stdlib/getsubopt.c

   1 /* Parse comma separate list into words.
   2    Copyright (C) 1996, 1997, 1999, 2004 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 #if !_LIBC
  25 /* This code is written for inclusion in gnu-libc, and uses names in
  26    the namespace reserved for libc.  If we're compiling in gnulib,
  27    define those names to be the normal ones instead.  */
  28 # include "strchrnul.h"
  29 # undef __strchrnul
  30 # define __strchrnul strchrnul
  31 #endif
  32
  33 /* Parse comma separated suboption from *OPTIONP and match against
  34    strings in TOKENS.  If found return index and set *VALUEP to
  35    optional value introduced by an equal sign.  If the suboption is
  36    not part of TOKENS return in *VALUEP beginning of unknown
  37    suboption.  On exit *OPTIONP is set to the beginning of the next
  38    token or at the terminating NUL character.  */
  39 int
  40 getsubopt (char **optionp, char *const *tokens, char **valuep)
  41 {
  42   char *endp, *vstart;
  43   int cnt;
  44
  45   if (**optionp == '\0')
  46     return -1;
  47
  48   /* Find end of next token.  */
  49   endp = __strchrnul (*optionp, ',');
  50
  51   /* Find start of value.  */
  52   vstart = memchr (*optionp, '=', endp - *optionp);
  53   if (vstart == NULL)
  54     vstart = endp;
  55
  56   /* Try to match the characters between *OPTIONP and VSTART against
  57      one of the TOKENS.  */
  58   for (cnt = 0; tokens[cnt] != NULL; ++cnt)
  59     if (strncmp (*optionp, tokens[cnt], vstart - *optionp) == 0
  60         && tokens[cnt][vstart - *optionp] == '\0')
  61       {
  62         /* We found the current option in TOKENS.  */
  63         *valuep = vstart != endp ? vstart + 1 : NULL;
  64
  65         if (*endp != '\0')
  66           *endp++ = '\0';
  67         *optionp = endp;
  68
  69         return cnt;
  70       }
  71
  72   /* The current suboption does not match any option.  */
  73   *valuep = *optionp;
  74
  75   if (*endp != '\0')
  76     *endp++ = '\0';
  77   *optionp = endp;
  78
  79   return -1;
  80 }