mcap::ZStdWriter Class Reference

Detailed Description

An in-memory IChunkWriter implementation that holds data in a temporary buffer before flushing to an ZStandard-compressed buffer.

Definition at line 298 of file writer.hpp.

#include <writer.hpp>

Inheritance diagram for mcap::ZStdWriter:

Public Member Functions
	ZStdWriter (CompressionLevel compressionLevel, uint64_t chunkSize)
	~ZStdWriter () override
void	handleWrite (const std::byte *data, uint64_t size) override
void	end () override
	Called when the writer wants to close the current output Chunk. After this call, data() and size() should return the data and size of the compressed data.
uint64_t	size () const override
	Returns the size in bytes of the uncompressed data.
uint64_t	compressedSize () const override
	Returns the size in bytes of the compressed data. This will only be called after end().
bool	empty () const override
	Returns true if write() has never been called since initialization or the last call to clear().
void	handleClear () override
const std::byte *	data () const override
	Returns a pointer to the uncompressed data.
const std::byte *	compressedData () const override
	Returns a pointer to the compressed data. This will only be called after end().
void	clear ()
	Clear the internal state of the writer, discarding any input or output buffers.
void	write (const std::byte *data, uint64_t size)
	Called whenever the writer needs to write data to the output MCAP file.
uint32_t	crc ()
	Returns the CRC32 of the uncompressed data.
void	resetCrc ()
	Resets the CRC32 calculation.
virtual void	flush ()
	flushes any buffered data to the output. This is called by McapWriter after every completed chunk. Callers may also retain a reference to the writer and call flush() at their own cadence. Defaults to a no-op.

Public Attributes
bool	crcEnabled = false

Private Attributes
std::vector< std::byte >	uncompressedBuffer_
std::vector< std::byte >	compressedBuffer_
ZSTD_CCtx_s *	zstdContext_ = nullptr
uint32_t	crc_

Constructor & Destructor Documentation

ZStdWriter()

mcap::ZStdWriter::ZStdWriter	(	CompressionLevel	compressionLevel,
		uint64_t	chunkSize
	)

Definition at line 244 of file writer.inl.

~ZStdWriter()

mcap::ZStdWriter::~ZStdWriter ( )

override

Definition at line 251 of file writer.inl.

Member Function Documentation

clear()

void mcap::IChunkWriter::clear ( )

inherited

Clear the internal state of the writer, discarding any input or output buffers.

Definition at line 107 of file writer.inl.

compressedData()

const std::byte * mcap::ZStdWriter::compressedData ( ) const

overridevirtual

Returns a pointer to the compressed data. This will only be called after end().

Implements mcap::IChunkWriter.

Definition at line 295 of file writer.inl.

compressedSize()

uint64_t mcap::ZStdWriter::compressedSize ( ) const

overridevirtual

Returns the size in bytes of the compressed data. This will only be called after end().

Implements mcap::IChunkWriter.

Definition at line 278 of file writer.inl.

crc()

uint32_t mcap::IWritable::crc ( )

inherited

Returns the CRC32 of the uncompressed data.

Definition at line 28 of file writer.inl.

data()

const std::byte * mcap::ZStdWriter::data ( ) const

overridevirtual

Returns a pointer to the uncompressed data.

Implements mcap::IChunkWriter.

Definition at line 291 of file writer.inl.

empty()

bool mcap::ZStdWriter::empty ( ) const

overridevirtual

Returns true if write() has never been called since initialization or the last call to clear().

Implements mcap::IChunkWriter.

Definition at line 282 of file writer.inl.

end()

void mcap::ZStdWriter::end ( )

overridevirtual

Called when the writer wants to close the current output Chunk. After this call, data() and size() should return the data and size of the compressed data.

Implements mcap::IChunkWriter.

Definition at line 259 of file writer.inl.

flush()

virtual void mcap::IWritable::flush ( )

inlinevirtualinherited

flushes any buffered data to the output. This is called by McapWriter after every completed chunk. Callers may also retain a reference to the writer and call flush() at their own cadence. Defaults to a no-op.

Reimplemented in mcap::FileWriter, and mcap::StreamWriter.

Definition at line 153 of file writer.hpp.

handleClear()

void mcap::ZStdWriter::handleClear ( )

overridevirtual

Implements mcap::IChunkWriter.

Definition at line 286 of file writer.inl.

handleWrite()

void mcap::ZStdWriter::handleWrite ( const std::byte *  data, uint64_t  size  )

overridevirtual

Implements mcap::IWritable.

Definition at line 255 of file writer.inl.

resetCrc()

void mcap::IWritable::resetCrc ( )

inherited

Resets the CRC32 calculation.

Definition at line 36 of file writer.inl.

size()

uint64_t mcap::ZStdWriter::size ( ) const

overridevirtual

Returns the size in bytes of the uncompressed data.

Implements mcap::IChunkWriter.

Definition at line 274 of file writer.inl.

write()

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

inherited

Called whenever the writer needs to write data to the output MCAP file.

Parameters

data	A pointer to the data to write.
size	Size of the data in bytes.

Definition at line 21 of file writer.inl.

Member Data Documentation

compressedBuffer_

std::vector<std::byte> mcap::ZStdWriter::compressedBuffer_

private

Definition at line 314 of file writer.hpp.

crc_

uint32_t mcap::IWritable::crc_

privateinherited

Definition at line 159 of file writer.hpp.

crcEnabled

bool mcap::IWritable::crcEnabled = false

inherited

Definition at line 116 of file writer.hpp.

uncompressedBuffer_

std::vector<std::byte> mcap::ZStdWriter::uncompressedBuffer_

private

Definition at line 313 of file writer.hpp.

zstdContext_

ZSTD_CCtx_s* mcap::ZStdWriter::zstdContext_ = nullptr

private

Definition at line 315 of file writer.hpp.

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

• writer.hpp
• writer.inl