the null_file class implements the /dev/null behavior More...

#include <null_file.hpp>

Inherits libdar::generic_file, and libdar::thread_cancellation.

Public Member Functions
	null_file (gf_mode m)
bool	skip (const infinint &pos)
	skip at the absolute position
bool	skip_to_eof ()
	skip to the end of file
bool	skip_relative (signed int x)
infinint	get_position ()
	get the current read/write position
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

the null_file class implements the /dev/null behavior

this is a generic_file implementation that emulate the comportment of the /dev/null special file. all that is writen to is lost, and nothing can be read from it (empty file). This is a completed implementation all call are consistent.

Definition at line 50 of file null_file.hpp.

Member Function Documentation

U_I libdar::null_file::inherited_read	(	char *	a,
		U_I	size
	)		`[inline, 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.

Definition at line 63 of file null_file.hpp.

References libdar::thread_cancellation::check_self_cancellation().

void libdar::null_file::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 78 of file null_file.hpp.

void libdar::null_file::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 80 of file null_file.hpp.

void libdar::null_file::inherited_write	(	const char *	a,
		U_I	size
	)		`[inline, 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.

Definition at line 71 of file null_file.hpp.

References libdar::thread_cancellation::check_self_cancellation().

bool libdar::null_file::skip ( const infinint & pos ) [inline, 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.

Definition at line 54 of file null_file.hpp.

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

null_file.hpp

Public Member Functions

Protected Member Functions

Detailed Description

Member Function Documentation