#include <novatel_message_extractor.h>

Public Member Functions
bool	ExtractCompleteMessages (const std::string input, std::vector< NmeaSentence > &nmea_sentences, std::vector< NovatelSentence > &novatel_sentences, std::vector< BinaryMessage > &binary_messages, std::string &remaining, bool keep_nmea_container=false)
	Extracts messages from a buffer of NovAtel data. More...

void	GetGpsFixMessage (const novatel_gps_msgs::Gprmc &gprmc, const novatel_gps_msgs::Gpgga &gpgga, gps_common::GPSFixPtr gps_fix)
	Combines data receives in GPRMC and GPGGA message to produce a gps_common/GPSFixPtr ROS message. More...

double	GetMostRecentUtcTime (const std::vector< NmeaSentence > &sentences)
	Iterates through the provided messages to find the first GPGGA or GPRMC message with a valid UTC time, then returns it. More...

Private Member Functions
uint32_t	CalculateBlockCRC32 (uint32_t ulCount, const uint8_t *ucBuffer)
	Calculates the CRC-32 of a block of data all at once. More...

uint32_t	CRC32Value (int32_t i)
	Calculates the CRC-32 of a single value. More...

void	FindAsciiSentence (const std::string &sentence, size_t current_idx, size_t &start_idx, size_t &end_idx, size_t &invalid_char_idx)
	Searches for a valid ASCII message within a string. More...

int32_t	GetBinaryMessage (const std::string &str, size_t start_idx, BinaryMessage &msg)
	Extracts a binary message from a data buffer. More...

int32_t	GetNmeaSentence (const std::string &str, size_t start_idx, std::string &sentence, bool keep_container=false)
	Extracts an NMEA sentence from an input string. More...

bool	GetNovatelMessageParts (const std::string &sentence, std::string &message_id, std::vector< std::string > &header, std::vector< std::string > &body)
	Splits an ASCII NovAtel message up into header and body parts. More...

int32_t	GetNovatelSentence (const std::string &str, size_t start_idx, std::string &sentence)
	Extracts a NovAtel sentence from an input string. More...

size_t	GetSentenceChecksumStart (const std::string &str, size_t start_idx)
	Finds the location of the next checksum in a valid ASCII sentence. More...

uint8_t	NmeaChecksum (const std::string &sentence)
	Calculates the checksum of a NMEA sentence. More...

void	VectorizeNmeaSentence (const std::string &sentence, NmeaSentence &vectorized_message)
	Takes a sentence extracted by GetNmeaSentence and converts it into a data structure. More...

bool	VectorizeNovatelSentence (const std::string &data, NovatelSentence &sentence)
	Takes a sentence extracted by GetNovatelSentence and converts it into a data structure. More...

void	VectorizeString (const std::string &str, std::vector< std::string > &vectorized_message, const std::string &delimiters)

Static Private Attributes
static const std::string	CHECKSUM_FLAG = "*"
	Precedes checkums in ASCII messages. More...

static const std::string	FIELD_SEPARATOR = ","
	Separates data fields in ASCII messages. More...

static const std::string	HEADER_SEPARATOR = ";"
	Separates header from body in ASCII NovAtel messages. More...

static const std::string	NMEA_SENTENCE_FLAG = "$"
	Indicates the beginning of a NMEA sentence. More...

static const std::string	NOVATEL_ASCII_FLAGS = "$#"
	Used to search for both types of ASCII messages. More...

static const std::string	NOVATEL_BINARY_SYNC_BYTES = "\xAA\x44\x12"
	Indicates the beginning of a binary NovAtel message. More...

static constexpr uint32_t	NOVATEL_CRC32_POLYNOMIAL = 0xEDB88320L

static const std::string	NOVATEL_ENDLINE = "\r\n"
	Indicates the end of an ASCII message. More...

static const std::string	NOVATEL_SENTENCE_FLAG = "#"
	Indicates the beginning of an ASCII NovAtel message. More...

Detailed Description

Definition at line 58 of file novatel_message_extractor.h.

Member Function Documentation

uint32_t novatel_gps_driver::NovatelMessageExtractor::CalculateBlockCRC32	(	uint32_t	ulCount,
		const uint8_t *	ucBuffer
	)

private

Calculates the CRC-32 of a block of data all at once.

Parameters

ulCount	Number of bytes in the data block
ucBuffer	Data block

Returns: CRC-32 of the data block

Definition at line 71 of file novatel_message_extractor.cpp.

uint32_t novatel_gps_driver::NovatelMessageExtractor::CRC32Value ( int32_t i )

private

Calculates the CRC-32 of a single value.

Parameters

i	The value to process

Returns: That value's CRC-32

Definition at line 56 of file novatel_message_extractor.cpp.

bool novatel_gps_driver::NovatelMessageExtractor::ExtractCompleteMessages	(	const std::string	input,
		std::vector< NmeaSentence > &	nmea_sentences,
		std::vector< NovatelSentence > &	novatel_sentences,
		std::vector< BinaryMessage > &	binary_messages,
		std::string &	remaining,
		bool	keep_nmea_container = `false`
	)

Extracts messages from a buffer of NovAtel data.

This will search through the "input" string for any valid NMEA or NovAtel ASCII messages as well as any binary NovAtel messages, place them into the provided containers, and also provide any leftover bytes at the end of the buffer that were not part of a valid sentence.

Parameters

[in]	input	A buffer of data to search for messages
[out]	nmea_sentences	NMEA sentences found in the buffer
[out]	novatel_sentences	ASCII NovAtel sentences found in the buffer
[out]	binary_messages	Binary NovAtel message found in the buffer
[out]	remaining	Any bytes left after the last complete sentence in the buffer
[in]	keep_nmea_container	"true" to preserve message begin & end markers around parsed NMEA sentences

Returns: false if there were any errors parsing sentences

Definition at line 359 of file novatel_message_extractor.cpp.

void novatel_gps_driver::NovatelMessageExtractor::FindAsciiSentence	(	const std::string &	sentence,
		size_t	current_idx,
		size_t &	start_idx,
		size_t &	end_idx,
		size_t &	invalid_char_idx
	)

private

Searches for a valid ASCII message within a string.

What constitutes a valid ASCII message is defined by: http://docs.novatel.com/OEM7/Content/Messages/ASCII.htm

We check whether a substring: 1) Starts with '#' or '$' 2) Ends with "\r\n" 3) Between those values, only contains characters with an ASCII value of 9, 10, 11, 13, or between 32 and 126 (inclusive)

Parameters

[in]	sentence	The string to search within
[in]	current_idx	The position in the string to search from
[out]	start_idx	The position of the earliest '#' or '$', if found
[out]	end_idx	The position of the first '' after the start, if "\r\n" was found
[out]	invalid_char_idx	If an invalid character was found between the start and end, its index

Definition at line 309 of file novatel_message_extractor.cpp.

int32_t novatel_gps_driver::NovatelMessageExtractor::GetBinaryMessage	(	const std::string &	str,
		size_t	start_idx,
		BinaryMessage &	msg
	)

private

Extracts a binary message from a data buffer.

Parameters

[in]	str	The data buffer to search through.
[in]	start_idx	An index in the buffer to begin searching from.
[out]	msg	The parsed message.

Returns: >0: the number of bytes parsed into the message -1: Not enough data was available to parse the whole message -2: The message's checksum was invalid

Definition at line 144 of file novatel_message_extractor.cpp.

void novatel_gps_driver::NovatelMessageExtractor::GetGpsFixMessage	(	const novatel_gps_msgs::Gprmc &	gprmc,
		const novatel_gps_msgs::Gpgga &	gpgga,
		gps_common::GPSFixPtr	gps_fix
	)

Combines data receives in GPRMC and GPGGA message to produce a gps_common/GPSFixPtr ROS message.

Parameters

[in]	gprmc	A valid GPRMC message.
[in]	gpgga	A valid GPGGA message.
[out]	gps_fix	An initialised GPSFixPtr message must be provided; it will be filled in based on the provided GPRMC/GPGGA messages.

Definition at line 545 of file novatel_message_extractor.cpp.

double novatel_gps_driver::NovatelMessageExtractor::GetMostRecentUtcTime ( const std::vector< NmeaSentence > & sentences )

Iterates through the provided messages to find the first GPGGA or GPRMC message with a valid UTC time, then returns it.

Parameters

[in] sentences A list of NMEA sentences to search for UTC times.

Returns: The UTC time in seconds, if found; 0 if not found.

Definition at line 516 of file novatel_message_extractor.cpp.

int32_t novatel_gps_driver::NovatelMessageExtractor::GetNmeaSentence	(	const std::string &	str,
		size_t	start_idx,
		std::string &	sentence,
		bool	keep_container = `false`
	)

private

Extracts an NMEA sentence from an input string.

Parameters

[in]	str	The string to extract an NMEA sentence from.
[in]	start_idx	The index to begin searching at.
[out]	sentence	If a valid sentence was found, it will be placed here.
[out]	keep_container	"true" to keep sentence & checksum position marks in the output sentence.

Returns: 0: Success -1: Not enough data to parse a complete sentence 1: Sentence's checksum was invalid

Definition at line 256 of file novatel_message_extractor.cpp.

bool novatel_gps_driver::NovatelMessageExtractor::GetNovatelMessageParts	(	const std::string &	sentence,
		std::string &	message_id,
		std::vector< std::string > &	header,
		std::vector< std::string > &	body
	)

private

Splits an ASCII NovAtel message up into header and body parts.

Parameters

[in]	sentence	The NovAtel message to parse.
[out]	message_id	The message's ID.
[out]	header	All of the fields in the message's header.
[out]	body	All of the fields in the message's body.

Returns: false if there were errors parsing the message, true otherwise.

Definition at line 111 of file novatel_message_extractor.cpp.

int32_t novatel_gps_driver::NovatelMessageExtractor::GetNovatelSentence	(	const std::string &	str,
		size_t	start_idx,
		std::string &	sentence
	)

private

Extracts a NovAtel sentence from an input string.

Parameters

[in]	str	The string to search for a NovAtel sentence.
[in]	start_idx	The index to begin searching from.
[out]	sentence	The extracted sentence.

Returns: 0: Success -1: Not eenough data to parse a complete sentence 1: Checksum was invalid

Definition at line 210 of file novatel_message_extractor.cpp.

size_t novatel_gps_driver::NovatelMessageExtractor::GetSentenceChecksumStart	(	const std::string &	str,
		size_t	start_idx
	)

private

Finds the location of the next checksum in a valid ASCII sentence.

Parameters

str	A buffer to search for a checksum.
start_idx	The location to begin searching from.

Returns: The index of that sentence's checksum.

Definition at line 98 of file novatel_message_extractor.cpp.

uint8_t novatel_gps_driver::NovatelMessageExtractor::NmeaChecksum ( const std::string & sentence )

private

Calculates the checksum of a NMEA sentence.

Parameters

sentence The sentence to check.

Returns: That sentence's checksum.

Definition at line 87 of file novatel_message_extractor.cpp.

void novatel_gps_driver::NovatelMessageExtractor::VectorizeNmeaSentence	(	const std::string &	sentence,
		NmeaSentence &	vectorized_message
	)

private

Takes a sentence extracted by GetNmeaSentence and converts it into a data structure.

Parameters

[in]	data	A valid, extracted ASCII NMEA sentence.
[out]	sentence	A data structure containing the sentence.

Returns: false if it failed to parse the sentence, true otherwise.

Definition at line 348 of file novatel_message_extractor.cpp.

bool novatel_gps_driver::NovatelMessageExtractor::VectorizeNovatelSentence	(	const std::string &	data,
		NovatelSentence &	sentence
	)

private

Takes a sentence extracted by GetNovatelSentence and converts it into a data structure.

Parameters

[in]	data	A valid, extracted ASCII NovAtel sentence.
[out]	sentence	A data structure containing the sentence.

Returns: false if it failed to parse the sentence, true otherwise.

Definition at line 340 of file novatel_message_extractor.cpp.

void novatel_gps_driver::NovatelMessageExtractor::VectorizeString	(	const std::string &	str,
		std::vector< std::string > &	vectorized_message,
		const std::string &	delimiters
	)

private

Splits a string into a vector using any of the provided characters as delimiters.

Parameters

[in]	str	The string to parse.
[out]	vectorized_message	The split results.
[in]	delimiters	A set of characters to use as delimiters.

Definition at line 103 of file novatel_message_extractor.cpp.

Member Data Documentation

const std::string novatel_gps_driver::NovatelMessageExtractor::CHECKSUM_FLAG = "*"

staticprivate

Precedes checkums in ASCII messages.

Definition at line 111 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::FIELD_SEPARATOR = ","

staticprivate

Separates data fields in ASCII messages.

Definition at line 113 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::HEADER_SEPARATOR = ";"

staticprivate

Separates header from body in ASCII NovAtel messages.

Definition at line 115 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::NMEA_SENTENCE_FLAG = "$"

staticprivate

Indicates the beginning of a NMEA sentence.

Definition at line 117 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::NOVATEL_ASCII_FLAGS = "$#"

staticprivate

Used to search for both types of ASCII messages.

Definition at line 121 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::NOVATEL_BINARY_SYNC_BYTES = "\xAA\x44\x12"

staticprivate

Indicates the beginning of a binary NovAtel message.

Definition at line 123 of file novatel_message_extractor.h.

constexpr uint32_t novatel_gps_driver::NovatelMessageExtractor::NOVATEL_CRC32_POLYNOMIAL = 0xEDB88320L

staticprivate

Definition at line 127 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::NOVATEL_ENDLINE = "\r\n"

staticprivate

Indicates the end of an ASCII message.

Definition at line 125 of file novatel_message_extractor.h.

const std::string novatel_gps_driver::NovatelMessageExtractor::NOVATEL_SENTENCE_FLAG = "#"

staticprivate

Indicates the beginning of an ASCII NovAtel message.

Definition at line 119 of file novatel_message_extractor.h.

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

Public Member Functions

Private Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation