Diff: MQTTSNSerializePublish.c

Revision:

0:c524a894b5e8

Child:

1:7fa362fa563f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MQTTSNSerializePublish.c	Thu Feb 26 15:59:36 2015 +0000
@@ -0,0 +1,291 @@
+/*******************************************************************************
+ * 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 MQTT publish packet that would be produced using the supplied parameters
+  * @param qos the MQTT QoS of the publish (packetid is omitted for QoS 0)
+  * @param topicName the topic name to be used in the publish  
+  * @param payloadlen the length of the payload to be sent
+  * @return the length of buffer needed to contain the serialized version of the packet
+  */
+int MQTTSNSerialize_publishLength(int payloadlen, MQTTSN_topicid topic, int qos)
+{
+	int len = 6;
+
+	if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
+		len += topic.data.long_.len;
+
+	return payloadlen + len;
+}
+
+
+/**
+  * Serializes the supplied publish 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 dup flag
+  * @param qos integer - the MQTT QoS value
+  * @param retained integer - the MQTT retained flag
+  * @param packetid integer - the MQTT packet identifier
+  * @param topic MQTTSN_topicid - the MQTT topic in the publish
+  * @param payload byte buffer - the MQTT publish payload
+  * @param payloadlen integer - the length of the MQTT payload
+  * @return the length of the serialized data.  <= 0 indicates error
+  */
+int MQTTSNSerialize_publish(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned char retained, unsigned short packetid,
+		MQTTSN_topicid topic, unsigned char* payload, int payloadlen)
+{
+	unsigned char *ptr = buf;
+	MQTTSNFlags flags;
+	int len = 0;
+	int rc = 0;
+
+	FUNC_ENTRY;
+	if ((len = MQTTSNPacket_len(MQTTSNSerialize_publishLength(payloadlen, topic, qos))) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len); /* write length */
+	writeChar(&ptr, MQTTSN_PUBLISH);      /* write message type */
+
+	flags.all = 0;
+	flags.bits.dup = dup;
+	flags.bits.QoS = qos;
+	flags.bits.retain = retained;
+	flags.bits.topicIdType = topic.type;
+	writeChar(&ptr, flags.all);
+
+	if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
+	{
+		/* special arrangement for long topic names in QoS -1 publishes.  The length of the topic is in the topicid field */
+		writeInt(&ptr, topic.data.long_.len); /* topic length */
+	}
+	else if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL || topic.type == MQTTSN_TOPIC_TYPE_PREDEFINED)
+		writeInt(&ptr, topic.data.id);
+	else
+	{
+		writeChar(&ptr, topic.data.short_name[0]);
+		writeChar(&ptr, topic.data.short_name[1]);
+	}
+	writeInt(&ptr, packetid);
+	if (topic.type == MQTTSN_TOPIC_TYPE_NORMAL && qos == 3)
+	{
+		memcpy(ptr, topic.data.long_.name, topic.data.long_.len);
+		ptr += topic.data.long_.len;
+	}
+	memcpy(ptr, payload, payloadlen);
+	ptr += payloadlen;
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+int MQTTSNSerialize_puback(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
+		unsigned char returncode)
+{
+	unsigned char *ptr = buf;
+	int len = 0;
+	int rc = 0;
+
+	FUNC_ENTRY;
+	if ((len = MQTTSNPacket_len(6)) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len); /* write length */
+	writeChar(&ptr, MQTTSN_PUBACK);      /* write message type */
+
+	writeInt(&ptr, topicid);
+	writeInt(&ptr, packetid);
+	writeChar(&ptr, returncode);
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+
+}
+
+
+
+/**
+  * Serializes the ack packet into the supplied buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param buflen the length in bytes of the supplied buffer
+  * @param type the MQTT-SN packet type
+  * @param packetid the MQTT-SN packet identifier
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_ack(unsigned char* buf, int buflen, unsigned short packet_type, unsigned short packetid)
+{
+	int rc = 0;
+	unsigned char *ptr = buf;
+	int len = 4; /* ack packet length */
+
+	FUNC_ENTRY;
+	if (len > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len); /* write length */
+	writeChar(&ptr, packet_type);      /* write packet type */
+
+	writeInt(&ptr, packetid);
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+/**
+  * Serializes a puback packet into the supplied buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param buflen the length in bytes of the supplied buffer
+  * @param packetid integer - the MQTT packet identifier
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_pubrec(unsigned char* buf, int buflen, unsigned short packetid)
+{
+	return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREC, packetid);
+}
+
+
+/**
+  * Serializes a pubrel packet into the supplied buffer.
+  * @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 dup flag
+  * @param packetid integer - the MQTT packet identifier
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_pubrel(unsigned char* buf, int buflen, unsigned short packetid)
+{
+	return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBREL, packetid);
+}
+
+
+/**
+  * Serializes a pubrel packet into the supplied buffer.
+  * @param buf the buffer into which the packet will be serialized
+  * @param buflen the length in bytes of the supplied buffer
+  * @param packetid integer - the MQTT packet identifier
+  * @return serialized length, or error if 0
+  */
+int MQTTSNSerialize_pubcomp(unsigned char* buf, int buflen, unsigned short packetid)
+{
+	return MQTTSNSerialize_ack(buf, buflen, MQTTSN_PUBCOMP, packetid);
+}
+
+
+/**
+  * Determines the length of the MQTT register packet that would be produced using the supplied parameters
+  * @param topicnamelen the length of the topic name to be used in the register
+  * @return the length of buffer needed to contain the serialized version of the packet
+  */
+int MQTTSNSerialize_registerLength(int topicnamelen)
+{
+	return topicnamelen + 5;
+}
+
+/**
+  * Serializes the supplied register 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 topicid if sent by a gateway, contains the id for the topicname, otherwise 0
+  * @param packetid integer - the MQTT packet identifier
+  * @param topicname null-terminated topic name string
+  * @return the length of the serialized data.  <= 0 indicates error
+  */
+int MQTTSNSerialize_register(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
+		MQTTSNString* topicname)
+{
+	unsigned char *ptr = buf;
+	int len = 0;
+	int rc = 0;
+	int topicnamelen = 0;
+
+	FUNC_ENTRY;
+	topicnamelen = (topicname->cstring) ? strlen(topicname->cstring) : topicname->lenstring.len;
+	if ((len = MQTTSNPacket_len(MQTTSNSerialize_registerLength(topicnamelen))) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len);  /* write length */
+	writeChar(&ptr, MQTTSN_REGISTER);      /* write message type */
+
+	writeInt(&ptr, topicid);
+	writeInt(&ptr, packetid);
+
+	memcpy(ptr, (topicname->cstring) ? topicname->cstring : topicname->lenstring.data, topicnamelen);
+	ptr += topicnamelen;
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+/**
+  * Serializes the supplied register 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 topicid if sent by a gateway, contains the id for the topicname, otherwise 0
+  * @param packetid integer - the MQTT packet identifier
+  * @param return_code integer return code
+  * @return the length of the serialized data.  <= 0 indicates error
+  */
+int MQTTSNSerialize_regack(unsigned char* buf, int buflen, unsigned short topicid, unsigned short packetid,
+		unsigned char return_code)
+{
+	unsigned char *ptr = buf;
+	int len = 0;
+	int rc = 0;
+
+	FUNC_ENTRY;
+	if ((len = MQTTSNPacket_len(6)) > buflen)
+	{
+		rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	ptr += MQTTSNPacket_encode(ptr, len);  /* write length */
+	writeChar(&ptr, MQTTSN_REGACK);      /* write message type */
+
+	writeInt(&ptr, topicid);
+	writeInt(&ptr, packetid);
+	writeChar(&ptr, return_code);
+
+	rc = ptr - buf;
+exit:
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+