point_one::rtcm::RTCMFramer Class Reference

Detailed Description

Frame and validate incoming RTCM 3 messages.

This class locates and validates RTCM 3 messages within a stream of binary data. Data may be stored in an internally allocated buffer, or in an external buffer supplied by the user.

The callback function provided to SetMessageCallback() will be called each time a complete message is received. Any messages that do not pass the CRC check, or that are too big to be stored in the data buffer, will be discarded.

Example usage:

void MessageReceived(uint16_t message_type, const void* data, size_t data_len) {
  ...
}
 
RTCMFramer framer(1024);
framer.SetMessageCallback(MessageReceived);
framer.OnData(my_data, my_data_size);

Definition at line 39 of file rtcm_framer.h.

#include <point_one/rtcm/rtcm_framer.h>

Public Types
using	MessageCallback = void(*)(uint16_t, const void *, size_t)

Public Member Functions
	RTCMFramer ()=default
	Construct a framer instance with no buffer allocated. More...
	RTCMFramer (const RTCMFramer &)=delete
	RTCMFramer (RTCMFramer &&)=delete
	RTCMFramer (size_t capacity_bytes)
	Construct a framer instance with an internally allocated buffer. More...
	RTCMFramer (void *buffer, size_t capacity_bytes)
	Construct a framer instance with a user-specified buffer. More...
	~RTCMFramer ()
uint32_t	GetNumDecodedMessages () const
	Get the number of decoded messages. More...
uint32_t	GetNumErrors () const
	Get the number of preamble synchronizations that resulted in errors. More...
size_t	OnData (const uint8_t *buffer, size_t length_bytes)
	Process incoming data. More...
RTCMFramer &	operator= (const RTCMFramer &)=delete
RTCMFramer &	operator= (RTCMFramer &&)=delete
void	Reset ()
	Reset the framer and discard all pending data. More...
void	SetBuffer (void *buffer, size_t capacity_bytes)
	Set the buffer to use for message framing. More...
void	SetMessageCallback (MessageCallback callback)
	Specify a function to be called when a message is framed. More...
void	WarnOnError (bool enabled)
	Enable/disable warnings for CRC and "message too large" failures. More...

Private Types
enum	State { State::SYNC = 0, State::HEADER = 1, State::DATA = 2 }

Private Member Functions
void	ClearManagedBuffer ()
	Free the buffer_ if it's being managed internally. More...
int32_t	OnByte (bool quiet)
	Process a single byte. More...
uint32_t	Resync ()
	Perform a resynchronization operation starting at buffer_[1]. More...

Private Attributes
uint8_t *	buffer_ {nullptr}
MessageCallback	callback_ = nullptr
uint32_t	capacity_bytes_ {0}
size_t	current_message_size_ {0}
uint32_t	decoded_msg_count_ {0}
uint32_t	error_count_ {0}
bool	is_buffer_managed_ = false
uint32_t	next_byte_index_ {0}
State	state_ {State::SYNC}
bool	warn_on_error_ = true

Member Typedef Documentation

MessageCallback

using point_one::rtcm::RTCMFramer::MessageCallback = void (*)(uint16_t, const void*, size_t)

Definition at line 41 of file rtcm_framer.h.

Member Enumeration Documentation

State

enum point_one::rtcm::RTCMFramer::State

strongprivate

Enumerator
SYNC
HEADER
DATA

Definition at line 147 of file rtcm_framer.h.

Constructor & Destructor Documentation

RTCMFramer() [1/5]

point_one::rtcm::RTCMFramer::RTCMFramer ( )

default

Construct a framer instance with no buffer allocated.

Note

You must call SetBuffer() to assign a buffer, otherwise all incoming data will be discarded.

RTCMFramer() [2/5]

point_one::rtcm::RTCMFramer::RTCMFramer ( size_t  capacity_bytes )

inlineexplicit

Construct a framer instance with an internally allocated buffer.

Parameters

capacity_bytes

The maximum framing buffer capacity (in bytes).

Definition at line 57 of file rtcm_framer.h.

RTCMFramer() [3/5]

RTCMFramer::RTCMFramer	(	void *	buffer,
		size_t	capacity_bytes
	)

Construct a framer instance with a user-specified buffer.

Postcondition

buffer must exist for the lifetime of this instance.

Parameters

buffer	The framing buffer to use. Set to nullptr to allocate a buffer internally.
capacity_bytes	The maximum framing buffer capacity (in bytes).

Definition at line 176 of file rtcm_framer.cc.

~RTCMFramer()

RTCMFramer::~RTCMFramer

(

)

Definition at line 190 of file rtcm_framer.cc.

RTCMFramer() [4/5]

point_one::rtcm::RTCMFramer::RTCMFramer ( const RTCMFramer &  )

delete

RTCMFramer() [5/5]

point_one::rtcm::RTCMFramer::RTCMFramer ( RTCMFramer &&  )

delete

Member Function Documentation

ClearManagedBuffer()

void RTCMFramer::ClearManagedBuffer ( )

private

Free the buffer_ if it's being managed internally.

Definition at line 527 of file rtcm_framer.cc.

GetNumDecodedMessages()

uint32_t point_one::rtcm::RTCMFramer::GetNumDecodedMessages ( ) const

inline

Get the number of decoded messages.

Returns

The number of RTCM messages successfully decoded.

Definition at line 133 of file rtcm_framer.h.

GetNumErrors()

uint32_t point_one::rtcm::RTCMFramer::GetNumErrors ( ) const

inline

Get the number of preamble synchronizations that resulted in errors.

This is not an accurate count of failed messages since the RTCM preamble is not unique and may appear anywhere in the data stream, but gives an approximate count.

Returns

The number of length or CRC failures found in decoding so far.

Definition at line 144 of file rtcm_framer.h.

OnByte()

int32_t RTCMFramer::OnByte ( bool  quiet )

private

Process a single byte.

Precondition

The byte must be located at buffer_[next_byte_index_ - 1].

Parameters

quiet

If true, suppress failure warning messages.

Returns

The total size of all valid, complete messages, 0 if no messages were completed, or <0 CRC or "message too large" error.

Transport header (big endian): Preamble = 8 bits Reserved = 6 bits Message Length = 10 bits

Definition at line 277 of file rtcm_framer.cc.

OnData()

size_t RTCMFramer::OnData	(	const uint8_t *	buffer,
		size_t	length_bytes
	)

Process incoming data.

Parameters

buffer	A buffer containing data to be framed.
length_bytes	The number of bytes to be framed.

Returns

The total size of all valid, complete messages, or 0 if no messages were completed.

Definition at line 237 of file rtcm_framer.cc.

operator=() [1/2]

RTCMFramer& point_one::rtcm::RTCMFramer::operator= ( const RTCMFramer &  )

delete

operator=() [2/2]

RTCMFramer& point_one::rtcm::RTCMFramer::operator= ( RTCMFramer &&  )

delete

Reset()

void RTCMFramer::Reset

(

)

Reset the framer and discard all pending data.

Definition at line 228 of file rtcm_framer.cc.

Resync()

uint32_t RTCMFramer::Resync ( )

private

Perform a resynchronization operation starting at buffer_[1].

Returns

The total size of all valid, complete messages, or 0 if no messages were completed.

Definition at line 430 of file rtcm_framer.cc.

SetBuffer()

void RTCMFramer::SetBuffer	(	void *	buffer,
		size_t	capacity_bytes
	)

Set the buffer to use for message framing.

Postcondition

buffer must exist for the lifetime of this instance.

Parameters

buffer	The framing buffer to use. Set to nullptr to allocate a buffer internally.
capacity_bytes	The maximum framing buffer capacity (in bytes).

Definition at line 193 of file rtcm_framer.cc.

SetMessageCallback()

void point_one::rtcm::RTCMFramer::SetMessageCallback ( MessageCallback  callback )

inline

Specify a function to be called when a message is framed.

Parameters

callback

The function to be called with the message header and a pointer to the message payload.

Definition at line 110 of file rtcm_framer.h.

WarnOnError()

void point_one::rtcm::RTCMFramer::WarnOnError ( bool  enabled )

inline

Enable/disable warnings for CRC and "message too large" failures.

This is typically used when the incoming stream has multiple types of binary content (e.g., interleaved FusionEngine and RTCM messages), and the RTCM message preamble is expected to appear in the non-RTCM content occasionally.

Parameters

enabled

If true, issue warnings on errors.

Definition at line 102 of file rtcm_framer.h.

Member Data Documentation

buffer_

uint8_t* point_one::rtcm::RTCMFramer::buffer_ {nullptr}

private

Definition at line 157 of file rtcm_framer.h.

callback_

MessageCallback point_one::rtcm::RTCMFramer::callback_ = nullptr

private

Definition at line 153 of file rtcm_framer.h.

capacity_bytes_

uint32_t point_one::rtcm::RTCMFramer::capacity_bytes_ {0}

private

Definition at line 158 of file rtcm_framer.h.

current_message_size_

size_t point_one::rtcm::RTCMFramer::current_message_size_ {0}

private

Definition at line 162 of file rtcm_framer.h.

decoded_msg_count_

uint32_t point_one::rtcm::RTCMFramer::decoded_msg_count_ {0}

private

Definition at line 165 of file rtcm_framer.h.

error_count_

uint32_t point_one::rtcm::RTCMFramer::error_count_ {0}

private

Definition at line 164 of file rtcm_framer.h.

is_buffer_managed_

bool point_one::rtcm::RTCMFramer::is_buffer_managed_ = false

private

Definition at line 156 of file rtcm_framer.h.

next_byte_index_

uint32_t point_one::rtcm::RTCMFramer::next_byte_index_ {0}

private

Definition at line 161 of file rtcm_framer.h.

state_

State point_one::rtcm::RTCMFramer::state_ {State::SYNC}

private

Definition at line 160 of file rtcm_framer.h.

warn_on_error_

bool point_one::rtcm::RTCMFramer::warn_on_error_ = true

private

Definition at line 155 of file rtcm_framer.h.

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The documentation for this class was generated from the following files:

• src/point_one/rtcm/rtcm_framer.h
• src/point_one/rtcm/rtcm_framer.cc