/*****************************************************************************
* getopt.c - competent and free getopt library.
* $Header: /cvsroot/freegetopt/freegetopt/getopt.c,v 1.2 2003/10/26 03:10:20 vindaci Exp $
*
* Copyright (c)2002-2003 Mark K. Kim
* All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   * Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*
*   * 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.
*
*   * Neither the original author of this software nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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 <stdio.h>
#include <stdlib.h>
#include <string.h>

class xgetopt
{
public:
    xgetopt(int argc_, char** argv_, const char* optstr_)
    {
        optarg = NULL;
        optind = 0;
        opterr = 1;
        optopt = '?';
        argv_index = 1;
        argv_index2 = 1;
        opt_offset = 1;
        dashdash = 0;
        nonopt = 0;
        argc = argc_;
        argv = argv_;
        optstr = optstr_;
        prev_argv = argv;
        prev_argc = argc;
    }
    int optind;
    int opterr;
    int optopt;
    
    int operator()()
    {
        int c = 0;
        /* Jump point in case we want to ignore the current argv_index */
        getopt_top:

        /* Misc. initializations */
        optarg = NULL;

        /* Dash-dash check */
        if(argv[argv_index] && !strcmp(argv[argv_index], "--"))
        {
            dashdash = 1;
            increment_index();
        }

        /* If we're at the end of argv, that's it. */
        if(argv[argv_index] == NULL)
        {
            c = -1;
        }
        /* Are we looking at a string? Single dash is also a string */
        else if(dashdash || argv[argv_index][0] != '-' || !strcmp(argv[argv_index], "-"))
        {
            /* If we want a string... */
            if(optstr[0] == '-')
            {
                c = 1;
                optarg = argv[argv_index];
                increment_index();
            }
            /* If we really don't want it (we're in POSIX mode), we're done */
            else if(optstr[0] == '+' || getenv("POSIXLY_CORRECT"))
            {
                c = -1;

                /* Everything else is a non-opt argument */
                nonopt = argc - argv_index;
            }
            /* If we mildly don't want it, then move it back */
            else
            {
                if(!permute_argv_once()) goto getopt_top;
                else c = -1;
            }
        }
        /* Otherwise we're looking at an option */
        else
        {
            const char* opt_ptr = NULL;

            /* Grab the option */
            c = argv[argv_index][opt_offset++];

            /* Is the option in the optstr? */
            if(optstr[0] == '-') opt_ptr = strchr(optstr+1, c);
            else opt_ptr = strchr(optstr, c);
            /* Invalid argument */
            if(!opt_ptr)
            {
                if(opterr)
                {
                    fprintf(stderr, "%s: invalid option -- %c\n", argv[0], c);
                }

                optopt = c;
                c = '?';

                /* Move onto the next option */
                increment_index();
            }
            /* Option takes argument */
            else if(opt_ptr[1] == ':')
            {
                /* ie, -oARGUMENT, -xxxoARGUMENT, etc. */
                if(argv[argv_index][opt_offset] != '\0')
                {
                    optarg = &argv[argv_index][opt_offset];
                    increment_index();
                }
                /* ie, -o ARGUMENT (only if it's a required argument) */
                else if(opt_ptr[2] != ':')
                {
                    /* One of those "you're not expected to understand this" moment */
                    if(argv_index2 < argv_index) argv_index2 = argv_index;
                    while(argv[++argv_index2] && argv[argv_index2][0] == '-');
                    optarg = argv[argv_index2];

                    /* Don't cross into the non-option argument list */
                    if(argv_index2 + nonopt >= prev_argc) optarg = NULL;

                    /* Move onto the next option */
                    increment_index();
                }
                else
                {
                    /* Move onto the next option */
                    increment_index();
                }

                /* In case we got no argument for an option with required argument */
                if(optarg == NULL && opt_ptr[2] != ':')
                {
                    optopt = c;
                    c = '?';

                    if(opterr)
                    {
                        fprintf(stderr,"%s: option requires an argument -- %c\n",
                                argv[0], optopt);
                    }
                }
            }
            /* Option does not take argument */
            else
            {
                /* Next argv_index */
                if(argv[argv_index][opt_offset] == '\0')
                {
                    increment_index();
                }
            }
        }

        /* Calculate optind */
        if(c == -1)
        {
            optind = argc - nonopt;
        }
        else
        {
            optind = argv_index;
        }

        return c;
    }

private:
    char** prev_argv;        /* Keep a copy of argv and argc to */
    int prev_argc;              /*    tell if getopt params change */
    int argv_index;             /* Option we're checking */
    int argv_index2;            /* Option argument we're checking */
    int opt_offset;             /* Index into compounded "-option" */
    int dashdash;               /* True if "--" option reached */
    int nonopt;                 /* How many nonopts we've found */
    int argc;
    char ** argv;
    const char * optstr;
    char* optarg;

    void increment_index()
    {
        /* Move onto the next option */
        if(argv_index < argv_index2)
        {
            while(prev_argv[++argv_index] && prev_argv[argv_index][0] != '-'
                    && argv_index < argv_index2+1);
        }
        else argv_index++;
        opt_offset = 1;
    }

    /*
    * Permutes argv[] so that the argument currently being processed is moved
    * to the end.
    */
    int permute_argv_once()
    {
        /* Movability check */
        if(argv_index + nonopt >= prev_argc) return 1;
        /* Move the current option to the end, bring the others to front */
        else
        {
            char* tmp = prev_argv[argv_index];

            /* Move the data */
            memmove(&prev_argv[argv_index], &prev_argv[argv_index+1],
                    sizeof(char**) * (prev_argc - argv_index - 1));
            prev_argv[prev_argc - 1] = tmp;

            nonopt++;
            return 0;
        }
    }
};