“big-endian”和“little-endian”的三种参考处理方式

     // ============================================= // Class for 16 bit numbers. // ============================================= template <class T> class CBe16 { typedef union { T i; struct { char a,b; } c; } Union16; char a,b; public: // Sets "big-endian" value. void operator ()(T nValue) { Union16 u16; u16.i = nValue; a = u16.c.b; b = u16.c.a; } // Returns "little-endian" value. T operator ()() { Union16 u16; u16.c.b = a; u16.c.a = b; return u16.i; } }; typedef CBe16<short> CBeShort; typedef CBe16<unsigned short> CBeUShort; // ============================================= // Class for 32 bit numbers. // ============================================= template <class T> class CBe32 { typedef union { T i; struct { char a,b,c,d; } c; } Union32; char a,b,c,d; public: // Sets "big-endian" value. void operator ()(T nValue) { Union32 u32; u32.i = nValue; a = u32.c.d; b = u32.c.c; c = u32.c.b; d = u32.c.a; } // Returns "little-endian" value. T operator ()() { Union32 u32; u32.c.d = a; u32.c.c = b; u32.c.b = c; u32.c.a = d; return u32.i; } }; typedef CBe32<int> CBeInt; typedef CBe32<unsigned int> CBeUInt; typedef CBe32<long> CBeLong; typedef CBe32<unsigned long> CBeULong; typedef CBe32<float> CBeFloat; // ============================================= // Class for 64 bit numbers. // ============================================= class CBeDouble { typedef union { double d; struct { char a,b,c,d,e,f,g,h; } c; } Union64; char a,b,c,d,e,f,g,h; public: // Sets "big-endian" value. void operator ()(double dValue) { Union64 u64; u64.d = dValue; a = u64.c.h; b = u64.c.g; c = u64.c.f; d = u64.c.e; e = u64.c.d; f = u64.c.c; g = u64.c.b; h = u64.c.a; } // Returns "little-endian" value. double operator ()() { Union64 u64; u64.c.h = a; u64.c.g = b; u64.c.f = c; u64.c.e = d; u64.c.d = e; u64.c.c = f; u64.c.b = g; u64.c.a = h; return u64.d; } }; 

    typedef unsigned short uint16; typedef unsigned long uint32; //------------------------------------- // Basic swaps //------------------------------------- template <typename T> inline T WordSwapC( T w ) { uint16 temp; temp = ((*((uint16 *)&w) & 0xff00) >> 8); temp |= ((*((uint16 *)&w) & 0x00ff) << 8); return *((T*)&temp); } template <typename T> inline T DWordSwapC( T dw ) { uint32 temp; temp = *((uint32 *)&dw) >> 24; temp |= ((*((uint32 *)&dw) & 0x00FF0000) >> 8); temp |= ((*((uint32 *)&dw) & 0x0000FF00) << 8); temp |= ((*((uint32 *)&dw) & 0x000000FF) << 24); return *((T*)&temp); } 

    //------------------------------------- // Fast swaps //------------------------------------- template <typename T> inline T WordSwapAsm( T w ) { __asm { mov ax, w xchg al, ah } } template <typename T> inline T DWordSwapAsm( T dw ) { __asm { mov eax, dw bswap eax } }