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