boost序列化和双精度 [英] boost serialization and doubles

问题描述

我试图使用boost序列化库将一个类序列化为一个字符串，并包含在我的类中是几个双重成员变量。

I am trying to serialize a class to a string using the boost serialization library and included in my class are several double member variables.

m使用序列化：

#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/string.hpp>

std::stringstream ss;
boost::archive::text_oarchive oa(ss);
oa << mPoint;

这是我的Point类中的序列化方法：

Here is the serialiation method within my Point class:

friend class boost::serialization::access;

template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
    if (version > 0)
    {
        ar & mLatitude;
        ar & mLongitude;
    }
}

当我序列化到字符串时，boost不会看起来像我预期的那样处理双到字符串转换（似乎存在四舍五入问题）。研究有点像其他人报告相同的行为。我也理解与将double转换为字符串相反的精度相关问题，反之亦然，以及如何导致问题。

When I serialize to a string, boost doesn't appear to handle the double to string conversion as I would expect (there appear to be rounding issues). Researching a bit it looks like others have reported the same behavior. I also understand the precision related issues associated with converting a double to a string and vice versa and how this could cause the issue.

奇怪的是，我不明白这是不是似乎发生，当我使用一个字符串流本身和重定向double到流，我使用boost的lexical_cast函数将stringstream.str（）转换回double。在发现boost之前有自己的序列化/反序列化类，我实际上写了自己的使用stringstream和lexical_cast调用，它工作w / o问题。我真的希望我不必放弃序列化库，回到我以前的。希望有只是一些设置/ trait /等。

What is strange and I don't understand though is this doesn't appear to happen when I'm using a stringstream itself and redirecting the double to the stream nor when I use boost's lexical_cast function to convert from a stringstream.str() back to a double. Before discovering boost had its own serialization/deserialization classes, I had actually written my own using stringstream and lexical_cast calls and it worked w/o issue. I'm really hoping I don't have to abandon the serialization library and go back to what I had before. Hopefully there is just some setting/trait/etc. I'm missing.

推荐答案

您可以尝试强制您的流在使用科学格式的浮点数之前序列化： p>

You could try forcing your stream to use scientific format for floating point before serialising to it:

ss << std::scientific;

看起来boost库设置的精度正确，但似乎没有设置格式。或者，我可以认为派生和覆盖保存和/或加载浮点数的逻辑，而不会丢弃库的其余部分 - start 这里。

It looks like the boost library sets the precision correctly, but doesn't appear to set the format. Alternatively, you can I think derive and override the logic for saving and/or loading floating point numbers without throwing away the rest of the library - start here.

看起来还有正在进行中支持无限制等。

It also looks like there is work in progress on supporting infinities etc.

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