Functions

Functions
int	MQTTSerialize_connectLength (MQTTPacket_connectData *options)
int	MQTTSerialize_connect (char *buf, int buflen, MQTTPacket_connectData *options)
int	MQTTDeserialize_connack (int *connack_rc, char *buf, int buflen)
int	MQTTSerialize_disconnect (char *buf, int buflen)
int	MQTTPacket_checkVersion (MQTTString *protocol, int version)
int	MQTTDeserialize_connect (MQTTPacket_connectData *data, char *buf, int len)
int	MQTTSerialize_connack (char *buf, int buflen, int connack_rc)
int	MQTTDeserialize_publish (int *dup, int *qos, int *retained, int *packetid, MQTTString *topicName, char **payload, int *payloadlen, char *buf, int buflen)
int	MQTTDeserialize_ack (int *type, int *dup, int *packetid, char *buf, int buflen)
int	MQTTPacket_encode (char *buf, int length)
int	MQTTPacket_decode (int(*getcharfn)(char *, int), int *value)
int	readInt (char **pptr)
char	readChar (char **pptr)
void	writeChar (char **pptr, char c)
void	writeInt (char **pptr, int anInt)
void	writeCString (char **pptr, char *string)
int	readMQTTLenString (MQTTString *mqttstring, char **pptr, char *enddata)
int	MQTTstrlen (MQTTString mqttstring)
int	MQTTPacket_read (char *buf, int buflen, int(*getfn)(char *, int))
int	MQTTSerialize_publishLength (int qos, MQTTString topicName, int payloadlen)
int	MQTTSerialize_publish (char *buf, int buflen, int dup, int qos, int retained, int packetid, MQTTString topicName, char *payload, int payloadlen)
int	MQTTSerialize_ack (char *buf, int buflen, int type, int dup, int packetid)
int	MQTTSerialize_puback (char *buf, int buflen, int packetid)
int	MQTTSerialize_pubrel (char *buf, int buflen, int dup, int packetid)
int	MQTTSerialize_pubcomp (char *buf, int buflen, int packetid)
int	MQTTSerialize_subscribeLength (int count, MQTTString topicFilters[])
int	MQTTSerialize_subscribe (char *buf, int buflen, int dup, int packetid, int count, MQTTString topicFilters[], int requestedQoSs[])
int	MQTTDeserialize_suback (int *packetid, int maxcount, int *count, int grantedQoSs[], char *buf, int buflen)
int	MQTTDeserialize_subscribe (int *dup, int *packetid, int maxcount, int *count, MQTTString topicFilters[], int requestedQoSs[], char *buf, int buflen)
int	MQTTSerialize_suback (char *buf, int buflen, int packetid, int count, int *grantedQoSs)
int	MQTTSerialize_unsubscribeLength (int count, MQTTString topicFilters[])
int	MQTTSerialize_unsubscribe (char *buf, int buflen, int dup, int packetid, int count, MQTTString topicFilters[])
int	MQTTDeserialize_unsuback (int *packetid, char *buf, int buflen)
int	MQTTDeserialize_unsubscribe (int *dup, int *packetid, int maxcount, int *count, MQTTString topicFilters[], char *buf, int len)
int	MQTTSerialize_unsuback (char *buf, int buflen, int packetid)

Detailed Description

Function Documentation

int MQTTDeserialize_ack	(	int *	type,
		int *	dup,
		int *	packetid,
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into an ack

Parameters

type	returned integer - the MQTT packet type
dup	returned integer - the MQTT dup flag
packetid	returned integer - the MQTT packet identifier
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success, 0 is failure

int MQTTDeserialize_connack	(	int *	connack_rc,
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into connack data - return code

Parameters

connack_rc	returned integer value of the connack return code
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success, 0 is failure

int MQTTDeserialize_connect	(	MQTTPacket_connectData *	data,
		char *	buf,
		int	len
	)

Deserializes the supplied (wire) buffer into connect data structure

Parameters

data	the connect data structure to be filled out
buf	the raw buffer data, of the correct length determined by the remaining length field
len	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success, 0 is failure

int MQTTDeserialize_publish	(	int *	dup,
		int *	qos,
		int *	retained,
		int *	packetid,
		MQTTString *	topicName,
		char **	payload,
		int *	payloadlen,
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into publish data

Parameters

dup	returned integer - the MQTT dup flag
qos	returned integer - the MQTT QoS value
retained	returned integer - the MQTT retained flag
packetid	returned integer - the MQTT packet identifier
topicName	returned MQTTString - the MQTT topic in the publish
payload	returned byte buffer - the MQTT publish payload
payloadlen	returned integer - the length of the MQTT payload
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success

int MQTTDeserialize_suback	(	int *	packetid,
		int	maxcount,
		int *	count,
		int	grantedQoSs[],
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into suback data

Parameters

packetid	returned integer - the MQTT packet identifier
maxcount	- the maximum number of members allowed in the grantedQoSs array
count	returned integer - number of members in the grantedQoSs array
grantedQoSs	returned array of integers - the granted qualities of service
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success, 0 is failure

int MQTTDeserialize_subscribe	(	int *	dup,
		int *	packetid,
		int	maxcount,
		int *	count,
		MQTTString	topicFilters[],
		int	requestedQoSs[],
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into subscribe data

Parameters

dup	integer returned - the MQTT dup flag
packetid	integer returned - the MQTT packet identifier
maxcount	- the maximum number of members allowed in the topicFilters and requestedQoSs arrays
count	- number of members in the topicFilters and requestedQoSs arrays
topicFilters	- array of topic filter names
requestedQoSs	- array of requested QoS
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

the length of the serialized data. <= 0 indicates error

int MQTTDeserialize_unsuback	(	int *	packetid,
		char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into unsuback data

Parameters

packetid	returned integer - the MQTT packet identifier
buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer

Returns

error code. 1 is success, 0 is failure

int MQTTDeserialize_unsubscribe	(	int *	dup,
		int *	packetid,
		int	maxcount,
		int *	count,
		MQTTString	topicFilters[],
		char *	buf,
		int	len
	)

Deserializes the supplied (wire) buffer into unsubscribe data

Parameters

dup	integer returned - the MQTT dup flag
packetid	integer returned - the MQTT packet identifier
maxcount	- the maximum number of members allowed in the topicFilters and requestedQoSs arrays
count	- number of members in the topicFilters and requestedQoSs arrays
topicFilters	- array of topic filter names
buf	the raw buffer data, of the correct length determined by the remaining length field
len	the length in bytes of the data in the supplied buffer

Returns

the length of the serialized data. <= 0 indicates error

int MQTTPacket_checkVersion	(	MQTTString *	protocol,
		int	version
	)

Validates MQTT protocol name and version combinations

Parameters

protocol	the MQTT protocol name as an MQTTString
version	the MQTT protocol version number, as in the connect packet

Returns

correct MQTT combination? 1 is true, 0 is false

int MQTTPacket_decode	(	int(*)(char *, int)	getcharfn,
		int *	value
	)

Decodes the message length according to the MQTT algorithm

Parameters

getcharfn	pointer to function to read the next character from the data source
value	the decoded length returned

Returns

the number of bytes read from the socket

int MQTTPacket_encode	(	char *	buf,
		int	length
	)

Encodes the message length according to the MQTT algorithm

Parameters

buf	the buffer into which the encoded data is written
length	the length to be encoded

Returns

the number of bytes written to buffer

int MQTTPacket_read	(	char *	buf,
		int	buflen,
		int(*)(char *, int)	getfn
	)

Helper function to read packet data from some source into a buffer

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
getfn	pointer to a function which will read any number of bytes from the needed source

Returns

integer MQTT packet type, or -1 on error

int MQTTSerialize_ack	(	char *	buf,
		int	buflen,
		int	type,
		int	dup,
		int	packetid
	)

Serializes the ack packet into the supplied buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
type	integer - the MQTT packet type
dup	integer - the MQTT dup flag
packetid	integer - the MQTT packet identifier

Returns

serialized length, or error if 0

int MQTTSerialize_connack	(	char *	buf,
		int	buflen,
		int	connack_rc
	)

Serializes the connack packet into the supplied buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
connack_rc	the integer connack return code to be used

Returns

serialized length, or error if 0

int MQTTSerialize_connect	(	char *	buf,
		int	buflen,
		MQTTPacket_connectData *	options
	)

Serializes the connect options into the buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
options	the options to be used to build the connect packet

Returns

serialized length, or error if 0

int MQTTSerialize_connectLength

(

MQTTPacket_connectData *

options

)

Determines the length of the MQTT connect packet that would be produced using the supplied connect options.

Parameters

options

the options to be used to build the connect packet

Returns

the length of buffer needed to contain the serialized version of the packet

int MQTTSerialize_disconnect	(	char *	buf,
		int	buflen
	)

Serializes a disconnect packet into the supplied buffer, ready for writing to a socket

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer, to avoid overruns

Returns

serialized length, or error if 0

int MQTTSerialize_puback	(	char *	buf,
		int	buflen,
		int	packetid
	)

Serializes a puback packet into the supplied buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
packetid	integer - the MQTT packet identifier

Returns

serialized length, or error if 0

int MQTTSerialize_pubcomp	(	char *	buf,
		int	buflen,
		int	packetid
	)

Serializes a pubrel packet into the supplied buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
packetid	integer - the MQTT packet identifier

Returns

serialized length, or error if 0

int MQTTSerialize_publish	(	char *	buf,
		int	buflen,
		int	dup,
		int	qos,
		int	retained,
		int	packetid,
		MQTTString	topicName,
		char *	payload,
		int	payloadlen
	)

Serializes the supplied publish data into the supplied buffer, ready for sending

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
dup	integer - the MQTT dup flag
qos	integer - the MQTT QoS value
retained	integer - the MQTT retained flag
packetid	integer - the MQTT packet identifier
topicName	MQTTString - the MQTT topic in the publish
payload	byte buffer - the MQTT publish payload
payloadlen	integer - the length of the MQTT payload

Returns

the length of the serialized data. <= 0 indicates error

int MQTTSerialize_publishLength	(	int	qos,
		MQTTString	topicName,
		int	payloadlen
	)

Determines the length of the MQTT publish packet that would be produced using the supplied parameters

Parameters

qos	the MQTT QoS of the publish (packetid is omitted for QoS 0)
topicName	the topic name to be used in the publish
payloadlen	the length of the payload to be sent

Returns

the length of buffer needed to contain the serialized version of the packet

int MQTTSerialize_pubrel	(	char *	buf,
		int	buflen,
		int	dup,
		int	packetid
	)

Serializes a pubrel packet into the supplied buffer.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
dup	integer - the MQTT dup flag
packetid	integer - the MQTT packet identifier

Returns

serialized length, or error if 0

int MQTTSerialize_suback	(	char *	buf,
		int	buflen,
		int	packetid,
		int	count,
		int *	grantedQoSs
	)

Serializes the supplied suback data into the supplied buffer, ready for sending

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
packetid	integer - the MQTT packet identifier
count	- number of members in the grantedQoSs array
grantedQoSs	- array of granted QoS

Returns

the length of the serialized data. <= 0 indicates error

int MQTTSerialize_subscribe	(	char *	buf,
		int	buflen,
		int	dup,
		int	packetid,
		int	count,
		MQTTString	topicFilters[],
		int	requestedQoSs[]
	)

Serializes the supplied subscribe data into the supplied buffer, ready for sending

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied bufferr
dup	integer - the MQTT dup flag
packetid	integer - the MQTT packet identifier
count	- number of members in the topicFilters and reqQos arrays
topicFilters	- array of topic filter names
requestedQoSs	- array of requested QoS

Returns

the length of the serialized data. <= 0 indicates error

int MQTTSerialize_subscribeLength	(	int	count,
		MQTTString	topicFilters[]
	)

Determines the length of the MQTT subscribe packet that would be produced using the supplied parameters

Parameters

count	the number of topic filter strings in topicFilters
topicFilters	the array of topic filter strings to be used in the publish

Returns

the length of buffer needed to contain the serialized version of the packet

int MQTTSerialize_unsuback	(	char *	buf,
		int	buflen,
		int	packetid
	)

Serializes the supplied unsuback data into the supplied buffer, ready for sending

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
packetid	integer - the MQTT packet identifier

Returns

the length of the serialized data. <= 0 indicates error

int MQTTSerialize_unsubscribe	(	char *	buf,
		int	buflen,
		int	dup,
		int	packetid,
		int	count,
		MQTTString	topicFilters[]
	)

Serializes the supplied unsubscribe data into the supplied buffer, ready for sending

Parameters

buf	the raw buffer data, of the correct length determined by the remaining length field
buflen	the length in bytes of the data in the supplied buffer
dup	integer - the MQTT dup flag
packetid	integer - the MQTT packet identifier
count	- number of members in the topicFilters array
topicFilters	- array of topic filter names

Returns

the length of the serialized data. <= 0 indicates error

int MQTTSerialize_unsubscribeLength	(	int	count,
		MQTTString	topicFilters[]
	)

Determines the length of the MQTT unsubscribe packet that would be produced using the supplied parameters

Parameters

count	the number of topic filter strings in topicFilters
topicFilters	the array of topic filter strings to be used in the publish

Returns

the length of buffer needed to contain the serialized version of the packet

int MQTTstrlen

(

MQTTString

mqttstring

)

Return the length of the MQTTstring - C string if there is one, otherwise the length delimited string

Parameters

mqttstring

the string to return the length of

Returns

the length of the string

char readChar

(

char **

pptr

)

Reads one character from the input buffer.

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned

Returns

the character read

int readInt

(

char **

pptr

)

Calculates an integer from two bytes read from the input buffer

Parameters

pptr	pointer to the input buffer - incremented by the number of bytes used & returned

Returns

the integer value calculated

int readMQTTLenString	(	MQTTString *	mqttstring,
		char **	pptr,
		char *	enddata
	)

Parameters

mqttstring	the MQTTString structure into which the data is to be read
pptr	pointer to the output buffer - incremented by the number of bytes used & returned
enddata	pointer to the end of the data: do not read beyond

Returns

1 if successful, 0 if not

void writeChar	(	char **	pptr,
		char	c
	)

Writes one character to an output buffer.

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
c	the character to write

void writeCString	(	char **	pptr,
		char *	string
	)

Writes a "UTF" string to an output buffer. Converts C string to length-delimited.

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
string	the C string to write

void writeInt	(	char **	pptr,
		int	anInt
	)

Writes an integer as 2 bytes to an output buffer.

Parameters

pptr	pointer to the output buffer - incremented by the number of bytes used & returned
anInt	the integer to write