Every file starts with this header, which may grow but not shrink! More...

#include <FileFormat.h>

Public Member Functions
void	init ()
	Initialize the structure's fixed values with default values for a regular VRS file.

void	init (uint32_t magic1, uint32_t magic2, uint32_t magic3, uint32_t formatVersion)
	Initialize the structure's fixed values, with configuration options.

bool	looksLikeAVRSFile () const

bool	looksLikeOurFiles (uint32_t magic1, uint32_t magic2, uint32_t magic3) const

bool	isFormatSupported () const

void	enableFrontIndexRecordSupport ()

int64_t	getEndOfUserRecordsOffset (int64_t fileSize) const

Static Public Member Functions
static void	setCreationIdOffset (uint64_t offset)

Public Attributes
uint32_t	magicHeader1 {}
	magic value #1

uint32_t	magicHeader2 {}
	magic value #2

uint64_t	creationId {}
	A timestamp, hopefully unique, to match files (future).

uint32_t	fileHeaderSize {}
	This header size, in bytes.

uint32_t	recordHeaderSize {}
	Record headers' size, in bytes (same for all).

int64_t	indexRecordOffset {}
	Index record offset in the whole file.

int64_t	descriptionRecordOffset {}
	Description record offset in the whole file.

int64_t	firstUserRecordOffset {}

uint64_t	future2 {}
	For future use.

uint64_t	future3 {}
	For future use.

uint64_t	future4 {}
	For future use.

uint32_t	magicHeader3 {}
	magic value #3

uint32_t	fileFormatVersion {}
	file format version.

Detailed Description

Every file starts with this header, which may grow but not shrink!

Member Function Documentation

◆ enableFrontIndexRecordSupport()

void vrs::FileFormat::FileHeader::enableFrontIndexRecordSupport ( )

By default, the index record is written at the end of the file (original behavior), and the first user record is just after the description record. You can reserve space for the index record between the description record and the first user record, so that it is possible the read the file forward only, for streaming. But if you do that, the VRS file can only be read by a newer version of VRS, so you must bump the file version number by calling this method.

◆ getEndOfUserRecordsOffset()

int64_t vrs::FileFormat::FileHeader::getEndOfUserRecordsOffset ( int64_t fileSize ) const

Get a best guess as to where user records end. If the file has no index, this value may be inaccurate, but a sensible estimation will be returned (probably the end of the file). Only call this methods for file headers read from an actual VRS file.

Parameters

fileSize the size of the VRS file, value returned if no better estimate can be made, or when the file's index is at the start of the file (in which case it is the right answer).

Returns: The index of the first byte after the last user record.

◆ isFormatSupported()

bool vrs::FileFormat::FileHeader::isFormatSupported ( ) const

Check if the file format is supported. Might fail if the file was written by a recent version of VRS that changed the file format.

◆ looksLikeAVRSFile()

bool vrs::FileFormat::FileHeader::looksLikeAVRSFile ( ) const

Check the sanity of the file header.

Returns: True if the header looks valid for a VRS file, false otherwise.

◆ looksLikeOurFiles()

bool vrs::FileFormat::FileHeader::looksLikeOurFiles	(	uint32_t	magic1,
		uint32_t	magic2,
		uint32_t	magic3
	)		const

Check the sanity of the file header.

Returns: True if the header looks valid a header we might have created, false otherwise.

◆ setCreationIdOffset()

void vrs::FileFormat::FileHeader::setCreationIdOffset ( uint64_t offset )

static

For privacy with regard to creation time, allow for the injection of a (random) creation ID offset.

Parameters

offset Offset in nanoseconds, added to the current wall-clock time. Defaults to zero.

Member Data Documentation

◆ firstUserRecordOffset

int64_t vrs::FileFormat::FileHeader::firstUserRecordOffset {}

Offset of the first user record in the file. If 0, the first record is just after the description record (original behavior)

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

vrs/FileFormat.h
vrs/FileFormat.cpp

Public Member Functions

Static Public Member Functions

Public Attributes