Sequentially appends BagRecord entries to a bag file. More...

#include <bag.hpp>

Public Member Functions
	BagWriter (const std::filesystem::path &path, bool enable_crc=true)
	Creates (truncating) `path` and writes the bag header.

	~BagWriter ()

	BagWriter (const BagWriter &)=delete

BagWriter &	operator= (const BagWriter &)=delete

void	write (int64_t timestamp_ns, const std::string &topic, const std::vector< std::string > &parts)
	Appends one record.

void	close ()
	Finalizes the file: writes the index/footer/trailer and flushes.

size_t	record_count () const
	Number of records written so far.

bool	crc_enabled () const

Detailed Description

Sequentially appends BagRecord entries to a bag file.

Writes the header immediately (constructor), then one record per write() call, and the trailing index + footer on close() (also invoked by the destructor if the caller never calls it explicitly). A file whose writing process is killed before close() ever runs is still a valid, readable bag – just without the O(1) index, handled by BagReader's linear-scan fallback.

Definition at line 126 of file bag.hpp.

Constructor & Destructor Documentation

◆ BagWriter() [1/2]

Mads::BagWriter::BagWriter	(	const std::filesystem::path &	path,
		bool	enable_crc = `true`
	)

explicit

Creates (truncating) path and writes the bag header.

Parameters

path	Destination file path.
enable_crc	Whether to append a CRC32 to every record (default true, per the P3 spec's "enabled by default").

Exceptions

BagError if the file cannot be created for writing.

◆ ~BagWriter()

Mads::BagWriter::~BagWriter ( )

◆ BagWriter() [2/2]

Mads::BagWriter::BagWriter ( const BagWriter & )

delete

Member Function Documentation

◆ close()

void Mads::BagWriter::close ( )

Finalizes the file: writes the index/footer/trailer and flushes.

Idempotent – a second call (or the destructor, after an explicit call) is a no-op. Not calling this at all (process killed, or a test deliberately simulating that) leaves a valid bag with only the records written so far; BagReader recovers it via linear scan.

◆ crc_enabled()

bool Mads::BagWriter::crc_enabled ( ) const

inline

Definition at line 169 of file bag.hpp.

◆ operator=()

BagWriter & Mads::BagWriter::operator= ( const BagWriter & )

delete

◆ record_count()

size_t Mads::BagWriter::record_count ( ) const

inline

Number of records written so far.

Definition at line 167 of file bag.hpp.

◆ write()

void Mads::BagWriter::write	(	int64_t	timestamp_ns,
		const std::string &	topic,
		const std::vector< std::string > &	parts
	)

Appends one record.