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generic_file.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 GENERIC_FILE_HPP
#define GENERIC_FILE_HPP
#include "../my_config.h"
extern "C"
{
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
} // end extern "C"
#include "proto_generic_file.hpp"
#include "integers.hpp"
#include "crc.hpp"
#include "infinint.hpp"
#include "gf_mode.hpp"
#include <string>
namespace libdar
{
class generic_file: public proto_generic_file
{
public :
generic_file(gf_mode m) { rw = m; terminated = no_read_ahead = false; enable_crc(false); checksum = nullptr; };
generic_file(const generic_file &ref) { copy_from(ref); };
generic_file(generic_file && ref) noexcept { nullifyptr(); move_from(std::move(ref)); };
generic_file & operator = (const generic_file & ref) { destroy(); copy_from(ref); return *this; };
generic_file & operator = (generic_file && ref) noexcept { move_from(std::move(ref)); return *this; };
~generic_file() noexcept(false) { destroy(); };
void terminate();
bool operator == (generic_file & ref);
bool operator != (generic_file & ref) { return ! (*this == ref); };
gf_mode get_mode() const { return rw; };
void read_ahead(const infinint & amount);
void ignore_read_ahead(bool mode) { no_read_ahead = mode; };
virtual U_I read(char *a, U_I size) override;
virtual void write(const char *a, U_I size) override;
void write(const std::string & arg);
S_I read_back(char &a);
S_I read_forward(char &a) { if(terminated) throw SRC_BUG; return read(&a, 1); };
enum skippability { skip_backward, skip_forward };
virtual bool skippable(skippability direction, const infinint & amount) = 0;
virtual bool skip(const infinint & pos) = 0;
virtual bool skip_to_eof() = 0;
virtual bool skip_relative(S_I x) = 0;
virtual bool truncatable(const infinint & pos) const = 0;
virtual void truncate(const infinint & pos);
virtual infinint get_position() const = 0;
virtual void copy_to(generic_file &ref);
virtual void copy_to(generic_file &ref, const infinint & crc_size, crc * & value);
U_32 copy_to(generic_file &ref, U_32 size); // returns the number of byte effectively copied
infinint copy_to(generic_file &ref, infinint size); // returns the number of byte effectively copied
bool diff(generic_file & f,
const infinint & me_read_ahead,
const infinint & you_read_ahead,
const infinint & crc_size,
crc * & value);
bool diff(generic_file & f,
const infinint & me_read_ahead,
const infinint & you_read_ahead,
const infinint & crc_size,
crc * & value,
infinint & err_offset);
void reset_crc(const infinint & width);
bool crc_status() const { return active_read == &generic_file::read_crc; };
crc *get_crc();
void sync_write();
void flush_read();
protected :
void set_mode(gf_mode x) { rw = x; };
virtual void inherited_read_ahead(const infinint & amount) = 0;
virtual U_I inherited_read(char *a, U_I size) = 0;
virtual void inherited_write(const char *a, U_I size) = 0;
virtual void inherited_truncate(const infinint & pos) = 0;
virtual void inherited_sync_write() = 0;
virtual void inherited_flush_read() = 0;
virtual void inherited_terminate() = 0;
bool is_terminated() const { return terminated; };
private :
gf_mode rw;
crc *checksum;
bool terminated;
bool no_read_ahead;
U_I (generic_file::* active_read)(char *a, U_I size);
void (generic_file::* active_write)(const char *a, U_I size);
void enable_crc(bool mode);
U_I read_crc(char *a, U_I size);
void write_crc(const char *a, U_I size);
void destroy();
void nullifyptr() noexcept { checksum = nullptr; };
void copy_from(const generic_file & ref);
void move_from(generic_file && ref) noexcept;
};
} // end of namespace
#endif
libdar::crc
pure virtual class defining interface of a CRC object
Definition crc.hpp:47
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition generic_file.hpp:77
libdar::generic_file::write
virtual void write(const char *a, U_I size) override
write data to the generic_file inherited from proto_generic_file
libdar::generic_file::copy_to
infinint copy_to(generic_file &ref, infinint size)
copy the given amount to the object in argument
libdar::generic_file::truncatable
virtual bool truncatable(const infinint &pos) const =0
whether the implementation is able to truncate to the given position
libdar::generic_file::terminate
void terminate()
destructor-like call, except that it is allowed to throw exceptions
libdar::generic_file::inherited_truncate
virtual void inherited_truncate(const infinint &pos)=0
truncate file at the give offset
libdar::generic_file::inherited_sync_write
virtual void inherited_sync_write()=0
write down any pending data
libdar::generic_file::~generic_file
~generic_file() noexcept(false)
virtual destructor,
Definition generic_file.hpp:97
libdar::generic_file::skip
virtual bool skip(const infinint &pos)=0
skip at the absolute position
libdar::generic_file::generic_file
generic_file(const generic_file &ref)
copy constructor
Definition generic_file.hpp:83
libdar::generic_file::truncate
virtual void truncate(const infinint &pos)
truncate file at the given offset
libdar::generic_file::generic_file
generic_file(gf_mode m)
main constructor
Definition generic_file.hpp:80
libdar::generic_file::operator=
generic_file & operator=(const generic_file &ref)
assignment operator
Definition generic_file.hpp:89
libdar::generic_file::copy_to
virtual void copy_to(generic_file &ref)
copy all data from current position to the object in argument
libdar::generic_file::skippable
virtual bool skippable(skippability direction, const infinint &amount)=0
whether the implementation is able to skip
libdar::generic_file::copy_to
virtual void copy_to(generic_file &ref, const infinint &crc_size, crc *&value)
copy all data from the current position to the object in argument and computes a CRC value of the tra...
libdar::generic_file::crc_status
bool crc_status() const
to known whether CRC calculation is activated or not
Definition generic_file.hpp:248
libdar::generic_file::inherited_read_ahead
virtual void inherited_read_ahead(const infinint &amount)=0
tells the object that several calls to read() will follow to probably obtain at least the given amoun...
libdar::generic_file::read_back
S_I read_back(char &a)
skip back one char, read on char and skip back one char
libdar::generic_file::read_ahead
void read_ahead(const infinint &amount)
libdar::generic_file::read_forward
S_I read_forward(char &a)
read one char
Definition generic_file.hpp:140
libdar::generic_file::get_position
virtual infinint get_position() const =0
get the current read/write position
libdar::generic_file::flush_read
void flush_read()
be ready to read at current position, reseting all pending data for reading, cached and in compressio...
libdar::generic_file::skip_relative
virtual bool skip_relative(S_I x)=0
skip relatively to the current position
libdar::generic_file::operator==
bool operator==(generic_file &ref)
libdar::generic_file::skip_to_eof
virtual bool skip_to_eof()=0
skip to the end of file
libdar::generic_file::inherited_write
virtual void inherited_write(const char *a, U_I size)=0
implementation of the write() operation
libdar::generic_file::inherited_read
virtual U_I inherited_read(char *a, U_I size)=0
implementation of read() operation
libdar::generic_file::diff
bool diff(generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value, infinint &err_offset)
libdar::generic_file::diff
bool diff(generic_file &f, const infinint &me_read_ahead, const infinint &you_read_ahead, const infinint &crc_size, crc *&value)
compares the contents with the object in argument
libdar::generic_file::generic_file
generic_file(generic_file &&ref) noexcept
move constructor
Definition generic_file.hpp:86
libdar::generic_file::reset_crc
void reset_crc(const infinint &width)
reset CRC on read or writen data
libdar::generic_file::ignore_read_ahead
void ignore_read_ahead(bool mode)
Definition generic_file.hpp:123
libdar::generic_file::is_terminated
bool is_terminated() const
Definition generic_file.hpp:327
libdar::generic_file::get_mode
gf_mode get_mode() const
retreive the openning mode for this object
Definition generic_file.hpp:109
libdar::generic_file::inherited_terminate
virtual void inherited_terminate()=0
destructor-like call, except that it is allowed to throw exceptions
libdar::generic_file::write
void write(const std::string &arg)
write a string to the generic_file
libdar::generic_file::get_crc
crc * get_crc()
get CRC of the transfered date since last reset
libdar::generic_file::sync_write
void sync_write()
write any pending data
libdar::generic_file::read
virtual U_I read(char *a, U_I size) override
read data from the generic_file inherited from proto_generic_file
libdar::generic_file::copy_to
U_32 copy_to(generic_file &ref, U_32 size)
small copy (up to 4GB) with CRC calculation
libdar::generic_file::inherited_flush_read
virtual void inherited_flush_read()=0
reset internal engine, flush caches in order to read the data at current position
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
crc.hpp
class crc definition, used to handle Cyclic Redundancy Checks
gf_mode.hpp
generic modes to open file
libdar::gf_mode
gf_mode
generic_file openning modes
Definition gf_mode.hpp:44
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
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