tronconneuse.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 TRONCONNEUSE_HPP
#define TRONCONNEUSE_HPP

#include "../my_config.h"
#include <string>

#include "infinint.hpp"
#include "archive_version.hpp"
#include "crypto_module.hpp"
#include "proto_tronco.hpp"

namespace libdar
{




    class tronconneuse : public proto_tronco
    {
    public:

    tronconneuse(U_32 block_size,
             generic_file & encrypted_side,
             const archive_version & reading_ver,
             std::unique_ptr<crypto_module> & ptr);

    tronconneuse(const tronconneuse & ref) : proto_tronco(ref) { copy_from(ref); };

    tronconneuse(tronconneuse && ref) noexcept: proto_tronco(std::move(ref)) { nullifyptr(); move_from(std::move(ref)); };

    tronconneuse & operator = (const tronconneuse & ref) { detruit(); proto_tronco::operator = (ref); copy_from(ref); return *this; };

    tronconneuse & operator = (tronconneuse && ref) noexcept { proto_tronco::operator = (std::move(ref)); move_from(std::move(ref)); return *this; };

    virtual ~tronconneuse() noexcept override { detruit(); }; // must not write pure virtual method from here, directly or not

    virtual bool skippable(skippability direction, const infinint & amount) override;
    virtual bool skip(const infinint & pos) override;
    virtual bool skip_to_eof() override;
    virtual bool skip_relative(S_I x) override;
    virtual bool truncatable(const infinint & pos) const override { return false; };
    virtual infinint get_position() const override { if(is_terminated()) throw SRC_BUG; return current_position; };


    virtual void write_end_of_file() override { if(is_terminated()) throw SRC_BUG; flush(); weof = true; };



    virtual void set_initial_shift(const infinint & x) override { initial_shift = x; };

    virtual void set_callback_trailing_clear_data(trailing_clear_data_callback callback) override { trailing_clear_data = callback; };

    virtual U_32 get_clear_block_size() const override { return clear_block_size; };

    private:


    virtual void inherited_read_ahead(const infinint & amount) override;

    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 { throw SRC_BUG; }; // no skippability in write mode, so no truncate possibility neither

    virtual void inherited_sync_write() override { flush(); };


    virtual void inherited_flush_read() override { buf_byte_data = 0; };

    virtual void inherited_terminate() override { flush(); };

    protected:
    const archive_version & get_reading_version() const { return reading_ver; };


    private:
    infinint initial_shift;    
        //
    infinint buf_offset;       
    U_32 buf_byte_data;        
    U_32 buf_size;             
    char *buf;                 
        //
    U_32 clear_block_size;     
    infinint current_position; 
    infinint block_num;        
    generic_file *encrypted;   
        //
    U_32 encrypted_buf_size;   
    U_32 encrypted_buf_data;   
    char *encrypted_buf;       
        //
    infinint extra_buf_offset; 
    U_32 extra_buf_size;       
    U_32 extra_buf_data;       
    char *extra_buf;           
        //
    bool weof;                 
    bool reof;                 
    archive_version reading_ver; 
    std::unique_ptr<crypto_module> crypto; 
    trailing_clear_data_callback trailing_clear_data; 


    void nullifyptr() noexcept;
    void detruit() noexcept;
    void copy_from(const tronconneuse & ref);
    void move_from(tronconneuse && ref) noexcept;
    U_32 fill_buf();       
    void flush();          
    void init_buf();       



    void position_clear2crypt(const infinint & pos,
                  infinint & file_buf_start,
                  infinint & clear_buf_start,
                  infinint & pos_in_buf,
                  infinint & block_num);

    void position_crypt2clear(const infinint & pos, infinint & clear_pos);

    bool check_current_position() { return fill_buf() < buf_byte_data; };

    void remove_trailing_clear_data_from_encrypted_buf(const infinint & crypt_offset);

    };


} // end of namespace

#endif