Serialize boost::bimap with boost::dynamic_bitset as key value pair
I am interested to serialize a boost::bimap containing boost::dynamic_bitset so that I can save that and load back when needed. I have made an attempt to do that but I get many errors. The code that I have with me is as below.
// Example program
#include <iostream>
#include <string>
#include <fstream>
#include <boost/bimap.hpp>
#include <boost/dynamic_bitset.hpp>
#include <boost/bimap/unordered_set_of.hpp>
#include <boost/bimap/unordered_multiset_of.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/serialization/vector.hpp>
namespace std {
template <typename Block, typename Alloc>
struct hash<boost::dynamic_bitset<Block, Alloc> > {
using bitset_type = boost::dynamic_bitset<Block, Alloc>;
using block_type = typename bitset_type::block_type ;
size_t operator()(boost::dynamic_bitset<Block, Alloc> const& bs) const
{
thread_local static std::vector<block_type> block_data;
auto blocks = bs.num_blocks();
block_data.assign(blocks, 0);
to_block_range(bs, block_data.begin());
return boost::hash<std::vector<block_type>>()(block_data);
}
};
}
namespace {
template <typename Block>
struct SerializableType {
boost::dynamic_bitset<Block> x;
private:
friend class boost::serialization::access;
template <class Archive> void serialize(Archive &ar, const unsigned int) {
ar & BOOST_SERIALIZATION_NVP(x);
}
};
}
namespace bimaps = boost::bimaps;
typedef boost::dynamic_bitset<> Bitset;
typedef boost::bimap<
bimaps::unordered_set_of<Bitset, std::hash<Bitset>>,
bimaps::unordered_multiset_of<Bitset, std::hash<Bitset> > > bimap_reference;
typedef bimap_reference::value_type position;
bimap_reference index;
int main() {
std::string val = "1010110110101010101";
std::string key = "10010";
boost::dynamic_bitset<> bits = boost::dynamic_bitset<> (val);
boost::dynamic_bitset<> pos_bits = boost::dynamic_bitset<> (key);
index.insert(position(pos_bits, bits));
std::ofstream ofs("binaryfile");
boost::archive::binary_oarchive oa(ofs);
oa << BOOST_SERIALIZATION_NVP(index);
index::const_iterator iter = index.begin();
// first left elelemt of bimap
boost::dynamic_bitset<> first_left = iter->left;
const bimap_reference::left_iterator left_iter = index.left.find(first_left);
oa << left_iter;
// first right element of bimap
auto pos = index.left.find(first_left);
const bimap_reference::right_iterator right_iter = index.right.find(pos->second);
oa << right_iter;
std::cout <<"# done" << std::endl;
ofs.close();
std::cout <<"# Loading binary file ... " << std::endl;
std::ifstream ifs("binaryfile"); // name of loading file
boost::archive::binary_iarchive ia(ifs);
ia >> index;
bimap_reference::left_iterator left_iter;
ia >> left_iter;
bimap_reference::right_iterator right_iter;
ia >> right_iter;
std::cout<<"# done" << std::endl;
ifs.close();
return 0;
}
How can I do it?.
EDIT_1:
Showing the comiler and linker setting in the Eclispse(because I get some errors with the answer code provided @sehe).
EDIT_2
Command used on linux terminal g++ -std=c++14 -Os -Wall -pedantic -pthread main.cpp -lboost_serialization && ./a.out
Errors I get with the first answer code when tried in linux terminal and eclipse IDE.
/tmp/cc71hTC2.o: In function `boost::archive::detail::common_iarchive<boost::archive::binary_iarchive>::vload(boost::archive::class_name_type&)':
main.cpp:(.text._ZN5boost7archive6detail15common_iarchiveINS0_15binary_iarchiveEE5vloadERNS0_15class_name_typeE[_ZN5boost7archive6detail15common_iarchiveINS0_15binary_iarchiveEE5vloadERNS0_15class_name_typeE]+0x1): undefined reference to `boost::archive::basic_binary_iarchive<boost::archive::binary_iarchive>::load_override(boost::archive::class_name_type&)'
/tmp/cc71hTC2.o: In function `void boost::serialization::throw_exception<boost::archive::archive_exception>(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost13serialization15throw_exceptionINS_7archive17archive_exceptionEEEvRKT_[_ZN5boost13serialization15throw_exceptionINS_7archive17archive_exceptionEEEvRKT_]+0x1a): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/cc71hTC2.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::exception_detail::error_info_injector<boost::archive::archive_exception> const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC2ERKS4_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS4_]+0x18): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/cc71hTC2.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::exception_detail::error_info_injector<boost::archive::archive_exception> const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC1ERKS4_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS4_]+0x19): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/cc71hTC2.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC2ERKS3_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS3_]+0xe): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/cc71hTC2.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC1ERKS3_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS3_]+0x14): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
collect2: error: ld returned 1 exit status
EDIT 3
Using g++ -std=c++14 -Os -Wall -pedantic -pthread main.cpp -lboost_serialization && ldd a.out I get the following info
/tmp/ccBH8KfT.o: In function `boost::archive::detail::common_iarchive<boost::archive::binary_iarchive>::vload(boost::archive::class_name_type&)':
main.cpp:(.text._ZN5boost7archive6detail15common_iarchiveINS0_15binary_iarchiveEE5vloadERNS0_15class_name_typeE[_ZN5boost7archive6detail15common_iarchiveINS0_15binary_iarchiveEE5vloadERNS0_15class_name_typeE]+0x1): undefined reference to `boost::archive::basic_binary_iarchive<boost::archive::binary_iarchive>::load_override(boost::archive::class_name_type&)'
/tmp/ccBH8KfT.o: In function `void boost::serialization::throw_exception<boost::archive::archive_exception>(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost13serialization15throw_exceptionINS_7archive17archive_exceptionEEEvRKT_[_ZN5boost13serialization15throw_exceptionINS_7archive17archive_exceptionEEEvRKT_]+0x1a): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/ccBH8KfT.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::exception_detail::error_info_injector<boost::archive::archive_exception> const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC2ERKS4_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS4_]+0x18): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/ccBH8KfT.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::exception_detail::error_info_injector<boost::archive::archive_exception> const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC1ERKS4_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS4_]+0x19): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/ccBH8KfT.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC2ERKS3_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS3_]+0xe): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
/tmp/ccBH8KfT.o: In function `boost::exception_detail::error_info_injector<boost::archive::archive_exception>::error_info_injector(boost::archive::archive_exception const&)':
main.cpp:(.text._ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC1ERKS3_[_ZN5boost16exception_detail19error_info_injectorINS_7archive17archive_exceptionEEC5ERKS3_]+0x14): undefined reference to `boost::archive::archive_exception::archive_exception(boost::archive::archive_exception const&)'
Solution
Wow. You're not aiming for performance with that hash function.
- you're copying all the blocks on every key/value hash (e.g. on lookup, on insert)
- you better never wish to use co-routines because that thread-local static will make your life miserable
See my BONUS section below
Why this awkward dance (simplified code):
auto iter = index.begin(); // first left element of bimap BS first_left = iter->left; Index::left_iterator left_iter = index.left.find(first_left);What is wrong with
auto left_iter = index.left.begin();What do you think is the validity of an iterator when serialized? (See Iterator invalidation rules)
oa << left_iter;I think loading a new datastructure from storage counts as "reallocation". Iterators or references to another datastructure are obviously meaningless here.
Erm. Now it's really getting confusing.
// first right element of bimap auto pos = index.left.find(first_left); Index::right_iterator right_iter = index.right.find(pos->second);You call it the "first right element", but you do something ELSE: you find the iterator corresponding to the
first_leftkey (which may well be the last element on the right. Also note that since the right hand side of the bimap ismultiset_of, there might be multiple matches and you random use the first.(Side note:
posis a useless duplication ofleft_iter's value)See 3.
oa << right_iter;Varia:
make sure you open the files as binary
std::ofstream ofs("binaryfile", std::ios::binary); std::ifstream ifs("binaryfile", std::ios::binary);why do you name a container with value-semantics
index_reference? That's just unnecessarily confusingSerializableTypeis unusedBOOST_SERIALIZATION_NVPis meaningless for binary archives (nodes have no names in those)
The Real Question
I suppose, the real question might have been "how do I serialize the Bitsets?". I'm happy to inform you I wrote the required bits in 2015: How to serialize boost::dynamic_bitset? and the pull request has been accepted into Boost starting with version 1.64.
So, you can sit back, sip your tea and include:
#include <boost/dynamic_bitset/serialization.hpp>
All done.
The BONUS Section
Since that serialization achieves a minimal-copy serialization, why not use it to power the hash function? The serialization mechanism will provide you the required private access.
I've abused serialization plumbing for hash<> specializations before: Hash an arbitrary precision value (boost::multiprecision::cpp_int)
Putting It All Together
#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/bimap.hpp>
#include <boost/bimap/unordered_multiset_of.hpp>
#include <boost/bimap/unordered_set_of.hpp>
#include <boost/dynamic_bitset/serialization.hpp>
#include <fstream>
#include <iostream>
#include <string>
#include <boost/iostreams/device/back_inserter.hpp>
#include <boost/iostreams/stream_buffer.hpp>
#include <boost/iostreams/stream.hpp>
#include <boost/functional/hash.hpp>
namespace serial_hashing { // see https://stackoverflow.com/questions/30097385/hash-an-arbitrary-precision-value-boostmultiprecisioncpp-int
namespace io = boost::iostreams;
struct hash_sink {
hash_sink(size_t& seed_ref) : _ptr(&seed_ref) {}
typedef char char_type;
typedef io::sink_tag category;
std::streamsize write(const char* s, std::streamsize n) {
boost::hash_combine(*_ptr, boost::hash_range(s, s+n));
return n;
}
private:
size_t* _ptr;
};
template <typename T> struct hash_impl {
size_t operator()(T const& v) const {
using namespace boost;
size_t seed = 0;
{
iostreams::stream<hash_sink> os(seed);
archive::binary_oarchive oa(os, archive::no_header | archive::no_codecvt);
oa << v;
}
return seed;
}
};
}
namespace std {
template <typename Block, typename Alloc> struct hash<boost::dynamic_bitset<Block, Alloc> >
: serial_hashing::hash_impl<boost::dynamic_bitset<Block, Alloc> >
{};
} // namespace std
namespace bimaps = boost::bimaps;
using Bitset = boost::dynamic_bitset<>;
typedef boost::bimap<
bimaps::unordered_set_of<Bitset, std::hash<Bitset> >,
bimaps::unordered_multiset_of<Bitset, std::hash<Bitset> > > Index;
int main() {
using namespace std::string_literals;
{
std::cout << "# Writing binary file ... " << std::endl;
Index index;
index.insert({Bitset("10010"s), Bitset("1010110110101010101"s)});
std::ofstream ofs("binaryfile", std::ios::binary);
boost::archive::binary_oarchive oa(ofs);
oa << index;
}
{
std::cout << "# Loading binary file ... " << std::endl;
std::ifstream ifs("binaryfile", std::ios::binary); // name of loading file
boost::archive::binary_iarchive ia(ifs);
Index index;
ia >> index;
}
}
Prints
# Writing binary file ...
# Loading binary file ...
No problem.
POST SCRIPTUM
Really, save yourself trouble. Since your usage clearly indicates you do not want unordered semantics, just make it ordered:
#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/bimap.hpp>
#include <boost/bimap/multiset_of.hpp>
#include <boost/dynamic_bitset/serialization.hpp>
#include <fstream>
#include <iostream>
namespace bimaps = boost::bimaps;
using Bitset = boost::dynamic_bitset<>;
typedef boost::bimap<bimaps::set_of<Bitset>, bimaps::multiset_of<Bitset>> Index;
int main() {
using namespace std::string_literals;
{
std::cout << "# Writing binary file ... " << std::endl;
Index index;
index.insert({Bitset("10010"s), Bitset("1010110110101010101"s)});
std::ofstream ofs("binaryfile", std::ios::binary);
boost::archive::binary_oarchive oa(ofs);
oa << index;
}
{
std::cout << "# Loading binary file ... " << std::endl;
std::ifstream ifs("binaryfile", std::ios::binary); // name of loading file
boost::archive::binary_iarchive ia(ifs);
Index index;
ia >> index;
}
}
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