1  /* Parse comma separate list into words.
       2     Copyright (C) 1996-2023 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, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #include <stdlib.h>
      21  #include <string.h>
      22  
      23  #if !_LIBC
      24  /* This code is written for inclusion in gnu-libc, and uses names in
      25     the namespace reserved for libc.  If we're compiling in gnulib,
      26     define those names to be the normal ones instead.  */
      27  # include "strchrnul.h"
      28  # undef __strchrnul
      29  # define __strchrnul strchrnul
      30  #endif
      31  
      32  /* Parse comma separated suboption from *OPTIONP and match against
      33     strings in TOKENS.  If found return index and set *VALUEP to
      34     optional value introduced by an equal sign.  If the suboption is
      35     not part of TOKENS return in *VALUEP beginning of unknown
      36     suboption.  On exit *OPTIONP is set to the beginning of the next
      37     token or at the terminating NUL character.  */
      38  int
      39  getsubopt (char **optionp, char *const *tokens, char **valuep)
      40  {
      41    char *endp, *vstart;
      42    int cnt;
      43  
      44    if (**optionp == '\0')
      45      return -1;
      46  
      47    /* Find end of next token.  */
      48    endp = __strchrnul (*optionp, ',');
      49  
      50    /* Find start of value.  */
      51    vstart = memchr (*optionp, '=', endp - *optionp);
      52    if (vstart == NULL)
      53      vstart = endp;
      54  
      55    /* Try to match the characters between *OPTIONP and VSTART against
      56       one of the TOKENS.  */
      57    for (cnt = 0; tokens[cnt] != NULL; ++cnt)
      58      if (strncmp (*optionp, tokens[cnt], vstart - *optionp) == 0
      59  	&& tokens[cnt][vstart - *optionp] == '\0')
      60        {
      61  	/* We found the current option in TOKENS.  */
      62  	*valuep = vstart != endp ? vstart + 1 : NULL;
      63  
      64  	if (*endp != '\0')
      65  	  *endp++ = '\0';
      66  	*optionp = endp;
      67  
      68  	return cnt;
      69        }
      70  
      71    /* The current suboption does not match any option.  */
      72    *valuep = *optionp;
      73  
      74    if (*endp != '\0')
      75      *endp++ = '\0';
      76    *optionp = endp;
      77  
      78    return -1;
      79  }