Aaru/Aaru.Filters/MacBinary.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : MacBinary.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Filters.
//
// --[ Description ] ----------------------------------------------------------
//
//     Provides a filter to open MacBinary files.
//
// --[ 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 © 2011-2023 Natalia Portillo
// ****************************************************************************/

using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;
using Marshal = Aaru.Helpers.Marshal;

namespace Aaru.Filters;

// TODO: Interpret fdScript
/// <inheritdoc />
/// <summary>Decodes MacBinary files</summary>
public sealed class MacBinary : IFilter
{
    const uint MAGIC = 0x6D42494E;
    byte[]     _bytes;
    long       _dataForkOff;
    Header     _header;
    bool       _isBytes, _isStream, _isPath;
    long       _rsrcForkOff;
    Stream     _stream;

    /// <inheritdoc />
    public string Name => Localization.MacBinary_Name;
    /// <inheritdoc />
    public Guid Id => new("D7C321D3-E51F-45DF-A150-F6BFDF0D7704");
    /// <inheritdoc />
    public string Author => Authors.NataliaPortillo;

    /// <inheritdoc />
    public void Close()
    {
        _bytes = null;
        _stream?.Close();
        _isBytes  = false;
        _isStream = false;
        _isPath   = false;
    }

    /// <inheritdoc />
    public string BasePath { get; private set; }

    /// <inheritdoc />
    public DateTime CreationTime { get; private set; }

    /// <inheritdoc />
    public long DataForkLength => _header.dataLength;

    /// <inheritdoc />
    public Stream GetDataForkStream()
    {
        if(_header.dataLength == 0)
            return null;

        if(_isBytes)
            return new OffsetStream(_bytes, _dataForkOff, _dataForkOff + _header.dataLength - 1);

        if(_isStream)
            return new OffsetStream(_stream, _dataForkOff, _dataForkOff + _header.dataLength - 1);

        if(_isPath)
            return new OffsetStream(BasePath, FileMode.Open, FileAccess.Read, _dataForkOff,
                                    _dataForkOff + _header.dataLength - 1);

        return null;
    }

    /// <inheritdoc />
    public string Filename { get; private set; }

    /// <inheritdoc />
    public DateTime LastWriteTime { get; private set; }

    /// <inheritdoc />
    public long Length => _header.dataLength + _header.resourceLength;

    /// <inheritdoc />
    public string ParentFolder => System.IO.Path.GetDirectoryName(BasePath);

    /// <inheritdoc />
    public string Path => BasePath;

    /// <inheritdoc />
    public long ResourceForkLength => _header.resourceLength;

    /// <inheritdoc />
    public Stream GetResourceForkStream()
    {
        if(_header.resourceLength == 0)
            return null;

        if(_isBytes)
            return new OffsetStream(_bytes, _rsrcForkOff, _rsrcForkOff + _header.resourceLength - 1);

        if(_isStream)
            return new OffsetStream(_stream, _rsrcForkOff, _rsrcForkOff + _header.resourceLength - 1);

        if(_isPath)
            return new OffsetStream(BasePath, FileMode.Open, FileAccess.Read, _rsrcForkOff,
                                    _rsrcForkOff + _header.resourceLength - 1);

        return null;
    }

    /// <inheritdoc />
    public bool HasResourceFork => _header.resourceLength > 0;

    /// <inheritdoc />
    public bool Identify(byte[] buffer)
    {
        if(buffer        == null ||
           buffer.Length < 128)
            return false;

        byte[] hdrB = new byte[128];
        Array.Copy(buffer, 0, hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        return _header.magic == MAGIC || (_header.version == 0 && _header.filename[0] > 0 && _header.filename[0] < 64 &&
                                          _header.zero1   == 0 && _header is { zero2: 0, reserved: 0 } &&
                                          (_header.dataLength > 0 || _header.resourceLength > 0));
    }

    /// <inheritdoc />
    public bool Identify(Stream stream)
    {
        if(stream        == null ||
           stream.Length < 128)
            return false;

        byte[] hdrB = new byte[128];
        stream.Seek(0, SeekOrigin.Begin);
        stream.EnsureRead(hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        return _header.magic == MAGIC || (_header.version == 0 && _header.filename[0] > 0 && _header.filename[0] < 64 &&
                                          _header.zero1   == 0 && _header is { zero2: 0, reserved: 0 } &&
                                          (_header.dataLength > 0 || _header.resourceLength > 0));
    }

    /// <inheritdoc />
    public bool Identify(string path)
    {
        if(!File.Exists(path))
            return false;

        var fstream = new FileStream(path, FileMode.Open, FileAccess.Read);

        if(fstream.Length < 128)
            return false;

        byte[] hdrB = new byte[128];
        fstream.EnsureRead(hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        fstream.Close();

        return _header.magic == MAGIC || (_header.version == 0 && _header.filename[0] > 0 && _header.filename[0] < 64 &&
                                          _header.zero1   == 0 && _header is { zero2: 0, reserved: 0 } &&
                                          (_header.dataLength > 0 || _header.resourceLength > 0));
    }

    /// <inheritdoc />
    public ErrorNumber Open(byte[] buffer)
    {
        var ms = new MemoryStream(buffer);
        ms.Seek(0, SeekOrigin.Begin);

        byte[] hdrB = new byte[128];
        ms.EnsureRead(hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        uint blocks = 1;
        blocks += (uint)(_header.secondaryHeaderLength / 128);

        if(_header.secondaryHeaderLength % 128 > 0)
            blocks++;

        _dataForkOff =  blocks             * 128;
        blocks       += _header.dataLength / 128;

        if(_header.dataLength % 128 > 0)
            blocks++;

        _rsrcForkOff = blocks * 128;

        Filename      = StringHandlers.PascalToString(_header.filename, Encoding.GetEncoding("macintosh"));
        CreationTime  = DateHandlers.MacToDateTime(_header.creationTime);
        LastWriteTime = DateHandlers.MacToDateTime(_header.modificationTime);

        ms.Close();
        _isBytes = true;
        _bytes   = buffer;

        return ErrorNumber.NoError;
    }

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

        byte[] hdrB = new byte[128];
        stream.EnsureRead(hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        uint blocks = 1;
        blocks += (uint)(_header.secondaryHeaderLength / 128);

        if(_header.secondaryHeaderLength % 128 > 0)
            blocks++;

        _dataForkOff =  blocks             * 128;
        blocks       += _header.dataLength / 128;

        if(_header.dataLength % 128 > 0)
            blocks++;

        _rsrcForkOff = blocks * 128;

        Filename      = StringHandlers.PascalToString(_header.filename, Encoding.GetEncoding("macintosh"));
        CreationTime  = DateHandlers.MacToDateTime(_header.creationTime);
        LastWriteTime = DateHandlers.MacToDateTime(_header.modificationTime);

        stream.Seek(0, SeekOrigin.Begin);
        _isStream = true;
        _stream   = stream;

        return ErrorNumber.NoError;
    }

    /// <inheritdoc />
    public ErrorNumber Open(string path)
    {
        var fs = new FileStream(path, FileMode.Open, FileAccess.Read);
        fs.Seek(0, SeekOrigin.Begin);

        byte[] hdrB = new byte[128];
        fs.EnsureRead(hdrB, 0, 128);
        _header = Marshal.ByteArrayToStructureBigEndian<Header>(hdrB);

        uint blocks = 1;
        blocks += (uint)(_header.secondaryHeaderLength / 128);

        if(_header.secondaryHeaderLength % 128 > 0)
            blocks++;

        _dataForkOff =  blocks             * 128;
        blocks       += _header.dataLength / 128;

        if(_header.dataLength % 128 > 0)
            blocks++;

        _rsrcForkOff = blocks * 128;

        Filename      = StringHandlers.PascalToString(_header.filename, Encoding.GetEncoding("macintosh"));
        CreationTime  = DateHandlers.MacToDateTime(_header.creationTime);
        LastWriteTime = DateHandlers.MacToDateTime(_header.modificationTime);

        fs.Close();
        _isPath  = true;
        BasePath = path;

        return ErrorNumber.NoError;
    }

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    struct Header
    {
        /// <summary>0x00, MacBinary version, 0</summary>
        public readonly byte version;
        /// <summary>0x01, Str63 Pascal filename</summary>
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 64)]
        public readonly byte[] filename;
        /// <summary>0x41, File type</summary>
        public readonly uint type;
        /// <summary>0x45, File creator</summary>
        public readonly uint creator;
        /// <summary>0x49, High byte of Finder flags</summary>
        public readonly byte finderFlags;
        /// <summary>0x4A, Must be 0</summary>
        public readonly byte zero1;
        /// <summary>0x4B, File's icon vertical position within its window</summary>
        public readonly ushort verticalPosition;
        /// <summary>0x4D, File's icon horizontal position within its window</summary>
        public readonly ushort horizontalPosition;
        /// <summary>0x4F, File's window or folder ID</summary>
        public readonly short windowID;
        /// <summary>0x51, Protected flag</summary>
        public readonly byte protect;
        /// <summary>0x52, Must be 0</summary>
        public readonly byte zero2;
        /// <summary>0x53, Size of data fork</summary>
        public readonly uint dataLength;
        /// <summary>0x57, Size of resource fork</summary>
        public readonly uint resourceLength;
        /// <summary>0x5B, File's creation time</summary>
        public readonly uint creationTime;
        /// <summary>0x5F, File's last modified time</summary>
        public readonly uint modificationTime;
        /// <summary>0x63, Length of Get Info comment</summary>
        public readonly ushort commentLength;
        /// <summary>0x65, Low byte of Finder flags</summary>
        public readonly byte finderFlags2;

        #region MacBinary III
        /// <summary>0x66, magic identifier, "mBIN"</summary>
        public readonly uint magic;
        /// <summary>0x6A, fdScript from fxInfo, identifies codepage of filename</summary>
        public readonly byte fdScript;
        /// <summary>0x6B, fdXFlags from fxInfo, extended Mac OS 8 finder flags</summary>
        public readonly byte fdXFlags;
        #endregion MacBinary III

        /// <summary>0x6C, unused</summary>
        public readonly ulong reserved;
        /// <summary>0x74, Total unpacked files</summary>
        public readonly uint totalPackedFiles;

        #region MacBinary II
        /// <summary>0x78, Length of secondary header</summary>
        public readonly ushort secondaryHeaderLength;
        /// <summary>0x7A, version number of MacBinary that wrote this file, starts at 129</summary>
        public readonly byte version2;
        /// <summary>0x7B, version number of MacBinary required to open this file, starts at 129</summary>
        public readonly byte minVersion;
        /// <summary>0x7C, CRC of previous bytes</summary>
        public readonly short crc;
        #endregion MacBinary II

        /// <summary>0x7E, Reserved for computer type and OS ID</summary>
        public readonly short computerID;
    }
}