Consolidate

src/SharpCompress/Archives/GZip/GZipArchive.cs

@@ -87,7 +87,11 @@ public partial class GZipArchive
         var stream = volumes.Single().Stream;
         yield return new GZipArchiveEntry(
             this,
-            GZipFilePart.Create(stream, ReaderOptions.ArchiveEncoding),
+            GZipFilePart.Create(
+                stream,
+                ReaderOptions.ArchiveEncoding,
+                ReaderOptions.CompressionProviders
+            ),
             ReaderOptions
         );
     }

src/SharpCompress/Archives/Zip/ZipArchive.Async.cs

@@ -55,7 +55,12 @@ public partial class ZipArchive
 
                             yield return new ZipArchiveEntry(
                                 this,
-                                new SeekableZipFilePart(headerFactory.NotNull(), deh, s),
+                                new SeekableZipFilePart(
+                                    headerFactory.NotNull(),
+                                    deh,
+                                    s,
+                                    ReaderOptions.CompressionProviders
+                                ),
                                 ReaderOptions
                             );
                         }

src/SharpCompress/Archives/Zip/ZipArchive.cs

@@ -96,7 +96,12 @@ public partial class ZipArchive
 
                             yield return new ZipArchiveEntry(
                                 this,
-                                new SeekableZipFilePart(headerFactory.NotNull(), deh, s),
+                                new SeekableZipFilePart(
+                                    headerFactory.NotNull(),
+                                    deh,
+                                    s,
+                                    ReaderOptions.CompressionProviders
+                                ),
                                 ReaderOptions
                             );
                         }

src/SharpCompress/Common/GZip/GZipEntry.Async.cs

@@ -12,7 +12,9 @@ public partial class GZipEntry
     )
     {
         yield return new GZipEntry(
-            await GZipFilePart.CreateAsync(stream, options.ArchiveEncoding).ConfigureAwait(false),
+            await GZipFilePart
+                .CreateAsync(stream, options.ArchiveEncoding, options.CompressionProviders)
+                .ConfigureAwait(false),
             options
         );
     }

src/SharpCompress/Common/GZip/GZipEntry.cs

@@ -46,7 +46,10 @@ public partial class GZipEntry : Entry
 
     internal static IEnumerable<GZipEntry> GetEntries(Stream stream, ReaderOptions options)
     {
-        yield return new GZipEntry(GZipFilePart.Create(stream, options.ArchiveEncoding), options);
+        yield return new GZipEntry(
+            GZipFilePart.Create(stream, options.ArchiveEncoding, options.CompressionProviders),
+            options
+        );
     }
 
     // Async methods moved to GZipEntry.Async.cs

src/SharpCompress/Common/GZip/GZipFilePart.Async.cs

@@ -15,16 +15,7 @@ internal sealed partial class GZipFilePart
     internal static async ValueTask<GZipFilePart> CreateAsync(
         Stream stream,
         IArchiveEncoding archiveEncoding,
-        CancellationToken cancellationToken = default
-    )
-    {
-        return await CreateAsync(stream, archiveEncoding, null, cancellationToken);
-    }
-
-    internal static async ValueTask<GZipFilePart> CreateAsync(
-        Stream stream,
-        IArchiveEncoding archiveEncoding,
-        CompressionProviderRegistry? compressionProviders,
+        CompressionProviderRegistry compressionProviders,
         CancellationToken cancellationToken = default
     )
     {

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -12,34 +12,12 @@ internal sealed partial class GZipFilePart : FilePart
 {
     private string? _name;
     private readonly Stream _stream;
-    private readonly CompressionProviderRegistry? _compressionProviders;
-
-    internal static GZipFilePart Create(Stream stream, IArchiveEncoding archiveEncoding)
-    {
-        var part = new GZipFilePart(stream, archiveEncoding, null);
-
-        part.ReadAndValidateGzipHeader();
-        if (stream.CanSeek)
-        {
-            var position = stream.Position;
-            stream.Position = stream.Length - 8;
-            part.ReadTrailer();
-            stream.Position = position;
-            part.EntryStartPosition = position;
-        }
-        else
-        {
-            // For non-seekable streams, we can't read the trailer or track position.
-            // Set to 0 since the stream will be read sequentially from its current position.
-            part.EntryStartPosition = 0;
-        }
-        return part;
-    }
+    private readonly CompressionProviderRegistry _compressionProviders;
 
     internal static GZipFilePart Create(
         Stream stream,
         IArchiveEncoding archiveEncoding,
-        CompressionProviderRegistry? compressionProviders
+        CompressionProviderRegistry compressionProviders
     )
     {
         var part = new GZipFilePart(stream, archiveEncoding, compressionProviders);
@@ -62,13 +40,10 @@ internal sealed partial class GZipFilePart : FilePart
         return part;
     }
 
-    private GZipFilePart(Stream stream, IArchiveEncoding archiveEncoding)
-        : base(archiveEncoding) => _stream = stream;
-
     private GZipFilePart(
         Stream stream,
         IArchiveEncoding archiveEncoding,
-        CompressionProviderRegistry? compressionProviders
+        CompressionProviderRegistry compressionProviders
     )
         : base(archiveEncoding)
     {
@@ -86,8 +61,7 @@ internal sealed partial class GZipFilePart : FilePart
 
     internal override Stream GetCompressedStream()
     {
-        var providers = _compressionProviders ?? CompressionProviderRegistry.Default;
-        return providers.CreateDecompressStream(CompressionType.Deflate, _stream);
+        return _compressionProviders.CreateDecompressStream(CompressionType.Deflate, _stream);
     }
 
     internal override Stream GetRawStream() => _stream;

src/SharpCompress/Common/Options/IReaderOptions.cs

@@ -39,9 +39,9 @@ public interface IReaderOptions
     int? RewindableBufferSize { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom providers.
     /// Use this to provide alternative decompression implementations.
     /// </summary>
-    CompressionProviderRegistry? CompressionProviders { get; init; }
+    CompressionProviderRegistry CompressionProviders { get; init; }
 }

src/SharpCompress/Common/Options/IWriterOptions.cs

@@ -19,10 +19,9 @@ public interface IWriterOptions : IStreamOptions, IEncodingOptions, IProgressOpt
     int CompressionLevel { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative compression implementations, such as
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom providers, such as
     /// System.IO.Compression for Deflate/GZip on modern .NET.
     /// </summary>
-    CompressionProviderRegistry? CompressionProviders { get; init; }
+    CompressionProviderRegistry CompressionProviders { get; init; }
 }

src/SharpCompress/Common/Zip/SeekableZipFilePart.cs

@@ -9,18 +9,11 @@ internal partial class SeekableZipFilePart : ZipFilePart
     private bool _isLocalHeaderLoaded;
     private readonly SeekableZipHeaderFactory _headerFactory;
 
-    internal SeekableZipFilePart(
-        SeekableZipHeaderFactory headerFactory,
-        DirectoryEntryHeader header,
-        Stream stream
-    )
-        : base(header, stream) => _headerFactory = headerFactory;
-
     internal SeekableZipFilePart(
         SeekableZipHeaderFactory headerFactory,
         DirectoryEntryHeader header,
         Stream stream,
-        CompressionProviderRegistry? compressionProviders
+        CompressionProviderRegistry compressionProviders
     )
         : base(header, stream, compressionProviders) => _headerFactory = headerFactory;
 

src/SharpCompress/Common/Zip/StreamingZipFilePart.cs

@@ -9,13 +9,10 @@ internal sealed partial class StreamingZipFilePart : ZipFilePart
 {
     private Stream? _decompressionStream;
 
-    internal StreamingZipFilePart(ZipFileEntry header, Stream stream)
-        : base(header, stream) { }
-
     internal StreamingZipFilePart(
         ZipFileEntry header,
         Stream stream,
-        CompressionProviderRegistry? compressionProviders
+        CompressionProviderRegistry compressionProviders
     )
         : base(header, stream, compressionProviders) { }
 

src/SharpCompress/Common/Zip/ZipFilePart.cs

@@ -20,39 +20,24 @@ namespace SharpCompress.Common.Zip;
 
 internal abstract partial class ZipFilePart : FilePart
 {
-    private CompressionProviderRegistry? _compressionProviders;
+    private readonly CompressionProviderRegistry _compressionProviders;
 
-    internal ZipFilePart(ZipFileEntry header, Stream stream)
+    internal ZipFilePart(
+        ZipFileEntry header,
+        Stream stream,
+        CompressionProviderRegistry compressionProviders
+    )
         : base(header.ArchiveEncoding)
     {
         Header = header;
         header.Part = this;
         BaseStream = stream;
-    }
-
-    internal ZipFilePart(
-        ZipFileEntry header,
-        Stream stream,
-        CompressionProviderRegistry? compressionProviders
-    )
-        : this(header, stream)
-    {
         _compressionProviders = compressionProviders;
     }
 
     internal Stream BaseStream { get; }
     internal ZipFileEntry Header { get; set; }
 
-    /// <summary>
-    /// Gets or sets the compression provider registry.
-    /// If null, uses the default registry.
-    /// </summary>
-    internal CompressionProviderRegistry? CompressionProviders
-    {
-        get => _compressionProviders;
-        set => _compressionProviders = value;
-    }
-
     internal override string? FilePartName => Header.Name;
 
     internal override Stream GetCompressedStream()
@@ -89,8 +74,7 @@ internal abstract partial class ZipFilePart : FilePart
     /// <summary>
     /// Gets the compression provider registry, falling back to default if not set.
     /// </summary>
-    protected CompressionProviderRegistry GetProviders() =>
-        _compressionProviders ?? CompressionProviderRegistry.Default;
+    protected CompressionProviderRegistry GetProviders() => _compressionProviders;
 
     /// <summary>
     /// Converts ZipCompressionMethod to CompressionType.

src/SharpCompress/Readers/ReaderOptions.cs

@@ -149,12 +149,13 @@ public sealed record ReaderOptions : IReaderOptions
     /// The default handler logs a warning message.
     /// </remarks>
     public Action<string, string>? SymbolicLinkHandler { get; init; }
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative decompression implementations, such as
+
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom implementations, such as
     /// System.IO.Compression for Deflate/GZip on modern .NET.
     /// </summary>
-    public CompressionProviderRegistry? CompressionProviders { get; init; }
+    public CompressionProviderRegistry CompressionProviders { get; init; } =
+        CompressionProviderRegistry.Default;
 
     /// <summary>
     /// Creates a new ReaderOptions instance with default values.

src/SharpCompress/Readers/Tar/TarReader.cs

@@ -33,8 +33,7 @@ public partial class TarReader : AbstractReader<TarEntry, TarVolume>
     {
         var stream = base.RequestInitialStream();
 
-        // Get compression providers from options, falling back to default
-        var providers = Options.CompressionProviders ?? CompressionProviderRegistry.Default;
+        var providers = Options.CompressionProviders;
 
         return compressionType switch
         {

src/SharpCompress/Readers/Zip/ZipReader.Async.cs

@@ -21,24 +21,21 @@ public partial class ZipReader
         private readonly StreamingZipHeaderFactory _headerFactory;
         private readonly Stream _stream;
         private readonly IReaderOptions _options;
-        private readonly CompressionProviderRegistry? _compressionProviders;
 
         public ZipEntryAsyncEnumerable(
             StreamingZipHeaderFactory headerFactory,
             Stream stream,
-            IReaderOptions options,
-            CompressionProviderRegistry? compressionProviders
+            IReaderOptions options
         )
         {
             _headerFactory = headerFactory;
             _stream = stream;
             _options = options;
-            _compressionProviders = compressionProviders;
         }
 
         public IAsyncEnumerator<ZipEntry> GetAsyncEnumerator(
             CancellationToken cancellationToken = default
-        ) => new ZipEntryAsyncEnumerator(_headerFactory, _stream, _options, _compressionProviders, cancellationToken);
+        ) => new ZipEntryAsyncEnumerator(_headerFactory, _stream, _options, cancellationToken);
     }
 
     /// <summary>
@@ -49,20 +46,17 @@ public partial class ZipReader
         private readonly Stream _stream;
         private readonly IAsyncEnumerator<ZipHeader> _headerEnumerator;
         private readonly IReaderOptions _options;
-        private readonly CompressionProviderRegistry? _compressionProviders;
         private ZipEntry? _current;
 
         public ZipEntryAsyncEnumerator(
             StreamingZipHeaderFactory headerFactory,
             Stream stream,
             IReaderOptions options,
-            CompressionProviderRegistry? compressionProviders,
             CancellationToken cancellationToken
         )
         {
             _stream = stream;
             _options = options;
-            _compressionProviders = compressionProviders;
             _headerEnumerator = headerFactory
                 .ReadStreamHeaderAsync(stream)
                 .GetAsyncEnumerator(cancellationToken);
@@ -84,7 +78,11 @@ public partial class ZipReader
                 {
                     case ZipHeaderType.LocalEntry:
                         _current = new ZipEntry(
-                            new StreamingZipFilePart((LocalEntryHeader)header, _stream),
+                            new StreamingZipFilePart(
+                                (LocalEntryHeader)header,
+                                _stream,
+                                _options.CompressionProviders
+                            ),
                             _options
                         );
                         return true;

src/SharpCompress/Readers/Zip/ZipReader.cs

@@ -74,7 +74,11 @@ public partial class ZipReader : AbstractReader<ZipEntry, ZipVolume>
                     case ZipHeaderType.LocalEntry:
                         {
                             yield return new ZipEntry(
-                                new StreamingZipFilePart((LocalEntryHeader)h, stream),
+                                new StreamingZipFilePart(
+                                    (LocalEntryHeader)h,
+                                    stream,
+                                    Options.CompressionProviders
+                                ),
                                 Options
                             );
                         }
@@ -100,7 +104,7 @@ public partial class ZipReader : AbstractReader<ZipEntry, ZipVolume>
     /// Returns entries asynchronously for streams that only support async reads.
     /// </summary>
     protected override IAsyncEnumerable<ZipEntry> GetEntriesAsync(Stream stream) =>
-        new ZipEntryAsyncEnumerable(_headerFactory, stream, Options, Options.CompressionProviders);
+        new ZipEntryAsyncEnumerable(_headerFactory, stream, Options);
 
     // Async nested classes moved to ZipReader.Async.cs
 }

src/SharpCompress/Writers/GZip/GZipWriter.cs

@@ -19,14 +19,14 @@ public sealed partial class GZipWriter : AbstractWriter
             destination = SharpCompressStream.CreateNonDisposing(destination);
         }
 
-        // Get compression providers from options, falling back to default
-        var providers = options?.CompressionProviders ?? CompressionProviderRegistry.Default;
+        // Use the configured compression providers
+        var providers = WriterOptions.CompressionProviders;
 
         // Create the GZip stream using the provider
         var compressionStream = providers.CreateCompressStream(
             CompressionType.GZip,
             destination,
-            options?.CompressionLevel ?? (int)CompressionLevel.Default
+            WriterOptions.CompressionLevel
         );
 
         // If using internal GZipStream, set the encoding for header filename

src/SharpCompress/Writers/GZip/GZipWriterOptions.cs

@@ -68,12 +68,12 @@ public sealed record GZipWriterOptions : IWriterOptions
     public IProgress<ProgressReport>? Progress { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative compression implementations, such as
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom implementations, such as
     /// System.IO.Compression for GZip on modern .NET.
     /// </summary>
-    public CompressionProviderRegistry? CompressionProviders { get; init; }
+    public CompressionProviderRegistry CompressionProviders { get; init; } =
+        CompressionProviderRegistry.Default;
 
     /// <summary>
     /// Creates a new GZipWriterOptions instance with default values.
@@ -114,6 +114,7 @@ public sealed record GZipWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 
     /// <summary>
@@ -126,5 +127,6 @@ public sealed record GZipWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 }

src/SharpCompress/Writers/Tar/TarWriter.cs

@@ -29,8 +29,7 @@ public partial class TarWriter : AbstractWriter
             destination = SharpCompressStream.CreateNonDisposing(destination);
         }
 
-        // Get compression providers from options, falling back to default
-        var providers = options.CompressionProviders ?? CompressionProviderRegistry.Default;
+        var providers = options.CompressionProviders;
 
         destination = options.CompressionType switch
         {

src/SharpCompress/Writers/Tar/TarWriterOptions.cs

@@ -44,11 +44,11 @@ public sealed record TarWriterOptions : IWriterOptions
     public IProgress<ProgressReport>? Progress { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative compression implementations.
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom implementations.
     /// </summary>
-    public CompressionProviderRegistry? CompressionProviders { get; init; }
+    public CompressionProviderRegistry CompressionProviders { get; init; } =
+        CompressionProviderRegistry.Default;
 
     /// <summary>
     /// Indicates if archive should be finalized (by 2 empty blocks) on close.
@@ -104,6 +104,7 @@ public sealed record TarWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 
     /// <summary>
@@ -117,6 +118,7 @@ public sealed record TarWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 
     /// <summary>

src/SharpCompress/Writers/WriterOptions.cs

@@ -64,12 +64,12 @@ public sealed record WriterOptions : IWriterOptions
     public IProgress<ProgressReport>? Progress { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative compression implementations, such as
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom implementations, such as
     /// System.IO.Compression for Deflate/GZip on modern .NET.
     /// </summary>
-    public CompressionProviderRegistry? CompressionProviders { get; init; }
+    public CompressionProviderRegistry CompressionProviders { get; init; } =
+        CompressionProviderRegistry.Default;
 
     /// <summary>
     /// Creates a new WriterOptions instance with the specified compression type.

src/SharpCompress/Writers/Zip/ZipWriter.cs

@@ -421,9 +421,7 @@ public partial class ZipWriter : AbstractWriter
             counting = new CountingStream(SharpCompressStream.CreateNonDisposing(writeStream));
             Stream output = counting;
 
-            // Get compression providers from writer options, falling back to default
-            var providers =
-                writer.WriterOptions.CompressionProviders ?? CompressionProviderRegistry.Default;
+            var providers = writer.WriterOptions.CompressionProviders;
 
             switch (zipCompressionMethod)
             {

src/SharpCompress/Writers/Zip/ZipWriterOptions.cs

@@ -61,11 +61,11 @@ public sealed record ZipWriterOptions : IWriterOptions
     public IProgress<ProgressReport>? Progress { get; init; }
 
     /// <summary>
-    /// Optional registry of compression providers.
-    /// If null, the default registry (SharpCompress internal implementations) will be used.
-    /// Use this to provide alternative compression implementations.
+    /// Registry of compression providers.
+    /// Defaults to <see cref="CompressionProviderRegistry.Default" /> but can be replaced with custom implementations.
     /// </summary>
-    public CompressionProviderRegistry? CompressionProviders { get; init; }
+    public CompressionProviderRegistry CompressionProviders { get; init; } =
+        CompressionProviderRegistry.Default;
 
     /// <summary>
     /// Optional comment for the archive.
@@ -127,6 +127,7 @@ public sealed record ZipWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 
     /// <summary>
@@ -139,6 +140,7 @@ public sealed record ZipWriterOptions : IWriterOptions
         LeaveStreamOpen = options.LeaveStreamOpen;
         ArchiveEncoding = options.ArchiveEncoding;
         Progress = options.Progress;
+        CompressionProviders = options.CompressionProviders;
     }
 
     /// <summary>

tests/SharpCompress.Test/CompressionProviderTests.cs

@@ -134,13 +134,10 @@ public class CompressionProviderTests
     }
 
     [Fact]
-    public void TarWriter_WithNullProvider_UsesDefault()
+    public void TarWriter_WithoutCustomProvider_UsesDefault()
     {
         using var stream = new MemoryStream();
-        var options = new TarWriterOptions(CompressionType.GZip, true)
-        {
-            CompressionProviders = null, // Should use default
-        };
+        var options = new TarWriterOptions(CompressionType.GZip, true);
 
         using (var writer = new TarWriter(stream, options))
         {