使用boost :: dynamic_bitset作为键值对序列化boost :: bimap [英] Serialize boost::bimap with boost::dynamic_bitset as key value pair

问题描述

我有兴趣对包含boost::dynamic_bitset的boost::bimap进行序列化，以便我可以保存它并在需要时加载回去.我已经尝试过这样做，但是却遇到很多错误.我随身携带的代码如下.

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;
}

我该怎么办?.

EDIT_1:

在Eclispse中显示编译器和链接器设置(因为在@sehe提供的答案代码中出现了一些错误).

Showing the comiler and linker setting in the Eclispse(because I get some errors with the answer code provided @sehe).

EDIT_2

在Linux终端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

编辑3 使用g++ -std=c++14 -Os -Wall -pedantic -pthread main.cpp -lboost_serialization && ldd a.out我得到以下信息

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&)'

推荐答案

1. 哇.您使用该哈希函数并不是为了提高性能.

1. Wow. You're not aiming for performance with that hash function.

• 您要复制每个键/值散列上的所有块(例如，在查找时，在插入时)
• 您更好从不希望使用协程，因为该线程局部静态将使您的生活痛苦不堪

• 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

请参阅下面的我的奖金"部分

See my BONUS section below

为什么这个笨拙的舞蹈(简化代码):

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);

怎么了

auto left_iter = index.left.begin();

序列化时，您认为迭代器的有效性是什么? (请参见迭代器无效规则)

oa << left_iter;

我认为从存储加载新的数据结构算作重新分配".显然，这里的迭代器或对其他数据结构的引用毫无意义.

I think loading a new datastructure from storage counts as "reallocation". Iterators or references to another datastructure are obviously meaningless here.

Erm.现在确实变得令人困惑.

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);

您称其为第一个右元素"，但您做了其他事情:找到与first_left键相对应的迭代器(它很可能是右侧的最后一个元素.另外请注意，由于右侧bimap的multiset_of，可能有多个匹配项，您随机使用第一个.

You call it the "first right element", but you do something ELSE: you find the iterator corresponding to the first_left key (which may well be the last element on the right. Also note that since the right hand side of the bimap is multiset_of, there might be multiple matches and you random use the first.

(注意:pos是left_iter值的无用重复)

(Side note: pos is a useless duplication of left_iter's value)

请参阅3.

oa << right_iter;

变量:

Varia:

• 确保以二进制文件打开文件

• make sure you open the files as binary

std::ofstream ofs("binaryfile", std::ios::binary);
std::ifstream ifs("binaryfile", std::ios::binary);

为什么用值语义index_reference命名容器?只是不必要地造成混淆

why do you name a container with value-semantics index_reference? That's just unnecessarily confusing

真正的问题

我想，真正的问题可能是我如何序列化Bitset s?".谨在此通知您，我在2015年写下了必需的内容:如何序列化boost :: dynamic_bitset?，并且pull请求已被接受到Boost 从版本1.64开始的请求中.

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.

因此，您可以坐下来，,一口茶，包括:

So, you can sit back, sip your tea and include:

#include <boost/dynamic_bitset/serialization.hpp>

全部完成.

既然序列化实现了最小拷贝序列化，那么为什么不使用它来为哈希函数提供动力呢?序列化机制将为您提供所需的私有访问权限.

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.

我以前在hash<>专业领域滥用序列化管道:

I've abused serialization plumbing for hash<> specializations before: Hash an arbitrary precision value (boost::multiprecision::cpp_int)

在Coliru上直播

#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;
    }
}

打印

# Writing binary file ... 
# Loading binary file ... 

没问题.

真的，省去了麻烦.由于您的用法清楚地表明您不希望 unordered 语义，因此只需使其有序即可:

Really, save yourself trouble. Since your usage clearly indicates you do not want unordered semantics, just make it ordered:

在Coliru上直播

#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;
    }
}

最多36行，不到剩下的代码的一半.

Down to 36 lines, less than half the code left.

这篇关于使用boost :: dynamic_bitset作为键值对序列化boost :: bimap的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！