class cat_signature combines the cat_entree::signature() of the object with its saved_status and read and store this combinason More...

#include <cat_signature.hpp>

Collaboration diagram for libdar::cat_signature:

Public Member Functions
	cat_signature (unsigned char original, saved_status status)
	set a signature from running libdar

	cat_signature (generic_file &f, const archive_version &reading_ver)
	set a signature from an disk archive

bool	read (generic_file &f, const archive_version &reading_ver)
	read a signature from archive for an existing cat_signature object (overwrite its value) More...

void	write (generic_file &f)

bool	get_base_and_status (unsigned char &base, saved_status &saved) const
	provide typ and status as read from the archive More...

Static Public Member Functions
static bool	compatible_signature (unsigned char a, unsigned char b)

Private Attributes
unsigned char	field
	stores file type and status information More...

Static Private Attributes
static constexpr U_8	SAVED_FAKE_BIT = 0x80

static constexpr U_8	SAVED_NON_DELTA_BIT = 0x40

Detailed Description

class cat_signature combines the cat_entree::signature() of the object with its saved_status and read and store this combinason

historically these two fields were saved on a single byte, but as libdar received new feature it was to narrow where from this class to transparently manage this field evolution

Definition at line 48 of file cat_signature.hpp.

Member Function Documentation

◆ get_base_and_status()

bool libdar::cat_signature::get_base_and_status	(	unsigned char &	base,
		saved_status &	saved
	)		const

provide typ and status as read from the archive

Parameters

[out]	base	the signature() of the entry
[out]	saved	the get_saved_status() of the entry

Returns: false if the field read from the archive is malformed, in which case the returned argument are meaningless

◆ read()

bool libdar::cat_signature::read	(	generic_file &	f,
		const archive_version &	reading_ver
	)

read a signature from archive for an existing cat_signature object (overwrite its value)

Parameters

[in]	f	where to read data from
[in]	reading_ver	which format to expect

Returns: true if data could be read, false else.

Note: the validity of the read data is not checked at that time but a the time get_base_and_status() is called

Member Data Documentation

◆ field

unsigned char libdar::cat_signature::field

private

stores file type and status information

Note: this field "field" stores two types of information: Historically, the type was stored as different letters, then the differential backup has been added and the saved/not_saved status appeared as uppercase for not_saved status and lowercase for saved status (backward compatibility)

adding features after features, the FAKE status used in isolated catalogues used the bit 8 (ASCII used 7 lower bits only).

but while adding the delta-diff feature it has been realized that 3 bits could be used beside information type to store the status thanks to the way ASCI encodes letters: the 5 lower bits encode the letter nature, remains the bits 6, 7 and 8 to encode the status of the inode:

Definition at line 107 of file cat_signature.hpp.

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

cat_signature.hpp

Public Member Functions

Static Public Member Functions