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src/libdar/generic_file.hpp
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1/*********************************************************************/
2// dar - disk archive - a backup/restoration program
3// Copyright (C) 2002-2026 Denis Corbin
4//
5// This program is free software; you can redistribute it and/or
6// modify it under the terms of the GNU General Public License
7// as published by the Free Software Foundation; either version 2
8// of the License, or (at your option) any later version.
9//
10// This program is distributed in the hope that it will be useful,
11// but WITHOUT ANY WARRANTY; without even the implied warranty of
12// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13// GNU General Public License for more details.
14//
15// You should have received a copy of the GNU General Public License
16// along with this program; if not, write to the Free Software
17// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18//
19// to contact the author, see the AUTHOR file
20/*********************************************************************/
21
36
37#ifndef GENERIC_FILE_HPP
38#define GENERIC_FILE_HPP
39
40#include "../my_config.h"
41
42 extern "C"
43{
44#if HAVE_UNISTD_H
45#include <unistd.h>
46#endif
47} // end extern "C"
48
49#include "proto_generic_file.hpp"
50#include "integers.hpp"
51#include "crc.hpp"
52#include "infinint.hpp"
53#include "gf_mode.hpp"
54
55#include <string>
56
57 namespace libdar
58{
59
62
64
76 class generic_file: public proto_generic_file
77 {
78 public :
80 generic_file(gf_mode m) { rw = m; terminated = no_read_ahead = false; enable_crc(false); checksum = nullptr; };
81
83 generic_file(const generic_file &ref) { copy_from(ref); };
84
86 generic_file(generic_file && ref) noexcept { nullifyptr(); move_from(std::move(ref)); };
87
89 generic_file & operator = (const generic_file & ref) { destroy(); copy_from(ref); return *this; };
90
92 generic_file & operator = (generic_file && ref) noexcept { move_from(std::move(ref)); return *this; };
93
95
97 ~generic_file() noexcept(false) { destroy(); };
98
100 void terminate();
101
105 bool operator == (generic_file & ref);
106 bool operator != (generic_file & ref) { return ! (*this == ref); };
107
109 gf_mode get_mode() const { return rw; };
110
116 void read_ahead(const infinint & amount);
117
124 void ignore_read_ahead(bool mode) { no_read_ahead = mode; };
125
127 virtual U_I read(char *a, U_I size) override;
128
130 virtual void write(const char *a, U_I size) override;
131
133
135 void write(const std::string & arg);
136
138 S_I read_back(char &a);
139
141 S_I read_forward(char &a) { if(terminated) throw SRC_BUG; return read(&a, 1); };
142
143
144 enum skippability { skip_backward, skip_forward };
145
147
152 virtual bool skippable(skippability direction, const infinint & amount) = 0;
153
155
159 virtual bool skip(const infinint & pos) = 0;
160
162 virtual bool skip_to_eof() = 0;
163
165 virtual bool skip_relative(S_I x) = 0;
166
168
169 virtual bool truncatable(const infinint & pos) const = 0;
170
172
184 virtual void truncate(const infinint & pos);
185
187 virtual infinint get_position() const = 0;
188
190 virtual void copy_to(generic_file &ref);
191
193
198 virtual void copy_to(generic_file &ref, const infinint & crc_size, crc * & value);
199
201 U_32 copy_to(generic_file &ref, U_32 size); // returns the number of byte effectively copied
202
204 infinint copy_to(generic_file &ref, infinint size); // returns the number of byte effectively copied
205
207
218 bool diff(generic_file & f,
219 const infinint & me_read_ahead,
220 const infinint & you_read_ahead,
221 const infinint & crc_size,
222 crc * & value);
223
236 bool diff(generic_file & f,
237 const infinint & me_read_ahead,
238 const infinint & you_read_ahead,
239 const infinint & crc_size,
240 crc * & value,
241 infinint & err_offset);
242
244
246 void reset_crc(const infinint & width);
247
249 bool crc_status() const { return active_read == &generic_file::read_crc; };
250
252
256 crc *get_crc();
257
259 void sync_write();
260
262 void flush_read();
263
264
265 protected :
266 void set_mode(gf_mode x) { rw = x; };
267
269
273 virtual void inherited_read_ahead(const infinint & amount) = 0;
274
275
277
286 virtual U_I inherited_read(char *a, U_I size) = 0;
287
289
293 virtual void inherited_write(const char *a, U_I size) = 0;
294
296
301 virtual void inherited_truncate(const infinint & pos) = 0;
302
303
305
309 virtual void inherited_sync_write() = 0;
310
312
317 virtual void inherited_flush_read() = 0;
318
320
323 virtual void inherited_terminate() = 0;
324
325
328 bool is_terminated() const { return terminated; };
329
330 private :
331 gf_mode rw;
332 crc *checksum;
333 bool terminated;
334 bool no_read_ahead;
335 U_I (generic_file::* active_read)(char *a, U_I size);
336 void (generic_file::* active_write)(const char *a, U_I size);
337
338 void enable_crc(bool mode);
339
340 U_I read_crc(char *a, U_I size);
341 void write_crc(const char *a, U_I size);
342 void destroy();
343 void nullifyptr() noexcept { checksum = nullptr; };
344 void copy_from(const generic_file & ref);
345 void move_from(generic_file && ref) noexcept;
346 };
347
349
350} // end of namespace
351
352#endif
libdar::crc
pure virtual class defining interface of a CRC object
Definition dar64-2.8.3-win64/include/dar/crc.hpp:47
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition dar64-2.8.3-win64/include/dar/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 src/libdar/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 src/libdar/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 src/libdar/generic_file.hpp:80
libdar::generic_file::operator=
generic_file & operator=(const generic_file &ref)
assignment operator
Definition dar64-2.8.3-win64/include/dar/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 src/libdar/generic_file.hpp:249
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 src/libdar/generic_file.hpp:141
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 src/libdar/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 src/libdar/generic_file.hpp:124
libdar::generic_file::is_terminated
bool is_terminated() const
Definition src/libdar/generic_file.hpp:328
libdar::generic_file::get_mode
gf_mode get_mode() const
retreive the openning mode for this object
Definition src/libdar/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 dar64-2.8.3-win64/include/dar/real_infinint.hpp:62
libdar::proto_generic_file
ancestor class of generic_file
Definition dar64-2.8.3-win64/include/dar/proto_generic_file.hpp:55
libdar::gf_mode
gf_mode
generic_file openning modes
Definition dar64-2.8.3-win64/include/dar/gf_mode.hpp:44
my_config.h
include macro defined by the configure script and some specific additional ones
libdar
libdar namespace encapsulate all libdar symbols
Definition dar64-2.8.3-win64/include/dar/archive.hpp:47
crc.hpp
class crc definition, used to handle Cyclic Redundancy Checks
gf_mode.hpp
generic modes to open file
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
proto_generic_file.hpp
precursor class of generic_file used to avoid cyclic dependencies with storage and infinint