BitMagic-C++: sample18.cpp

BitMagic-C++

sample18.cpp

Example of bulk insert iterator

See also
  bm::bvector::insert_iterator
  bm::bvector::bulk_insert_iterator

/*
Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
For more information please visit: http://bitmagic.io
*/
/** \example sample18.cpp
Example of bulk insert iterator
\sa bm::bvector::insert_iterator
\sa bm::bvector::bulk_insert_iterator
*/
/*! \file sample18.cpp
\brief Example: bulk insert iterator
Bulk insert iterator uses internal buffer to accumulate a batch
of bit indexes and flush it faster.
This delay makes its behavior different from classic
deterministic STL iterators.
*/
#include <stdlib.h>
#include <iostream>
#include "bm.h"
using namespace std;
int main(void)
{
try
{
bm::bvector<> bv;
// use regular insert iterator to add bits to vector
bm::bvector<>::insert_iterator iit = bv. inserter();
for (unsigned i = 5; i != 0; --i)
{
iit = i;
cout << bv. count() << ", "; // note that bits are added immediately
}
cout << endl;
bv. clear(); // clear the vector
// bulk insert adds bits faster (on sorted data), but provides no guarantee
// that it happens immediately. Instead it uses an internal buffer to accumulate it first
// and periodically flushes it into the bit-vector.
//
{
bm::bvector<>::bulk_insert_iterator bulk_iit(bv);
for (bm::bvector<>::size_type i = 5; i != 0; --i)
{
bulk_iit = i;
cout << bv.count() << ", "; // note that bits are NOT added immediately
}
cout << endl;
} // <= scope is a point when data flush happens (on destruction)
cout << bv.count() << endl; // now all bits are added
bv.clear();
// bulk content flash can be forced, before going out-of-scope
// which may be problematic due to possible exceptions from the destructor.
//
{
bm::bvector<>::bulk_insert_iterator bulk_iit(bv);
for (bm::bvector<>::size_type i = 0; i < 5; ++i)
bulk_iit = i;
cout << bv.count() << endl; // not added yet
bulk_iit. flush(); // force bulk iterator to submit the data
cout << bv.count() << endl; // now added!
}
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
return 0;
}
bm::bvector::insert_iterator
Output iterator iterator designed to set "ON" bits based on input sequence of integers (bit indeces).
Definition: bm.h:377
main
int main(void)
Definition: sample18.cpp:42
bm::bvector<>
bm::bvector::count
size_type count() const BMNOEXCEPT
population cout (count of ON bits)
Definition: bm.h:2194
bm::bvector::clear
void clear(const size_type *ids, size_type ids_size, bm::sort_order so=bm::BM_UNKNOWN)
clear list of bits in this bitset
Definition: bm.h:3546
bm::bvector::inserter
insert_iterator inserter()
Definition: bm.h:1245
bm::bvector::bulk_insert_iterator::flush
void flush()
Definition: bm.h:563
bm::bvector::bulk_insert_iterator
Output iterator iterator designed to set "ON" bits based on input sequence of integers.
Definition: bm.h:461
bm::bvector::size_type
bm::id_t size_type
Definition: bm.h:117
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.