BSD 4_3 release

[unix-history] / usr / src / lib / libc / inet / inet_addr.c

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)inet_addr.c 5.2 (Berkeley) 3/9/86";
#endif LIBC_SCCS and not lint

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

/*
* Internet address interpretation routine.
* All the network library routines call this
* routine to interpret entries in the data bases
* which are expected to be an address.
* The value returned is in network order.
*/
u_long
inet_addr(cp)
       register char *cp;
{
       register u_long val, base, n;
       register char c;
       u_long parts[4], *pp = parts;

again:
       /*
        * Collect number up to ``.''.
        * Values are specified as for C:
        * 0x=hex, 0=octal, other=decimal.
        */
       val = 0; base = 10;
       if (*cp == '0')
               base = 8, cp++;
       if (*cp == 'x' || *cp == 'X')
               base = 16, cp++;
       while (c = *cp) {
               if (isdigit(c)) {
                       val = (val * base) + (c - '0');
                       cp++;
                       continue;
               }
               if (base == 16 && isxdigit(c)) {
                       val = (val << 4) + (c + 10 - (islower(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 + 4)
                       return (-1);
               *pp++ = val, cp++;
               goto again;
       }
       /*
        * Check for trailing characters.
        */
       if (*cp && !isspace(*cp))
               return (-1);
       *pp++ = val;
       /*
        * Concoct the address according to
        * the number of parts specified.
        */
       n = pp - parts;
       switch (n) {

       case 1:                         /* a -- 32 bits */
               val = parts[0];
               break;

       case 2:                         /* a.b -- 8.24 bits */
               val = (parts[0] << 24) | (parts[1] & 0xffffff);
               break;

       case 3:                         /* a.b.c -- 8.8.16 bits */
               val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
                       (parts[2] & 0xffff);
               break;

       case 4:                         /* a.b.c.d -- 8.8.8.8 bits */
               val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
                     ((parts[2] & 0xff) << 8) | (parts[3] & 0xff);
               break;

       default:
               return (-1);
       }
       val = htonl(val);
       return (val);
}