Adds the bare minimum to respond to attempts to open NIB files with an Apple II.

Storage/Disk/DiskImage/Formats/NIB.cpp

@@ -0,0 +1,44 @@
+//
+//  NIB.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 21/04/2018.
+//  Copyright © 2018 Thomas Harte. All rights reserved.
+//
+
+#include "NIB.hpp"
+
+using namespace Storage::Disk;
+
+namespace {
+
+const std::size_t track_length = 6656;
+const std::size_t number_of_tracks = 35;
+
+}
+
+NIB::NIB(const std::string &file_name) :
+	file_(file_name) {
+	// A NIB should be 35 tracks, each 6656 bytes long.
+	if(file_.stats().st_size != track_length*number_of_tracks) {
+		throw ErrorNotNIB;
+	}
+
+	// TODO: all other validation.
+}
+
+int NIB::get_head_position_count() {
+	return 35;
+}
+
+int NIB::get_head_count() {
+	return 1;
+}
+
+bool NIB::get_is_read_only() {
+	return true;
+}
+
+std::shared_ptr<::Storage::Disk::Track> NIB::get_track_at_position(::Storage::Disk::Track::Address address) {
+	return nullptr;
+}