Disk ARchive  2.5.10
Full featured and portable backup and archiving tool
compressor.hpp
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2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2052 Denis Corbin
4 //
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21 
25 
26 #ifndef COMPRESSOR_HPP
27 #define COMPRESSOR_HPP
28 
29 #include "../my_config.h"
30 
31 #include "infinint.hpp"
32 #include "generic_file.hpp"
33 #include "integers.hpp"
34 #include "wrapperlib.hpp"
35 
36 namespace libdar
37 {
38 
40 
44  {
45  none = 'n',
46  gzip = 'z',
47  bzip2 = 'y',
48  lzo = 'l',
49  xz = 'x',
50  lzo1x_1_15 = 'j',
51  lzo1x_1 = 'k'
52  };
57 
60 
61  extern compression char2compression(char a);
62  extern char compression2char(compression c);
63  extern std::string compression2string(compression c);
64  extern compression string2compression(const std::string & a); // throw Erange if an unknown string is given
65 
67  class compressor : public generic_file
68  {
69  public :
70  compressor(compression algo, generic_file & compressed_side, U_I compression_level = 9);
71  // compressed_side is not owned by the object and will remains
72  // after the objet destruction
73  compressor(compression algo, generic_file *compressed_side, U_I compression_level = 9);
74  // compressed_side is owned by the object and will be
75  // deleted a destructor time
76  ~compressor();
77 
78  compression get_algo() const { return (current_algo == lzo1x_1_15 || current_algo == lzo1x_1) ? lzo : current_algo; };
79 
80  void suspend_compression();
81  void resume_compression();
82  bool is_compression_suspended() const { return suspended; };
83 
84 
85  // inherited from generic file
86  bool skippable(skippability direction, const infinint & amount) { return compressed->skippable(direction, amount); };
87  bool skip(const infinint & pos) { compr_flush_write(); compr_flush_read(); clean_read(); return compressed->skip(pos); };
88  bool skip_to_eof() { compr_flush_write(); compr_flush_read(); clean_read(); return compressed->skip_to_eof(); };
89  bool skip_relative(S_I x) { compr_flush_write(); compr_flush_read(); clean_read(); return compressed->skip_relative(x); };
90  infinint get_position() const { return compressed->get_position(); };
91 
92  protected :
93  void inherited_read_ahead(const infinint & amount) { compressed->read_ahead(amount); };
94  U_I inherited_read(char *a, U_I size) { return (this->*read_ptr)(a, size); };
95  void inherited_write(const char *a, U_I size) { (this->*write_ptr)(a, size); };
96  void inherited_sync_write() { compr_flush_write(); };
97  void inherited_flush_read() { compr_flush_read(); clean_read(); };
98  void inherited_terminate() { local_terminate(); };
99 
100  private :
101  struct xfer : public on_pool
102  {
103  wrapperlib wrap;
104  char *buffer;
105  U_I size;
106 
107  xfer(U_I sz, wrapperlib_mode mode);
108  ~xfer();
109  };
110 
111  struct lzo_block_header
112  {
113  char type; //< let the possibility to extend this architecture (for now type is fixed)
114  infinint size; //< size of the following compressed block of data
115 
116  void dump(generic_file & f);
117  void set_from(generic_file & f);
118  };
119 
120 
121  xfer *compr, *decompr; //< datastructure for bzip2 an gzip compression
122 
123  char *lzo_read_buffer; //< stores clear data (uncompressed) read from the compressed generic_file
124  char *lzo_write_buffer; //< stores the clear data to be compressed and written to the compressed generic_file
125  U_I lzo_read_size; //< number of available bytes in the read buffer for lzo decompression
126  U_I lzo_write_size; //< number of available bytes to compress and next place where to add more data in the wite buffer
127  U_I lzo_read_start; //< location of the next byte to read out from the read buffer
128  bool lzo_write_flushed; //< whether write flushing has been done
129  bool lzo_read_reached_eof; //< whether reading reached end of file and the lzo engine has to be reset to uncompress further data
130  char *lzo_compressed; //< compressed data just read or about to be written
131  char *lzo_wrkmem; //< work memory for LZO library
132 
133  generic_file *compressed;
134  bool compressed_owner;
135  compression current_algo;
136  bool suspended;
137  compression suspended_compr;
138  U_I current_level;
139 
140  void init(compression algo, generic_file *compressed_side, U_I compression_level);
141  void local_terminate();
142  U_I (compressor::*read_ptr) (char *a, U_I size);
143  U_I none_read(char *a, U_I size);
144  U_I gzip_read(char *a, U_I size);
145  // U_I zip_read(char *a, U_I size);
146  // U_I bzip2_read(char *a, U_I size); // using gzip_read, same code thanks to wrapperlib
147  U_I lzo_read(char *a, U_I size);
148 
149  void (compressor::*write_ptr) (const char *a, U_I size);
150  void none_write(const char *a, U_I size);
151  void gzip_write(const char *a, U_I size);
152  // void zip_write(char *a, U_I size);
153  // void bzip2_write(char *a, U_I size); // using gzip_write, same code thanks to wrapperlib
154  void lzo_write(const char *a, U_I size);
155 
156  void lzo_compress_buffer_and_write();
157  void lzo_read_and_uncompress_to_buffer();
158 
160 
165  void change_algo(compression new_algo, U_I new_compression_level);
166 
167 
169 
170  void change_algo(compression new_algo)
171  { change_algo(new_algo, current_level); };
172 
173 
174  void compr_flush_write(); // flush all data to compressed_side, and reset the compressor
175  // for that additional write can be uncompresssed starting at this point.
176  void compr_flush_read(); // reset decompression engine to be able to read the next block of compressed data
177  // if not called, furthur read return EOF
178  void clean_read(); // discard any byte buffered and not yet returned by read()
179  void clean_write(); // discard any byte buffered and not yet wrote to compressed_side;
180  };
181 
183 
184 } // end of namespace
185 
186 #endif
void inherited_flush_read()
Definition: compressor.hpp:97
lzo degraded algo corresponding to lzop -1
Definition: compressor.hpp:50
are defined here basic integer types that tend to be portable
void inherited_read_ahead(const infinint &amount)
Definition: compressor.hpp:93
lzma compression
Definition: compressor.hpp:49
class generic_file is defined here as well as class fichierthe generic_file interface is widely used ...
virtual infinint get_position() const =0
get the current read/write position
virtual bool skip(const infinint &pos)=0
virtual void read_ahead(const infinint &amount)
bzip2 compression
Definition: compressor.hpp:47
void inherited_terminate()
destructor-like call, except that it is allowed to throw exceptions
Definition: compressor.hpp:98
gzip compression
Definition: compressor.hpp:46
virtual bool skip_relative(S_I x)=0
skip relatively to the current position
no compression
Definition: compressor.hpp:45
bool skip_to_eof()
skip to the end of file
Definition: compressor.hpp:88
bool skip_relative(S_I x)
skip relatively to the current position
Definition: compressor.hpp:89
void inherited_sync_write()
write down any pending data
Definition: compressor.hpp:96
lzo compression
Definition: compressor.hpp:48
generic_file(gf_mode m)
main constructor
libz and libbz2 wrapper to have identical interface to these libraries.libz and libbz2 library differ...
this class encapsulates calls to libz or libbz2
Definition: wrapperlib.hpp:77
switch module to limitint (32 ou 64 bits integers) or infinint
compression class for gzip and bzip2 algorithms
Definition: compressor.hpp:67
compression
the different compression algorithm available
Definition: compressor.hpp:43
this is the interface class from which all other data transfer classes inherit
lzo degraded algo corresponding to lzo -2 to lzo -6
Definition: compressor.hpp:51
infinint get_position() const
get the current read/write position
Definition: compressor.hpp:90
void inherited_write(const char *a, U_I size)
implementation of the write() operation
Definition: compressor.hpp:95
the arbitrary large positive integer class
bool skip(const infinint &pos)
Definition: compressor.hpp:87
virtual bool skip_to_eof()=0
skip to the end of file
U_I inherited_read(char *a, U_I size)
implementation of read() operation
Definition: compressor.hpp:94
bool skippable(skippability direction, const infinint &amount)
Definition: compressor.hpp:86
compression char2compression(char a)
libdar namespace encapsulate all libdar symbols
Definition: archive.hpp:47
virtual bool skippable(skippability direction, const infinint &amount)=0