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crc.hpp
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/*********************************************************************/
// dar - disk archive - a backup/restoration program
// Copyright (C) 2002-2026 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 CRC_HPP
#define CRC_HPP
#include "../my_config.h"
#include <string>
#include <list>
#include "integers.hpp"
#include "storage.hpp"
#include "infinint.hpp"
#include "proto_generic_file.hpp"
namespace libdar
{
class crc
{
public:
static constexpr U_I OLD_CRC_SIZE = 2;
crc() {};
crc(const crc & ref) = default;
crc(crc && ref) noexcept = default;
crc & operator = (const crc & ref) = default;
crc & operator = (crc && ref) noexcept = default;
virtual ~crc() = default;
virtual bool operator == (const crc & ref) const = 0;
bool operator != (const crc & ref) const { return ! (*this == ref); };
virtual void compute(const infinint & offset, const char *buffer, U_I length) = 0;
virtual void compute(const char *buffer, U_I length) = 0; // for sequential read only
virtual void clear() = 0;
virtual void dump(proto_generic_file & f) const = 0;
virtual std::string crc2str() const = 0;
virtual infinint get_size() const = 0;
virtual crc *clone() const = 0;
};
extern crc *create_crc_from_file(proto_generic_file & f, bool old = false);
extern crc *create_crc_from_size(infinint width);
class crc_i : public crc
{
public:
crc_i(const infinint & width);
crc_i(const infinint & width, proto_generic_file & f);
crc_i(const crc_i & ref) : size(ref.size), cyclic(ref.size) { copy_data_from(ref); pointer = cyclic.begin(); };
crc_i(crc_i && ref) noexcept = default;
crc_i & operator = (const crc_i & ref) { copy_from(ref); return *this; };
crc_i & operator = (crc_i && ref) noexcept = default;
~crc_i() = default;
bool operator == (const crc & ref) const override;
virtual void compute(const infinint & offset, const char *buffer, U_I length) override;
virtual void compute(const char *buffer, U_I length) override; // for sequential read only
virtual void clear() override;
virtual void dump(proto_generic_file & f) const override;
virtual std::string crc2str() const override;
virtual infinint get_size() const override { return size; };
protected:
virtual crc *clone() const override { crc *tmp = new (std::nothrow) crc_i(*this); if(tmp == nullptr) throw Ememory("crc"); return tmp; };
private:
infinint size;
storage::iterator pointer;
storage cyclic;
void copy_from(const crc_i & ref);
void copy_data_from(const crc_i & ref);
};
class crc_n : public crc
{
public:
crc_n(U_I width);
crc_n(U_I width, proto_generic_file & f);
crc_n(const crc_n & ref) { copy_from(ref); };
crc_n(crc_n && ref) noexcept = default;
crc_n & operator = (const crc_n & ref);
crc_n & operator = (crc_n && ref) noexcept = default;
~crc_n() { destroy(); };
bool operator == (const crc & ref) const override;
virtual void compute(const infinint & offset, const char *buffer, U_I length) override;
virtual void compute(const char *buffer, U_I length) override; // for sequential read only
virtual void clear() override;
virtual void dump(proto_generic_file & f) const override;
virtual std::string crc2str() const override;
virtual infinint get_size() const override { return size; };
protected:
virtual crc *clone() const override { crc *tmp = new (std::nothrow) crc_n(*this); if(tmp == nullptr) throw Ememory("crc"); return tmp; };
private:
U_I size;
unsigned char *pointer;
unsigned char *cyclic;
void alloc(U_I width);
void copy_from(const crc_n & ref);
void copy_data_from(const crc_n & ref);
void destroy();
};
} // end of namespace
#endif
libdar::Ememory
exception used when memory has been exhausted
Definition erreurs.hpp:127
libdar::crc_i::cyclic
storage cyclic
the checksum storage
Definition crc.hpp:105
libdar::crc_i::pointer
storage::iterator pointer
points to the next byte to modify
Definition crc.hpp:104
libdar::crc_i::size
infinint size
size of the checksum
Definition crc.hpp:103
libdar::crc_n::cyclic
unsigned char * cyclic
the checksum storage (non infinint mode)
Definition crc.hpp:142
libdar::crc_n::size
U_I size
size of checksum (non infinint mode)
Definition crc.hpp:140
libdar::crc_n::pointer
unsigned char * pointer
points to the next byte to modify (non infinint mode)
Definition crc.hpp:141
libdar::crc
pure virtual class defining interface of a CRC object
Definition crc.hpp:47
libdar::infinint
the arbitrary large positive integer class
Definition real_infinint.hpp:62
libdar::proto_generic_file
ancestor class of generic_file
Definition proto_generic_file.hpp:55
libdar::storage
arbitrary large storage structure
Definition storage.hpp:53
libdar::create_crc_from_file
crc * create_crc_from_file(proto_generic_file &f, bool old=false)
generate a CRC object reading it from file
libdar::create_crc_from_size
crc * create_crc_from_size(infinint width)
generate a CRC object with adhoc width based on a file size
infinint.hpp
switch module to limitint (32 ou 64 bits integers) or infinint
integers.hpp
are defined here basic integer types that tend to be portable
my_config.h
include macro defined by the configure script and some specific additional ones
libdar
libdar namespace encapsulate all libdar symbols
Definition archive.hpp:47
proto_generic_file.hpp
precursor class of generic_file used to avoid cyclic dependencies with storage and infinint
storage.hpp
contains a class that permits arbitrary large data storage