我可以重载CArchive<<操作符使用std :: string？ [英] Can I overload CArchive << operator to work with std::string?

问题描述

我在我的MFC应用程序中使用std :: string，我想将其存储在doc的Serialize（）函数。我不想将它们存储为CString因为它写入自己的东西在那里，我的目标是创建一个文件，我知道的格式，并可以由其他应用程序读取，而不需要CString。所以我想存储我的std ::字符串为4字节（int）字符串长度，后面是包含该字符串的大小的缓冲区。

I am using std::string in my MFC application and I want to store it in doc's Serialize() function. I don't want to store them as CString because it writes its own stuff in there and my goal is to create a file that I know the format of and can be read by other application without needing CString. So I would like to store my std::strings as 4 bytes (int) string length followed by buffer of that size containing the string.

void CMyDoc::Serialize(CArchive& ar)
{
    std::string theString;

    if (ar.IsStoring())
    {
        // TODO: add storing code here
        int size = theString.size();
        ar << size;
        ar.Write( theString.c_str(), size );

    }
    else
    {
        // TODO: add loading code here
        int size = 0;
        ar >> size;
        char * bfr = new char[ size ];
        ar.Read( bfr, size);
        theString = bfr;
        delete [] bfr;
    }
}

上面的代码不是很好，一个temp bfr来读取字符串。首先我可以读取字符串直接到std :: string没有临时缓冲区？其次，我可以重载<<缓冲区为std :: string / CArchive所以我可以简单地使用ar< theString？总之，有一个更好的方法来读/写std :: string使用CArchive对象？

The above code is not great and I have to allocate a temp bfr to read the string. First can I read the string directly into std::string without the temp buffer? Secondly can I overload the << buffer for std::string / CArchive so I can simply use ar << theString? Overall is there a better way to read/write std::string using CArchive object?

推荐答案

你可以构建一个内部CString你的stl字符串并序列化。例如：

You could build an inplace CString from your stl string and serialize that. Something like:

CString c_string(my_stl_string.c_str();
ar << c_string;

您可以将此放置在全局操作符重载中，以便您可以

You could put this in a global operater overload so it can you can just

ar << my_c_string;

从任何地方，例如：

CArchive& operator<<(CArchive rhs, string lhs) {
    CString c_string(lhs.c_str());
    rhs << c_string;
}

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