BitMagic-C++
sample4.cpp

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"
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
{
for (unsigned i = 0; i < MAX_VALUE; ++i)
{
if (rand() % 2500)
{
bv->set_bit(i);
}
}
}
static
{
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
{
// It is reccomended to optimize vector before serialization.
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
{
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.
//
// next settings provide lowest size
// 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)
{
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.
// 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);
// After a complex operation we can try to optimize bv3.
bv3.optimize();
// control check using OR on the original vectors
{
int cmp = bv_c.compare(bv3);
if (cmp != 0)
{
std::cerr << "Error: bug in serialization" << std::endl;
}
// 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::bv_statistics::max_serialize_mem
size_t max_serialize_mem
estimated maximum memory for serialization
Definition: bmfunc.h:60
MAX_VALUE
const unsigned MAX_VALUE
Definition: sample4.cpp:42
bm::bvector::set_new_blocks_strat
void set_new_blocks_strat(strategy strat)
Sets new blocks allocation strategy.
Definition: bm.h:2162
fill_bvector
static void fill_bvector(bm::bvector<> *bv)
Definition: sample4.cpp:49
bm::bvector::count
size_type count() const
population cout (count of ON bits)
Definition: bm.h:2487
bm::bv_statistics::bit_blocks
size_t bit_blocks
Number of bit blocks.
Definition: bmfunc.h:56
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)
3-operand OR : this := bv1 OR bv2
Definition: bm.h:4742
bm::deserialize
size_t deserialize(BV &bv, const unsigned char *buf, bm::word_t *temp_block=0)
Bitvector deserialization from memory.
Definition: bmserial.h:1900
BM_DECLARE_TEMP_BLOCK
#define BM_DECLARE_TEMP_BLOCK(x)
Definition: bm.h:47
bm::serializer::serialize
size_type serialize(const BV &bv, unsigned char *buf, size_t buf_size)
Bitvector serialization into memory block.
Definition: bmserial.h:1608
serialize_bvector
static unsigned char * serialize_bvector(bm::serializer< bm::bvector<> > &bvs, bm::bvector<> &bv)
Definition: sample4.cpp:76
bm::bvector::compare
int compare(const bvector< Alloc > &bvect) const
Lexicographical comparison with a bitvector.
Definition: bm.h:3224
bm::bv_statistics::gap_blocks
size_t gap_blocks
Number of GAP blocks.
Definition: bmfunc.h:57
bm::serializer::byte_order_serialization
void byte_order_serialization(bool value)
Set byte-order serialization (for cross platform compatibility)
Definition: bmserial.h:803
bm::bvector<>
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:1381
bm::serializer::gap_length_serialization
void gap_length_serialization(bool value)
Set GAP length serialization (serializes GAP levels of the original vector)
Definition: bmserial.h:797
print_statistics
static void print_statistics(const bm::bvector<> &bv)
Definition: sample4.cpp:61
bm::BM_GAP
@ BM_GAP
GAP compression is ON.
Definition: bmconst.h:145
bm::serializer
Bit-vector serialization class.
Definition: bmserial.h:77
bmserial.h
Serialization / compression of bvector<>. Set theoretical operations on compressed BLOBs.
main
int main(void)
Definition: sample4.cpp:102
bm::bv_statistics::memory_used
size_t memory_used
memory usage for all blocks and service tables
Definition: bmfunc.h:61
bm::bvector::calc_stat
void calc_stat(struct bm::bvector< Alloc >::statistics *st) const
Calculates bitvector statistics.
Definition: bm.h:3354
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
bm::bvector::set_bit
bool set_bit(size_type n, bool val=true)
Sets bit n.
Definition: bm.h:3575
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:3136
bm::bvector::statistics
Statistical information about bitset's memory allocation details.
Definition: bm.h:121