compression class for zstd algorithms More...

#include <compressor_zstd.hpp>

Inherits libdar::proto_compressor.

Collaboration diagram for libdar::compressor_zstd:

Public Member Functions
	compressor_zstd (generic_file &compressed_side, U_I compression_level=9)

	compressor_zstd (const compressor_zstd &ref)=delete

	compressor_zstd (compressor_zstd &&ref) noexcept=delete

compressor_zstd &	operator= (const compressor_zstd &ref)=delete

compressor_zstd &	operator= (compressor_zstd &&ref) noexcept=delete

virtual compression	get_algo () const override

virtual void	suspend_compression () override

virtual void	resume_compression () override

virtual bool	is_compression_suspended () const override

virtual bool	skippable (skippability direction, const infinint &amount) override
	whether the implementation is able to skip More...

virtual bool	skip (const infinint &pos) override
	skip at the absolute position More...

virtual bool	skip_to_eof () override
	skip to the end of file

virtual bool	skip_relative (S_I x) override
	skip relatively to the current position

virtual bool	truncatable (const infinint &pos) const override
	whether the implementation is able to truncate to the given position

virtual infinint	get_position () const override
	get the current read/write position

Protected Member Functions
virtual void	inherited_read_ahead (const infinint &amount) override
	tells the object that several calls to read() will follow to probably obtain at least the given amount of data More...

virtual U_I	inherited_read (char *a, U_I size) override
	implementation of read() operation More...

virtual void	inherited_write (const char *a, U_I size) override
	implementation of the write() operation More...

virtual void	inherited_truncate (const infinint &pos) override
	truncate file at the give offset More...

virtual void	inherited_sync_write () override
	write down any pending data More...

virtual void	inherited_flush_read () override
	reset internal engine, flush caches in order to read the data at current position More...

virtual void	inherited_terminate () override
	destructor-like call, except that it is allowed to throw exceptions More...

Private Member Functions
void	reset_compr_engine ()
	reset the compression engine ready for use

void	compr_flush_write ()

void	compr_flush_read ()

void	clean_read ()

void	clean_write ()

void	clear_inbuf ()
	from zstd

void	clear_outbuf ()

void	release_mem ()

void	setup_context (U_I compression_level)

Private Attributes
generic_file *	compressed

bool	suspended

Detailed Description

compression class for zstd algorithms

Definition at line 49 of file compressor_zstd.hpp.

Member Function Documentation

◆ inherited_flush_read()

virtual void libdar::compressor_zstd::inherited_flush_read ( )

inlineoverrideprotectedvirtual

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 83 of file compressor_zstd.hpp.

◆ inherited_read()

virtual U_I libdar::compressor_zstd::inherited_read	(	char *	a,
		U_I	size
	)

overrideprotectedvirtual

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.

◆ inherited_read_ahead()

virtual void libdar::compressor_zstd::inherited_read_ahead ( const infinint & amount )

inlineoverrideprotectedvirtual

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

Parameters

[in] amount is 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.

Definition at line 78 of file compressor_zstd.hpp.

References libdar::generic_file::read_ahead().

◆ inherited_sync_write()

virtual void libdar::compressor_zstd::inherited_sync_write ( )

inlineoverrideprotectedvirtual

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 82 of file compressor_zstd.hpp.

◆ inherited_terminate()

virtual void libdar::compressor_zstd::inherited_terminate ( )

overrideprotectedvirtual

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.

◆ inherited_truncate()

virtual void libdar::compressor_zstd::inherited_truncate ( const infinint & pos )

overrideprotectedvirtual

truncate file at the give offset

Note: if pos is greater than the current file size, this call may do nothing (not even enlarging the file); this call should always fail on a read-only generic_file; implementation must throw exception if truncate is not possible for other reason than read/write access mode

Implements libdar::generic_file.

◆ inherited_write()

virtual void libdar::compressor_zstd::inherited_write	(	const char *	a,
		U_I	size
	)

overrideprotectedvirtual

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.

◆ skip()

virtual bool libdar::compressor_zstd::skip ( const infinint & pos )

inlineoverridevirtual

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 71 of file compressor_zstd.hpp.

References libdar::generic_file::skip().

◆ skippable()

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

inlineoverridevirtual

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.

Definition at line 70 of file compressor_zstd.hpp.

References libdar::generic_file::skippable().

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