--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/target-utils/simagent/stringarg.c	Fri Mar 12 23:36:46 2021 +0000
@@ -0,0 +1,43 @@
+/*
+ * This module contains the function that parses our hex string arguments.
+ */
+
+#include <ctype.h>
+#include "types.h"
+
+static
+decode_hex_digit(c)
+{
+	if (isdigit(c))
+		return c - '0';
+	else if (islower(c))
+		return c - 'a' + 10;
+	else
+		return c - 'A' + 10;
+}
+
+decode_hex_string_arg(arg, buf, maxlen)
+	char *arg;
+	u8 *buf;
+	unsigned maxlen;
+{
+	unsigned count;
+
+	for (count = 0; ; ) {
+		while (isspace(*arg))
+			arg++;
+		if (!*arg)
+			break;
+		if (!isxdigit(arg[0]) || !isxdigit(arg[1])) {
+			printf("ERROR: invalid hex string input\n");
+			return;
+		}
+		if (count >= maxlen) {
+			printf("ERROR: hex string input is too long\n");
+			return;
+		}
+		buf[count++] = (decode_hex_digit(arg[0]) << 4) |
+				decode_hex_digit(arg[1]);
+	}
+	return count;
+}