134 lines
3.8 KiB
C#
134 lines
3.8 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2018 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version. For more
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* information, see COPYING.
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*/
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#endregion
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using ICSharpCode.SharpZipLib.Zip.Compression;
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using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
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namespace OpenRA.Mods.Common.FileFormats
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{
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public sealed class MSCabCompression
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{
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class CabFolder
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{
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public readonly uint BlockOffset;
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public readonly ushort BlockCount;
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public readonly ushort CompressionType;
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public CabFolder(Stream stream)
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{
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BlockOffset = stream.ReadUInt32();
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BlockCount = stream.ReadUInt16();
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CompressionType = stream.ReadUInt16();
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}
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}
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class CabFile
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{
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public readonly string FileName;
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public readonly uint DecompressedLength;
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public readonly uint DecompressedOffset;
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public readonly ushort FolderIndex;
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public CabFile(Stream stream)
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{
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DecompressedLength = stream.ReadUInt32();
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DecompressedOffset = stream.ReadUInt32();
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FolderIndex = stream.ReadUInt16();
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stream.Position += 6;
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FileName = stream.ReadASCIIZ();
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}
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}
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readonly CabFolder[] folders;
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readonly CabFile[] files;
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readonly Stream stream;
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public MSCabCompression(Stream stream)
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{
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this.stream = stream;
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var signature = stream.ReadASCII(4);
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if (signature != "MSCF")
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throw new InvalidDataException("Not a Microsoft CAB package!");
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stream.Position += 12;
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var filesOffset = stream.ReadUInt32();
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stream.Position += 6;
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var folderCount = stream.ReadUInt16();
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var fileCount = stream.ReadUInt16();
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if (stream.ReadUInt16() != 0)
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throw new InvalidDataException("Only plain packages (without reserved header space or prev/next archives) are supported!");
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stream.Position += 4;
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folders = new CabFolder[folderCount];
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for (var i = 0; i < folderCount; i++)
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{
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folders[i] = new CabFolder(stream);
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if (folders[i].CompressionType != 1)
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throw new InvalidDataException("Compression type is not supported");
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}
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files = new CabFile[fileCount];
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stream.Seek(filesOffset, SeekOrigin.Begin);
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for (var i = 0; i < fileCount; i++)
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files[i] = new CabFile(stream);
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}
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public void ExtractFile(string filename, Stream output, Action<int> onProgress = null)
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{
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var file = files.FirstOrDefault(f => f.FileName == filename);
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if (file == null)
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throw new FileNotFoundException(filename);
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var folder = folders[file.FolderIndex];
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stream.Seek(folder.BlockOffset, SeekOrigin.Begin);
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var inflater = new Inflater(true);
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var buffer = new byte[4096];
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var decompressedBytes = 0;
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for (var i = 0; i < folder.BlockCount; i++)
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{
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if (onProgress != null)
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onProgress((int)(100 * output.Position / file.DecompressedLength));
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// Ignore checksums
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stream.Position += 4;
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var blockLength = stream.ReadUInt16();
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stream.Position += 4;
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using (var batch = new MemoryStream(stream.ReadBytes(blockLength - 2)))
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using (var inflaterStream = new InflaterInputStream(batch, inflater))
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{
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int n;
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while ((n = inflaterStream.Read(buffer, 0, buffer.Length)) > 0)
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{
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var offset = Math.Max(0, file.DecompressedOffset - decompressedBytes);
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var count = Math.Min(n - offset, file.DecompressedLength - decompressedBytes);
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if (offset < n)
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output.Write(buffer, (int)offset, (int)count);
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decompressedBytes += n;
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}
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}
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inflater.Reset();
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}
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}
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public IEnumerable<string> Contents { get { return files.Select(f => f.FileName); } }
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}
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}
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