Diff: MQTT/MQTTPacket/MQTTSerializePublish.c

Revision:

0:238f0d0c0ba3

diff -r 000000000000 -r 238f0d0c0ba3 MQTT/MQTTPacket/MQTTSerializePublish.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MQTT/MQTTPacket/MQTTSerializePublish.c	Fri Mar 26 16:15:14 2021 +0000
@@ -0,0 +1,168 @@
+/*******************************************************************************
+ * 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
+ *    Ian Craggs - fix for https://bugs.eclipse.org/bugs/show_bug.cgi?id=453144
+ *******************************************************************************/
+
+#include "MQTTPacket.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 MQTTSerialize_publishLength(int qos, MQTTString topicName, int payloadlen)
+{
+	int len = 0;
+
+	len += 2 + MQTTstrlen(topicName) + payloadlen;
+	if (qos > 0)
+		len += 2; /* packetid */
+	return 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 topicName MQTTString - 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 MQTTSerialize_publish(unsigned char* buf, int buflen, unsigned char dup, int qos, unsigned char retained, unsigned short packetid,
+		MQTTString topicName, unsigned char* payload, int payloadlen)
+{
+	unsigned char *ptr = buf;
+	MQTTHeader header = {0};
+	int rem_len = 0;
+	int rc = 0;
+
+	FUNC_ENTRY;
+	if (MQTTPacket_len(rem_len = MQTTSerialize_publishLength(qos, topicName, payloadlen)) > buflen)
+	{
+		rc = MQTTPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+
+	header.bits.type = PUBLISH;
+	header.bits.dup = dup;
+	header.bits.qos = qos;
+	header.bits.retain = retained;
+	writeChar(&ptr, header.byte); /* write header */
+
+	ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */;
+
+	writeMQTTString(&ptr, topicName);
+
+	if (qos > 0)
+		writeInt(&ptr, packetid);
+
+	memcpy(ptr, payload, payloadlen);
+	ptr += payloadlen;
+
+	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 packet type
+  * @param dup the MQTT dup flag
+  * @param packetid the MQTT packet identifier
+  * @return serialized length, or error if 0
+  */
+int MQTTSerialize_ack(unsigned char* buf, int buflen, unsigned char packettype, unsigned char dup, unsigned short packetid)
+{
+	MQTTHeader header = {0};
+	int rc = 0;
+	unsigned char *ptr = buf;
+
+	FUNC_ENTRY;
+	if (buflen < 4)
+	{
+		rc = MQTTPACKET_BUFFER_TOO_SHORT;
+		goto exit;
+	}
+	header.bits.type = packettype;
+	header.bits.dup = dup;
+	header.bits.qos = (packettype == PUBREL) ? 1 : 0;
+	writeChar(&ptr, header.byte); /* write header */
+
+	ptr += MQTTPacket_encode(ptr, 2); /* write remaining length */
+	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 MQTTSerialize_puback(unsigned char* buf, int buflen, unsigned short packetid)
+{
+	return MQTTSerialize_ack(buf, buflen, PUBACK, 0, 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 MQTTSerialize_pubrel(unsigned char* buf, int buflen, unsigned char dup, unsigned short packetid)
+{
+	return MQTTSerialize_ack(buf, buflen, PUBREL, dup, 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 MQTTSerialize_pubcomp(unsigned char* buf, int buflen, unsigned short packetid)
+{
+	return MQTTSerialize_ack(buf, buflen, PUBCOMP, 0, packetid);
+}
+