glibc/stdlib/getsubopt.c

80 lines
2.5 KiB
C

/* Parse comma separate list into words.
Copyright (C) 1996-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdlib.h>
#include <string.h>
#if !_LIBC
/* This code is written for inclusion in gnu-libc, and uses names in
the namespace reserved for libc. If we're compiling in gnulib,
define those names to be the normal ones instead. */
# include "strchrnul.h"
# undef __strchrnul
# define __strchrnul strchrnul
#endif
/* Parse comma separated suboption from *OPTIONP and match against
strings in TOKENS. If found return index and set *VALUEP to
optional value introduced by an equal sign. If the suboption is
not part of TOKENS return in *VALUEP beginning of unknown
suboption. On exit *OPTIONP is set to the beginning of the next
token or at the terminating NUL character. */
int
getsubopt (char **optionp, char *const *tokens, char **valuep)
{
char *endp, *vstart;
int cnt;
if (**optionp == '\0')
return -1;
/* Find end of next token. */
endp = __strchrnul (*optionp, ',');
/* Find start of value. */
vstart = memchr (*optionp, '=', endp - *optionp);
if (vstart == NULL)
vstart = endp;
/* Try to match the characters between *OPTIONP and VSTART against
one of the TOKENS. */
for (cnt = 0; tokens[cnt] != NULL; ++cnt)
if (strncmp (*optionp, tokens[cnt], vstart - *optionp) == 0
&& tokens[cnt][vstart - *optionp] == '\0')
{
/* We found the current option in TOKENS. */
*valuep = vstart != endp ? vstart + 1 : NULL;
if (*endp != '\0')
*endp++ = '\0';
*optionp = endp;
return cnt;
}
/* The current suboption does not match any option. */
*valuep = *optionp;
if (*endp != '\0')
*endp++ = '\0';
*optionp = endp;
return -1;
}