BitMagic-C++
rscsample01.cpp

Example of how to use bm::rsc_sparse_vector<> template class

See also
bm::sparse_vector
bm::rsc_sparse_vector
bm::sparse_vector::push_back
bm::sparse_vector_serialize
bm::sparse_vector_deserialize
/*
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 rscsample01.cpp
Example of how to use bm::rsc_sparse_vector<> template class
\sa bm::sparse_vector
\sa bm::rsc_sparse_vector
\sa bm::sparse_vector::push_back
\sa bm::sparse_vector_serialize
\sa bm::sparse_vector_deserialize
*/
/*! \file rscsample01.cpp
\brief Example: rsc_sparse_vector<> usage
rsc_sparse_vector<> is a sparse vector which uses bit-transposition and
rank-select succinct method of compression of NULL (unassigned) values.
Unassigned values are dropped (as transposed columns) from the bit-matrix.
rsc_sparse_vector<> is basically a read-only structure, which can be used
for compact data storage and search. Random access to elements is possible
with a penalty of bit-vector Rank or Select operations.
*/
#include <iostream>
#include <vector>
#include "bmsparsevec.h"
using namespace std;
template<class SV>
void print_svector(const SV& sv, bool show_nulls = false)
{
std::cout << sv.size() << ": ";
for (unsigned i = 0; i < sv.size(); ++i)
{
if (show_nulls)
{
if (sv.is_null(i))
std::cout << "NULL, ";
else
{
typename SV::value_type v = sv.get(i);
std::cout << v << ", ";
}
}
else
{
typename SV::value_type v = sv.get(i);
std::cout << v << ", ";
}
}
std::cout << std::endl;
}
int main(void)
{
// temp buffer to avoid unnecessary re-allocations
try
{
sparse_vector_u32 sv1(bm::use_null); // use null is needed to build rsc vector
// fill in sparse vector leaving some unassigned gaps
for (unsigned i = 0; i < 15; i+=3)
{
sv1[i] = i;
}
print_svector(sv1); // print sparse vector disregard NULL values (printed as 0)
print_svector(sv1, true); // print sparse vector show NULLs (unassigned)
csv2.load_from(sv1); // load rank-select-compacted (rsc) sparse vector
// print results - it should look the same
print_svector(csv2, true);
// serialize rsc vector
// optimize memory allocation of sparse vector
csv2.optimize(tb);
bm::sparse_vector_serialize(csv2, sv_lay, tb);
// memory copy just simulates network or DB transaction
const unsigned char* buf = sv_lay.buf();
size_t buf_size = sv_lay.size();
vector<unsigned char> tmp_buf(buf_size);
::memcpy(&tmp_buf[0], buf, buf_size);
rsc_sparse_vector_u32 csv3; // target vector
int res = bm::sparse_vector_deserialize(csv3, &tmp_buf[0], tb);
if (res != 0)
{
std::cerr << "De-Serialization error!" << std::endl;
return 1;
}
if (!csv3.equal(csv2) )
{
cerr << "Error! Please report a bug to BitMagic project support." << endl;
return 1;
}
// unload rsc to sv, this makes a round-trip to an editable form
csv3.load_to(sv3);
if (!sv3.equal(sv1) )
{
std::cerr << "Error! Please report a bug to BitMagic project support." << std::endl;
return 1;
}
print_svector(sv1, true); // print sparse vector again
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
return 0;
}