text: /*
  * Copyright (c) 1987, 1993, 1994
  *      The Regents of the University of California.  All rights reserved.
  *
  * 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.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *      This product includes software developed by the University of
  *      California, Berkeley and its contributors.
  * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 <string.h>
  #include <stdio.h>
  
  #include "getopt.h"
  
  int     opterr = 1,             /* if error message should be printed */
          optind = 1,             /* index into parent argv vector */
          optopt,                 /* character checked for validity */
          optreset;               /* reset getopt */
  char    *optarg;                /* argument associated with option */
  
  #define BADCH   (int)'?'
  #define BADARG  (int)':'
  #define EMSG    ""
  
  /*
   * getopt --
   *      Parse argc/argv argument vector.
   */
  int getopt(int nargc, char * const nargv[], const char *ostr)
  {
    static char *place = EMSG;              /* option letter processing */
    const char *oli;                              /* option letter list index */
  
    if (optreset || !*place) {              /* update scanning pointer */
      optreset = 0;
      if (optind >= nargc || *(place = nargv[optind]) != '-') {
        place = EMSG;
        return (-1);
      }
      if (place[1] && *++place == '-') {      /* found "--" */
        ++optind;
        place = EMSG;
        return (-1);
      }
    }                                       /* option letter okay? */
    if ((optopt = (int)*place++) == (int)':' ||
      !(oli = strchr(ostr, optopt))) {
        /*
        * if the user didn't specify '-' as an option,
        * assume it means -1.
        */
        if (optopt == (int)'-')
          return (-1);
        if (!*place)
          ++optind;
        if (opterr && *ostr != ':')
          (void)printf("illegal option -- %c\n", optopt);
        return (BADCH);
    }
    if (*++oli != ':') {                    /* don't need argument */
      optarg = NULL;
      if (!*place)
        ++optind;
    }
    else {                                  /* need an argument */
      if (*place)                     /* no white space */
        optarg = place;
      else if (nargc <= ++optind) {   /* no arg */
        place = EMSG;
        if (*ostr == ':')
          return (BADARG);
        if (opterr)
          (void)printf("option requires an argument -- %c\n", optopt);
        return (BADCH);
      }
      else                            /* white space */
        optarg = nargv[optind];
      place = EMSG;
      ++optind;
    }
    return (optopt);                        /* dump back option letter */
  }
  