sample4.cpp

Exmaple demonstrates bitvector serialization/deserialization.

Exmaple demonstrates bitvector serialization/deserialization.For more information please visit: http://bmagic.sourceforge.net

See also
  bm::serializer
  bm::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 sample4.cpp
Exmaple demonstrates bitvector serialization/deserialization.
For more information please visit: http://bmagic.sourceforge.net
\sa bm::serializer
\sa bm::deserialize
*/
/*! \file sample4.cpp
\brief Example: bvector<> serialization/deserialization.
*/
#include <stdlib.h>
#include <iostream>
#include "bm.h"
#include "bmserial.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
using namespace std;
// This exmaple demonstrates bitvector serialization/deserialization.
const unsigned MAX_VALUE = 1000000;
// This procedure creates very dense bitvector.
// The resulting set will consists mostly from ON (1) bits
// interrupted with small gaps of 0 bits.
static
void fill_bvector(bm::bvector<>* bv)
{
for (unsigned i = 0; i < MAX_VALUE; ++i)
{
if (rand() % 2500)
{
bv->set_bit(i);
}
}
}
static
void print_statistics(const bm::bvector<>& bv)
{
bm::bvector<>::statistics st;
bv.calc_stat(&st);
cout << "Bits count:" << bv.count() << endl;
cout << "Bit blocks:" << st.bit_blocks << endl;
cout << "GAP blocks:" << st.gap_blocks << endl;
cout << "Memory used:"<< st.memory_used << endl;
cout << "Max.serialize mem.:" << st.max_serialize_mem << endl << endl;;
}
// This is fairly low level serialization method, saves into a buffer
//
static
unsigned char* serialize_bvector(bm::serializer<bm::bvector<> >& bvs,
bm::bvector<>& bv)
{
// It is good to optimize vector before serialization.
// scratch memory block
BM_DECLARE_TEMP_BLOCK(tb)
bm::bvector<>::statistics st;
bv.optimize(tb, bm::bvector<>::opt_compress, &st);
cout << "Bits count:" << bv.count() << endl;
cout << "Bit blocks:" << st.bit_blocks << endl;
cout << "GAP blocks:" << st.gap_blocks << endl;
cout << "Memory used:"<< st.memory_used << endl;
cout << "Max.serialize mem.:" << st.max_serialize_mem << endl;
// Allocate serialization buffer.
unsigned char* buf = new unsigned char[st.max_serialize_mem];
// Serialization to memory.
size_t len = bvs.serialize(bv, buf, st.max_serialize_mem);
cout << "Serialized size:" << len << endl << endl;
return buf;
}
int main(void)
{
unsigned char* buf1 = 0;
unsigned char* buf2 = 0;
try
{
bm::bvector<> bv1;
bm::bvector<> bv2;
bv2.set_new_blocks_strat(bm::BM_GAP); // set DGAP compression mode ON
fill_bvector(&bv1);
fill_bvector(&bv2);
// Prepare a serializer class
// for best performance it is best to create serilizer once and reuse it
// (saves a memory allocations). Do NOT use it concurrently.
//
bm::serializer<bm::bvector<> > bvs;
// next settings provide lowest size
bvs.byte_order_serialization(false);
bvs.gap_length_serialization(false);
// 1: serializes into a new allocated buffer (needs to be deallocated)
buf1 = serialize_bvector(bvs, bv1);
// 2: use serialization buffer class (automatic RAI, freed on destruction)
bm::serializer<bm::bvector<> >::buffer sbuf;
{
bvs.serialize(bv2, sbuf);
buf2 = sbuf.data();
auto sz = sbuf.size();
cout << "BV2 Serialized size:" << sz << endl;
}
// Serialized bvectors (buf1 and buf2) now ready to be
// saved to a database, file or send over a network.
// ...
// Deserialization.
bm::bvector<> bv3;
// As a result of desrialization bv3 will contain all bits from
// bv1 and bv3:
// bv3 = bv1 OR bv2
bm::deserialize(bv3, buf1);
bm::deserialize(bv3, buf2);
print_statistics(bv3);
// After a complex operation we can try to optimize bv3.
bv3.optimize();
print_statistics(bv3);
// control check using OR on the original vectors
{
bm::bvector<> bv_c;
bv_c.bit_or(bv1, bv2, bm::bvector<>::opt_compress);
int cmp = bv_c.compare(bv3);
if (cmp != 0)
{
std::cerr << "Error: bug in serialization" << std::endl;
}
bm::serializer<bm::bvector<> >::buffer sbuf2;
// destructive serialization, "bv_c" should not be used after
bvs.optimize_serialize_destroy(bv_c, sbuf2);
cout << "BV_C Serialized size:" << sbuf2.size() << endl;
}
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
delete [] buf1;
return 1;
}
delete [] buf1;
return 0;
}
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
BM_DECLARE_TEMP_BLOCK
#define BM_DECLARE_TEMP_BLOCK(x)
Definition bm.h:47
bmserial.h
Serialization / compression of bvector<>. Set theoretical operations on compressed BLOBs.
bmundef.h
pre-processor un-defines to avoid global space pollution (internal)
bm::bvector
Bitvector Bit-vector container with runtime compression of bits.
Definition bm.h:115
bm::bvector::bit_or
bm::bvector< Alloc > & bit_or(const bm::bvector< Alloc > &bv1, const bm::bvector< Alloc > &bv2, typename bm::bvector< Alloc >::optmode opt_mode=opt_none)
3-operand OR : this := bv1 OR bv2
Definition bm.h:5906
bm::bvector::opt_compress
@ opt_compress
compress blocks when possible (GAP/prefix sum)
Definition bm.h:137
bm::bvector::count
size_type count() const BMNOEXCEPT
population count (count of ON bits)
Definition bm.h:2401
bm::bvector::optimize
void optimize(bm::word_t *temp_block=0, optmode opt_mode=opt_compress, statistics *stat=0)
Optimize memory bitvector's memory allocation.
Definition bm.h:3635
bm::bvector::set_new_blocks_strat
void set_new_blocks_strat(strategy strat)
Sets new blocks allocation strategy.
Definition bm.h:1912
bm::bvector::set_bit
bool set_bit(size_type n, bool val=true)
Sets bit n.
Definition bm.h:4227
bm::bvector::compare
int compare(const bvector< Alloc > &bvect) const BMNOEXCEPT
Lexicographical comparison with a bitvector.
Definition bm.h:3744
bm::bvector::calc_stat
void calc_stat(struct bm::bvector< Alloc >::statistics *st) const BMNOEXCEPT
Calculates bitvector statistics.
Definition bm.h:3978
bm::serializer
Bit-vector serialization class.
Definition bmserial.h:76
bm::serializer::gap_length_serialization
void gap_length_serialization(bool value) BMNOEXCEPT
Set GAP length serialization (serializes GAP levels of the original vector).
Definition bmserial.h:1272
bm::serializer::byte_order_serialization
void byte_order_serialization(bool value) BMNOEXCEPT
Set byte-order serialization (for cross platform compatibility).
Definition bmserial.h:1278
bm::serializer::optimize_serialize_destroy
void optimize_serialize_destroy(BV &bv, typename serializer< BV >::buffer &buf)
Bitvector serialization into buffer object (resized automatically) Input bit-vector gets optimized an...
Definition bmserial.h:2265
bm::serializer::serialize
size_type serialize(const BV &bv, unsigned char *buf, size_t buf_size)
Bitvector serialization into memory block.
Definition bmserial.h:2703
bm::BM_GAP
@ BM_GAP
GAP compression is ON.
Definition bmconst.h:148
bm::deserialize
size_t deserialize(BV &bv, const unsigned char *buf, bm::word_t *temp_block=0, const bm::bv_ref_vector< BV > *ref_vect=0)
Bitvector deserialization from a memory BLOB.
Definition bmserial.h:3137
main
int main(void)
Definition sample1.cpp:43
print_statistics
static void print_statistics(const bm::bvector<> &bv)
Definition sample3.cpp:61
fill_bvector
static void fill_bvector(bm::bvector<> *bv1, bm::bvector<> *bv2)
Definition sample3.cpp:48
MAX_VALUE
const unsigned MAX_VALUE
Definition sample3.cpp:42
serialize_bvector
static unsigned char * serialize_bvector(bm::serializer< bm::bvector<> > &bvs, bm::bvector<> &bv)
Definition sample4.cpp:78
bm::bv_statistics::gap_blocks
size_t gap_blocks
Number of GAP blocks.
Definition bmfunc.h:58
bm::bv_statistics::bit_blocks
size_t bit_blocks
Number of bit blocks.
Definition bmfunc.h:57
bm::bv_statistics::max_serialize_mem
size_t max_serialize_mem
estimated maximum memory for serialization
Definition bmfunc.h:61
bm::bv_statistics::memory_used
size_t memory_used
memory usage for all blocks and service tables
Definition bmfunc.h:62
bm::bvector::statistics
Statistical information about bitset's memory allocation details.
Definition bm.h:125