Merge pull request #955 from TomHarte/FAT12

Adds a FAT12 parser.

Analyser/Static/Enterprise/StaticAnalyser.cpp

@@ -9,13 +9,29 @@
 #include "StaticAnalyser.hpp"
 #include "Target.hpp"
 
+#include "../../../Storage/Disk/Parsers/FAT.hpp"
+
+#include <algorithm>
+
+namespace {
+
+bool insensitive_equal(const std::string &lhs, const std::string &rhs) {
+	return std::equal(
+		lhs.begin(), lhs.end(),
+		rhs.begin(), rhs.end(),
+		[] (char l, char r) {
+			return tolower(l) == tolower(r);
+	});
+}
+
+}
+
 Analyser::Static::TargetList Analyser::Static::Enterprise::GetTargets(const Media &media, const std::string &, TargetPlatform::IntType) {
 	// This analyser can comprehend disks only.
 	if(media.disks.empty()) return {};
 
-	// Otherwise, for now: wave it through.
+	// Otherwise, assume a return will happen.
 	Analyser::Static::TargetList targets;
-
 	using Target = Analyser::Static::Enterprise::Target;
 	auto *const target = new Target;
 	target->media = media;
@@ -23,9 +39,40 @@ Analyser::Static::TargetList Analyser::Static::Enterprise::GetTargets(const Medi
 	// Always require a BASIC.
 	target->basic_version = Target::BASICVersion::Any;
 
-	// If this is a single-sided floppy disk, guess the Macintosh 512kb.
+	// Inspect any supplied disks.
 	if(!media.disks.empty()) {
+		// DOS will be needed.
 		target->dos = Target::DOS::EXDOS;
+
+		// Grab the volume information, which includes the root directory.
+		auto volume = Storage::Disk::FAT::GetVolume(media.disks.front());
+		if(volume) {
+			// If there's an EXDOS.INI then this disk should be able to boot itself.
+			// If not but if there's only one .COM or .BAS, automatically load that.
+			// Failing that, issue a :DIR and give the user a clue as to how to load.
+			const Storage::Disk::FAT::File *selected_file = nullptr;
+			bool has_exdos_ini = false;
+			bool did_pick_file = false;
+			for(const auto &file: (*volume).root_directory) {
+				if(insensitive_equal(file.name, "exdos") && insensitive_equal(file.extension, "ini")) {
+					has_exdos_ini = true;
+					break;
+				}
+
+				if(insensitive_equal(file.extension, "com") || insensitive_equal(file.extension, "bas")) {
+					did_pick_file = !selected_file;
+					selected_file = &file;
+				}
+			}
+
+			if(!has_exdos_ini) {
+				if(did_pick_file) {
+					target->loading_command = std::string("run \"") + selected_file->name + "." + selected_file->extension + "\"";
+				} else {
+					target->loading_command = ":dir\n";
+				}
+			}
+		}
 	}
 
 	targets.push_back(std::unique_ptr<Analyser::Static::Target>(target));

Machines/Enterprise/Enterprise.cpp

@@ -220,6 +220,12 @@ template <bool has_disk_controller> class ConcreteMachine:
 			if(!target.loading_command.empty()) {
 				type_string(target.loading_command);
 			}
+
+			// Ensure the splash screen is automatically skipped if any media has been provided.
+			if(!target.media.empty()) {
+				should_skip_splash_screen_ = !target.media.empty();
+				typer_delay_ = 2;
+			}
 		}
 
 		~ConcreteMachine() {
@@ -438,18 +444,18 @@ template <bool has_disk_controller> class ConcreteMachine:
 							// spot that a scan of the keyboard just finished. Which makes it
 							// time to enqueue the next keypress.
 							//
-							// Re: is_past_splash_screen_ and typer_delay_, assume that a
+							// Re: should_skip_splash_screen_ and typer_delay_, assume that a
 							// single keypress is necessary to get past the Enterprise splash
 							// screen, then a pause in keypressing while BASIC or whatever
 							// starts up, then presses can resume.
-							if(typer_ && active_key_line_ == 9 && !(*cycle.value & 0xf)) {
-								if(!is_past_splash_screen_) {
+							if(active_key_line_ == 9 && !(*cycle.value & 0xf) && (should_skip_splash_screen_ || typer_)) {
+								if(should_skip_splash_screen_) {
 									set_key_state(uint16_t(Key::Space), typer_delay_);
 									if(typer_delay_) {
 										--typer_delay_;
 									} else {
 										typer_delay_ = 60;
-										is_past_splash_screen_ = true;
+										should_skip_splash_screen_ = false;
 									}
 								} else {
 									if(!typer_delay_) {
@@ -620,15 +626,20 @@ template <bool has_disk_controller> class ConcreteMachine:
 		void type_string(const std::string &string) final {
 			Utility::TypeRecipient<CharacterMapper>::add_typer(string);
 
-			is_past_splash_screen_ = !z80_.get_is_resetting();
-			typer_delay_ = !is_past_splash_screen_;
+			if(z80_.get_is_resetting()) {
+				should_skip_splash_screen_ = true;
+				typer_delay_ = 1;
+			} else {
+				should_skip_splash_screen_ = false;
+				typer_delay_ = 0;
+			}
 		}
 
 		bool can_type(char c) const final {
 			return Utility::TypeRecipient<CharacterMapper>::can_type(c);
 		}
 
-		bool is_past_splash_screen_ = false;
+		bool should_skip_splash_screen_ = false;
 		int typer_delay_ = 30;
 
 		// MARK: - MediaTarget

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

@@ -241,6 +241,7 @@
 		4B4518A31F75FD1C00926311 /* HFE.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4518951F75FD1B00926311 /* HFE.cpp */; };
 		4B4518A41F75FD1C00926311 /* OricMFMDSK.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4518971F75FD1B00926311 /* OricMFMDSK.cpp */; };
 		4B4518A51F75FD1C00926311 /* SSD.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4518991F75FD1B00926311 /* SSD.cpp */; };
+		4B47770B268FBE4D005C2340 /* FAT.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B477709268FBE4D005C2340 /* FAT.cpp */; };
 		4B47F6C5241C87A100ED06F7 /* Struct.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B47F6C4241C87A100ED06F7 /* Struct.cpp */; };
 		4B47F6C6241C87A100ED06F7 /* Struct.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B47F6C4241C87A100ED06F7 /* Struct.cpp */; };
 		4B49F0A923346F7A0045E6A6 /* MacintoshOptions.xib in Resources */ = {isa = PBXBuildFile; fileRef = 4B49F0A723346F7A0045E6A6 /* MacintoshOptions.xib */; };
@@ -1276,6 +1277,8 @@
 		4B45189A1F75FD1B00926311 /* SSD.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = SSD.hpp; sourceTree = "<group>"; };
 		4B4518A71F76004200926311 /* TapeParser.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = TapeParser.hpp; path = Parsers/TapeParser.hpp; sourceTree = "<group>"; };
 		4B4518A81F76022000926311 /* DiskImageImplementation.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = DiskImageImplementation.hpp; sourceTree = "<group>"; };
+		4B477709268FBE4D005C2340 /* FAT.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = FAT.cpp; path = Parsers/FAT.cpp; sourceTree = "<group>"; };
+		4B47770A268FBE4D005C2340 /* FAT.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; name = FAT.hpp; path = Parsers/FAT.hpp; sourceTree = "<group>"; };
 		4B47F6C4241C87A100ED06F7 /* Struct.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Struct.cpp; sourceTree = "<group>"; };
 		4B49F0A823346F7A0045E6A6 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.xib; name = Base; path = "Clock Signal/Base.lproj/MacintoshOptions.xib"; sourceTree = SOURCE_ROOT; };
 		4B4A762E1DB1A3FA007AAE2E /* AY38910.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = AY38910.cpp; sourceTree = "<group>"; };
@@ -2657,7 +2660,9 @@
 			isa = PBXGroup;
 			children = (
 				4B3FE75C1F3CF68B00448EE4 /* CPM.cpp */,
+				4B477709268FBE4D005C2340 /* FAT.cpp */,
 				4B3FE75D1F3CF68B00448EE4 /* CPM.hpp */,
+				4B47770A268FBE4D005C2340 /* FAT.hpp */,
 			);
 			name = Parsers;
 			sourceTree = "<group>";
@@ -5579,6 +5584,7 @@
 				4B69FB3D1C4D908A00B5F0AA /* Tape.cpp in Sources */,
 				4B4518841F75E91A00926311 /* UnformattedTrack.cpp in Sources */,
 				4B65086022F4CF8D009C1100 /* Keyboard.cpp in Sources */,
+				4B47770B268FBE4D005C2340 /* FAT.cpp in Sources */,
 				4B894528201967B4007DE474 /* Disk.cpp in Sources */,
 				4B2E86CF25D8D8C70024F1E9 /* Keyboard.cpp in Sources */,
 				4BBB70A4202011C2002FE009 /* MultiMediaTarget.cpp in Sources */,

Storage/Disk/Parsers/FAT.cpp

@@ -0,0 +1,179 @@
+//
+//  FAT.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 02/07/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#include "FAT.hpp"
+
+#include "../Encodings/MFM/Parser.hpp"
+
+#include <iostream>
+
+using namespace Storage::Disk;
+
+FAT::Volume::CHS FAT::Volume::chs_for_sector(int sector) const {
+	const auto track = sector / sectors_per_track;
+
+	// Sides are interleaved.
+	return CHS{
+		track / head_count,
+		track % head_count,
+		1 + (sector % sectors_per_track)
+	 };
+}
+
+int FAT::Volume::sector_for_cluster(uint16_t cluster) const {
+	// The first cluster in the data area is numbered as 2.
+	return ((cluster - 2) * sectors_per_cluster) + first_data_sector;
+}
+
+namespace {
+
+template <typename CharT> std::string trim(CharT start, CharT end) {
+	std::string result(start, end);
+	result.erase(std::find_if(result.rbegin(), result.rend(), [](unsigned char ch) {
+		return !std::isspace(ch);
+	}).base(), result.end());
+	return result;
+}
+
+FAT::Directory directory_from(const std::vector<uint8_t> &contents) {
+	FAT::Directory result;
+
+	// Worst case: parse until the amount of data supplied is fully consumed.
+	for(size_t base = 0; base < contents.size(); base += 32) {
+		// An entry starting with byte 0 indicates end-of-directory.
+		if(!contents[base]) {
+			break;
+		}
+
+		// An entry starting in 0xe5 is merely deleted.
+		if(contents[base] == 0xe5) {
+			continue;
+		}
+
+		// Otherwise create and populate a new entry.
+		result.emplace_back();
+		result.back().name = trim(&contents[base], &contents[base+8]);
+		result.back().extension = trim(&contents[base+8], &contents[base+11]);
+		result.back().attributes = contents[base + 11];
+		result.back().time = uint16_t(contents[base+22] | (contents[base+23] << 8));
+		result.back().date = uint16_t(contents[base+24] | (contents[base+25] << 8));
+		result.back().starting_cluster = uint16_t(contents[base+26] | (contents[base+27] << 8));
+		result.back().size = uint32_t(
+			contents[base+28] |
+			(contents[base+29] << 8) |
+			(contents[base+30] << 16) |
+			(contents[base+31] << 24)
+		);
+	}
+
+	return result;
+}
+
+}
+
+std::optional<FAT::Volume> FAT::GetVolume(const std::shared_ptr<Storage::Disk::Disk> &disk) {
+	Storage::Encodings::MFM::Parser parser(true, disk);
+
+	// Grab the boot sector; that'll be enough to establish the volume.
+	Storage::Encodings::MFM::Sector *const boot_sector = parser.get_sector(0, 0, 1);
+	if(!boot_sector || boot_sector->samples.empty() || boot_sector->samples[0].size() < 512) {
+		return std::nullopt;
+	}
+
+	// Obtain volume details.
+	const auto &data = boot_sector->samples[0];
+	FAT::Volume volume;
+	volume.bytes_per_sector = uint16_t(data[11] | (data[12] << 8));
+	volume.sectors_per_cluster = data[13];
+	volume.reserved_sectors = uint16_t(data[14] | (data[15] << 8));
+	volume.fat_copies = data[16];
+	const uint16_t root_directory_entries = uint16_t(data[17] | (data[18] << 8));
+	volume.total_sectors = uint16_t(data[19] | (data[20] << 8));
+	volume.sectors_per_fat = uint16_t(data[22] | (data[23] << 8));
+	volume.sectors_per_track = uint16_t(data[24] | (data[25] << 8));
+	volume.head_count = uint16_t(data[26] | (data[27] << 8));
+	volume.correct_signature = data[510] == 0x55 && data[511] == 0xaa;
+
+	const size_t root_directory_sectors = (root_directory_entries*32 + volume.bytes_per_sector - 1) / volume.bytes_per_sector;
+	volume.first_data_sector = int(volume.reserved_sectors + volume.sectors_per_fat*volume.fat_copies + root_directory_sectors);
+
+	// Grab the FAT.
+	std::vector<uint8_t> source_fat;
+	for(int c = 0; c < volume.sectors_per_fat; c++) {
+		const int sector_number = volume.reserved_sectors + c;
+		const auto address = volume.chs_for_sector(sector_number);
+
+		Storage::Encodings::MFM::Sector *const fat_sector =
+			parser.get_sector(address.head, address.cylinder, uint8_t(address.sector));
+		if(!fat_sector || fat_sector->samples.empty() || fat_sector->samples[0].size() != volume.bytes_per_sector) {
+			return std::nullopt;
+		}
+		std::copy(fat_sector->samples[0].begin(), fat_sector->samples[0].end(), std::back_inserter(source_fat));
+	}
+
+	// Decode the FAT.
+	// TODO: stop assuming FAT12 here.
+	for(size_t c = 0; c < source_fat.size(); c += 3) {
+		const uint32_t double_cluster = uint32_t(source_fat[c] + (source_fat[c + 1] << 8) + (source_fat[c + 2] << 16));
+		volume.fat.push_back(uint16_t(double_cluster & 0xfff));
+		volume.fat.push_back(uint16_t(double_cluster >> 12));
+	}
+
+	// Grab the root directory.
+	std::vector<uint8_t> root_directory;
+	for(size_t c = 0; c < root_directory_sectors; c++) {
+		const auto sector_number = int(volume.reserved_sectors + c + volume.sectors_per_fat*volume.fat_copies);
+		const auto address = volume.chs_for_sector(sector_number);
+
+		Storage::Encodings::MFM::Sector *const sector =
+			parser.get_sector(address.head, address.cylinder, uint8_t(address.sector));
+		if(!sector || sector->samples.empty() || sector->samples[0].size() != volume.bytes_per_sector) {
+			return std::nullopt;
+		}
+		std::copy(sector->samples[0].begin(), sector->samples[0].end(), std::back_inserter(root_directory));
+	}
+	volume.root_directory = directory_from(root_directory);
+
+	return volume;
+}
+
+std::optional<std::vector<uint8_t>> FAT::GetFile(const std::shared_ptr<Storage::Disk::Disk> &disk, const Volume &volume, const File &file) {
+	Storage::Encodings::MFM::Parser parser(true, disk);
+
+	std::vector<uint8_t> contents;
+
+	// In FAT cluster numbers describe a linked list via the FAT table, with values above $FF0 being reserved
+	// (relevantly: FF7 means bad cluster; FF8–FFF mean end-of-file).
+	uint16_t cluster = file.starting_cluster;
+	do {
+		const int sector = volume.sector_for_cluster(cluster);
+
+		for(int c = 0; c < volume.sectors_per_cluster; c++) {
+			const auto address = volume.chs_for_sector(sector + c);
+
+			Storage::Encodings::MFM::Sector *const sector_contents =
+				parser.get_sector(address.head, address.cylinder, uint8_t(address.sector));
+			if(!sector_contents || sector_contents->samples.empty() || sector_contents->samples[0].size() != volume.bytes_per_sector) {
+				return std::nullopt;
+			}
+			std::copy(sector_contents->samples[0].begin(), sector_contents->samples[0].end(), std::back_inserter(contents));
+		}
+
+		cluster = volume.fat[cluster];
+	} while(cluster < 0xff0);
+
+	return contents;
+}
+
+std::optional<FAT::Directory> FAT::GetDirectory(const std::shared_ptr<Storage::Disk::Disk> &disk, const Volume &volume, const File &file) {
+	const auto contents = GetFile(disk, volume, file);
+	if(!contents) {
+		return std::nullopt;
+	}
+	return directory_from(*contents);
+}

Storage/Disk/Parsers/FAT.hpp

@@ -0,0 +1,79 @@
+//
+//  FAT.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 02/07/2021.
+//  Copyright © 2021 Thomas Harte. All rights reserved.
+//
+
+#ifndef Storage_Disk_Parsers_FAT_hpp
+#define Storage_Disk_Parsers_FAT_hpp
+
+#include "../Disk.hpp"
+
+#include <cstdint>
+#include <optional>
+#include <string>
+#include <vector>
+
+namespace Storage {
+namespace Disk {
+namespace FAT {
+
+struct File {
+	std::string name;
+	std::string extension;
+	uint8_t attributes = 0;
+	uint16_t time = 0;	// TODO: offer time/date decoders.
+	uint16_t date = 0;
+	uint16_t starting_cluster = 0;
+	uint32_t size = 0;
+
+	enum Attribute: uint8_t {
+		ReadOnly	= (1 << 0),
+		Hidden		= (1 << 1),
+		System		= (1 << 2),
+		VolumeLabel	= (1 << 3),
+		Directory	= (1 << 4),
+		Archive		= (1 << 5),
+	};
+};
+
+using Directory = std::vector<File>;
+
+struct Volume {
+	uint16_t bytes_per_sector = 0;
+	uint8_t sectors_per_cluster = 0;
+	uint16_t reserved_sectors = 0;
+	uint8_t fat_copies = 0;
+	uint16_t total_sectors = 0;
+	uint16_t sectors_per_fat = 0;
+	uint16_t sectors_per_track = 0;
+	uint16_t head_count = 0;
+	uint16_t hidden_sectors = 0;
+	bool correct_signature = false;
+	int first_data_sector = 0;
+
+	std::vector<uint16_t> fat;
+	Directory root_directory;
+
+	struct CHS {
+		int cylinder;
+		int head;
+		int sector;
+	};
+	/// @returns a direct sector -> CHS address translation.
+	CHS chs_for_sector(int sector) const;
+	/// @returns the CHS address for the numbered cluster within the data area.
+	int sector_for_cluster(uint16_t cluster) const;
+};
+
+std::optional<Volume> GetVolume(const std::shared_ptr<Storage::Disk::Disk> &disk);
+std::optional<std::vector<uint8_t>> GetFile(const std::shared_ptr<Storage::Disk::Disk> &disk, const Volume &volume, const File &file);
+std::optional<Directory> GetDirectory(const std::shared_ptr<Storage::Disk::Disk> &disk, const Volume &volume, const File &file);
+
+}
+}
+}
+
+#endif /* FAT_hpp */