getopt.c

/*
 * getopt.c --
 *
 *      Standard UNIX getopt function.  Code is from BSD.
 *
 * Copyright (c) 1987-2002 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:
 *
 * A. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * B. 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.
 * C. Neither the names of the copyright holders 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 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.
 */

/* #if !defined(lint)
 * static char sccsid[] = "@(#)getopt.c 8.2 (Berkeley) 4/2/94";
 * #endif
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.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 */
    char *oli;                 /* option letter list index */

    if (optreset || !*place) { /* update scanning pointer */
	optreset = 0;
	if (optind >= nargc || *(place = nargv[optind]) != '-') {
	    place = EMSG;
	    return (EOF);
	}
	if (place[1] && *++place == '-') { /* found "--" */
	    ++optind;
	    place = EMSG;
	    return (EOF);
	}
    } /* option letter okay? */
    if ((optopt = (int)*place++) == (int)':' || !(oli = (char *)strchr(ostr, optopt))) {
	/*
	 * if the user didn't specify '-' as an option,
	 * assume it means EOF.
	 */
	if (optopt == (int)'-')
	    return (EOF);
	if (!*place)
	    ++optind;
	if (opterr && *ostr != ':')
	    (void)fprintf(stderr, "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)fprintf(stderr, "option requires an argument -- %c\n", optopt);
	    return (BADCH);
	}
	else /* white space */
	    optarg = nargv[optind];
	place = EMSG;
	++optind;
    }
    return (optopt); /* dump back option letter */
}