/*-
 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#ifdef _WIN32
#include <windows.h>
typedef unsigned long in_addr_t;
#endif
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
#ifndef _WIN32
#include <netinet/in.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif

int
inet_aton(const char *cp, struct in_addr *addr)
{
    u_long parts[4];
    in_addr_t val;
    const char *c;
    char *endptr;
    int gotend, n;

    c = (const char *)cp;
    n = 0;

    /*
     * Run through the string, grabbing numbers until
     * the end of the string, or some error
     */
    gotend = 0;
    while (!gotend) {
        unsigned long l;

        l = strtoul(c, &endptr, 0);

        if (l == ULONG_MAX || (l == 0 && endptr == c))
            return (0);

        val = (in_addr_t)l;

        /*
         * If the whole string is invalid, endptr will equal
         * c.. this way we can make sure someone hasn't
         * gone '.12' or something which would get past
         * the next check.
         */
        if (endptr == c)
            return (0);
        parts[n] = val;
        c = endptr;

        /* Check the next character past the previous number's end */
        switch (*c) {
        case '.' :

            /* Make sure we only do 3 dots .. */
            if (n == 3) /* Whoops. Quit. */
                return (0);
            n++;
            c++;
            break;

        case '\0':
            gotend = 1;
            break;

        default:
            if (isspace((unsigned char)*c)) {
                gotend = 1;
                break;
            } else {

                /* Invalid character, then fail. */
                return (0);
            }
        }

    }

    /* Concoct the address according to the number of parts specified. */
    switch (n) {
    case 0:             /* a -- 32 bits */

        /*
         * Nothing is necessary here.  Overflow checking was
         * already done in strtoul().
         */
        break;
    case 1:             /* a.b -- 8.24 bits */
        if (val > 0xffffff || parts[0] > 0xff)
            return (0);
        val |= parts[0] << 24;
        break;

    case 2:             /* a.b.c -- 8.8.16 bits */
        if (val > 0xffff || parts[0] > 0xff || parts[1] > 0xff)
            return (0);
        val |= (parts[0] << 24) | (parts[1] << 16);
        break;

    case 3:             /* a.b.c.d -- 8.8.8.8 bits */
        if (val > 0xff || parts[0] > 0xff || parts[1] > 0xff ||
            parts[2] > 0xff)
            return (0);
        val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
        break;
    }

    if (addr != NULL)
        addr->s_addr = htonl(val);
    return (1);
}

#ifdef __cplusplus
}
#endif
