SabreTools.Serialization/Wrappers/GCF.cs

using System.Collections.Generic;
using System.IO;
using SabreTools.Models.CHD;
using SabreTools.Models.CueSheets;

namespace SabreTools.Serialization.Wrappers
{
    public class GCF : WrapperBase<Models.GCF.File>
    {
        #region Descriptive Properties

        /// <inheritdoc/>
        public override string DescriptionString => "Half-Life Game Cache File (GCF)";

        #endregion

        #region Extension Properties

        /// <summary>
        /// Set of all files and their information
        /// </summary>
        public FileInfo[]? Files
        {
            get
            {
                // Use the cached value if we have it
                if (_files != null)
                    return _files;

                // If we don't have a required property
                if (this.Model.DirectoryEntries == null || this.Model.DirectoryMapEntries == null || this.Model.BlockEntries == null)
                    return null;

                // Otherwise, scan and build the files
                var files = new List<FileInfo>();
                for (int i = 0; i < this.Model.DirectoryEntries.Length; i++)
                {
                    // Get the directory entry
                    var directoryEntry = this.Model.DirectoryEntries[i];
                    var directoryMapEntry = this.Model.DirectoryMapEntries[i];
                    if (directoryEntry == null || directoryMapEntry == null)
                        continue;

                    // If we have a directory, skip for now
#if NET20 || NET35
                    if ((directoryEntry.DirectoryFlags & Models.GCF.HL_GCF_FLAG.HL_GCF_FLAG_FILE) == 0)
#else
                    if (!directoryEntry.DirectoryFlags.HasFlag(Models.GCF.HL_GCF_FLAG.HL_GCF_FLAG_FILE))
#endif
                        continue;

                    // Otherwise, start building the file info
                    var fileInfo = new FileInfo()
                    {
                        Size = directoryEntry.ItemSize,
#if NET20 || NET35
                        Encrypted = (directoryEntry.DirectoryFlags & Models.GCF.HL_GCF_FLAG.HL_GCF_FLAG_ENCRYPTED) != 0,
#else
                        Encrypted = directoryEntry.DirectoryFlags.HasFlag(Models.GCF.HL_GCF_FLAG.HL_GCF_FLAG_ENCRYPTED),
#endif
                    };
                    var pathParts = new List<string> { directoryEntry.Name ?? string.Empty };
                    var blockEntries = new List<Models.GCF.BlockEntry?>();

                    // Traverse the parent tree
                    uint index = directoryEntry.ParentIndex;
                    while (index != 0xFFFFFFFF)
                    {
                        var parentDirectoryEntry = this.Model.DirectoryEntries[index];
                        if (parentDirectoryEntry == null)
                            break;

                        pathParts.Add(parentDirectoryEntry.Name ?? string.Empty);
                        index = parentDirectoryEntry.ParentIndex;
                    }

                    // Traverse the block entries
                    index = directoryMapEntry.FirstBlockIndex;
                    while (index != this.Model.DataBlockHeader?.BlockCount)
                    {
                        var nextBlock = this.Model.BlockEntries[index];
                        if (nextBlock == null)
                            break;

                        blockEntries.Add(nextBlock);
                        index = nextBlock.NextBlockEntryIndex;
                    }

                    // Reverse the path parts because of traversal
                    pathParts.Reverse();

                    // Build the remaining file info
#if NET20 || NET35
                    var pathArray = pathParts.ToArray();

                    string tempPath = string.Empty;
                    if (pathArray.Length == 0 || pathArray.Length == 1)
                    {
                        tempPath = pathArray[0];
                    }
                    else
                    {
                        for (int j = 0; j < pathArray.Length; j++)
                        {
                            if (j == 0)
                                tempPath = pathArray[j];
                            else
                                tempPath = Path.Combine(tempPath, pathArray[j]);
                        }
                    }
                    fileInfo.Path = tempPath;
#else
                    fileInfo.Path = Path.Combine(pathParts.ToArray());
#endif
                    fileInfo.BlockEntries = [.. blockEntries];

                    // Add the file info and continue
                    files.Add(fileInfo);
                }

                // Set and return the file infos
                _files = [.. files];
                return _files;
            }
        }

        /// <summary>
        /// Set of all data block offsets
        /// </summary>
        public long[]? DataBlockOffsets
        {
            get
            {
                // Use the cached value if we have it
                if (_dataBlockOffsets != null)
                    return _dataBlockOffsets;

                // If we don't have a block count, offset, or size
                if (this.Model.DataBlockHeader?.BlockCount == null || this.Model.DataBlockHeader?.FirstBlockOffset == null || this.Model.DataBlockHeader?.BlockSize == null)
                    return null;

                // Otherwise, build the data block set
                _dataBlockOffsets = new long[this.Model.DataBlockHeader.BlockCount];
                for (int i = 0; i < this.Model.DataBlockHeader.BlockCount; i++)
                {
                    long dataBlockOffset = this.Model.DataBlockHeader.FirstBlockOffset + (i * this.Model.DataBlockHeader.BlockSize);
                    _dataBlockOffsets[i] = dataBlockOffset;
                }

                // Return the set of data blocks
                return _dataBlockOffsets;
            }
        }

        #endregion

        #region Instance Variables

        /// <summary>
        /// Set of all files and their information
        /// </summary>
        private FileInfo[]? _files = null;

        /// <summary>
        /// Set of all data block offsets
        /// </summary>
        private long[]? _dataBlockOffsets = null;

        #endregion

        #region Constructors

        /// <inheritdoc/>
        public GCF(Models.GCF.File? model, byte[]? data, int offset)
            : base(model, data, offset)
        {
            // All logic is handled by the base class
        }

        /// <inheritdoc/>
        public GCF(Models.GCF.File? model, Stream? data)
            : base(model, data)
        {
            // All logic is handled by the base class
        }

        /// <summary>
        /// Create an GCF from a byte array and offset
        /// </summary>
        /// <param name="data">Byte array representing the GCF</param>
        /// <param name="offset">Offset within the array to parse</param>
        /// <returns>An GCF wrapper on success, null on failure</returns>
        public static GCF? Create(byte[]? data, int offset)
        {
            // If the data is invalid
            if (data == null)
                return null;

            // If the offset is out of bounds
            if (offset < 0 || offset >= data.Length)
                return null;

            // Create a memory stream and use that
            var dataStream = new MemoryStream(data, offset, data.Length - offset);
            return Create(dataStream);
        }

        /// <summary>
        /// Create a GCF from a Stream
        /// </summary>
        /// <param name="data">Stream representing the GCF</param>
        /// <returns>An GCF wrapper on success, null on failure</returns>
        public static GCF? Create(Stream? data)
        {
            // If the data is invalid
            if (data == null || data.Length == 0 || !data.CanSeek || !data.CanRead)
                return null;

            var file = new Streams.GCF().Deserialize(data);
            if (file == null)
                return null;

            try
            {
                return new GCF(file, data);
            }
            catch
            {
                return null;
            }
        }

        #endregion

        #region Helper Classes

        /// <summary>
        /// Class to contain all necessary file information
        /// </summary>
        public sealed class FileInfo
        {
            /// <summary>
            /// Full item path
            /// </summary>
            public string? Path;

            /// <summary>
            /// File size
            /// </summary>
            public uint Size;

            /// <summary>
            /// Indicates if the block is encrypted
            /// </summary>
            public bool Encrypted;

            /// <summary>
            /// Array of block entries
            /// </summary>
            public SabreTools.Models.GCF.BlockEntry?[]? BlockEntries;
        }

        #endregion
    }
}