getopt.c

Library and command line program for Huffman encoding and decoding both files and chunks of memory.

/*
 * getopt.c --
 *
 *      Standard UNIX getopt function.  Code is from BSD.
 *
 * Copyright (c) 1987-2001 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>

/* declarations to provide consistent linkage */
extern char *optarg;
extern int optind;
extern int opterr;

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 = 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,
			    "%s: illegal option -- %c\n", __FILE__, 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,
				    "%s: option requires an argument -- %c\n",
				    __FILE__, optopt);
			return (BADCH);
		}
	 	else				/* white space */
			optarg = nargv[optind];
		place = EMSG;
		++optind;
	}
	return (optopt);			/* dump back option letter */
}