Implements private functions used by serializer and deserializer. DO NOT use these functions in your application. More...

#include <string.h>
#include <assert.h>
#include <stdbool.h>
#include <inttypes.h>
#include "core_mqtt_serializer.h"
#include "private/core_mqtt_serializer_private.h"
#include "core_mqtt_config_defaults.h"

Macros
#define	MQTT_VERSION_5 ( 5U )
	Version 5 has the value 5.

Functions
uint32_t	variableLengthEncodedSize (uint32_t length)
	Retrieve the size of the remaining length if it were to be encoded.

uint8_t *	encodeString (uint8_t pDestination, const char pSource, uint16_t sourceLength)
	Encode a string whose size is at maximum 16 bits in length.

MQTTStatus_t	decodeUserProp (const char *pPropertyKey, size_t pPropertyKeyLen, const char *pPropertyValue, size_t pPropertyValueLen, uint32_t pPropertyLength, uint8_t *pIndex)
	Validate the length and decode a user property.

MQTTStatus_t	decodeUint32t (uint32_t pProperty, uint32_t pPropertyLength, bool pUsed, uint8_t *pIndex)
	Validate the length and decode a 4 byte value.

MQTTStatus_t	decodeUint16t (uint16_t pProperty, uint32_t pPropertyLength, bool pUsed, uint8_t *pIndex)
	Validate the length and decode a 2 byte value.

MQTTStatus_t	decodeUint8t (uint8_t pProperty, uint32_t pPropertyLength, bool pUsed, uint8_t *pIndex)
	Validate the length and decode a 1 byte value.

MQTTStatus_t	decodeUtf8 (const char *pProperty, size_t pLength, uint32_t pPropertyLength, bool pUsed, uint8_t **pIndex)
	Validate the length and decode a utf 8 string.

MQTTStatus_t	decodeVariableLength (const uint8_t pBuffer, size_t bufferLength, uint32_t pLength)
	Decodes the variable length by reading a single byte at a time.

uint8_t *	encodeVariableLength (uint8_t *pDestination, uint32_t length)
	Encodes the remaining length of the packet using the variable length encoding scheme provided in the MQTT 5.0 specification.

uint8_t *	serializeAckFixed (uint8_t *pIndex, uint8_t packetType, uint16_t packetId, uint32_t remainingLength, MQTTSuccessFailReasonCode_t reasonCode)
	Serialize the fixed size part of the ack packet header.

uint8_t *	serializeConnectFixedHeader (uint8_t pIndex, const MQTTConnectInfo_t pConnectInfo, const MQTTPublishInfo_t *pWillInfo, uint32_t remainingLength)
	Serialize the fixed part of the connect packet header.

uint8_t *	serializeSubscribeHeader (uint32_t remainingLength, uint8_t *pIndex, uint16_t packetId)
	Serialize the fixed part of the subscribe packet header.

uint8_t *	serializeUnsubscribeHeader (uint32_t remainingLength, uint8_t *pIndex, uint16_t packetId)
	Serialize the fixed part of the unsubscribe packet header.

uint8_t *	serializeDisconnectFixed (uint8_t pIndex, const MQTTSuccessFailReasonCode_t pReasonCode, uint32_t remainingLength)
	Serialize the fixed size part of the disconnect packet header.

MQTTStatus_t	decodeSubackPropertyLength (const uint8_t pIndex, uint32_t remainingLength, uint32_t subackPropertyLength)
	Decodes the property length field in a SUBACK packet.

Detailed Description

Implements private functions used by serializer and deserializer. DO NOT use these functions in your application.

Note: These functions should not be called by the application or relied upon since their implementation can change. These are for internal use by the library only.

Function Documentation

◆ variableLengthEncodedSize()

uint32_t variableLengthEncodedSize ( uint32_t length )

Retrieve the size of the remaining length if it were to be encoded.

Parameters

[in] length The remaining length to be encoded.

Note: The length MUST be less than 268,435,455 as directed by the spec.

Returns: The size of the remaining length if it were to be encoded.

◆ encodeString()

uint8_t * encodeString	(	uint8_t *	pDestination,
		const char *	pSource,
		uint16_t	sourceLength
	)

Encode a string whose size is at maximum 16 bits in length.

Parameters

[out]	pDestination	Destination buffer for the encoding.
[in]	pSource	The source string to encode.
[in]	sourceLength	The length of the source string to encode.

Returns: A pointer to the end of the encoded string.

◆ decodeUserProp()

MQTTStatus_t decodeUserProp	(	const char **	pPropertyKey,
		size_t *	pPropertyKeyLen,
		const char **	pPropertyValue,
		size_t *	pPropertyValueLen,
		uint32_t *	pPropertyLength,
		uint8_t **	pIndex
	)

Validate the length and decode a user property.

Parameters

[out]	pPropertyKey	To store the decoded key.
[out]	pPropertyKeyLen	To store the decoded key length.
[out]	pPropertyValue	To store the decoded value.
[out]	pPropertyValueLen	To store the decoded value length.
[in,out]	pPropertyLength	Value of the remaining property length.
[in,out]	pIndex	Pointer to the current index of the buffer.

Returns: MQTTSuccess, MQTTBadResponse

◆ decodeUint32t()

MQTTStatus_t decodeUint32t	(	uint32_t *	pProperty,
		uint32_t *	pPropertyLength,
		bool *	pUsed,
		uint8_t **	pIndex
	)

Validate the length and decode a 4 byte value.

Parameters

[out]	pProperty	To store the decoded property.
[in,out]	pPropertyLength	Value of the remaining property length.
[in,out]	pUsed	Whether the property is decoded before.
[in,out]	pIndex	Pointer to the current index of the buffer.

Returns: MQTTSuccess, MQTTBadResponse

◆ decodeUint16t()

MQTTStatus_t decodeUint16t	(	uint16_t *	pProperty,
		uint32_t *	pPropertyLength,
		bool *	pUsed,
		uint8_t **	pIndex
	)

Validate the length and decode a 2 byte value.

Parameters

[out]	pProperty	To store the decoded property.
[in,out]	pPropertyLength	Value of the remaining property length.
[in,out]	pUsed	Whether the property is decoded before.
[in,out]	pIndex	Pointer to the current index of the buffer.

Returns: MQTTSuccess, MQTTBadResponse

◆ decodeUint8t()

MQTTStatus_t decodeUint8t	(	uint8_t *	pProperty,
		uint32_t *	pPropertyLength,
		bool *	pUsed,
		uint8_t **	pIndex
	)

Validate the length and decode a 1 byte value.

Parameters

[out]	pProperty	To store the decoded property.
[in,out]	pPropertyLength	Value of the remaining property length.
[in,out]	pUsed	Whether the property is decoded before.
[in,out]	pIndex	Pointer to the current index of the buffer.

Returns: MQTTSuccess, MQTTBadResponse

◆ decodeUtf8()

MQTTStatus_t decodeUtf8	(	const char **	pProperty,
		size_t *	pLength,
		uint32_t *	pPropertyLength,
		bool *	pUsed,
		uint8_t **	pIndex
	)

Validate the length and decode a utf 8 string.

Parameters

[out]	pProperty	To store the decoded string.
[out]	pLength	Size of the decoded utf-8 string.
[in,out]	pPropertyLength	Value of the remaining property length.
[in,out]	pUsed	Whether the property is decoded before.
[in,out]	pIndex	Pointer to the current index of the buffer.

Returns: MQTTSuccess, MQTTBadResponse

◆ decodeVariableLength()

MQTTStatus_t decodeVariableLength	(	const uint8_t *	pBuffer,
		size_t	bufferLength,
		uint32_t *	pLength
	)

Decodes the variable length by reading a single byte at a time.

Uses the algorithm provided in the spec.

Parameters

[in]	pBuffer	Pointer to the buffer.
[in]	bufferLength	Length of the remaining buffer.
[out]	pLength	Decoded variable length

Returns: MQTTSuccess if variable length and paramters are valid else MQTTBadResponse.

◆ encodeVariableLength()

uint8_t * encodeVariableLength	(	uint8_t *	pDestination,
		uint32_t	length
	)

Encodes the remaining length of the packet using the variable length encoding scheme provided in the MQTT 5.0 specification.

Parameters

[out]	pDestination	The destination buffer to store the encoded remaining length.
[in]	length	The remaining length to encode.

Returns: The location of the byte following the encoded value.

◆ serializeAckFixed()

uint8_t * serializeAckFixed	(	uint8_t *	pIndex,
		uint8_t	packetType,
		uint16_t	packetId,
		uint32_t	remainingLength,
		MQTTSuccessFailReasonCode_t	reasonCode
	)

Serialize the fixed size part of the ack packet header.

Parameters

[out]	pIndex	Pointer to the buffer where the header is to be serialized.
[in]	packetType	Type of publish ack
[in]	packetId	Packed identifier of the ack packet.
[in]	remainingLength	Remaining length of the ack packet.
[in]	reasonCode	Reason code for the ack packet.

Returns: A pointer to the end of the encoded string.

◆ serializeConnectFixedHeader()

uint8_t * serializeConnectFixedHeader	(	uint8_t *	pIndex,
		const MQTTConnectInfo_t *	pConnectInfo,
		const MQTTPublishInfo_t *	pWillInfo,
		uint32_t	remainingLength
	)

Serialize the fixed part of the connect packet header.

Parameters

[out]	pIndex	Pointer to the buffer where the header is to be serialized.
[in]	pConnectInfo	The connect information.
[in]	pWillInfo	The last will and testament information.
[in]	remainingLength	The remaining length of the packet to be serialized.

Returns: A pointer to the end of the encoded string.

◆ serializeSubscribeHeader()

uint8_t * serializeSubscribeHeader	(	uint32_t	remainingLength,
		uint8_t *	pIndex,
		uint16_t	packetId
	)

Serialize the fixed part of the subscribe packet header.

Parameters

[in]	remainingLength	The remaining length of the packet to be serialized.
[in]	pIndex	Pointer to the buffer where the header is to be serialized.
[in]	packetId	The packet ID to be serialized.

Returns: A pointer to the end of the encoded string.

◆ serializeUnsubscribeHeader()

uint8_t * serializeUnsubscribeHeader	(	uint32_t	remainingLength,
		uint8_t *	pIndex,
		uint16_t	packetId
	)

Serialize the fixed part of the unsubscribe packet header.

Parameters

[in]	remainingLength	The remaining length of the packet to be serialized.
[in]	pIndex	Pointer to the buffer where the header is to be serialized.
[in]	packetId	The packet ID to be serialized.

Returns: A pointer to the end of the encoded string.

◆ serializeDisconnectFixed()

uint8_t * serializeDisconnectFixed	(	uint8_t *	pIndex,
		const MQTTSuccessFailReasonCode_t *	pReasonCode,
		uint32_t	remainingLength
	)

Serialize the fixed size part of the disconnect packet header.

Parameters

[out]	pIndex	Pointer to the buffer where the header is to be serialized.
[in]	pReasonCode	Reason code for the disconnect packet.
[in]	remainingLength	Remaining length of the disconnect packet.

Returns: A pointer to the end of the encoded string.

◆ decodeSubackPropertyLength()

MQTTStatus_t decodeSubackPropertyLength	(	const uint8_t *	pIndex,
		uint32_t	remainingLength,
		uint32_t *	subackPropertyLength
	)

Decodes the property length field in a SUBACK packet.

Parameters

[in]	pIndex	Pointer to the start of the properties in the SUBACK packet.
[in]	remainingLength	The remaining length of the MQTT packet being parsed, without Packet ID.
[out]	subackPropertyLength	The decoded property length including the size of its encoded representation.

Returns: MQTTSuccess if the property length is successfully decoded; MQTTBadResponse if the decoded property length is greater than the remaining length.

Macros

Functions

Detailed Description

Function Documentation

◆ variableLengthEncodedSize()

◆ encodeString()

◆ decodeUserProp()

◆ decodeUint32t()

◆ decodeUint16t()

◆ decodeUint8t()

◆ decodeUtf8()

◆ decodeVariableLength()

◆ encodeVariableLength()

◆ serializeAckFixed()

◆ serializeConnectFixedHeader()

◆ serializeSubscribeHeader()

◆ serializeUnsubscribeHeader()

◆ serializeDisconnectFixed()

◆ decodeSubackPropertyLength()