compressor.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2024 Denis Corbin
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// to contact the author, see the AUTHOR file
/*********************************************************************/


#ifndef COMPRESSOR_HPP
#define COMPRESSOR_HPP

#include "../my_config.h"

#include "infinint.hpp"
#include "integers.hpp"
#include "wrapperlib.hpp"
#include "proto_compressor.hpp"

namespace libdar
{



    class compressor : public proto_compressor
    {
    public :
        compressor(compression x_algo,              
           generic_file & compressed_side,  
           U_I compression_level = 9        
        );

    compressor(const compressor & ref) = delete;
    compressor(compressor && ref) noexcept = delete;
    compressor & operator = (const compressor & ref) = delete;
    compressor & operator = (compressor && ref) noexcept = delete;
        virtual ~compressor();


        // inherited from proto_compressor

        virtual compression get_algo() const override;
    virtual void suspend_compression() override;
    virtual void resume_compression() override;
    virtual bool is_compression_suspended() const override { return suspended; };


            // inherited from generic file

    virtual bool skippable(skippability direction, const infinint & amount) override { return compressed->skippable(direction, amount); };
        virtual bool skip(const infinint & pos) override { inherited_sync_write(); inherited_flush_read(); return compressed->skip(pos); };
        virtual bool skip_to_eof() override { inherited_sync_write(); inherited_flush_read(); return compressed->skip_to_eof(); };
        virtual bool skip_relative(S_I x) override { inherited_sync_write(); inherited_flush_read(); return compressed->skip_relative(x); };
    virtual bool truncatable(const infinint & pos) const override { return compressed->truncatable(pos); };
        virtual infinint get_position() const override { if(compr != nullptr && compr->wrap.get_total_in() != 0) throw SRC_BUG; return compressed->get_position(); };

    protected :
    virtual void inherited_read_ahead(const infinint & amount) override { compressed->read_ahead(amount); };
        virtual U_I inherited_read(char *a, U_I size) override;
        virtual void inherited_write(const char *a, U_I size) override;
    virtual void inherited_truncate(const infinint & pos) override;
    virtual void inherited_sync_write() override;
    virtual void inherited_flush_read() override;
    virtual void inherited_terminate() override;

    private :
        struct xfer
        {
            wrapperlib wrap;
            char *buffer;
            U_I size;

            xfer(U_I sz, wrapperlib_mode mode);
            ~xfer();
        };

        xfer *compr;               
    bool read_mode;            
        generic_file *compressed;  
        compression algo;          
    bool suspended;            

    void flush_write();        
    };


} // end of namespace

#endif