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memory_file.hpp
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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:62
libdar::storage
arbitrary large storage structure
Definition: storage.hpp:53
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:41
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition: generic_file.hpp:77
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
@ 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:47