Aaru/DiscImageChef.DiscImages/Apple2MG.cs

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename       : Apple2MG.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Manages XGS emulator 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
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;

namespace DiscImageChef.DiscImages
{
    public class Apple2Mg : IWritableImage
    {
        /// <summary>
        ///     Magic number, "2IMG"
        /// </summary>
        const uint MAGIC = 0x474D4932;
        /// <summary>
        ///     Disk image created by ASIMOV2, "!nfc"
        /// </summary>
        const uint CREATOR_ASIMOV = 0x63666E21;
        /// <summary>
        ///     Disk image created by Bernie ][ the Rescue, "B2TR"
        /// </summary>
        const uint CREATOR_BERNIE = 0x52543242;
        /// <summary>
        ///     Disk image created by Catakig, "CTKG"
        /// </summary>
        const uint CREATOR_CATAKIG = 0x474B5443;
        /// <summary>
        ///     Disk image created by Sheppy's ImageMaker, "ShIm"
        /// </summary>
        const uint CREATOR_SHEPPY = 0x6D496853;
        /// <summary>
        ///     Disk image created by Sweet16, "WOOF"
        /// </summary>
        const uint CREATOR_SWEET = 0x464F4F57;
        /// <summary>
        ///     Disk image created by XGS, "XGS!"
        /// </summary>
        const uint CREATOR_XGS = 0x21534758;
        /// <summary>
        ///     Disk image created by CiderPress, "CdrP"
        /// </summary>
        const uint CREATOR_CIDER = 0x50726443;
        /// <summary>
        ///     Disk image created by DiscImageChef, "dic "
        /// </summary>
        const uint CREATOR_DIC = 0x20636964;

        const    uint  LOCKED_DISK         = 0x80000000;
        const    uint  VALID_VOLUME_NUMBER = 0x00000100;
        const    uint  VOLUME_NUMBER_MASK  = 0x000000FF;
        readonly int[] deinterleave        = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};

        readonly int[] interleave = {0, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 15};

        IFilter     a2MgImageFilter;
        byte[]      decodedImage;
        A2ImgHeader imageHeader;
        ImageInfo   imageInfo;
        FileStream  writingStream;

        public Apple2Mg()
        {
            imageInfo = new ImageInfo
            {
                ReadableSectorTags    = new List<SectorTagType>(),
                ReadableMediaTags     = new List<MediaTagType>(),
                HasPartitions         = false,
                HasSessions           = false,
                Version               = null,
                Application           = null,
                ApplicationVersion    = null,
                Creator               = null,
                Comments              = null,
                MediaManufacturer     = null,
                MediaModel            = null,
                MediaSerialNumber     = null,
                MediaBarcode          = null,
                MediaPartNumber       = null,
                MediaSequence         = 0,
                LastMediaSequence     = 0,
                DriveManufacturer     = null,
                DriveModel            = null,
                DriveSerialNumber     = null,
                DriveFirmwareRevision = null
            };
        }

        public ImageInfo Info => imageInfo;

        public string Name => "Apple 2IMG";
        public Guid   Id   => new Guid("CBAF8824-BA5F-415F-953A-19A03519B2D1");

        public string Format => "Apple 2IMG";

        public List<Partition> Partitions =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public List<Track> Tracks =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public List<Session> Sessions =>
            throw new FeatureUnsupportedImageException("Feature not supported by image format");

        public bool Identify(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);

            if(stream.Length < 65) return false;

            byte[] header = new byte[64];
            stream.Read(header, 0, 64);

            uint magic = BitConverter.ToUInt32(header, 0x00);
            if(magic != MAGIC) return false;

            uint dataoff = BitConverter.ToUInt32(header, 0x18);
            if(dataoff > stream.Length) return false;

            uint datasize = BitConverter.ToUInt32(header, 0x1C);
            // There seems to be incorrect endian in some images on the wild
            if(datasize           == 0x00800C00) datasize = 0x000C8000;
            if(dataoff + datasize > stream.Length) return false;

            uint commentoff = BitConverter.ToUInt32(header, 0x20);
            if(commentoff > stream.Length) return false;

            uint commentsize = BitConverter.ToUInt32(header, 0x24);
            if(commentoff + commentsize > stream.Length) return false;

            uint creatoroff = BitConverter.ToUInt32(header, 0x28);
            if(creatoroff > stream.Length) return false;

            uint creatorsize = BitConverter.ToUInt32(header, 0x2C);
            return creatoroff + creatorsize <= stream.Length;
        }

        public bool Open(IFilter imageFilter)
        {
            Stream stream = imageFilter.GetDataForkStream();
            stream.Seek(0, SeekOrigin.Begin);

            imageHeader = new A2ImgHeader();

            byte[] header = new byte[64];
            stream.Read(header, 0, 64);
            byte[] magic   = new byte[4];
            byte[] creator = new byte[4];

            Array.Copy(header, 0, magic,   0, 4);
            Array.Copy(header, 4, creator, 0, 4);

            imageHeader.Magic                 = BitConverter.ToUInt32(header, 0x00);
            imageHeader.Creator               = BitConverter.ToUInt32(header, 0x04);
            imageHeader.HeaderSize            = BitConverter.ToUInt16(header, 0x08);
            imageHeader.Version               = BitConverter.ToUInt16(header, 0x0A);
            imageHeader.ImageFormat           = (SectorOrder)BitConverter.ToUInt32(header, 0x0C);
            imageHeader.Flags                 = BitConverter.ToUInt32(header,              0x10);
            imageHeader.Blocks                = BitConverter.ToUInt32(header,              0x14);
            imageHeader.DataOffset            = BitConverter.ToUInt32(header,              0x18);
            imageHeader.DataSize              = BitConverter.ToUInt32(header,              0x1C);
            imageHeader.CommentOffset         = BitConverter.ToUInt32(header,              0x20);
            imageHeader.CommentSize           = BitConverter.ToUInt32(header,              0x24);
            imageHeader.CreatorSpecificOffset = BitConverter.ToUInt32(header,              0x28);
            imageHeader.CreatorSpecificSize   = BitConverter.ToUInt32(header,              0x2C);
            imageHeader.Reserved1             = BitConverter.ToUInt32(header,              0x30);
            imageHeader.Reserved2             = BitConverter.ToUInt32(header,              0x34);
            imageHeader.Reserved3             = BitConverter.ToUInt32(header,              0x38);
            imageHeader.Reserved4             = BitConverter.ToUInt32(header,              0x3C);

            if(imageHeader.DataSize == 0x00800C00)
            {
                imageHeader.DataSize = 0x000C8000;
                DicConsole.DebugWriteLine("2MG plugin", "Detected incorrect endian on data size field, correcting.");
            }

            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.magic = \"{0}\"",
                                      Encoding.ASCII.GetString(magic));
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.creator = \"{0}\"",
                                      Encoding.ASCII.GetString(creator));
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.headerSize = {0}",         imageHeader.HeaderSize);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.version = {0}",            imageHeader.Version);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.imageFormat = {0}",        imageHeader.ImageFormat);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.flags = 0x{0:X8}",         imageHeader.Flags);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.blocks = {0}",             imageHeader.Blocks);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.dataOffset = 0x{0:X8}",    imageHeader.DataOffset);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.dataSize = {0}",           imageHeader.DataSize);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.commentOffset = 0x{0:X8}", imageHeader.CommentOffset);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.commentSize = {0}",        imageHeader.CommentSize);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.creatorSpecificOffset = 0x{0:X8}",
                                      imageHeader.CreatorSpecificOffset);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.creatorSpecificSize = {0}",
                                      imageHeader.CreatorSpecificSize);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.reserved1 = 0x{0:X8}", imageHeader.Reserved1);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.reserved2 = 0x{0:X8}", imageHeader.Reserved2);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.reserved3 = 0x{0:X8}", imageHeader.Reserved3);
            DicConsole.DebugWriteLine("2MG plugin", "ImageHeader.reserved4 = 0x{0:X8}", imageHeader.Reserved4);

            if(imageHeader.DataSize    == 0 && imageHeader.Blocks == 0 &&
               imageHeader.ImageFormat != SectorOrder.ProDos) return false;

            byte[] tmp;
            int[]  offsets;

            switch(imageHeader.ImageFormat)
            {
                case SectorOrder.Nibbles:
                    tmp = new byte[imageHeader.DataSize];
                    stream.Seek(imageHeader.DataOffset, SeekOrigin.Begin);
                    stream.Read(tmp, 0, tmp.Length);
                    AppleNib    nibPlugin = new AppleNib();
                    ZZZNoFilter noFilter  = new ZZZNoFilter();
                    noFilter.Open(tmp);
                    nibPlugin.Open(noFilter);
                    decodedImage         = nibPlugin.ReadSectors(0, (uint)nibPlugin.Info.Sectors);
                    imageInfo.Sectors    = nibPlugin.Info.Sectors;
                    imageInfo.SectorSize = nibPlugin.Info.SectorSize;
                    break;
                case SectorOrder.Dos when imageHeader.DataSize    == 143360:
                case SectorOrder.ProDos when imageHeader.DataSize == 143360:
                    stream.Seek(imageHeader.DataOffset, SeekOrigin.Begin);
                    tmp = new byte[imageHeader.DataSize];
                    stream.Read(tmp, 0, tmp.Length);
                    bool isDos = tmp[0x11001] == 17 && tmp[0x11002] < 16 && tmp[0x11027] <= 122 && tmp[0x11034] == 35 &&
                                 tmp[0x11035] == 16 && tmp[0x11036] == 0 && tmp[0x11037] == 1;
                    decodedImage = new byte[imageHeader.DataSize];
                    offsets      = imageHeader.ImageFormat == SectorOrder.Dos
                                       ? (isDos ? deinterleave : interleave)
                                       : (isDos ? interleave : deinterleave);
                    for(int t = 0; t < 35; t++)
                    {
                        for(int s = 0; s < 16; s++)
                            Array.Copy(tmp, t * 16 * 256 + s * 256, decodedImage, t * 16 * 256 + offsets[s] * 256, 256);
                    }

                    imageInfo.Sectors    = 560;
                    imageInfo.SectorSize = 256;
                    break;
                case SectorOrder.Dos when imageHeader.DataSize == 819200:
                    stream.Seek(imageHeader.DataOffset, SeekOrigin.Begin);
                    tmp = new byte[imageHeader.DataSize];
                    stream.Read(tmp, 0, tmp.Length);
                    decodedImage = new byte[imageHeader.DataSize];
                    offsets      = interleave;
                    for(int t = 0; t < 200; t++)
                    {
                        for(int s = 0; s < 16; s++)
                            Array.Copy(tmp, t * 16 * 256 + s * 256, decodedImage, t * 16 * 256 + offsets[s] * 256, 256);
                    }

                    imageInfo.Sectors    = 1600;
                    imageInfo.SectorSize = 512;
                    break;
                default:
                    decodedImage         = null;
                    imageInfo.SectorSize = 512;
                    imageInfo.Sectors    = imageHeader.DataSize / 512;
                    break;
            }

            imageInfo.ImageSize = imageHeader.DataSize;

            switch(imageHeader.Creator)
            {
                case CREATOR_ASIMOV:
                    imageInfo.Application = "ASIMOV2";
                    break;
                case CREATOR_BERNIE:
                    imageInfo.Application = "Bernie ][ the Rescue";
                    break;
                case CREATOR_CATAKIG:
                    imageInfo.Application = "Catakig";
                    break;
                case CREATOR_SHEPPY:
                    imageInfo.Application = "Sheppy's ImageMaker";
                    break;
                case CREATOR_SWEET:
                    imageInfo.Application = "Sweet16";
                    break;
                case CREATOR_XGS:
                    imageInfo.Application = "XGS";
                    break;
                case CREATOR_CIDER:
                    imageInfo.Application = "CiderPress";
                    break;
                case CREATOR_DIC:
                    imageInfo.Application = "DiscImageChef";
                    break;
                default:
                    imageInfo.Application = $"Unknown creator code \"{Encoding.ASCII.GetString(creator)}\"";
                    break;
            }

            imageInfo.Version = imageHeader.Version.ToString();

            if(imageHeader.CommentOffset != 0 && imageHeader.CommentSize != 0)
            {
                stream.Seek(imageHeader.CommentOffset, SeekOrigin.Begin);

                byte[] comments = new byte[imageHeader.CommentSize];
                stream.Read(comments, 0, (int)imageHeader.CommentSize);
                imageInfo.Comments = Encoding.ASCII.GetString(comments);
            }

            imageInfo.CreationTime         = imageFilter.GetCreationTime();
            imageInfo.LastModificationTime = imageFilter.GetLastWriteTime();
            imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
            imageInfo.MediaType            = GetMediaType();

            a2MgImageFilter = imageFilter;

            imageInfo.XmlMediaType = XmlMediaType.BlockMedia;

            DicConsole.VerboseWriteLine("2MG image contains a disk of type {0}", imageInfo.MediaType);
            if(!string.IsNullOrEmpty(imageInfo.Comments))
                DicConsole.VerboseWriteLine("2MG comments: {0}", imageInfo.Comments);

            switch(imageInfo.MediaType)
            {
                case MediaType.Apple32SS:
                    imageInfo.Cylinders       = 35;
                    imageInfo.Heads           = 1;
                    imageInfo.SectorsPerTrack = 13;
                    break;
                case MediaType.Apple32DS:
                    imageInfo.Cylinders       = 35;
                    imageInfo.Heads           = 2;
                    imageInfo.SectorsPerTrack = 13;
                    break;
                case MediaType.Apple33SS:
                    imageInfo.Cylinders       = 35;
                    imageInfo.Heads           = 1;
                    imageInfo.SectorsPerTrack = 16;
                    break;
                case MediaType.Apple33DS:
                    imageInfo.Cylinders       = 35;
                    imageInfo.Heads           = 2;
                    imageInfo.SectorsPerTrack = 16;
                    break;
                case MediaType.AppleSonySS:
                    imageInfo.Cylinders = 80;
                    imageInfo.Heads     = 1;
                    // Variable sectors per track, this suffices
                    imageInfo.SectorsPerTrack = 10;
                    break;
                case MediaType.AppleSonyDS:
                    imageInfo.Cylinders = 80;
                    imageInfo.Heads     = 2;
                    // Variable sectors per track, this suffices
                    imageInfo.SectorsPerTrack = 10;
                    break;
                case MediaType.DOS_35_HD:
                    imageInfo.Cylinders       = 80;
                    imageInfo.Heads           = 2;
                    imageInfo.SectorsPerTrack = 18;
                    break;
            }

            return true;
        }

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

        public 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");

            byte[] buffer = new byte[length * imageInfo.SectorSize];

            if(decodedImage != null)
                Array.Copy(decodedImage, (long)(sectorAddress * imageInfo.SectorSize), buffer, 0,
                           length                             * imageInfo.SectorSize);
            else
            {
                Stream stream = a2MgImageFilter.GetDataForkStream();
                stream.Seek((long)(imageHeader.DataOffset + sectorAddress * imageInfo.SectorSize), SeekOrigin.Begin);
                stream.Read(buffer, 0, (int)(length                       * imageInfo.SectorSize));
            }

            return buffer;
        }

        public byte[] ReadDiskTag(MediaTagType tag)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

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

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

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

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

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

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

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

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

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

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

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

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

        public bool? VerifySector(ulong sectorAddress)
        {
            return null;
        }

        public bool? VerifySector(ulong sectorAddress, uint track)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public 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 = 0; i < imageInfo.Sectors; i++) unknownLbas.Add(i);

            return null;
        }

        public bool? VerifySectors(ulong sectorAddress, uint length, uint track, out List<ulong> failingLbas,
                                   out                                               List<ulong> unknownLbas)
        {
            throw new FeatureUnsupportedImageException("Feature not supported by image format");
        }

        public bool? VerifyMediaImage()
        {
            return null;
        }

        public IEnumerable<MediaTagType>  SupportedMediaTags  => new MediaTagType[] { };
        public IEnumerable<SectorTagType> SupportedSectorTags => new SectorTagType[] { };
        public IEnumerable<MediaType>     SupportedMediaTypes =>
            new[]
            {
                MediaType.Apple32SS, MediaType.Apple33SS, MediaType.AppleSonySS, MediaType.AppleSonyDS,
                MediaType.DOS_35_HD, MediaType.Unknown, MediaType.GENERIC_HDD
            };
        public IEnumerable<(string name, Type type, string description)> SupportedOptions =>
            new (string name, Type type, string description)[] { };
        public IEnumerable<string> KnownExtensions => new[] {".2mg"};
        public bool                IsWriting       { get; private set; }
        public string              ErrorMessage    { get; private set; }

        public bool Create(string path, MediaType mediaType, Dictionary<string, string> options, ulong sectors,
                           uint   sectorSize)
        {
            if(sectorSize     != 512)
                if(sectorSize != 256 || mediaType != MediaType.Apple32SS && mediaType != MediaType.Apple33SS)
                {
                    ErrorMessage = "Unsupported sector size";
                    return false;
                }

            if(!SupportedMediaTypes.Contains(mediaType))
            {
                ErrorMessage = $"Unsupport media format {mediaType}";
                return false;
            }

            if(sectors > uint.MaxValue)
            {
                ErrorMessage = "Too many sectors";
                return false;
            }

            imageInfo = new ImageInfo {MediaType = mediaType, SectorSize = sectorSize, Sectors = sectors};

            try { writingStream = new FileStream(path, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None); }
            catch(IOException e)
            {
                ErrorMessage = $"Could not create new image file, exception {e.Message}";
                return false;
            }

            IsWriting    = true;
            ErrorMessage = null;
            return true;
        }

        public bool WriteMediaTag(byte[] data, MediaTagType tag)
        {
            ErrorMessage = "Unsupported feature";
            return false;
        }

        public bool WriteSector(byte[] data, ulong sectorAddress)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";
                return false;
            }

            if(data.Length != imageInfo.SectorSize)
            {
                ErrorMessage = "Incorrect data size";
                return false;
            }

            if(sectorAddress >= imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";
                return false;
            }

            writingStream.Seek((long)(0x40 + sectorAddress * imageInfo.SectorSize), SeekOrigin.Begin);
            writingStream.Write(data, 0, data.Length);

            ErrorMessage = "";
            return true;
        }

        public bool WriteSectors(byte[] data, ulong sectorAddress, uint length)
        {
            if(!IsWriting)
            {
                ErrorMessage = "Tried to write on a non-writable image";
                return false;
            }

            if(data.Length % imageInfo.SectorSize != 0)
            {
                ErrorMessage = "Incorrect data size";
                return false;
            }

            if(sectorAddress + length > imageInfo.Sectors)
            {
                ErrorMessage = "Tried to write past image size";
                return false;
            }

            writingStream.Seek((long)(0x40 + sectorAddress * imageInfo.SectorSize), SeekOrigin.Begin);
            writingStream.Write(data, 0, data.Length);

            ErrorMessage = "";
            return true;
        }

        public bool WriteSectorLong(byte[] data, ulong sectorAddress)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        public bool WriteSectorsLong(byte[] data, ulong sectorAddress, uint length)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        public bool SetTracks(List<Track> tracks)
        {
            ErrorMessage = "Unsupported feature";
            return false;
        }

        public bool Close()
        {
            if(!IsWriting)
            {
                ErrorMessage = "Image is not opened for writing";
                return false;
            }

            writingStream.Seek(0x40 + 17 * 16 * 256, SeekOrigin.Begin);
            byte[] tmp = new byte[256];
            writingStream.Read(tmp, 0, tmp.Length);
            bool isDos = tmp[0x01] == 17 && tmp[0x02] < 16 && tmp[0x27] <= 122 && tmp[0x34] == 35 && tmp[0x35] == 16 &&
                         tmp[0x36] == 0  && tmp[0x37] == 1;

            imageHeader = new A2ImgHeader
            {
                Blocks     = (uint)(imageInfo.Sectors * imageInfo.SectorSize) / 512,
                Creator    = CREATOR_DIC,
                DataOffset = 0x40,
                DataSize   = (uint)(imageInfo.Sectors * imageInfo.SectorSize),
                Flags      =
                    (uint)(imageInfo.LastMediaSequence != 0
                               ? VALID_VOLUME_NUMBER + (imageInfo.MediaSequence & 0xFF)
                               : 0),
                HeaderSize  = 0x40,
                ImageFormat = isDos ? SectorOrder.Dos : SectorOrder.ProDos,
                Magic       = MAGIC,
                Version     = 1
            };

            if(!string.IsNullOrEmpty(imageInfo.Comments))
            {
                writingStream.Seek(0, SeekOrigin.End);
                tmp                       = Encoding.UTF8.GetBytes(imageInfo.Comments);
                imageHeader.CommentOffset = (uint)writingStream.Position;
                imageHeader.CommentSize   = (uint)(tmp.Length + 1);
                writingStream.Write(tmp, 0, tmp.Length);
                writingStream.WriteByte(0);
            }

            byte[] hdr    = new byte[Marshal.SizeOf(typeof(A2ImgHeader))];
            IntPtr hdrPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(A2ImgHeader)));
            Marshal.StructureToPtr(imageHeader, hdrPtr, true);
            Marshal.Copy(hdrPtr, hdr, 0, hdr.Length);
            Marshal.FreeHGlobal(hdrPtr);

            writingStream.Seek(0, SeekOrigin.Begin);
            writingStream.Write(hdr, 0, hdr.Length);

            writingStream.Flush();
            writingStream.Close();

            ErrorMessage = "";
            IsWriting    = false;

            return true;
        }

        public bool SetMetadata(ImageInfo metadata)
        {
            imageInfo.Comments          = metadata.Comments;
            imageInfo.LastMediaSequence = metadata.LastMediaSequence;
            imageInfo.MediaSequence     = metadata.MediaSequence;
            return true;
        }

        public bool SetGeometry(uint cylinders, uint heads, uint sectorsPerTrack)
        {
            // Geometry is not stored in image
            return true;
        }

        public bool WriteSectorTag(byte[] data, ulong sectorAddress, SectorTagType tag)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        public bool WriteSectorsTag(byte[] data, ulong sectorAddress, uint length, SectorTagType tag)
        {
            ErrorMessage = "Writing sectors with tags is not supported.";
            return false;
        }

        MediaType GetMediaType()
        {
            switch(imageInfo.Sectors)
            {
                case 455:  return MediaType.Apple32SS;
                case 910:  return MediaType.Apple32DS;
                case 560:  return MediaType.Apple33SS;
                case 1120: return MediaType.Apple33DS;
                case 800:  return MediaType.AppleSonySS;
                case 1600: return MediaType.AppleSonyDS;
                case 2880: return MediaType.DOS_35_HD;
                default:   return MediaType.Unknown;
            }
        }

        enum SectorOrder : uint
        {
            Dos     = 0,
            ProDos  = 1,
            Nibbles = 2
        }

        [SuppressMessage("ReSharper", "NotAccessedField.Local")]
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        struct A2ImgHeader
        {
            /// <summary>
            ///     Offset 0x00, magic
            /// </summary>
            public uint Magic;
            /// <summary>
            ///     Offset 0x04, disk image creator ID
            /// </summary>
            public uint Creator;
            /// <summary>
            ///     Offset 0x08, header size, constant 0x0040
            /// </summary>
            public ushort HeaderSize;
            /// <summary>
            ///     Offset 0x0A, disk image version
            /// </summary>
            public ushort Version;
            /// <summary>
            ///     Offset 0x0C, disk image format
            /// </summary>
            public SectorOrder ImageFormat;
            /// <summary>
            ///     Offset 0x10, flags and volume number
            /// </summary>
            public uint Flags;
            /// <summary>
            ///     Offset 0x14, blocks for ProDOS, 0 otherwise
            /// </summary>
            public uint Blocks;
            /// <summary>
            ///     Offset 0x18, offset to data
            /// </summary>
            public uint DataOffset;
            /// <summary>
            ///     Offset 0x1C, data size in bytes
            /// </summary>
            public uint DataSize;
            /// <summary>
            ///     Offset 0x20, offset to optional comment
            /// </summary>
            public uint CommentOffset;
            /// <summary>
            ///     Offset 0x24, length of optional comment
            /// </summary>
            public uint CommentSize;
            /// <summary>
            ///     Offset 0x28, offset to creator specific chunk
            /// </summary>
            public uint CreatorSpecificOffset;
            /// <summary>
            ///     Offset 0x2C, creator specific chunk size
            /// </summary>
            public uint CreatorSpecificSize;
            /// <summary>
            ///     Offset 0x30, reserved, should be zero
            /// </summary>
            public uint Reserved1;
            /// <summary>
            ///     Offset 0x34, reserved, should be zero
            /// </summary>
            public uint Reserved2;
            /// <summary>
            ///     Offset 0x38, reserved, should be zero
            /// </summary>
            public uint Reserved3;
            /// <summary>
            ///     Offset 0x3C, reserved, should be zero
            /// </summary>
            public uint Reserved4;
        }
    }
}