From e11de8814424c2abb61d91a050e1096d17765787 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sat, 14 Dec 2024 03:55:02 -0500
Subject: Add getopt.c (ancient but public domain).

---
 getopt.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 getopt.c

diff --git a/getopt.c b/getopt.c
new file mode 100644
index 0000000..c6bf394
--- /dev/null
+++ b/getopt.c
@@ -0,0 +1,96 @@
+/* 20070425 bkw:
+	Public Domain implementation of getopt(),
+	downloaded from http://www.zdomain.com/a56/src/getopt.c
+	Following anonymous comment was in the original version:
+*/
+
+/*
+	I got this off net.sources from Henry Spencer.
+	It is a public domain getopt(3) like in System V.
+	I have made the following modifications:
+
+	index(s,c) was added because too many people could
+	not compile getopt without it.
+
+	A test main program was added, ifdeffed by GETOPT.
+	This main program is a public domain implementation
+	of the getopt(1) program like in System V.  The getopt
+	program can be used to standardize shell option handling.
+		e.g.  cc -DGETOPT getopt.c -o getopt
+*/
+
+/* 20070425 bkw:
+	Altered slightly for cassio (use fatal() for error messages,
+	get rid of main(), add return type to getopt()...)
+*/
+
+/* 20241214 bkw: modified slightly for use with uxd. */
+
+extern char *self;
+
+#include <stdio.h>
+
+#define	ARGCH    (int)':'
+#define BADCH	 (int)'?'
+#define EMSG	 ""
+#define	ENDARGS  "--"
+
+/* this is included because index is not on some UNIX systems */
+static
+char *
+index (s, c)
+register	char	*s;
+register	int 	c;
+	{
+	while (*s)
+		if (c == *s) return (s);
+		else s++;
+	return (NULL);
+	}
+
+/*
+ * get option letter from argument vector
+ */
+int	opterr = 1,		/* useless, never set or used */
+	optind = 1,		/* index into parent argv vector */
+	optopt;			/* character checked for validity */
+char	*optarg;		/* argument associated with option */
+
+#define tell(s)	fprintf(stderr, "%s: %s", self, s); \
+		fputc(optopt,stderr);fputs(" (use -h for help)\n",stderr);return(BADCH);
+
+
+int getopt(int nargc, char **nargv, char *ostr)
+{
+	static char	*place = EMSG;	/* option letter processing */
+	register char	*oli;		/* option letter list index */
+	char	*index();
+
+	if(!*place) {			/* update scanning pointer */
+		if(optind >= nargc || *(place = nargv[optind]) != '-' || !*++place) return(EOF);
+		if (*place == '-') {	/* found "--" */
+			++optind;
+			return(EOF);
+		}
+	}				/* option letter okay? */
+	if ((optopt = (int)*place++) == ARGCH || !(oli = index(ostr,optopt))) {
+		if(!*place) ++optind;
+		tell("illegal option: -");
+	}
+	if (*++oli != ARGCH) {		/* don't need argument */
+		optarg = NULL;
+		if (!*place) ++optind;
+	}
+	else {				/* need an argument */
+		if (*place) optarg = place;	/* no white space */
+		else if (nargc <= ++optind) {	/* no arg */
+			place = EMSG;
+			tell("option requires an argument: -");
+		}
+	 	else optarg = nargv[optind];	/* white space */
+		place = EMSG;
+		++optind;
+	}
+	return(optopt);			/* dump back option letter */
+}
+
-- 
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