/*****************************************************************************
* getopt.c - competent and free getopt library.
* $Header: /home/doj/code/tr2latex/getopt.c,v 1.1 2012-09-02 04:52:22 doj 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>
#include "getopt.h"

char* optarg = NULL;
int optind = 0;
int opterr = 1;
int optopt = '?';

static char** prev_argv = NULL;        /* Keep a copy of argv and argc to */
static int prev_argc = 0;              /*    tell if getopt params change */
static int argv_index = 0;             /* Option we're checking */
static int argv_index2 = 0;            /* Option argument we're checking */
static int opt_offset = 0;             /* Index into compounded "-option" */
static int dashdash = 0;               /* True if "--" option reached */
static int nonopt = 0;                 /* How many nonopts we've found */

static 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.
*/
static 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;
       }
}

int getopt(int argc, char** argv, char* optstr)
{
       int c = 0;

       /* If we have new argv, reinitialize */
       if(prev_argv != argv || prev_argc != argc)
       {
               /* Initialize variables */
               prev_argv = argv;
               prev_argc = argc;
               argv_index = 1;
               argv_index2 = 1;
               opt_offset = 1;
               dashdash = 0;
               nonopt = 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
       {
               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;
}

/* vim:ts=3
*/