Disk ARchive  2.6.8
Full featured and portable backup and archiving tool
generic_file.hpp
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2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2020 Denis Corbin
4 //
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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 
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 
115  void read_ahead(const infinint & amount);
116 
123  void ignore_read_ahead(bool mode) { no_read_ahead = mode; };
124 
126  virtual U_I read(char *a, U_I size) override;
127 
129  virtual void write(const char *a, U_I size) override;
130 
132 
134  void write(const std::string & arg);
135 
137  S_I read_back(char &a);
138 
140  S_I read_forward(char &a) { if(terminated) throw SRC_BUG; return read(&a, 1); };
141 
142 
143  enum skippability { skip_backward, skip_forward };
144 
146 
151  virtual bool skippable(skippability direction, const infinint & amount) = 0;
152 
154 
158  virtual bool skip(const infinint & pos) = 0;
159 
161  virtual bool skip_to_eof() = 0;
162 
164  virtual bool skip_relative(S_I x) = 0;
165 
167  virtual infinint get_position() const = 0;
168 
170  virtual void copy_to(generic_file &ref);
171 
173 
178  virtual void copy_to(generic_file &ref, const infinint & crc_size, crc * & value);
179 
181  U_32 copy_to(generic_file &ref, U_32 size); // returns the number of byte effectively copied
182 
184  infinint copy_to(generic_file &ref, infinint size); // returns the number of byte effectively copied
185 
187 
198  bool diff(generic_file & f,
199  const infinint & me_read_ahead,
200  const infinint & you_read_ahead,
201  const infinint & crc_size,
202  crc * & value);
203 
216  bool diff(generic_file & f,
217  const infinint & me_read_ahead,
218  const infinint & you_read_ahead,
219  const infinint & crc_size,
220  crc * & value,
221  infinint & err_offset);
222 
224 
226  void reset_crc(const infinint & width);
227 
229  bool crc_status() const { return active_read == &generic_file::read_crc; };
230 
232 
236  crc *get_crc();
237 
239  void sync_write();
240 
242  void flush_read();
243 
244 
245  protected :
246  void set_mode(gf_mode x) { rw = x; };
247 
249 
253  virtual void inherited_read_ahead(const infinint & amount) = 0;
254 
255 
257 
266  virtual U_I inherited_read(char *a, U_I size) = 0;
267 
269 
273  virtual void inherited_write(const char *a, U_I size) = 0;
274 
275 
277 
281  virtual void inherited_sync_write() = 0;
282 
284 
289  virtual void inherited_flush_read() = 0;
290 
292 
295  virtual void inherited_terminate() = 0;
296 
297 
300  bool is_terminated() const { return terminated; };
301 
302  private :
303  gf_mode rw;
304  crc *checksum;
305  bool terminated;
306  bool no_read_ahead;
307  U_I (generic_file::* active_read)(char *a, U_I size);
308  void (generic_file::* active_write)(const char *a, U_I size);
309 
310  void enable_crc(bool mode);
311 
312  U_I read_crc(char *a, U_I size);
313  void write_crc(const char *a, U_I size);
314  void destroy();
315  void nullifyptr() noexcept { checksum = nullptr; };
316  void copy_from(const generic_file & ref);
317  void move_from(generic_file && ref) noexcept;
318  };
319 
321 
322 } // end of namespace
323 
324 #endif
libdar::generic_file::inherited_write
virtual void inherited_write(const char *a, U_I size)=0
implementation of the write() operation
libdar::generic_file::get_crc
crc * get_crc()
get CRC of the transfered date since last reset
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::generic_file
generic_file(gf_mode m)
main constructor
Definition: generic_file.hpp:80
libdar::generic_file::generic_file
generic_file(generic_file &&ref) noexcept
move constructor
Definition: generic_file.hpp:86
libdar::generic_file::skip_to_eof
virtual bool skip_to_eof()=0
skip to the end of file
libdar::generic_file::~generic_file
~generic_file() noexcept(false)
virtual destructor,
Definition: generic_file.hpp:97
crc.hpp
class crc definition, used to handle Cyclic Redundancy Checks
libdar::proto_generic_file
ancestor class of generic_file
Definition: proto_generic_file.hpp:54
integers.hpp
are defined here basic integer types that tend to be portable
libdar::gf_mode
gf_mode
generic_file openning modes
Definition: gf_mode.hpp:43
infinint.hpp
switch module to limitint (32 ou 64 bits integers) or infinint
libdar::infinint
the arbitrary large positive integer class
Definition: real_infinint.hpp:61
proto_generic_file.hpp
precursor class of generic_file used to avoid cyclic dependencies with storage and infinint
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
virtual bool skip(const infinint &pos)=0
skip at the absolute position
libdar::generic_file::sync_write
void sync_write()
write any pending data
libdar::generic_file::reset_crc
void reset_crc(const infinint &width)
reset CRC on read or writen data
libdar::generic_file::generic_file
generic_file(const generic_file &ref)
copy constructor
Definition: generic_file.hpp:83
libdar::generic_file::inherited_read
virtual U_I inherited_read(char *a, U_I size)=0
implementation of read() operation
libdar::generic_file::is_terminated
bool is_terminated() const
Definition: generic_file.hpp:300
libdar::generic_file::inherited_terminate
virtual void inherited_terminate()=0
destructor-like call, except that it is allowed to throw exceptions
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::skip_relative
virtual bool skip_relative(S_I x)=0
skip relatively to the current position
libdar::generic_file::get_mode
gf_mode get_mode() const
retreive the openning mode for this object
Definition: generic_file.hpp:109
libdar::crc
pure virtual class defining interface of a CRC object
Definition: crc.hpp:46
libdar::generic_file::inherited_sync_write
virtual void inherited_sync_write()=0
write down any pending data
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::skippable
virtual bool skippable(skippability direction, const infinint &amount)=0
whether the implementation is able to skip
gf_mode.hpp
generic modes to open file
libdar::generic_file::read_ahead
void read_ahead(const infinint &amount)
libdar::generic_file::terminate
void terminate()
destructor-like call, except that it is allowed to throw exceptions
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition: generic_file.hpp:76
libdar::generic_file::operator==
bool operator==(generic_file &ref)
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::inherited_flush_read
virtual void inherited_flush_read()=0
reset internal engine, flush caches in order to read the data at current position
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::read_back
S_I read_back(char &a)
skip back one char, read on char and skip back one char
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::crc_status
bool crc_status() const
to known whether CRC calculation is activated or not
Definition: generic_file.hpp:229
libdar::generic_file::operator=
generic_file & operator=(const generic_file &ref)
assignment operator
Definition: generic_file.hpp:89
libdar::generic_file::ignore_read_ahead
void ignore_read_ahead(bool mode)
Definition: generic_file.hpp:123
libdar
libdar namespace encapsulate all libdar symbols
Definition: archive.hpp:46