BitMagic-C++: svsample08.cpp

BitMagic-C++

svsample08.cpp

Example of how to serialize bm::sparse_vector<> container

See also
  bm::sparse_vector
  bm::sparse_vector_deserializer
  bm::sparse_vector_serial_layout
  bm::sparse_vector_serializer

/*
Copyright(c) 2002-2019 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 svsample08.cpp
Example of how to serialize bm::sparse_vector<> container
\sa bm::sparse_vector
\sa bm::sparse_vector_deserializer
\sa bm::sparse_vector_serial_layout
\sa bm::sparse_vector_serializer
*/
/*! \file svsample08.cpp
\brief Example: sparse_vector<> selective de-serialization (gather)
and range deserialization
@sa strsvsample05.cpp
*/
#include <iostream>
#include <vector>
#include "bm.h"
#include "bmsparsevec.h"
#include "bmsparsevec_serial.h"
using namespace std;
/// Print sparse vector content
template<typename SV> void PrintSV(const SV& sv)
{
cout << "size() = " << sv.size() << " : ";
auto it = sv.begin(); auto it_end = sv.end();
for (; it != it_end; ++it)
{
if (it.is_null())
cout << "NULL";
else
cout << *it;
cout << ", ";
}
cout << endl;
}
typedef bm::sparse_vector<unsigned, bm::bvector<> > svector_u32;
int main(void)
{
try
{
svector_u32 sv1(bm::use_null);
svector_u32 sv2(bm::use_null);
// add sample data using back insert iterator
//
{
auto bit = sv1.get_back_inserter();
bit = 10;
bit = 11;
bit.add_null();
bit = 13;
bit = 14;
bit.add_null(2);
bit = 256;
bit.flush();
}
PrintSV(sv1); // size() = 8 : 10, 11, NULL, 13, 14, NULL, NULL, 256,
// serialize sparse vector
bm::sparse_vector_serial_layout<svector_u32> sv_lay;
{
BM_DECLARE_TEMP_BLOCK(tb)
// optimize memory allocation of sparse vector
sv1.optimize(tb);
// construct a serializer utility class, setup serialization parameters
//
// please note, use of "set_bookmarks()" to enable fast range
// deserialization. Bookmarks somewhat increase the BLOB size but allow
// more effeiciently skip parts which we would not need (paging) and
// avoid decompression of blocks we would never need
//
// This example sets "64" as a bookmarks parameter, but you have to
// experiment with what works for you, between 4 and 512
//
// Each block corresponds to 64K vector element
// making bookmarks after each block does not make much sense
// because decode is reasonably fast and some residual throw away
// is usually ok.
//
bm::sparse_vector_serializer<svector_u32> sv_serializer;
sv_serializer. set_bookmarks(true, 64);
// serialization, creates a compressed BLOB
sv_serializer. serialize(sv1, sv_lay);
}
// get serialization pointer
const unsigned char* buf = sv_lay. buf();
// instantiate the deserializer object to do all multiple
// deserialization operations (faster)
//
bm::sparse_vector_deserializer<svector_u32> sv_deserial;
// Case 1:
// Here we define de-serialization indexes as a bit-vector (mask)
// so deserializer gathers only elements selected by the bit-vector
// all vector elements not set in the gather vector will be 0 (or NULL)
//
{
svector_u32::bvector_type bv_mask;
bv_mask. set(0);
bv_mask.set(1);
sv_deserial. deserialize(sv2, buf, bv_mask);
}
PrintSV(sv2); // size() = 8 : 10, 11, NULL, 0, 0, NULL, NULL, 0,
// Case 2:
// Here we define de-serialization indexes as a closed range [1..4]
// It is an equivalent of setting selection bits in the mask vector
// but defines the intent more clearly and works faster
{
sv_deserial. deserialize_range(sv2, buf, 1, 4);
}
PrintSV(sv2); // size() = 8 : 0, 11, NULL, 13, 14, NULL, NULL, 0,
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
return 0;
}
bm::sparse_vector_deserializer
sparse vector de-serializer
Definition: bmsparsevec_serial.h:223
bm::sparse_vector
sparse vector with runtime compression using bit transposition method
Definition: bmsparsevec.h:81
PrintSV
void PrintSV(const SV &sv)
Print sparse vector content.
Definition: svsample08.cpp:46
BM_DECLARE_TEMP_BLOCK
#define BM_DECLARE_TEMP_BLOCK(x)
Definition: bm.h:47
bm::sparse_vector_serial_layout::buf
const unsigned char * buf() const
Return serialization buffer pointer.
Definition: bmsparsevec_serial.h:106
bmsparsevec.h
Sparse constainer sparse_vector<> for integer types using bit-transposition transform.
bmsparsevec_serial.h
Serialization for sparse_vector<>
bm::sparse_vector_serial_layout
layout class for serialization buffer structure
Definition: bmsparsevec_serial.h:57
bm::bvector<>
bm::use_null
@ use_null
support "non-assigned" or "NULL" logic
Definition: bmconst.h:215
bm::bvector::set
bvector< Alloc > & set(size_type n, bool val=true)
Sets bit n if val is true, clears bit n if val is false.
Definition: bm.h:3581
bm::sparse_vector_serializer::serialize
void serialize(const SV &sv, sparse_vector_serial_layout< SV > &sv_layout)
Serialize sparse vector into a memory buffer(s) structure.
Definition: bmsparsevec_serial.h:628
bm::sparse_vector_deserializer::deserialize
void deserialize(SV &sv, const unsigned char *buf)
Definition: bmsparsevec_serial.h:243
main
int main(void)
Definition: svsample08.cpp:63
bm::sparse_vector_serializer::set_bookmarks
void set_bookmarks(bool enable, unsigned bm_interval=256)
Add skip-markers for faster range deserialization.
Definition: bmsparsevec_serial.h:183
svector_u32
bm::sparse_vector< unsigned, bm::bvector<> > svector_u32
Definition: svsample08.cpp:61
bm::sparse_vector_deserializer::deserialize_range
void deserialize_range(SV &sv, const unsigned char *buf, size_type from, size_type to)
Definition: bmsparsevec_serial.h:788
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
bm::sparse_vector_serializer
Definition: bmsparsevec_serial.h:160