Question

我有兴趣序列化包含boost::bimap的{{1}}，以便我可以保存并在需要时加载回来。我已经尝试过这样做，但是我遇到了很多错误。我和我的代码如下。

boost::dynamic_bitset

我该怎么做？。

EDIT_1：

在// 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; }中显示编译器和链接器设置（因为我在@sehe提供的答案代码中出现了一些错误。）

EDIT_2

在linux终端上使用的命令Eclispse

g++ -std=c++14 -Os -Wall -pedantic -pthread main.cpp -lboost_serialization && ./a.out

编辑3 使用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我收到以下信息

g++ -std=c++14 -Os -Wall -pedantic -pthread main.cpp -lboost_serialization && ldd a.out

Answer 1

哇。您并不是要使用该哈希函数来实现性能。
- 您正在复制每个键/值哈希上的所有块（例如，在查找时，插入时）
- 你更好永远不希望使用协同例程，因为线程本地静态会让你的生活变得悲惨
请参阅下面的奖励部分

为什么这种笨拙的舞蹈（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);

有什么问题

auto left_iter = index.left.begin();

您认为序列化时迭代器的有效性是什么？（见Iterator invalidation rules）
```
oa << left_iter;
```
我认为从存储中加载新的数据结构计为＆＃34;重新分配＆＃34;。迭代器或对另一个数据结构的引用在这里显然毫无意义。
呃。现在它真的让人困惑。
```
//  first right element of bimap
auto pos = index.left.find(first_left);
Index::right_iterator right_iter = index.right.find(pos->second);
```
你称之为＆＃34;第一个正确的元素＆＃34;，但是你做了一些事情：你找到了对应于first_left键的迭代器（它可能是右边的最后一个元素。请注意，由于bimap的右侧是multiset_of，因此可能会有多个匹配，您随机使用第一个。

（旁注：pos是left_iter价值的无用重复）
见3.
```
oa << right_iter;
```
瓦里亚：
- 确保以二进制文件打开文件
```
std::ofstream ofs("binaryfile", std::ios::binary);
std::ifstream ifs("binaryfile", std::ios::binary);
```
- 为什么要为具有值语义index_reference的容器命名？
- SerializableType未使用
- BOOST_SERIALIZATION_NVP对二进制存档没有意义（节点中没有名称）

真实问题

我想，真正的问题可能是＆＃34;如何序列化Bitset？＆＃34;。我很高兴地通知您，我在2015年写了所需的位：How to serialize boost::dynamic_bitset?并且拉取请求已被Boost starting with version 1.64接受。

所以，你可以坐下来，啜饮你的茶，包括：

#include <boost/dynamic_bitset/serialization.hpp>

全部完成。

奖金部分

由于该序列化实现了最小拷贝序列化，为什么不使用它来为哈希函数提供动力？序列化机制将为您提供所需的私人访问权限。

我之前滥用hash<>专精的序列化管道：Hash an arbitrary precision value (boost::multiprecision::cpp_int)

全部放在一起

<强> 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;
    }
}

打印

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

没问题。

POST SCRIPTUM

真的，省去自己的麻烦。由于您的使用清楚地表明您不想要无序语义，因此只需将其命令：

<强> 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;
    }
}

低至36行，不到代码的一半。

使用boost :: dynamic_bitset作为键值对序列化boost :: bimap

1 个答案:

真实问题

奖金部分

全部放在一起

POST SCRIPTUM