Disk ARchive: delta_sig_block_size.hpp Source File

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delta_sig_block_size.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 DELTA_SIG_BLOCK_SIZE_HPP
27#define DELTA_SIG_BLOCK_SIZE_HPP
28
29#include "../my_config.h"
30
31extern "C"
32{
33} // end extern "C"
34
35#include "infinint.hpp"
36
37#ifndef RS_DEFAULT_BLOCK_LEN
38#define RS_DEFAULT_BLOCK_LEN 2048
39#endif
40
41namespace libdar
42{
44
47
48
49 struct delta_sig_block_size
50 {
52 enum fs_function_t
53 {
54 fixed,
55 linear,
56 log2,
57 root2,
58 root3
59 // square2 (inexact naming) -> use root2 since release 2.8.0, same behavior just renaming
60 // square3 (inexact naming) -> use root3 since release 2.8.0, same behavior just renaming
61 };
62
63 fs_function_t fs_function;
64 infinint multiplier;
65 infinint divisor;
66 U_I min_block_len;
67 U_I max_block_len;
68
69 // definitions to help using the struct
70
71 delta_sig_block_size() { reset(); };
72 delta_sig_block_size(const delta_sig_block_size & ref) = default;
73 delta_sig_block_size(delta_sig_block_size && ref) noexcept = default;
74 delta_sig_block_size & operator = (const delta_sig_block_size & ref) = default;
75 delta_sig_block_size & operator = (delta_sig_block_size && ref) noexcept = default;
76 ~delta_sig_block_size() = default;
77
78 bool operator == (const delta_sig_block_size & ref) const;
79
81 void reset();
82
84 bool equals_default() { return (*this) == delta_sig_block_size(); };
85
87 void check() const;
88
90
93 U_I calculate(const infinint & filesize) const;
94
95 };
96
97
98} // end of namespace
99
100#endif
libdar::infinint
the arbitrary large positive integer class
Definition real_infinint.hpp:62
infinint.hpp
switch module to limitint (32 ou 64 bits integers) or infinint
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
libdar::delta_sig_block_size::multiplier
infinint multiplier
function dependently used multiplier
Definition delta_sig_block_size.hpp:64
libdar::delta_sig_block_size::min_block_len
U_I min_block_len
calculated block len will never be lower than that
Definition delta_sig_block_size.hpp:66
libdar::delta_sig_block_size::fs_function
fs_function_t fs_function
the function to use to calculate the signature block len
Definition delta_sig_block_size.hpp:63
libdar::delta_sig_block_size::check
void check() const
check the sanity of the provided values
libdar::delta_sig_block_size::fs_function_t
fs_function_t
defines the function to use to derivate block size from file size
Definition delta_sig_block_size.hpp:53
libdar::delta_sig_block_size::root2
@ root2
block size is proportional to the square root of file size
Definition delta_sig_block_size.hpp:57
libdar::delta_sig_block_size::root3
@ root3
block size if proportional to the cube root of the file size
Definition delta_sig_block_size.hpp:58
libdar::delta_sig_block_size::log2
@ log2
block size is proportional to log2(file size)
Definition delta_sig_block_size.hpp:56
libdar::delta_sig_block_size::fixed
@ fixed
block size is independant from file size
Definition delta_sig_block_size.hpp:54
libdar::delta_sig_block_size::linear
@ linear
block size if proportionnal to file size
Definition delta_sig_block_size.hpp:55
libdar::delta_sig_block_size::delta_sig_block_size
delta_sig_block_size(const delta_sig_block_size &ref)=default
set the structure to defaults value
libdar::delta_sig_block_size::calculate
U_I calculate(const infinint &filesize) const
calculate the value of the block size given the file size
libdar::delta_sig_block_size::equals_default
bool equals_default()
whether structure has default values
Definition delta_sig_block_size.hpp:84
libdar::delta_sig_block_size::divisor
infinint divisor
function dependently used divisor
Definition delta_sig_block_size.hpp:65
libdar::delta_sig_block_size::max_block_len
U_I max_block_len
calculated block len will never be higer than that except if this field is set to zero (disabling thi...
Definition delta_sig_block_size.hpp:67
libdar::delta_sig_block_size::reset
void reset()
reset to default value