typedef unsigned short int uint16;
typedef unsigned long int uint32;

// 短整型大小端互換
#define BigLittleSwap16(A)        ((((uint16)(A) & 0xff00) >> 8) | /
                                                   (((uint16)(A) & 0x00ff) << 8))

// 長整型大小端互換
#define BigLittleSwap32(A)        ((((uint32)(A) & 0xff000000) >> 24) | /
                                                   (((uint32)(A) & 0x00ff0000) >> 8) | /
                                                   (((uint32)(A) & 0x0000ff00) << 8) | /
                                                   (((uint32)(A) & 0x000000ff) << 24))

// 本機大端返回1，小端返回0
int checkCPUendian()
{
        union{
                unsigned long int i;
                unsigned char s[4];
        }c = {0x12345678};

        return (0x12 == c.s[0]);
}

// 模擬htonl函式，本機位元組序轉網路位元組序
#define HtoNl(A)        (checkCPUendian() ? (A) : BigLittleSwap32(A))

// 模擬ntohl函式，網路位元組序轉本機位元組序
#define NtoHl(A)        HtoNl(A)

// 模擬htons函式，本機位元組序轉網路位元組序
#define HtoNs(A)        (checkCPUendian() ? (A) : BigLittleSwap16(A))

// 模擬ntohs函式，網路位元組序轉本機位元組序
#define NtoHs(A)        HtoNs(A)