Add SUSv3 function getsubopt.

1 files changed, 72 insertions, 0 deletions

diff --git a/libc/unistd/getsubopt.c b/libc/unistd/getsubopt.c
new file mode 100644
index 000000000..682eb4bc4
--- /dev/null
+++ b/libc/unistd/getsubopt.c
@@ -0,0 +1,72 @@
+/* Parse comma separate list into words.
+   Copyright (C) 1996, 1997, 1999 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stdlib.h>
+#include <string.h>
+
+extern char *__strchrnul(const char *s, int c);
+
+/* 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 (memcmp (*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;
+}