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Annotation of 43BSD/lib/libc/inet/inet_addr.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1983 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  */
                      6: 
                      7: #if defined(LIBC_SCCS) && !defined(lint)
                      8: static char sccsid[] = "@(#)inet_addr.c        5.2 (Berkeley) 3/9/86";
                      9: #endif LIBC_SCCS and not lint
                     10: 
                     11: #include <sys/types.h>
                     12: #include <ctype.h>
                     13: #include <netinet/in.h>
                     14: 
                     15: /*
                     16:  * Internet address interpretation routine.
                     17:  * All the network library routines call this
                     18:  * routine to interpret entries in the data bases
                     19:  * which are expected to be an address.
                     20:  * The value returned is in network order.
                     21:  */
                     22: u_long
                     23: inet_addr(cp)
                     24:        register char *cp;
                     25: {
                     26:        register u_long val, base, n;
                     27:        register char c;
                     28:        u_long parts[4], *pp = parts;
                     29: 
                     30: again:
                     31:        /*
                     32:         * Collect number up to ``.''.
                     33:         * Values are specified as for C:
                     34:         * 0x=hex, 0=octal, other=decimal.
                     35:         */
                     36:        val = 0; base = 10;
                     37:        if (*cp == '0')
                     38:                base = 8, cp++;
                     39:        if (*cp == 'x' || *cp == 'X')
                     40:                base = 16, cp++;
                     41:        while (c = *cp) {
                     42:                if (isdigit(c)) {
                     43:                        val = (val * base) + (c - '0');
                     44:                        cp++;
                     45:                        continue;
                     46:                }
                     47:                if (base == 16 && isxdigit(c)) {
                     48:                        val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A'));
                     49:                        cp++;
                     50:                        continue;
                     51:                }
                     52:                break;
                     53:        }
                     54:        if (*cp == '.') {
                     55:                /*
                     56:                 * Internet format:
                     57:                 *      a.b.c.d
                     58:                 *      a.b.c   (with c treated as 16-bits)
                     59:                 *      a.b     (with b treated as 24 bits)
                     60:                 */
                     61:                if (pp >= parts + 4)
                     62:                        return (-1);
                     63:                *pp++ = val, cp++;
                     64:                goto again;
                     65:        }
                     66:        /*
                     67:         * Check for trailing characters.
                     68:         */
                     69:        if (*cp && !isspace(*cp))
                     70:                return (-1);
                     71:        *pp++ = val;
                     72:        /*
                     73:         * Concoct the address according to
                     74:         * the number of parts specified.
                     75:         */
                     76:        n = pp - parts;
                     77:        switch (n) {
                     78: 
                     79:        case 1:                         /* a -- 32 bits */
                     80:                val = parts[0];
                     81:                break;
                     82: 
                     83:        case 2:                         /* a.b -- 8.24 bits */
                     84:                val = (parts[0] << 24) | (parts[1] & 0xffffff);
                     85:                break;
                     86: 
                     87:        case 3:                         /* a.b.c -- 8.8.16 bits */
                     88:                val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
                     89:                        (parts[2] & 0xffff);
                     90:                break;
                     91: 
                     92:        case 4:                         /* a.b.c.d -- 8.8.8.8 bits */
                     93:                val = (parts[0] << 24) | ((parts[1] & 0xff) << 16) |
                     94:                      ((parts[2] & 0xff) << 8) | (parts[3] & 0xff);
                     95:                break;
                     96: 
                     97:        default:
                     98:                return (-1);
                     99:        }
                    100:        val = htonl(val);
                    101:        return (val);
                    102: }

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