Add support for Zstandard compressed files with a new Zstd filter

Aaru.Filters/Zstd.cs

@@ -0,0 +1,194 @@
+// /***************************************************************************
+// Aaru Data Preservation Suite
+// ----------------------------------------------------------------------------
+//
+// Filename       : Zstd.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : Filters.
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Allow to open files that are compressed using Zstd.
+//
+// --[ 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 © 2011-2026 Natalia Portillo
+// ****************************************************************************/
+
+using System;
+using System.IO;
+using Aaru.CommonTypes.Enums;
+using Aaru.CommonTypes.Interfaces;
+using Aaru.Helpers;
+using Aaru.Helpers.IO;
+using SharpCompress.Providers.Default;
+
+namespace Aaru.Filters;
+
+/// <inheritdoc />
+/// <summary>Decompress Zstd files while reading</summary>
+public sealed class Zstd : IFilter
+{
+    Stream _dataStream;
+    Stream _innerStream;
+
+#region IFilter Members
+
+    /// <inheritdoc />
+    public string Name => "Zstd";
+
+    /// <inheritdoc />
+    public Guid Id => new("3BA80B07-66EE-4439-8EF5-3EB4D9D668F7");
+
+    /// <inheritdoc />
+    public string Author => Authors.NataliaPortillo;
+
+    /// <inheritdoc />
+    public void Close()
+    {
+        _dataStream?.Close();
+        _dataStream = null;
+        BasePath    = null;
+    }
+
+    /// <inheritdoc />
+    public string BasePath { get; private set; }
+
+    /// <inheritdoc />
+    public Stream GetDataForkStream() => _innerStream;
+
+    /// <inheritdoc />
+    public string Path => BasePath;
+
+    /// <inheritdoc />
+    public Stream GetResourceForkStream() => null;
+
+    /// <inheritdoc />
+    public bool HasResourceFork => false;
+
+    /// <inheritdoc />
+    public bool Identify(byte[] buffer) => buffer[0] == 0x28 &&
+                                           buffer[1] == 0xB5 &&
+                                           buffer[2] == 0x2F &&
+                                           buffer[3] == 0xFD;
+
+    /// <inheritdoc />
+    public bool Identify(Stream stream)
+    {
+        var buffer = new byte[4];
+
+        if(stream.Length < 4) return false;
+
+        stream.Seek(0, SeekOrigin.Begin);
+        stream.EnsureRead(buffer, 0, 4);
+        stream.Seek(0, SeekOrigin.Begin);
+
+        return buffer[0] == 0x28 && buffer[1] == 0xB5 && buffer[2] == 0x2F && buffer[3] == 0xFD;
+    }
+
+    /// <inheritdoc />
+    public bool Identify(string path)
+    {
+        if(!File.Exists(path)) return false;
+
+        var stream = new FileStream(path, FileMode.Open, FileAccess.Read);
+        var buffer = new byte[4];
+
+        if(stream.Length < 8) return false;
+
+        stream.Seek(0, SeekOrigin.Begin);
+        stream.EnsureRead(buffer, 0, 4);
+        stream.Seek(0, SeekOrigin.Begin);
+
+        return buffer[0] == 0x28 && buffer[1] == 0xB5 && buffer[2] == 0x2F && buffer[3] == 0xFD;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber Open(byte[] buffer)
+    {
+        _dataStream   = new MemoryStream(buffer);
+        BasePath      = null;
+        CreationTime  = DateTime.UtcNow;
+        LastWriteTime = CreationTime;
+        var provider = new ZStandardCompressionProvider();
+        _innerStream = new ForcedSeekStream<Stream>(provider.CreateDecompressStream(_dataStream));
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber Open(Stream stream)
+    {
+        _dataStream   = stream;
+        BasePath      = null;
+        CreationTime  = DateTime.UtcNow;
+        LastWriteTime = CreationTime;
+        var provider = new ZStandardCompressionProvider();
+        _innerStream = new ForcedSeekStream<Stream>(provider.CreateDecompressStream(_dataStream));
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber Open(string path)
+    {
+        _dataStream = new FileStream(path, FileMode.Open, FileAccess.Read);
+        BasePath    = System.IO.Path.GetFullPath(path);
+
+        var fi = new FileInfo(path);
+        CreationTime  = fi.CreationTimeUtc;
+        LastWriteTime = fi.LastWriteTimeUtc;
+        var provider = new ZStandardCompressionProvider();
+        _innerStream = new ForcedSeekStream<Stream>(provider.CreateDecompressStream(_dataStream));
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public DateTime CreationTime { get; private set; }
+
+    /// <inheritdoc />
+    public long DataForkLength { get; private set; }
+
+    /// <inheritdoc />
+    public DateTime LastWriteTime { get; private set; }
+
+    /// <inheritdoc />
+    public long Length => DataForkLength;
+
+    /// <inheritdoc />
+    public long ResourceForkLength => 0;
+
+    /// <inheritdoc />
+    public string Filename
+    {
+        get
+        {
+            if(BasePath?.EndsWith(".zst", StringComparison.InvariantCultureIgnoreCase) == true) return BasePath[..^4];
+
+            return BasePath?.EndsWith(".zstd", StringComparison.InvariantCultureIgnoreCase) == true
+                       ? BasePath[..^5]
+                       : BasePath;
+        }
+    }
+
+    /// <inheritdoc />
+    public string ParentFolder => System.IO.Path.GetDirectoryName(BasePath);
+
+#endregion
+}

README.md

@@ -325,6 +325,7 @@ Supported filters
 * LZip
 * MacBinary I, II, III
 * XZ
+* ZStandard
 
 Partially supported disk image formats
 ======================================