short_name[0]);
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writeChar(&ptr, topic.data.short_name[1]);
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}
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writeInt(&ptr, packetid);
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if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
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{
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memcpy(ptr, topic.data.long_.name, topic.data.long_.len);
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ptr += topic.data.long_.len;
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}
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memcpy(ptr, payload, payloadlen);
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ptr += payloadlen;
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rc = ptr - buf;
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exit:
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FUNC_EXIT_RC(rc);
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return rc;
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}
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int MQTTSNSerialize_puback(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
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unsigned char returncode)
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{
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unsigned char *ptr = buf;
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int len = 0;
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int rc = 0;
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FUNC_ENTRY;
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if ((len = MQTTSNPacket_len(6)) > buflen)
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{
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rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
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goto exit;
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}
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ptr += MQTTSNPacket_encode(ptr, len); /* write length */
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writeChar(&ptr, MQTTSN_PUBACK); /* write message type */
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writeInt(&ptr, topicid);
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writeInt(&ptr, packetid);
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writeChar(&ptr, returncode);
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rc = ptr - buf;
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exit:
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FUNC_EXIT_RC(rc);
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return rc;
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}
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/**
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* Serializes the ack packet into the supplied buffer.
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param type the MQTT-SN packet type
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* @param packetid the MQTT-SN packet identifier
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* @return serialized length, or error if 0
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*/
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int MQTTSNSerialize_ack(unsigned char* buf, int buflen, unsigned short packet_type, unsigned short packetid)
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{
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int rc = 0;
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unsigned char *ptr = buf;
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int len = 4; /* ack packet length */
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FUNC_ENTRY;
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if (len > buflen)
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{
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rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
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goto exit;
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}
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ptr += MQTTSNPacket_encode(ptr, len); /* write length */
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writeChar(&ptr, packet_type); /* write packet type */
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writeInt(&ptr, packetid);
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rc = ptr - buf;
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exit:
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FUNC_EXIT_RC(rc);
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return rc;
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}
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/**
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* Serializes a puback packet into the supplied buffer.
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param packetid integer - the MQTT packet identifier
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* @return serialized length, or error if 0
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*/
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int MQTTSNSerialize_pubrec(unsigned char* buf, int buflen, unsigned short packetid)
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{
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return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREC, packetid);
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}
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/**
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* Serializes a pubrel packet into the supplied buffer.
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param dup integer - the MQTT dup flag
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* @param packetid integer - the MQTT packet identifier
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* @return serialized length, or error if 0
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*/
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int MQTTSNSerialize_pubrel(unsigned char* buf, int buflen, unsigned short packetid)
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{
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return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREL, packetid);
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}
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/**
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* Serializes a pubrel packet into the supplied buffer.
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param packetid integer - the MQTT packet identifier
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* @return serialized length, or error if 0
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*/
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int MQTTSNSerialize_pubcomp(unsigned char* buf, int buflen, unsigned short packetid)
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{
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return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBCOMP, packetid);
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}
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/**
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* Determines the length of the MQTT register packet that would be produced using the supplied parameters
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* @param topicnamelen the length of the topic name to be used in the register
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* @return the length of buffer needed to contain the serialized version of the packet
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*/
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int MQTTSNSerialize_registerLength(int topicnamelen)
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{
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return topicnamelen + 5;
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}
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/**
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* Serializes the supplied register data into the supplied buffer, ready for sending
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param topicid if sent by a gateway, contains the id for the topicname, otherwise 0
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* @param packetid integer - the MQTT packet identifier
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* @param topicname null-terminated topic name string
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* @return the length of the serialized data. <= 0 indicates error
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*/
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int MQTTSNSerialize_register(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
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MQTTSNString* topicname)
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{
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unsigned char *ptr = buf;
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int len = 0;
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int rc = 0;
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int topicnamelen = 0;
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FUNC_ENTRY;
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topicnamelen = (topicname->cstring) ? strlen(topicname->cstring) : topicname->lenstring.len;
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if ((len = MQTTSNPacket_len(MQTTSNSerialize_registerLength(topicnamelen))) > buflen)
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{
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rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
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goto exit;
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}
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ptr += MQTTSNPacket_encode(ptr, len); /* write length */
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writeChar(&ptr, MQTTSN_REGISTER); /* write message type */
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writeInt(&ptr, topicid);
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writeInt(&ptr, packetid);
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memcpy(ptr, (topicname->cstring) ? topicname->cstring : topicname->lenstring.data, topicnamelen);
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ptr += topicnamelen;
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rc = ptr - buf;
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exit:
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FUNC_EXIT_RC(rc);
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return rc;
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}
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/**
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* Serializes the supplied register data into the supplied buffer, ready for sending
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* @param buf the buffer into which the packet will be serialized
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* @param buflen the length in bytes of the supplied buffer
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* @param topicid if sent by a gateway, contains the id for the topicname, otherwise 0
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* @param packetid integer - the MQTT packet identifier
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* @param return_code integer return code
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* @return the length of the serialized data. <= 0 indicates error
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*/
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int MQTTSNSerialize_regack(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
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unsigned char return_code)
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{
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unsigned char *ptr = buf;
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int len = 0;
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int rc = 0;
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FUNC_ENTRY;
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if ((len = MQTTSNPacket_len(6)) > buflen)
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{
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rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
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goto exit;
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}
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ptr += MQTTSNPacket_encode(ptr, len); /* write length */
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writeChar(&ptr, MQTTSN_REGACK); /* write message type */
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writeInt(&ptr, topicid);
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writeInt(&ptr, packetid);
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writeChar(&ptr, return_code);
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rc = ptr - buf;
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exit:
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FUNC_EXIT_RC(rc);
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return rc;
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}
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