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;
+}
+
+
+
+