64位网络字节序与主机字节序的转换(linux)

#include "netinet/in.h"
#define UINT64 unsigned long long
#define UINT32 unsigned int

UINT64 ntohUINT64(UINT64 arg64)
{
    UINT64 res64 = 0;
#if __BYTE_ORDER == __LITTLE_ENDIAN
    UINT32 low = (UINT32) (arg64 & 0x00000000FFFFFFFFLL);
    UINT32 high = (UINT32) ((arg64 & 0xFFFFFFFF00000000LL) >> 32);
    low = ntohl(low);
    high = ntohl(high);
    res64 = (UINT64) high + (((UINT64) low) << 32);
#else
    res64 = arg64;
#endif   
    return res64;
}

UINT64 htoUINT64(UINT64 arg64)
{
    UINT64 res64 = 0;
#if __BYTE_ORDER == __LITTLE_ENDIAN   
    UINT32 low = (UINT32) (arg64 & 0x00000000FFFFFFFFLL);
    UINT32 high = (UINT32) ((arg64 & 0xFFFFFFFF00000000LL) >> 32);

    low = htonl(low);
    high = htonl(high);

    res64 = (UINT64) high + (((UINT64) low) << 32);
#else
    res64 = arg64;
#endif   
    return res64;
}