unix style getopt()

Author: Cameron Elliott

getopt.c

@@ -0,0 +1,108 @@
+
+#include "getopt.h" // make sure you construct the header file as dictated above
+
+/*
+* 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>
+
+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 */
+}
+

getopt.h

@@ -0,0 +1,10 @@
+// Put this in a separate .h file (called "getopt.h").
+// The prototype for the header file is:
+
+#ifndef GETOPT_H
+#define GETOPT_H
+
+int getopt(int nargc, char * const nargv[], const char *ostr) ;
+char    *optarg;
+#endif
+