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elastic.hpp
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1 /*********************************************************************/
2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2052 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 //
19 // to contact the author : http://dar.linux.free.fr/email.html
20 /*********************************************************************/
21 
25 
26 #ifndef ELASTIC_HPP
27 #define ELASTIC_HPP
28 
29 #include "../my_config.h"
30 
31 #include "integers.hpp"
32 #include "erreurs.hpp"
33 #include "infinint.hpp"
34 #include "generic_file.hpp"
35 #include "header_version.hpp"
36 
37 
38 namespace libdar
39 {
40 
43 
44 
45  enum elastic_direction { elastic_forward, elastic_backward };
46 
48 
53  class elastic
54  {
55  public:
56  elastic(U_32 size);
57  elastic(const unsigned char *buffer, U_32 size, elastic_direction dir, const archive_version & reading_ver);
58  elastic(generic_file &f, elastic_direction dir, const archive_version & reading_ver);
59 
60  U_32 dump(unsigned char *buffer, U_32 size) const;
61  U_32 get_size() const { return taille; };
62 
63  static U_I max_length() { return (U_I)(254)*254*254*254 - 1; };
64 
65 #ifdef LIBDAR_SPECIAL_ALLOC
66  USE_SPECIAL_ALLOC(elastic);
67 #endif
68 
69  private:
70  U_32 taille; // max size of elastic buffer is 4GB which is large enough
71 
72  void randomize(unsigned char *a) const;
73  U_I base_from_version(const archive_version & reading_ver) const;
74  unsigned char get_low_mark(const archive_version & reading_ver) const;
75  unsigned char get_high_mark(const archive_version & reading_ver) const;
76  unsigned char get_low_mark() const { return 255; };
77  unsigned char get_high_mark() const { return 254; };
78 
79  };
80 
82 
83 } // end of namespace
84 
85 #endif