secu_string.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 SECU_STRING_HPP
#define SECU_STRING_HPP

#include "../my_config.h"

#include <string>
#include "integers.hpp"
#include "erreurs.hpp"

namespace libdar
{




    class secu_string
    {
    public:

    static bool is_string_secured();


    secu_string(U_I storage_size = 0) { init(storage_size); };


    secu_string(const char *ptr, U_I size) { init(size); append_at(0, ptr, size); };

    secu_string(const secu_string & ref) { copy_from(ref); };

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

    secu_string & operator = (const secu_string & ref) { clean_and_destroy(); copy_from(ref); return *this; };

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

        ~secu_string() noexcept { clean_and_destroy(); };


    bool operator != (const std::string & ref) const { return ! (*this == ref); };
    bool operator != (const secu_string & ref) const { return ! (*this == ref); };
    bool operator == (const std::string &ref) const { return compare_with(ref.c_str(),(U_I)(ref.size())); };
    bool operator == (const secu_string &ref) const { return compare_with(ref.mem, *(ref.string_size)); };



    void set(int fd, U_I size);


    void append_at(U_I offset, const char *ptr, U_I size);

    void append_at(U_I offset, int fd, U_I size);

    void append(const char *ptr, U_I size) { append_at(*string_size, ptr, size); };

    void append(int fd, U_I size) { append_at(*string_size, fd, size); };

    void reduce_string_size_to(U_I pos);

    void expand_string_size_to(U_I size);


    void clear() { *string_size = 0; };


    void resize(U_I size) { clean_and_destroy(); init(size); };


    void randomize(U_I size);


    const char* c_str() const { return mem == nullptr ? throw SRC_BUG : mem; };
    char* c_str() { return mem == nullptr ? throw SRC_BUG : mem; };
    void set_size(U_I size);

    char * get_array() { return mem == nullptr ? throw SRC_BUG : mem; };


    char & operator[] (U_I index);
    char operator[](U_I index) const { return (const_cast<secu_string *>(this))->operator[](index); };

    U_I get_size() const { if(string_size == nullptr) throw SRC_BUG; return *string_size; }; // returns the size of the string

    bool empty() const { if(string_size == nullptr) throw SRC_BUG; return *string_size == 0; };

    U_I get_allocated_size() const { return *allocated_size - 1; };

    private:
    U_I *allocated_size;
    char *mem;
    U_I *string_size;

    void nullifyptr() noexcept { allocated_size = string_size = nullptr; mem = nullptr; };
    void init(U_I size);   //< to be used at creation time or after clean_and_destroy() only
    void copy_from(const secu_string & ref); //< to be used at creation time or after clean_and_destroy() only
    void move_from(secu_string && ref) noexcept { std::swap(allocated_size, ref.allocated_size); std::swap(mem, ref.mem); std::swap(string_size, ref.string_size); };
    bool compare_with(const char *ptr, U_I size) const; // return true if given sequence is the same as the one stored in "this"
    void clean_and_destroy();
    };


} // end of namespace

#endif