跨平台字节序转换

Question

I've written this code to convert between host and network endianness and found the implementations for both directions is the same. Is that right?

template<typename T>
T be_to_host(T val)
{
    T outval = 0;
    std::size_t len = sizeof(T);
    char *data = reinterpret_cast<char*>(&outval);
    // network endian (big) to host endian
    for (int i = 0; i < len; i++)
        data[i] = (val >> ((len - i - 1) * 8)) & 0xFF;

    return outval;
}

template<typename T>
T host_to_be(T val)
{
    // works both ways on any platform
    return be_to_host<T>(val);
}

I've convinced myself this code is OK but I've always seen different implementations for each direction so I can't shake that feeling that I'm missing something. The fact the 'val' is interpreted as host endianness makes this code bi-direction, right?

Thanks

Answer 1

如果字节序不同，那么在任一方向上的任务是颠倒字节的顺序，所以是的，在任一方向上的实现是相同的。