BitMagic-C++
sample3.cpp
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1/*
2Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15
16For 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
38using namespace std;
39
40const 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.
45static
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
58static
60{
61 bm::bvector<>::statistics st;
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
72int 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
88
89 // Now run optimization procedure for bv1 and see statistics.
90 bv1.optimize();
91
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_type count() const BMNOEXCEPT
population cout (count of ON bits)
Definition bm.h:2194
void optimize(bm::word_t *temp_block=0, optmode opt_mode=opt_compress, statistics *stat=0)
Optimize memory bitvector's memory allocation.
Definition bm.h:3071
void set_new_blocks_strat(strategy strat)
Sets new blocks allocation strategy.
Definition bm.h:1810
bool set_bit(size_type n, bool val=true)
Sets bit n.
Definition bm.h:3617
void calc_stat(struct bm::bvector< Alloc >::statistics *st) const BMNOEXCEPT
Calculates bitvector statistics.
Definition bm.h:3393
@ BM_GAP
GAP compression is ON.
Definition bmconst.h:144
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
int main(void)
Definition sample3.cpp:72
const unsigned MAX_VALUE
Definition sample3.cpp:40