getopt.c

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/*                        G E T O P T . C
 * BRL-CAD
 *
 * Copyright (c) 2004-2006 United States Government as represented by
 * the U.S. Army Research Laboratory.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this file; see the file named COPYING for more
 * information.
 */

/** \addtogroup getopt */
/*@{*/
/** @file getopt.c
 * @brief
 *  Special re-entrant version of getopt.
 *
 *  Everything is prefixed with bu_, to distinguish it from the various
 *  getopt() routines found in libc.
 *
 *  Important note -
 *      If bu_getopt() it going to be used more than once, it is necessary
 *      to reinitialize bu_optind=1 before beginning on the next argument list.
 */


#ifndef lint
static const char libbu_getopt_RCSid[] = "@(#)$Header: /cvsroot/brlcad/brlcad/src/libbu/getopt.c,v 14.11 2006/08/31 05:50:24 lbutler Exp $ (BRL)";
#endif

#include "common.h"

#include <stdio.h>
#ifdef HAVE_STRING_H
#  include <string.h>
#else
#  include <strings.h>
#endif

#include "machine.h"
#include "bu.h"


int     bu_opterr = 1;          /**< set to zero to suppress errors */
int     bu_optind = 1;          /**< index into parent argv vector */
int     bu_optopt = 0;          /**< character checked for validity */
char    *bu_optarg = NULL;      /**< argument associated with option */

#define BADCH   (int)'?'
#define EMSG    ""
#define tell(s) if(bu_opterr)  { \
                fputs(*nargv,stderr);fputs(s,stderr); \
                fputc(bu_optopt,stderr);fputc('\n',stderr); \
        } return(BADCH);


/**
 *                      B U _ G E T O P T
 *
 * get option letter from argument vector
 */
int
bu_getopt(int nargc, char *const *nargv, const char *ostr)
{
    static char *place = EMSG;  /* option letter processing */
    register char       *oli;           /* option letter list index */

    if(*place=='\0') {                  /* update scanning pointer */
        if(bu_optind >= nargc || *(place = nargv[bu_optind]) != '-' ||
           !*++place)  {
            place = EMSG;
            return(EOF);
        }
        if (*place == '-') {    /* found "--" */
            place = EMSG;
            ++bu_optind;
            return(EOF);
        }
    }                           /* option letter okay? */
    if ((bu_optopt = (int)*place++) == (int)':' || !(oli = strchr(ostr,bu_optopt))) {
#if 0
        if(*place == '\0') {
            ++bu_optind;
            place = EMSG;
        }
#else
        ++bu_optind;
        place = EMSG;
#endif
        tell(": illegal option -- ");
    }
    if (*++oli != ':') {                /* don't need argument */
        bu_optarg = NULL;
        if (*place == '\0') {
            ++bu_optind;
            place = EMSG;
        }
    }
    else {                              /* need an argument */
        if (*place) bu_optarg = place;  /* no white space */
        else if (nargc <= ++bu_optind) {        /* no arg */
            place = EMSG;
            tell(": option requires an argument -- ");
        }
        else bu_optarg = nargv[bu_optind];      /* white space */
        place = EMSG;
        ++bu_optind;
    }
    return(bu_optopt);                  /* dump back option letter */
}
/*@}*/
/*
 * Local Variables:
 * mode: C
 * tab-width: 8
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 * ex: shiftwidth=4 tabstop=8
 */

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