/*	$NetBSD: getopt_long.c,v 1.25 2009/03/20 14:05:54 joerg Exp $	*/

/*-
 * Copyright (c) 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Dieter Baron and Thomas Klausner.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "mowgli.h"

int mowgli_opterr = 1;	/* if error message should be printed */
int mowgli_optind = 1;	/* index into parent argv vector */
int mowgli_optopt = '?';/* character checked for validity */
int mowgli_optreset = 0;/* reset getopt */
char *mowgli_optarg = NULL;	/* argument associated with option */

/* XXX: suppress const warnings */
#define PTR_UNCONSTIFY(a) ((void *)((uintptr_t)((const void *)(a))))

#define IGNORE_FIRST (*options == '-' || *options == '+')
#define PRINT_ERROR ((mowgli_opterr) && ((*options != ':') \
					 || (IGNORE_FIRST && options[1] != ':')))
#define IS_POSIXLY_CORRECT (getenv("POSIXLY_CORRECT") != NULL)
#define PERMUTE (!IS_POSIXLY_CORRECT && !IGNORE_FIRST)

/* XXX: GNU ignores PC if *options == '-' */
#define IN_ORDER (!IS_POSIXLY_CORRECT && *options == '-')

/* return values */
#define BADCH (int) '?'
#define BADARG ((IGNORE_FIRST && options[1] == ':') \
		|| (*options == ':') ? (int) ':' : (int) '?')
#define INORDER (int) 1

#define EMSG ""

static inline void MOWGLI_FATTR_PRINTF(1, 2)
warnx(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	fputc('\n', stderr);
	va_end(ap);
}

static int getopt_internal(int, char **, const char *);
static int gcd(int, int);
static void permute_args(int, int, int, char **);

static const char *place = EMSG;/* option letter processing */

/* XXX: set mowgli_optreset to 1 rather than these two */
static int nonopt_start = -1;	/* first non option argument (for permute) */
static int nonopt_end = -1;	/* first option after non options (for permute) */

/* Error messages */
static const char recargchar[] = "option requires an argument -- %c";
static const char recargstring[] = "option requires an argument -- %s";
static const char ambig[] = "ambiguous option -- %.*s";
static const char noarg[] = "option doesn't take an argument -- %.*s";
static const char illoptchar[] = "unknown option -- %c";
static const char illoptstring[] = "unknown option -- %s";

/*
 * Compute the greatest common divisor of a and b.
 */
static int
gcd(int a, int b)
{
	int c;

	c = a % b;

	while (c != 0)
	{
		a = b;
		b = c;
		c = a % b;
	}

	return b;
}

/*
 * Exchange the block from nonopt_start to nonopt_end with the block
 * from nonopt_end to opt_end (keeping the same order of arguments
 * in each block).
 */
static void
permute_args(int panonopt_start, int panonopt_end, int opt_end, char **nargv)
{
	int cstart, cyclelen, i, j, ncycle, nnonopts, nopts, pos;
	char *swap;

	return_if_fail(nargv != NULL);

	/*
	 * compute lengths of blocks and number and size of cycles
	 */
	nnonopts = panonopt_end - panonopt_start;
	nopts = opt_end - panonopt_end;
	ncycle = gcd(nnonopts, nopts);
	cyclelen = (opt_end - panonopt_start) / ncycle;

	for (i = 0; i < ncycle; i++)
	{
		cstart = panonopt_end + i;
		pos = cstart;

		for (j = 0; j < cyclelen; j++)
		{
			if (pos >= panonopt_end)
				pos -= nnonopts;
			else
				pos += nopts;

			swap = nargv[pos];
			nargv[pos] = nargv[cstart];
			nargv[cstart] = swap;
		}
	}
}

/*
 * getopt_internal --
 *	Parse argc/argv argument vector.  Called by user level routines.
 *  Returns -2 if -- is found (can be long option or end of options marker).
 */
static int
getopt_internal(int nargc, char **nargv, const char *options)
{
	char *oli;	/* option letter list index */
	int optchar;

	return_val_if_fail(nargv != NULL, -1);
	return_val_if_fail(options != NULL, -1);

	mowgli_optarg = NULL;

	/*
	 * XXX Some programs (like rsyncd) expect to be able to
	 * XXX re-initialize mowgli_optind to 0 and have getopt_long(3)
	 * XXX properly function again.  Work around this braindamage.
	 */
	if (mowgli_optind == 0)
		mowgli_optind = 1;

	if (mowgli_optreset)
		nonopt_start = nonopt_end = -1;

start:

	if (mowgli_optreset || !*place)	/* update scanning pointer */
	{
		mowgli_optreset = 0;

		if (mowgli_optind >= nargc)	/* end of argument vector */
		{
			place = EMSG;

			if (nonopt_end != -1)
			{
				/* do permutation, if we have to */
				permute_args(nonopt_start, nonopt_end,
					     mowgli_optind, nargv);
				mowgli_optind -= nonopt_end - nonopt_start;
			}
			else if (nonopt_start != -1)
			{
				/*
				 * If we skipped non-options, set mowgli_optind
				 * to the first of them.
				 */
				mowgli_optind = nonopt_start;
			}

			nonopt_start = nonopt_end = -1;
			return -1;
		}

		if ((*(place = nargv[mowgli_optind]) != '-')
		    || (place[1] == '\0'))	/* found non-option */
		{
			place = EMSG;

			if (IN_ORDER)
			{
				/*
				 * GNU extension:
				 * return non-option as argument to option 1
				 */
				mowgli_optarg = nargv[mowgli_optind++];
				return INORDER;
			}

			if (!PERMUTE)
				/*
				 * if no permutation wanted, stop parsing
				 * at first non-option
				 */
				return -1;

			/* do permutation */
			if (nonopt_start == -1)
			{
				nonopt_start = mowgli_optind;
			}
			else if (nonopt_end != -1)
			{
				permute_args(nonopt_start, nonopt_end,
					     mowgli_optind, nargv);
				nonopt_start = mowgli_optind -
					       (nonopt_end - nonopt_start);
				nonopt_end = -1;
			}

			mowgli_optind++;

			/* process next argument */
			goto start;
		}

		if ((nonopt_start != -1) && (nonopt_end == -1))
			nonopt_end = mowgli_optind;

		if (place[1] && (*++place == '-'))	/* found "--" */
		{
			place++;
			return -2;
		}
	}

	if (((optchar = (int) *place++) == (int) ':') ||
	    ((oli = strchr(options + (IGNORE_FIRST ? 1 : 0), optchar)) == NULL))
	{
		/* option letter unknown or ':' */
		if (!*place)
			++mowgli_optind;

		if (PRINT_ERROR)
			warnx(illoptchar, optchar);

		mowgli_optopt = optchar;
		return BADCH;
	}

	if ((optchar == 'W') && (oli[1] == ';'))/* -W long-option */
	{	/* XXX: what if no long options provided (called by getopt)? */
		if (*place)
			return -2;

		if (++mowgli_optind >= nargc)	/* no arg */
		{
			place = EMSG;

			if (PRINT_ERROR)
				warnx(recargchar, optchar);

			mowgli_optopt = optchar;
			return BADARG;
		}
		else				/* white space */
		{
			place = nargv[mowgli_optind];
		}

		/*
		 * Handle -W arg the same as --arg (which causes getopt to
		 * stop parsing).
		 */
		return -2;
	}

	if (*++oli != ':')	/* doesn't take argument */
	{
		if (!*place)
			++mowgli_optind;
	}
	else					/* takes (optional) argument */
	{
		mowgli_optarg = NULL;

		if (*place)	/* no white space */
		{
			mowgli_optarg = PTR_UNCONSTIFY(place);
		}

		/* XXX: disable test for :: if PC? (GNU doesn't) */
		else if (oli[1] != ':')	/* arg not optional */
		{
			if (++mowgli_optind >= nargc)	/* no arg */
			{
				place = EMSG;

				if (PRINT_ERROR)
					warnx(recargchar, optchar);

				mowgli_optopt = optchar;
				return BADARG;
			}
			else
			{
				mowgli_optarg = nargv[mowgli_optind];
			}
		}

		place = EMSG;
		++mowgli_optind;
	}

	/* dump back option letter */
	return optchar;
}

/*
 * getopt --
 *	Parse argc/argv argument vector.
 *
 * [eventually this will replace the real getopt]
 */
int mowgli_getopt(nargc, nargv, options)
int nargc;

char *const *nargv;
const char *options;
{
	int retval;

	return_val_if_fail(nargv != NULL, -1);
	return_val_if_fail(options != NULL, -1);

	retval = getopt_internal(nargc, PTR_UNCONSTIFY(nargv), options);

	if (retval == -2)
	{
		++mowgli_optind;

		/*
		 * We found an option (--), so if we skipped non-options,
		 * we have to permute.
		 */
		if (nonopt_end != -1)
		{
			permute_args(nonopt_start, nonopt_end, mowgli_optind,
				     PTR_UNCONSTIFY(nargv));
			mowgli_optind -= nonopt_end - nonopt_start;
		}

		nonopt_start = nonopt_end = -1;
		retval = -1;
	}

	return retval;
}

/*
 * getopt_long --
 *	Parse argc/argv argument vector.
 */
int
mowgli_getopt_long(int nargc, char *const *nargv, const char *options, const mowgli_getopt_option_t *long_options, int *idx)
{
	int retval;

#define IDENTICAL_INTERPRETATION(_x, _y) \
	(long_options[(_x)].has_arg == long_options[(_y)].has_arg && \
	 long_options[(_x)].flag == long_options[(_y)].flag && \
	 long_options[(_x)].val == long_options[(_y)].val)

	return_val_if_fail(nargv != NULL, -1);
	return_val_if_fail(options != NULL, -1);
	return_val_if_fail(long_options != NULL, -1);

	/* idx may be NULL */

	retval = getopt_internal(nargc, PTR_UNCONSTIFY(nargv), options);

	if (retval == -2)
	{
		char *current_argv, *has_equal;
		size_t current_argv_len;
		int i, ambiguous, match;

		current_argv = PTR_UNCONSTIFY(place);
		match = -1;
		ambiguous = 0;

		mowgli_optind++;
		place = EMSG;

		if (*current_argv == '\0')	/* found "--" */
		{	/*
			 * We found an option (--), so if we skipped
			 * non-options, we have to permute.
			 */
			if (nonopt_end != -1)
			{
				permute_args(nonopt_start, nonopt_end,
					     mowgli_optind, PTR_UNCONSTIFY(nargv));
				mowgli_optind -= nonopt_end - nonopt_start;
			}

			nonopt_start = nonopt_end = -1;
			return -1;
		}

		if ((has_equal = strchr(current_argv, '=')) != NULL)
		{
			/* argument found (--option=arg) */
			current_argv_len = has_equal - current_argv;
			has_equal++;
		}
		else
		{
			current_argv_len = strlen(current_argv);
		}

		for (i = 0; long_options[i].name; i++)
		{
			/* find matching long option */
			if (strncmp(current_argv, long_options[i].name,
				    current_argv_len))
				continue;

			if (strlen(long_options[i].name) ==
			    (unsigned) current_argv_len)
			{
				/* exact match */
				match = i;
				ambiguous = 0;
				break;
			}

			if (match == -1)/* partial match */
				match = i;
			else if (!IDENTICAL_INTERPRETATION(i, match))
				ambiguous = 1;
		}

		if (ambiguous)
		{
			/* ambiguous abbreviation */
			if (PRINT_ERROR)
				warnx(ambig, (int) current_argv_len,
				      current_argv);

			mowgli_optopt = 0;
			return BADCH;
		}

		if (match != -1)/* option found */
		{
			if ((long_options[match].has_arg == no_argument)
			    && has_equal)
			{
				if (PRINT_ERROR)
					warnx(noarg, (int) current_argv_len,
					      current_argv);

				/*
				 * XXX: GNU sets mowgli_optopt to val regardless of
				 * flag
				 */
				if (long_options[match].flag == NULL)
					mowgli_optopt = long_options[match].val;
				else
					mowgli_optopt = 0;

				return BADARG;
			}

			if ((long_options[match].has_arg == required_argument) ||
			    (long_options[match].has_arg == optional_argument))
			{
				if (has_equal)
					mowgli_optarg = has_equal;
				else if (long_options[match].has_arg ==
					 required_argument)
					/*
					 * optional argument doesn't use
					 * next nargv
					 */
					mowgli_optarg = nargv[mowgli_optind++];
			}

			if ((long_options[match].has_arg == required_argument)
			    && (mowgli_optarg == NULL))
			{
				/*
				 * Missing argument; leading ':'
				 * indicates no error should be generated
				 */
				if (PRINT_ERROR)
					warnx(recargstring, current_argv);

				/*
				 * XXX: GNU sets mowgli_optopt to val regardless
				 * of flag
				 */
				if (long_options[match].flag == NULL)
					mowgli_optopt = long_options[match].val;
				else
					mowgli_optopt = 0;

				--mowgli_optind;
				return BADARG;
			}
		}
		else				/* unknown option */
		{
			if (PRINT_ERROR)
				warnx(illoptstring, current_argv);

			mowgli_optopt = 0;
			return BADCH;
		}

		if (long_options[match].flag)
		{
			*long_options[match].flag = long_options[match].val;
			retval = 0;
		}
		else
		{
			retval = long_options[match].val;
		}

		if (idx)
			*idx = match;
	}

	return retval;
#undef IDENTICAL_INTERPRETATION
}
