Aaru/Aaru.Images/MaxiDisk/Identify.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Identify.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies MaxiDisk 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 © 2011-2025 Natalia Portillo
// ****************************************************************************/

using System.IO;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;
using Aaru.Logging;

namespace Aaru.Images;

public sealed partial class MaxiDisk
{
#region IWritableImage Members

    /// <inheritdoc />
    public bool Identify(IFilter imageFilter)
    {
        Stream stream = imageFilter.GetDataForkStream();

        if(stream.Length < 8) return false;

        var buffer = new byte[8];
        stream.Seek(0, SeekOrigin.Begin);
        stream.EnsureRead(buffer, 0, buffer.Length);

        Header tmpHeader = Marshal.ByteArrayToStructureLittleEndian<Header>(buffer);

        AaruLogging.Debug(MODULE_NAME, "tmp_header.unknown = {0}",        tmpHeader.unknown);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.diskType = {0}",       tmpHeader.diskType);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.heads = {0}",          tmpHeader.heads);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.cylinders = {0}",      tmpHeader.cylinders);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.bytesPerSector = {0}", tmpHeader.bytesPerSector);

        AaruLogging.Debug(MODULE_NAME, "tmp_header.sectorsPerTrack = {0}", tmpHeader.sectorsPerTrack);

        AaruLogging.Debug(MODULE_NAME, "tmp_header.unknown2 = {0}", tmpHeader.unknown2);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.unknown3 = {0}", tmpHeader.unknown3);

        // This is hardcoded
        // But its possible values are unknown...
        //if(tmp_header.diskType > 11)
        //    return false;

        // Only floppies supported
        if(tmpHeader.heads is 0 or > 2) return false;

        // No floppies with more than this?
        if(tmpHeader.cylinders > 90) return false;

        // Maximum supported bps is 16384
        if(tmpHeader.bytesPerSector > 7) return false;

        int expectedFileSize = tmpHeader.heads           *
                               tmpHeader.cylinders       *
                               tmpHeader.sectorsPerTrack *
                               (128 << tmpHeader.bytesPerSector) +
                               8;

        return expectedFileSize == stream.Length;
    }

#endregion
}