This is going to be a slow walk, I think. This class attempts to be the scratchpad which will hold in-memory track modifications.

Storage/Disk/PCMPatchedTrack.cpp

@@ -0,0 +1,16 @@
+//
+//  PCMPatchedTrack.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 15/12/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+#include "PCMPatchedTrack.hpp"
+
+using namespace Storage::Disk;
+
+void PCMPatchedTrack::add_segment(const Time &start_position, const PCMSegment &segment)
+{
+	patches_.emplace_back(start_position, segment);
+}