Aaru/Aaru.Images/DiskCopy42/Identify.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Identify.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies Apple DiskCopy 4.2 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.Interfaces;
using Aaru.Helpers;
using Aaru.Logging;
using Claunia.Encoding;

namespace Aaru.Images;

public sealed partial class DiskCopy42
{
#region IWritableImage Members

    /// <inheritdoc />
    public bool Identify(IFilter imageFilter)
    {
        Stream stream = imageFilter.GetDataForkStream();
        stream.Seek(0, SeekOrigin.Begin);
        var buffer  = new byte[0x58];
        var pString = new byte[64];
        stream.EnsureRead(buffer, 0, 0x58);

        // Incorrect pascal string length, not DC42
        if(buffer[0] > 63) return false;

        var tmpHeader = new Header();

        Array.Copy(buffer, 0, pString, 0, 64);

        tmpHeader.DiskName     = StringHandlers.PascalToString(pString, Encoding.GetEncoding("macintosh"));
        tmpHeader.DataSize     = BigEndianBitConverter.ToUInt32(buffer, 0x40);
        tmpHeader.TagSize      = BigEndianBitConverter.ToUInt32(buffer, 0x44);
        tmpHeader.DataChecksum = BigEndianBitConverter.ToUInt32(buffer, 0x48);
        tmpHeader.TagChecksum  = BigEndianBitConverter.ToUInt32(buffer, 0x4C);
        tmpHeader.Format       = buffer[0x50];
        tmpHeader.FmtByte      = buffer[0x51];
        tmpHeader.Valid        = buffer[0x52];
        tmpHeader.Reserved     = buffer[0x53];

        AaruLogging.Debug(MODULE_NAME, "tmp_header.diskName = \"{0}\"",      tmpHeader.DiskName);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.dataSize = {0} bytes",    tmpHeader.DataSize);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.tagSize = {0} bytes",     tmpHeader.TagSize);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.dataChecksum = 0x{0:X8}", tmpHeader.DataChecksum);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.tagChecksum = 0x{0:X8}",  tmpHeader.TagChecksum);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.format = 0x{0:X2}",       tmpHeader.Format);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.fmtByte = 0x{0:X2}",      tmpHeader.FmtByte);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.valid = {0}",             tmpHeader.Valid);
        AaruLogging.Debug(MODULE_NAME, "tmp_header.reserved = {0}",          tmpHeader.Reserved);

        if(tmpHeader.Valid != 1 || tmpHeader.Reserved != 0) return false;

        // Some versions seem to incorrectly create little endian fields
        if(tmpHeader.DataSize + tmpHeader.TagSize + 0x54 != imageFilter.DataForkLength &&
           tmpHeader.Format                              != kSigmaFormatTwiggy)
        {
            tmpHeader.DataSize     = BitConverter.ToUInt32(buffer, 0x40);
            tmpHeader.TagSize      = BitConverter.ToUInt32(buffer, 0x44);
            tmpHeader.DataChecksum = BitConverter.ToUInt32(buffer, 0x48);
            tmpHeader.TagChecksum  = BitConverter.ToUInt32(buffer, 0x4C);

            if(tmpHeader.DataSize + tmpHeader.TagSize + 0x54 != imageFilter.DataForkLength &&
               tmpHeader.Format                              != kSigmaFormatTwiggy)
                return false;
        }

        if(tmpHeader.Format != kSonyFormat400K    &&
           tmpHeader.Format != kSonyFormat800K    &&
           tmpHeader.Format != kSonyFormat720K    &&
           tmpHeader.Format != kSonyFormat1440K   &&
           tmpHeader.Format != kSonyFormat1680K   &&
           tmpHeader.Format != kSigmaFormatTwiggy &&
           tmpHeader.Format != kNotStandardFormat)
        {
            AaruLogging.Debug(MODULE_NAME, Localization.Unknown_tmp_header_format_equals_0_value, tmpHeader.Format);

            return false;
        }

        if(tmpHeader.FmtByte != kSonyFmtByte400K          &&
           tmpHeader.FmtByte != kSonyFmtByte800K          &&
           tmpHeader.FmtByte != kSonyFmtByte800KIncorrect &&
           tmpHeader.FmtByte != kSonyFmtByteProDos        &&
           tmpHeader.FmtByte != kInvalidFmtByte           &&
           tmpHeader.FmtByte != kSigmaFmtByteTwiggy       &&
           tmpHeader.FmtByte != kFmtNotStandard           &&
           tmpHeader.FmtByte != kMacOSXFmtByte)
        {
            AaruLogging.Debug(MODULE_NAME, Localization.Unknown_tmp_header_fmtByte_equals_0_value, tmpHeader.FmtByte);

            return false;
        }

        if(tmpHeader.FmtByte != kInvalidFmtByte) return true;

        AaruLogging.Debug(MODULE_NAME, Localization.Image_says_its_unformatted);

        return false;
    }

#endregion
}