/* Parse arguments from a string and prepend them to an argv.

   Copyright (C) 1999-2002, 2006, 2009-2013, 2015-2017 Free Software

   Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation, either version 3 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert <eggert@twinsun.com>.  */

#include <config.h>

#include "prepargs.h"

#include <string.h>

#include <sys/types.h>

#include <xalloc.h>

#include <ctype.h>

/* IN_CTYPE_DOMAIN (C) is nonzero if the unsigned char C can safely be given

   as an argument to <ctype.h> macros like "isspace".  */

#ifdef STDC_HEADERS

# define IN_CTYPE_DOMAIN(c) 1

#else

# define IN_CTYPE_DOMAIN(c) ((c) <= 0177)

#endif

#define ISSPACE(c) (IN_CTYPE_DOMAIN (c) && isspace (c))

/* Find the white-space-separated options specified by OPTIONS, and

   using BUF to store copies of these options, set ARGV[0], ARGV[1],

   etc. to the option copies.  Return the number N of options found.

   Do not set ARGV[N].  If ARGV is zero, do not store ARGV[0] etc.

   Backslash can be used to escape whitespace (and backslashes).  */

static int

prepend_args (char const *options, char *buf, char **argv)

{

  char const *o = options;

  char *b = buf;

  int n = 0;

  for (;;)

    {

      while (ISSPACE ((unsigned char) *o))

	o++;

      if (!*o)

	return n;

      if (argv)

	argv[n] = b;

      n++;

      do

	if ((*b++ = *o++) == '\\' && *o)

	  b[-1] = *o++;

      while (*o && ! ISSPACE ((unsigned char) *o));

      *b++ = '\0';

    }

}

/* Prepend the whitespace-separated options in OPTIONS to the argument

   vector of a main program with argument count *PARGC and argument

   vector *PARGV.  */

void

prepend_default_options (char const *options, int *pargc, char ***pargv)

{

  if (options)

    {

      char *buf = xmalloc (strlen (options) + 1);

      int prepended = prepend_args (options, buf, (char **) 0);

      int argc = *pargc;

      char * const *argv = *pargv;

      char **pp = xmalloc ((prepended + argc + 1) * sizeof *pp);

      *pargc = prepended + argc;

      *pargv = pp;

      *pp++ = *argv++;

      pp += prepend_args (options, buf, pp);

      while ((*pp++ = *argv++))

	continue;

    }

}