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