Aaru/Aaru.Images/AppleDOS/Read.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Read.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Reads interleaved Apple ][ 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;
using System.IO;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;

namespace Aaru.Images;

public sealed partial class AppleDos
{
#region IWritableImage Members

    /// <inheritdoc />
    public ErrorNumber Open(IFilter imageFilter)
    {
        Stream stream = imageFilter.GetDataForkStream();
        stream.Seek(0, SeekOrigin.Begin);

        var tmp = new byte[imageFilter.DataForkLength];
        stream.EnsureRead(tmp, 0, tmp.Length);

        _extension = Path.GetExtension(imageFilter.Filename)?.ToLower();

        if(_extension is ".d13" or ".do" && tmp.Length == 116480)
        {
            _dos32         = true;
            _deinterleaved = tmp;
        }
        else
        {
            bool isDos = tmp[0x11001] == 17  &&
                         tmp[0x11002] < 16   &&
                         tmp[0x11027] <= 122 &&
                         tmp[0x11034] == 35  &&
                         tmp[0x11035] == 16  &&
                         tmp[0x11036] == 0   &&
                         tmp[0x11037] == 1;

            _deinterleaved = new byte[tmp.Length];

            int[] offsets = _extension == ".do"
                                ? isDos ? _deinterleave : _interleave
                                : isDos
                                    ? _interleave
                                    : _deinterleave;

            for(var t = 0; t < 35; t++)
            {
                for(var s = 0; s < 16; s++)
                    Array.Copy(tmp, t * 16 * 256 + s * 256, _deinterleaved, t * 16 * 256 + offsets[s] * 256, 256);
            }
        }

        _imageInfo.SectorSize           = 256;
        _imageInfo.ImageSize            = (ulong)imageFilter.DataForkLength;
        _imageInfo.CreationTime         = imageFilter.CreationTime;
        _imageInfo.LastModificationTime = imageFilter.LastWriteTime;
        _imageInfo.MediaTitle           = Path.GetFileNameWithoutExtension(imageFilter.Filename);
        _imageInfo.Sectors              = _dos32 ? 455u : 560u;
        _imageInfo.MediaType            = _dos32 ? MediaType.Apple32SS : MediaType.Apple33SS;
        _imageInfo.MetadataMediaType    = MetadataMediaType.BlockMedia;
        _imageInfo.Cylinders            = 35;
        _imageInfo.Heads                = 1;
        _imageInfo.SectorsPerTrack      = _dos32 ? 13u : 16u;

        return ErrorNumber.NoError;
    }

    /// <inheritdoc />
    public ErrorNumber ReadSector(ulong sectorAddress, bool negative, out byte[] buffer, out SectorStatus sectorStatus)
    {
        sectorStatus = SectorStatus.Dumped;

        return ReadSectors(sectorAddress, false, 1, out buffer, out _);
    }

    /// <inheritdoc />
    public ErrorNumber ReadSectors(ulong              sectorAddress, bool negative, uint length, out byte[] buffer,
                                   out SectorStatus[] sectorStatus)
    {
        buffer       = null;
        sectorStatus = null;

        if(negative) return ErrorNumber.NotSupported;

        if(sectorAddress > _imageInfo.Sectors - 1) return ErrorNumber.OutOfRange;

        if(sectorAddress + length > _imageInfo.Sectors) return ErrorNumber.OutOfRange;

        sectorStatus = new SectorStatus[length];
        for(uint i = 0; i < length; i++) sectorStatus[i] = SectorStatus.Dumped;

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

        Array.Copy(_deinterleaved, (int)(sectorAddress * _imageInfo.SectorSize), buffer, 0, buffer.Length);

        return ErrorNumber.NoError;
    }

#endregion
}