29 lines
1.2 KiB
C
29 lines
1.2 KiB
C
/* ************************************************************************** */
|
|
/* */
|
|
/* ::: :::::::: */
|
|
/* cksum.c :+: :+: :+: */
|
|
/* +:+ +:+ +:+ */
|
|
/* By: jhalford <jack@crans.org> +#+ +:+ +#+ */
|
|
/* +#+#+#+#+#+ +#+ */
|
|
/* Created: 2017/10/08 12:45:43 by jhalford #+# #+# */
|
|
/* Updated: 2017/10/08 12:48:41 by jhalford ### ########.fr */
|
|
/* */
|
|
/* ************************************************************************** */
|
|
|
|
unsigned short cksum(void *b, int len)
|
|
{
|
|
unsigned short *buf;
|
|
unsigned int sum;
|
|
|
|
buf = b;
|
|
sum = 0;
|
|
while (len > 1)
|
|
{
|
|
sum += *((unsigned short*)buf++);
|
|
len -= 2;
|
|
}
|
|
if (len == 1)
|
|
sum += *(unsigned char*)buf;
|
|
sum = (sum >> 16) + (sum & 0xFFFF);
|
|
return (~(sum + (sum >> 16)));
|
|
}
|