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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.

Public Member Functions

 sar (const user_interaction &dialog, const std::string &base_name, const std::string &extension, const entrepot &where, 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 More...
 
 sar (const user_interaction &dialog, gf_mode open_mode, 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 entrepot &where, const label &internal_name, const label &data_name, bool force_permission, U_I permission, 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 More...
 
 sar (const sar &ref)
 the destructor
 
 ~sar ()
 destructor
 
bool skippable (skippability direction, const infinint &amount)
 
bool skip (const infinint &pos)
 
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 () const
 get the current read/write position
 
const slice_layout & get_slicing () 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
 
const entrepotget_entrepot () const
 
const infinintget_first_slice_header_size () const
 get the first slice header
 
const infinintget_non_first_slice_header_size () const
 get the non first slice header
 
- Public Member Functions inherited from libdar::generic_file
 generic_file (gf_mode m)
 main constructor
 
 generic_file (const generic_file &ref)
 copy constructor
 
virtual ~generic_file () throw (Ebug)
 virtual destructor, this let inherited destructor to be called even from a generic_file pointer to an inherited class
 
void terminate () const
 destructor-like call, except that it is allowed to throw exceptions
 
const generic_fileoperator= (const generic_file &ref)
 assignment operator
 
gf_mode get_mode () const
 retreive the openning mode for this object
 
virtual void read_ahead (const infinint &amount)
 
void ignore_read_ahead (bool mode)
 
U_I read (char *a, U_I size)
 read data from the generic_file More...
 
void write (const char *a, U_I size)
 write data to the generic_file More...
 
void write (const std::string &arg)
 write a string to the generic_file More...
 
S_I read_back (char &a)
 skip back one char, read on char and skip back one char
 
S_I read_forward (char &a)
 read one char
 
virtual void copy_to (generic_file &ref)
 copy all data from current position to the object in argument
 
virtual void copy_to (generic_file &ref, const infinint &crc_size, crc *&value)
 copy all data from the current position to the object in argument and computes a CRC value of the transmitted data More...
 
U_32 copy_to (generic_file &ref, U_32 size)
 small copy (up to 4GB) with CRC calculation
 
infinint copy_to (generic_file &ref, infinint size)
 copy the given amount to the object in argument
 
bool diff (generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value)
 compares the contents with the object in argument More...
 
bool diff (generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value, infinint &err_offset)
 
void reset_crc (const infinint &width)
 reset CRC on read or writen data More...
 
bool crc_status () const
 to known whether CRC calculation is activated or not
 
crc * get_crc ()
 get CRC of the transfered date since last reset More...
 
void sync_write ()
 write any pending data
 
void flush_read ()
 be ready to read at current position, reseting all pending data for reading, cached and in compression engine for example
 
- Public Member Functions inherited from libdar::on_pool
void * operator new (size_t n_byte)
 
void * operator new (size_t n_byte, const std::nothrow_t &nothrow_value)
 
void * operator new[] (size_t n_byte)
 
void * operator new[] (size_t n_byte, const std::nothrow_t &nothrow_value)
 
void * operator new (size_t n_byte, memory_pool *p)
 
void * operator new[] (size_t n_byte, memory_pool *p)
 
void operator delete (void *ptr, memory_pool *p)
 this operator is called by the compiler if an exception is throw from the constructor of the allocated object
 
void operator delete[] (void *ptr, memory_pool *p)
 this operator is called by the compiler if an exception is throw from the constructor of the allocated objects
 
void operator delete (void *ptr)
 this is the usual delete operator, modified to handle allocated objects allocated on a memory pool or not
 
void operator delete[] (void *ptr)
 this is the usual delete[] operator, modified to handle allocated objects allocated on a memory pool or not
 

Protected Member Functions

void inherited_read_ahead (const infinint &amount)
 
U_I inherited_read (char *a, U_I size)
 implementation of read() operation More...
 
void inherited_write (const char *a, U_I size)
 implementation of the write() operation More...
 
void inherited_sync_write ()
 write down any pending data More...
 
void inherited_flush_read ()
 
void inherited_terminate ()
 destructor-like call, except that it is allowed to throw exceptions More...
 
- Protected Member Functions inherited from libdar::generic_file
void set_mode (gf_mode x)
 
bool is_terminated () const
 
- Protected Member Functions inherited from libdar::on_pool
memory_pool * get_pool () const
 
template<class T >
void meta_new (T *&ptr, size_t num)
 
template<class T >
void meta_delete (T *ptr)
 
- Protected Member Functions inherited from libdar::mem_ui
user_interactionget_ui () const
 get access to the user_interaction cloned object More...
 
 mem_ui (const user_interaction &dialog)
 constructor More...
 
 mem_ui (user_interaction *dialog)
 
 mem_ui (const mem_ui &ref)
 the copy constructor More...
 
virtual ~mem_ui () throw (Ebug)
 destructor More...
 
const mem_uioperator= (const mem_ui &ref)
 assignement operator More...
 

Additional Inherited Members

- Public Types inherited from libdar::generic_file
enum  skippability { skip_backward, skip_forward }
 

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 54 of file sar.hpp.

Constructor & Destructor Documentation

libdar::sar::sar ( const user_interaction dialog,
const std::string &  base_name,
const std::string &  extension,
const entrepot where,
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]wheredefines 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 ( const user_interaction dialog,
gf_mode  open_mode,
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 entrepot where,
const label &  internal_name,
const label &  data_name,
bool  force_permission,
U_I  permission,
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]dialogis used for user interaction
[in]open_moderead_write or write_only is accepted only
[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]wheredefines where to store the slices
[in]internal_nameis a tag common to all slice of the archive
[in]data_nameis a tag that has to be associated with the data.
[in]force_permissionif true slice permission will be forced to the value given in the next argument
[in]permissionvalue to use to set permission of slices
[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]format_07_compatiblewhen set to true, creates a slice header in the archive format of version 7 instead of the highest version known
[in]executeis the command to execute after each slice creation (once it is completed)
Note
data_name should be equal to internal_name except when reslicing an archive as dar_xform does in which case internal_name is randomly, and data_name is kept from the source archive

Member Function Documentation

void libdar::sar::inherited_flush_read ( )
inlineprotectedvirtual

reset internal engine, flush caches in order to read the data at current position

Note
when the object relies on external object or system object to fetch the data from for reading, when a call to (inherited_)flush_read() occurs, the current object must not assume that any previously read data is still valid if it has internal buffers or the like and it should flush them asap. This call must not propagate the flush_read to any other gneric_file object it could rely on

Implements libdar::generic_file.

Definition at line 170 of file sar.hpp.

U_I libdar::sar::inherited_read ( char *  a,
U_I  size 
)
protectedvirtual

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_read_ahead ( const infinint amount)
protectedvirtual

tells the object that several calls to read() will follow to probably obtain at least the given amount of data

Parameters
[in]amountis the maximum expected amount of data that is known to be read
Note
this call may be implemented as a do-nothing call, its presence is only to allow optimization when possible, like in multi-threaded environment

Implements libdar::generic_file.

void libdar::sar::inherited_sync_write ( )
inlineprotectedvirtual

write down any pending data

Note
called after sanity checks from generic_file::sync_write() this method's role is to write down any data pending for writing in the current object it has not to be propagated to other gneric_file object this object could rely on

Implements libdar::generic_file.

Definition at line 169 of file sar.hpp.

void libdar::sar::inherited_terminate ( )
protectedvirtual

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 
)
protectedvirtual

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.

bool libdar::sar::skippable ( skippability  direction,
const infinint amount 
)
virtual

whether the implementation is able to skip

Note
the capability to skip does not mean that skip_relative() or skip() will succeed, but rather that the inherited class implementation does not by construction forbid the requested skip (like inherited class providing a generic_file interface of an anonymous pipe for example)

Implements libdar::generic_file.


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