inet/ether_aton_r.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <ctype.h>
  21 #include <stdlib.h>
  22 #include <netinet/ether.h>
  23 #include <netinet/if_ether.h>
  24
  25
  26 struct ether_addr *
  27 ether_aton_r (const char *asc, struct ether_addr *addr)
  28 {
  29   size_t cnt;
  30
  31   for (cnt = 0; cnt < 6; ++cnt)
  32     {
  33       unsigned int number;
  34       char ch;
  35
  36       ch = _tolower (*asc++);
  37       if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  38         return NULL;
  39       number = isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  40
  41       ch = _tolower (*asc);
  42       if ((cnt < 5 && ch != ':') || (cnt == 5 && ch != '\0' && !isspace (ch)))
  43         {
  44           ++asc;
  45           if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  46             return NULL;
  47           number <<= 4;
  48           number += isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  49
  50           ch = *asc;
  51           if (cnt < 5 && ch != ':')
  52             return NULL;
  53         }
  54
  55       /* Store result.  */
  56       addr->ether_addr_octet[cnt] = (unsigned char) number;
  57
  58       /* Skip ':'.  */
  59       ++asc;
  60     }
  61
  62   return addr;
  63 }