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Public Member Functions | Protected Member Functions
libdar::tronc Class Reference

makes a segment of a generic_file appear like a real generic_file More...

#include <tronc.hpp>

Inherits libdar::generic_file.

Inherited by libdar::trontextual.

List of all members.

Public Member Functions

 tronc (generic_file *f, const infinint &offset, const infinint &size, bool own_f=false)
 constructor
 tronc (generic_file *f, const infinint &offset, const infinint &size, gf_mode mode, bool own_f=false)
 tronc (generic_file *f, const infinint &offset, bool own_f=false)
 tronc (generic_file *f, const infinint &offset, gf_mode mode, bool own_f=false)
 ~tronc ()
 destructor
void modify (const infinint &new_offset, const infinint &new_size)
 modify the tronc object to zoom on another (size limited) portion of the underlying object
void modify (const infinint &new_offset)
 modify the tronc object to zoom on another (size unlimited) portion of the underlying object
void modify ()
 modify the tronc object to become transparent and allow unrestricted access to the underlyuing object
bool skippable (skippability direction, const infinint &amount)
 inherited from generic_file
bool skip (const infinint &pos)
 inherited from generic_file
bool skip_to_eof ()
 inherited from generic_file
bool skip_relative (S_I x)
 inherited from generic_file
infinint get_position () const
 inherited from generic_file
void check_underlying_position_while_reading_or_writing (bool mode)

Protected Member Functions

void inherited_read_ahead (const infinint &amount)
 inherited from generic_file
U_I inherited_read (char *a, U_I size)
 inherited from generic_file
void inherited_write (const char *a, U_I size)
 inherited from generic_file
void inherited_sync_write ()
 write down any pending data
void inherited_flush_read ()
void inherited_terminate ()
 destructor-like call, except that it is allowed to throw exceptions

Detailed Description

makes a segment of a generic_file appear like a real generic_file

Definition at line 43 of file tronc.hpp.


Constructor & Destructor Documentation

libdar::tronc::tronc ( generic_file f,
const infinint offset,
const infinint size,
bool  own_f = false 
)

constructor

Parameters:
fis the file to take the segment from
offsetis the position of the beginning of the segment
sizeis the size of the segment
own_fis true if this object has to owns and may destroy the 'f' object at tronc's destruction time
libdar::tronc::tronc ( generic_file f,
const infinint offset,
bool  own_f = false 
)

other constructor, the end of the segment is the end of the underlying generic_file only data before offset is inaccessible


Member Function Documentation

when a tronc is used over a compressor, it becomes necessary to disable position check

Note:
by default, before each read or write, the tronc object check that the underlying object is at adhoc position in regard to where the cursor is currently in the tronc. Disabling that check let ignore possible position mismatch (which are normal when a compressor is found below) while reading or writing but keep seeking the underlying object to the requested position upon any call to tronc::skip_* familly methods.

Definition at line 92 of file tronc.hpp.

void libdar::tronc::inherited_flush_read ( ) [inline, protected, virtual]

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 103 of file tronc.hpp.

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

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 102 of file tronc.hpp.

References libdar::generic_file::sync_write().

void libdar::tronc::inherited_terminate ( ) [inline, 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.

Definition at line 104 of file tronc.hpp.

References libdar::generic_file::terminate().


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