[unix-history] / usr / src / lib / libc / net / inet_network.c

/*      @(#)inet_network.c      4.1     %G%     */

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

/*
* Internet network address interpretation routine.
* The library routines call this routine to interpret
* network numbers.
*/
u_long
inet_network(cp)
       register char *cp;
{
       register u_long val, base, n;
       register char c;
       u_long parts[4], *pp = parts;

again:
       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 == '.') {
               if (pp >= parts + 4)
                       return (-1);
               *pp++ = val, cp++;
               goto again;
       }
       if (*cp && !isspace(*cp))
               return (-1);
       *pp++ = val;
       n = pp - parts;
       if (n > 4)
               return (-1);
       for (val = 0, i = 0; i < n; i++) {
               val <<= 8;
               val |= parts[i] & 0xff;
       }
       return (val);
}