/*	$NetBSD: inet_ntop.c,v 1.2 2017/01/28 21:31:50 christos Exp $	*/

/*
 * Copyright (c) 1999 - 2001 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <krb5/roken.h>

/*
 *
 */

static const char *
inet_ntop_v4 (const void *src, char *dst, size_t size)
{
    const char digits[] = "0123456789";
    int i;
    struct in_addr *addr = (struct in_addr *)src;
    u_long a = ntohl(addr->s_addr);
    const char *orig_dst = dst;

    if (size < INET_ADDRSTRLEN) {
	errno = ENOSPC;
	return NULL;
    }
    for (i = 0; i < 4; ++i) {
	int n = (a >> (24 - i * 8)) & 0xFF;
	int non_zerop = 0;

	if (non_zerop || n / 100 > 0) {
	    *dst++ = digits[n / 100];
	    n %= 100;
	    non_zerop = 1;
	}
	if (non_zerop || n / 10 > 0) {
	    *dst++ = digits[n / 10];
	    n %= 10;
	    non_zerop = 1;
	}
	*dst++ = digits[n];
	if (i != 3)
	    *dst++ = '.';
    }
    *dst++ = '\0';
    return orig_dst;
}

#ifdef HAVE_IPV6
static const char *
inet_ntop_v6 (const void *src, char *dst, size_t size)
{
    const char xdigits[] = "0123456789abcdef";
    int i;
    const struct in6_addr *addr = (struct in6_addr *)src;
    const u_char *ptr = addr->s6_addr;
    const char *orig_dst = dst;
    int compressed = 0;

    if (size < INET6_ADDRSTRLEN) {
	errno = ENOSPC;
	return NULL;
    }
    for (i = 0; i < 8; ++i) {
	int non_zerop = 0;

        if (compressed == 0 &&
            ptr[0] == 0 && ptr[1] == 0 &&
            i <= 5 &&
            ptr[2] == 0 && ptr[3] == 0 &&
            ptr[4] == 0 && ptr[5] == 0) {

            compressed = 1;

            if (i == 0)
                *dst++ = ':';
            *dst++ = ':';

            for (ptr += 6, i += 3;
                 i < 8 && ptr[0] == 0 && ptr[1] == 0;
                 ++i, ptr += 2);

            if (i >= 8)
                break;
        }

	if (non_zerop || (ptr[0] >> 4)) {
	    *dst++ = xdigits[ptr[0] >> 4];
	    non_zerop = 1;
	}
	if (non_zerop || (ptr[0] & 0x0F)) {
	    *dst++ = xdigits[ptr[0] & 0x0F];
	    non_zerop = 1;
	}
	if (non_zerop || (ptr[1] >> 4)) {
	    *dst++ = xdigits[ptr[1] >> 4];
	    non_zerop = 1;
	}
	*dst++ = xdigits[ptr[1] & 0x0F];
	if (i != 7)
	    *dst++ = ':';
	ptr += 2;
    }
    *dst++ = '\0';
    return orig_dst;
}
#endif /* HAVE_IPV6 */

ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
inet_ntop(int af, const void *src, char *dst, size_t size)
{
    switch (af) {
    case AF_INET :
	return inet_ntop_v4 (src, dst, size);
#ifdef HAVE_IPV6
    case AF_INET6 :
	return inet_ntop_v6 (src, dst, size);
#endif
    default :
	errno = EAFNOSUPPORT;
	return NULL;
    }
}