MQTTPacket.h File Reference

#include "MQTTConnect.h"
#include "MQTTPublish.h"
#include "MQTTSubscribe.h"
#include "MQTTUnsubscribe.h"
#include "MQTTFormat.h"

Data Structures
union	MQTTHeader
	Bitfields for the MQTT header byte. More...
struct	MQTTLenString
struct	MQTTString
struct	MQTTTransport

Macros
#define	DLLExport
#define	DLLImport
#define	MQTTString_initializer   {NULL, {0, NULL}}

Enumerations
enum	errors {   MQTTPACKET_BUFFER_TOO_SHORT = -2,   MQTTPACKET_READ_ERROR = -1,   MQTTPACKET_READ_COMPLETE }
enum	msgTypes {   CONNECT = 1,   CONNACK,   PUBLISH,   PUBACK,   PUBREC,   PUBREL,   PUBCOMP,   SUBSCRIBE,   SUBACK,   UNSUBSCRIBE,   UNSUBACK,   PINGREQ,   PINGRESP,   DISCONNECT }

Functions
int	MQTTDeserialize_ack (unsigned char *packettype, unsigned char *dup, unsigned short *packetid, unsigned char *buf, int buflen)
	Deserializes the supplied (wire) buffer into an ack. More...
int	MQTTPacket_decode (int(*getcharfn)(unsigned char *, int), int *value)
	Decodes the message length according to the MQTT algorithm. More...
int	MQTTPacket_decodeBuf (unsigned char *buf, int *value)
int	MQTTPacket_encode (unsigned char *buf, int length)
	Encodes the message length according to the MQTT algorithm. More...
int	MQTTPacket_equals (MQTTString *a, char *b)
	Compares an MQTTString to a C string. More...
int	MQTTPacket_len (int rem_len)
DLLExport int	MQTTPacket_read (unsigned char *buf, int buflen, int(*getfn)(unsigned char *, int))
	Helper function to read packet data from some source into a buffer. More...
int	MQTTPacket_readnb (unsigned char *buf, int buflen, MQTTTransport *trp)
	Helper function to read packet data from some source into a buffer, non-blocking. More...
int	MQTTSerialize_ack (unsigned char *buf, int buflen, unsigned char type, unsigned char dup, unsigned short packetid)
	Serializes the ack packet into the supplied buffer. More...
int	MQTTstrlen (MQTTString mqttstring)
	Return the length of the MQTTstring - C string if there is one, otherwise the length delimited string. More...
char	readChar (unsigned char **pptr)
	Reads one character from the input buffer. More...
int	readInt (unsigned char **pptr)
	Calculates an integer from two bytes read from the input buffer. More...
int	readMQTTLenString (MQTTString *mqttstring, unsigned char **pptr, unsigned char *enddata)
void	writeChar (unsigned char **pptr, char c)
	Writes one character to an output buffer. More...
void	writeCString (unsigned char **pptr, const char *string)
	Writes a "UTF" string to an output buffer. More...
void	writeInt (unsigned char **pptr, int anInt)
	Writes an integer as 2 bytes to an output buffer. More...
void	writeMQTTString (unsigned char **pptr, MQTTString mqttstring)

#define DLLExport

#define DLLImport

#define MQTTString_initializer   {NULL, {0, NULL}}

Referenced by MQTTFormat_toClientString(), MQTTFormat_toServerString(), MQTTPublish(), MQTTSubscribe(), and MQTTUnsubscribe().

enum errors

Enumerator
MQTTPACKET_BUFFER_TOO_SHORT
MQTTPACKET_READ_ERROR
MQTTPACKET_READ_COMPLETE

enum msgTypes

Enumerator
CONNECT
CONNACK
PUBLISH
PUBACK
PUBREC
PUBREL
PUBCOMP
SUBSCRIBE
SUBACK
UNSUBSCRIBE
UNSUBACK
PINGREQ
PINGRESP
DISCONNECT

int MQTTDeserialize_ack	(	unsigned char *	packettype,
		unsigned char *	dup,
		unsigned short *	packetid,
		unsigned char *	buf,
		int	buflen
	)

Deserializes the supplied (wire) buffer into an ack.

Parameters

packettype	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

References MQTTHeader::bits, MQTTHeader::byte, MQTTHeader::dup, FUNC_ENTRY, FUNC_EXIT_RC, header, MQTTPacket_decodeBuf(), NULL, readChar(), readInt(), and MQTTHeader::type.

Referenced by cycle(), MQTTDeserialize_unsuback(), MQTTFormat_toClientString(), MQTTFormat_toServerString(), and MQTTPublish().

int MQTTPacket_decode	(	int(*)(unsigned 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

References FUNC_ENTRY, FUNC_EXIT_RC, MAX_NO_OF_REMAINING_LENGTH_BYTES, and MQTTPACKET_READ_ERROR.

Referenced by MQTTPacket_decodeBuf(), and MQTTPacket_read().

int MQTTPacket_decodeBuf	(	unsigned char *	buf,
		int *	value
	)

References bufchar(), and MQTTPacket_decode().

Referenced by MQTTDeserialize_ack(), MQTTDeserialize_connack(), MQTTDeserialize_connect(), MQTTDeserialize_publish(), MQTTDeserialize_suback(), MQTTDeserialize_subscribe(), MQTTDeserialize_unsubscribe(), MQTTFormat_toClientString(), and MQTTFormat_toServerString().

int MQTTPacket_encode	(	unsigned 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

References FUNC_ENTRY, and FUNC_EXIT_RC.

Referenced by MQTTPacket_read(), MQTTPacket_readnb(), MQTTSerialize_ack(), MQTTSerialize_connack(), MQTTSerialize_connect(), MQTTSerialize_publish(), MQTTSerialize_suback(), MQTTSerialize_subscribe(), MQTTSerialize_unsuback(), MQTTSerialize_unsubscribe(), MQTTSerialize_zero(), and readPacket().

int MQTTPacket_equals	(	MQTTString *	a,
		char *	bptr
	)

Compares an MQTTString to a C string.

Parameters

a	the MQTTString to compare
bptr	the C string to compare

Returns

boolean - equal or not

References MQTTString::cstring, MQTTLenString::data, MQTTLenString::len, and MQTTString::lenstring.

Referenced by deliverMessage().

int MQTTPacket_len

(

int

rem_len

)

Referenced by MQTTSerialize_connect(), MQTTSerialize_publish(), MQTTSerialize_subscribe(), and MQTTSerialize_unsubscribe().

DLLExport int MQTTPacket_read	(	unsigned char *	buf,
		int	buflen,
		int(*)(unsigned 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

Note

the whole message must fit into the caller's buffer

References MQTTHeader::bits, MQTTHeader::byte, header, MQTTPacket_decode(), MQTTPacket_encode(), and MQTTHeader::type.

int MQTTPacket_readnb	(	unsigned char *	buf,
		int	buflen,
		MQTTTransport *	trp
	)

Helper function to read packet data from some source into a buffer, non-blocking.

Parameters

buf	the buffer into which the packet will be serialized
buflen	the length in bytes of the supplied buffer
trp	pointer to a transport structure holding what is needed to solve getting data from it

Returns

integer MQTT packet type, 0 for call again, or -1 on error

Note

the whole message must fit into the caller's buffer

References MQTTHeader::bits, MQTTHeader::byte, MQTTTransport::getfn, header, MQTTTransport::len, MQTTPacket_decodenb(), MQTTPacket_encode(), MQTTPACKET_READ_ERROR, MQTTTransport::rem_len, MQTTTransport::sck, MQTTTransport::state, and MQTTHeader::type.

int MQTTSerialize_ack	(	unsigned char *	buf,
		int	buflen,
		unsigned char	packettype,
		unsigned char	dup,
		unsigned short	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	the MQTT packet type
dup	the MQTT dup flag
packetid	the MQTT packet identifier

Returns

serialized length, or error if 0

References MQTTHeader::bits, MQTTHeader::byte, MQTTHeader::dup, FUNC_ENTRY, FUNC_EXIT_RC, header, MQTTPACKET_BUFFER_TOO_SHORT, MQTTPacket_encode(), ptr, PUBREL, MQTTHeader::qos, MQTTHeader::type, writeChar(), and writeInt().

Referenced by cycle(), MQTTSerialize_puback(), MQTTSerialize_pubcomp(), and MQTTSerialize_pubrel().

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

References MQTTString::cstring, MQTTLenString::len, and MQTTString::lenstring.

Referenced by MQTTSerialize_connectLength(), MQTTSerialize_publishLength(), MQTTSerialize_subscribeLength(), and MQTTSerialize_unsubscribeLength().

char readChar

(

unsigned 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

Referenced by MQTTDeserialize_ack(), MQTTDeserialize_connack(), MQTTDeserialize_connect(), MQTTDeserialize_publish(), MQTTDeserialize_suback(), MQTTDeserialize_subscribe(), and MQTTDeserialize_unsubscribe().

int readInt

(

unsigned 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

References ptr.

Referenced by MQTTDeserialize_ack(), MQTTDeserialize_connect(), MQTTDeserialize_publish(), MQTTDeserialize_suback(), MQTTDeserialize_subscribe(), MQTTDeserialize_unsubscribe(), and readMQTTLenString().

int readMQTTLenString	(	MQTTString *	mqttstring,
		unsigned char **	pptr,
		unsigned 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

References MQTTString::cstring, MQTTLenString::data, FUNC_ENTRY, FUNC_EXIT_RC, MQTTLenString::len, MQTTString::lenstring, NULL, and readInt().

Referenced by MQTTDeserialize_connect(), MQTTDeserialize_publish(), MQTTDeserialize_subscribe(), and MQTTDeserialize_unsubscribe().

void writeChar	(	unsigned 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

Referenced by MQTTSerialize_ack(), MQTTSerialize_connack(), MQTTSerialize_connect(), MQTTSerialize_publish(), MQTTSerialize_suback(), MQTTSerialize_subscribe(), MQTTSerialize_unsuback(), MQTTSerialize_unsubscribe(), and MQTTSerialize_zero().

void writeCString	(	unsigned char **	pptr,
		const 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

References writeInt().

Referenced by MQTTSerialize_connect(), and writeMQTTString().

void writeInt	(	unsigned 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

Referenced by MQTTSerialize_ack(), MQTTSerialize_connect(), MQTTSerialize_publish(), MQTTSerialize_suback(), MQTTSerialize_subscribe(), MQTTSerialize_unsuback(), MQTTSerialize_unsubscribe(), writeCString(), and writeMQTTString().

void writeMQTTString	(	unsigned char **	pptr,
		MQTTString	mqttstring
	)

References MQTTString::cstring, MQTTLenString::data, MQTTLenString::len, MQTTString::lenstring, writeCString(), and writeInt().

Referenced by MQTTSerialize_connect(), MQTTSerialize_publish(), MQTTSerialize_subscribe(), and MQTTSerialize_unsubscribe().