Big-Endian <-> Little-Endian 互轉

【轉貼】C++ FAQ

轉換的動作是可逆的 (Big-Endian <-> Little-Endian)，下面這個例子可以用來轉換unsigned data types.

inline void endian_swap(unsigned short& x)
{
x = (x>>8) |
    (x<<8);
}

inline void endian_swap(unsigned int& x)
{
x = (x>>24) |
    ((x<<8) & 0x00FF0000) |
    ((x>>8) & 0x0000FF00) |
    (x<<24);
}

// __int64 for MSVC, "long long" for gcc
inline void endian_swap(unsigned __int64& x)
{
x = (x>>56) |
    ((x<<40) & 0x00FF000000000000) |
    ((x<<24) & 0x0000FF0000000000) |
    ((x<<8)  & 0x000000FF00000000) |
    ((x>>8)  & 0x00000000FF000000) |
    ((x>>24) & 0x0000000000FF0000) |
    ((x>>40) & 0x000000000000FF00) |
    (x<<56);
}

【轉貼】C++ FAQ