hash_fichier.hpp

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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2025 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 HASH_FICHIER_HPP
#define HASH_FICHIER_HPP
 
#include "../my_config.h"
 
extern "C"
{
#if HAVE_GCRYPT_H
#ifndef GCRYPT_NO_DEPRECATED
#define GCRYPT_NO_DEPRECATED
#endif
#include <gcrypt.h>
#endif
 
#if HAVE_RHASH_H
#include <rhash.h>
#endif
}
 
#include <string>
 
#include "fichier_global.hpp"
#include "integers.hpp"
#include "archive_aux.hpp"
 
namespace libdar
{
 
 
 
    class hash_fichier : public fichier_global
    {
    public:
 
 
        hash_fichier(const std::shared_ptr<user_interaction> & dialog,
             fichier_global *under,
             const std::string & under_filename,
             fichier_global *hash_file,
             hash_algo algo);
 
    hash_fichier(const hash_fichier & ref) = delete;
 
    hash_fichier(hash_fichier && ref) noexcept = delete;
 
    hash_fichier & operator = (const hash_fichier & ref) = delete;
 
    hash_fichier & operator = (hash_fichier && ref) noexcept = delete;
 
    ~hash_fichier();
 
        // inherited from fichier_global
    virtual void change_ownership(const std::string & user, const std::string & group) override { if(ref == nullptr || hash_ref == nullptr) throw SRC_BUG; ref->change_ownership(user, group); hash_ref->change_ownership(user, group); };
    virtual void change_permission(U_I perm) override { if(ref == nullptr || hash_ref == nullptr) throw SRC_BUG; ref->change_permission(perm); hash_ref->change_permission(perm); };
    virtual infinint get_size() const override { if(ref == nullptr) throw SRC_BUG; return ref->get_size(); };
    virtual void fadvise(advise adv) const override { if(ref == nullptr) throw SRC_BUG; ref->fadvise(adv); };
 
        // inherited from generic_file
    virtual bool skippable(skippability direction, const infinint & amount) override { return false; };
        virtual bool skip(const infinint & pos) override {if(ref == nullptr || pos != ref->get_position()) throw SRC_BUG; else return true; };
        virtual bool skip_to_eof() override { if(get_mode() == gf_write_only) return true; else throw SRC_BUG; };
        virtual bool skip_relative(S_I x) override { if(x != 0) throw SRC_BUG; else return true; };
    virtual bool truncatable(const infinint & pos) const override { return false; };
    virtual infinint get_position() const override { if(ref == nullptr) throw SRC_BUG; return ref->get_position(); };
 
    void set_only_hash() { only_hash = true; };
 
    protected:
        // inherited from fichier_global
    virtual void inherited_read_ahead(const infinint & amount) override { ref->read_ahead(amount); };
    virtual U_I fichier_global_inherited_write(const char *a, U_I size) override;
    virtual bool fichier_global_inherited_read(char *a, U_I size, U_I & read, std::string & message) override;
 
        // inherited from generic_file
    virtual void inherited_truncate(const infinint & pos) override { throw SRC_BUG; }; // truncate not supported on hash files
    virtual void inherited_sync_write() override {};
    virtual void inherited_flush_read() override {};
    virtual void inherited_terminate() override;
 
    private:
    fichier_global *ref;
    fichier_global *hash_ref;
    bool only_hash; 
#if CRYPTO_AVAILABLE
    gcry_md_hd_t hash_handle;
#endif
#if RHASH_AVAILABLE
    rhash rhash_ctxt;
#endif
    std::string ref_filename;
    U_I hash_gcrypt;
    bool eof;
    bool hash_dumped;
    hash_algo algor;
 
    void write_hash_in_hexa(void const* digest, U_I digest_size);
    };
 
 
} // end of namespace
 
 
#endif