Disk ARchive 2.4.2
Public Member Functions | Protected Member Functions
libdar::sar Class Reference

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

#include <sar.hpp>

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

List of all members.

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, 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 56 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]dialogis for user interation (such a requesting a slice and pausing between slices)
[in]base_nameis the basename of all slices of the set (it will be added the ".<slice numer>.extension" to form a filename
[in]extensionis the extension of slice's filenames
[in]diris the path where to store or where are stored slices
[in]by_the_endif 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_digitsis the minimum number of digits the slices number is stored with in the filename
[in]laxif set to true will try workaround problems that would otherwise lead the operation to fail
[in]executeis 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,
const std::string &  execute = "" 
)

this constructor creates a new set of slices

Parameters:
[in,out]dialogis used for user interaction
[in]base_nameis the slice set base name
[in]extensionis the slices extension
[in]file_sizeis the size of slices (in byte)
[in]first_file_sizeis 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_overwriteif set to true, a warning will be issued before overwriting a slice
[in]x_allow_overwriteif set to false, no slice overwritting will be allowed
[in]pauseif 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]diris the path where to store the slices
[in]data_nameis a tag that has to be associated with the data.
[in]slice_permissionpermission to set for slice to be created (empty string for default behavior)
[in]slice_user_ownershipnew slices' uid (empty string for default behavior)
[in]slice_group_ownershipnew slices' gid (empty string for default behavior)
[in]x_hashdefines whether a hash file has to be generated for each slice, and wich hash algorithm to use
[in]x_min_digitsis the minimum number of digits the slices number is stored with in the filename
[in]executeis 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]awhere to put the data to read
[in]sizesays 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 160 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]awhat data to write
[in]sizeamount 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]posthe 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:
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Defines