BitMagic-C++
sample3.cpp
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1 /*
2 Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
3 
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7 
8  http://www.apache.org/licenses/LICENSE-2.0
9 
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15 
16 For more information please visit: http://bitmagic.io
17 */
18 
19 /** \example sample3.cpp
20  Exmaple demonstrates using bitvectors with different initial
21  block allocation strategy.
22  Bitvector 1 (bv1) by default working without RLE compression option
23  (best performance, maximum memory consumption).
24  Bitvector 2 (bv2) will be working in compression mode and use less memory.
25 
26  \sa bm::bvector<>::set_new_blocks_strat()
27 
28  For more information please visit: http://bmagic.sourceforge.net
29 
30 */
31 /*! \file sample3.cpp
32  \brief Example: bvector<> with different allocation/compression strategies
33 */
34 #include <stdlib.h>
35 #include <iostream>
36 #include "bm.h"
37 
38 using namespace std;
39 
40 const unsigned MAX_VALUE = 1000000;
41 
42 // This procedure creates very dense bitvectors.
43 // The resulting set will consists mostly from ON (1) bits
44 // interrupted with small gaps of 0 bits.
45 static
47 {
48  for (unsigned i = 0; i < MAX_VALUE; ++i)
49  {
50  if (rand() % 2500)
51  {
52  bv1->set_bit(i);
53  bv2->set_bit(i);
54  }
55  }
56 }
57 
58 static
60 {
62  bv.calc_stat(&st);
63 
64  cout << "Bits count:" << bv.count() << endl;
65  cout << "Bit blocks:" << st.bit_blocks << endl;
66  cout << "GAP blocks:" << st.gap_blocks << endl;
67  cout << "Memory used:"<< st.memory_used << endl;
68  cout << "Max.serialize mem.:" << st.max_serialize_mem << endl << endl;;
69 }
70 
71 
72 int main(void)
73 {
74  try
75  {
76  bm::bvector<> bv1;
77  bm::bvector<> bv2;
78 
79  bv2.set_new_blocks_strat(bm::BM_GAP); // set DGAP compression mode ON
80 
81  fill_bvector(&bv1, &bv2); // Fill both bvectors with the same values
82 
83  // For a given distrubution statistics should demonstrate
84  // lower memory consumption for the vector with compression
85 
86  print_statistics(bv1);
87  print_statistics(bv2);
88 
89  // Now run optimization procedure for bv1 and see statistics.
90  bv1.optimize();
91 
92  print_statistics(bv1);
93  }
94  catch(std::exception& ex)
95  {
96  std::cerr << ex.what() << std::endl;
97  }
98 
99  return 0;
100 }
101 
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
size_t gap_blocks
Number of GAP blocks.
Definition: bmfunc.h:57
void optimize(bm::word_t *temp_block=0, optmode opt_mode=opt_compress, statistics *stat=0)
Optimize memory bitvector&#39;s memory allocation.
Definition: bm.h:3136
size_t max_serialize_mem
estimated maximum memory for serialization
Definition: bmfunc.h:60
void set_new_blocks_strat(strategy strat)
Sets new blocks allocation strategy.
Definition: bm.h:2162
GAP compression is ON.
Definition: bmconst.h:145
Statistical information about bitset&#39;s memory allocation details.
Definition: bm.h:121
size_t memory_used
memory usage for all blocks and service tables
Definition: bmfunc.h:61
static void print_statistics(const bm::bvector<> &bv)
Definition: sample3.cpp:59
static void fill_bvector(bm::bvector<> *bv1, bm::bvector<> *bv2)
Definition: sample3.cpp:46
size_type count() const
population cout (count of ON bits)
Definition: bm.h:2487
const unsigned MAX_VALUE
Definition: sample3.cpp:40
void calc_stat(struct bm::bvector< Alloc >::statistics *st) const
Calculates bitvector statistics.
Definition: bm.h:3354
size_t bit_blocks
Number of bit blocks.
Definition: bmfunc.h:56
int main(void)
Definition: sample3.cpp:72
bool set_bit(size_type n, bool val=true)
Sets bit n.
Definition: bm.h:3575