问增强原始C数组的序列化和反序列化
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Stack Overflow用户

提问于 2013-12-15 08:47:00

回答 2查看 6.3K关注 0票数 7

我正在尝试序列化和反序列化原始C指针及其数据，下面的示例如下所示。它似乎序列化得很好，但我不知道如何使它反序列化--当我反序列化它时，它只会与内存访问冲突异常崩溃。我想是因为它不知道如何反序列化它，但是我应该在哪里指定呢？

使用向量不是一种选择，在非常大的原始数据量中，它速度慢得令人痛苦。

#include <stdint.h>
#include <string>
#include <iostream>
#include <fstream>
#pragma warning (push) 
#pragma warning( disable : 4244 ) 
#include <boost/serialization/serialization.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/string.hpp>
#include <boost/serialization/array.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#pragma warning (pop) 

struct Monkey
{
    uint32_t num;
    float* arr;

};


namespace boost
{
    namespace serialization
    {
        template<class Archive>
        void serialize(Archive & ar, Monkey& m, const unsigned int version)
        {
            ar & m.num;
            ar & make_array<float>(m.arr, m.num);
        }
    }
}


int _tmain(int argc, _TCHAR* argv[])
{
    const char* name = "monkey.txt";

    {
        Monkey m;
        m.num = 10;
        m.arr = new float[m.num];
        for (uint32_t index = 0; index < m.num; index++)
            m.arr[index] = (float)index;

        std::ofstream outStream(name, std::ios::out | std::ios::binary | std::ios::trunc);
        boost::archive::binary_oarchive oar(outStream);
        oar << (m);
    }

    Monkey m;
    std::ifstream inStream(name, std::ios::in | std::ios::binary);     
    boost::archive::binary_iarchive iar(inStream);
    iar >> (m);

    return 0;
}

c++

serialization

boost

boost-serialization

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回答 2

Stack Overflow用户

回答已采纳

发布于 2013-12-15 12:34:29

我衷心建议你在这里使用std::array或std::vector，因为.你搞砸了:)

首先，Monkey不初始化其成员。因此，加载结果是对任何指针值( load_binary )执行m.arr操作。您如何期望反序列化“知道”您需要为此分配内存？你得告诉我

    template<class Archive>
    void serialize(Archive & ar, Monkey& m, const unsigned int version)
    {
        ar & m.num;
        if (Archive::is_loading::value)
        {
            assert(m.arr == nullptr);
            m.arr = new float[m.num];
        }
        ar & make_array<float>(m.arr, m.num);
    }

现在，让我们减少一些Monkey的不安全(通过添加初始化和销毁，也许最重要的是，禁止复制语义)：

struct Monkey
{
    uint32_t num;
    float* arr;

    Monkey() : num(0u), arr(nullptr) {}

    Monkey(Monkey const&) = delete;
    Monkey& operator=(Monkey const&) = delete;
    ~Monkey() { delete[] arr; }
};

现在，你可以看到它起作用了：

#include <iostream>
#include <fstream>
#pragma warning(disable: 4244)
#include <boost/serialization/serialization.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>

struct Monkey
{
    uint32_t num;
    float* arr;

    Monkey() : num(0u), arr(nullptr) {}

    Monkey(Monkey const&) = delete;
    Monkey& operator=(Monkey const&) = delete;
    ~Monkey() { delete[] arr; }
};

namespace boost
{
    namespace serialization
    {
        template<class Archive>
        void serialize(Archive & ar, Monkey& m, const unsigned int version)
        {
            ar & m.num;
            if (Archive::is_loading::value)
            {
                assert(m.arr == nullptr);
                m.arr = new float[m.num];
            }
            ar & make_array<float>(m.arr, m.num);
        }
    }
}

int main(int argc, char* argv[])
{
    const char* name = "monkey.txt";
    {
        Monkey m;
        m.num = 10;
        m.arr = new float[m.num];
        for (uint32_t index = 0; index < m.num; index++)
            m.arr[index] = (float)index;

        std::ofstream outStream(name, std::ios::out | std::ios::binary | std::ios::trunc);
        boost::archive::binary_oarchive oar(outStream);
        oar << (m);
    }

    Monkey m;
    std::ifstream inStream(name, std::ios::in | std::ios::binary);
    boost::archive::binary_iarchive iar(inStream);
    iar >> (m);

    std::copy(m.arr, m.arr + m.num, std::ostream_iterator<float>(std::cout, ";"));
}