Disk ARchive  2.5.0
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mem_cluster.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
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9 //
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20 /*********************************************************************/
21 
25 
26 
27 
28 #ifndef MEM_CLUSTER_HPP
29 #define MEM_CLUSTER_HPP
30 
31 #include "../my_config.h"
32 #include "mem_allocator.hpp"
33 
34 
35 namespace libdar
36 {
37 
38 
41 
42  class mem_cluster : public mem_allocator
43  {
44  public:
45  mem_cluster(U_I x_block_size, //< block size that will be allocated from this mem_cluster
46  U_I table_size_64, //< the total number of block in this mem_cluster is table_size_64 * 64
47  mem_manager *x_holder); //< this is the object that holds this mem_cluster object
48  mem_cluster(const mem_cluster & ref): mem_allocator(ref) { throw SRC_BUG; };
49  const mem_cluster & operator = (const mem_cluster & ref) { throw SRC_BUG; };
50  ~mem_cluster();
51 
53  bool is_full() const { return available_blocks == 0; };
54 
56  bool is_empty() const { return available_blocks == max_available_blocks; };
57 
59  void *alloc();
60 
62  U_I get_block_size() const { return block_size; };
63 
65  std::string dump() const;
66 
68  virtual void release(void *ptr);
69 
70 #ifdef LIBDAR_DEBUG_MEMORY
71  virtual U_I max_percent_full() const { return (max_available_blocks - min_avail_reached)*100/max_available_blocks; };
72 #else
73  virtual U_I max_percent_full() const { return 0; };
74 #endif
75 
76  private:
77  static const U_64 FULL = ~(U_64)(0); //< this is 1111...111 integer in binary notation
78  static const U_64 HALF = (~(U_64)(0)) >> 1; //< this is 0111...111 integer in binary notation
79  static const U_64 LEAD = ~((~(U_64)(0)) >> 1); //< this is 1000...000 integer in binary notation
80 
81  // the memory obtained by that object is split in two parts:
82  // - the alloc_table which tells what block is sub-allocated or not
83  // - the alloc_area which contains all the blocks that can be sub-allocated
84  // all this memory is obtained at once and the address to release at object destructor is given by alloc_table
85  // because it takes place at the beginning of the obtained memory
86  char *alloc_area; //< points to the allocatable memory block
87  U_I alloc_area_size; //< size of sub-allocatable memory in bytes (excluding the alloc_table part of the allocated memory used for management)
88  U_I block_size; //< size of requested blocks
89  U_64 *alloc_table; //< maps the blocks of the allocated memory that have been (sub-)allocated
90  U_I alloc_table_size; //< size of the map (in number of U_64 integers)
91  U_I next_free_in_table; //< next U_64 to look at for a request of block allocation
92  U_I available_blocks; //< current number of available block in alloc
93  U_I max_available_blocks; //< max available block in alloc
94 #ifdef LIBDAR_DEBUG_MEMORY
95  U_I min_avail_reached; //< records the max fullfilment reached
96 #endif
97 
98  U_I find_free_slot_in(U_I table_integer) const;
99  void set_slot_in(U_I table_integer, U_I bit_offset, bool value);
100  std::string examination_status() const; // debugging, displays the list of allocated blocks that remain
101  };
102 
104 
105 } // end of namespace
106 
107 #endif
this is the base class of object that can provide dynamically allocated memory blocks ...