Detailed Description

Provides a write interface to an MCAP file.

Definition at line 322 of file writer.hpp.

#include <writer.hpp>

Public Member Functions
	~McapWriter ()

Status	open (std::string_view filename, const McapWriterOptions &options)
	Open a new MCAP file for writing and write the header.

void	open (IWritable &writer, const McapWriterOptions &options)
	Open a new MCAP file for writing and write the header.

void	open (std::ostream &stream, const McapWriterOptions &options)
	Open a new MCAP file for writing and write the header.

void	close ()
	Write the MCAP footer, flush pending writes to the output stream, and reset internal state. The writer may be re-used with another call to open afterwards.

void	terminate ()
	Reset internal state without writing the MCAP footer or flushing pending writes. This should only be used in error cases as the output MCAP file will be truncated. The writer may be re-used with another call to open afterwards.

void	addSchema (Schema &schema)
	Add a new schema to the MCAP file and set `schema.id` to a generated schema id. The schema id is used when adding channels to the file.

void	addChannel (Channel &channel)
	Add a new channel to the MCAP file and set `channel.id` to a generated channel id. The channel id is used when adding messages to the file.

Status	write (const Message &message)
	Write a message to the output stream.

Status	write (Attachment &attachment)
	Write an attachment to the output stream.

Status	write (const Metadata &metadata)
	Write a metadata record to the output stream.

const Statistics &	statistics () const
	Current MCAP file-level statistics. This is written as a Statistics record in the Summary section of the MCAP file.

IWritable *	dataSink ()
	Returns a pointer to the IWritable data destination backing this writer. Will return nullptr if the writer is not open.

void	closeLastChunk ()
	finishes the current chunk in progress and writes it to the file, if a chunk is in progress.

Static Public Member Functions
static void	writeMagic (IWritable &output)

static uint64_t	write (IWritable &output, const Header &header)

static uint64_t	write (IWritable &output, const Footer &footer, bool crcEnabled)

static uint64_t	write (IWritable &output, const Schema &schema)

static uint64_t	write (IWritable &output, const Channel &channel)

static uint64_t	getRecordSize (const Message &message)

static uint64_t	write (IWritable &output, const Message &message)

static uint64_t	write (IWritable &output, const Attachment &attachment)

static uint64_t	write (IWritable &output, const Metadata &metadata)

static uint64_t	write (IWritable &output, const Chunk &chunk)

static uint64_t	write (IWritable &output, const MessageIndex &index)

static uint64_t	write (IWritable &output, const ChunkIndex &index)

static uint64_t	write (IWritable &output, const AttachmentIndex &index)

static uint64_t	write (IWritable &output, const MetadataIndex &index)

static uint64_t	write (IWritable &output, const Statistics &stats)

static uint64_t	write (IWritable &output, const SummaryOffset &summaryOffset)

static uint64_t	write (IWritable &output, const DataEnd &dataEnd)

static uint64_t	write (IWritable &output, const Record &record)

static void	write (IWritable &output, const std::string_view str)

static void	write (IWritable &output, const ByteArray bytes)

static void	write (IWritable &output, OpCode value)

static void	write (IWritable &output, uint16_t value)

static void	write (IWritable &output, uint32_t value)

static void	write (IWritable &output, uint64_t value)

static void	write (IWritable &output, const std::byte *data, uint64_t size)

static void	write (IWritable &output, const KeyValueMap &map, uint32_t size=0)

Private Member Functions
IWritable &	getOutput ()

IChunkWriter *	getChunkWriter ()

void	writeChunk (IWritable &output, IChunkWriter &chunkData)

Private Attributes
McapWriterOptions	options_ {""}

uint64_t	chunkSize_ = DefaultChunkSize

IWritable *	output_ = nullptr

std::unique_ptr< FileWriter >	fileOutput_

std::unique_ptr< StreamWriter >	streamOutput_

std::unique_ptr< BufferWriter >	uncompressedChunk_

std::unique_ptr< LZ4Writer >	lz4Chunk_

std::unique_ptr< ZStdWriter >	zstdChunk_

std::vector< Schema >	schemas_

std::vector< Channel >	channels_

std::vector< AttachmentIndex >	attachmentIndex_

std::vector< MetadataIndex >	metadataIndex_

std::vector< ChunkIndex >	chunkIndex_

Statistics	statistics_ {}

std::unordered_set< SchemaId >	writtenSchemas_

std::unordered_map< ChannelId, MessageIndex >	currentMessageIndex_

Timestamp	currentChunkStart_ = MaxTime

Timestamp	currentChunkEnd_ = 0

Compression	compression_ = Compression::None

uint64_t	uncompressedSize_ = 0

bool	opened_ = false

Constructor & Destructor Documentation

◆ ~McapWriter()

mcap::McapWriter::~McapWriter ( )

Definition at line 302 of file writer.inl.

Member Function Documentation

◆ addChannel()

void mcap::McapWriter::addChannel ( Channel & channel )

Add a new channel to the MCAP file and set channel.id to a generated channel id. The channel id is used when adding messages to the file.

Channels are not cleared when the state is reset via close() or terminate(). If you're re-using a writer for multiple files in a row, the channels only need to be added once, before first use.

This method does not de-duplicate channels.

Parameters

channel Description of the channel to register. The id value is ignored and will be set to a generated channel id.

Definition at line 520 of file writer.inl.

◆ addSchema()

void mcap::McapWriter::addSchema ( Schema & schema )

Add a new schema to the MCAP file and set schema.id to a generated schema id. The schema id is used when adding channels to the file.

Schemas are not cleared when the state is reset via close() or terminate(). If you're re-using a writer for multiple files in a row, the schemas only need to be added once, before first use.

This method does not de-duplicate schemas.

Parameters

schema Description of the schema to register. The id field is ignored and will be set to a generated schema id.

Definition at line 515 of file writer.inl.

◆ close()

void mcap::McapWriter::close ( )

Write the MCAP footer, flush pending writes to the output stream, and reset internal state. The writer may be re-used with another call to open afterwards.

Definition at line 373 of file writer.inl.

◆ closeLastChunk()

void mcap::McapWriter::closeLastChunk ( )

finishes the current chunk in progress and writes it to the file, if a chunk is in progress.

Definition at line 362 of file writer.inl.

◆ dataSink()

IWritable * mcap::McapWriter::dataSink ( )

Returns a pointer to the IWritable data destination backing this writer. Will return nullptr if the writer is not open.

Definition at line 697 of file writer.inl.

◆ getChunkWriter()

IChunkWriter * mcap::McapWriter::getChunkWriter ( )

private

Definition at line 722 of file writer.inl.

◆ getOutput()

IWritable & mcap::McapWriter::getOutput ( )

private

Definition at line 703 of file writer.inl.

◆ getRecordSize()

uint64_t mcap::McapWriter::getRecordSize ( const Message & message )

static

Definition at line 906 of file writer.inl.

◆ open() [1/3]

void mcap::McapWriter::open	(	IWritable &	writer,
		const McapWriterOptions &	options
	)

Open a new MCAP file for writing and write the header.

If the writer was already opened, this calls close() first to reset the state. A writer may be re-used after being reset via close() or terminate().

Parameters

writer	An implementation of the IWritable interface. Output bytes will be written to this object.
options	Options for MCAP writing. `profile` is required.

Definition at line 306 of file writer.inl.

◆ open() [2/3]

void mcap::McapWriter::open	(	std::ostream &	stream,
		const McapWriterOptions &	options
	)

Open a new MCAP file for writing and write the header.

Parameters

stream	Output stream to write to.
options	Options for MCAP writing. `profile` is required.

Definition at line 355 of file writer.inl.

◆ open() [3/3]

Status mcap::McapWriter::open	(	std::string_view	filename,
		const McapWriterOptions &	options
	)

Open a new MCAP file for writing and write the header.

If the writer was already opened, this calls close() first to reset the state. A writer may be re-used after being reset via close() or terminate().

Parameters

filename	Filename of the MCAP file to write.
options	Options for MCAP writing. `profile` is required.

Returns: A non-success status if the file could not be opened for writing.

Definition at line 342 of file writer.inl.

◆ statistics()

const Statistics & mcap::McapWriter::statistics ( ) const

Current MCAP file-level statistics. This is written as a Statistics record in the Summary section of the MCAP file.

Definition at line 693 of file writer.inl.

◆ terminate()

void mcap::McapWriter::terminate ( )

Reset internal state without writing the MCAP footer or flushing pending writes. This should only be used in error cases as the output MCAP file will be truncated. The writer may be re-used with another call to open afterwards.

Definition at line 486 of file writer.inl.

◆ write() [1/27]

Status mcap::McapWriter::write ( Attachment & attachment )

Write an attachment to the output stream.

Parameters

attachment Attachment to add. The attachment.crc will be calculated and set if configuration options allow CRC calculation.

Returns: A non-zero error code on failure.

Definition at line 617 of file writer.inl.

◆ write() [2/27]

Status mcap::McapWriter::write ( const Message & message )

Write a message to the output stream.

Parameters

msg	Message to add.

Returns: A non-zero error code on failure.

Definition at line 525 of file writer.inl.

◆ write() [3/27]

Status mcap::McapWriter::write ( const Metadata & metadata )

Write a metadata record to the output stream.

Parameters

metadata Named group of key/value string pairs to add.

Returns: A non-zero error code on failure.

Definition at line 665 of file writer.inl.

◆ write() [4/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Attachment &	attachment
	)

static

Definition at line 924 of file writer.inl.

◆ write() [5/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const AttachmentIndex &	index
	)

static

Definition at line 1021 of file writer.inl.

◆ write() [6/27]

void mcap::McapWriter::write	(	IWritable &	output,
		const ByteArray	bytes
	)

static

Definition at line 1126 of file writer.inl.

◆ write() [7/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Channel &	channel
	)

static

Definition at line 887 of file writer.inl.

◆ write() [8/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Chunk &	chunk
	)

static

Definition at line 953 of file writer.inl.

◆ write() [9/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const ChunkIndex &	index
	)

static

Definition at line 988 of file writer.inl.

◆ write() [10/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const DataEnd &	dataEnd
	)

static

Definition at line 1103 of file writer.inl.

◆ write() [11/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Footer &	footer,
		bool	crcEnabled
	)

static

Definition at line 853 of file writer.inl.

◆ write() [12/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Header &	header
	)

static

Definition at line 842 of file writer.inl.

◆ write() [13/27]

void mcap::McapWriter::write	(	IWritable &	output,
		const KeyValueMap &	map,
		uint32_t	size = `0`
	)

static

Definition at line 1151 of file writer.inl.

◆ write() [14/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Message &	message
	)

static

Definition at line 910 of file writer.inl.

◆ write() [15/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const MessageIndex &	index
	)

static

Definition at line 971 of file writer.inl.

◆ write() [16/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Metadata &	metadata
	)

static

Definition at line 941 of file writer.inl.

◆ write() [17/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const MetadataIndex &	index
	)

static

Definition at line 1043 of file writer.inl.

◆ write() [18/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Record &	record
	)

static

Definition at line 1113 of file writer.inl.

◆ write() [19/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Schema &	schema
	)

static

Definition at line 871 of file writer.inl.

◆ write() [20/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const Statistics &	stats
	)

static

Definition at line 1057 of file writer.inl.

◆ write() [21/27]

void mcap::McapWriter::write	(	IWritable &	output,
		const std::byte *	data,
		uint64_t	size
	)

static

Definition at line 1147 of file writer.inl.

◆ write() [22/27]

void mcap::McapWriter::write	(	IWritable &	output,
		const std::string_view	str
	)

static

Definition at line 1121 of file writer.inl.

◆ write() [23/27]

uint64_t mcap::McapWriter::write	(	IWritable &	output,
		const SummaryOffset &	summaryOffset
	)

static

Definition at line 1089 of file writer.inl.

◆ write() [24/27]

void mcap::McapWriter::write	(	IWritable &	output,
		OpCode	value
	)

static

Definition at line 1131 of file writer.inl.

◆ write() [25/27]

void mcap::McapWriter::write	(	IWritable &	output,
		uint16_t	value
	)

static

Definition at line 1135 of file writer.inl.

◆ write() [26/27]

void mcap::McapWriter::write	(	IWritable &	output,
		uint32_t	value
	)

static

Definition at line 1139 of file writer.inl.

◆ write() [27/27]

void mcap::McapWriter::write	(	IWritable &	output,
		uint64_t	value
	)

static

Definition at line 1143 of file writer.inl.

◆ writeChunk()

void mcap::McapWriter::writeChunk	(	IWritable &	output,
		IChunkWriter &	chunkData
	)

private

Definition at line 742 of file writer.inl.

◆ writeMagic()

void mcap::McapWriter::writeMagic ( IWritable & output )

static

Definition at line 838 of file writer.inl.

Member Data Documentation

◆ attachmentIndex_

std::vector<AttachmentIndex> mcap::McapWriter::attachmentIndex_

private

Definition at line 493 of file writer.hpp.

◆ channels_

std::vector<Channel> mcap::McapWriter::channels_

private

Definition at line 492 of file writer.hpp.

◆ chunkIndex_

std::vector<ChunkIndex> mcap::McapWriter::chunkIndex_

private

Definition at line 495 of file writer.hpp.

◆ chunkSize_

uint64_t mcap::McapWriter::chunkSize_ = DefaultChunkSize

private

Definition at line 480 of file writer.hpp.

◆ compression_

Compression mcap::McapWriter::compression_ = Compression::None

private

Definition at line 501 of file writer.hpp.

◆ currentChunkEnd_

Timestamp mcap::McapWriter::currentChunkEnd_ = 0

private

Definition at line 500 of file writer.hpp.

◆ currentChunkStart_

Timestamp mcap::McapWriter::currentChunkStart_ = MaxTime

private

Definition at line 499 of file writer.hpp.

◆ currentMessageIndex_

std::unordered_map<ChannelId, MessageIndex> mcap::McapWriter::currentMessageIndex_

private

Definition at line 498 of file writer.hpp.

◆ fileOutput_

std::unique_ptr<FileWriter> mcap::McapWriter::fileOutput_

private

Definition at line 482 of file writer.hpp.

◆ lz4Chunk_

std::unique_ptr<LZ4Writer> mcap::McapWriter::lz4Chunk_

private

Definition at line 486 of file writer.hpp.

◆ metadataIndex_

std::vector<MetadataIndex> mcap::McapWriter::metadataIndex_

private

Definition at line 494 of file writer.hpp.

◆ opened_

bool mcap::McapWriter::opened_ = false

private

Definition at line 503 of file writer.hpp.

◆ options_

McapWriterOptions mcap::McapWriter::options_ {""}

private

Definition at line 479 of file writer.hpp.

◆ output_

IWritable* mcap::McapWriter::output_ = nullptr

private

Definition at line 481 of file writer.hpp.

◆ schemas_

std::vector<Schema> mcap::McapWriter::schemas_

private

Definition at line 491 of file writer.hpp.

◆ statistics_

Statistics mcap::McapWriter::statistics_ {}

private

Definition at line 496 of file writer.hpp.

◆ streamOutput_

std::unique_ptr<StreamWriter> mcap::McapWriter::streamOutput_

private

Definition at line 483 of file writer.hpp.

◆ uncompressedChunk_

std::unique_ptr<BufferWriter> mcap::McapWriter::uncompressedChunk_

private

Definition at line 484 of file writer.hpp.

◆ uncompressedSize_

uint64_t mcap::McapWriter::uncompressedSize_ = 0

private

Definition at line 502 of file writer.hpp.

◆ writtenSchemas_

std::unordered_set<SchemaId> mcap::McapWriter::writtenSchemas_

private

Definition at line 497 of file writer.hpp.

◆ zstdChunk_

std::unique_ptr<ZStdWriter> mcap::McapWriter::zstdChunk_

private

Definition at line 489 of file writer.hpp.

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

Detailed Description

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ ~McapWriter()

Member Function Documentation

◆ addChannel()

◆ addSchema()

◆ close()

◆ closeLastChunk()

◆ dataSink()

◆ getChunkWriter()

◆ getOutput()

◆ getRecordSize()

◆ open() [1/3]

◆ open() [2/3]

◆ open() [3/3]

◆ statistics()

◆ terminate()

◆ write() [1/27]

◆ write() [2/27]

◆ write() [3/27]

◆ write() [4/27]

◆ write() [5/27]

◆ write() [6/27]

◆ write() [7/27]

◆ write() [8/27]

◆ write() [9/27]

◆ write() [10/27]

◆ write() [11/27]

◆ write() [12/27]

◆ write() [13/27]

◆ write() [14/27]

◆ write() [15/27]

◆ write() [16/27]

◆ write() [17/27]

◆ write() [18/27]

◆ write() [19/27]

◆ write() [20/27]

◆ write() [21/27]

◆ write() [22/27]

◆ write() [23/27]

◆ write() [24/27]

◆ write() [25/27]

◆ write() [26/27]

◆ write() [27/27]

◆ writeChunk()

◆ writeMagic()

Member Data Documentation

◆ attachmentIndex_

◆ channels_

◆ chunkIndex_

◆ chunkSize_

◆ compression_

◆ currentChunkEnd_

◆ currentChunkStart_

◆ currentMessageIndex_

◆ fileOutput_

◆ lz4Chunk_

◆ metadataIndex_

◆ opened_

◆ options_

◆ output_

◆ schemas_

◆ statistics_

◆ streamOutput_

◆ uncompressedChunk_

◆ uncompressedSize_

◆ writtenSchemas_

◆ zstdChunk_