/*
 * Copyright (c) 2002 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */
/*-
 * 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.
 */
/** @file
    @brief Implementations of getopt() and getopt_long() work-alike functions.

    This code was taken from FreeBSD and slightly modified, mostly to rename
    symbols with external linkage to avoid naming conflicts in systems where
    there are real getopt()/getopt_long() implementations, and for portability.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <redfs.h>
#include <redgetopt.h>
#include <redtestutils.h>
#include <rederrno.h>


int32_t red_opterr = 1;     /* if error message should be printed */
int32_t red_optind = 1;     /* index into parent argv vector */
int32_t red_optopt = '?';   /* character checked for validity */
int32_t red_optreset;       /* reset RedGetopt */
const char *red_optarg;     /* argument associated with option */

#define PRINT_ERROR ((red_opterr) && (*options != ':'))

#define FLAG_PERMUTE    0x01    /* permute non-options to the end of argv */
#define FLAG_ALLARGS    0x02    /* treat non-options as args to option "-1" */
#define FLAG_LONGONLY   0x04    /* operate as RedGetoptLongOnly */

/* return values */
#define BADCH       (int)'?'
#define BADARG      ((*options == ':') ? (int)':' : (int)'?')
#define INORDER     (int)1

#define EMSG        ""

#define NO_PREFIX   (-1)
#define D_PREFIX    0
#define DD_PREFIX   1
#define W_PREFIX    2

static int gcd(int a, int b);
static void permute_args(int panonopt_start, int panonopt_end, int opt_end, char * const *nargv);
static int parse_long_options(char * const *nargv, const char *options, const REDOPTION *long_options, int32_t *idx, int short_too, int flags);
static int getopt_internal(int nargc, char * const *nargv, const char *options, const REDOPTION *long_options, int32_t *idx, int flags);

static const char *place = EMSG; /* option letter processing */

/* XXX: set red_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\n";
static const char illoptchar[] = "illegal option -- %c\n"; /* From P1003.2 */
static int dash_prefix = NO_PREFIX;
static const char gnuoptchar[] = "invalid option -- %c\n";

static const char recargstring[] = "option `%s%s' requires an argument\n";
static const char ambig[] = "option `%s%s' is ambiguous\n";
static const char noarg[] = "option `%s%s' doesn't allow an argument\n";
static const char illoptstring[] = "unrecognized option `%s%s'\n";

/*
 * 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 * const *nargv)
{
    int cstart, cyclelen, i, j, ncycle, nnonopts, nopts, pos;
    char *swap;

    /*
     * 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];
            ((char **) nargv)[pos] = nargv[cstart];
            ((char **)nargv)[cstart] = swap;
        }
    }
}

/*
 * parse_long_options --
 *  Parse long options in argc/argv argument vector.
 * Returns -1 if short_too is set and the option does not match long_options.
 */
static int
parse_long_options(char * const *nargv, const char *options,
    const REDOPTION *long_options, int32_t *idx, int short_too, int flags)
{
    const char *current_argv, *has_equal, *current_dash;
    size_t current_argv_len;
    int i, match, exact_match, second_partial_match;

    current_argv = place;
    switch (dash_prefix) {
        case D_PREFIX:
            current_dash = "-";
            break;
        case DD_PREFIX:
            current_dash = "--";
            break;
        case W_PREFIX:
            current_dash = "-W ";
            break;
        default:
            current_dash = "";
            break;
    }
    match = -1;
    exact_match = 0;
    second_partial_match = 0;

    red_optind++;

    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) == current_argv_len) {
            /* exact match */
            match = i;
            exact_match = 1;
            break;
        }
        /*
         * If this is a known short option, don't allow
         * a partial match of a single character.
         */
        if (short_too && current_argv_len == 1)
            continue;

        if (match == -1)    /* first partial match */
            match = i;
        else if ((flags & FLAG_LONGONLY) ||
             long_options[i].has_arg !=
                 long_options[match].has_arg ||
             long_options[i].flag != long_options[match].flag ||
             long_options[i].val != long_options[match].val)
            second_partial_match = 1;
    }
    if (!exact_match && second_partial_match) {
        /* ambiguous abbreviation */
        if (PRINT_ERROR)
            fprintf(stderr,
                 ambig,
                 current_dash,
                 current_argv);
        red_optopt = 0;
        return (BADCH);
    }
    if (match != -1) {      /* option found */
        if (long_options[match].has_arg == red_no_argument
            && has_equal) {
            if (PRINT_ERROR)
                fprintf(stderr,
                     noarg,
                     current_dash,
                     current_argv);
            /*
             * XXX: GNU sets red_optopt to val regardless of flag
             */
            if (long_options[match].flag == NULL)
                red_optopt = long_options[match].val;
            else
                red_optopt = 0;
            return (BADCH);
        }
        if (long_options[match].has_arg == red_required_argument ||
            long_options[match].has_arg == red_optional_argument) {
            if (has_equal)
                red_optarg = has_equal;
            else if (long_options[match].has_arg ==
                red_required_argument) {
                /*
                 * optional argument doesn't use next nargv
                 */
                red_optarg = nargv[red_optind++];
            }
        }
        if ((long_options[match].has_arg == red_required_argument)
            && (red_optarg == NULL)) {
            /*
             * Missing argument; leading ':' indicates no error
             * should be generated.
             */
            if (PRINT_ERROR)
                fprintf(stderr,
                    recargstring,
                    current_dash,
                    current_argv);
            /*
             * XXX: GNU sets red_optopt to val regardless of flag
             */
            if (long_options[match].flag == NULL)
                red_optopt = long_options[match].val;
            else
                red_optopt = 0;
            --red_optind;
            return (BADARG);
        }
    } else {            /* unknown option */
        if (short_too) {
            --red_optind;
            return (-1);
        }
        if (PRINT_ERROR)
            fprintf(stderr,
                  illoptstring,
                  current_dash,
                  current_argv);
        red_optopt = 0;
        return (BADCH);
    }
    if (idx)
        *idx = match;
    if (long_options[match].flag) {
        *long_options[match].flag = long_options[match].val;
        return (0);
    } else
        return (long_options[match].val);
}

/*
 * getopt_internal --
 *  Parse argc/argv argument vector.  Called by user level routines.
 */
static int
getopt_internal(int nargc, char * const *nargv, const char *options,
    const REDOPTION *long_options, int32_t *idx, int flags)
{
    char *oli;              /* option letter list index */
    int optchar, short_too;

    if (options == NULL)
        return (-1);

    /*
     * XXX Some GNU programs (like cvs) set red_optind to 0 instead of
     * XXX using red_optreset.  Work around this braindamage.
     */
    if (red_optind == 0)
        red_optind = red_optreset = 1;

    /*
     * Disable GNU extensions if options string begins with a '+'.
     */
    if (*options == '-')
        flags |= FLAG_ALLARGS;
    else if (*options == '+')
        flags &= ~FLAG_PERMUTE;
    if (*options == '+' || *options == '-')
        options++;

    red_optarg = NULL;
    if (red_optreset)
        nonopt_start = nonopt_end = -1;
start:
    if (red_optreset || !*place) {      /* update scanning pointer */
        red_optreset = 0;
        if (red_optind >= nargc) {          /* end of argument vector */
            place = EMSG;
            if (nonopt_end != -1) {
                /* do permutation, if we have to */
                permute_args(nonopt_start, nonopt_end,
                    red_optind, nargv);
                red_optind -= nonopt_end - nonopt_start;
            }
            else if (nonopt_start != -1) {
                /*
                 * If we skipped non-options, set red_optind
                 * to the first of them.
                 */
                red_optind = nonopt_start;
            }
            nonopt_start = nonopt_end = -1;
            return (-1);
        }
        if (*(place = nargv[red_optind]) != '-' || place[1] == '\0') {
            place = EMSG;       /* found non-option */
            if (flags & FLAG_ALLARGS) {
                /*
                 * GNU extension:
                 * return non-option as argument to option 1
                 */
                red_optarg = nargv[red_optind++];
                return (INORDER);
            }
            if (!(flags & FLAG_PERMUTE)) {
                /*
                 * If no permutation wanted, stop parsing
                 * at first non-option.
                 */
                return (-1);
            }
            /* do permutation */
            if (nonopt_start == -1)
                nonopt_start = red_optind;
            else if (nonopt_end != -1) {
                permute_args(nonopt_start, nonopt_end,
                    red_optind, nargv);
                nonopt_start = red_optind -
                    (nonopt_end - nonopt_start);
                nonopt_end = -1;
            }
            red_optind++;
            /* process next argument */
            goto start;
        }
        if (nonopt_start != -1 && nonopt_end == -1)
            nonopt_end = red_optind;

        /*
         * If we have "-" do nothing, if "--" we are done.
         */
        if (place[1] != '\0' && *++place == '-' && place[1] == '\0') {
            red_optind++;
            place = EMSG;
            /*
             * We found an option (--), so if we skipped
             * non-options, we have to permute.
             */
            if (nonopt_end != -1) {
                permute_args(nonopt_start, nonopt_end,
                    red_optind, nargv);
                red_optind -= nonopt_end - nonopt_start;
            }
            nonopt_start = nonopt_end = -1;
            return (-1);
        }
    }

    /*
     * Check long options if:
     *  1) we were passed some
     *  2) the arg is not just "-"
     *  3) either the arg starts with -- we are RedGetoptLongOnly()
     */
    if (long_options != NULL && place != nargv[red_optind] &&
        (*place == '-' || (flags & FLAG_LONGONLY))) {
        short_too = 0;
        dash_prefix = D_PREFIX;
        if (*place == '-') {
            place++;        /* --foo long option */
            dash_prefix = DD_PREFIX;
        } else if (*place != ':' && strchr(options, *place) != NULL)
            short_too = 1;      /* could be short option too */

        optchar = parse_long_options(nargv, options, long_options,
            idx, short_too, flags);
        if (optchar != -1) {
            place = EMSG;
            return (optchar);
        }
    }

    if ((optchar = (int)*place++) == (int)':' ||
        (optchar == (int)'-' && *place != '\0') ||
        (oli = strchr(options, optchar)) == NULL) {
        /*
         * If the user specified "-" and  '-' isn't listed in
         * options, return -1 (non-option) as per POSIX.
         * Otherwise, it is an unknown option character (or ':').
         */
        if (optchar == (int)'-' && *place == '\0')
            return (-1);
        if (!*place)
            ++red_optind;
        if (PRINT_ERROR)
            fprintf(stderr, gnuoptchar, optchar);
        red_optopt = optchar;
        return (BADCH);
    }
    if (long_options != NULL && optchar == 'W' && oli[1] == ';') {
        /* -W long-option */
        if (*place)         /* no space */
            /* NOTHING */;
        else if (++red_optind >= nargc) {   /* no arg */
            place = EMSG;
            if (PRINT_ERROR)
                fprintf(stderr, recargchar, optchar);
            red_optopt = optchar;
            return (BADARG);
        } else              /* white space */
            place = nargv[red_optind];
        dash_prefix = W_PREFIX;
        optchar = parse_long_options(nargv, options, long_options,
            idx, 0, flags);
        place = EMSG;
        return (optchar);
    }
    if (*++oli != ':') {            /* doesn't take argument */
        if (!*place)
            ++red_optind;
    } else {                /* takes (optional) argument */
        red_optarg = NULL;
        if (*place)         /* no white space */
            red_optarg = place;
        else if (oli[1] != ':') {   /* arg not optional */
            if (++red_optind >= nargc) {    /* no arg */
                place = EMSG;
                if (PRINT_ERROR)
                    fprintf(stderr, recargchar, optchar);
                red_optopt = optchar;
                return (BADARG);
            } else
                red_optarg = nargv[red_optind];
        }
        place = EMSG;
        ++red_optind;
    }
    /* dump back option letter */
    return (optchar);
}


/** @brief Get option character from command line argument list.

    For more details, consult the getopt() man pages, since this function is
    generally similar.

    @param nargc    Number of arguments (argc passed into main()).
    @param nargv    Argument vector (argv passed into main()).
    @param options  String of option characters.

    @return The next known option character in @p options.  If a character not
            found in @p options is found or if an option is missing an argument,
            it returns '?'.  Returns -1 when the argument list is exhausted.
*/
int32_t RedGetopt(
    int32_t         nargc,
    char * const   *nargv,
    const char     *options)
{
    return getopt_internal(nargc, nargv, options, NULL, NULL, FLAG_PERMUTE);
}


/** @brief Get long options from command line argument list.

    For more details, consult the getopt_long() man pages, since this function
    is generally similar.

    @param nargc        Number of arguments (argc passed into main()).
    @param nargv        Argument vector (argv passed into main()).
    @param options      String of option characters.
    @param long_options The long options; the last element of this array must be
                        filled with zeroes.
    @param idx          If non-NULL, then populated with the index of the long
                        option relative to @p long_options.

    @return If the flag field in REDOPTION is NULL, returns the value specified
            in the val field, which is usually just the corresponding short
            option.  If flag is non-NULL, returns zero and stores val in the
            location pointed to by flag.  Returns ':' if an option was missing
            its argument, '?' for an unknown option, and -1 when the argument
            list is exhausted.
*/
int32_t RedGetoptLong(
    int32_t             nargc,
    char * const       *nargv,
    const char         *options,
    const REDOPTION    *long_options,
    int32_t            *idx)
{
    return getopt_internal(nargc, nargv, options, long_options, idx, FLAG_PERMUTE);
}