Finally unifies disk image file exceptions, and adds a placeholder for Apple DSK.

Analyser/Static/StaticAnalyser.cpp

@@ -30,6 +30,7 @@
 
 // Disks
 #include "../../Storage/Disk/DiskImage/Formats/AcornADF.hpp"
+#include "../../Storage/Disk/DiskImage/Formats/AppleDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/CPCDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/D64.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/G64.hpp"
@@ -95,6 +96,7 @@ static Media GetMediaAndPlatforms(const std::string &file_name, TargetPlatform::
 	Format("dmk", result.disks, Disk::DiskImageHolder<Storage::Disk::DMK>, TargetPlatform::MSX)				// DMK
 	Format("dsd", result.disks, Disk::DiskImageHolder<Storage::Disk::SSD>, TargetPlatform::Acorn)			// DSD
 	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::CPCDSK>, TargetPlatform::AmstradCPC)	// DSK (Amstrad CPC)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::AppleII)	// DSK (Apple)
 	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MSXDSK>, TargetPlatform::MSX)			// DSK (MSX)
 	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::OricMFMDSK>, TargetPlatform::Oric)		// DSK (Oric)
 	Format("g64", result.disks, Disk::DiskImageHolder<Storage::Disk::G64>, TargetPlatform::Commodore)		// G64

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -8,6 +8,8 @@
 
 /* Begin PBXBuildFile section */
 		4B01A6881F22F0DB001FD6E3 /* Z80MemptrTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */; };
+		4B0333AF2094081A0050B93D /* AppleDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0333AD2094081A0050B93D /* AppleDSK.cpp */; };
+		4B0333B02094081A0050B93D /* AppleDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0333AD2094081A0050B93D /* AppleDSK.cpp */; };
 		4B049CDD1DA3C82F00322067 /* BCDTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B049CDC1DA3C82F00322067 /* BCDTest.swift */; };
 		4B055A7A1FAE78A00060FFFF /* SDL2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B055A771FAE78210060FFFF /* SDL2.framework */; };
 		4B055A7E1FAE84AA0060FFFF /* main.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B055A7C1FAE84A50060FFFF /* main.cpp */; };
@@ -680,6 +682,8 @@
 
 /* Begin PBXFileReference section */
 		4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Z80MemptrTests.swift; sourceTree = "<group>"; };
+		4B0333AD2094081A0050B93D /* AppleDSK.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = AppleDSK.cpp; sourceTree = "<group>"; };
+		4B0333AE2094081A0050B93D /* AppleDSK.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = AppleDSK.hpp; sourceTree = "<group>"; };
 		4B046DC31CFE651500E9E45E /* CRTMachine.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CRTMachine.hpp; sourceTree = "<group>"; };
 		4B047075201ABC180047AB0D /* Cartridge.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Cartridge.hpp; sourceTree = "<group>"; };
 		4B049CDC1DA3C82F00322067 /* BCDTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = BCDTest.swift; sourceTree = "<group>"; };
@@ -1869,6 +1873,7 @@
 			isa = PBXGroup;
 			children = (
 				4B45188D1F75FD1B00926311 /* AcornADF.cpp */,
+				4B0333AD2094081A0050B93D /* AppleDSK.cpp */,
 				4B45188F1F75FD1B00926311 /* CPCDSK.cpp */,
 				4B4518911F75FD1B00926311 /* D64.cpp */,
 				4BAF2B4C2004580C00480230 /* DMK.cpp */,
@@ -1879,7 +1884,9 @@
 				4B0F94FC208C1A1600FE41D9 /* NIB.cpp */,
 				4B4518971F75FD1B00926311 /* OricMFMDSK.cpp */,
 				4B4518991F75FD1B00926311 /* SSD.cpp */,
+				4B6ED2EE208E2F8A0047B343 /* WOZ.cpp */,
 				4B45188E1F75FD1B00926311 /* AcornADF.hpp */,
+				4B0333AE2094081A0050B93D /* AppleDSK.hpp */,
 				4B4518901F75FD1B00926311 /* CPCDSK.hpp */,
 				4B4518921F75FD1B00926311 /* D64.hpp */,
 				4BAF2B4D2004580C00480230 /* DMK.hpp */,
@@ -1890,9 +1897,8 @@
 				4B0F94FD208C1A1600FE41D9 /* NIB.hpp */,
 				4B4518981F75FD1B00926311 /* OricMFMDSK.hpp */,
 				4B45189A1F75FD1B00926311 /* SSD.hpp */,
-				4BFDD7891F7F2DB4008579B9 /* Utility */,
-				4B6ED2EE208E2F8A0047B343 /* WOZ.cpp */,
 				4B6ED2EF208E2F8A0047B343 /* WOZ.hpp */,
+				4BFDD7891F7F2DB4008579B9 /* Utility */,
 			);
 			path = Formats;
 			sourceTree = "<group>";
@@ -3650,6 +3656,7 @@
 				4BAF2B4F2004580C00480230 /* DMK.cpp in Sources */,
 				4B055AD01FAE9B030060FFFF /* Tape.cpp in Sources */,
 				4B055A961FAE85BB0060FFFF /* Commodore.cpp in Sources */,
+				4B0333B02094081A0050B93D /* AppleDSK.cpp in Sources */,
 				4B055ADE1FAE9B4C0060FFFF /* 6522Base.cpp in Sources */,
 				4B894535201967B4007DE474 /* AddressMapper.cpp in Sources */,
 				4B055AD41FAE9B0B0060FFFF /* Oric.cpp in Sources */,
@@ -3727,6 +3734,7 @@
 				4BBFFEE61F7B27F1005F3FEB /* TrackSerialiser.cpp in Sources */,
 				4BAE49582032881E004BE78E /* CSZX8081.mm in Sources */,
 				4BC3B74F1CD194CC00F86E85 /* Shader.cpp in Sources */,
+				4B0333AF2094081A0050B93D /* AppleDSK.cpp in Sources */,
 				4B894518201967B4007DE474 /* ConfidenceCounter.cpp in Sources */,
 				4B89452E201967B4007DE474 /* StaticAnalyser.cpp in Sources */,
 				4B38F3481F2EC11D00D9235D /* AmstradCPC.cpp in Sources */,

Storage/Disk/DiskImage/DiskImage.hpp

@@ -18,6 +18,11 @@
 namespace Storage {
 namespace Disk {
 
+enum class Error {
+	InvalidFormat = -2,
+	UnknownVersion = -3
+};
+
 /*!
 	Models a disk image as a collection of tracks, plus a range of possible track positions.
 

Storage/Disk/DiskImage/Formats/AcornADF.cpp

@@ -20,18 +20,18 @@ using namespace Storage::Disk;
 AcornADF::AcornADF(const std::string &file_name) : MFMSectorDump(file_name) {
 	// very loose validation: the file needs to be a multiple of 256 bytes
 	// and not ungainly large
-	if(file_.stats().st_size % static_cast<off_t>(128 << sector_size)) throw ErrorNotAcornADF;
-	if(file_.stats().st_size < 7 * static_cast<off_t>(128 << sector_size)) throw ErrorNotAcornADF;
+	if(file_.stats().st_size % static_cast<off_t>(128 << sector_size)) throw Error::InvalidFormat;
+	if(file_.stats().st_size < 7 * static_cast<off_t>(128 << sector_size)) throw Error::InvalidFormat;
 
 	// check that the initial directory's 'Hugo's are present
 	file_.seek(513, SEEK_SET);
 	uint8_t bytes[4];
 	file_.read(bytes, 4);
-	if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw ErrorNotAcornADF;
+	if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw Error::InvalidFormat;
 
 	file_.seek(0x6fb, SEEK_SET);
 	file_.read(bytes, 4);
-	if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw ErrorNotAcornADF;
+	if(bytes[0] != 'H' || bytes[1] != 'u' || bytes[2] != 'g' || bytes[3] != 'o') throw Error::InvalidFormat;
 
 	set_geometry(sectors_per_track, sector_size, 0, true);
 }

Storage/Disk/DiskImage/Formats/AcornADF.hpp

@@ -24,15 +24,11 @@ class AcornADF: public MFMSectorDump {
 		/*!
 			Construct an @c AcornADF containing content from the file with name @c file_name.
 
-			@throws ErrorCantOpen if this file can't be opened.
-			@throws ErrorNotAcornADF if the file doesn't appear to contain an Acorn .ADF format image.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain an Acorn .ADF format image.
 		*/
 		AcornADF(const std::string &file_name);
 
-		enum {
-			ErrorNotAcornADF,
-		};
-
 		int get_head_position_count() override;
 		int get_head_count() override;
 

Storage/Disk/DiskImage/Formats/AppleDSK.cpp

@@ -0,0 +1,37 @@
+//
+//  AppleDSK.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 27/04/2018.
+//  Copyright © 2018 Thomas Harte. All rights reserved.
+//
+
+#include "AppleDSK.hpp"
+
+using namespace Storage::Disk;
+
+namespace {
+	const int number_of_tracks = 35;
+	const int bytes_per_sector = 256;
+}
+
+AppleDSK::AppleDSK(const std::string &file_name) :
+	file_(file_name) {
+	if(file_.stats().st_size % number_of_tracks*bytes_per_sector) throw Error::InvalidFormat;
+
+	sectors_per_track_ = static_cast<int>(file_.stats().st_size / (number_of_tracks*bytes_per_sector));
+	if(sectors_per_track_ != 13 && sectors_per_track_ != 16) throw Error::InvalidFormat;
+}
+
+int AppleDSK::get_head_position_count() {
+	return number_of_tracks * 4;
+}
+
+std::shared_ptr<Track> AppleDSK::get_track_at_position(Track::Address address) {
+	const long file_offset = (address.position >> 2) * bytes_per_sector * sectors_per_track_;
+	file_.seek(file_offset, SEEK_SET);
+
+//	std::vector<uint8_t> track_data = file_.read(bytes_per_sector * sectors_per_track_);
+
+	return nullptr;
+}

Storage/Disk/DiskImage/Formats/AppleDSK.hpp

@@ -0,0 +1,47 @@
+//
+//  AppleDSK.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 27/04/2018.
+//  Copyright © 2018 Thomas Harte. All rights reserved.
+//
+
+#ifndef AppleDSK_hpp
+#define AppleDSK_hpp
+
+#include "../DiskImage.hpp"
+#include "../../../FileHolder.hpp"
+
+#include <string>
+
+namespace Storage {
+namespace Disk {
+
+/*!
+	Provides a @c DiskImage containing an Apple DSK disk image — a representation of sector contents,
+	implicitly numbered and located.
+*/
+class AppleDSK: public DiskImage {
+	public:
+		/*!
+			Construct an @c AppleDSK containing content from the file with name @c file_name.
+
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain a .G64 format image.
+		*/
+		AppleDSK(const std::string &file_name);
+
+		// implemented to satisfy @c Disk
+		int get_head_position_count() override;
+		std::shared_ptr<Track> get_track_at_position(Track::Address address) override;
+
+	private:
+		Storage::FileHolder file_;
+		int sectors_per_track_;
+};
+
+}
+}
+
+
+#endif /* AppleDSK_hpp */

Storage/Disk/DiskImage/Formats/CPCDSK.cpp

@@ -27,7 +27,7 @@ CPCDSK::CPCDSK(const std::string &file_name) :
 		is_extended_ = true;
 		file.seek(0, SEEK_SET);
 		if(!file.check_signature("EXTENDED"))
-			throw ErrorNotCPCDSK;
+			throw Error::InvalidFormat;
 	}
 
 	// Don't really care about about the creator; skip.
@@ -145,7 +145,7 @@ CPCDSK::CPCDSK(const std::string &file_name) :
 						if(declared_data_size > data_size) {
 							number_of_samplings = declared_data_size / data_size;
 							if(declared_data_size % data_size)
-								throw ErrorNotCPCDSK;
+								throw Error::InvalidFormat;
 						} else {
 							stored_data_size = declared_data_size;
 						}

Storage/Disk/DiskImage/Formats/CPCDSK.hpp

@@ -27,15 +27,11 @@ class CPCDSK: public DiskImage {
 		/*!
 			Construct an @c AcornADF containing content from the file with name @c file_name.
 
-			@throws ErrorCantOpen if this file can't be opened.
-			@throws ErrorNotAcornADF if the file doesn't appear to contain an Acorn .ADF format image.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain an Acorn .ADF format image.
 		*/
 		CPCDSK(const std::string &file_name);
 
-		enum {
-			ErrorNotCPCDSK,
-		};
-
 		// implemented to satisfy @c Disk
 		int get_head_position_count() override;
 		int get_head_count() override;

Storage/Disk/DiskImage/Formats/D64.cpp

@@ -22,7 +22,7 @@ D64::D64(const std::string &file_name) :
 	// in D64, this is it for validation without imposing potential false-negative tests — check that
 	// the file size appears to be correct. Stone-age stuff.
 	if(file_.stats().st_size != 174848 && file_.stats().st_size != 196608)
-		throw ErrorNotD64;
+		throw Error::InvalidFormat;
 
 	number_of_tracks_ = (file_.stats().st_size == 174848) ? 35 : 40;
 

Storage/Disk/DiskImage/Formats/D64.hpp

@@ -23,15 +23,11 @@ class D64: public DiskImage {
 		/*!
 			Construct a @c D64 containing content from the file with name @c file_name.
 
-			@throws ErrorCantOpen if this file can't be opened.
-			@throws ErrorNotD64 if the file doesn't appear to contain a .D64 format image.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain a .D64 format image.
 		*/
 		D64(const std::string &file_name);
 
-		enum {
-			ErrorNotD64,
-		};
-
 		// implemented to satisfy @c Disk
 		int get_head_position_count() override;
 		using DiskImage::get_is_read_only;

Storage/Disk/DiskImage/Formats/DMK.cpp

@@ -35,9 +35,9 @@ std::unique_ptr<Storage::Encodings::MFM::Encoder> new_encoder(Storage::Disk::PCM
 DMK::DMK(const std::string &file_name) :
 	file_(file_name) {
 	// Determine whether this DMK represents a read-only disk (whether intentionally,
-	// or by virtue of placement).
+	// or by virtue of filesystem placement).
 	uint8_t read_only_byte = file_.get8();
-	if(read_only_byte != 0x00 && read_only_byte != 0xff) throw ErrorNotDMK;
+	if(read_only_byte != 0x00 && read_only_byte != 0xff) throw Error::InvalidFormat;
 	is_read_only_ = (read_only_byte == 0xff) || file_.get_is_known_read_only();
 
 	// Read track count and size.
@@ -46,7 +46,7 @@ DMK::DMK(const std::string &file_name) :
 
 	// Track length must be at least 0x80, as that's the size of the IDAM
 	// table before track contents.
-	if(track_length_ < 0x80) throw ErrorNotDMK;
+	if(track_length_ < 0x80) throw Error::InvalidFormat;
 
 	// Read the file flags and apply them.
 	uint8_t flags = file_.get8();
@@ -58,7 +58,7 @@ DMK::DMK(const std::string &file_name) :
 	// "in the emulator's native format".
 	file_.seek(0xc, SEEK_SET);
 	uint32_t format = file_.get32le();
-	if(format) throw ErrorNotDMK;
+	if(format) throw Error::InvalidFormat;
 }
 
 int DMK::get_head_position_count() {

Storage/Disk/DiskImage/Formats/DMK.hpp

@@ -26,14 +26,10 @@ class DMK: public DiskImage {
 		/*!
 			Construct a @c DMK containing content from the file with name @c file_name.
 
-			@throws ErrorNotDMK if this file doesn't appear to be a DMK.
+			@throws Error::InvalidFormat if this file doesn't appear to be a DMK.
 		*/
 		DMK(const std::string &file_name);
 
-		enum {
-			ErrorNotDMK
-		};
-
 		// implemented to satisfy @c Disk
 		int get_head_position_count() override;
 		int get_head_count() override;

Storage/Disk/DiskImage/Formats/G64.cpp

@@ -19,11 +19,11 @@ using namespace Storage::Disk;
 G64::G64(const std::string &file_name) :
 		file_(file_name) {
 	// read and check the file signature
-	if(!file_.check_signature("GCR-1541")) throw ErrorNotG64;
+	if(!file_.check_signature("GCR-1541")) throw Error::InvalidFormat;
 
 	// check the version number
 	int version = file_.get8();
-	if(version != 0) throw ErrorUnknownVersion;
+	if(version != 0) throw Error::UnknownVersion;
 
 	// get the number of tracks and track size
 	number_of_tracks_ = file_.get8();

Storage/Disk/DiskImage/Formats/G64.hpp

@@ -25,18 +25,12 @@ class G64: public DiskImage {
 		/*!
 			Construct a @c G64 containing content from the file with name @c file_name.
 
-			@throws ErrorCantOpen if this file can't be opened.
-			@throws ErrorNotG64 if the file doesn't appear to contain a .G64 format image.
-			@throws ErrorUnknownVersion if this file appears to be a .G64 but has an unrecognised version number.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain a .G64 format image.
+			@throws Error::UnknownVersion if this file appears to be a .G64 but has an unrecognised version number.
 		*/
 		G64(const std::string &file_name);
 
-		enum {
-			ErrorCantOpen,
-			ErrorNotG64,
-			ErrorUnknownVersion
-		};
-
 		// implemented to satisfy @c Disk
 		int get_head_position_count() override;
 		std::shared_ptr<Track> get_track_at_position(Track::Address address) override;

Storage/Disk/DiskImage/Formats/HFE.cpp

@@ -16,9 +16,9 @@ using namespace Storage::Disk;
 
 HFE::HFE(const std::string &file_name) :
 		file_(file_name) {
-	if(!file_.check_signature("HXCPICFE")) throw ErrorNotHFE;
+	if(!file_.check_signature("HXCPICFE")) throw Error::InvalidFormat;
 
-	if(file_.get8()) throw ErrorNotHFE;
+	if(file_.get8()) throw Error::UnknownVersion;
 	track_count_ = file_.get8();
 	head_count_ = file_.get8();
 

Storage/Disk/DiskImage/Formats/HFE.hpp

@@ -25,15 +25,13 @@ class HFE: public DiskImage {
 		/*!
 			Construct an @c HFE containing content from the file with name @c file_name.
 
-			@throws ErrorNotHFE if the file doesn't appear to contain a .SSD format image.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain an .HFE format image.
+			@throws Error::UnknownVersion if the file looks correct but is an unsupported version.
 		*/
 		HFE(const std::string &file_name);
 		~HFE();
 
-		enum {
-			ErrorNotHFE
-		};
-
 		// implemented to satisfy @c Disk
 		int get_head_position_count() override;
 		int get_head_count() override;

Storage/Disk/DiskImage/Formats/MSXDSK.cpp

@@ -25,16 +25,16 @@ MSXDSK::MSXDSK(const std::string &file_name) :
 	off_t file_size = file_.stats().st_size;
 
 	// Throw if there would seemingly be an incomplete track.
-	if(file_size % track_size) throw ErrorNotMSXDSK;
+	if(file_size % track_size) throw Error::InvalidFormat;
 
 	track_count_ = static_cast<int>(file_size / track_size);
 	head_count_ = 1;
 
 	// Throw if too large or too small or too large for single sided and
 	// clearly not double sided.
-	if(track_count_ < 40) throw ErrorNotMSXDSK;
-	if(track_count_ > 82*2) throw ErrorNotMSXDSK;
-	if(track_count_ > 82 && track_count_&1) throw ErrorNotMSXDSK;
+	if(track_count_ < 40) throw Error::InvalidFormat;
+	if(track_count_ > 82*2) throw Error::InvalidFormat;
+	if(track_count_ > 82 && track_count_&1) throw Error::InvalidFormat;
 
 	// The below effectively prefers the idea of a single-sided 80-track disk
 	// to a double-sided 40-track disk. Emulators have to guess.

Storage/Disk/DiskImage/Formats/MSXDSK.hpp

@@ -23,11 +23,6 @@ namespace Disk {
 class MSXDSK: public MFMSectorDump {
 	public:
 		MSXDSK(const std::string &file_name);
-
-		enum {
-			ErrorNotMSXDSK,
-		};
-
 		int get_head_position_count() override;
 		int get_head_count() override;
 

Storage/Disk/DiskImage/Formats/NIB.cpp

@@ -26,7 +26,7 @@ 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;
+		throw Error::InvalidFormat;
 	}
 
 	// TODO: all other validation. I.e. does this look like a GCR disk?

Storage/Disk/DiskImage/Formats/NIB.hpp

@@ -24,10 +24,6 @@ class NIB: public DiskImage {
 	public:
 		NIB(const std::string &file_name);
 
-		enum {
-			ErrorNotNIB,
-		};
-
 		int get_head_position_count() override;
 
 		std::shared_ptr<::Storage::Disk::Track> get_track_at_position(::Storage::Disk::Track::Address address) override;

Storage/Disk/DiskImage/Formats/OricMFMDSK.cpp

@@ -19,14 +19,14 @@ using namespace Storage::Disk;
 OricMFMDSK::OricMFMDSK(const std::string &file_name) :
 		file_(file_name) {
 	if(!file_.check_signature("MFM_DISK"))
-		throw ErrorNotOricMFMDSK;
+		throw Error::InvalidFormat;
 
 	head_count_ = file_.get32le();
 	track_count_ = file_.get32le();
 	geometry_type_ = file_.get32le();
 
 	if(geometry_type_ < 1 || geometry_type_ > 2)
-		throw ErrorNotOricMFMDSK;
+		throw Error::InvalidFormat;
 }
 
 int OricMFMDSK::get_head_position_count() {

Storage/Disk/DiskImage/Formats/OricMFMDSK.hpp

@@ -29,10 +29,6 @@ class OricMFMDSK: public DiskImage {
 		*/
 		OricMFMDSK(const std::string &file_name);
 
-		enum {
-			ErrorNotOricMFMDSK,
-		};
-
 		// implemented to satisfy @c DiskImage
 		int get_head_position_count() override;
 		int get_head_count() override;

Storage/Disk/DiskImage/Formats/SSD.cpp

@@ -23,9 +23,9 @@ SSD::SSD(const std::string &file_name) : MFMSectorDump(file_name) {
 	// very loose validation: the file needs to be a multiple of 256 bytes
 	// and not ungainly large
 
-	if(file_.stats().st_size & 255) throw ErrorNotSSD;
-	if(file_.stats().st_size < 512) throw ErrorNotSSD;
-	if(file_.stats().st_size > 800*256) throw ErrorNotSSD;
+	if(file_.stats().st_size & 255) throw Error::InvalidFormat;
+	if(file_.stats().st_size < 512) throw Error::InvalidFormat;
+	if(file_.stats().st_size > 800*256) throw Error::InvalidFormat;
 
 	// this has two heads if the suffix is .dsd, one if it's .ssd
 	head_count_ = (tolower(file_name[file_name.size() - 3]) == 'd') ? 2 : 1;

Storage/Disk/DiskImage/Formats/SSD.hpp

@@ -22,15 +22,11 @@ class SSD: public MFMSectorDump {
 		/*!
 			Construct an @c SSD containing content from the file with name @c file_name.
 
-			@throws ErrorCantOpen if this file can't be opened.
-			@throws ErrorNotSSD if the file doesn't appear to contain a .SSD format image.
+			@throws Storage::FileHolder::Error::CantOpen if this file can't be opened.
+			@throws Error::InvalidFormat if the file doesn't appear to contain a .SSD format image.
 		*/
 		SSD(const std::string &file_name);
 
-		enum {
-			ErrorNotSSD,
-		};
-
 		int get_head_position_count() override;
 		int get_head_count() override;
 

Storage/Disk/DiskImage/Formats/WOZ.cpp

@@ -19,12 +19,13 @@ WOZ::WOZ(const std::string &file_name) :
 		'W', 'O', 'Z', '1',
 		static_cast<char>(0xff), 0x0a, 0x0d, 0x0a
 	};
-	if(!file_.check_signature(signature, 8)) throw ErrorNotWOZ;
+	if(!file_.check_signature(signature, 8)) throw Error::InvalidFormat;
 
 	// TODO: check CRC32, instead of skipping it.
 	file_.seek(4, SEEK_CUR);
 
 	// Parse all chunks up front.
+	bool has_tmap = false;
 	while(true) {
 		const uint32_t chunk_id = file_.get32le();
 		const uint32_t chunk_size = file_.get32le();
@@ -48,6 +49,7 @@ WOZ::WOZ(const std::string &file_name) :
 
 			case CK("TMAP"): {
 				file_.read(track_map_, 160);
+				has_tmap = true;
 			} break;
 
 			case CK("TRKS"): {
@@ -63,6 +65,8 @@ WOZ::WOZ(const std::string &file_name) :
 
 		file_.seek(end_of_chunk, SEEK_SET);
 	}
+
+	if(tracks_offset_ == -1 || !has_tmap) throw Error::InvalidFormat;
 }
 
 int WOZ::get_head_position_count() {

Storage/Disk/DiskImage/Formats/WOZ.hpp

@@ -24,10 +24,6 @@ class WOZ: public DiskImage {
 	public:
 		WOZ(const std::string &file_name);
 
-		enum {
-			ErrorNotWOZ
-		};
-
 		int get_head_position_count() override;
 		int get_head_count() override;
 		std::shared_ptr<Track> get_track_at_position(Track::Address address) override;
@@ -37,7 +33,7 @@ class WOZ: public DiskImage {
 		bool is_read_only_ = false;
 		bool is_3_5_disk_ = false;
 		uint8_t track_map_[160];
-		long tracks_offset_ = 0;
+		long tracks_offset_ = -1;
 };
 
 }

Storage/FileHolder.cpp

@@ -38,7 +38,7 @@ FileHolder::FileHolder(const std::string &file_name, FileMode ideal_mode)
 		break;
 	}
 
-	if(!file_) throw ErrorCantOpen;
+	if(!file_) throw Error::CantOpen;
 }
 
 uint32_t FileHolder::get32le() {

Storage/FileHolder.hpp

@@ -20,8 +20,8 @@ namespace Storage {
 
 class FileHolder final {
 	public:
-		enum {
-			ErrorCantOpen = -1
+		enum class Error {
+			CantOpen = -1
 		};
 
 		enum class FileMode {