Aaru/DiscImageChef.DiscImages/TeleDisk.cs

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : TeleDisk.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages Sydex TeleDisk disk images.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2018 Natalia Portillo
// For Advanced Compression support (aka LZH):
// Copyright © 2017 Miodrag Milanovic
// Copyright © 1988 Haruhiko OKUMURA
// Copyright © 1988 Haruyasu YOSHIZAKI
// Copyright © 1988 Kenji RIKITAKE
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;

namespace DiscImageChef.DiscImages
{
    // Created following notes from Dave Dunfield
    // http://www.classiccmp.org/dunfield/img54306/td0notes.txt
    public class TeleDisk : ImagePlugin
    {
        // "TD" as little endian uint.
        const ushort TD_MAGIC = 0x4454;
        // "td" as little endian uint. Means whole file is compressed (aka Advanced Compression)
        const ushort TD_ADV_COMP_MAGIC = 0x6474;

        // DataRates
        const byte DATA_RATE_250KBPS = 0x00;
        const byte DATA_RATE_300KBPS = 0x01;
        const byte DATA_RATE_500KBPS = 0x02;

        // TeleDisk drive types
        const byte DRIVE_TYPE_525_HD_DD_DISK = 0x00;
        const byte DRIVE_TYPE_525_HD = 0x01;
        const byte DRIVE_TYPE_525_DD = 0x02;
        const byte DRIVE_TYPE_35_DD = 0x03;
        const byte DRIVE_TYPE_35_HD = 0x04;
        const byte DRIVE_TYPE_8_INCH = 0x05;
        const byte DRIVE_TYPE_35_ED = 0x06;

        // Stepping
        const byte STEPPING_SINGLE = 0x00;
        const byte STEPPING_DOUBLE = 0x01;
        const byte STEPPING_EVEN_ONLY = 0x02;
        // If this bit is set, there is a comment block
        const byte COMMENT_BLOCK_PRESENT = 0x80;

        // CRC polynomial
        const ushort TELE_DISK_CRC_POLY = 0xA097;

        // Sector sizes table
        const byte SECTOR_SIZE_128 = 0x00;
        const byte SECTOR_SIZE_256 = 0x01;
        const byte SECTOR_SIZE_512 = 0x02;
        const byte SECTOR_SIZE_1K = 0x03;
        const byte SECTOR_SIZE_2K = 0x04;
        const byte SECTOR_SIZE_4K = 0x05;
        const byte SECTOR_SIZE_8K = 0x06;

        // Flags
        // Address mark repeats inside same track
        const byte FLAGS_SECTOR_DUPLICATE = 0x01;
        // Sector gave CRC error on reading
        const byte FLAGS_SECTOR_CRC_ERROR = 0x02;
        // Address mark indicates deleted sector
        const byte FLAGS_SECTOR_DELETED = 0x04;
        // Sector skipped as FAT said it's unused
        const byte FLAGS_SECTOR_SKIPPED = 0x10;
        // There was an address mark, but no data following
        const byte FLAGS_SECTOR_DATALESS = 0x20;
        // There was data without address mark
        const byte FLAGS_SECTOR_NO_ID = 0x40;

        // Data block encodings
        // Data is copied as is
        const byte DATA_BLOCK_COPY = 0x00;
        // Data is encoded as a pair of len.value uint16s
        const byte DATA_BLOCK_PATTERN = 0x01;
        // Data is encoded as RLE
        const byte DATA_BLOCK_RLE = 0x02;
        bool aDiskCrcHasFailed;
        byte[] commentBlock;
        TeleDiskCommentBlockHeader commentHeader;

        TeleDiskHeader header;
        Stream inStream;
        byte[] leadOut;
        // Cylinder by head, sector data matrix
        byte[][][][] sectorsData;
        List<ulong> sectorsWhereCrcHasFailed;
        // LBA, data
        uint totalDiskSize;

        public TeleDisk()
        {
            Name = "Sydex TeleDisk";
            PluginUuid = new Guid("0240B7B1-E959-4CDC-B0BD-386D6E467B88");
            ImageInfo = new ImageInfo
            {
                ReadableSectorTags = new List<SectorTagType>(),
                ReadableMediaTags = new List<MediaTagType>(),
                ImageHasPartitions = false,
                ImageHasSessions = false,
                ImageApplication = "Sydex TeleDisk",
                ImageComments = null,
                ImageCreator = null,
                MediaManufacturer = null,
                MediaModel = null,
                MediaSerialNumber = null,
                MediaBarcode = null,
                MediaPartNumber = null,
                MediaSequence = 0,
                LastMediaSequence = 0,
                DriveManufacturer = null,
                DriveModel = null,
                DriveSerialNumber = null,
                DriveFirmwareRevision = null
            };
            aDiskCrcHasFailed = false;
            sectorsWhereCrcHasFailed = new List<ulong>();
        }

        public override bool IdentifyImage(Filter imageFilter)
        {
            header = new TeleDiskHeader();
            byte[] headerBytes = new byte[12];
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);

            stream.Read(headerBytes, 0, 12);

            header.Signature = BitConverter.ToUInt16(headerBytes, 0);

            if(header.Signature != TD_MAGIC && header.Signature != TD_ADV_COMP_MAGIC) return false;

            header.Sequence = headerBytes[2];
            header.DiskSet = headerBytes[3];
            header.Version = headerBytes[4];
            header.DataRate = headerBytes[5];
            header.DriveType = headerBytes[6];
            header.Stepping = headerBytes[7];
            header.DosAllocation = headerBytes[8];
            header.Sides = headerBytes[9];
            header.Crc = BitConverter.ToUInt16(headerBytes, 10);

            byte[] headerBytesForCrc = new byte[10];
            Array.Copy(headerBytes, headerBytesForCrc, 10);
            ushort calculatedHeaderCrc = TeleDiskCrc(0x0000, headerBytesForCrc);

            DicConsole.DebugWriteLine("TeleDisk plugin", "header.signature = 0x{0:X4}", header.Signature);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.sequence = 0x{0:X2}", header.Sequence);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.diskSet = 0x{0:X2}", header.DiskSet);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.version = 0x{0:X2}", header.Version);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.dataRate = 0x{0:X2}", header.DataRate);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.driveType = 0x{0:X2}", header.DriveType);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.stepping = 0x{0:X2}", header.Stepping);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.dosAllocation = 0x{0:X2}", header.DosAllocation);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.sides = 0x{0:X2}", header.Sides);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.crc = 0x{0:X4}", header.Crc);
            DicConsole.DebugWriteLine("TeleDisk plugin", "calculated header crc = 0x{0:X4}", calculatedHeaderCrc);

            // We need more checks as the magic is too simply.
            // This may deny legal images

            // That would be much of a coincidence
            if(header.Crc == calculatedHeaderCrc) return true;

            if(header.Sequence != 0x00) return false;

            if(header.DataRate != DATA_RATE_250KBPS && header.DataRate != DATA_RATE_300KBPS &&
               header.DataRate != DATA_RATE_500KBPS) return false;

            return header.DriveType == DRIVE_TYPE_35_DD || header.DriveType == DRIVE_TYPE_35_ED ||
                   header.DriveType == DRIVE_TYPE_35_HD || header.DriveType == DRIVE_TYPE_525_DD ||
                   header.DriveType == DRIVE_TYPE_525_HD || header.DriveType == DRIVE_TYPE_525_HD_DD_DISK ||
                   header.DriveType == DRIVE_TYPE_8_INCH;
        }

        public override bool OpenImage(Filter imageFilter)
        {
            header = new TeleDiskHeader();
            byte[] headerBytes = new byte[12];
            inStream = imageFilter.GetDataForkStream();
            MemoryStream stream = new MemoryStream();
            inStream.Seek(0, SeekOrigin.Begin);

            inStream.Read(headerBytes, 0, 12);
            stream.Write(headerBytes, 0, 12);

            header.Signature = BitConverter.ToUInt16(headerBytes, 0);

            if(header.Signature != TD_MAGIC && header.Signature != TD_ADV_COMP_MAGIC) return false;

            header.Sequence = headerBytes[2];
            header.DiskSet = headerBytes[3];
            header.Version = headerBytes[4];
            header.DataRate = headerBytes[5];
            header.DriveType = headerBytes[6];
            header.Stepping = headerBytes[7];
            header.DosAllocation = headerBytes[8];
            header.Sides = headerBytes[9];
            header.Crc = BitConverter.ToUInt16(headerBytes, 10);

            ImageInfo.ImageName = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
            ImageInfo.ImageVersion = $"{(header.Version & 0xF0) >> 4}.{header.Version & 0x0F}";
            ImageInfo.ImageApplication = ImageInfo.ImageVersion;

            byte[] headerBytesForCrc = new byte[10];
            Array.Copy(headerBytes, headerBytesForCrc, 10);
            ushort calculatedHeaderCrc = TeleDiskCrc(0x0000, headerBytesForCrc);

            DicConsole.DebugWriteLine("TeleDisk plugin", "header.signature = 0x{0:X4}", header.Signature);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.sequence = 0x{0:X2}", header.Sequence);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.diskSet = 0x{0:X2}", header.DiskSet);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.version = 0x{0:X2}", header.Version);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.dataRate = 0x{0:X2}", header.DataRate);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.driveType = 0x{0:X2}", header.DriveType);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.stepping = 0x{0:X2}", header.Stepping);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.dosAllocation = 0x{0:X2}", header.DosAllocation);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.sides = 0x{0:X2}", header.Sides);
            DicConsole.DebugWriteLine("TeleDisk plugin", "header.crc = 0x{0:X4}", header.Crc);
            DicConsole.DebugWriteLine("TeleDisk plugin", "calculated header crc = 0x{0:X4}", calculatedHeaderCrc);

            // We need more checks as the magic is too simply.
            // This may deny legal images

            // That would be much of a coincidence
            if(header.Crc != calculatedHeaderCrc)
            {
                aDiskCrcHasFailed = true;
                DicConsole.DebugWriteLine("TeleDisk plugin", "Calculated CRC does not coincide with stored one.");
            }

            if(header.Sequence != 0x00) return false;

            if(header.DataRate != DATA_RATE_250KBPS && header.DataRate != DATA_RATE_300KBPS &&
               header.DataRate != DATA_RATE_500KBPS) return false;

            if(header.DriveType != DRIVE_TYPE_35_DD && header.DriveType != DRIVE_TYPE_35_ED &&
               header.DriveType != DRIVE_TYPE_35_HD && header.DriveType != DRIVE_TYPE_525_DD &&
               header.DriveType != DRIVE_TYPE_525_HD && header.DriveType != DRIVE_TYPE_525_HD_DD_DISK &&
               header.DriveType != DRIVE_TYPE_8_INCH) return false;

            if(header.Signature == TD_ADV_COMP_MAGIC)
            {
                int rd;
                inStream.Seek(12, SeekOrigin.Begin);
                stream.Seek(12, SeekOrigin.Begin);
                init_Decode();
                do if((rd = Decode(out byte[] obuf, BUFSZ)) > 0) stream.Write(obuf, 0, rd);
                while(rd == BUFSZ);
            }
            else
            {
                // Not using Stream.CopyTo() because it's failing with LZIP
                byte[] copybuf = new byte[inStream.Length];
                inStream.Seek(0, SeekOrigin.Begin);
                inStream.Read(copybuf, 0, copybuf.Length);
                stream.Seek(0, SeekOrigin.Begin);
                stream.Write(copybuf, 0, copybuf.Length);
            }

            stream.Seek(12, SeekOrigin.Begin);

            ImageInfo.ImageCreationTime = DateTime.MinValue;

            if((header.Stepping & COMMENT_BLOCK_PRESENT) == COMMENT_BLOCK_PRESENT)
            {
                commentHeader = new TeleDiskCommentBlockHeader();

                byte[] commentHeaderBytes = new byte[10];

                stream.Read(commentHeaderBytes, 0, 10);
                commentHeader.Crc = BitConverter.ToUInt16(commentHeaderBytes, 0);
                commentHeader.Length = BitConverter.ToUInt16(commentHeaderBytes, 2);
                commentHeader.Year = commentHeaderBytes[4];
                commentHeader.Month = commentHeaderBytes[5];
                commentHeader.Day = commentHeaderBytes[6];
                commentHeader.Hour = commentHeaderBytes[7];
                commentHeader.Minute = commentHeaderBytes[8];
                commentHeader.Second = commentHeaderBytes[9];

                commentBlock = new byte[commentHeader.Length];
                stream.Read(commentBlock, 0, commentHeader.Length);

                byte[] commentBlockForCrc = new byte[commentHeader.Length + 8];
                Array.Copy(commentHeaderBytes, 2, commentBlockForCrc, 0, 8);
                Array.Copy(commentBlock, 0, commentBlockForCrc, 8, commentHeader.Length);

                ushort cmtcrc = TeleDiskCrc(0, commentBlockForCrc);

                DicConsole.DebugWriteLine("TeleDisk plugin", "Comment header");
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.crc = 0x{0:X4}", commentHeader.Crc);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tCalculated CRC = 0x{0:X4}", cmtcrc);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.length = {0} bytes",
                                          commentHeader.Length);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.year = {0}", commentHeader.Year);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.month = {0}", commentHeader.Month);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.day = {0}", commentHeader.Day);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.hour = {0}", commentHeader.Hour);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.minute = {0}", commentHeader.Minute);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tcommentheader.second = {0}", commentHeader.Second);

                aDiskCrcHasFailed |= cmtcrc != commentHeader.Crc;

                for(int i = 0; i < commentBlock.Length; i++)
                    // Replace NULLs, used by TeleDisk as newline markers, with UNIX newline marker
                    if(commentBlock[i] == 0x00) commentBlock[i] = 0x0A;

                ImageInfo.ImageComments = Encoding.ASCII.GetString(commentBlock);

                DicConsole.DebugWriteLine("TeleDisk plugin", "Comment");
                DicConsole.DebugWriteLine("TeleDisk plugin", "{0}", ImageInfo.ImageComments);

                ImageInfo.ImageCreationTime = new DateTime(commentHeader.Year + 1900, commentHeader.Month + 1,
                                                           commentHeader.Day, commentHeader.Hour, commentHeader.Minute,
                                                           commentHeader.Second, DateTimeKind.Unspecified);
            }

            if(ImageInfo.ImageCreationTime == DateTime.MinValue)
                ImageInfo.ImageCreationTime = imageFilter.GetCreationTime();
            ImageInfo.ImageLastModificationTime = imageFilter.GetLastWriteTime();

            DicConsole.DebugWriteLine("TeleDisk plugin", "Image created on {0}", ImageInfo.ImageCreationTime);
            DicConsole.DebugWriteLine("TeleDisk plugin", "Image modified on {0}", ImageInfo.ImageLastModificationTime);

            DicConsole.DebugWriteLine("TeleDisk plugin", "Parsing image");

            totalDiskSize = 0;
            ImageInfo.ImageSize = 0;

            int totalCylinders = -1;
            int totalHeads = -1;
            int maxSector = -1;
            int totalSectors = 0;
            long currentPos = stream.Position;
            ImageInfo.SectorSize = uint.MaxValue;
            ImageInfo.SectorsPerTrack = uint.MaxValue;

            // Count cylinders
            while(true)
            {
                TeleDiskTrackHeader teleDiskTrack = new TeleDiskTrackHeader
                {
                    Sectors = (byte)stream.ReadByte(),
                    Cylinder = (byte)stream.ReadByte(),
                    Head = (byte)stream.ReadByte(),
                    Crc = (byte)stream.ReadByte()
                };

                if(teleDiskTrack.Cylinder > totalCylinders) totalCylinders = teleDiskTrack.Cylinder;
                if(teleDiskTrack.Head > totalHeads) totalHeads = teleDiskTrack.Head;

                if(teleDiskTrack.Sectors == 0xFF) // End of disk image
                    break;

                for(byte processedSectors = 0; processedSectors < teleDiskTrack.Sectors; processedSectors++)
                {
                    TeleDiskSectorHeader teleDiskSector = new TeleDiskSectorHeader();
                    TeleDiskDataHeader teleDiskData = new TeleDiskDataHeader();
                    byte[] dataSizeBytes = new byte[2];

                    teleDiskSector.Cylinder = (byte)stream.ReadByte();
                    teleDiskSector.Head = (byte)stream.ReadByte();
                    teleDiskSector.SectorNumber = (byte)stream.ReadByte();
                    teleDiskSector.SectorSize = (byte)stream.ReadByte();
                    teleDiskSector.Flags = (byte)stream.ReadByte();
                    teleDiskSector.Crc = (byte)stream.ReadByte();

                    if(teleDiskSector.SectorNumber > maxSector) maxSector = teleDiskSector.SectorNumber;

                    if((teleDiskSector.Flags & FLAGS_SECTOR_DATALESS) != FLAGS_SECTOR_DATALESS &&
                       (teleDiskSector.Flags & FLAGS_SECTOR_SKIPPED) != FLAGS_SECTOR_SKIPPED)
                    {
                        stream.Read(dataSizeBytes, 0, 2);
                        teleDiskData.DataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                        teleDiskData.DataSize--; // Sydex decided to including dataEncoding byte as part of it
                        teleDiskData.DataEncoding = (byte)stream.ReadByte();
                        byte[] data = new byte[teleDiskData.DataSize];
                        stream.Read(data, 0, teleDiskData.DataSize);
                    }

                    if(128 << teleDiskSector.SectorSize < ImageInfo.SectorSize)
                        ImageInfo.SectorSize = (uint)(128 << teleDiskSector.SectorSize);

                    totalSectors++;
                }
            }

            totalCylinders++;
            totalHeads++;

            if(totalCylinders <= 0 || totalHeads <= 0)
                throw new ImageNotSupportedException("No cylinders or heads found");

            bool hasLeadOutOnHead0 = false;
            bool hasLeadOutOnHead1 = false;
            ImageInfo.Cylinders = (ushort)totalCylinders;
            ImageInfo.Heads = (byte)totalHeads;

            // Count sectors per track
            stream.Seek(currentPos, SeekOrigin.Begin);
            while(true)
            {
                TeleDiskTrackHeader teleDiskTrack = new TeleDiskTrackHeader
                {
                    Sectors = (byte)stream.ReadByte(),
                    Cylinder = (byte)stream.ReadByte(),
                    Head = (byte)stream.ReadByte(),
                    Crc = (byte)stream.ReadByte()
                };

                if(teleDiskTrack.Sectors == 0xFF) // End of disk image
                    break;

                if(teleDiskTrack.Sectors < ImageInfo.SectorsPerTrack)
                    if(teleDiskTrack.Cylinder + 1 == totalCylinders)
                    {
                        hasLeadOutOnHead0 |= teleDiskTrack.Head == 0;
                        hasLeadOutOnHead1 |= teleDiskTrack.Head == 1;
                        if(ImageInfo.Cylinders == totalCylinders) ImageInfo.Cylinders--;
                    }
                    else ImageInfo.SectorsPerTrack = teleDiskTrack.Sectors;
                for(byte processedSectors = 0; processedSectors < teleDiskTrack.Sectors; processedSectors++)
                {
                    TeleDiskSectorHeader teleDiskSector = new TeleDiskSectorHeader();
                    TeleDiskDataHeader teleDiskData = new TeleDiskDataHeader();
                    byte[] dataSizeBytes = new byte[2];

                    teleDiskSector.Cylinder = (byte)stream.ReadByte();
                    teleDiskSector.Head = (byte)stream.ReadByte();
                    teleDiskSector.SectorNumber = (byte)stream.ReadByte();
                    teleDiskSector.SectorSize = (byte)stream.ReadByte();
                    teleDiskSector.Flags = (byte)stream.ReadByte();
                    teleDiskSector.Crc = (byte)stream.ReadByte();

                    if((teleDiskSector.Flags & FLAGS_SECTOR_DATALESS) == FLAGS_SECTOR_DATALESS ||
                       (teleDiskSector.Flags & FLAGS_SECTOR_SKIPPED) == FLAGS_SECTOR_SKIPPED) continue;

                    stream.Read(dataSizeBytes, 0, 2);
                    teleDiskData.DataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                    teleDiskData.DataSize--; // Sydex decided to including dataEncoding byte as part of it
                    teleDiskData.DataEncoding = (byte)stream.ReadByte();
                    byte[] data = new byte[teleDiskData.DataSize];
                    stream.Read(data, 0, teleDiskData.DataSize);
                }
            }

            sectorsData = new byte[totalCylinders][][][];
            // Total sectors per track
            uint[][] spts = new uint[totalCylinders][];

            DicConsole.DebugWriteLine("TeleDisk plugin",
                                      "Found {0} cylinders and {1} heads with a maximum sector number of {2}",
                                      totalCylinders, totalHeads, maxSector);

            // Create heads
            for(int i = 0; i < totalCylinders; i++)
            {
                sectorsData[i] = new byte[totalHeads][][];
                spts[i] = new uint[totalHeads];

                for(int j = 0; j < totalHeads; j++) sectorsData[i][j] = new byte[maxSector + 1][];
            }

            // Decode the image
            stream.Seek(currentPos, SeekOrigin.Begin);
            while(true)
            {
                TeleDiskTrackHeader teleDiskTrack = new TeleDiskTrackHeader();
                byte[] tdTrackForCrc = new byte[3];
                byte tdTrackCalculatedCrc;

                teleDiskTrack.Sectors = (byte)stream.ReadByte();
                teleDiskTrack.Cylinder = (byte)stream.ReadByte();
                teleDiskTrack.Head = (byte)stream.ReadByte();
                teleDiskTrack.Crc = (byte)stream.ReadByte();

                tdTrackForCrc[0] = teleDiskTrack.Sectors;
                tdTrackForCrc[1] = teleDiskTrack.Cylinder;
                tdTrackForCrc[2] = teleDiskTrack.Head;

                tdTrackCalculatedCrc = (byte)(TeleDiskCrc(0, tdTrackForCrc) & 0xFF);

                DicConsole.DebugWriteLine("TeleDisk plugin", "Track follows");
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack cylinder: {0}\t", teleDiskTrack.Cylinder);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack head: {0}\t", teleDiskTrack.Head);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tSectors in track: {0}\t", teleDiskTrack.Sectors);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack header CRC: 0x{0:X2} (calculated 0x{1:X2})\t",
                                          teleDiskTrack.Crc, tdTrackCalculatedCrc);

                aDiskCrcHasFailed |= tdTrackCalculatedCrc != teleDiskTrack.Crc;

                if(teleDiskTrack.Sectors == 0xFF) // End of disk image
                {
                    DicConsole.DebugWriteLine("TeleDisk plugin", "End of disk image arrived");
                    DicConsole.DebugWriteLine("TeleDisk plugin", "Total of {0} data sectors, for {1} bytes",
                                              totalSectors, totalDiskSize);

                    break;
                }

                for(byte processedSectors = 0; processedSectors < teleDiskTrack.Sectors; processedSectors++)
                {
                    TeleDiskSectorHeader teleDiskSector = new TeleDiskSectorHeader();
                    TeleDiskDataHeader teleDiskData = new TeleDiskDataHeader();
                    byte[] dataSizeBytes = new byte[2];
                    byte[] decodedData;

                    teleDiskSector.Cylinder = (byte)stream.ReadByte();
                    teleDiskSector.Head = (byte)stream.ReadByte();
                    teleDiskSector.SectorNumber = (byte)stream.ReadByte();
                    teleDiskSector.SectorSize = (byte)stream.ReadByte();
                    teleDiskSector.Flags = (byte)stream.ReadByte();
                    teleDiskSector.Crc = (byte)stream.ReadByte();

                    DicConsole.DebugWriteLine("TeleDisk plugin", "\tSector follows");
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark cylinder: {0}",
                                              teleDiskSector.Cylinder);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark head: {0}", teleDiskSector.Head);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark sector number: {0}",
                                              teleDiskSector.SectorNumber);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector size: {0}", teleDiskSector.SectorSize);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector flags: 0x{0:X2}", teleDiskSector.Flags);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector CRC (plus headers): 0x{0:X2}",
                                              teleDiskSector.Crc);

                    uint lba = (uint)(teleDiskSector.Cylinder * header.Sides * ImageInfo.SectorsPerTrack +
                                      teleDiskSector.Head * ImageInfo.SectorsPerTrack +
                                      (teleDiskSector.SectorNumber - 1));
                    if((teleDiskSector.Flags & FLAGS_SECTOR_DATALESS) != FLAGS_SECTOR_DATALESS &&
                       (teleDiskSector.Flags & FLAGS_SECTOR_SKIPPED) != FLAGS_SECTOR_SKIPPED)
                    {
                        stream.Read(dataSizeBytes, 0, 2);
                        teleDiskData.DataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                        teleDiskData.DataSize--; // Sydex decided to including dataEncoding byte as part of it
                        ImageInfo.ImageSize += teleDiskData.DataSize;
                        teleDiskData.DataEncoding = (byte)stream.ReadByte();
                        byte[] data = new byte[teleDiskData.DataSize];
                        stream.Read(data, 0, teleDiskData.DataSize);
                        DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tData size (in-image): {0}",
                                                  teleDiskData.DataSize);
                        DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tData encoding: 0x{0:X2}",
                                                  teleDiskData.DataEncoding);

                        decodedData = DecodeTeleDiskData(teleDiskSector.SectorSize, teleDiskData.DataEncoding, data);

                        byte tdSectorCalculatedCrc = (byte)(TeleDiskCrc(0, decodedData) & 0xFF);

                        if(tdSectorCalculatedCrc != teleDiskSector.Crc)
                        {
                            DicConsole.DebugWriteLine("TeleDisk plugin",
                                                      "Sector {0}:{3}:{4} calculated CRC 0x{1:X2} differs from stored CRC 0x{2:X2}",
                                                      teleDiskTrack.Cylinder, tdSectorCalculatedCrc, teleDiskSector.Crc,
                                                      teleDiskTrack.Cylinder, teleDiskSector.SectorNumber);
                            if((teleDiskSector.Flags & FLAGS_SECTOR_NO_ID) != FLAGS_SECTOR_NO_ID)
                                sectorsWhereCrcHasFailed.Add(lba);
                        }
                    }
                    else decodedData = new byte[128 << teleDiskSector.SectorSize];

                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tLBA: {0}", lba);

                    if((teleDiskSector.Flags & FLAGS_SECTOR_NO_ID) == FLAGS_SECTOR_NO_ID) continue;

                    if(sectorsData[teleDiskTrack.Cylinder][teleDiskTrack.Head][teleDiskSector.SectorNumber] != null)
                        DicConsole.DebugWriteLine("TeleDisk plugin",
                                                  (teleDiskSector.Flags & FLAGS_SECTOR_DUPLICATE) ==
                                                  FLAGS_SECTOR_DUPLICATE
                                                      ? "\t\tSector {0} on cylinder {1} head {2} is duplicate, and marked so"
                                                      : "\t\tSector {0} on cylinder {1} head {2} is duplicate, but is not marked so",
                                                  teleDiskSector.SectorNumber, teleDiskSector.Cylinder,
                                                  teleDiskSector.Head);
                    else
                    {
                        sectorsData[teleDiskTrack.Cylinder][teleDiskTrack.Head][teleDiskSector.SectorNumber] =
                            decodedData;
                        totalDiskSize += (uint)decodedData.Length;
                    }
                }
            }

            MemoryStream leadOutMs = new MemoryStream();
            if(hasLeadOutOnHead0)
                for(int i = 0; i < sectorsData[totalCylinders - 1][0].Length; i++)
                    if(sectorsData[totalCylinders - 1][0][i] != null)
                        leadOutMs.Write(sectorsData[totalCylinders - 1][0][i], 0,
                                        sectorsData[totalCylinders - 1][0][i].Length);
            if(hasLeadOutOnHead1)
                for(int i = 0; i < sectorsData[totalCylinders - 1][1].Length; i++)
                    if(sectorsData[totalCylinders - 1][1][i] != null)
                        leadOutMs.Write(sectorsData[totalCylinders - 1][1][i], 0,
                                        sectorsData[totalCylinders - 1][1][i].Length);

            if(leadOutMs.Length != 0)
            {
                leadOut = leadOutMs.ToArray();
                ImageInfo.ReadableMediaTags.Add(MediaTagType.Floppy_LeadOut);
            }

            ImageInfo.Sectors = ImageInfo.Cylinders * ImageInfo.Heads * ImageInfo.SectorsPerTrack;
            ImageInfo.MediaType = DecodeTeleDiskDiskType();

            ImageInfo.XmlMediaType = XmlMediaType.BlockMedia;

            DicConsole.VerboseWriteLine("TeleDisk image contains a disk of type {0}", ImageInfo.MediaType);
            if(!string.IsNullOrEmpty(ImageInfo.ImageComments))
                DicConsole.VerboseWriteLine("TeleDisk comments: {0}", ImageInfo.ImageComments);

            inStream.Dispose();
            stream.Dispose();

            /*
            FileStream debugFs = new FileStream("debug.img", FileMode.CreateNew, FileAccess.Write);
            for(ulong i = 0; i < ImageInfo.sectors; i++)
                debugFs.Write(ReadSector(i), 0, (int)ImageInfo.sectorSize);
            debugFs.Dispose();
            */

            return true;
        }

        public override bool ImageHasPartitions()
        {
            return ImageInfo.ImageHasPartitions;
        }

        public override ulong GetImageSize()
        {
            return ImageInfo.ImageSize;
        }

        public override ulong GetSectors()
        {
            return ImageInfo.Sectors;
        }

        public override uint GetSectorSize()
        {
            return ImageInfo.SectorSize;
        }

        public override byte[] ReadSector(ulong sectorAddress)
        {
            (ushort cylinder, byte head, byte sector) = LbaToChs(sectorAddress);

            if(cylinder >= sectorsData.Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(head >= sectorsData[cylinder].Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(sector > sectorsData[cylinder][head].Length)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            return sectorsData[cylinder][head][sector];
        }

        public override byte[] ReadSectors(ulong sectorAddress, uint length)
        {
            if(sectorAddress > ImageInfo.Sectors - 1)
                throw new ArgumentOutOfRangeException(nameof(sectorAddress), "Sector address not found");

            if(sectorAddress + length > ImageInfo.Sectors)
                throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available");

            MemoryStream buffer = new MemoryStream();
            for(uint i = 0; i < length; i++)
            {
                byte[] sector = ReadSector(sectorAddress + i) ?? new byte[ImageInfo.SectorSize];
                buffer.Write(sector, 0, sector.Length);
            }

            return buffer.ToArray();
        }

        (ushort cylinder, byte head, byte sector) LbaToChs(ulong lba)
        {
            ushort cylinder = (ushort)(lba / (ImageInfo.Heads * ImageInfo.SectorsPerTrack));
            byte head = (byte)(lba / ImageInfo.SectorsPerTrack % ImageInfo.Heads);
            byte sector = (byte)(lba % ImageInfo.SectorsPerTrack + 1);

            return (cylinder, head, sector);
        }

        public override byte[] ReadSectorLong(ulong sectorAddress)
        {
            return ReadSectors(sectorAddress, 1);
        }

        public override byte[] ReadSectorsLong(ulong sectorAddress, uint length)
        {
            return ReadSectors(sectorAddress, length);
        }

        public override string GetImageFormat()
        {
            return "Sydex TeleDisk";
        }

        public override string GetImageVersion()
        {
            return ImageInfo.ImageVersion;
        }

        public override string GetImageApplication()
        {
            return ImageInfo.ImageApplication;
        }

        public override string GetImageApplicationVersion()
        {
            return ImageInfo.ImageApplicationVersion;
        }

        public override DateTime GetImageCreationTime()
        {
            return ImageInfo.ImageCreationTime;
        }

        public override DateTime GetImageLastModificationTime()
        {
            return ImageInfo.ImageLastModificationTime;
        }

        public override string GetImageName()
        {
            return ImageInfo.ImageName;
        }

        public override MediaType GetMediaType()
        {
            return ImageInfo.MediaType;
        }

        public override bool? VerifySector(ulong sectorAddress)
        {
            return !sectorsWhereCrcHasFailed.Contains(sectorAddress);
        }

        public override bool? VerifySector(ulong sectorAddress, uint track)
        {
            return null;
        }

        public override bool? VerifySectors(ulong sectorAddress, uint length, out List<ulong> failingLbas,
                                            out List<ulong> unknownLbas)
        {
            failingLbas = new List<ulong>();
            unknownLbas = new List<ulong>();

            for(ulong i = sectorAddress; i < sectorAddress + length; i++)
                if(sectorsWhereCrcHasFailed.Contains(sectorAddress)) failingLbas.Add(sectorAddress);

            return failingLbas.Count <= 0;
        }

        public override bool? VerifySectors(ulong sectorAddress, uint length, uint track, out List<ulong> failingLbas,
                                            out List<ulong> unknownLbas)
        {
            failingLbas = new List<ulong>();
            unknownLbas = new List<ulong>();

            for(ulong i = sectorAddress; i < sectorAddress + length; i++) unknownLbas.Add(i);

            return null;
        }

        public override bool? VerifyMediaImage()
        {
            return aDiskCrcHasFailed;
        }

        static ushort TeleDiskCrc(ushort crc, byte[] buffer)
        {
            int counter = 0;

            while(counter < buffer.Length)
            {
                crc ^= (ushort)((buffer[counter] & 0xFF) << 8);

                for(int i = 0; i < 8; i++)
                    if((crc & 0x8000) > 0) crc = (ushort)((crc << 1) ^ TELE_DISK_CRC_POLY);
                    else crc = (ushort)(crc << 1);

                counter++;
            }

            return crc;
        }

        static byte[] DecodeTeleDiskData(byte sectorSize, byte encodingType, byte[] encodedData)
        {
            byte[] decodedData;
            switch(sectorSize)
            {
                case SECTOR_SIZE_128:
                    decodedData = new byte[128];
                    break;
                case SECTOR_SIZE_256:
                    decodedData = new byte[256];
                    break;
                case SECTOR_SIZE_512:
                    decodedData = new byte[512];
                    break;
                case SECTOR_SIZE_1K:
                    decodedData = new byte[1024];
                    break;
                case SECTOR_SIZE_2K:
                    decodedData = new byte[2048];
                    break;
                case SECTOR_SIZE_4K:
                    decodedData = new byte[4096];
                    break;
                case SECTOR_SIZE_8K:
                    decodedData = new byte[8192];
                    break;
                default: throw new ImageNotSupportedException($"Sector size {sectorSize} is incorrect.");
            }

            switch(encodingType)
            {
                case DATA_BLOCK_COPY:
                    Array.Copy(encodedData, decodedData, decodedData.Length);
                    break;
                case DATA_BLOCK_PATTERN:
                {
                    int ins = 0;
                    int outs = 0;
                    while(ins < encodedData.Length)
                    {
                        ushort repeatNumber;
                        byte[] repeatValue = new byte[2];

                        repeatNumber = BitConverter.ToUInt16(encodedData, ins);
                        Array.Copy(encodedData, ins + 2, repeatValue, 0, 2);
                        byte[] decodedPiece = new byte[repeatNumber * 2];
                        ArrayHelpers.ArrayFill(decodedPiece, repeatValue);
                        Array.Copy(decodedPiece, 0, decodedData, outs, decodedPiece.Length);
                        ins += 4;
                        outs += decodedPiece.Length;
                    }

                    DicConsole.DebugWriteLine("TeleDisk plugin", "(Block pattern decoder): Input data size: {0} bytes",
                                              encodedData.Length);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(Block pattern decoder): Processed input: {0} bytes",
                                              ins);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(Block pattern decoder): Output data size: {0} bytes",
                                              decodedData.Length);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(Block pattern decoder): Processed Output: {0} bytes",
                                              outs);
                    break;
                }
                case DATA_BLOCK_RLE:
                {
                    int ins = 0;
                    int outs = 0;
                    while(ins < encodedData.Length)
                    {
                        byte length;
                        byte encoding;

                        encoding = encodedData[ins];
                        if(encoding == 0x00)
                        {
                            length = encodedData[ins + 1];
                            Array.Copy(encodedData, ins + 2, decodedData, outs, length);
                            ins += 2 + length;
                            outs += length;
                        }
                        else
                        {
                            length = (byte)(encoding * 2);
                            byte run = encodedData[ins + 1];
                            byte[] part = new byte[length];
                            Array.Copy(encodedData, ins + 2, part, 0, length);
                            byte[] piece = new byte[length * run];
                            ArrayHelpers.ArrayFill(piece, part);
                            Array.Copy(piece, 0, decodedData, outs, piece.Length);
                            ins += 2 + length;
                            outs += piece.Length;
                        }
                    }

                    DicConsole.DebugWriteLine("TeleDisk plugin", "(RLE decoder): Input data size: {0} bytes",
                                              encodedData.Length);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(RLE decoder): Processed input: {0} bytes", ins);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(RLE decoder): Output data size: {0} bytes",
                                              decodedData.Length);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "(RLE decoder): Processed Output: {0} bytes", outs);

                    break;
                }
                default: throw new ImageNotSupportedException($"Data encoding {encodingType} is incorrect.");
            }

            return decodedData;
        }

        MediaType DecodeTeleDiskDiskType()
        {
            switch(header.DriveType)
            {
                case DRIVE_TYPE_525_DD:
                case DRIVE_TYPE_525_HD_DD_DISK:
                case DRIVE_TYPE_525_HD:
                {
                    switch(totalDiskSize)
                    {
                        case 163840:
                        {
                            // Acorn disk uses 256 bytes/sector
                            return ImageInfo.SectorSize == 256
                                       ? MediaType.ACORN_525_SS_DD_40
                                       : MediaType.DOS_525_SS_DD_8;
                            // DOS disks use 512 bytes/sector
                        }
                        case 184320:
                        {
                            // Atari disk uses 256 bytes/sector
                            return ImageInfo.SectorSize == 256 ? MediaType.ATARI_525_DD : MediaType.DOS_525_SS_DD_9;
                            // DOS disks use 512 bytes/sector
                        }
                        case 327680:
                        {
                            // Acorn disk uses 256 bytes/sector
                            return ImageInfo.SectorSize == 256
                                       ? MediaType.ACORN_525_SS_DD_80
                                       : MediaType.DOS_525_DS_DD_8;
                            // DOS disks use 512 bytes/sector
                        }
                        case 368640: return MediaType.DOS_525_DS_DD_9;
                        case 1228800: return MediaType.DOS_525_HD;
                        case 102400: return MediaType.ACORN_525_SS_SD_40;
                        case 204800: return MediaType.ACORN_525_SS_SD_80;
                        case 655360: return MediaType.ACORN_525_DS_DD;
                        case 92160: return MediaType.ATARI_525_SD;
                        case 133120: return MediaType.ATARI_525_ED;
                        case 1310720: return MediaType.NEC_525_HD;
                        case 1261568: return MediaType.SHARP_525;
                        case 839680: return MediaType.FDFORMAT_525_DD;
                        case 1304320: return MediaType.ECMA_99_8;
                        case 1223424: return MediaType.ECMA_99_15;
                        case 1061632: return MediaType.ECMA_99_26;
                        case 80384: return MediaType.ECMA_66;
                        case 325632: return MediaType.ECMA_70;
                        case 653312: return MediaType.ECMA_78;
                        case 737280: return MediaType.ECMA_78_2;
                        default:
                        {
                            DicConsole.DebugWriteLine("TeleDisk plugin", "Unknown 5,25\" disk with {0} bytes",
                                                      totalDiskSize);
                            return MediaType.Unknown;
                        }
                    }
                }
                case DRIVE_TYPE_35_DD:
                case DRIVE_TYPE_35_ED:
                case DRIVE_TYPE_35_HD:
                {
                    switch(totalDiskSize)
                    {
                        case 322560: return MediaType.Apricot_35;
                        case 327680: return MediaType.DOS_35_SS_DD_8;
                        case 368640: return MediaType.DOS_35_SS_DD_9;
                        case 655360: return MediaType.DOS_35_DS_DD_8;
                        case 737280: return MediaType.DOS_35_DS_DD_9;
                        case 1474560: return MediaType.DOS_35_HD;
                        case 2949120: return MediaType.DOS_35_ED;
                        case 1720320: return MediaType.DMF;
                        case 1763328: return MediaType.DMF_82;
                        case 1884160: // Irreal size, seen as BIOS with TSR, 23 sectors/track
                        case 1860608: // Real data size, sum of all sectors
                            return MediaType.XDF_35;
                        case 819200: return MediaType.CBM_35_DD;
                        case 901120: return MediaType.CBM_AMIGA_35_DD;
                        case 1802240: return MediaType.CBM_AMIGA_35_HD;
                        case 1310720: return MediaType.NEC_35_HD_8;
                        case 1228800: return MediaType.NEC_35_HD_15;
                        case 1261568: return MediaType.SHARP_35;
                        default:
                        {
                            DicConsole.DebugWriteLine("TeleDisk plugin", "Unknown 3,5\" disk with {0} bytes",
                                                      totalDiskSize);
                            return MediaType.Unknown;
                        }
                    }
                }
                case DRIVE_TYPE_8_INCH:
                {
                    switch(totalDiskSize)
                    {
                        case 81664: return MediaType.IBM23FD;
                        case 242944: return MediaType.IBM33FD_128;
                        case 287488: return MediaType.IBM33FD_256;
                        case 306432: return MediaType.IBM33FD_512;
                        case 499200: return MediaType.IBM43FD_128;
                        case 574976: return MediaType.IBM43FD_256;
                        case 995072: return MediaType.IBM53FD_256;
                        case 1146624: return MediaType.IBM53FD_512;
                        case 1222400: return MediaType.IBM53FD_1024;
                        case 256256:
                            // Same size, with same disk geometry, for DEC RX01, NEC and ECMA, return ECMA
                            return MediaType.ECMA_54;
                        case 512512:
                        {
                            // DEC disk uses 256 bytes/sector
                            return ImageInfo.SectorSize == 256 ? MediaType.RX02 : MediaType.ECMA_59;
                            // ECMA disks use 128 bytes/sector
                        }
                        case 1261568: return MediaType.NEC_8_DD;
                        case 1255168: return MediaType.ECMA_69_8;
                        case 1177344: return MediaType.ECMA_69_15;
                        case 1021696: return MediaType.ECMA_69_26;
                        default:
                        {
                            DicConsole.DebugWriteLine("TeleDisk plugin", "Unknown 8\" disk with {0} bytes",
                                                      totalDiskSize);
                            return MediaType.Unknown;
                        }
                    }
                }
                default:
                {
                    DicConsole.DebugWriteLine("TeleDisk plugin", "Unknown drive type {1} with {0} bytes", totalDiskSize,
                                              header.DriveType);
                    return MediaType.Unknown;
                }
            }
        }

        public override byte[] ReadDiskTag(MediaTagType tag)
        {
            if(tag != MediaTagType.Floppy_LeadOut)
                throw new FeatureUnsupportedImageException("Feature not supported by image format");

            if(leadOut != null) return leadOut;

            throw new FeatureNotPresentImageException("Lead-out not present in disk image");
        }

        public override byte[] ReadSectorTag(ulong sectorAddress, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectorsTag(ulong sectorAddress, uint length, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override string GetImageCreator()
        {
            return ImageInfo.ImageCreator;
        }

        public override string GetImageComments()
        {
            return ImageInfo.ImageComments;
        }

        public override string GetMediaManufacturer()
        {
            return ImageInfo.MediaManufacturer;
        }

        public override string GetMediaModel()
        {
            return ImageInfo.MediaModel;
        }

        public override string GetMediaSerialNumber()
        {
            return ImageInfo.MediaSerialNumber;
        }

        public override string GetMediaBarcode()
        {
            return ImageInfo.MediaBarcode;
        }

        public override string GetMediaPartNumber()
        {
            return ImageInfo.MediaPartNumber;
        }

        public override int GetMediaSequence()
        {
            return ImageInfo.MediaSequence;
        }

        public override int GetLastDiskSequence()
        {
            return ImageInfo.LastMediaSequence;
        }

        public override string GetDriveManufacturer()
        {
            return ImageInfo.DriveManufacturer;
        }

        public override string GetDriveModel()
        {
            return ImageInfo.DriveModel;
        }

        public override string GetDriveSerialNumber()
        {
            return ImageInfo.DriveSerialNumber;
        }

        public override List<Partition> GetPartitions()
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override List<Track> GetTracks()
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override List<Track> GetSessionTracks(Session session)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override List<Track> GetSessionTracks(ushort session)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override List<Session> GetSessions()
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSector(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectorTag(ulong sectorAddress, uint track, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectors(ulong sectorAddress, uint length, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectorsTag(ulong sectorAddress, uint length, uint track, SectorTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectorLong(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public override byte[] ReadSectorsLong(ulong sectorAddress, uint length, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        struct TeleDiskHeader
        {
            /// <summary>"TD" or "td" depending on compression</summary>
            public ushort Signature;
            /// <summary>Sequence, but TeleDisk seems to complaing if != 0</summary>
            public byte Sequence;
            /// <summary>Random, same byte for all disks in the same set</summary>
            public byte DiskSet;
            /// <summary>TeleDisk version, major in high nibble, minor in low nibble</summary>
            public byte Version;
            /// <summary>Data rate</summary>
            public byte DataRate;
            /// <summary>BIOS drive type</summary>
            public byte DriveType;
            /// <summary>Stepping used</summary>
            public byte Stepping;
            /// <summary>If set means image only allocates sectors marked in-use by FAT12</summary>
            public byte DosAllocation;
            /// <summary>Sides of disk</summary>
            public byte Sides;
            /// <summary>CRC of all the previous</summary>
            public ushort Crc;
        }

        struct TeleDiskCommentBlockHeader
        {
            /// <summary>CRC of comment block after crc field</summary>
            public ushort Crc;
            /// <summary>Length of comment</summary>
            public ushort Length;
            public byte Year;
            public byte Month;
            public byte Day;
            public byte Hour;
            public byte Minute;
            public byte Second;
        }

        struct TeleDiskTrackHeader
        {
            /// <summary>Sectors in the track, 0xFF if end of disk image (there is no spoon)</summary>
            public byte Sectors;
            /// <summary>Cylinder the head was on</summary>
            public byte Cylinder;
            /// <summary>Head/side used</summary>
            public byte Head;
            /// <summary>Lower byte of CRC of previous fields</summary>
            public byte Crc;
        }

        struct TeleDiskSectorHeader
        {
            /// <summary>Cylinder as stored on sector address mark</summary>
            public byte Cylinder;
            /// <summary>Head as stored on sector address mark</summary>
            public byte Head;
            /// <summary>Sector number as stored on sector address mark</summary>
            public byte SectorNumber;
            /// <summary>Sector size</summary>
            public byte SectorSize;
            /// <summary>Sector flags</summary>
            public byte Flags;
            /// <summary>Lower byte of TeleDisk CRC of sector header, data header and data block</summary>
            public byte Crc;
        }

        struct TeleDiskDataHeader
        {
            /// <summary>Size of all data (encoded) + next field (1)</summary>
            public ushort DataSize;
            /// <summary>Encoding used for data block</summary>
            public byte DataEncoding;
        }

        #region LZH decompression from MAME
        /* This region is under following license:
         * Copyright © 2017 Miodrag Milanovic
         * Adapted to C#, Copyright © 2017 Natalia Portillo
         * 
         * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
         * 
         * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
         * 
         * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation
         * and/or other materials provided with the distribution.
         * 
         * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software
         * without specific prior written permission.
         * 
         * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
         * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
         * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
         * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
         * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
         * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
         */

        /*
         * Based on Japanese version 29-NOV-1988
         * LZSS coded by Haruhiko OKUMURA
         * Adaptive Huffman Coding coded by Haruyasu YOSHIZAKI
         * Edited and translated to English by Kenji RIKITAKE
         */

        const int BUFSZ = 512;

        /* LZSS Parameters */

        const int N = 4096; /* Size of string buffer */
        const int F = 60; /* Size of look-ahead buffer */
        const int THRESHOLD = 2;
        const int NIL = N; /* End of tree's node  */

        /* Huffman coding parameters */

        const int N_CHAR = 256 - THRESHOLD + F;
        /* character code (= 0..N_CHAR-1) */
        const int T = N_CHAR * 2 - 1; /* Size of table */
        const int ROOT = T - 1; /* root position */
        const int MAX_FREQ = 0x8000;
        /* update when cumulative frequency */
        /* reaches to this value */

        struct Tdlzhuf
        {
            public ushort R,
                          Bufcnt,
                          Bufndx,
                          Bufpos, // string buffer
                          // the following to allow block reads from input in next_word()
                          Ibufcnt,
                          Ibufndx; // input buffer counters
            public byte[] Inbuf; // input buffer
        }

        Tdlzhuf tdctl;
        byte[] text_buf = new byte[N + F - 1];
        ushort[] freq = new ushort[T + 1]; /* cumulative freq table */

        /*
         * pointing parent nodes.
         * area [T..(T + N_CHAR - 1)] are pointers for leaves
         */
        short[] prnt = new short[T + N_CHAR];

        /* pointing children nodes (son[], son[] + 1)*/
        short[] son = new short[T];

        ushort getbuf;
        byte getlen;

        long data_read(out byte[] buf, long size)
        {
            if(size > inStream.Length - inStream.Position) size = inStream.Length - inStream.Position;

            buf = new byte[size];
            inStream.Read(buf, 0, (int)size);
            return size;
        }

        /*
         * Tables for encoding/decoding upper 6 bits of
         * sliding dictionary pointer
         */

        /* decoder table */
        readonly byte[] d_code =
        {
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01,
            0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
            0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
            0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05,
            0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x07, 0x07, 0x07, 0x07,
            0x07, 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09,
            0x09, 0x09, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B,
            0x0C, 0x0C, 0x0C, 0x0C, 0x0D, 0x0D, 0x0D, 0x0D, 0x0E, 0x0E, 0x0E, 0x0E, 0x0F, 0x0F, 0x0F, 0x0F, 0x10, 0x10,
            0x10, 0x10, 0x11, 0x11, 0x11, 0x11, 0x12, 0x12, 0x12, 0x12, 0x13, 0x13, 0x13, 0x13, 0x14, 0x14, 0x14, 0x14,
            0x15, 0x15, 0x15, 0x15, 0x16, 0x16, 0x16, 0x16, 0x17, 0x17, 0x17, 0x17, 0x18, 0x18, 0x19, 0x19, 0x1A, 0x1A,
            0x1B, 0x1B, 0x1C, 0x1C, 0x1D, 0x1D, 0x1E, 0x1E, 0x1F, 0x1F, 0x20, 0x20, 0x21, 0x21, 0x22, 0x22, 0x23, 0x23,
            0x24, 0x24, 0x25, 0x25, 0x26, 0x26, 0x27, 0x27, 0x28, 0x28, 0x29, 0x29, 0x2A, 0x2A, 0x2B, 0x2B, 0x2C, 0x2C,
            0x2D, 0x2D, 0x2E, 0x2E, 0x2F, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
            0x3C, 0x3D, 0x3E, 0x3F
        };

        readonly byte[] d_len =
        {
            0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
            0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04,
            0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
            0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
            0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
            0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
            0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
            0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
            0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
            0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
            0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
            0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
            0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
            0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
            0x08, 0x08, 0x08, 0x08
        };

        int next_word()
        {
            if(tdctl.Ibufndx >= tdctl.Ibufcnt)
            {
                tdctl.Ibufndx = 0;
                tdctl.Ibufcnt = (ushort)data_read(out tdctl.Inbuf, BUFSZ);
                if(tdctl.Ibufcnt <= 0) return -1;
            }

            while(getlen <= 8)
            {
                // typically reads a word at a time
                getbuf |= (ushort)(tdctl.Inbuf[tdctl.Ibufndx++] << (8 - getlen));
                getlen += 8;
            }

            return 0;
        }

        int GetBit() /* get one bit */
        {
            short i;
            if(next_word() < 0) return -1;

            i = (short)getbuf;
            getbuf <<= 1;
            getlen--;
            return i < 0 ? 1 : 0;
        }

        int GetByte() /* get a byte */
        {
            ushort i;
            if(next_word() != 0) return -1;

            i = getbuf;
            getbuf <<= 8;
            getlen -= 8;
            i = (ushort)(i >> 8);
            return i;
        }

        /* initialize freq tree */

        void StartHuff()
        {
            int i, j;

            for(i = 0; i < N_CHAR; i++)
            {
                freq[i] = 1;
                son[i] = (short)(i + T);
                prnt[i + T] = (short)i;
            }

            i = 0;
            j = N_CHAR;
            while(j <= ROOT)
            {
                freq[j] = (ushort)(freq[i] + freq[i + 1]);
                son[j] = (short)i;
                prnt[i] = prnt[i + 1] = (short)j;
                i += 2;
                j++;
            }

            freq[T] = 0xffff;
            prnt[ROOT] = 0;
        }

        /* reconstruct freq tree */

        void Reconst()
        {
            short i, j, k;

            /* halven cumulative freq for leaf nodes */
            j = 0;
            for(i = 0; i < T; i++)
                if(son[i] >= T)
                {
                    freq[j] = (ushort)((freq[i] + 1) / 2);
                    son[j] = son[i];
                    j++;
                }
            /* make a tree : first, connect children nodes */
            for(i = 0, j = N_CHAR; j < T; i += 2, j++)
            {
                k = (short)(i + 1);
                ushort f = freq[j] = (ushort)(freq[i] + freq[k]);
                for(k = (short)(j - 1); f < freq[k]; k--) { }

                k++;
                ushort l = (ushort)((j - k) * 2);

                Array.ConstrainedCopy(freq, k, freq, k + 1, l);
                freq[k] = f;
                Array.ConstrainedCopy(son, k, son, k + 1, l);
                son[k] = i;
            }
            /* connect parent nodes */
            for(i = 0; i < T; i++)
                if((k = son[i]) >= T) prnt[k] = i;
                else prnt[k] = prnt[k + 1] = i;
        }

        /* update freq tree */

        void Update(int c)
        {
            if(freq[ROOT] == MAX_FREQ) Reconst();
            c = prnt[c + T];
            do
            {
                int k = ++freq[c];

                /* swap nodes to keep the tree freq-ordered */
                int l;
                if(k <= freq[l = c + 1]) continue;

                while(k > freq[++l]) { }

                l--;
                freq[c] = freq[l];
                freq[l] = (ushort)k;

                int i = son[c];
                prnt[i] = (short)l;
                if(i < T) prnt[i + 1] = (short)l;

                int j = son[l];
                son[l] = (short)i;

                prnt[j] = (short)c;
                if(j < T) prnt[j + 1] = (short)c;
                son[c] = (short)j;

                c = l;
            }
            while((c = prnt[c]) != 0); /* do it until reaching the root */
        }

        short DecodeChar()
        {
            ushort c;

            c = (ushort)son[ROOT];

            /*
             * start searching tree from the root to leaves.
             * choose node #(son[]) if input bit == 0
             * else choose #(son[]+1) (input bit == 1)
             */
            while(c < T)
            {
                int ret;
                if((ret = GetBit()) < 0) return -1;

                c += (ushort)ret;
                c = (ushort)son[c];
            }

            c -= T;
            Update(c);
            return (short)c;
        }

        short DecodePosition()
        {
            short bit;
            ushort i, j, c;

            /* decode upper 6 bits from given table */
            if((bit = (short)GetByte()) < 0) return -1;

            i = (ushort)bit;
            c = (ushort)(d_code[i] << 6);
            j = d_len[i];

            /* input lower 6 bits directly */
            j -= 2;
            while(j-- > 0)
            {
                if((bit = (short)GetBit()) < 0) return -1;

                i = (ushort)((i << 1) + bit);
            }

            return (short)(c | (i & 0x3f));
        }

        /* DeCompression

        split out initialization code to init_Decode()

        */

        void init_Decode()
        {
            int i;
            getbuf = 0;
            getlen = 0;
            tdctl = new Tdlzhuf();
            tdctl.Ibufcnt = tdctl.Ibufndx = 0; // input buffer is empty
            tdctl.Bufcnt = 0;
            StartHuff();
            for(i = 0; i < N - F; i++) text_buf[i] = 0x20;

            tdctl.R = N - F;
        }

        int Decode(out byte[] buf, int len) /* Decoding/Uncompressing */
        {
            short c;
            buf = new byte[len];
            int count; // was an unsigned long, seems unnecessary
            for(count = 0; count < len;)
                if(tdctl.Bufcnt == 0)
                {
                    if((c = DecodeChar()) < 0) return count; // fatal error

                    if(c < 256)
                    {
                        buf[count] = (byte)c;
                        text_buf[tdctl.R++] = (byte)c;
                        tdctl.R &= N - 1;
                        count++;
                    }
                    else
                    {
                        short pos;
                        if((pos = DecodePosition()) < 0) return count; // fatal error

                        tdctl.Bufpos = (ushort)((tdctl.R - pos - 1) & (N - 1));
                        tdctl.Bufcnt = (ushort)(c - 255 + THRESHOLD);
                        tdctl.Bufndx = 0;
                    }
                }
                else
                {
                    // still chars from last string
                    while(tdctl.Bufndx < tdctl.Bufcnt && count < len)
                    {
                        c = text_buf[(tdctl.Bufpos + tdctl.Bufndx) & (N - 1)];
                        buf[count] = (byte)c;
                        tdctl.Bufndx++;
                        text_buf[tdctl.R++] = (byte)c;
                        tdctl.R &= N - 1;
                        count++;
                    }
                    // reset bufcnt after copy string from text_buf[]
                    if(tdctl.Bufndx >= tdctl.Bufcnt) tdctl.Bufndx = tdctl.Bufcnt = 0;
                }

            return count; // count == len, success
        }
        #endregion LZH decompression from MAME
    }
}