cosmopolitan/libc/sock/inet_ntop.c
2022-09-03 22:46:45 -07:00

104 lines
3.9 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/fmt/itoa.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/errfuns.h"
/**
* Formats internet address to string.
*
* @param af can be AF_INET or AF_INET6
* @param src is the binary-encoded address, e.g. &addr->sin_addr
* @param dst is the output string buffer
* @param size needs to be 16+ for IPv4 and 46+ for IPv6
* @return dst on success or NULL w/ errno
*/
const char *inet_ntop(int af, const void *src, char *dst, uint32_t size) {
char *p;
unsigned char *ip;
int i, t, a, b, c, d;
p = dst;
if (!size) return dst;
if ((ip = src)) {
if (af == AF_INET) {
if (size >= 16) {
p = FormatUint32(p, ip[0]);
*p++ = '.';
p = FormatUint32(p, ip[1]);
*p++ = '.';
p = FormatUint32(p, ip[2]);
*p++ = '.';
p = FormatUint32(p, ip[3]);
*p = '\0';
return dst;
} else {
enospc();
}
} else if (af == AF_INET6) {
if (size >= 46) {
t = 0;
i = 0;
for (i = 0; i < 16; i += 2) {
switch (t) {
case 0:
if (!ip[i] && !ip[i + 1]) {
t = 1;
*p++ = ':';
*p++ = ':';
continue;
} else if (i) {
*p++ = ':';
}
break;
case 1:
if (!ip[i] && !ip[i + 1]) {
continue;
} else {
t = 2;
}
break;
case 2:
*p++ = ':';
break;
default:
unreachable;
}
a = (ip[i + 0] & 0xF0) >> 4;
b = (ip[i + 0] & 0x0F) >> 0;
c = (ip[i + 1] & 0xF0) >> 4;
d = (ip[i + 1] & 0x0F) >> 0;
if (a) *p++ = "0123456789abcdef"[a];
if (a || b) *p++ = "0123456789abcdef"[b];
if (a || b || c) *p++ = "0123456789abcdef"[c];
*p++ = "0123456789abcdef"[d];
}
*p = '\0';
return dst;
} else {
enospc();
}
} else {
eafnosupport();
}
} else {
einval();
}
return 0;
}