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我有兴趣序列化一个boost::bimap包含boost::dynamic_bitset，以便我可以保存它并在需要时加载回来。我已经尝试过这样做，但我遇到了很多错误。我随身携带的代码如下。

// 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;
}

我该怎么做？。

编辑_1：

在中显示编译器和链接器设置Eclispse（因为我在@sehe 提供的答案代码中遇到了一些错误）。

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EDIT_2

linux终端上使用的命令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

/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&)'
4

1 回答 1

2

  1. 哇。您的目标不是使用该哈希函数来提高性能。

    • 您正在复制每个键/值哈希上的所有块（例如在查找时，在插入时）
    • 你最好永远不要使用协同程序，因为线程本地静态会让你的生活变得悲惨

    请参阅下面的奖金部分

  2. 为什么会出现这种尴尬的舞蹈（简化代码）：

    auto iter = index.begin();

// first left element of bimap
BS first_left = iter->left;
Index::left_iterator left_iter = index.left.find(first_left);

    出什么问题了

    auto left_iter = index.left.begin();

  3. 您认为序列化时迭代器的有效性是什么？（参见迭代器失效规则）

    oa << left_iter;

    我认为从存储中加载新的数据结构算作“重新分配”。迭代器或对另一个数据结构的引用显然在这里毫无意义。

  4. 嗯。现在真的越来越混乱了。

    //  first right element of bimap
auto pos = index.left.find(first_left);
Index::right_iterator right_iter = index.right.find(pos->second);

    你称它为“第一个右边元素”，但你做了一些其他的事情：你找到对应于first_left键的迭代器（它很可能是右边的最后一个元素。还要注意，由于 bimap 的右手边是multiset_of，所以可能是多个匹配项，您随机使用第一个匹配项。

    （旁注：pos是left_iter' 值的无用重复）

  5. 见 3。

    oa << right_iter;

  6. 变异：

    • 确保将文件作为二进制文件打开

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

    • 你为什么用 value-semantics 命名一个容器index_reference？这只是不必要的混乱

    • SerializableType未使用
    • BOOST_SERIALIZATION_NVP对二进制档案没有意义（节点在那些档案中没有名称）

真正的问题

我想，真正的问题可能是“我如何序列化Bitsets？”。我很高兴地通知您，我在 2015 年编写了所需的位：如何序列化 boost::dynamic_bitset？并且从版本 1.64 开始，拉取请求已被 Boost 接受。

所以，你可以坐下来，喝茶，包括：

#include <boost/dynamic_bitset/serialization.hpp>

全部完成。

奖金部分

既然该序列化实现了最小副本序列化，为什么不使用它来支持散列函数呢？序列化机制将为您提供所需的私有访问。

我以前滥用序列化管道进行hash<>专业化：散列任意精度值（boost::multiprecision::cpp_int）

把它们放在一起

Live On Coliru

#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;
    }
}

印刷

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

没问题。

后脚本

真的，省去自己的麻烦。由于您的用法清楚地表明您不想要无序的语义，因此只需使其有序：

Live On Coliru

#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;
    }
}

减少到 36 行，剩下不到一半的代码。

于 2017-11-29T00:33:31.710 回答