Aaru/Aaru.Filesystems/ISO9660/Dir.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Dir.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : ISO9660 filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Handles directory traversal and listing.
//
// --[ 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 © 2011-2021 Natalia Portillo
// In the loving memory of Facunda "Tata" Suárez Domínguez, R.I.P. 2019/07/24
// ****************************************************************************/

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using Aaru.CommonTypes.Structs;
using Aaru.Helpers;

namespace Aaru.Filesystems
{
    public sealed partial class ISO9660
    {
        Dictionary<string, Dictionary<string, DecodedDirectoryEntry>> _directoryCache;

        public Errno ReadDir(string path, out List<string> contents)
        {
            contents = null;

            if(!_mounted)
                return Errno.AccessDenied;

            if(string.IsNullOrWhiteSpace(path) ||
               path == "/")
            {
                contents = GetFilenames(_rootDirectoryCache);

                return Errno.NoError;
            }

            string cutPath = path.StartsWith("/", StringComparison.Ordinal)
                                 ? path.Substring(1).ToLower(CultureInfo.CurrentUICulture)
                                 : path.ToLower(CultureInfo.CurrentUICulture);

            if(_directoryCache.TryGetValue(cutPath, out Dictionary<string, DecodedDirectoryEntry> currentDirectory))
            {
                contents = currentDirectory.Keys.ToList();

                return Errno.NoError;
            }

            string[] pieces = cutPath.Split(new[]
            {
                '/'
            }, StringSplitOptions.RemoveEmptyEntries);

            KeyValuePair<string, DecodedDirectoryEntry> entry =
                _rootDirectoryCache.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[0]);

            if(string.IsNullOrEmpty(entry.Key))
                return Errno.NoSuchFile;

            if(!entry.Value.Flags.HasFlag(FileFlags.Directory))
                return Errno.NotDirectory;

            string currentPath = pieces[0];

            currentDirectory = _rootDirectoryCache;

            for(int p = 0; p < pieces.Length; p++)
            {
                entry = currentDirectory.FirstOrDefault(t => t.Key.ToLower(CultureInfo.CurrentUICulture) == pieces[p]);

                if(string.IsNullOrEmpty(entry.Key))
                    return Errno.NoSuchFile;

                if(!entry.Value.Flags.HasFlag(FileFlags.Directory))
                    return Errno.NotDirectory;

                currentPath = p == 0 ? pieces[0] : $"{currentPath}/{pieces[p]}";

                if(_directoryCache.TryGetValue(currentPath, out currentDirectory))
                    continue;

                if(entry.Value.Extents.Count == 0)
                    return Errno.InvalidArgument;

                currentDirectory = _cdi
                                       ? DecodeCdiDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
                                                            entry.Value.Extents[0].size)
                                       : _highSierra
                                           ? DecodeHighSierraDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
                                                                       entry.Value.Extents[0].size)
                                           : DecodeIsoDirectory(entry.Value.Extents[0].extent + entry.Value.XattrLength,
                                                                entry.Value.Extents[0].size);

                if(_usePathTable)
                    foreach(DecodedDirectoryEntry subDirectory in _cdi
                                                                      ? GetSubdirsFromCdiPathTable(currentPath)
                                                                      : _highSierra
                                                                          ? GetSubdirsFromHighSierraPathTable(currentPath)
                                                                          : GetSubdirsFromIsoPathTable(currentPath))
                        currentDirectory[subDirectory.Filename] = subDirectory;

                _directoryCache.Add(currentPath, currentDirectory);
            }

            contents = GetFilenames(currentDirectory);

            return Errno.NoError;
        }

        List<string> GetFilenames(Dictionary<string, DecodedDirectoryEntry> dirents)
        {
            List<string> contents = new List<string>();

            foreach(DecodedDirectoryEntry entry in dirents.Values)
                switch(_namespace)
                {
                    case Namespace.Normal:
                        contents.Add(entry.Filename.EndsWith(";1", StringComparison.Ordinal)
                                         ? entry.Filename.Substring(0, entry.Filename.Length - 2) : entry.Filename);

                        break;
                    case Namespace.Vms:
                    case Namespace.Joliet:
                    case Namespace.Rrip:
                    case Namespace.Romeo:
                        contents.Add(entry.Filename);

                        break;
                    default: throw new ArgumentOutOfRangeException();
                }

            return contents;
        }

        Dictionary<string, DecodedDirectoryEntry> DecodeCdiDirectory(ulong start, uint size)
        {
            Dictionary<string, DecodedDirectoryEntry> entries  = new Dictionary<string, DecodedDirectoryEntry>();
            int                                       entryOff = 0;

            byte[] data = ReadSingleExtent(size, (uint)start);

            while(entryOff + _cdiDirectoryRecordSize < data.Length)
            {
                CdiDirectoryRecord record =
                    Marshal.ByteArrayToStructureBigEndian<CdiDirectoryRecord>(data, entryOff, _cdiDirectoryRecordSize);

                if(record.length == 0)
                    break;

                // Special entries for current and parent directories, skip them
                if(record.name_len == 1)
                    if(data[entryOff + _directoryRecordSize] == 0 ||
                       data[entryOff + _directoryRecordSize] == 1)
                    {
                        entryOff += record.length;

                        continue;
                    }

                var entry = new DecodedDirectoryEntry
                {
                    Size                 = record.size,
                    Filename             = Encoding.GetString(data, entryOff + _directoryRecordSize, record.name_len),
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Timestamp            = DecodeHighSierraDateTime(record.date),
                    XattrLength          = record.xattr_len
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.start_lbn, record.size)
                    };

                if(record.flags.HasFlag(CdiFileFlags.Hidden))
                {
                    entry.Flags |= FileFlags.Hidden;

                    continue;
                }

                int systemAreaStart = entryOff + record.name_len + _cdiDirectoryRecordSize;

                if(systemAreaStart % 2 != 0)
                    systemAreaStart++;

                entry.CdiSystemArea =
                    Marshal.ByteArrayToStructureBigEndian<CdiSystemArea>(data, systemAreaStart, _cdiSystemAreaSize);

                if(entry.CdiSystemArea.Value.attributes.HasFlag(CdiAttributes.Directory))
                    entry.Flags |= FileFlags.Directory;

                if(!entry.CdiSystemArea.Value.attributes.HasFlag(CdiAttributes.Directory) ||
                   !_usePathTable)
                    entries[entry.Filename] = entry;

                entryOff += record.length;
            }

            return entries;
        }

        Dictionary<string, DecodedDirectoryEntry> DecodeHighSierraDirectory(ulong start, uint size)
        {
            Dictionary<string, DecodedDirectoryEntry> entries  = new Dictionary<string, DecodedDirectoryEntry>();
            int                                       entryOff = 0;

            byte[] data = ReadSingleExtent(size, (uint)start);

            while(entryOff + _directoryRecordSize < data.Length)
            {
                HighSierraDirectoryRecord record =
                    Marshal.ByteArrayToStructureLittleEndian<HighSierraDirectoryRecord>(data, entryOff,
                        _highSierraDirectoryRecordSize);

                if(record.length == 0)
                    break;

                // Special entries for current and parent directories, skip them
                if(record.name_len == 1)
                    if(data[entryOff + _directoryRecordSize] == 0 ||
                       data[entryOff + _directoryRecordSize] == 1)
                    {
                        entryOff += record.length;

                        continue;
                    }

                var entry = new DecodedDirectoryEntry
                {
                    Size                 = record.size,
                    Flags                = record.flags,
                    Interleave           = record.interleave,
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Filename             = Encoding.GetString(data, entryOff + _directoryRecordSize, record.name_len),
                    Timestamp            = DecodeHighSierraDateTime(record.date),
                    XattrLength          = record.xattr_len
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.extent, record.size)
                    };

                if(entry.Flags.HasFlag(FileFlags.Directory) && _usePathTable)
                {
                    entryOff += record.length;

                    continue;
                }

                if(!entries.ContainsKey(entry.Filename))
                    entries.Add(entry.Filename, entry);

                entryOff += record.length;
            }

            if(_useTransTbl)
                DecodeTransTable(entries);

            return entries;
        }

        Dictionary<string, DecodedDirectoryEntry> DecodeIsoDirectory(ulong start, uint size)
        {
            Dictionary<string, DecodedDirectoryEntry> entries  = new Dictionary<string, DecodedDirectoryEntry>();
            int                                       entryOff = 0;

            byte[] data = ReadSingleExtent(size, (uint)start);

            while(entryOff + _directoryRecordSize < data.Length)
            {
                DirectoryRecord record =
                    Marshal.ByteArrayToStructureLittleEndian<DirectoryRecord>(data, entryOff, _directoryRecordSize);

                if(record.length == 0)
                    break;

                // Special entries for current and parent directories, skip them
                if(record.name_len == 1)
                    if(data[entryOff + _directoryRecordSize] == 0 ||
                       data[entryOff + _directoryRecordSize] == 1)
                    {
                        entryOff += record.length;

                        continue;
                    }

                var entry = new DecodedDirectoryEntry
                {
                    Size  = record.size,
                    Flags = record.flags,
                    Filename =
                        _joliet ? Encoding.BigEndianUnicode.GetString(data, entryOff + _directoryRecordSize,
                                                                      record.name_len)
                            : Encoding.GetString(data, entryOff + _directoryRecordSize, record.name_len),
                    FileUnitSize         = record.file_unit_size,
                    Interleave           = record.interleave,
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Timestamp            = DecodeIsoDateTime(record.date),
                    XattrLength          = record.xattr_len
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.extent, record.size)
                    };

                if(entry.Flags.HasFlag(FileFlags.Directory) && _usePathTable)
                {
                    entryOff += record.length;

                    continue;
                }

                // Mac OS can use slashes, we cannot
                entry.Filename = entry.Filename.Replace('/', '\u2215');

                // Tailing '.' is only allowed on RRIP. If present it will be recreated below with the alternate name
                if(entry.Filename.EndsWith(".", StringComparison.Ordinal))
                    entry.Filename = entry.Filename.Substring(0, entry.Filename.Length - 1);

                if(entry.Filename.EndsWith(".;1", StringComparison.Ordinal))
                    entry.Filename = entry.Filename.Substring(0, entry.Filename.Length - 3) + ";1";

                // This is a legal Joliet name, different from VMS version fields, but Nero MAX incorrectly creates these filenames
                if(_joliet && entry.Filename.EndsWith(";1", StringComparison.Ordinal))
                    entry.Filename = entry.Filename.Substring(0, entry.Filename.Length - 2);

                int systemAreaStart  = entryOff      + record.name_len + _directoryRecordSize;
                int systemAreaLength = record.length - record.name_len - _directoryRecordSize;

                if(systemAreaStart % 2 != 0)
                {
                    systemAreaStart++;
                    systemAreaLength--;
                }

                DecodeSystemArea(data, systemAreaStart, systemAreaStart + systemAreaLength, ref entry,
                                 out bool hasResourceFork);

                if(entry.Flags.HasFlag(FileFlags.Associated))
                {
                    if(entries.ContainsKey(entry.Filename))
                    {
                        if(hasResourceFork)
                        {
                            entries[entry.Filename].ResourceFork.Size += entry.Size;
                            entries[entry.Filename].ResourceFork.Extents.Add(entry.Extents[0]);
                        }
                        else
                        {
                            entries[entry.Filename].AssociatedFile.Size += entry.Size;
                            entries[entry.Filename].AssociatedFile.Extents.Add(entry.Extents[0]);
                        }
                    }
                    else
                    {
                        entries[entry.Filename] = new DecodedDirectoryEntry
                        {
                            Size                 = 0,
                            Flags                = record.flags ^ FileFlags.Associated,
                            FileUnitSize         = 0,
                            Interleave           = 0,
                            VolumeSequenceNumber = record.volume_sequence_number,
                            Filename             = entry.Filename,
                            Timestamp            = DecodeIsoDateTime(record.date),
                            XattrLength          = 0
                        };

                        if(hasResourceFork)
                            entries[entry.Filename].ResourceFork = entry;
                        else
                            entries[entry.Filename].AssociatedFile = entry;
                    }
                }
                else
                {
                    if(entries.ContainsKey(entry.Filename))
                    {
                        entries[entry.Filename].Size += entry.Size;

                        // Can appear after an associated file
                        if(entries[entry.Filename].Extents is null)
                        {
                            entries[entry.Filename].Extents              = new List<(uint extent, uint size)>();
                            entries[entry.Filename].Flags                = entry.Flags;
                            entries[entry.Filename].FileUnitSize         = entry.FileUnitSize;
                            entries[entry.Filename].Interleave           = entry.Interleave;
                            entries[entry.Filename].VolumeSequenceNumber = entry.VolumeSequenceNumber;
                            entries[entry.Filename].Filename             = entry.Filename;
                            entries[entry.Filename].Timestamp            = entry.Timestamp;
                            entries[entry.Filename].XattrLength          = entry.XattrLength;
                        }

                        if(entry.Extents?.Count > 0)
                            entries[entry.Filename].Extents.Add(entry.Extents[0]);
                    }
                    else
                        entries[entry.Filename] = entry;
                }

                entryOff += record.length;
            }

            if(_useTransTbl)
                DecodeTransTable(entries);

            // Relocated directories should be shown in correct place when using Rock Ridge namespace
            return _namespace == Namespace.Rrip
                       ? entries.Where(e => !e.Value.RockRidgeRelocated).ToDictionary(x => x.Key, x => x.Value)
                       : entries;
        }

        void DecodeTransTable(Dictionary<string, DecodedDirectoryEntry> entries)
        {
            KeyValuePair<string, DecodedDirectoryEntry> transTblEntry =
                entries.FirstOrDefault(e => !e.Value.Flags.HasFlag(FileFlags.Directory) &&
                                            (e.Value.Filename.ToLower(CultureInfo.CurrentUICulture) == "trans.tbl" ||
                                             e.Value.Filename.ToLower(CultureInfo.CurrentUICulture) == "trans.tbl;1"));

            if(transTblEntry.Value == null)
                return;

            byte[] transTbl = ReadWithExtents(0, (long)transTblEntry.Value.Size, transTblEntry.Value.Extents,
                                              transTblEntry.Value.XA?.signature == XA_MAGIC &&
                                              transTblEntry.Value.XA?.attributes.HasFlag(XaAttributes.Interleaved) ==
                                              true, transTblEntry.Value.XA?.filenumber ?? 0);

            var mr = new MemoryStream(transTbl, 0, (int)transTblEntry.Value.Size, false);
            var sr = new StreamReader(mr, Encoding);

            string line = sr.ReadLine();

            while(line != null)
            {
                // Skip the type field and the first space
                string cutLine      = line.Substring(2);
                int    spaceIndex   = cutLine.IndexOf(' ');
                string originalName = cutLine.Substring(0, spaceIndex);
                string originalNameWithVersion;
                string newName = cutLine.Substring(spaceIndex + 1).TrimStart();

                if(originalName.EndsWith(";1", StringComparison.Ordinal))
                {
                    originalNameWithVersion = originalName.ToLower(CultureInfo.CurrentUICulture);
                    originalName            = originalNameWithVersion.Substring(0, originalName.Length - 2);
                }
                else
                {
                    originalName            = originalName.ToLower(CultureInfo.CurrentUICulture);
                    originalNameWithVersion = originalName + ";1";
                }

                // Pre-read next line
                line = sr.ReadLine();

                KeyValuePair<string, DecodedDirectoryEntry> originalEntry =
                    entries.FirstOrDefault(e => !e.Value.Flags.HasFlag(FileFlags.Directory) &&
                                                (e.Value.Filename.ToLower(CultureInfo.CurrentUICulture) ==
                                                 originalName ||
                                                 e.Value.Filename.ToLower(CultureInfo.CurrentUICulture) ==
                                                 originalNameWithVersion));

                originalEntry.Value.Filename = newName;
                entries.Remove(originalEntry.Key);
                entries[newName] = originalEntry.Value;
            }

            entries.Remove(transTblEntry.Key);
        }

        void DecodeSystemArea(byte[] data, int start, int end, ref DecodedDirectoryEntry entry,
                              out bool hasResourceFork)
        {
            int systemAreaOff = start;
            hasResourceFork = false;
            bool              continueSymlink          = false;
            bool              continueSymlinkComponent = false;
            AppleCommon.FInfo fInfo;

            while(systemAreaOff + 2 <= end)
            {
                ushort systemAreaSignature = BigEndianBitConverter.ToUInt16(data, systemAreaOff);

                if(BigEndianBitConverter.ToUInt16(data, systemAreaOff + 6) == XA_MAGIC)
                    systemAreaSignature = XA_MAGIC;

                switch(systemAreaSignature)
                {
                    case APPLE_MAGIC:
                        byte appleLength = data[systemAreaOff + 2];
                        var  appleId     = (AppleId)data[systemAreaOff + 3];

                        // Old AAIP
                        if(appleId     == AppleId.ProDOS &&
                           appleLength != 7)
                            goto case AAIP_MAGIC;

                        switch(appleId)
                        {
                            case AppleId.ProDOS:
                                AppleProDOSSystemUse appleProDosSystemUse =
                                    Marshal.ByteArrayToStructureLittleEndian<AppleProDOSSystemUse>(data, systemAreaOff,
                                        Marshal.SizeOf<AppleProDOSSystemUse>());

                                entry.AppleProDosType = appleProDosSystemUse.aux_type;
                                entry.AppleDosType    = appleProDosSystemUse.type;

                                break;
                            case AppleId.HFS:
                                AppleHFSSystemUse appleHfsSystemUse =
                                    Marshal.ByteArrayToStructureBigEndian<AppleHFSSystemUse>(data, systemAreaOff,
                                        Marshal.SizeOf<AppleHFSSystemUse>());

                                hasResourceFork = true;

                                fInfo            = new AppleCommon.FInfo();
                                fInfo.fdCreator  = appleHfsSystemUse.creator;
                                fInfo.fdFlags    = appleHfsSystemUse.finder_flags;
                                fInfo.fdType     = appleHfsSystemUse.type;
                                entry.FinderInfo = fInfo;

                                break;
                        }

                        systemAreaOff += appleLength;

                        break;
                    case APPLE_MAGIC_OLD:
                        var appleOldId = (AppleOldId)data[systemAreaOff + 2];

                        switch(appleOldId)
                        {
                            case AppleOldId.ProDOS:
                                AppleProDOSOldSystemUse appleProDosOldSystemUse =
                                    Marshal.ByteArrayToStructureLittleEndian<AppleProDOSOldSystemUse>(data,
                                        systemAreaOff, Marshal.SizeOf<AppleProDOSOldSystemUse>());

                                entry.AppleProDosType = appleProDosOldSystemUse.aux_type;
                                entry.AppleDosType    = appleProDosOldSystemUse.type;

                                systemAreaOff += Marshal.SizeOf<AppleProDOSOldSystemUse>();

                                break;
                            case AppleOldId.TypeCreator:
                            case AppleOldId.TypeCreatorBundle:
                                AppleHFSTypeCreatorSystemUse appleHfsTypeCreatorSystemUse =
                                    Marshal.ByteArrayToStructureBigEndian<AppleHFSTypeCreatorSystemUse>(data,
                                        systemAreaOff, Marshal.SizeOf<AppleHFSTypeCreatorSystemUse>());

                                hasResourceFork = true;

                                fInfo            = new AppleCommon.FInfo();
                                fInfo.fdCreator  = appleHfsTypeCreatorSystemUse.creator;
                                fInfo.fdType     = appleHfsTypeCreatorSystemUse.type;
                                entry.FinderInfo = fInfo;

                                systemAreaOff += Marshal.SizeOf<AppleHFSTypeCreatorSystemUse>();

                                break;
                            case AppleOldId.TypeCreatorIcon:
                            case AppleOldId.TypeCreatorIconBundle:
                                AppleHFSIconSystemUse appleHfsIconSystemUse =
                                    Marshal.ByteArrayToStructureBigEndian<AppleHFSIconSystemUse>(data, systemAreaOff,
                                        Marshal.SizeOf<AppleHFSIconSystemUse>());

                                hasResourceFork = true;

                                fInfo            = new AppleCommon.FInfo();
                                fInfo.fdCreator  = appleHfsIconSystemUse.creator;
                                fInfo.fdType     = appleHfsIconSystemUse.type;
                                entry.FinderInfo = fInfo;
                                entry.AppleIcon  = appleHfsIconSystemUse.icon;

                                systemAreaOff += Marshal.SizeOf<AppleHFSIconSystemUse>();

                                break;
                            case AppleOldId.HFS:
                                AppleHFSOldSystemUse appleHfsSystemUse =
                                    Marshal.ByteArrayToStructureBigEndian<AppleHFSOldSystemUse>(data, systemAreaOff,
                                        Marshal.SizeOf<AppleHFSOldSystemUse>());

                                hasResourceFork = true;

                                fInfo            = new AppleCommon.FInfo();
                                fInfo.fdCreator  = appleHfsSystemUse.creator;
                                fInfo.fdFlags    = (AppleCommon.FinderFlags)appleHfsSystemUse.finder_flags;
                                fInfo.fdType     = appleHfsSystemUse.type;
                                entry.FinderInfo = fInfo;

                                systemAreaOff += Marshal.SizeOf<AppleHFSOldSystemUse>();

                                break;
                            default:
                                // Cannot continue as we don't know this structure size
                                systemAreaOff = end;

                                break;
                        }

                        break;
                    case XA_MAGIC:
                        entry.XA = Marshal.ByteArrayToStructureBigEndian<CdromXa>(data, systemAreaOff,
                            Marshal.SizeOf<CdromXa>());

                        systemAreaOff += Marshal.SizeOf<CdromXa>();

                        break;

                    // All of these follow the SUSP indication of 2 bytes for signature 1 byte for length
                    case AAIP_MAGIC:
                    case AMIGA_MAGIC:
                        AmigaEntry amiga =
                            Marshal.ByteArrayToStructureBigEndian<AmigaEntry>(data, systemAreaOff,
                                                                              Marshal.SizeOf<AmigaEntry>());

                        int protectionLength = 0;

                        if(amiga.flags.HasFlag(AmigaFlags.Protection))
                        {
                            entry.AmigaProtection =
                                Marshal.ByteArrayToStructureBigEndian<AmigaProtection>(data,
                                    systemAreaOff + Marshal.SizeOf<AmigaEntry>(),
                                    Marshal.SizeOf<AmigaProtection>());

                            protectionLength = Marshal.SizeOf<AmigaProtection>();
                        }

                        if(amiga.flags.HasFlag(AmigaFlags.Comment))
                        {
                            if(entry.AmigaComment is null)
                                entry.AmigaComment = new byte[0];

                            byte[] newComment = new byte[(entry.AmigaComment.Length +
                                                          data
                                                              [systemAreaOff + Marshal.SizeOf<AmigaEntry>() + protectionLength]
                                                         ) - 1];

                            Array.Copy(entry.AmigaComment, 0, newComment, 0, entry.AmigaComment.Length);

                            Array.Copy(data, systemAreaOff + Marshal.SizeOf<AmigaEntry>() + protectionLength,
                                       newComment, entry.AmigaComment.Length,
                                       data[systemAreaOff + Marshal.SizeOf<AmigaEntry>() + protectionLength] - 1);

                            entry.AmigaComment = newComment;
                        }

                        systemAreaOff += amiga.length;

                        break;

                    // This merely indicates the existence of RRIP extensions, we don't need it
                    case RRIP_MAGIC:
                        byte rripLength = data[systemAreaOff + 2];
                        systemAreaOff += rripLength;

                        break;
                    case RRIP_POSIX_ATTRIBUTES:
                        byte pxLength = data[systemAreaOff + 2];

                        if(pxLength == 36)
                            entry.PosixAttributesOld =
                                Marshal.ByteArrayToStructureLittleEndian<PosixAttributesOld>(data, systemAreaOff,
                                    Marshal.SizeOf<PosixAttributesOld>());
                        else if(pxLength >= 44)
                            entry.PosixAttributes =
                                Marshal.ByteArrayToStructureLittleEndian<PosixAttributes>(data, systemAreaOff,
                                    Marshal.SizeOf<PosixAttributes>());

                        systemAreaOff += pxLength;

                        break;
                    case RRIP_POSIX_DEV_NO:
                        byte pnLength = data[systemAreaOff + 2];

                        entry.PosixDeviceNumber =
                            Marshal.ByteArrayToStructureLittleEndian<PosixDeviceNumber>(data, systemAreaOff,
                                Marshal.SizeOf<PosixDeviceNumber>());

                        systemAreaOff += pnLength;

                        break;
                    case RRIP_SYMLINK:
                        byte slLength = data[systemAreaOff + 2];

                        SymbolicLink sl =
                            Marshal.ByteArrayToStructureLittleEndian<SymbolicLink>(data, systemAreaOff,
                                Marshal.SizeOf<SymbolicLink>());

                        SymbolicLinkComponent slc =
                            Marshal.ByteArrayToStructureLittleEndian<SymbolicLinkComponent>(data,
                                systemAreaOff + Marshal.SizeOf<SymbolicLink>(),
                                Marshal.SizeOf<SymbolicLinkComponent>());

                        if(!continueSymlink ||
                           entry.SymbolicLink is null)
                            entry.SymbolicLink = "";

                        if(slc.flags.HasFlag(SymlinkComponentFlags.Root))
                            entry.SymbolicLink = "/";

                        if(slc.flags.HasFlag(SymlinkComponentFlags.Current))
                            entry.SymbolicLink += ".";

                        if(slc.flags.HasFlag(SymlinkComponentFlags.Parent))
                            entry.SymbolicLink += "..";

                        if(!continueSymlinkComponent &&
                           !slc.flags.HasFlag(SymlinkComponentFlags.Root))
                            entry.SymbolicLink += "/";

                        entry.SymbolicLink += slc.flags.HasFlag(SymlinkComponentFlags.Networkname)
                                                  ? Environment.MachineName
                                                  : _joliet
                                                      ? Encoding.BigEndianUnicode.GetString(data,
                                                          systemAreaOff + Marshal.SizeOf<SymbolicLink>() +
                                                          Marshal.SizeOf<SymbolicLinkComponent>(), slc.length)
                                                      : Encoding.GetString(data,
                                                                           systemAreaOff                  +
                                                                           Marshal.SizeOf<SymbolicLink>() +
                                                                           Marshal.SizeOf<SymbolicLinkComponent>(),
                                                                           slc.length);

                        continueSymlink          = sl.flags.HasFlag(SymlinkFlags.Continue);
                        continueSymlinkComponent = slc.flags.HasFlag(SymlinkComponentFlags.Continue);

                        systemAreaOff += slLength;

                        break;
                    case RRIP_NAME:
                        byte nmLength = data[systemAreaOff + 2];

                        if(_namespace != Namespace.Rrip)
                        {
                            systemAreaOff += nmLength;

                            break;
                        }

                        AlternateName alternateName =
                            Marshal.ByteArrayToStructureLittleEndian<AlternateName>(data, systemAreaOff,
                                Marshal.SizeOf<AlternateName>());

                        byte[] nm;

                        if(alternateName.flags.HasFlag(AlternateNameFlags.Networkname))
                            nm = _joliet ? Encoding.BigEndianUnicode.GetBytes(Environment.MachineName)
                                     : Encoding.GetBytes(Environment.MachineName);
                        else
                        {
                            nm = new byte[nmLength - Marshal.SizeOf<AlternateName>()];

                            Array.Copy(data, systemAreaOff + Marshal.SizeOf<AlternateName>(), nm, 0, nm.Length);
                        }

                        if(entry.RockRidgeAlternateName is null)
                            entry.RockRidgeAlternateName = new byte[0];

                        byte[] newNm = new byte[entry.RockRidgeAlternateName.Length + nm.Length];
                        Array.Copy(entry.RockRidgeAlternateName, 0, newNm, 0, entry.RockRidgeAlternateName.Length);
                        Array.Copy(nm, 0, newNm, entry.RockRidgeAlternateName.Length, nm.Length);

                        entry.RockRidgeAlternateName = newNm;

                        if(!alternateName.flags.HasFlag(AlternateNameFlags.Continue))
                        {
                            entry.Filename = _joliet ? Encoding.BigEndianUnicode.GetString(entry.RockRidgeAlternateName)
                                                 : Encoding.GetString(entry.RockRidgeAlternateName);

                            entry.RockRidgeAlternateName = null;
                        }

                        systemAreaOff += nmLength;

                        break;
                    case RRIP_CHILDLINK:
                        byte clLength = data[systemAreaOff + 2];

                        // If we are not in Rock Ridge namespace, or we are using the Path Table, skip it
                        if(_namespace != Namespace.Rrip || _usePathTable)
                        {
                            systemAreaOff += clLength;

                            break;
                        }

                        ChildLink cl =
                            Marshal.ByteArrayToStructureLittleEndian<ChildLink>(data, systemAreaOff,
                                                                                    Marshal.SizeOf<ChildLink>());

                        byte[] childSector = ReadSector(cl.child_dir_lba);

                        DirectoryRecord childRecord =
                            Marshal.ByteArrayToStructureLittleEndian<DirectoryRecord>(childSector);

                        // As per RRIP 4.1.5.1, we leave name as in previous entry, substitute location with the one in
                        // the CL, and replace all other fields with the ones found in the first entry of the child
                        entry.Extents = new List<(uint extent, uint size)>
                        {
                            (cl.child_dir_lba, childRecord.size)
                        };

                        entry.Size                 = childRecord.size;
                        entry.Flags                = childRecord.flags;
                        entry.FileUnitSize         = childRecord.file_unit_size;
                        entry.Interleave           = childRecord.interleave;
                        entry.VolumeSequenceNumber = childRecord.volume_sequence_number;
                        entry.Timestamp            = DecodeIsoDateTime(childRecord.date);
                        entry.XattrLength          = childRecord.xattr_len;

                        systemAreaOff += clLength;

                        break;
                    case RRIP_PARENTLINK:
                        // SKip, we don't need it
                        byte plLength = data[systemAreaOff + 2];
                        systemAreaOff += plLength;

                        break;
                    case RRIP_RELOCATED_DIR:
                        byte reLength = data[systemAreaOff + 2];
                        systemAreaOff += reLength;

                        entry.RockRidgeRelocated = true;

                        break;
                    case RRIP_TIMESTAMPS:
                        byte tfLength = data[systemAreaOff + 2];

                        Timestamps timestamps =
                            Marshal.ByteArrayToStructureLittleEndian<Timestamps>(data, systemAreaOff,
                                Marshal.SizeOf<Timestamps>());

                        int tfOff = systemAreaOff + Marshal.SizeOf<Timestamps>();
                        int tfLen = timestamps.flags.HasFlag(TimestampFlags.LongFormat) ? 17 : 7;

                        if(timestamps.flags.HasFlag(TimestampFlags.Creation))
                        {
                            entry.RripCreation = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripCreation, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.Modification))
                        {
                            entry.RripModify = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripModify, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.Access))
                        {
                            entry.RripAccess = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripAccess, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.AttributeChange))
                        {
                            entry.RripAttributeChange = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripAttributeChange, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.Backup))
                        {
                            entry.RripBackup = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripBackup, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.Expiration))
                        {
                            entry.RripExpiration = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripExpiration, 0, tfLen);
                            tfOff += tfLen;
                        }

                        if(timestamps.flags.HasFlag(TimestampFlags.Effective))
                        {
                            entry.RripEffective = new byte[tfLen];
                            Array.Copy(data, tfOff, entry.RripEffective, 0, tfLen);
                        }

                        systemAreaOff += tfLength;

                        break;
                    case RRIP_SPARSE:
                        // TODO
                        byte sfLength = data[systemAreaOff + 2];
                        systemAreaOff += sfLength;

                        break;
                    case SUSP_CONTINUATION:
                        byte ceLength = data[systemAreaOff + 2];

                        ContinuationArea ca =
                            Marshal.ByteArrayToStructureLittleEndian<ContinuationArea>(data, systemAreaOff,
                                Marshal.SizeOf<ContinuationArea>());

                        byte[] caData = ReadSingleExtent(ca.offset, ca.ca_length, ca.block);

                        DecodeSystemArea(caData, 0, (int)ca.ca_length, ref entry, out hasResourceFork);

                        systemAreaOff += ceLength;

                        break;
                    case SUSP_PADDING:
                        // Just padding, skip
                        byte pdLength = data[systemAreaOff + 2];
                        systemAreaOff += pdLength;

                        break;
                    case SUSP_INDICATOR:
                        // Only to be found on CURRENT entry of root directory
                        byte spLength = data[systemAreaOff + 2];
                        systemAreaOff += spLength;

                        break;
                    case SUSP_TERMINATOR:
                        // Not seen on the wild
                        byte stLength = data[systemAreaOff + 2];
                        systemAreaOff += stLength;

                        break;
                    case SUSP_REFERENCE:
                        // Only to be found on CURRENT entry of root directory
                        byte erLength = data[systemAreaOff + 2];
                        systemAreaOff += erLength;

                        break;
                    case SUSP_SELECTOR:
                        // Only to be found on CURRENT entry of root directory
                        byte esLength = data[systemAreaOff + 2];
                        systemAreaOff += esLength;

                        break;
                    case ZISO_MAGIC:
                        // TODO: Implement support for zisofs
                        byte zfLength = data[systemAreaOff + 2];
                        systemAreaOff += zfLength;

                        break;
                    default:
                        // Cannot continue as we don't know this structure size
                        systemAreaOff = end;

                        break;
                }
            }
        }

        PathTableEntryInternal[] GetPathTableEntries(string path)
        {
            IEnumerable<PathTableEntryInternal> tableEntries;
            List<PathTableEntryInternal>        pathTableList = new List<PathTableEntryInternal>(_pathTable);

            if(path == "" ||
               path == "/")
                tableEntries = _pathTable.Where(p => p.Parent == 1 && p != _pathTable[0]);
            else
            {
                string cutPath = path.StartsWith("/", StringComparison.Ordinal)
                                     ? path.Substring(1).ToLower(CultureInfo.CurrentUICulture)
                                     : path.ToLower(CultureInfo.CurrentUICulture);

                string[] pieces = cutPath.Split(new[]
                {
                    '/'
                }, StringSplitOptions.RemoveEmptyEntries);

                int currentParent = 1;
                int currentPiece  = 0;

                while(currentPiece < pieces.Length)
                {
                    PathTableEntryInternal currentEntry = _pathTable.FirstOrDefault(p => p.Parent == currentParent &&
                        p.Name.ToLower(CultureInfo.CurrentUICulture) == pieces[currentPiece]);

                    if(currentEntry is null)
                        break;

                    currentPiece++;
                    currentParent = pathTableList.IndexOf(currentEntry) + 1;
                }

                tableEntries = _pathTable.Where(p => p.Parent == currentParent);
            }

            return tableEntries.ToArray();
        }

        DecodedDirectoryEntry[] GetSubdirsFromCdiPathTable(string path)
        {
            PathTableEntryInternal[]    tableEntries = GetPathTableEntries(path);
            List<DecodedDirectoryEntry> entries      = new List<DecodedDirectoryEntry>();

            foreach(PathTableEntryInternal tEntry in tableEntries)
            {
                byte[] sector = ReadSector(tEntry.Extent);

                CdiDirectoryRecord record =
                    Marshal.ByteArrayToStructureBigEndian<CdiDirectoryRecord>(sector, tEntry.XattrLength,
                                                                              _cdiDirectoryRecordSize);

                if(record.length == 0)
                    break;

                var entry = new DecodedDirectoryEntry
                {
                    Size                 = record.size,
                    Filename             = tEntry.Name,
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Timestamp            = DecodeHighSierraDateTime(record.date),
                    XattrLength          = tEntry.XattrLength
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.start_lbn, record.size)
                    };

                if(record.flags.HasFlag(CdiFileFlags.Hidden))
                    entry.Flags |= FileFlags.Hidden;

                int systemAreaStart = record.name_len + _cdiDirectoryRecordSize;

                if(systemAreaStart % 2 != 0)
                    systemAreaStart++;

                entry.CdiSystemArea =
                    Marshal.ByteArrayToStructureBigEndian<CdiSystemArea>(sector, systemAreaStart, _cdiSystemAreaSize);

                if(entry.CdiSystemArea.Value.attributes.HasFlag(CdiAttributes.Directory))
                    entry.Flags |= FileFlags.Directory;

                entries.Add(entry);
            }

            return entries.ToArray();
        }

        DecodedDirectoryEntry[] GetSubdirsFromIsoPathTable(string path)
        {
            PathTableEntryInternal[]    tableEntries = GetPathTableEntries(path);
            List<DecodedDirectoryEntry> entries      = new List<DecodedDirectoryEntry>();

            foreach(PathTableEntryInternal tEntry in tableEntries)
            {
                byte[] sector = ReadSector(tEntry.Extent);

                DirectoryRecord record =
                    Marshal.ByteArrayToStructureLittleEndian<DirectoryRecord>(sector, tEntry.XattrLength,
                                                                              _directoryRecordSize);

                if(record.length == 0)
                    break;

                var entry = new DecodedDirectoryEntry
                {
                    Size                 = record.size,
                    Flags                = record.flags,
                    Filename             = tEntry.Name,
                    FileUnitSize         = record.file_unit_size,
                    Interleave           = record.interleave,
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Timestamp            = DecodeIsoDateTime(record.date),
                    XattrLength          = tEntry.XattrLength
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.extent, record.size)
                    };

                int systemAreaStart  = record.name_len + _directoryRecordSize;
                int systemAreaLength = record.length   - record.name_len - _directoryRecordSize;

                if(systemAreaStart % 2 != 0)
                {
                    systemAreaStart++;
                    systemAreaLength--;
                }

                DecodeSystemArea(sector, systemAreaStart, systemAreaStart + systemAreaLength, ref entry, out _);

                entries.Add(entry);
            }

            return entries.ToArray();
        }

        DecodedDirectoryEntry[] GetSubdirsFromHighSierraPathTable(string path)
        {
            PathTableEntryInternal[]    tableEntries = GetPathTableEntries(path);
            List<DecodedDirectoryEntry> entries      = new List<DecodedDirectoryEntry>();

            foreach(PathTableEntryInternal tEntry in tableEntries)
            {
                byte[] sector = ReadSector(tEntry.Extent);

                HighSierraDirectoryRecord record =
                    Marshal.ByteArrayToStructureLittleEndian<HighSierraDirectoryRecord>(sector, tEntry.XattrLength,
                        _highSierraDirectoryRecordSize);

                var entry = new DecodedDirectoryEntry
                {
                    Size                 = record.size,
                    Flags                = record.flags,
                    Filename             = tEntry.Name,
                    Interleave           = record.interleave,
                    VolumeSequenceNumber = record.volume_sequence_number,
                    Timestamp            = DecodeHighSierraDateTime(record.date),
                    XattrLength          = tEntry.XattrLength
                };

                if(record.size != 0)
                    entry.Extents = new List<(uint extent, uint size)>
                    {
                        (record.extent, record.size)
                    };

                entries.Add(entry);
            }

            return entries.ToArray();
        }
    }
}