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 DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;

namespace DiscImageChef.ImagePlugins
{
    // Created following notes from Dave Dunfield
    // http://www.classiccmp.org/dunfield/img54306/td0notes.txt
    public class TeleDisk : ImagePlugin
    {
        #region Internal Structures
        struct TD0Header
        {
            /// <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 TDCommentBlockHeader
        {
            /// <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 TDTrackHeader
        {
            /// <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 TDSectorHeader
        {
            /// <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 TDDataHeader
        {
            /// <summary>Size of all data (encoded) + next field (1)</summary>
            public ushort dataSize;
            /// <summary>Encoding used for data block</summary>
            public byte dataEncoding;
        }
        #endregion

        #region Internal Constants
        // "TD" as little endian uint.
        const ushort tdMagic = 0x4454;
        // "td" as little endian uint. Means whole file is compressed (aka Advanced Compression)
        const ushort tdAdvCompMagic = 0x6474;

        // DataRates
        const byte DataRate250kbps = 0x00;
        const byte DataRate300kbps = 0x01;
        const byte DataRate500kbps = 0x02;

        // TeleDisk drive types
        const byte DriveType525HD_DDDisk = 0x00;
        const byte DriveType525HD = 0x01;
        const byte DriveType525DD = 0x02;
        const byte DriveType35DD = 0x03;
        const byte DriveType35HD = 0x04;
        const byte DriveType8inch = 0x05;
        const byte DriveType35ED = 0x06;

        // Stepping
        const byte SteppingSingle = 0x00;
        const byte SteppingDouble = 0x01;
        const byte SteppingEvenOnly = 0x02;
        // If this bit is set, there is a comment block
        const byte CommentBlockPresent = 0x80;

        // CRC polynomial
        const ushort TeleDiskCRCPoly = 0xA097;

        // Sector sizes table
        const byte SectorSize128 = 0x00;
        const byte SectorSize256 = 0x01;
        const byte SectorSize512 = 0x02;
        const byte SectorSize1K = 0x03;
        const byte SectorSize2K = 0x04;
        const byte SectorSize4K = 0x05;
        const byte SectorSize8K = 0x06;

        // Flags
        // Address mark repeats inside same track
        const byte FlagsSectorDuplicate = 0x01;
        // Sector gave CRC error on reading
        const byte FlagsSectorCRCError = 0x02;
        // Address mark indicates deleted sector
        const byte FlagsSectorDeleted = 0x04;
        // Sector skipped as FAT said it's unused
        const byte FlagsSectorSkipped = 0x10;
        // There was an address mark, but no data following
        const byte FlagsSectorDataless = 0x20;
        // There was data without address mark
        const byte FlagsSectorNoID = 0x40;

        // Data block encodings
        // Data is copied as is
        const byte dataBlockCopy = 0x00;
        // Data is encoded as a pair of len.value uint16s
        const byte dataBlockPattern = 0x01;
        // Data is encoded as RLE
        const byte dataBlockRLE = 0x02;
        #endregion

        #region Internal variables
        TD0Header header;
        TDCommentBlockHeader commentHeader;
        byte[] commentBlock;
        // LBA, data
        uint totalDiskSize;
        bool ADiskCRCHasFailed;
        List<ulong> SectorsWhereCRCHasFailed;
        // Cylinder by head, sector data matrix
        byte[][][][] sectorsData;
        Stream inStream;
        byte[] leadOut;
        #endregion

        public TeleDisk()
        {
            Name = "Sydex TeleDisk";
            PluginUUID = new Guid("0240B7B1-E959-4CDC-B0BD-386D6E467B88");
            ImageInfo = new ImageInfo();
            ImageInfo.readableSectorTags = new List<SectorTagType>();
            ImageInfo.readableMediaTags = new List<MediaTagType>();
            ImageInfo.imageHasPartitions = false;
            ImageInfo.imageHasSessions = false;
            ImageInfo.imageApplication = "Sydex TeleDisk";
            ImageInfo.imageComments = null;
            ImageInfo.imageCreator = null;
            ImageInfo.mediaManufacturer = null;
            ImageInfo.mediaModel = null;
            ImageInfo.mediaSerialNumber = null;
            ImageInfo.mediaBarcode = null;
            ImageInfo.mediaPartNumber = null;
            ImageInfo.mediaSequence = 0;
            ImageInfo.lastMediaSequence = 0;
            ImageInfo.driveManufacturer = null;
            ImageInfo.driveModel = null;
            ImageInfo.driveSerialNumber = null;
            ImageInfo.driveFirmwareRevision = null;
            ADiskCRCHasFailed = false;
            SectorsWhereCRCHasFailed = new List<ulong>();
        }

        public override bool IdentifyImage(Filter imageFilter)
        {
            header = new TD0Header();
            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 != tdMagic && header.signature != tdAdvCompMagic) 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 != DataRate250kbps && header.dataRate != DataRate300kbps &&
               header.dataRate != DataRate500kbps) return false;

            if(header.driveType != DriveType35DD && header.driveType != DriveType35ED &&
               header.driveType != DriveType35HD && header.driveType != DriveType525DD &&
               header.driveType != DriveType525HD && header.driveType != DriveType525HD_DDDisk &&
               header.driveType != DriveType8inch) return false;

            return true;
        }

        public override bool OpenImage(Filter imageFilter)
        {
            header = new TD0Header();
            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 != tdMagic && header.signature != tdAdvCompMagic) 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 = string.Format("{0}.{1}", (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 != DataRate250kbps && header.dataRate != DataRate300kbps &&
               header.dataRate != DataRate500kbps) return false;

            if(header.driveType != DriveType35DD && header.driveType != DriveType35ED &&
               header.driveType != DriveType35HD && header.driveType != DriveType525DD &&
               header.driveType != DriveType525HD && header.driveType != DriveType525HD_DDDisk &&
               header.driveType != DriveType8inch) return false;

            if(header.signature == tdAdvCompMagic)
            {
                int rd;
                byte[] obuf = new byte[BUFSZ];
                inStream.Seek(12, SeekOrigin.Begin);
                stream.Seek(12, SeekOrigin.Begin);
                init_Decode();
                do { if((rd = Decode(out 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);
                copybuf = null;
            }

            stream.Seek(12, SeekOrigin.Begin);

            ImageInfo.imageCreationTime = DateTime.MinValue;

            if((header.stepping & CommentBlockPresent) == CommentBlockPresent)
            {
                commentHeader = new TDCommentBlockHeader();

                byte[] commentHeaderBytes = new byte[10];
                byte[] commentBlockForCRC;

                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);

                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 = System.Text.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)
            {
                TDTrackHeader TDTrack = new TDTrackHeader();

                TDTrack.sectors = (byte)stream.ReadByte();
                TDTrack.cylinder = (byte)stream.ReadByte();
                TDTrack.head = (byte)stream.ReadByte();
                TDTrack.crc = (byte)stream.ReadByte();

                if(TDTrack.cylinder > totalCylinders) totalCylinders = TDTrack.cylinder;
                if(TDTrack.head > totalHeads) totalHeads = TDTrack.head;

                if(TDTrack.sectors == 0xFF) // End of disk image
                    break;

                for(byte processedSectors = 0; processedSectors < TDTrack.sectors; processedSectors++)
                {
                    TDSectorHeader TDSector = new TDSectorHeader();
                    TDDataHeader TDData = new TDDataHeader();
                    byte[] dataSizeBytes = new byte[2];
                    byte[] data;

                    TDSector.cylinder = (byte)stream.ReadByte();
                    TDSector.head = (byte)stream.ReadByte();
                    TDSector.sectorNumber = (byte)stream.ReadByte();
                    TDSector.sectorSize = (byte)stream.ReadByte();
                    TDSector.flags = (byte)stream.ReadByte();
                    TDSector.crc = (byte)stream.ReadByte();

                    if(TDSector.sectorNumber > maxSector) maxSector = TDSector.sectorNumber;

                    if((TDSector.flags & FlagsSectorDataless) != FlagsSectorDataless &&
                       (TDSector.flags & FlagsSectorSkipped) != FlagsSectorSkipped)
                    {
                        stream.Read(dataSizeBytes, 0, 2);
                        TDData.dataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                        TDData.dataSize--; // Sydex decided to including dataEncoding byte as part of it
                        TDData.dataEncoding = (byte)stream.ReadByte();
                        data = new byte[TDData.dataSize];
                        stream.Read(data, 0, TDData.dataSize);
                    }

                    if(128 << TDSector.sectorSize < ImageInfo.sectorSize)
                        ImageInfo.sectorSize = (uint)(128 << TDSector.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)
            {
                TDTrackHeader TDTrack = new TDTrackHeader();

                TDTrack.sectors = (byte)stream.ReadByte();
                TDTrack.cylinder = (byte)stream.ReadByte();
                TDTrack.head = (byte)stream.ReadByte();
                TDTrack.crc = (byte)stream.ReadByte();

                if(TDTrack.sectors == 0xFF) // End of disk image
                    break;

                if(TDTrack.sectors < ImageInfo.sectorsPerTrack)
                {
                    if(TDTrack.cylinder + 1 == totalCylinders)
                    {
                        hasLeadOutOnHead0 |= TDTrack.head == 0;
                        hasLeadOutOnHead1 |= TDTrack.head == 1;
                        if(ImageInfo.cylinders == totalCylinders) ImageInfo.cylinders--;
                    }
                    else ImageInfo.sectorsPerTrack = TDTrack.sectors;
                }
                for(byte processedSectors = 0; processedSectors < TDTrack.sectors; processedSectors++)
                {
                    TDSectorHeader TDSector = new TDSectorHeader();
                    TDDataHeader TDData = new TDDataHeader();
                    byte[] dataSizeBytes = new byte[2];
                    byte[] data;

                    TDSector.cylinder = (byte)stream.ReadByte();
                    TDSector.head = (byte)stream.ReadByte();
                    TDSector.sectorNumber = (byte)stream.ReadByte();
                    TDSector.sectorSize = (byte)stream.ReadByte();
                    TDSector.flags = (byte)stream.ReadByte();
                    TDSector.crc = (byte)stream.ReadByte();

                    if((TDSector.flags & FlagsSectorDataless) != FlagsSectorDataless &&
                       (TDSector.flags & FlagsSectorSkipped) != FlagsSectorSkipped)
                    {
                        stream.Read(dataSizeBytes, 0, 2);
                        TDData.dataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                        TDData.dataSize--; // Sydex decided to including dataEncoding byte as part of it
                        TDData.dataEncoding = (byte)stream.ReadByte();
                        data = new byte[TDData.dataSize];
                        stream.Read(data, 0, TDData.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)
            {
                TDTrackHeader TDTrack = new TDTrackHeader();
                byte[] TDTrackForCRC = new byte[3];
                byte TDTrackCalculatedCRC;

                TDTrack.sectors = (byte)stream.ReadByte();
                TDTrack.cylinder = (byte)stream.ReadByte();
                TDTrack.head = (byte)stream.ReadByte();
                TDTrack.crc = (byte)stream.ReadByte();

                TDTrackForCRC[0] = TDTrack.sectors;
                TDTrackForCRC[1] = TDTrack.cylinder;
                TDTrackForCRC[2] = TDTrack.head;

                TDTrackCalculatedCRC = (byte)(TeleDiskCRC(0, TDTrackForCRC) & 0xFF);

                DicConsole.DebugWriteLine("TeleDisk plugin", "Track follows");
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack cylinder: {0}\t", TDTrack.cylinder);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack head: {0}\t", TDTrack.head);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tSectors in track: {0}\t", TDTrack.sectors);
                DicConsole.DebugWriteLine("TeleDisk plugin", "\tTrack header CRC: 0x{0:X2} (calculated 0x{1:X2})\t",
                                          TDTrack.crc, TDTrackCalculatedCRC);

                ADiskCRCHasFailed |= TDTrackCalculatedCRC != TDTrack.crc;

                if(TDTrack.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 < TDTrack.sectors; processedSectors++)
                {
                    TDSectorHeader TDSector = new TDSectorHeader();
                    TDDataHeader TDData = new TDDataHeader();
                    byte[] dataSizeBytes = new byte[2];
                    byte[] data;
                    byte[] decodedData;

                    TDSector.cylinder = (byte)stream.ReadByte();
                    TDSector.head = (byte)stream.ReadByte();
                    TDSector.sectorNumber = (byte)stream.ReadByte();
                    TDSector.sectorSize = (byte)stream.ReadByte();
                    TDSector.flags = (byte)stream.ReadByte();
                    TDSector.crc = (byte)stream.ReadByte();

                    DicConsole.DebugWriteLine("TeleDisk plugin", "\tSector follows");
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark cylinder: {0}", TDSector.cylinder);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark head: {0}", TDSector.head);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tAddressMark sector number: {0}",
                                              TDSector.sectorNumber);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector size: {0}", TDSector.sectorSize);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector flags: 0x{0:X2}", TDSector.flags);
                    DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tSector CRC (plus headers): 0x{0:X2}",
                                              TDSector.crc);

                    uint LBA = (uint)((TDSector.cylinder * header.sides * ImageInfo.sectorsPerTrack) +
                                      (TDSector.head * ImageInfo.sectorsPerTrack) + (TDSector.sectorNumber - 1));
                    if((TDSector.flags & FlagsSectorDataless) != FlagsSectorDataless &&
                       (TDSector.flags & FlagsSectorSkipped) != FlagsSectorSkipped)
                    {
                        stream.Read(dataSizeBytes, 0, 2);
                        TDData.dataSize = BitConverter.ToUInt16(dataSizeBytes, 0);
                        TDData.dataSize--; // Sydex decided to including dataEncoding byte as part of it
                        ImageInfo.imageSize += TDData.dataSize;
                        TDData.dataEncoding = (byte)stream.ReadByte();
                        data = new byte[TDData.dataSize];
                        stream.Read(data, 0, TDData.dataSize);
                        DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tData size (in-image): {0}", TDData.dataSize);
                        DicConsole.DebugWriteLine("TeleDisk plugin", "\t\tData encoding: 0x{0:X2}",
                                                  TDData.dataEncoding);

                        decodedData = DecodeTeleDiskData(TDSector.sectorSize, TDData.dataEncoding, data);

                        byte TDSectorCalculatedCRC = (byte)(TeleDiskCRC(0, decodedData) & 0xFF);

                        if(TDSectorCalculatedCRC != TDSector.crc)
                        {
                            DicConsole.DebugWriteLine("TeleDisk plugin",
                                                      "Sector {0}:{3}:{4} calculated CRC 0x{1:X2} differs from stored CRC 0x{2:X2}",
                                                      TDTrack.cylinder, TDSectorCalculatedCRC, TDSector.crc,
                                                      TDTrack.cylinder, TDSector.sectorNumber);
                            if((TDSector.flags & FlagsSectorNoID) != FlagsSectorNoID) SectorsWhereCRCHasFailed.Add(LBA);
                        }
                    }
                    else decodedData = new byte[128 << TDSector.sectorSize];

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

                    if((TDSector.flags & FlagsSectorNoID) != FlagsSectorNoID)
                    {
                        if(sectorsData[TDTrack.cylinder][TDTrack.head][TDSector.sectorNumber] != null)
                        {
                            if((TDSector.flags & FlagsSectorDuplicate) == FlagsSectorDuplicate)
                            {
                                DicConsole.DebugWriteLine("TeleDisk plugin",
                                                          "\t\tSector {0} on cylinder {1} head {2} is duplicate, and marked so",
                                                          TDSector.sectorNumber, TDSector.cylinder, TDSector.head);
                            }
                            else
                            {
                                DicConsole.DebugWriteLine("TeleDisk plugin",
                                                          "\t\tSector {0} on cylinder {1} head {2} is duplicate, but is not marked so",
                                                          TDSector.sectorNumber, TDSector.cylinder, TDSector.head);
                            }
                        }
                        else
                        {
                            sectorsData[TDTrack.cylinder][TDTrack.head][TDSector.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);
                if(sector == null) sector = 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;
        }

        #region Private methods
        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) ^ TeleDiskCRCPoly);
                    else crc = (ushort)(crc << 1);
                }

                counter++;
            }

            return crc;
        }

        static byte[] DecodeTeleDiskData(byte sectorSize, byte encodingType, byte[] encodedData)
        {
            byte[] decodedData;
            switch(sectorSize)
            {
                case SectorSize128:
                    decodedData = new byte[128];
                    break;
                case SectorSize256:
                    decodedData = new byte[256];
                    break;
                case SectorSize512:
                    decodedData = new byte[512];
                    break;
                case SectorSize1K:
                    decodedData = new byte[1024];
                    break;
                case SectorSize2K:
                    decodedData = new byte[2048];
                    break;
                case SectorSize4K:
                    decodedData = new byte[4096];
                    break;
                case SectorSize8K:
                    decodedData = new byte[8192];
                    break;
                default:
                    throw new ImageNotSupportedException(string.Format("Sector size {0} is incorrect.", sectorSize));
            }

            switch(encodingType)
            {
                case dataBlockCopy:
                    Array.Copy(encodedData, decodedData, decodedData.Length);
                    break;
                case dataBlockPattern:
                {
                    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 dataBlockRLE:
                {
                    int ins = 0;
                    int outs = 0;
                    while(ins < encodedData.Length)
                    {
                        byte Run;
                        byte Length;
                        byte Encoding;
                        byte[] Piece;

                        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);
                            Run = encodedData[ins + 1];
                            byte[] Part = new byte[Length];
                            Array.Copy(encodedData, ins + 2, Part, 0, Length);
                            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(string.Format("Data encoding {0} is incorrect.",
                                                                       encodingType));
            }

            return decodedData;
        }

        MediaType DecodeTeleDiskDiskType()
        {
            switch(header.driveType)
            {
                case DriveType525DD:
                case DriveType525HD_DDDisk:
                case DriveType525HD:
                {
                    switch(totalDiskSize)
                    {
                        case 163840:
                        {
                            // Acorn disk uses 256 bytes/sector
                            if(ImageInfo.sectorSize == 256) return MediaType.ACORN_525_SS_DD_40;
                            // DOS disks use 512 bytes/sector
                            return MediaType.DOS_525_SS_DD_8;
                        }
                        case 184320:
                        {
                            // Atari disk uses 256 bytes/sector
                            if(ImageInfo.sectorSize == 256) return MediaType.ATARI_525_DD;
                            // DOS disks use 512 bytes/sector
                            return MediaType.DOS_525_SS_DD_9;
                        }
                        case 327680:
                        {
                            // Acorn disk uses 256 bytes/sector
                            if(ImageInfo.sectorSize == 256) return MediaType.ACORN_525_SS_DD_80;
                            // DOS disks use 512 bytes/sector
                            return MediaType.DOS_525_DS_DD_8;
                        }
                        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 DriveType35DD:
                case DriveType35ED:
                case DriveType35HD:
                {
                    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 DriveType8inch:
                {
                    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
                            if(ImageInfo.sectorSize == 256) return MediaType.RX02;
                            // ECMA disks use 128 bytes/sector
                            return MediaType.ECMA_59;
                        }
                        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)
            {
                if(leadOut != null) return leadOut;

                throw new FeatureNotPresentImageException("Lead-out not present in disk image");
            }
            else throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }
        #endregion

        #region Unsupported features
        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");
        }
        #endregion Unsupported features

        #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 R = (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--;
            if(i < 0) return (1);
            else return (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 ((int)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 <= R)
            {
                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[R] = 0;
        }

        /* reconstruct freq tree */

        void reconst()
        {
            short i, j, k;
            ushort f, l;

            /* 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);
                f = freq[j] = (ushort)(freq[i] + freq[k]);
                for(k = (short)(j - 1); f < freq[k]; k--) { }

                ;
                k++;
                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)
        {
            int i, j, k, l;

            if(freq[R] == MAX_FREQ) { reconst(); }
            c = prnt[c + T];
            do
            {
                k = ++freq[c];

                /* swap nodes to keep the tree freq-ordered */
                if(k > freq[l = c + 1])
                {
                    while(k > freq[++l]) { }

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

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

                    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()
        {
            int ret;
            ushort c;

            c = (ushort)son[R];

            /*
             * 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)
            {
                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, pos;
            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
                    {
                        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
    }
}