/* Hierarchical argument parsing, layered over getopt
   Copyright (C) 1995-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Written by Miles Bader <miles@gnu.ai.mit.edu>.

   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 <https://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <alloca.h>
#include <stdalign.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <getopt.h>
#include <getopt_int.h>

#ifdef _LIBC
# include <libintl.h>
# undef dgettext
# define dgettext(domain, msgid) \
   __dcgettext (domain, msgid, LC_MESSAGES)
#else
# include "gettext.h"
#endif
#define N_(msgid) msgid

#ifdef _LIBC
# define ARGP_TEXT_DOMAIN "libc"
#else
# ifdef DEFAULT_TEXT_DOMAIN
#  define ARGP_TEXT_DOMAIN DEFAULT_TEXT_DOMAIN
# else
#  define ARGP_TEXT_DOMAIN NULL
# endif
#endif

#include "argp.h"
#include "argp-namefrob.h"

#define alignto(n, d) ((((n) + (d) - 1) / (d)) * (d))

/* Getopt return values.  */
#define KEY_END (-1)            /* The end of the options.  */
#define KEY_ARG 1               /* A non-option argument.  */
#define KEY_ERR '?'             /* An error parsing the options.  */

/* The meta-argument used to prevent any further arguments being interpreted
   as options.  */
#define QUOTE "--"

/* The number of bits we steal in a long-option value for our own use.  */
#define GROUP_BITS CHAR_BIT

/* The number of bits available for the user value.  */
#define USER_BITS ((sizeof ((struct option *)0)->val * CHAR_BIT) - GROUP_BITS)
#define USER_MASK ((1 << USER_BITS) - 1)

/* EZ alias for ARGP_ERR_UNKNOWN.  */
#define EBADKEY ARGP_ERR_UNKNOWN

/* Default options.  */

/* When argp is given the --HANG switch, _ARGP_HANG is set and argp will sleep
   for one second intervals, decrementing _ARGP_HANG until it's zero.  Thus
   you can force the program to continue by attaching a debugger and setting
   it to 0 yourself.  */
static volatile int _argp_hang;

#define OPT_PROGNAME    -2
#define OPT_USAGE       -3
#define OPT_HANG        -4

static const struct argp_option argp_default_options[] =
{
  {"help",        '?',          0, 0,  N_("give this help list"), -1},
  {"usage",       OPT_USAGE,    0, 0,  N_("give a short usage message"), 0},
  {"program-name",OPT_PROGNAME, N_("NAME"), OPTION_HIDDEN,
   N_("set the program name"), 0},
  {"HANG",        OPT_HANG,    N_("SECS"), OPTION_ARG_OPTIONAL | OPTION_HIDDEN,
   N_("hang for SECS seconds (default 3600)"), 0},
  {NULL, 0, 0, 0, NULL, 0}
};

static error_t
argp_default_parser (int key, char *arg, struct argp_state *state)
{
  switch (key)
    {
    case '?':
      __argp_state_help (state, state->out_stream, ARGP_HELP_STD_HELP);
      break;
    case OPT_USAGE:
      __argp_state_help (state, state->out_stream,
                         ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
      break;

    case OPT_PROGNAME:          /* Set the program name.  */
#if defined _LIBC || HAVE_DECL_PROGRAM_INVOCATION_NAME
      program_invocation_name = arg;
#endif
      /* [Note that some systems only have PROGRAM_INVOCATION_SHORT_NAME (aka
         __PROGNAME), in which case, PROGRAM_INVOCATION_NAME is just defined
         to be that, so we have to be a bit careful here.]  */

      /* Update what we use for messages.  */
      state->name = __argp_base_name (arg);

#if defined _LIBC || HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME
      program_invocation_short_name = state->name;
#endif

      if ((state->flags & (ARGP_PARSE_ARGV0 | ARGP_NO_ERRS))
          == ARGP_PARSE_ARGV0)
        /* Update what getopt uses too.  */
        state->argv[0] = arg;

      break;

    case OPT_HANG:
      _argp_hang = atoi (arg ? arg : "3600");
      while (_argp_hang-- > 0)
        __sleep (1);
      break;

    default:
      return EBADKEY;
    }
  return 0;
}

static const struct argp argp_default_argp =
  {argp_default_options, &argp_default_parser, NULL, NULL, NULL, NULL,
   ARGP_TEXT_DOMAIN};


static const struct argp_option argp_version_options[] =
{
  {"version",     'V',          0, 0,  N_("print program version"), -1},
  {NULL, 0, 0, 0, NULL, 0}
};

static error_t
argp_version_parser (int key, char *arg, struct argp_state *state)
{
  switch (key)
    {
    case 'V':
      if (argp_program_version_hook)
        (*argp_program_version_hook) (state->out_stream, state);
      else if (argp_program_version)
        fprintf (state->out_stream, "%s\n", argp_program_version);
      else
        __argp_error (state, "%s",
                      dgettext (ARGP_TEXT_DOMAIN,
                                "(PROGRAM ERROR) No version known!?"));
      if (! (state->flags & ARGP_NO_EXIT))
        exit (0);
      break;
    default:
      return EBADKEY;
    }
  return 0;
}

static const struct argp argp_version_argp =
  {argp_version_options, &argp_version_parser, NULL, NULL, NULL, NULL,
   ARGP_TEXT_DOMAIN};

/* Returns the offset into the getopt long options array LONG_OPTIONS of a
   long option with called NAME, or -1 if none is found.  Passing NULL as
   NAME will return the number of options.  */
static int
find_long_option (struct option *long_options, const char *name)
{
  struct option *l = long_options;
  while (l->name != NULL)
    if (name != NULL && strcmp (l->name, name) == 0)
      return l - long_options;
    else
      l++;
  if (name == NULL)
    return l - long_options;
  else
    return -1;
}


/* The state of a "group" during parsing.  Each group corresponds to a
   particular argp structure from the tree of such descending from the top
   level argp passed to argp_parse.  */
struct group
{
  /* This group's parsing function.  */
  argp_parser_t parser;

  /* Which argp this group is from.  */
  const struct argp *argp;

  /* Points to the point in SHORT_OPTS corresponding to the end of the short
     options for this group.  We use it to determine from which group a
     particular short options is from.  */
  char *short_end;

  /* The number of non-option args successfully handled by this parser.  */
  unsigned args_processed;

  /* This group's parser's parent's group.  */
  struct group *parent;
  unsigned parent_index;        /* And the our position in the parent.   */

  /* These fields are swapped into and out of the state structure when
     calling this group's parser.  */
  void *input, **child_inputs;
  void *hook;
};

/* Call GROUP's parser with KEY and ARG, swapping any group-specific info
   from STATE before calling, and back into state afterwards.  If GROUP has
   no parser, EBADKEY is returned.  */
static error_t
group_parse (struct group *group, struct argp_state *state, int key, char *arg)
{
  if (group->parser)
    {
      error_t err;
      state->hook = group->hook;
      state->input = group->input;
      state->child_inputs = group->child_inputs;
      state->arg_num = group->args_processed;
      err = (*group->parser)(key, arg, state);
      group->hook = state->hook;
      return err;
    }
  else
    return EBADKEY;
}

struct parser
{
  const struct argp *argp;

  /* SHORT_OPTS is the getopt short options string for the union of all the
     groups of options.  */
  char *short_opts;
  /* LONG_OPTS is the array of getop long option structures for the union of
     all the groups of options.  */
  struct option *long_opts;
  /* OPT_DATA is the getopt data used for the re-entrant getopt.  */
  struct _getopt_data opt_data;

  /* States of the various parsing groups.  */
  struct group *groups;
  /* The end of the GROUPS array.  */
  struct group *egroup;
  /* A vector containing storage for the CHILD_INPUTS field in all groups.  */
  void **child_inputs;

  /* True if we think using getopt is still useful; if false, then
     remaining arguments are just passed verbatim with ARGP_KEY_ARG.  This is
     cleared whenever getopt returns KEY_END, but may be set again if the user
     moves the next argument pointer backwards.  */
  int try_getopt;

  /* State block supplied to parsing routines.  */
  struct argp_state state;

  /* Memory used by this parser.  */
  void *storage;
};

/* The next usable entries in the various parser tables being filled in by
   convert_options.  */
struct parser_convert_state
{
  struct parser *parser;
  char *short_end;
  struct option *long_end;
  void **child_inputs_end;
};

/* Converts all options in ARGP (which is put in GROUP) and ancestors
   into getopt options stored in SHORT_OPTS and LONG_OPTS; SHORT_END and
   CVT->LONG_END are the points at which new options are added.  Returns the
   next unused group entry.  CVT holds state used during the conversion.  */
static struct group *
convert_options (const struct argp *argp,
                 struct group *parent, unsigned parent_index,
                 struct group *group, struct parser_convert_state *cvt)
{
  /* REAL is the most recent non-alias value of OPT.  */
  const struct argp_option *real = argp->options;
  const struct argp_child *children = argp->children;

  if (real || argp->parser)
    {
      const struct argp_option *opt;

      if (real)
        for (opt = real; !__option_is_end (opt); opt++)
          {
            if (! (opt->flags & OPTION_ALIAS))
              /* OPT isn't an alias, so we can use values from it.  */
              real = opt;

            if (! (real->flags & OPTION_DOC))
              /* A real option (not just documentation).  */
              {
                if (__option_is_short (opt))
                  /* OPT can be used as a short option.  */
                  {
                    *cvt->short_end++ = opt->key;
                    if (real->arg)
                      {
                        *cvt->short_end++ = ':';
                        if (real->flags & OPTION_ARG_OPTIONAL)
                          *cvt->short_end++ = ':';
                      }
                    *cvt->short_end = '\0'; /* keep 0 terminated */
                  }

                if (opt->name
                    && find_long_option (cvt->parser->long_opts, opt->name) < 0)
                  /* OPT can be used as a long option.  */
                  {
                    cvt->long_end->name = opt->name;
                    cvt->long_end->has_arg =
                      (real->arg
                       ? (real->flags & OPTION_ARG_OPTIONAL
                          ? optional_argument
                          : required_argument)
                       : no_argument);
                    cvt->long_end->flag = 0;
                    /* we add a disambiguating code to all the user's
                       values (which is removed before we actually call
                       the function to parse the value); this means that
                       the user loses use of the high 8 bits in all his
                       values (the sign of the lower bits is preserved
                       however)...  */
                    cvt->long_end->val =
                      ((opt->key ? opt->key : real->key) & USER_MASK)
                      + (((group - cvt->parser->groups) + 1) << USER_BITS);

                    /* Keep the LONG_OPTS list terminated.  */
                    (++cvt->long_end)->name = NULL;
                  }
              }
            }

      group->parser = argp->parser;
      group->argp = argp;
      group->short_end = cvt->short_end;
      group->args_processed = 0;
      group->parent = parent;
      group->parent_index = parent_index;
      group->input = 0;
      group->hook = 0;
      group->child_inputs = 0;

      if (children)
        /* Assign GROUP's CHILD_INPUTS field some space from
           CVT->child_inputs_end.*/
        {
          unsigned num_children = 0;
          while (children[num_children].argp)
            num_children++;
          group->child_inputs = cvt->child_inputs_end;
          cvt->child_inputs_end += num_children;
        }

      parent = group++;
    }
  else
    parent = 0;

  if (children)
    {
      unsigned index = 0;
      while (children->argp)
        group =
          convert_options (children++->argp, parent, index++, group, cvt);
    }

  return group;
}

/* Find the merged set of getopt options, with keys appropriately prefixed. */
static void
parser_convert (struct parser *parser, const struct argp *argp, int flags)
{
  struct parser_convert_state cvt;

  cvt.parser = parser;
  cvt.short_end = parser->short_opts;
  cvt.long_end = parser->long_opts;
  cvt.child_inputs_end = parser->child_inputs;

  if (flags & ARGP_IN_ORDER)
    *cvt.short_end++ = '-';
  else if (flags & ARGP_NO_ARGS)
    *cvt.short_end++ = '+';
  *cvt.short_end = '\0';

  cvt.long_end->name = NULL;

  parser->argp = argp;

  if (argp)
    parser->egroup = convert_options (argp, 0, 0, parser->groups, &cvt);
  else
    parser->egroup = parser->groups; /* No parsers at all! */
}

/* Lengths of various parser fields which we will allocated.  */
struct parser_sizes
{
  size_t short_len;             /* Getopt short options string.  */
  size_t long_len;              /* Getopt long options vector.  */
  size_t num_groups;            /* Group structures we allocate.  */
  size_t num_child_inputs;      /* Child input slots.  */
};

/* For ARGP, increments the NUM_GROUPS field in SZS by the total number of
 argp structures descended from it, and the SHORT_LEN & LONG_LEN fields by
 the maximum lengths of the resulting merged getopt short options string and
 long-options array, respectively.  */
static void
calc_sizes (const struct argp *argp,  struct parser_sizes *szs)
{
  const struct argp_child *child = argp->children;
  const struct argp_option *opt = argp->options;

  if (opt || argp->parser)
    {
      szs->num_groups++;
      if (opt)
        {
          int num_opts = 0;
          while (!__option_is_end (opt++))
            num_opts++;
          szs->short_len += num_opts * 3; /* opt + up to 2 ':'s */
          szs->long_len += num_opts;
        }
    }

  if (child)
    while (child->argp)
      {
        calc_sizes ((child++)->argp, szs);
        szs->num_child_inputs++;
      }
}

/* Initializes PARSER to parse ARGP in a manner described by FLAGS.  */
static error_t
parser_init (struct parser *parser, const struct argp *argp,
             int argc, char **argv, int flags, void *input)
{
  error_t err = 0;
  struct group *group;
  struct parser_sizes szs;
  struct _getopt_data opt_data = _GETOPT_DATA_INITIALIZER;
  char *storage;
  size_t glen, gsum;
  size_t clen, csum;
  size_t llen, lsum;
  size_t slen, ssum;

  szs.short_len = (flags & ARGP_NO_ARGS) ? 0 : 1;
  szs.long_len = 0;
  szs.num_groups = 0;
  szs.num_child_inputs = 0;

  if (argp)
    calc_sizes (argp, &szs);

  /* Lengths of the various bits of storage used by PARSER.  */
  glen = (szs.num_groups + 1) * sizeof (struct group);
  clen = szs.num_child_inputs * sizeof (void *);
  llen = (szs.long_len + 1) * sizeof (struct option);
  slen = szs.short_len + 1;

  /* Sums of previous lengths, properly aligned.  There's no need to
     align gsum, since struct group is aligned at least as strictly as
     void * (since it contains a void * member).  And there's no need
     to align lsum, since struct option is aligned at least as
     strictly as char.  */
  gsum = glen;
  csum = alignto (gsum + clen, alignof (struct option));
  lsum = csum + llen;
  ssum = lsum + slen;

  parser->storage = malloc (ssum);
  if (! parser->storage)
    return ENOMEM;

  storage = parser->storage;
  parser->groups = parser->storage;
  parser->child_inputs = (void **) (storage + gsum);
  parser->long_opts = (struct option *) (storage + csum);
  parser->short_opts = storage + lsum;
  parser->opt_data = opt_data;

  memset (parser->child_inputs, 0, clen);
  parser_convert (parser, argp, flags);

  memset (&parser->state, 0, sizeof (struct argp_state));
  parser->state.root_argp = parser->argp;
  parser->state.argc = argc;
  parser->state.argv = argv;
  parser->state.flags = flags;
  parser->state.err_stream = stderr;
  parser->state.out_stream = stdout;
  parser->state.next = 0;       /* Tell getopt to initialize.  */
  parser->state.pstate = parser;

  parser->try_getopt = 1;

  /* Call each parser for the first time, giving it a chance to propagate
     values to child parsers.  */
  if (parser->groups < parser->egroup)
    parser->groups->input = input;
  for (group = parser->groups;
       group < parser->egroup && (!err || err == EBADKEY);
       group++)
    {
      if (group->parent)
        /* If a child parser, get the initial input value from the parent. */
        group->input = group->parent->child_inputs[group->parent_index];

      if (!group->parser
          && group->argp->children && group->argp->children->argp)
        /* For the special case where no parsing function is supplied for an
           argp, propagate its input to its first child, if any (this just
           makes very simple wrapper argps more convenient).  */
        group->child_inputs[0] = group->input;

      err = group_parse (group, &parser->state, ARGP_KEY_INIT, 0);
    }
  if (err == EBADKEY)
    err = 0;                    /* Some parser didn't understand.  */

  if (err)
    return err;

  if (parser->state.flags & ARGP_NO_ERRS)
    {
      parser->opt_data.opterr = 0;
      if (parser->state.flags & ARGP_PARSE_ARGV0)
        /* getopt always skips ARGV[0], so we have to fake it out.  As long
           as OPTERR is 0, then it shouldn't actually try to access it.  */
        parser->state.argv--, parser->state.argc++;
    }
  else
    parser->opt_data.opterr = 1;        /* Print error messages.  */

  if (parser->state.argv == argv && argv[0])
    /* There's an argv[0]; use it for messages.  */
    parser->state.name = __argp_base_name (argv[0]);
  else
    parser->state.name = __argp_short_program_name ();

  return 0;
}

/* Free any storage consumed by PARSER (but not PARSER itself).  */
static error_t
parser_finalize (struct parser *parser,
                 error_t err, int arg_ebadkey, int *end_index)
{
  struct group *group;

  if (err == EBADKEY && arg_ebadkey)
    /* Suppress errors generated by unparsed arguments.  */
    err = 0;

  if (! err)
    {
      if (parser->state.next == parser->state.argc)
        /* We successfully parsed all arguments!  Call all the parsers again,
           just a few more times... */
        {
          for (group = parser->groups;
               group < parser->egroup && (!err || err==EBADKEY);
               group++)
            if (group->args_processed == 0)
              err = group_parse (group, &parser->state, ARGP_KEY_NO_ARGS, 0);
          for (group = parser->egroup - 1;
               group >= parser->groups && (!err || err==EBADKEY);
               group--)
            err = group_parse (group, &parser->state, ARGP_KEY_END, 0);

          if (err == EBADKEY)
            err = 0;            /* Some parser didn't understand.  */

          /* Tell the user that all arguments are parsed.  */
          if (end_index)
            *end_index = parser->state.next;
        }
      else if (end_index)
        /* Return any remaining arguments to the user.  */
        *end_index = parser->state.next;
      else
        /* No way to return the remaining arguments, they must be bogus. */
        {
          if (!(parser->state.flags & ARGP_NO_ERRS)
              && parser->state.err_stream)
            fprintf (parser->state.err_stream,
                     dgettext (ARGP_TEXT_DOMAIN, "%s: Too many arguments\n"),
                     parser->state.name);
          err = EBADKEY;
        }
    }

  /* Okay, we're all done, with either an error or success; call the parsers
     to indicate which one.  */

  if (err)
    {
      /* Maybe print an error message.  */
      if (err == EBADKEY)
        /* An appropriate message describing what the error was should have
           been printed earlier.  */
        __argp_state_help (&parser->state, parser->state.err_stream,
                           ARGP_HELP_STD_ERR);

      /* Since we didn't exit, give each parser an error indication.  */
      for (group = parser->groups; group < parser->egroup; group++)
        group_parse (group, &parser->state, ARGP_KEY_ERROR, 0);
    }
  else
    /* Notify parsers of success, and propagate back values from parsers.  */
    {
      /* We pass over the groups in reverse order so that child groups are
         given a chance to do there processing before passing back a value to
         the parent.  */
      for (group = parser->egroup - 1
           ; group >= parser->groups && (!err || err == EBADKEY)
           ; group--)
        err = group_parse (group, &parser->state, ARGP_KEY_SUCCESS, 0);
      if (err == EBADKEY)
        err = 0;                /* Some parser didn't understand.  */
    }

  /* Call parsers once more, to do any final cleanup.  Errors are ignored.  */
  for (group = parser->egroup - 1; group >= parser->groups; group--)
    group_parse (group, &parser->state, ARGP_KEY_FINI, 0);

  if (err == EBADKEY)
    err = EINVAL;

  free (parser->storage);

  return err;
}

/* Call the user parsers to parse the non-option argument VAL, at the current
   position, returning any error.  The state NEXT pointer is assumed to have
   been adjusted (by getopt) to point after this argument; this function will
   adjust it correctly to reflect however many args actually end up being
   consumed.  */
static error_t
parser_parse_arg (struct parser *parser, char *val)
{
  /* Save the starting value of NEXT, first adjusting it so that the arg
     we're parsing is again the front of the arg vector.  */
  int index = --parser->state.next;
  error_t err = EBADKEY;
  struct group *group;
  int key = 0;                  /* Which of ARGP_KEY_ARG[S] we used.  */

  /* Try to parse the argument in each parser.  */
  for (group = parser->groups
       ; group < parser->egroup && err == EBADKEY
       ; group++)
    {
      parser->state.next++;     /* For ARGP_KEY_ARG, consume the arg.  */
      key = ARGP_KEY_ARG;
      err = group_parse (group, &parser->state, key, val);

      if (err == EBADKEY)
        /* This parser doesn't like ARGP_KEY_ARG; try ARGP_KEY_ARGS instead. */
        {
          parser->state.next--; /* For ARGP_KEY_ARGS, put back the arg.  */
          key = ARGP_KEY_ARGS;
          err = group_parse (group, &parser->state, key, 0);
        }
    }

  if (! err)
    {
      if (key == ARGP_KEY_ARGS)
        /* The default for ARGP_KEY_ARGS is to assume that if NEXT isn't
           changed by the user, *all* arguments should be considered
           consumed.  */
        parser->state.next = parser->state.argc;

      if (parser->state.next > index)
        /* Remember that we successfully processed a non-option
           argument -- but only if the user hasn't gotten tricky and set
           the clock back.  */
        (--group)->args_processed += (parser->state.next - index);
      else
        /* The user wants to reparse some args, give getopt another try.  */
        parser->try_getopt = 1;
    }

  return err;
}

/* Call the user parsers to parse the option OPT, with argument VAL, at the
   current position, returning any error.  */
static error_t
parser_parse_opt (struct parser *parser, int opt, char *val)
{
  /* The group key encoded in the high bits; 0 for short opts or
     group_number + 1 for long opts.  */
  int group_key = opt >> USER_BITS;
  error_t err = EBADKEY;

  if (group_key == 0)
    /* A short option.  By comparing OPT's position in SHORT_OPTS to the
       various starting positions in each group's SHORT_END field, we can
       determine which group OPT came from.  */
    {
      struct group *group;
      char *short_index = strchr (parser->short_opts, opt);

      if (short_index)
        for (group = parser->groups; group < parser->egroup; group++)
          if (group->short_end > short_index)
            {
              err = group_parse (group, &parser->state, opt,
                                 parser->opt_data.optarg);
              break;
            }
    }
  else
    /* A long option.  Preserve the sign in the user key, without
       invoking undefined behavior.  Assume two's complement.  */
    {
      int user_key =
        ((opt & (1 << (USER_BITS - 1))) ? ~USER_MASK : 0) | (opt & USER_MASK);
      err =
        group_parse (&parser->groups[group_key - 1], &parser->state,
                     user_key, parser->opt_data.optarg);
    }

  if (err == EBADKEY)
    /* At least currently, an option not recognized is an error in the
       parser, because we pre-compute which parser is supposed to deal
       with each option.  */
    {
      static const char bad_key_err[] =
        N_("(PROGRAM ERROR) Option should have been recognized!?");
      if (group_key == 0)
        __argp_error (&parser->state, "-%c: %s", opt,
                      dgettext (ARGP_TEXT_DOMAIN, bad_key_err));
      else
        {
          struct option *long_opt = parser->long_opts;
          while (long_opt->val != opt && long_opt->name)
            long_opt++;
          __argp_error (&parser->state, "--%s: %s",
                        long_opt->name ? long_opt->name : "???",
                        dgettext (ARGP_TEXT_DOMAIN, bad_key_err));
        }
    }

  return err;
}

/* Parse the next argument in PARSER (as indicated by PARSER->state.next).
   Any error from the parsers is returned, and *ARGP_EBADKEY indicates
   whether a value of EBADKEY is due to an unrecognized argument (which is
   generally not fatal).  */
static error_t
parser_parse_next (struct parser *parser, int *arg_ebadkey)
{
  int opt;
  error_t err = 0;

  if (parser->state.quoted && parser->state.next < parser->state.quoted)
    /* The next argument pointer has been moved to before the quoted
       region, so pretend we never saw the quoting "--", and give getopt
       another chance.  If the user hasn't removed it, getopt will just
       process it again.  */
    parser->state.quoted = 0;

  if (parser->try_getopt && !parser->state.quoted)
    /* Give getopt a chance to parse this.  */
    {
      /* Put it back in OPTIND for getopt.  */
      parser->opt_data.optind = parser->state.next;
      /* Distinguish KEY_ERR from a real option.  */
      parser->opt_data.optopt = KEY_END;
      if (parser->state.flags & ARGP_LONG_ONLY)
        opt = _getopt_long_only_r (parser->state.argc, parser->state.argv,
                                   parser->short_opts, parser->long_opts, 0,
                                   &parser->opt_data);
      else
        opt = _getopt_long_r (parser->state.argc, parser->state.argv,
                              parser->short_opts, parser->long_opts, 0,
                              &parser->opt_data);
      /* And see what getopt did.  */
      parser->state.next = parser->opt_data.optind;

      if (opt == KEY_END)
        /* Getopt says there are no more options, so stop using
           getopt; we'll continue if necessary on our own.  */
        {
          parser->try_getopt = 0;
          if (parser->state.next > 1
              && strcmp (parser->state.argv[parser->state.next - 1], QUOTE)
                   == 0)
            /* Not only is this the end of the options, but it's a
               "quoted" region, which may have args that *look* like
               options, so we definitely shouldn't try to use getopt past
               here, whatever happens.  */
            parser->state.quoted = parser->state.next;
        }
      else if (opt == KEY_ERR && parser->opt_data.optopt != KEY_END)
        /* KEY_ERR can have the same value as a valid user short
           option, but in the case of a real error, getopt sets OPTOPT
           to the offending character, which can never be KEY_END.  */
        {
          *arg_ebadkey = 0;
          return EBADKEY;
        }
    }
  else
    opt = KEY_END;

  if (opt == KEY_END)
    {
      /* We're past what getopt considers the options.  */
      if (parser->state.next >= parser->state.argc
          || (parser->state.flags & ARGP_NO_ARGS))
        /* Indicate that we're done.  */
        {
          *arg_ebadkey = 1;
          return EBADKEY;
        }
      else
        /* A non-option arg; simulate what getopt might have done.  */
        {
          opt = KEY_ARG;
          parser->opt_data.optarg = parser->state.argv[parser->state.next++];
        }
    }

  if (opt == KEY_ARG)
    /* A non-option argument; try each parser in turn.  */
    err = parser_parse_arg (parser, parser->opt_data.optarg);
  else
    err = parser_parse_opt (parser, opt, parser->opt_data.optarg);

  if (err == EBADKEY)
    *arg_ebadkey = (opt == KEY_END || opt == KEY_ARG);

  return err;
}

/* Parse the options strings in ARGC & ARGV according to the argp in ARGP.
   FLAGS is one of the ARGP_ flags above.  If END_INDEX is non-NULL, the
   index in ARGV of the first unparsed option is returned in it.  If an
   unknown option is present, EINVAL is returned; if some parser routine
   returned a non-zero value, it is returned; otherwise 0 is returned.  */
error_t
__argp_parse (const struct argp *argp, int argc, char **argv, unsigned flags,
              int *end_index, void *input)
{
  error_t err;
  struct parser parser;

  /* If true, then err == EBADKEY is a result of a non-option argument failing
     to be parsed (which in some cases isn't actually an error).  */
  int arg_ebadkey = 0;

#ifndef _LIBC
  if (!(flags & ARGP_PARSE_ARGV0))
    {
#if HAVE_DECL_PROGRAM_INVOCATION_NAME
      if (!program_invocation_name)
        program_invocation_name = argv[0];
#endif
#if HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME
      if (!program_invocation_short_name)
        program_invocation_short_name = __argp_base_name (argv[0]);
#endif
    }
#endif

  if (! (flags & ARGP_NO_HELP))
    /* Add our own options.  */
    {
      struct argp_child *child = alloca (4 * sizeof (struct argp_child));
      struct argp *top_argp = alloca (sizeof (struct argp));

      /* TOP_ARGP has no options, it just serves to group the user & default
         argps.  */
      memset (top_argp, 0, sizeof (*top_argp));
      top_argp->children = child;

      memset (child, 0, 4 * sizeof (struct argp_child));

      if (argp)
        (child++)->argp = argp;
      (child++)->argp = &argp_default_argp;
      if (argp_program_version || argp_program_version_hook)
        (child++)->argp = &argp_version_argp;
      child->argp = 0;

      argp = top_argp;
    }

  /* Construct a parser for these arguments.  */
  err = parser_init (&parser, argp, argc, argv, flags, input);

  if (! err)
    /* Parse! */
    {
      while (! err)
        err = parser_parse_next (&parser, &arg_ebadkey);
      err = parser_finalize (&parser, err, arg_ebadkey, end_index);
    }

  return err;
}
#ifdef weak_alias
weak_alias (__argp_parse, argp_parse)
#endif

/* Return the input field for ARGP in the parser corresponding to STATE; used
   by the help routines.  */
void *
__argp_input (const struct argp *argp, const struct argp_state *state)
{
  if (state)
    {
      struct group *group;
      struct parser *parser = state->pstate;

      for (group = parser->groups; group < parser->egroup; group++)
        if (group->argp == argp)
          return group->input;
    }

  return 0;
}
#ifdef weak_alias
weak_alias (__argp_input, _argp_input)
#endif