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Diff: MQTTSNSubscribeClient.c
- Revision:
- 0:c524a894b5e8
- Child:
- 1:7fa362fa563f
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MQTTSNSubscribeClient.c Thu Feb 26 15:59:36 2015 +0000 @@ -0,0 +1,141 @@ +/******************************************************************************* + * 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 "MQTTSNPacket.h" +#include "StackTrace.h" + +#include <string.h> + +/** + * Determines the length of the MQTTSN subscribe packet that would be produced using the supplied parameters, + * excluding length + * @param topicName the topic name to be used in the publish + * @return the length of buffer needed to contain the serialized version of the packet + */ +int MQTTSNSerialize_subscribeLength(MQTTSN_topicid* topicFilter) +{ + int len = 4; + + if (topicFilter->type == MQTTSN_TOPIC_TYPE_NORMAL) + len += topicFilter->data.long_.len; + else if (topicFilter->type == MQTTSN_TOPIC_TYPE_SHORT || topicFilter->type == MQTTSN_TOPIC_TYPE_PREDEFINED) + len += 2; + + return len; +} + + +/** + * Serializes the supplied subscribe 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 dup integer - the MQTT-SN dup flag + * @param qos integer - the MQTT-SN QoS value + * @param packetid integer - the MQTT-SN packet identifier + * @param topic MQTTSN_topicid - the MQTT-SN topic in the subscribe + * @return the length of the serialized data. <= 0 indicates error + */ +int MQTTSNSerialize_subscribe(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned short packetid, + MQTTSN_topicid* topicFilter) +{ + unsigned char *ptr = buf; + MQTTSNFlags flags; + int len = 0; + int rc = 0; + + FUNC_ENTRY; + if ((len = MQTTSNPacket_len(MQTTSNSerialize_subscribeLength(topicFilter))) > buflen) + { + rc = MQTTSNPACKET_BUFFER_TOO_SHORT; + goto exit; + } + ptr += MQTTSNPacket_encode(ptr, len); /* write length */ + writeChar(&ptr, MQTTSN_SUBSCRIBE); /* write message type */ + + flags.all = 0; + flags.bits.dup = dup; + flags.bits.QoS = qos; + flags.bits.topicIdType = topicFilter->type; + writeChar(&ptr, flags.all); + + writeInt(&ptr, packetid); + + /* now the topic id or name */ + if (topicFilter->type == MQTTSN_TOPIC_TYPE_NORMAL) /* means long topic name */ + { + memcpy(ptr, topicFilter->data.long_.name, topicFilter->data.long_.len); + ptr += topicFilter->data.long_.len; + } + else if (topicFilter->type == MQTTSN_TOPIC_TYPE_PREDEFINED) + writeInt(&ptr, topicFilter->data.id); + else if (topicFilter->type == MQTTSN_TOPIC_TYPE_SHORT) + { + writeChar(&ptr, topicFilter->data.short_name[0]); + writeChar(&ptr, topicFilter->data.short_name[1]); + } + + rc = ptr - buf; +exit: + FUNC_EXIT_RC(rc); + return rc; + +} + + +/** + * Deserializes the supplied (wire) buffer into suback data + * @param qos the returned qos + * @param topicid returned if "accepted" the value which will be used by the gateway in subsequent PUBLISH packets + * @param packetid returned - the same value as the one contained in the corresponding SUBSCRIBE + * @param returncode returned - "accepted" or rejection reason + * @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 error code. 1 is success + */ +int MQTTSNDeserialize_suback(int* qos, unsigned short* topicid, unsigned short* packetid, + unsigned char* returncode, unsigned char* buf, int buflen) +{ + MQTTSNFlags flags; + unsigned char* curdata = buf; + unsigned char* enddata = NULL; + int rc = 0; + int mylen = 0; + + FUNC_ENTRY; + curdata += (rc = MQTTSNPacket_decode(curdata, buflen, &mylen)); /* read length */ + enddata = buf + mylen; + if (enddata - curdata > buflen) + goto exit; + + if (readChar(&curdata) != MQTTSN_SUBACK) + goto exit; + + flags.all = readChar(&curdata); + *qos = flags.bits.QoS; + + *topicid = readInt(&curdata); + *packetid = readInt(&curdata); + *returncode = readChar(&curdata); + + rc = 1; +exit: + FUNC_EXIT_RC(rc); + return rc; +} + + + +