rscsample04.cpp

Example of how to use bm::rsc_sparse_vector<> pre-defined set construction1. Lets assume we know which elements of the vector are not NULL

1. bm::rsc_sparse_vector<> can be constructed for this
2. call to bm::rsc_sparse_vector<>::sync will re-calculate Rank-Select index to enable fast access to elements (usually read only mode)
3. In this example we modify not NULL vector elements so it would use Rank-Select index without breaking its consistency

See also

bm::rsc_sparse_vector

bm::rsc_sparse_vector::sync

bm::rsc_sparse_vector::inc

rscsample02.cpp

/*
Copyright(c) 2002-2020 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 rscsample04.cpp
  Example of how to use bm::rsc_sparse_vector<> pre-defined set construction
 
  1. Lets assume we know which elements of the vector are not NULL
  2. bm::rsc_sparse_vector<> can be constructed for this
  3. call to bm::rsc_sparse_vector<>::sync will re-calculate Rank-Select index
     to enable fast access to elements (usually read only mode)
  4. In this example we modify not NULL vector elements so it would use
     Rank-Select index without breaking its consistency
 
 
  \sa bm::rsc_sparse_vector
  \sa bm::rsc_sparse_vector::sync
  \sa bm::rsc_sparse_vector::inc
 
  @sa rscsample02.cpp
*/
 
/*! \file rscsample04.cpp
    \brief Example: bm::rsc_sparse_vector<> known NULL elements access
 
*/
 
#include <iostream>
#include <vector>
#include <cassert>
 
#include "bm.h"
#include "bmsparsevec.h"
#include "bmsparsevec_compr.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
 
using namespace std;
 
/// Print sparse vector not NULL elements
template<typename SV> void PrintSV(const SV& sv)
{
    typename SV::const_iterator it = sv.begin();
    typename SV::const_iterator it_end = sv.end();
 
    for (size_t i = 0; it != it_end; ++it, ++i)
    {
        if (!it.is_null())
            cout << i << ": " << *it << ", ";
    }
    cout << endl;
}
 
typedef bm::sparse_vector<unsigned, bm::bvector<> >         sparse_vector_u32;
typedef bm::rsc_sparse_vector<unsigned, sparse_vector_u32 > rsc_sparse_vector_u32;
 
 
int main(void)
{
    try
    {
        // vector of not NULL elements
        bm::bvector<>         bv1 { 10, 20, 100, 200, 65536 };
        rsc_sparse_vector_u32 csv1(bv1);
 
        csv1.sync(); // build Rank-Select index for faster access
        bv1.clear(); // we don't need bv1 anymore
 
        // modify vector elements but only touch the not NULL elements
        // for fast access
        //
        csv1.set(100, 1);
        csv1.set(20, 1);
        csv1.inc(10);
        csv1.inc(65536, 1);
 
        assert(csv1.in_sync()); // make sure Rank-Select index is still alive
 
        PrintSV(csv1); // 10: 1, 20: 1, 100: 1, 200: 0, 65536: 1
    }
    catch(std::exception& ex)
    {
        std::cerr << ex.what() << std::endl;
        return 1;
    }
    
    
 
    return 0;
}