svsample02.cpp

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/*
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 svsample02.cpp
  Example of how to serialize bm::sparse_vector<> template class
 
  \sa bm::sparse_vector
  \sa bm::sparse_vector<>::push_back
  \sa bm::sparse_vector<>::equal
  \sa bm::sparse_vector_serialize
  \sa bm::sparse_vector_deserialize
  \sa bm::sparse_vector_serializer
  \sa bm::sparse_vector_deserializer
 
  \sa rscsample05.cpp
*/
 
/*! \file svsample02.cpp
    \brief Example: sparse_vector<> serialization
 
*/
 
#include <iostream>
#include <vector>
#include <assert.h>
 
#include "bm.h"
#include "bmsparsevec.h"
#include "bmsparsevec_serial.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
 
using namespace std;
 
typedef bm::sparse_vector<unsigned, bm::bvector<> > sparse_vector_u32;
typedef bm::sparse_vector<int, bm::bvector<> >      sparse_vector_i32;
 
typedef bm::sparse_vector_serializer<sparse_vector_u32>   sv_serializer_type;
typedef bm::sparse_vector_deserializer<sparse_vector_u32> sv_deserializer_type;
 
/// Demo 1
/// Simple one function call serialization
///
static
void SDemo1()
{
    sparse_vector_u32 sv1;
    sparse_vector_u32 sv2;
 
    for (unsigned i = 0; i < 128000; ++i)
    {
        sv1.push_back(8);
    }
 
    // optimize memory allocation of sparse vector
    sv1.optimize();
 
    bm::sparse_vector_serial_layout<sparse_vector_u32> sv_lay;
    bm::sparse_vector_serialize(sv1, sv_lay);
 
    // copy serialization buffer to some other location
    // to simulate data-base storage or network transaction
    //
    const unsigned char* buf = sv_lay.buf();
    size_t buf_size = sv_lay.size();
    cout << buf_size << endl;
 
    vector<unsigned char> tmp_buf(buf_size);
    ::memcpy(&tmp_buf[0], buf, buf_size);
 
    int res = bm::sparse_vector_deserialize(sv2, &tmp_buf[0]);
    if (res != 0)
    {
        cerr << "De-Serialization error!" << endl;
        return;
    }
    if (!sv1.equal(sv2) )
    {
        cerr << "Error! Please report a bug to BitMagic project support." << endl;
        return;
    }
}
 
/// Demo 2
/// - Reuseable serializer/deserilaizer classes
/// - Shows serializarion with XOR compression enabled
///
/// Reusable serializer is better (works faster) when we need to serialize/deserialize a bunch of vectors
/// use of serializer also offers a better control on serialization options (like XOR compression)
///
static
void SDemo2()
{
    sparse_vector_u32 sv1(bm::use_null); // NULL-able vector
    sparse_vector_u32 sv2(bm::use_null);
 
    // not the fastest way to init the vector but it will do for an example
    //
    for (unsigned i = 0; i < 128000; i+=2)
        sv1.set(i, 8);
    for (unsigned i = 128000; i < 128000*4; i+=256)
        sv1.set(i, 7);
 
 
    BM_DECLARE_TEMP_BLOCK(tb)
    sv1.optimize(tb);
    sv2 = sv1; // copy sv1
 
    sv_serializer_type sv_ser;
    sv_deserializer_type sv_dser;
    bm::sparse_vector_serial_layout<sparse_vector_u32> sv_lay0;
 
    // the data pattern will allow XOR compression
    // lets try to enable it!
 
    sv_ser.enable_xor_compression();
    assert(sv_ser.is_xor_ref());
    sv_ser.serialize(sv1, sv_lay0);
 
    // Get BLOB pointer and size
    const unsigned char* buf = sv_lay0.data();
    size_t sz = sv_lay0.size();
    cout << "XOR compression enabled size=" << sz << endl;
 
    // deserialize from the memory pointer
    //
    {
        sparse_vector_u32 sv3(bm::use_null);
        sv_dser.deserialize(sv3, buf);
        assert(sv3.equal(sv1));
 
        // here we do read-only deserialization
        // RO vector is immutable (which is ok in many cases)
        //
        // Immutable vectors drops the over-allocation overhead
        // necessary for fast modifications which makes it more succinct.
        //
        // Another advantage or RO vectors is that it may be a bit faster
        // due to reduced memory fragmentation.
        //
        // Please note that RO deserialization will be a bit slower
        //
 
        sparse_vector_u32 sv4(bm::use_null);
        {
            sv_deserializer_type sv_dser_ro;
            sv_dser_ro.set_finalization(bm::finalization::READONLY);
            sv_dser_ro.deserialize(sv4, buf);
        }
 
        assert(sv4.is_ro());
        bool eq = sv3.equal(sv4);
        assert(eq); (void)eq;
 
        // compute memory profile for RO and RW vectors
        // to illustrate the case when RO takes less RAM
        //
        sparse_vector_u32::statistics st3, st4;
        sv3.calc_stat(&st3);
        sv4.calc_stat(&st4);
 
        cout << "RW vector mem=" << st3.memory_used << endl;
        cout << "RO vector mem=" << st4.memory_used << endl;
    }
 
 
    // disbale XOR compression
    // please note that we re-use serializer and deserializer instances
    // to save construction costs (memory allocations, etc)
    //
 
    sv_ser.disable_xor_compression();
    assert(!sv_ser.is_xor_ref());
 
    sv_ser.serialize(sv2, sv_lay0);
 
    buf = sv_lay0.data();
    sz = sv_lay0.size();
    cout << "XOR compression disabled size=" << sz << endl;
 
    // deserialize from the memory pointer
    //
    {
        sparse_vector_u32 sv3(bm::use_null);
        sv_dser.deserialize(sv3, buf);
        assert(sv3.equal(sv1));
    }
 
}
 
int main(void)
{
    try
    {
        cout << "Demo 1" << endl;
        SDemo1();
 
        cout << "Demo 2" << endl;
        SDemo2();
    }
    catch(std::exception& ex)
    {
        std::cerr << ex.what() << std::endl;
        return 1;
    }
 
    return 0;
}