增强序列化和双打
我正在尝试使用 boost 序列化库将类序列化为字符串，并且我的类中包含几个双成员变量。
下面是我用来序列化的代码：
#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：
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
if (version > 0)
{
ar & mLatitude;
ar & mLongitude;
}
}
当我序列化为字符串时，boost 似乎没有按照我的预期处理双精度到字符串转换（似乎有舍入）问题）。经过一番研究，其他人似乎也报告了同样的行为。我还了解与将双精度数转换为字符串相关的精度相关问题，反之亦然，以及这如何导致该问题。
奇怪的是，我不明白的是，当我使用 stringstream 本身并将 double 重定向到流时，或者当我使用 boost 的 lexical_cast 函数从 stringstream.str() 转换回来时，这似乎不会发生到一个双倍。在发现 boost 有自己的序列化/反序列化类之前，我实际上已经使用 stringstream 和 lexical_cast 调用编写了自己的序列化/反序列化类，并且它的工作没有问题。我真的希望我不必放弃序列化库并回到以前的状态。希望只有一些设置/特征/等等。我失踪了。
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.
Below is the code I'm using to serialize:
#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;
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;
}
}
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.
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.
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您可以尝试在序列化流之前强制流使用浮点科学格式：
看起来 boost 库正确设置了精度，但似乎没有设置格式。或者，我可以认为派生并覆盖用于保存和/或加载浮点数的逻辑，而不丢弃库的其余部分 - start 此处。
看起来还有支持无穷大等方面的工作正在进行中 。
You could try forcing your stream to use scientific format for floating point before serialising to it:
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.
It also looks like there is work in progress on supporting infinities etc.
这并不能直接回答
Boost.Serialization问题，而是一种可能的解决方法。从上面的问题来看，我不清楚您是否需要字符串表示形式。如果您正在寻找跨平台表示（二进制或其他形式），请考虑使用 protobuf，它确实支持编码 double 。
http://code.google.com/apis/protocolbuffers/docs/proto .html#标量
This doesn't directly answer the
Boost.Serializationquestion, but is a possible workaround.From the above question, it's not clear to me that you need a string representation or not. If you are looking for a cross-platform representation (binary or otherwise), consider using
protobuf, which does have support for encodingdoubles.http://code.google.com/apis/protocolbuffers/docs/proto.html#scalar