Factors out boilerplate around full-device sector images.

Storage/MassStorage/Formats/DAT.cpp

@@ -10,32 +10,13 @@
 
 using namespace Storage::MassStorage;
 
-DAT::DAT(const std::string &file_name) : file_(file_name) {
-	// Is the file a multiple of 256 bytes in size?
-	const auto file_size = file_.stats().st_size;
-	if(file_size & 255) throw std::exception();
-
-	// Does it contain the 'Hugo' signature?
-	file_.seek(0x201, SEEK_SET);
-	if(!file_.check_signature("Hugo")) {
+DAT::DAT(const std::string &file_name) : RawSectorDump(file_name) {
+	// Does the third sector contain the 'Hugo' signature?
+	const auto sector3 = get_block(2);
+	if(sector3.size() != 256) {
+		throw std::exception();
+	}
+	if(sector3[1] != 'H' || sector3[2] != 'u' || sector3[3] != 'g' || sector3[4] != 'o') {
 		throw std::exception();
 	}
 }
-
-size_t DAT::get_block_size() {
-	return 256;
-}
-
-size_t DAT::get_number_of_blocks() {
-	return size_t(file_.stats().st_size) / 256;
-}
-
-std::vector<uint8_t> DAT::get_block(size_t address) {
-	file_.seek(long(address * 256), SEEK_SET);
-	return file_.read(256);
-}
-
-void DAT::set_block(size_t address, const std::vector<uint8_t> &contents) {
-	file_.seek(long(address * 256), SEEK_SET);
-	file_.write(contents);
-}

Storage/MassStorage/Formats/DAT.hpp

@@ -9,8 +9,7 @@
 #ifndef MassStorage_DAT_hpp
 #define MassStorage_DAT_hpp
 
-#include "../MassStorageDevice.hpp"
-#include "../../FileHolder.hpp"
+#include "RawSectorDump.hpp"
 
 namespace Storage {
 namespace MassStorage {
@@ -20,18 +19,9 @@ namespace MassStorage {
 	sector dump of an ADFS volume. It will be validated for an ADFS catalogue and communicate
 	in 256-byte blocks.
 */
-class DAT: public MassStorageDevice {
+class DAT: public RawSectorDump<256> {
 	public:
 		DAT(const std::string &file_name);
-
-	private:
-		FileHolder file_;
-
-		/* MassStorageDevices overrides. */
-		size_t get_block_size() final;
-		size_t get_number_of_blocks() final;
-		std::vector<uint8_t> get_block(size_t address) final;
-		void set_block(size_t address, const std::vector<uint8_t> &) final;
 };
 
 }

Storage/MassStorage/Formats/RawSectorDump.hpp

@@ -0,0 +1,53 @@
+//
+//  RawSectorDump.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 01/05/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef RawSectorDump_h
+#define RawSectorDump_h
+
+#include "../MassStorageDevice.hpp"
+#include "../../FileHolder.hpp"
+
+namespace Storage {
+namespace MassStorage {
+
+template <size_t sector_size> class RawSectorDump: public MassStorageDevice {
+	public:
+		RawSectorDump(const std::string &file_name) : file_(file_name) {
+			// Is the file a multiple of sector_size bytes in size?
+			const auto file_size = size_t(file_.stats().st_size);
+			if(file_size % sector_size) throw std::exception();
+		}
+
+		/* MassStorageDevices overrides. */
+		size_t get_block_size() final {
+			return sector_size;
+		}
+
+		size_t get_number_of_blocks() final {
+			return size_t(file_.stats().st_size) / sector_size;
+		}
+
+		std::vector<uint8_t> get_block(size_t address) final {
+			file_.seek(long(address * sector_size), SEEK_SET);
+			return file_.read(sector_size);
+		}
+
+		void set_block(size_t address, const std::vector<uint8_t> &contents) final {
+			assert(contents.size() == sector_size);
+			file_.seek(long(address * sector_size), SEEK_SET);
+			file_.write(contents);
+		}
+
+	private:
+		FileHolder file_;
+};
+
+}
+}
+
+#endif /* RawSectorDump_h */