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compressor.hpp
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1/*********************************************************************/
2// dar - disk archive - a backup/restoration program
3// Copyright (C) 2002-2025 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
25
26#ifndef COMPRESSOR_HPP
27#define COMPRESSOR_HPP
28
29#include "../my_config.h"
30
31#include "infinint.hpp"
32#include "integers.hpp"
33#include "wrapperlib.hpp"
34#include "proto_compressor.hpp"
35
36namespace libdar
37{
38
39
42
44 class compressor : public proto_compressor
45 {
46 public :
47 compressor(compression x_algo,
48 generic_file & compressed_side,
49 U_I compression_level = 9
50 );
53
54 compressor(const compressor & ref) = delete;
55 compressor(compressor && ref) noexcept = delete;
56 compressor & operator = (const compressor & ref) = delete;
57 compressor & operator = (compressor && ref) noexcept = delete;
58 virtual ~compressor();
59
60
61 // inherited from proto_compressor
62
63 virtual compression get_algo() const override;
64 virtual void suspend_compression() override;
65 virtual void resume_compression() override;
66 virtual bool is_compression_suspended() const override { return suspended; };
67
68
69 // inherited from generic file
70
71 virtual bool skippable(skippability direction, const infinint & amount) override { return compressed->skippable(direction, amount); };
72 virtual bool skip(const infinint & pos) override { inherited_sync_write(); inherited_flush_read(); return compressed->skip(pos); };
73 virtual bool skip_to_eof() override { inherited_sync_write(); inherited_flush_read(); return compressed->skip_to_eof(); };
74 virtual bool skip_relative(S_I x) override { inherited_sync_write(); inherited_flush_read(); return compressed->skip_relative(x); };
75 virtual bool truncatable(const infinint & pos) const override { return compressed->truncatable(pos); };
76 virtual infinint get_position() const override { if(compr != nullptr && compr->wrap.get_total_in() != 0) throw SRC_BUG; return compressed->get_position(); };
77
78 protected :
79 virtual void inherited_read_ahead(const infinint & amount) override { compressed->read_ahead(amount); };
80 virtual U_I inherited_read(char *a, U_I size) override;
81 virtual void inherited_write(const char *a, U_I size) override;
82 virtual void inherited_truncate(const infinint & pos) override;
83 virtual void inherited_sync_write() override;
84 virtual void inherited_flush_read() override;
85 virtual void inherited_terminate() override;
86
87 private :
88 struct xfer
89 {
90 wrapperlib wrap;
91 char *buffer;
92 U_I size;
93
94 xfer(U_I sz, wrapperlib_mode mode);
95 ~xfer();
96 };
97
98 xfer *compr;
99 bool read_mode;
100 generic_file *compressed;
101 compression algo;
102 bool suspended;
103
104 void flush_write();
105 };
106
108
109} // end of namespace
110
111#endif
libdar::compressor
compression class for gzip and bzip2 algorithms
Definition compressor.hpp:45
libdar::compressor::algo
compression algo
compression algorithm used
Definition compressor.hpp:101
libdar::compressor::flush_write
void flush_write()
drop all pending write and reset compression engine
libdar::compressor::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 compressor.hpp:79
libdar::compressor::compressed
generic_file * compressed
where to read from/write to compressed data
Definition compressor.hpp:100
libdar::compressor::suspended
bool suspended
whether compression is temporary suspended
Definition compressor.hpp:102
libdar::compressor::inherited_sync_write
virtual void inherited_sync_write() override
write down any pending data
libdar::compressor::read_mode
bool read_mode
read-only mode or write-only mode, read-write is write-only mode
Definition compressor.hpp:99
libdar::compressor::compressor
compressor(const compressor &ref)=delete
libdar::compressor::inherited_truncate
virtual void inherited_truncate(const infinint &pos) override
truncate file at the give offset
libdar::compressor::get_position
virtual infinint get_position() const override
get the current read/write position
Definition compressor.hpp:76
libdar::compressor::skippable
virtual bool skippable(skippability direction, const infinint &amount) override
whether the implementation is able to skip
Definition compressor.hpp:71
libdar::compressor::inherited_write
virtual void inherited_write(const char *a, U_I size) override
implementation of the write() operation
libdar::compressor::skip_to_eof
virtual bool skip_to_eof() override
skip to the end of file
Definition compressor.hpp:73
libdar::compressor::inherited_terminate
virtual void inherited_terminate() override
destructor-like call, except that it is allowed to throw exceptions
libdar::compressor::skip
virtual bool skip(const infinint &pos) override
skip at the absolute position
Definition compressor.hpp:72
libdar::compressor::compressor
compressor(compression x_algo, generic_file &compressed_side, U_I compression_level=9)
libdar::compressor::truncatable
virtual bool truncatable(const infinint &pos) const override
whether the implementation is able to truncate to the given position
Definition compressor.hpp:75
libdar::compressor::inherited_flush_read
virtual void inherited_flush_read() override
reset internal engine, flush caches in order to read the data at current position
libdar::compressor::inherited_read
virtual U_I inherited_read(char *a, U_I size) override
implementation of read() operation
libdar::compressor::skip_relative
virtual bool skip_relative(S_I x) override
skip relatively to the current position
Definition compressor.hpp:74
libdar::compressor::compr
xfer * compr
datastructure for bzip2, gzip and zx compression (not use with compression::none
Definition compressor.hpp:98
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition generic_file.hpp:77
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::skip
virtual bool skip(const infinint &pos)=0
skip at the absolute position
libdar::generic_file::skippable
virtual bool skippable(skippability direction, const infinint &amount)=0
whether the implementation is able to skip
libdar::generic_file::read_ahead
void read_ahead(const infinint &amount)
libdar::generic_file::get_position
virtual infinint get_position() const =0
get the current read/write position
libdar::generic_file::skip_relative
virtual bool skip_relative(S_I x)=0
skip relatively to the current position
libdar::generic_file::skip_to_eof
virtual bool skip_to_eof()=0
skip to the end of file
libdar::infinint
the arbitrary large positive integer class
Definition real_infinint.hpp:62
libdar::wrapperlib
this class encapsulates calls to libz or libbz2
Definition wrapperlib.hpp:75
libdar::compression
compression
the different compression algorithm available
Definition compression.hpp:46
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
my_config.h
include macro defined by the configure script and some specific additional ones
libdar
libdar namespace encapsulate all libdar symbols
Definition archive.hpp:47
proto_compressor.hpp
abstracted ancestor class for compressor and parallel_compressor classes
wrapperlib.hpp
libz and libbz2 wrapper to have identical interface to these libraries.