Adds a trivial mass-storage device, for Macintosh HFV volumes.

Storage/MassStorage/Formats/HFV.cpp

@@ -0,0 +1,33 @@
+//
+//  HFV.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 25/08/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "HFV.hpp"
+
+using namespace Storage::MassStorage;
+
+HFV::HFV(const std::string &file_name) : file_(file_name) {
+	// Is the file a multiple of 512 bytes in size and larger than a floppy disk?
+	const auto file_size = file_.stats().st_size;
+	if(file_size & 511 || file_size <= 800*1024) throw std::exception();
+
+	// TODO: check filing system for MFS, HFS or HFS+.
+}
+
+size_t HFV::get_block_size() {
+	return 512;
+}
+
+size_t HFV::get_number_of_blocks() {
+	return size_t(file_.stats().st_size) / get_block_size();
+}
+
+std::vector<uint8_t> HFV::get_block(size_t address) {
+	const long file_offset = long(get_block_size() * address);
+	file_.seek(file_offset, SEEK_SET);
+	return file_.read(get_block_size());
+}

Storage/MassStorage/Formats/HFV.hpp

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+//
+//  HFV.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 25/08/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef HFV_hpp
+#define HFV_hpp
+
+#include "../MassStorageDevice.hpp"
+#include "../../FileHolder.hpp"
+
+namespace Storage {
+namespace MassStorage {
+
+/*!
+	Provides a @c MassStorageDevice containing an HFV image, which is a sector dump of
+	a Macintosh drive that is not the correct size to be a floppy disk.
+*/
+class HFV: public MassStorageDevice {
+	public:
+		HFV(const std::string &file_name);
+
+	private:
+		FileHolder file_;
+
+		size_t get_block_size() final;
+		size_t get_number_of_blocks() final;
+		std::vector<uint8_t> get_block(size_t address) final;
+
+};
+
+}
+}
+
+#endif /* HFV_hpp */