Started sketching out support for the G64 file format.

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

@@ -43,6 +43,7 @@
 		4B73C71D1D036C030074D992 /* Vic20Document.xib in Resources */ = {isa = PBXBuildFile; fileRef = 4B73C71B1D036C030074D992 /* Vic20Document.xib */; };
 		4B92EACA1B7C112B00246143 /* 6502TimingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */; };
 		4BAB62AD1D3272D200DF5BA0 /* Disk.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BAB62AB1D3272D200DF5BA0 /* Disk.cpp */; };
+		4BAB62B51D327F7E00DF5BA0 /* G64.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4BAB62B31D327F7E00DF5BA0 /* G64.cpp */; };
 		4BB298EE1B587D8400A49093 /* 6502_functional_test.bin in Resources */ = {isa = PBXBuildFile; fileRef = 4BB297E01B587D8300A49093 /* 6502_functional_test.bin */; };
 		4BB298EF1B587D8400A49093 /* AllSuiteA.bin in Resources */ = {isa = PBXBuildFile; fileRef = 4BB297E11B587D8300A49093 /* AllSuiteA.bin */; };
 		4BB298F11B587D8400A49093 /*  start in Resources */ = {isa = PBXBuildFile; fileRef = 4BB297E51B587D8300A49093 /*  start */; };
@@ -419,6 +420,8 @@
 		4BAB62AB1D3272D200DF5BA0 /* Disk.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Disk.cpp; sourceTree = "<group>"; };
 		4BAB62AC1D3272D200DF5BA0 /* Disk.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Disk.hpp; sourceTree = "<group>"; };
 		4BAB62AE1D32730D00DF5BA0 /* Storage.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Storage.hpp; sourceTree = "<group>"; };
+		4BAB62B31D327F7E00DF5BA0 /* G64.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = G64.cpp; sourceTree = "<group>"; };
+		4BAB62B41D327F7E00DF5BA0 /* G64.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = G64.hpp; sourceTree = "<group>"; };
 		4BB297E01B587D8300A49093 /* 6502_functional_test.bin */ = {isa = PBXFileReference; lastKnownFileType = archive.macbinary; path = 6502_functional_test.bin; sourceTree = "<group>"; };
 		4BB297E11B587D8300A49093 /* AllSuiteA.bin */ = {isa = PBXFileReference; lastKnownFileType = archive.macbinary; path = AllSuiteA.bin; sourceTree = "<group>"; };
 		4BB297E51B587D8300A49093 /*  start */ = {isa = PBXFileReference; lastKnownFileType = file; path = " start"; sourceTree = "<group>"; };
@@ -978,12 +981,22 @@
 		4BAB62AA1D3272D200DF5BA0 /* Disk */ = {
 			isa = PBXGroup;
 			children = (
+				4BAB62B21D327F7E00DF5BA0 /* Formats */,
 				4BAB62AB1D3272D200DF5BA0 /* Disk.cpp */,
 				4BAB62AC1D3272D200DF5BA0 /* Disk.hpp */,
 			);
 			path = Disk;
 			sourceTree = "<group>";
 		};
+		4BAB62B21D327F7E00DF5BA0 /* Formats */ = {
+			isa = PBXGroup;
+			children = (
+				4BAB62B31D327F7E00DF5BA0 /* G64.cpp */,
+				4BAB62B41D327F7E00DF5BA0 /* G64.hpp */,
+			);
+			path = Formats;
+			sourceTree = "<group>";
+		};
 		4BB297E41B587D8300A49093 /* Wolfgang Lorenz 6502 test suite */ = {
 			isa = PBXGroup;
 			children = (
@@ -1850,6 +1863,7 @@
 				4B2A53A11D117D36003C6002 /* CSAtari2600.mm in Sources */,
 				4B69FB441C4D941400B5F0AA /* TapeUEF.cpp in Sources */,
 				4B4DC8211D2C2425003C5BF8 /* Vic20.cpp in Sources */,
+				4BAB62B51D327F7E00DF5BA0 /* G64.cpp in Sources */,
 				4BBF99141C8FBA6F0075DAFB /* CRTInputBufferBuilder.cpp in Sources */,
 				4B2409551C45AB05004DA684 /* Speaker.cpp in Sources */,
 				4B4DC8281D2C2470003C5BF8 /* C1540.cpp in Sources */,

Storage/Disk/Formats/G64.cpp

@@ -0,0 +1,91 @@
+//
+//  G64.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/07/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+#include "G64.hpp"
+
+using namespace Storage;
+
+G64::G64(const char *file_name)
+{
+	_file = fopen(file_name, "rb");
+
+	if(!_file)
+		throw ErrorNotGCR;
+
+	// read and check the file signature
+	char signature[8];
+	if(fread(signature, 1, 8, _file) != 12)
+		throw ErrorNotGCR;
+
+	if(memcmp(signature, "GCR-1541", 8))
+		throw ErrorNotGCR;
+
+	// check the version number
+	int version = fgetc(_file);
+	if(version != 0)
+	{
+		throw ErrorUnknownVersion;
+	}
+
+	// get the number of tracks and track size
+	_number_of_tracks = (uint8_t)fgetc(_file);
+	_maximum_track_size = (uint16_t)fgetc(_file);
+	_maximum_track_size |= (uint16_t)fgetc(_file) << 8;
+}
+
+G64::~G64()
+{
+	if(_file) fclose(_file);
+}
+
+unsigned int G64::get_head_position_count()
+{
+	// give at least 84 tracks, to yield the normal geometry but,
+	// if there are more, shove them in
+	return _number_of_tracks > 84 ? _number_of_tracks : 84;
+}
+
+std::shared_ptr<Track> G64::get_track_at_position(unsigned int position)
+{
+	std::shared_ptr<Track> resulting_track;
+
+	// if there's definitely no track here, return the empty track
+	// (TODO: should be supplying one with an index hole?)
+	if(position >= _number_of_tracks) return resulting_track;
+
+	// seek to this track's entry in the track table
+	fseek(_file, SEEK_SET, (int)((position * 4) + 0xc));
+
+	// read the track offset
+	uint32_t track_offset;
+	track_offset = (uint32_t)fgetc(_file);
+	track_offset |= (uint32_t)fgetc(_file) << 8;
+	track_offset |= (uint32_t)fgetc(_file) << 16;
+	track_offset |= (uint32_t)fgetc(_file) << 24;
+
+	// if the track offset is zero, this track doesn't exist, so...
+	if(!track_offset) return resulting_track;
+
+	// seek to the track start
+	fseek(_file, SEEK_SET, (int)track_offset);
+
+	// get the real track length
+	uint16_t track_length;
+	track_length = (uint16_t)fgetc(_file);
+	track_length |= (uint16_t)fgetc(_file) << 8;
+
+	// grab the byte contents of this track
+	uint8_t track_contents[track_length];
+	fread(track_contents, 1, track_length, _file);
+
+	// check for speed-zone contents
+
+	// TODO: package track_contents and speed_zones into a PCM track
+
+	return resulting_track;
+}

Storage/Disk/Formats/G64.hpp

@@ -0,0 +1,41 @@
+//
+//  G64.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/07/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+#ifndef G64_hpp
+#define G64_hpp
+
+#include "../Disk.hpp"
+
+namespace Storage {
+
+class PCMTrack: public Track {
+};
+
+class G64: public Disk {
+	public:
+		G64(const char *file_name);
+		~G64();
+
+		enum {
+			ErrorNotGCR,
+			ErrorUnknownVersion
+		};
+
+		unsigned int get_head_position_count();
+		std::shared_ptr<Track> get_track_at_position(unsigned int position);
+
+	private:
+		FILE *_file;
+
+		uint8_t _number_of_tracks;
+		uint16_t _maximum_track_size;
+};
+
+};
+
+#endif /* G64_hpp */