/* vi: set sw=4 ts=4: */
/*
 * universal getopt_ulflags implementation for busybox
 *
 * Copyright (C) 2003-2005  Vladimir Oleynik  <dzo@simtreas.ru>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"
#include <getopt.h>

/*      Documentation

unsigned long
bb_getopt_ulflags(int argc, char **argv, const char *applet_opts, ...)

        The command line options must be declared in const char
        *applet_opts as a string of chars, for example:

        flags = bb_getopt_ulflags(argc, argv, "rnug");

        If one of the given options is found, a flag value is added to
        the return value (an unsigned long).

        The flag value is determined by the position of the char in
        applet_opts string.  For example, in the above case:

        flags = bb_getopt_ulflags(argc, argv, "rnug");

        "r" will add 1    (bit 0)
        "n" will add 2    (bit 1)
        "u  will add 4    (bit 2)
        "g" will add 8    (bit 3)

        and so on.  You can also look at the return value as a bit
        field and each option sets one bit.

        On exit, global variable optind is set so that if you
        will do argc -= optind; argv += optind; then
        argc will be equal to number of remaining non-option
        arguments, first one would be in argv[0], next in argv[1] and so on
        (options and their parameters will be moved into argv[]
        positions prior to argv[optind]).

 ":"    If one of the options requires an argument, then add a ":"
        after the char in applet_opts and provide a pointer to store
        the argument.  For example:

        char *pointer_to_arg_for_a;
        char *pointer_to_arg_for_b;
        char *pointer_to_arg_for_c;
        char *pointer_to_arg_for_d;

        flags = bb_getopt_ulflags(argc, argv, "a:b:c:d:",
        		&pointer_to_arg_for_a, &pointer_to_arg_for_b,
        		&pointer_to_arg_for_c, &pointer_to_arg_for_d);

        The type of the pointer (char* or llist_t*) may be controlled
        by the "::" special separator that is set in the external string
        bb_opt_complementally (see below for more info).

 "::"   If option can have an *optional* argument, then add a "::"
        after its char in applet_opts and provide a pointer to store
        the argument.  Note that optional arguments _must_
        immediately follow the option: -oparam, not -o param.

 "+"    If the first character in the applet_opts string is a plus,
        then option processing will stop as soon as a non-option is
        encountered in the argv array.  Useful for applets like env
        which should not process arguments to subprograms:
        env -i ls -d /
        Here we want env to process just the '-i', not the '-d'.

const struct option *bb_applet_long_options

        This struct allows you to define long options.  The syntax for
        declaring the array is just like that of getopt's longopts.
        (see getopt(3))

        static const struct option applet_long_options[] = {
        	//name,has_arg,flag,val 
        	{ "verbose", 0, 0, 'v' },
        	{ 0, 0, 0, 0 }
        };
        bb_applet_long_options = applet_long_options;

        The last member of struct option (val) typically is set to
        matching short option from applet_opts. If there is no matching
        char in applet_opts, then:
        - return bit have next position after short options
        - if has_arg is not "no_argument", use ptr for arg also
        - bb_opt_complementally affects it too

        Note: a good applet will make long options configurable via the
        config process and not a required feature.  The current standard
        is to name the config option CONFIG_FEATURE_<applet>_LONG_OPTIONS.

const char *bb_opt_complementally

        this should be bb_opt_complementary, but we'll just keep it as
        bb_opt_complementally due to the Russian origins

 ":"    The colon (":") is used to separate groups of two or more chars
        and/or groups of chars and special characters (stating some
        conditions to be checked).

 "abc"  If groups of two or more chars are specified, the first char
        is the main option and the other chars are secondary options.
        Their flags will be turned on if the main option is found even
        if they are not specifed on the command line.  For example:

        bb_opt_complementally = "abc";
        flags = bb_getopt_ulflags(argc, argv, "abcd")

        If getopt() finds "-a" on the command line, then
        bb_getopt_ulflags's return value will be as if "-a -b -c" were
        found.

 "ww"   Adjacent double options have a counter associated which indicates
        the number of occurences of the option.
        For example the ps applet needs:
        if w is given once, GNU ps sets the width to 132,
        if w is given more than once, it is "unlimited"

        int w_counter = 0;
        bb_opt_complementally = "ww";
        bb_getopt_ulflags(argc, argv, "w", &w_counter);
        if (w_counter)
        	width = (w_counter == 1) ? 132 : INT_MAX;
        else
        	get_terminal_width(...&width...);

        w_counter is a pointer to an integer. It has to be passed to
        bb_getopt_ulflags() after all other option argument sinks.

        For example: accept multiple -v to indicate the level of verbosity
        and for each -b optarg, add optarg to my_b. Finally, if b is given,
        turn off c and vice versa:

        llist_t *my_b = NULL;
        int verbose_level = 0;
        bb_opt_complementally = "vv:b::b-c:c-b";
        f = bb_getopt_ulflags(argc, argv, "vb:c", &my_b, &verbose_level);
        if (f & 2)       // -c after -b unsets -b flag
        	while (my_b) { dosomething_with(my_b->data); my_b = my_b->link; }
        if (my_b)        // but llist is stored if -b is specified
        	free_llist(my_b);
        if (verbose_level) bb_printf("verbose level is %d\n", verbose_level);

Special characters:

 "-"    A dash between two options causes the second of the two
        to be unset (and ignored) if it is given on the command line.

        [FIXME: what if they are the same? like "x-x"? Is it ever useful?]

        For example:
        The du applet has the options "-s" and "-d depth".  If
        bb_getopt_ulflags finds -s, then -d is unset or if it finds -d
        then -s is unset.  (Note:  busybox implements the GNU
        "--max-depth" option as "-d".)  To obtain this behavior, you
        set bb_opt_complementally = "s-d:d-s".  Only one flag value is
        added to bb_getopt_ulflags's return value depending on the
        position of the options on the command line.  If one of the
        two options requires an argument pointer (":" in applet_opts
        as in "d:") optarg is set accordingly.

        char *smax_print_depth;

        bb_opt_complementally = "s-d:d-s:x-x";
        opt = bb_getopt_ulflags(argc, argv, "sd:x", &smax_print_depth);

        if (opt & 2)
        	max_print_depth = atoi(smax_print_depth);
        if (opt & 4)
        	printf("Detected odd -x usage\n");

 "-"    A dash as the first char in a bb_opt_complementally group forces
        all arguments to be treated as options, even if they have
        no leading dashes. Next char in this case can't be a digit (0-9),
        use ':' or end of line. For example:

        bb_opt_complementally = "-:w-x:x-w";
        bb_getopt_ulflags(argc, argv, "wx");

        Allows any arguments to be given without a dash (./program w x)
        as well as with a dash (./program -x).

 "-N"   A dash as the first char in a bb_opt_complementally group followed
        by a single digit (0-9) means that at least N non-option
        arguments must be present on the command line

 "V-"   An option with dash before colon or end-of-line results in
        bb_show_usage being called if this option is encountered.
        This is typically used to implement "print verbose usage message
        and exit" option.

 "--"   A double dash between two options, or between an option and a group
        of options, means that they are mutually exclusive.  Unlike
        the "-" case above, an error will be forced if the options
        are used together.

        For example:
        The cut applet must have only one type of list specified, so
        -b, -c and -f are mutally exclusive and should raise an error
        if specified together.  In this case you must set
        bb_opt_complementally = "b--cf:c--bf:f--bc".  If two of the
        mutually exclusive options are found, bb_getopt_ulflags's
        return value will have the error flag set (BB_GETOPT_ERROR) so
        that we can check for it:

        if (flags & BB_GETOPT_ERROR)
        	bb_show_usage();

 "x--x" Variation of the above, it means that -x option should occur
        at most once.

 "?"    A "?" as the first char in a bb_opt_complementally group means:
        if BB_GETOPT_ERROR is detected, don't return, call bb_show_usage
        and exit instead. Next char after '?' can't be a digit.

 "?N"   A "?" as the first char in a bb_opt_complementally group followed
        by a single digit (0-9) means that at most N arguments must be present
        on the command line.

 "::"   A double colon after a char in bb_opt_complementally means that the
        option can occur multiple times. Each occurrence will be saved as
        a llist_t element instead of char*.

        For example:
        The grep applet can have one or more "-e pattern" arguments.
        In this case you should use bb_getopt_ulflags() as follows:

        llist_t *patterns = NULL;

        (this pointer must be initializated to NULL if the list is empty
        as required by *llist_add_to(llist_t *old_head, char *new_item).)

        bb_opt_complementally = "e::";

        bb_getopt_ulflags(argc, argv, "e:", &patterns);
        $ grep -e user -e root /etc/passwd
        root:x:0:0:root:/root:/bin/bash
        user:x:500:500::/home/user:/bin/bash

 "--"   A double dash at the beginning of bb_opt_complementally means the
        argv[1] string should always be treated as options, even if it isn't
        prefixed with a "-".  This is useful for special syntax in applets
        such as "ar" and "tar":
        tar xvf foo.tar

 "?"    An "?" between an option and a group of options means that
        at least one of them is required to occur if the first option
        occurs in preceding command line arguments.

        For example from "id" applet:

        // Don't allow -n -r -rn -ug -rug -nug -rnug
        bb_opt_complementally = "r?ug:n?ug:?u--g:g--u";
        flags = bb_getopt_ulflags(argc, argv, "rnug");

        This example allowed only:
        $ id; id -u; id -g; id -ru; id -nu; id -rg; id -ng; id -rnu; id -rng

 "X"    A bb_opt_complementally group with just a single letter means
        that this option is required. If more than one such group exists,
        at least one option is required to occur (not all of them).
        For example from "start-stop-daemon" applet:

        // Don't allow -KS -SK, but -S or -K is required
        bb_opt_complementally = "K:S:?K--S:S--K";
        flags = bb_getopt_ulflags(argc, argv, "KS...);


        Don't forget to use ':'. For example, "?322-22-23X-x-a"
        is interpreted as "?3:22:-2:2-2:2-3Xa:2--x" -
        max 3 args; count uses of '-2'; min 2 args; if there is
        a '-2' option then unset '-3', '-X' and '-a'; if there is
        a '-2' and after it a '-x' then error out.
*/

/* this should be bb_opt_complementary, but we'll just keep it as
   bb_opt_complementally due to the Russian origins */
const char *bb_opt_complementally;

typedef struct {
	int opt;
	int list_flg;
	unsigned long switch_on;
	unsigned long switch_off;
	unsigned long incongruously;
	unsigned long requires;
	void **optarg;               /* char **optarg or llist_t **optarg */
	int *counter;
} t_complementally;

/* You can set bb_applet_long_options for parse called long options */
#if ENABLE_GETOPT_LONG
static const struct option bb_default_long_options[] = {
/*      { "help", 0, NULL, '?' }, */
	{ 0, 0, 0, 0 }
};

const struct option *bb_applet_long_options = bb_default_long_options;
#endif

unsigned long
bb_getopt_ulflags(int argc, char **argv, const char *applet_opts, ...)
{
	unsigned long flags = 0;
	unsigned long requires = 0;
	t_complementally complementally[sizeof(flags) * 8 + 1];
	int c;
	const unsigned char *s;
	t_complementally *on_off;
	va_list p;
#if ENABLE_GETOPT_LONG
	const struct option *l_o;
#endif
	unsigned long trigger;
	char **pargv = NULL;
	int min_arg = 0;
	int max_arg = -1;

#define SHOW_USAGE_IF_ERROR     1
#define ALL_ARGV_IS_OPTS        2
#define FIRST_ARGV_IS_OPT       4
#define FREE_FIRST_ARGV_IS_OPT  8
	int spec_flgs = 0;

	va_start(p, applet_opts);

	c = 0;
	on_off = complementally;
	memset(on_off, 0, sizeof(complementally));

	/* skip GNU extension */
	s = (const unsigned char *)applet_opts;
	if (*s == '+' || *s == '-')
		s++;
	for (; *s; s++) {
		if (c >= (int)(sizeof(flags)*8))
			break;
		on_off->opt = *s;
		on_off->switch_on = (1 << c);
		if (s[1] == ':') {
			on_off->optarg = va_arg(p, void **);
			do
				s++;
			while (s[1] == ':');
		}
		on_off++;
		c++;
	}

#if ENABLE_GETOPT_LONG
	for (l_o = bb_applet_long_options; l_o->name; l_o++) {
		if (l_o->flag)
			continue;
		for (on_off = complementally; on_off->opt != 0; on_off++)
			if (on_off->opt == l_o->val)
				break;
		if (on_off->opt == 0) {
			if (c >= (int)(sizeof(flags)*8))
				break;
			on_off->opt = l_o->val;
			on_off->switch_on = (1 << c);
			if (l_o->has_arg != no_argument)
				on_off->optarg = va_arg(p, void **);
			c++;
		}
	}
#endif /* ENABLE_GETOPT_LONG */
	for (s = (const unsigned char *)bb_opt_complementally; s && *s; s++) {
		t_complementally *pair;
		unsigned long *pair_switch;

		if (*s == ':')
			continue;
		c = s[1];
		if (*s == '?') {
			if (c < '0' || c > '9') {
				spec_flgs |= SHOW_USAGE_IF_ERROR;
			} else {
				max_arg = c - '0';
				s++;
			}
			continue;
		}
		if (*s == '-') {
			if (c < '0' || c > '9') {
				if (c == '-') {
					spec_flgs |= FIRST_ARGV_IS_OPT;
					s++;
				} else
					spec_flgs |= ALL_ARGV_IS_OPTS;
			} else {
				min_arg = c - '0';
				s++;
			}
			continue;
		}
		for (on_off = complementally; on_off->opt; on_off++)
			if (on_off->opt == *s)
				break;
		if (c == ':' && s[2] == ':') {
			on_off->list_flg++;
			continue;
		}
		if (c == ':' || c == '\0') {
			requires |= on_off->switch_on;
			continue;
		}
		if (c == '-' && (s[2] == ':' || s[2] == '\0')) {
			flags |= on_off->switch_on;
			on_off->incongruously |= on_off->switch_on;
			s++;
			continue;
		}
		if (c == *s) {
			on_off->counter = va_arg(p, int *);
			s++;
		}
		pair = on_off;
		pair_switch = &(pair->switch_on);
		for (s++; *s && *s != ':'; s++) {
			if (*s == '?') {
				pair_switch = &(pair->requires);
			} else if (*s == '-') {
				if (pair_switch == &(pair->switch_off))
					pair_switch = &(pair->incongruously);
				else
					pair_switch = &(pair->switch_off);
			} else {
				for (on_off = complementally; on_off->opt; on_off++)
					if (on_off->opt == *s) {
						*pair_switch |= on_off->switch_on;
						break;
					}
			}
		}
		s--;
	}
	va_end (p);

#if ENABLE_AR || ENABLE_TAR
	if (spec_flgs & FIRST_ARGV_IS_OPT) {
		if (argv[1] && argv[1][0] != '-' && argv[1][0] != '\0') {
			argv[1] = xasprintf("-%s", argv[1]);
			if (ENABLE_FEATURE_CLEAN_UP)
				spec_flgs |= FREE_FIRST_ARGV_IS_OPT;
		}
	}
#endif
#if ENABLE_GETOPT_LONG
	while ((c = getopt_long(argc, argv, applet_opts,
				 bb_applet_long_options, NULL)) >= 0) {
#else
	while ((c = getopt(argc, argv, applet_opts)) >= 0) {
#endif /* ENABLE_GETOPT_LONG */
loop_arg_is_opt:
		for (on_off = complementally; on_off->opt != c; on_off++) {
			/* c==0 if long opt have non NULL flag */
			if (on_off->opt == 0 && c != 0)
				bb_show_usage();
		}
		if (flags & on_off->incongruously) {
			if ((spec_flgs & SHOW_USAGE_IF_ERROR))
				bb_show_usage();
			flags |= BB_GETOPT_ERROR;
		}
		trigger = on_off->switch_on & on_off->switch_off;
		flags &= ~(on_off->switch_off ^ trigger);
		flags |= on_off->switch_on ^ trigger;
		flags ^= trigger;
		if (on_off->counter)
			(*(on_off->counter))++;
		if (on_off->list_flg) {
			llist_add_to((llist_t **)(on_off->optarg), optarg);
		} else if (on_off->optarg) {
			*(char **)(on_off->optarg) = optarg;
		}
		if (pargv != NULL)
			break;
	}

	if (spec_flgs & ALL_ARGV_IS_OPTS) {
		/* process argv is option, for example "ps" applet */
		if (pargv == NULL)
			pargv = argv + optind;
		while (*pargv) {
			c = **pargv;
			if (c == '\0') {
				pargv++;
			} else {
				(*pargv)++;
				goto loop_arg_is_opt;
			}
		}
	}

#if (ENABLE_AR || ENABLE_TAR) && ENABLE_FEATURE_CLEAN_UP
	if (spec_flgs & FREE_FIRST_ARGV_IS_OPT)
		free(argv[1]);
#endif
	/* check depending requires for given options */
	for (on_off = complementally; on_off->opt; on_off++) {
		if (on_off->requires && (flags & on_off->switch_on) &&
					(flags & on_off->requires) == 0)
			bb_show_usage();
	}
	if (requires && (flags & requires) == 0)
		bb_show_usage();
	argc -= optind;
	if (argc < min_arg || (max_arg >= 0 && argc > max_arg))
		bb_show_usage();
	return flags;
}