Add file ares_getopt.c

Original file name getopt.c  Initial import into the c-ares source tree
on 2007-04-11.  Lifted from version 5.2 of the 'Open Mash' project with
the modified BSD license, BSD license without the advertising clause.

ares/ares_getopt.c

+/*
+ * Original file name getopt.c  Initial import into the c-ares source tree
+ * on 2007-04-11.  Lifted from version 5.2 of the 'Open Mash' project with
+ * the modified BSD license, BSD license without the advertising clause.
+ *
+ * $Id$
+ */
+
+/*
+ * 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(nargc, nargv, ostr)
+	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 */
+}