getopt.c

/* getopt.c
Copyright (C) 1989, 1990, 1991,	1992, 1993 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 2,	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, write to the Free Software
Foundation,	675	Mass Ave, Cambridge, MA	02139, USA.	 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "getopt.h"

/* For communication from `getopt' to the caller.
When `getopt' finds	an option that takes an	argument,
the	argument value is returned here.
Also, when `ordering' is RETURN_IN_ORDER,
each non-option	ARGV-element is	returned here.	*/

char *optarg = 0;

/* Index in	ARGV of	the	next element to	be scanned.
This is	used for communication to and from the caller
and	for	communication between successive calls to `getopt'.

On entry to	`getopt', zero means this is the first call; initialize.

When `getopt' returns EOF, this	is the index of	the	first of the
non-option elements	that the caller	should itself scan.

Otherwise, `optind'	communicates from one call to the next
how	much of	ARGV has been scanned so far.  */

/* XXX 1003.2 says this	must be	1 before any call.	*/
int	optind = 0;

/* The next	char to	be scanned in the option-element
in which the last option character we returned was found.
This allows	us to pick up the scan where we	left off.

If this	is zero, or	a null string, it means	resume the scan
by advancing to	the	next ARGV-element.	*/

static char	*nextchar;

/* Callers store zero here to inhibit the error	message
for	unrecognized options.  */

int	opterr = 1;

/* Set to an option	character which	was	unrecognized.
This must be initialized on	some systems to	avoid linking in the
system's own getopt	implementation.	 */

#define	BAD_OPTION '\0'
int	optopt = BAD_OPTION;

/* Describe	how	to deal	with options that follow non-option	ARGV-elements.

If the caller did not specify anything,
the	default	is REQUIRE_ORDER if	the	environment	variable
POSIXLY_CORRECT	is defined,	PERMUTE	otherwise.

REQUIRE_ORDER means	don't recognize	them as	options;
stop option	processing when	the	first non-option is	seen.
This is	what Unix does.
This mode of operation is selected by either setting the environment
variable POSIXLY_CORRECT, or using `+' as the first	character
of the list	of option characters.

PERMUTE	is the default.	 We	permute	the	contents of	ARGV as	we scan,
so that	eventually all the non-options are at the end.	This allows	options
to be given	in any order, even with	programs that were not written to
expect this.

RETURN_IN_ORDER	is an option available to programs that	were written
to expect options and other	ARGV-elements in any order and that	care about
the	ordering of	the	two.  We describe each non-option ARGV-element
as if it were the argument of an option	with character code	1.
Using `-' as the first character of	the	list of	option characters
selects	this mode of operation.

The	special	argument `--' forces an	end	of option-scanning regardless
of the value of	`ordering'.	 In	the	case of	RETURN_IN_ORDER, only
`--' can cause `getopt'	to return EOF with `optind'	!= ARGC.  */

static enum
{
	REQUIRE_ORDER, PERMUTE,	RETURN_IN_ORDER
} ordering;

/* Avoid depending on library functions	or files
whose names	are	inconsistent.  */

#if	__STDC__ ||	defined(PROTO)
extern char	*getenv(const char *name);
extern int	strcmp (const char *s1,	const char *s2);
extern int	strncmp(const char *s1,	const char *s2,	size_t	n);

static int my_strlen(const char	*s);
static char	*my_index (const char *str,	int	chr);
#else
extern char	*getenv	();
#endif

static int
my_strlen (const char	*str)
{
	int	n =	0;
	while (*str++)
		n++;
	return n;
}

static char	*
my_index (const	char *str, int chr)
{
	while (*str)
	{
		if (*str ==	chr)
			return (char *)	str;
		str++;
	}
	return 0;
}



/* Handle permutation of arguments.	 */

/* Describe	the	part of	ARGV that contains non-options that	have
been skipped.  `first_nonopt' is the index in ARGV of the first	of them;
`last_nonopt' is the index after the last of them.	*/

static int first_nonopt;
static int last_nonopt;

/* Exchange	two	adjacent subsequences of ARGV.
One	subsequence	is elements	[first_nonopt,last_nonopt)
which contains all the non-options that	have been skipped so far.
The	other is elements [last_nonopt,optind),	which contains all
the	options	processed since	those non-options were skipped.

`first_nonopt' and `last_nonopt' are relocated so that they	describe
the	new	indices	of the non-options in ARGV after they are moved.

To perform the swap, we	first reverse the order	of all elements. So
all	options	now	come before	all	non	options, but they are in the
wrong order. So	we put back	the	options	and	non	options	in original
order by reversing them	again. For example:
original input:		 a b c -x -y
reverse	all:		 -y	-x c b a
reverse	options:	 -x	-y c b a
reverse	non	options: -x	-y a b c
*/

#if	__STDC__ ||	defined(PROTO)
static void	exchange (char **argv);
#endif

static void
exchange (char **argv)
{
	char *temp,	**first, **last;

	/* Reverse all the elements	[first_nonopt, optind) */
	first =	&argv[first_nonopt];
	last  =	&argv[optind-1];
	while (first < last) {
		temp = *first; *first =	*last; *last = temp; first++; last--;
	}
	/* Put back	the	options	in order */
	first =	&argv[first_nonopt];
	first_nonopt +=	(optind	- last_nonopt);
	last  =	&argv[first_nonopt - 1];
	while (first < last) {
		temp = *first; *first =	*last; *last = temp; first++; last--;
	}

	/* Put back	the	non	options	in order */
	first =	&argv[first_nonopt];
	last_nonopt	= optind;
	last  =	&argv[last_nonopt-1];
	while (first < last) {
		temp = *first; *first =	*last; *last = temp; first++; last--;
	}
}

/* Scan	elements of	ARGV (whose	length is ARGC)	for	option characters
given in OPTSTRING.

If an element of ARGV starts with '-', and is not exactly "-" or "--",
then it	is an option element.  The characters of this element
(aside from	the	initial	'-') are option	characters.	 If	`getopt'
is called repeatedly, it returns successively each of the option characters
from each of the option	elements.

If `getopt'	finds another option character,	it returns that	character,
updating `optind' and `nextchar' so	that the next call to `getopt' can
resume the scan	with the following option character	or ARGV-element.

If there are no	more option	characters,	`getopt' returns `EOF'.
Then `optind' is the index in ARGV of the first	ARGV-element
that is	not	an option.	(The ARGV-elements have	been permuted
so that	those that are not options now come	last.)

OPTSTRING is a string containing the legitimate	option characters.
If an option character is seen that	is not listed in OPTSTRING,
return BAD_OPTION after	printing an	error message.	If you set `opterr'	to
zero, the error	message	is suppressed but we still return BAD_OPTION.

If a char in OPTSTRING is followed by a	colon, that	means it wants an arg,
so the following text in the same ARGV-element,	or the text	of the following
ARGV-element, is returned in `optarg'.	Two	colons mean	an option that
wants an optional arg; if there	is text	in the current ARGV-element,
it is returned in `optarg',	otherwise `optarg' is set to zero.

If OPTSTRING starts	with `-' or	`+', it	requests different methods of
handling the non-option	ARGV-elements.
See	the	comments about RETURN_IN_ORDER and REQUIRE_ORDER, above.

Long-named options begin with `--' instead of `-'.
Their names	may	be abbreviated as long as the abbreviation is unique
or is an exact match for some defined option.  If they have	an
argument, it follows the option	name in	the	same ARGV-element, separated
from the option	name by	a `=', or else the in next ARGV-element.
When `getopt' finds	a long-named option, it	returns	0 if that option's
`flag' field is	nonzero, the value of the option's `val' field
if the `flag' field	is zero.

The	elements of	ARGV aren't	really const, because we permute them.
But	we pretend they're const in	the	prototype to be	compatible
with other systems.

LONGOPTS is	a vector of	`struct	option'	terminated by an
element	containing a name which	is zero.

LONGIND	returns	the	index in LONGOPT of	the	long-named option found.
It is only valid when a	long-named option has been found by	the	most
recent call.

If LONG_ONLY is	nonzero, '-' as	well as	'--' can introduce
long-named options.	 */

int
_getopt_internal (int argc,	char *const	*argv, const char *optstring, const	struct option *longopts, int *longind, int long_only)
{
	int	option_index;

	optarg = 0;

	/* Initialize the internal data	when the first call	is made.
	Start processing options with ARGV-element 1 (since	ARGV-element 0
	is the program name); the sequence of previously skipped
	non-option ARGV-elements is	empty.	*/

	if (optind == 0)
	{
		first_nonopt = last_nonopt = optind	= 1;

		nextchar = NULL;

		/* Determine how to	handle the ordering	of options and nonoptions.	*/

		if (optstring[0] ==	'-')
		{
			ordering = RETURN_IN_ORDER;
			++optstring;
		}
		else if	(optstring[0] == '+')
		{
			ordering = REQUIRE_ORDER;
			++optstring;
		}
		else if	(getenv	("POSIXLY_CORRECT")	!= NULL)
			ordering = REQUIRE_ORDER;
		else
			ordering = PERMUTE;
	}

	if (nextchar ==	NULL ||	*nextchar == '\0')
	{
		if (ordering ==	PERMUTE)
		{
			/* If we have just processed some options following	some non-options,
			exchange them so that the options come first.  */

			if (first_nonopt !=	last_nonopt	&& last_nonopt != optind)
				exchange ((char	**)	argv);
			else if	(last_nonopt !=	optind)
				first_nonopt = optind;

			/* Now skip	any	additional non-options
			and	extend the range of	non-options	previously skipped.	 */

			while (optind <	argc
				&& (argv[optind][0]	!= '-' || argv[optind][1] == '\0')
#ifdef GETOPT_COMPAT
				&& (longopts ==	NULL
				|| argv[optind][0] != '+' || argv[optind][1] ==	'\0')
#endif				/* GETOPT_COMPAT */
				)
				optind++;
			last_nonopt	= optind;
		}

		/* Special ARGV-element	`--' means premature end of	options.
		Skip it	like a null	option,
		then exchange with previous	non-options	as if it were an option,
		then skip everything else like a non-option.  */

		if (optind != argc && !strcmp (argv[optind], "--"))
		{
			optind++;

			if (first_nonopt !=	last_nonopt	&& last_nonopt != optind)
				exchange ((char	**)	argv);
			else if	(first_nonopt == last_nonopt)
				first_nonopt = optind;
			last_nonopt	= argc;

			optind = argc;
		}

		/* If we have done all the ARGV-elements, stop the scan
		and	back over any non-options that we skipped and permuted.	 */

		if (optind == argc)
		{
			/* Set the next-arg-index to point at the non-options
			that we	previously skipped,	so the caller will digest them.	 */
			if (first_nonopt !=	last_nonopt)
				optind = first_nonopt;
			return EOF;
		}

		/* If we have come to a	non-option and did not permute it,
		either stop	the	scan or	describe it	to the caller and pass it by.  */

		if ((argv[optind][0] !=	'-'	|| argv[optind][1] == '\0')
#ifdef GETOPT_COMPAT
			&& (longopts ==	NULL
			|| argv[optind][0] != '+' || argv[optind][1] ==	'\0')
#endif				/* GETOPT_COMPAT */
			)
		{
			if (ordering ==	REQUIRE_ORDER)
				return EOF;
			optarg = argv[optind++];
			return 1;
		}

		/* We have found another option-ARGV-element.
		Start decoding its characters.	*/

		nextchar = (argv[optind] + 1
			+ (longopts	!= NULL	&& argv[optind][1] == '-'));
	}

	if (longopts !=	NULL
		&& ((argv[optind][0] ==	'-'
		&& (argv[optind][1]	== '-' || long_only))
#ifdef GETOPT_COMPAT
		|| argv[optind][0] == '+'
#endif				/* GETOPT_COMPAT */
		))
	{
		const struct option	*p;
		char *s	= nextchar;
		int	exact =	0;
		int	ambig =	0;
		const struct option	*pfound	= NULL;
		int	indfound = 0;

		while (*s && *s	!= '=')
			s++;

		/* Test	all	options	for	either exact match or abbreviated matches.	*/
		for	(p = longopts, option_index	= 0; p->name;
			p++, option_index++)
			if (!strncmp (p->name, nextchar, s - nextchar))
			{
				if (s -	nextchar ==	my_strlen (p->name))
				{
					/* Exact match found.  */
					pfound = p;
					indfound = option_index;
					exact =	1;
					break;
				}
				else if	(pfound	== NULL)
				{
					/* First nonexact match	found.	*/
					pfound = p;
					indfound = option_index;
				}
				else
					/* Second nonexact match found.	 */
					ambig =	1;
			}

			if (ambig && !exact)
			{
				if (opterr)
					fprintf	(stderr, "%s: option `%s' is ambiguous\n",
					argv[0], argv[optind]);
				nextchar +=	my_strlen (nextchar);
				optind++;
				return BAD_OPTION;
			}

			if (pfound != NULL)
			{
				option_index = indfound;
				optind++;
				if (*s)
				{
					/* Don't test has_arg with >, because some C compilers don't
					allow it to	be used	on enums.  */
					if (pfound->has_arg)
						optarg = s + 1;
					else
					{
						if (opterr)
						{
							if (argv[optind	- 1][1]	== '-')
								/* --option	*/
								fprintf	(stderr,
								"%s: option	`--%s' doesn't allow an	argument\n",
								argv[0], pfound->name);
							else
								/* +option or -option */
								fprintf	(stderr,
								"%s: option	`%c%s' doesn't allow an	argument\n",
								argv[0], argv[optind - 1][0], pfound->name);
						}
						nextchar +=	my_strlen (nextchar);
						return BAD_OPTION;
					}
				}
				else if	(pfound->has_arg ==	1)
				{
					if (optind < argc)
						optarg = argv[optind++];
					else
					{
						if (opterr)
							fprintf	(stderr, "%s: option `%s' requires an argument\n",
							argv[0], argv[optind - 1]);
						nextchar +=	my_strlen (nextchar);
						return optstring[0]	== ':' ? ':' : BAD_OPTION;
					}
				}
				nextchar +=	my_strlen (nextchar);
				if (longind	!= NULL)
					*longind = option_index;
				if (pfound->flag)
				{
					*(pfound->flag)	= pfound->val;
					return 0;
				}
				return pfound->val;
			}
			/* Can't find it as	a long option.	If this	is not getopt_long_only,
			or the option starts with '--' or is not a valid short
			option,	then it's an error.
			Otherwise interpret	it as a	short option.  */
			if (!long_only || argv[optind][1] == '-'
#ifdef GETOPT_COMPAT
				|| argv[optind][0] == '+'
#endif				/* GETOPT_COMPAT */
				|| my_index	(optstring,	*nextchar) == NULL)
			{
				if (opterr)
				{
					if (argv[optind][1]	== '-')
						/* --option	*/
						fprintf	(stderr, "%s: unrecognized option `--%s'\n",
						argv[0], nextchar);
					else
						/* +option or -option */
						fprintf	(stderr, "%s: unrecognized option `%c%s'\n",
						argv[0], argv[optind][0], nextchar);
				}
				nextchar = (char *)	"";
				optind++;
				return BAD_OPTION;
			}
	}

	/* Look	at and handle the next option-character.  */

	{
		char c = *nextchar++;
		char *temp = my_index (optstring, c);

		/* Increment `optind' when we start	to process its last	character.	*/
		if (*nextchar == '\0')
			++optind;

		if (temp ==	NULL ||	c == ':')
		{
			if (opterr)
			{
#if	0
				if (c <	040	|| c >=	0177)
					fprintf	(stderr, "%s: unrecognized option, character code 0%o\n",
					argv[0], c);
				else
					fprintf	(stderr, "%s: unrecognized option `-%c'\n",	argv[0], c);
#else
				/* 1003.2 specifies	the	format of this message.	 */
				fprintf	(stderr, "%s: illegal option --	%c\n", argv[0],	c);
#endif
			}
			optopt = c;
			return BAD_OPTION;
		}
		if (temp[1]	== ':')
		{
			if (temp[2]	== ':')
			{
				/* This	is an option that accepts an argument optionally.  */
				if (*nextchar != '\0')
				{
					optarg = nextchar;
					optind++;
				}
				else
					optarg = 0;
				nextchar = NULL;
			}
			else
			{
				/* This	is an option that requires an argument.	 */
				if (*nextchar != '\0')
				{
					optarg = nextchar;
					/* If we end this ARGV-element by taking the rest as an	arg,
					we must	advance	to the next	element	now.  */
					optind++;
				}
				else if	(optind	== argc)
				{
					if (opterr)
					{
#if	0
						fprintf	(stderr, "%s: option `-%c' requires	an argument\n",
							argv[0], c);
#else
						/* 1003.2 specifies	the	format of this message.	 */
						fprintf	(stderr, "%s: option requires an argument -- %c\n",
							argv[0], c);
#endif
					}
					optopt = c;
					if (optstring[0] ==	':')
						c =	':';
					else
						c =	BAD_OPTION;
				}
				else
					/* We already incremented `optind' once;
					increment it again when	taking next	ARGV-elt as	argument.  */
					optarg = argv[optind++];
				nextchar = NULL;
			}
		}
		return c;
	}
}

int
getopt (int	argc, char *const *argv, const char	*optstring)
{
	return _getopt_internal	(argc, argv, optstring,
		(const struct option *)	0,
		(int *)	0,
		0);
}

int
getopt_long	(int argc, char	*const *argv, const	char *options, const struct	option *long_options, int *opt_index)
{
	return _getopt_internal	(argc, argv, options, long_options,	opt_index, 0);
}