stdlib/getsubopt.c

   1 /* Parse comma separate list into words.
   2    Copyright (C) 1996, 1997, 1999 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24
  25 /* Parse comma separated suboption from *OPTIONP and match against
  26    strings in TOKENS.  If found return index and set *VALUEP to
  27    optional value introduced by an equal sign.  If the suboption is
  28    not part of TOKENS return in *VALUEP beginning of unknown
  29    suboption.  On exit *OPTIONP is set to the beginning of the next
  30    token or at the terminating NUL character.  */
  31 int
  32 getsubopt (optionp, tokens, valuep)
  33      char **optionp;
  34      char *const *tokens;
  35      char **valuep;
  36 {
  37   char *endp, *vstart;
  38   int cnt;
  39
  40   if (**optionp == '\0')
  41     return -1;
  42
  43   /* Find end of next token.  */
  44   endp = __strchrnul (*optionp, ',');
  45
  46   /* Find start of value.  */
  47   vstart = memchr (*optionp, '=', endp - *optionp);
  48   if (vstart == NULL)
  49     vstart = endp;
  50
  51   /* Try to match the characters between *OPTIONP and VSTART against
  52      one of the TOKENS.  */
  53   for (cnt = 0; tokens[cnt] != NULL; ++cnt)
  54     if (memcmp (*optionp, tokens[cnt], vstart - *optionp) == 0
  55         && tokens[cnt][vstart - *optionp] == '\0')
  56       {
  57         /* We found the current option in TOKENS.  */
  58         *valuep = vstart != endp ? vstart + 1 : NULL;
  59
  60         if (*endp != '\0')
  61           *endp++ = '\0';
  62         *optionp = endp;
  63
  64         return cnt;
  65       }
  66
  67   /* The current suboption does not match any option.  */
  68   *valuep = *optionp;
  69
  70   if (*endp != '\0')
  71     *endp++ = '\0';
  72   *optionp = endp;
  73
  74   return -1;
  75 }