Disk ARchive  2.6.8
Full featured and portable backup and archiving tool
memory_file.hpp
Go to the documentation of this file.
1 /*********************************************************************/
2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2020 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 : http://dar.linux.free.fr/email.html
20 /*********************************************************************/
21 
25 
26 #ifndef MEMORY_FILE_HPP
27 #define MEMORY_FILE_HPP
28 
29 #include "generic_file.hpp"
30 #include "storage.hpp"
31 
32 namespace libdar
33 {
34 
37 
39 
40  class memory_file : public generic_file
41  {
42  public:
43 
45  memory_file() : generic_file(gf_read_write), data(0) { position = 0; };
46  memory_file(const memory_file & ref) = default;
47  memory_file(memory_file && ref) noexcept = default;
48  memory_file & operator = (const memory_file & ref) = default;
49  memory_file & operator = (memory_file && ref) noexcept = default;
50  ~memory_file() = default;
51 
52  // memory_storage specific methods
53 
54  void reset() { if(is_terminated()) throw SRC_BUG; position = 0; data = storage(0); };
55  infinint size() const { return data.size(); };
56 
57 
58  // virtual method inherited from generic_file
59  virtual bool skippable(skippability direction, const infinint & amount) override { return true; };
60  virtual bool skip(const infinint & pos) override;
61  virtual bool skip_to_eof() override;
62  virtual bool skip_relative(S_I x) override;
63  virtual infinint get_position() const override { if(is_terminated()) throw SRC_BUG; return position; };
64 
65 
66  protected:
67 
68  // virtual method inherited from generic_file
69  virtual void inherited_read_ahead(const infinint & amount) override {}; // no optimization can be done here, we rely on the OS here
70  virtual U_I inherited_read(char *a, U_I size) override;
71  virtual void inherited_write(const char *a, U_I size) override;
72  virtual void inherited_sync_write() override {};
73  virtual void inherited_flush_read() override {};
74  virtual void inherited_terminate() override {};
75 
76  private:
77  storage data;
78  infinint position;
79  };
80 
82 
83 } // end of namespace
84 
85 #endif
libdar::memory_file::inherited_flush_read
virtual void inherited_flush_read() override
reset internal engine, flush caches in order to read the data at current position
Definition: memory_file.hpp:73
libdar::memory_file::inherited_read
virtual U_I inherited_read(char *a, U_I size) override
implementation of read() operation
libdar::infinint
the arbitrary large positive integer class
Definition: real_infinint.hpp:61
libdar::storage
arbitrary large storage structure
Definition: storage.hpp:52
libdar::memory_file::inherited_terminate
virtual void inherited_terminate() override
destructor-like call, except that it is allowed to throw exceptions
Definition: memory_file.hpp:74
libdar::memory_file::skip_relative
virtual bool skip_relative(S_I x) override
skip relatively to the current position
libdar::memory_file::skippable
virtual bool skippable(skippability direction, const infinint &amount) override
whether the implementation is able to skip
Definition: memory_file.hpp:59
libdar::generic_file::is_terminated
bool is_terminated() const
Definition: generic_file.hpp:300
libdar::memory_file::inherited_sync_write
virtual void inherited_sync_write() override
write down any pending data
Definition: memory_file.hpp:72
libdar::memory_file::skip
virtual bool skip(const infinint &pos) override
skip at the absolute position
generic_file.hpp
class generic_file is defined here as well as class fichier
libdar::memory_file::get_position
virtual infinint get_position() const override
get the current read/write position
Definition: memory_file.hpp:63
libdar::memory_file
generic_file stored in memory
Definition: memory_file.hpp:40
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition: generic_file.hpp:76
libdar::memory_file::inherited_write
virtual void inherited_write(const char *a, U_I size) override
implementation of the write() operation
libdar::memory_file::memory_file
memory_file()
Constructors & Destructor.
Definition: memory_file.hpp:45
libdar::gf_read_write
read and write access
Definition: gf_mode.hpp:47
storage.hpp
contains a class that permits arbitrary large data storage
libdar::memory_file::skip_to_eof
virtual bool skip_to_eof() override
skip to the end of file
libdar::memory_file::inherited_read_ahead
virtual void inherited_read_ahead(const infinint &amount) override
tells the object that several calls to read() will follow to probably obtain at least the given amoun...
Definition: memory_file.hpp:69
libdar
libdar namespace encapsulate all libdar symbols
Definition: archive.hpp:46