Sar class stands for Segmentation And Reassembly class. More...

#include <sar.hpp>

Inherits libdar::generic_file, libdar::contextual, and libdar::mem_ui.

Public Member Functions
	sar (user_interaction &dialog, const std::string &base_name, const std::string &extension, const path &dir, bool by_the_end, const infinint &x_min_digits, bool lax=false, const std::string &execute="")
	this constructor reads data from a set of slices
	sar (user_interaction &dialog, const std::string &base_name, const std::string &extension, const infinint &file_size, const infinint &first_file_size, bool x_warn_overwrite, bool x_allow_overwrite, const infinint &pause, const path &dir, const label &data_name, const std::string &slice_permission, const std::string &slice_user_ownership, const std::string &slice_group_ownership, hash_algo x_hash, const infinint &x_min_digits, bool format_07_compatible, const std::string &execute="")
	this constructor creates a new set of slices
	sar (const sar &ref)
	the destructor
	~sar ()
	destructor
bool	skip (const infinint &pos)
	skip at the absolute position
bool	skip_to_eof ()
	skip to the end of file
bool	skip_relative (S_I x)
	skip relatively to the current position
infinint	get_position ()
	get the current read/write position
infinint	get_sub_file_size () const
infinint	get_first_sub_file_size () const
bool	get_total_file_number (infinint &num) const
bool	get_last_file_size (infinint &num) const
void	disable_natural_destruction ()
void	enable_natural_destruction ()
bool	is_an_old_start_end_archive () const
const label &	get_internal_name_used () const
const label &	get_data_name () const
Protected Member Functions
U_I	inherited_read (char *a, U_I size)
	implementation of read() operation
void	inherited_write (const char *a, U_I size)
	implementation of the write() operation
void	inherited_sync_write ()
	write down any pending data
void	inherited_terminate ()
	destructor-like call, except that it is allowed to throw exceptions

Detailed Description

Sar class stands for Segmentation And Reassembly class.

sar is used as a normal file but given some parameters at construction time the object will split the data in several files of given size (aka slices) sar uses a header to identify slices in a given set and tie slices of different sets At reading time sar transparently read data from the different slices.

Definition at line 52 of file sar.hpp.

Constructor & Destructor Documentation

libdar::sar::sar	(	user_interaction &	dialog,
		const std::string &	base_name,
		const std::string &	extension,
		const path &	dir,
		bool	by_the_end,
		const infinint &	x_min_digits,
		bool	lax = `false`,
		const std::string &	execute = `""`
	)

this constructor reads data from a set of slices

Parameters:

[in]	dialog	is for user interation (such a requesting a slice and pausing between slices)
[in]	base_name	is the basename of all slices of the set (it will be added the ".<slice numer>.extension" to form a filename
[in]	extension	is the extension of slice's filenames
[in]	dir	is the path where to store or where are stored slices
[in]	by_the_end	if true dar will try to open the slice set starting from the last slice else it will try starting from the first
[in]	x_min_digits	is the minimum number of digits the slices number is stored with in the filename
[in]	lax	if set to true will try workaround problems that would otherwise lead the operation to fail
[in]	execute	is the command to execute before trying to open each slice for reading

Note:: if by_the_end is set to true, the last slice must have extended slice header that contain informations about the first slice size (used starting archive format "08"), Else, the slice size is not possible to open as the offset of the data cannot be determin. If slice header is too old the sar class will fallback openning the first slice and directly get the first slice.

libdar::sar::sar	(	user_interaction &	dialog,
		const std::string &	base_name,
		const std::string &	extension,
		const infinint &	file_size,
		const infinint &	first_file_size,
		bool	x_warn_overwrite,
		bool	x_allow_overwrite,
		const infinint &	pause,
		const path &	dir,
		const label &	data_name,
		const std::string &	slice_permission,
		const std::string &	slice_user_ownership,
		const std::string &	slice_group_ownership,
		hash_algo	x_hash,
		const infinint &	x_min_digits,
		bool	format_07_compatible,
		const std::string &	execute = `""`
	)

this constructor creates a new set of slices

Parameters:

[in,out]	dialog	is used for user interaction
[in]	base_name	is the slice set base name
[in]	extension	is the slices extension
[in]	file_size	is the size of slices (in byte)
[in]	first_file_size	is the size of the first slice (in byte) or set it to zero if it has to be equal to other slice's size
[in]	x_warn_overwrite	if set to true, a warning will be issued before overwriting a slice
[in]	x_allow_overwrite	if set to false, no slice overwritting will be allowed
[in]	pause	if set to zero no pause will be done between slice creation. If set to 1 a pause between each slice will be done. If set to N a pause each N slice will be done. Pauses must be acknoledged by user for the process to continue
[in]	dir	is the path where to store the slices
[in]	data_name	is a tag that has to be associated with the data.
[in]	slice_permission	permission to set for slice to be created (empty string for default behavior)
[in]	slice_user_ownership	new slices' uid (empty string for default behavior)
[in]	slice_group_ownership	new slices' gid (empty string for default behavior)
[in]	x_hash	defines whether a hash file has to be generated for each slice, and wich hash algorithm to use
[in]	x_min_digits	is the minimum number of digits the slices number is stored with in the filename
[in]	format_07_compatible	when set to true, creates a slice header in the archive format of version 7 instead of the highest version known
[in]	execute	is the command to execute after each slice creation (once it is completed)

Note:: if the data_name is set to "label_clear()" value, the data_name's value will be equal to the internal_name (which is the most common situation, met when creating a new archive) Specifying an explicit data_name is useful when dar_xform'ing an archive for the new archive keeps the same tag which will let it be extracted from an isolated catalogue of the original archive.

Member Function Documentation

U_I libdar::sar::inherited_read	(	char *	a,
		U_I	size
	)		`[protected, virtual]`

implementation of read() operation

Parameters:

[in,out]	a	where to put the data to read
[in]	size	says how much data to read

Returns:: the exact amount of data read and put into 'a'

Note:: read as much byte as requested, up to end of file stays blocked if not enough data is available and EOF not yet met. May return less data than requested only if EOF as been reached. in other worlds, EOF is reached when returned data is stricly less than the requested data Any problem shall be reported by throwing an exception.

Implements libdar::generic_file.

void libdar::sar::inherited_sync_write ( ) [inline, protected, virtual]

write down any pending data

Note:: this method is called after read/write mode checking from sync_write() public method;

Implements libdar::generic_file.

Definition at line 158 of file sar.hpp.

void libdar::sar::inherited_terminate ( ) [protected, virtual]

destructor-like call, except that it is allowed to throw exceptions

Note:: this method must never be called directly but using terminate() instead, generic_file class manages it to never be called more than once

Implements libdar::generic_file.

void libdar::sar::inherited_write	(	const char *	a,
		U_I	size
	)		`[protected, virtual]`

implementation of the write() operation

Parameters:

[in]	a	what data to write
[in]	size	amount of data to write

Note:: must either write all data or report an error by throwing an exception

Implements libdar::generic_file.

bool libdar::sar::skip ( const infinint & pos ) [virtual]

skip at the absolute position

Parameters:

[in] pos the offset in byte where next read/write operation must start

Returns:: true if operation was successfull and false if the requested position is not valid (after end of file)

Note:: if requested position is not valid the reading/writing cursor must be set to the closest valid position

Implements libdar::generic_file.

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

sar.hpp

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation