1 #include "endian.h"

2

3 #ifdef NO_INET

4 static uint32_t init_once32(uint32_t x);

5 static uint16_t init_once16(uint16_t x);

6

7 static uint16_t swap16(uint16_t x);

8 static uint32_t swap32(uint32_t x);

9 static uint16_t nop16(uint16_t x);

10 static uint32_t nop32(uint32_t x);

11

12 uint16_t (*ntohs)(uint16_t) = init_once16;

13 uint16_t (*htons)(uint16_t) = init_once16;

14 uint32_t (*ntohl)(uint32_t) = init_once32;

15 uint32_t (*htonl)(uint32_t) = init_once32;

16

17 static uint16_t init_once16(uint16_t x)

18 {

19 int be = bigendian();

20 ntohs = be ? nop16 : swap16;

21 htons = be ? nop16 : swap16;

22 return ntohs(x);

23 }

24

25 static uint32_t init_once32(uint32_t x)

26 {

27 int be = bigendian();

28 ntohl = be ? nop32 : swap32;

29 htonl = be ? nop32 : swap32;

30 return ntohl(x);

31 }

32

33 static uint16_t swap16(uint16_t x)

34 {

35 return (x << 8) | (x >> 8);

36 }

37

38 static uint32_t swap32(uint32_t x)

39 {

40 return (x << 24) | (x >> 24) | ((x << 16) & 0xff0000) | ((x >> 16) & 0xff00);

41 }

42

43 static uint16_t nop16(uint16_t x)

44 {

45 return x;

46 }

47

48 static uint32_t nop32(uint32_t x)

49 {

50 return x;

51 }

52 #endif

53

54 int bigendian(void)

55 {

56 static const uint16_t x = 0xaabb;

57 return *(unsigned char*)&x == 0xaa;

58 }