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/* Hierarchial argument parsing, layered over getopt

   Copyright (C) 1995 Free Software Foundation, Inc.

   Written by Miles Bader <miles@gnu.ai.mit.edu>

   This file is part of the GNU Hurd.

   The GNU Hurd 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 2, or (at
   your option) any later version.

   The GNU Hurd 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#ifndef __ARGP_H__
#define __ARGP_H__

#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <getopt.h>

struct argp_option
{
  /* The long option name.  For more than one name for the same option, you
     can use following options with the OPTION_ALIAS flag set.  */
  char *name;

  /* What key is returned for this option.  If ascii and > 0, then it's also
     accepted as a short option.  */
  int key;

  /* If non-NULL, this is the name of the argument associated with this
     option, which is required unless the OPTION_ARG_OPTIONAL flags is set. */
  char *arg;

  /* ARGP_OPTION_ flags.  */
  int flags;

  /* The doc string for this option.  */
  char *doc;
};

/* The argument associated with this option is optional.  */
#define OPTION_ARG_OPTIONAL	0x1
/* This option isn't displayed in any help messages.  */
#define OPTION_HIDDEN	       	0x2
/* This option is an alias for the closest previous non-alias option.  This
   means that it will be displayed in the same help entry, and will inherit
   fields other than NAME and KEY from the aliased option.  */
#define OPTION_ALIAS		0x4

struct argp;			/* fwd declare this type */
struct argp_state;		/* " */

/* The type of a pointer to an argp parsing function.  */
typedef error_t (*argp_parser_t)(int key, char *arg, struct argp_state *state);

/* Special values for the KEY argument to an argument parsing function.
   EINVAL should be returned if they aren't understood.  */
/* This is not an option at all, but rather a command line argument.  */
#define ARGP_KEY_ARG		0
/* There are no more command line arguments at all.  */
#define ARGP_KEY_END		1

/* An argp structure contains a set of getopt options declarations, a
   function to deal with getting one, and an optional pointer to another
   argp structure.  When actually parsing options, getopt is called with
   the union of all the argp structures chained together through their
   PARENT pointers, with conflicts being resolved in favor of the first
   occurance in the chain.  */
struct argp
{
  /* An array of argp_option structures, terminated by an entry with both
     NAME and KEY having a value of 0.  */
  struct argp_option *options;

  /* What to do with an option from this structure.  KEY is the key
     associated with the option, and ARG is any associated argument (NULL if
     none was supplied).  If KEY isn't understood, EINVAL should be
     returned.  If a non-zero, non-EINVAL value is returned, then parsing is
     stopped immediately, and that value is returned from argp_parse().
     For special (non-user-supplied) values of KEY, see the ARGP_KEY_
     definitions below.  */
  argp_parser_t parser;

  /* A string describing what other arguments are wanted by this program.  It
     is only used by argp_usage to print the `Usage:' message.  */
  char *args_doc;

  /* A string containing extra text to be printed after the options in a long
     help message, if it is non-NULL.  */
  char *doc;

  /* A NULL terminated list of other argp structures that should be parsed
     with this one.  Any conflicts are resolved in favor of this argp, or
     early argps in the PARENTS list.  This field is useful if you use
     libraries that supply their own argp structure, which you want to use in
     conjunction with your own.  */
  struct argp **parents;
};

/* Parsing state.  This is provided to parsing functions called by argp,
   which may examine and, as noted, modify fields.  */
struct argp_state
{
  /* The top level ARGP being parsed.  */
  struct argp *argp;

  /* The argument vector being parsed.  May be modified.  */
  int argc;
  char **argv;

  /* The current index into ARGV.  May be modified.  */
  int index;

  /* The flags supplied to argp_parse.  May be modified.  */
  unsigned flags;
};

/* Flags for argp_parse (note that the defaults are those that are
   convenient for program command line parsing): */

/* Don't ignore the first element of ARGV.  Normally (and always unless
   ARGP_NO_ERRS is set) the first element of the argument vector is
   skipped for option parsing purposes, as it corresponds to the program name
   in a command line.  */
#define ARGP_PARSE_ARGV0    0x1

/* Don't print error messages for unknown options to stderr; unless this flag
   is set, ARGP_PARSE_ARGV0 is ignored, as ARGV[0] is used as the program
   name in the error messages.  */
#define ARGP_NO_ERRS   0x2

/* Don't parse any non-option args.  Normally non-option args are parsed by
   calling the parse functions with a key of ARGP_KEY_ARG, and the actual
   arg as the value.  Since it's impossible to know which parse function
   wants to handle it, each one is called in turn, until one returns 0 or an
   error other than EINVAL; if an argument is handled by no one, the
   argp_parse returns prematurely (but with a return value of 0).  If
   all args have been parsed without error, all parsing functions are called
   one last time with a key of ARGP_KEY_END.  This flag needn't normally
   be set, as the normal behavior is to stop parsing as soon as some argument
   can't be handled.  */
#define ARGP_NO_ARGS   0x4

/* Parse options and arguments in the same order they occur on the command
   line -- normally they're rearranged so that all options come first. */
#define ARGP_IN_ORDER  0x8

/* Don't provide the following standard help behavior:
    o A long option --help is automatically added, which causes usage and
      option help information to be output to stdout, and exit (0) called.
    o Any option parsing errors will result in a short `Try --help' message
      to be output to stderr and exit (1) called.  */
#define ARGP_NO_HELP   0x16

/* Disables the exiting behavior of the above default argp help messages. */
#define ARGP_NO_EXIT   0x32

/* Turns off any message-printing/exiting options.  */
#define ARGP_SILENT    (ARGP_NO_ERRS | ARGP_NO_HELP)

/* Parse the options strings in ARGC & ARGV according to the options in
   ARGP.  FLAGS is one of the ARGP_ flags above.  If ARG_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.  This function may also call exit unless the ARGP_NO_HELP
   flag is set.  */
error_t argp_parse (struct argp *argp, int argc, char **argv, unsigned flags,
		    int *arg_index);

/* Flags for argp_usage:  */
#define ARGP_USAGE_USAGE	0x01 /* Print a Usage: message. */
#define ARGP_USAGE_SEE		0x02 /* Print a `for more help...' message. */
#define ARGP_USAGE_HELP		0x04 /* Print a long help message. */
#define ARGP_USAGE_EXIT_ERR	0x08 /* Call exit(1) instead of returning.  */
#define ARGP_USAGE_EXIT_OK	0x10 /* Call exit(0) instead of returning.  */

/* The standard thing to do after a program command line parsing error.  */
#define ARGP_USAGE_STD \
  (ARGP_USAGE_USAGE | ARGP_USAGE_SEE | ARGP_USAGE_EXIT_ERR)
/* The standard thing to do in response to a --help option.  */
#define ARGP_USAGE_STD_HELP \
  (ARGP_USAGE_USAGE | ARGP_USAGE_HELP | ARGP_USAGE_EXIT_OK)

/* Output a usage message for ARGP to STREAM.  FLAGS are from the set
   ARGP_USAGE_*.  */
void argp_usage (struct argp *argp, FILE *stream, unsigned flags);

/* Returns true if the option OPT is a valid short option.  */
extern inline int
_option_is_short (struct argp_option *opt)
{
  int key = opt->key;
  return key > 0 && isprint (key);
}

/* Returns true if the option OPT is in fact the last (unused) entry in an
   options array.  */
extern inline int
_option_is_end (struct argp_option *opt)
{
  return !opt->key && !opt->name;
}

#endif /* __ARGP_H__ */