#include <sys/socket.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
const char *inet_ntop(int af, const void *restrict a0, char *restrict s, socklen_t l)
{
const unsigned char *a = a0;
int i, j, max, best;
char buf[100];
switch (af) {
case AF_INET:
if (snprintf(s, l, "%d.%d.%d.%d", a[0],a[1],a[2],a[3]) < l)
return s;
break;
case AF_INET6:
if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\377\377", 12))
snprintf(buf, sizeof buf,
"%x:%x:%x:%x:%x:%x:%x:%x",
256*a[0]+a[1],256*a[2]+a[3],
256*a[4]+a[5],256*a[6]+a[7],
256*a[8]+a[9],256*a[10]+a[11],
256*a[12]+a[13],256*a[14]+a[15]);
else
snprintf(buf, sizeof buf,
"%x:%x:%x:%x:%x:%x:%d.%d.%d.%d",
256*a[0]+a[1],256*a[2]+a[3],
256*a[4]+a[5],256*a[6]+a[7],
256*a[8]+a[9],256*a[10]+a[11],
a[12],a[13],a[14],a[15]);
/* Replace longest /(^0|:)[:0]{2,}/ with "::" */
for (i=best=0, max=2; buf[i]; i++) {
if (i && buf[i] != ':') continue;
j = strspn(buf+i, ":0");
if (j>max) best=i, max=j;
}
if (max>2) {
buf[best] = buf[best+1] = ':';
memmove(buf+best+2, buf+best+max, i-best-max+1);
}
if (strlen(buf) < l) {
strcpy(s, buf);
return s;
}
break;
default:
errno = EAFNOSUPPORT;
return 0;
}
errno = ENOSPC;
return 0;
}
