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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* getopt.h - a simple getopt(3) implementation.
*
* Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
* Copyright (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
*/
#ifndef __GETOPT_H
#define __GETOPT_H
/**
* struct getopt_state - Saved state across getopt() calls
*/
struct getopt_state {
/**
* @index: Index of the next unparsed argument of @argv. If getopt() has
* parsed all of @argv, then @index will equal @argc.
*/
int index;
/* private: */
/** @arg_index: Index within the current argument */
int arg_index;
union {
/* public: */
/**
* @opt: Option being parsed when an error occurs. @opt is only
* valid when getopt() returns ``?`` or ``:``.
*/
int opt;
/**
* @arg: The argument to an option, NULL if there is none. @arg
* is only valid when getopt() returns an option character.
*/
char *arg;
/* private: */
};
};
/**
* getopt_init_state() - Initialize a &struct getopt_state
* @gs: The state to initialize
*
* This must be called before using @gs with getopt().
*/
void getopt_init_state(struct getopt_state *gs);
int __getopt(struct getopt_state *gs, int argc, char *const argv[],
const char *optstring, bool silent);
/**
* getopt() - Parse short command-line options
* @gs: Internal state and out-of-band return arguments. This must be
* initialized with getopt_init_context() beforehand.
* @argc: Number of arguments, not including the %NULL terminator
* @argv: Argument list, terminated by %NULL
* @optstring: Option specification, as described below
*
* getopt() parses short options. Short options are single characters. They may
* be followed by a required argument or an optional argument. Arguments to
* options may occur in the same argument as an option (like ``-larg``), or
* in the following argument (like ``-l arg``). An argument containing
* options begins with a ``-``. If an option expects no arguments, then it may
* be immediately followed by another option (like ``ls -alR``).
*
* @optstring is a list of accepted options. If an option is followed by ``:``
* in @optstring, then it expects a mandatory argument. If an option is followed
* by ``::`` in @optstring, it expects an optional argument. @gs.arg points
* to the argument, if one is parsed.
*
* getopt() stops parsing options when it encounters the first non-option
* argument, when it encounters the argument ``--``, or when it runs out of
* arguments. For example, in ``ls -l foo -R``, option parsing will stop when
* getopt() encounters ``foo``, if ``l`` does not expect an argument. However,
* the whole list of arguments would be parsed if ``l`` expects an argument.
*
* An example invocation of getopt() might look like::
*
* char *argv[] = { "program", "-cbx", "-a", "foo", "bar", 0 };
* int opt, argc = ARRAY_SIZE(argv) - 1;
* struct getopt_state gs;
*
* getopt_init_state(&gs);
* while ((opt = getopt(&gs, argc, argv, "a::b:c")) != -1)
* printf("opt = %c, index = %d, arg = \"%s\"\n", opt, gs.index, gs.arg);
* printf("%d argument(s) left\n", argc - gs.index);
*
* and would produce an output of::
*
* opt = c, index = 1, arg = "<NULL>"
* opt = b, index = 2, arg = "x"
* opt = a, index = 4, arg = "foo"
* 1 argument(s) left
*
* For further information, refer to the getopt(3) man page.
*
* Return:
* * An option character if an option is found. @gs.arg is set to the
* argument if there is one, otherwise it is set to ``NULL``.
* * ``-1`` if there are no more options, if a non-option argument is
* encountered, or if an ``--`` argument is encountered.
* * ``'?'`` if we encounter an option not in @optstring. @gs.opt is set to
* the unknown option.
* * ``':'`` if an argument is required, but no argument follows the
* option. @gs.opt is set to the option missing its argument.
*
* @gs.index is always set to the index of the next unparsed argument in @argv.
*/
static inline int getopt(struct getopt_state *gs, int argc,
char *const argv[], const char *optstring)
{
return __getopt(gs, argc, argv, optstring, false);
}
/**
* getopt_silent() - Parse short command-line options silently
* @gs: State
* @argc: Argument count
* @argv: Argument list
* @optstring: Option specification
*
* Same as getopt(), except no error messages are printed.
*/
static inline int getopt_silent(struct getopt_state *gs, int argc,
char *const argv[], const char *optstring)
{
return __getopt(gs, argc, argv, optstring, true);
}
#endif /* __GETOPT_H */
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