/* src/common/port/inet_aton.cpp
 *
 *	This inet_aton() function was taken from the GNU C library and
 *	incorporated into Postgres for those systems which do not have this
 *	routine in their standard C libraries.
 *
 *	The function was been extracted whole from the file inet_aton.c in
 *	Release 5.3.12 of the Linux C library, which is derived from the
 *	GNU C library, by Bryan Henderson in October 1996.	The copyright
 *	notice from that file is below.
 */

/*
 * Copyright (c) 1983, 1990, 1993
 *		The Regents of the University of California.  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 University 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 REGENTS 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 REGENTS 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 "c.h"

#include <netinet/in.h>
#include <ctype.h>

/*
 * Check whether "cp" is a valid ascii representation
 * of an Internet address and convert to a binary address.
 * Returns 1 if the address is valid, 0 if not.
 * This replaces inet_addr, the return value from which
 * cannot distinguish between failure and a local broadcast address.
 */
int inet_aton(const char* cp, struct in_addr* addr)
{
    unsigned int val;
    int base, n;
    char c;
    u_int parts[4];
    u_int* pp = parts;

    for (;;) {
        /*
         * Collect number up to ``.''. Values are specified as for C: 0x=hex,
         * 0=octal, other=decimal.
         */
        val = 0;
        base = 10;
        if (*cp == '0') {
            if (*++cp == 'x' || *cp == 'X') {
                base = 16, cp++;
            } else {
                base = 8;
            }
        }
        while ((c = *cp) != '\0') {
            if (isdigit((unsigned char)c)) {
                val = (val * base) + (c - '0');
                cp++;
                continue;
            }
            if (base == 16 && isxdigit((unsigned char)c)) {
                val = (val << 4) + (c + 10 - (islower((unsigned char)c) ? 'a' : 'A'));
                cp++;
                continue;
            }
            break;
        }
        if (*cp == '.') {
            /*
             * Internet format: a.b.c.d a.b.c	(with c treated as 16-bits)
             * a.b	   (with b treated as 24 bits)
             */
            if (pp >= parts + 3 || val > 0xff) {
                return 0;
            }
            *pp++ = val, cp++;
        } else {
            break;
        }
    }

    /*
     * Check for trailing junk.
     */
    while (*cp) {
        if (!isspace((unsigned char)*cp++)) {
            return 0;
        }
    }

    /*
     * Concoct the address according to the number of parts specified.
     */
    n = pp - parts + 1;
    switch (n) {
        case 1: /* a -- 32 bits */
            break;
        case 2: /* a.b -- 8.24 bits */
            if (val > 0xffffff) {
                return 0;
            }
            val |= parts[0] << 24;
            break;
        case 3: /* a.b.c -- 8.8.16 bits */
            if (val > 0xffff) {
                return 0;
            }
            val |= (parts[0] << 24) | (parts[1] << 16);
            break;
        case 4: /* a.b.c.d -- 8.8.8.8 bits */
            if (val > 0xff) {
                return 0;
            }
            val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
            break;
        default:
            break;
    }
    if (addr != NULL) {
        addr->s_addr = htonl(val);
    }
    return 1;
}