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// Copyright (c) 2012-2014 Konstantin Isakov <ikm@zbackup.org> and ZBackup contributors, see CONTRIBUTORS
// Part of ZBackup. Licensed under GNU GPLv2 or later + OpenSSL, see LICENSE
#ifndef COMPRESSION_HH_INCLUDED
#define COMPRESSION_HH_INCLUDED
#include "sptr.hh"
#include "ex.hh"
#include "nocopy.hh"
#include "config.hh"
namespace Compression {
DEF_EX( Ex, "Compression exception", std::exception )
DEF_EX_STR( exUnsupportedCompressionMethod, "Unsupported compression method:", Ex )
// used for encoding or decoding
class EnDecoder: NoCopy
{
protected:
EnDecoder();
public:
virtual ~EnDecoder();
// encoder can read up to size bytes from data
virtual void setInput ( const void * data, size_t size ) = 0;
// how many bytes of the last input haven't been used, yet?
virtual size_t getAvailableInput() = 0;
// encoder can write up to size bytes to output
virtual void setOutput( void * data, size_t size ) = 0;
// how many bytes of free space are remaining in the output buffer
virtual size_t getAvailableOutput() = 0;
// process some bytes
// finish: will you pass more data to the encoder via setOutput?
// NOTE You must eventually set finish to true.
// returns, whether all output bytes have been written
virtual bool process( bool finish ) = 0;
};
// compression method
class CompressionMethod
{
public:
virtual ~CompressionMethod();
// returns name of compression method
// This name is saved in the file header of the compressed file.
virtual std::string getName() const = 0;
virtual sptr< EnDecoder > createEncoder( Config const & ) const = 0;
virtual sptr< EnDecoder > createEncoder() const = 0;
virtual sptr< EnDecoder > createDecoder() const = 0;
// find a compression by name
// If optional is false, it will either return a valid CompressionMethod
// object or abort the program. If optional is true, it will return
// NULL, if it cannot find the a compression with that name.
static const_sptr< CompressionMethod > findCompression(
const std::string & name, bool optional = false );
static const_sptr< CompressionMethod > selectedCompression;
static const_sptr< CompressionMethod > const compressions[];
class iterator
{
friend class CompressionMethod;
const const_sptr< CompressionMethod > * ptr;
iterator( const const_sptr< CompressionMethod > * ptr );
public:
iterator( const iterator & it );
iterator & operator =( const iterator & it );
bool operator == ( const iterator & other ) const;
bool operator != ( const iterator & other ) const;
bool atEnd() const;
iterator & operator ++();
const_sptr< CompressionMethod > operator * ();
};
static iterator begin();
static iterator end();
};
}
#endif
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