Add opt-in multi-threading support with SupportsMultiThreadedExtraction flag

- Added IArchive.SupportsMultiThreadedExtraction property to indicate if multi-threading is supported
- Added ReaderOptions.EnableMultiThreadedExtraction option to opt-in to multi-threading
- Updated SeekableZipFilePart, TarFilePart, and SeekableFilePart to check the flag
- Added test to verify multi-threading flag behavior
- Multi-threading is now disabled by default for backward compatibility

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>

.editorconfig

@@ -307,7 +307,6 @@ dotnet_diagnostic.CS8602.severity = error
 dotnet_diagnostic.CS8604.severity = error
 dotnet_diagnostic.CS8618.severity = error
 dotnet_diagnostic.CS0618.severity = suggestion
-dotnet_diagnostic.CS1998.severity = error
 dotnet_diagnostic.CS4014.severity = error
 dotnet_diagnostic.CS8600.severity = error
 dotnet_diagnostic.CS8603.severity = error

.gitignore

@@ -4,8 +4,8 @@ _ReSharper.SharpCompress/
 bin/
 *.suo
 *.user
-TestArchives/Scratch/
-TestArchives/Scratch2/
+tests/TestArchives/Scratch/
+tests/TestArchives/Scratch2/
 TestResults/
 *.nupkg
 packages/*/

AGENTS.md

@@ -14,6 +14,7 @@ SharpCompress is a pure C# compression library supporting multiple archive forma
 - Follow the existing code style and patterns in the codebase.
 
 ## General Instructions
+- **Agents should NEVER commit to git** - Agents should stage files and leave committing to the user. Only create commits when the user explicitly requests them.
 - Make only high confidence suggestions when reviewing code changes.
 - Write code with good maintainability practices, including comments on why certain design decisions were made.
 - Handle edge cases and write clear exception handling.
@@ -110,7 +111,7 @@ SharpCompress supports multiple archive and compression formats:
 - **Archive Formats**: Zip, Tar, 7Zip, Rar (read-only)
 - **Compression**: DEFLATE, BZip2, LZMA/LZMA2, PPMd, ZStandard (decompress only), Deflate64 (decompress only)
 - **Combined Formats**: Tar.GZip, Tar.BZip2, Tar.LZip, Tar.XZ, Tar.ZStandard
-- See FORMATS.md for complete format support matrix
+- See [docs/FORMATS.md](docs/FORMATS.md) for complete format support matrix
 
 ### Stream Handling Rules
 - **Disposal**: As of version 0.21, SharpCompress closes wrapped streams by default
@@ -177,5 +178,4 @@ SharpCompress supports multiple archive and compression formats:
 2. **Solid archives (Rar, 7Zip)** - Use `ExtractAllEntries()` for best performance, not individual entry extraction
 3. **Stream disposal** - Always set `LeaveStreamOpen` explicitly when needed (default is to close)
 4. **Tar + non-seekable stream** - Must provide file size or it will throw
-5. **Multi-framework differences** - Some features differ between .NET Framework and modern .NET (e.g., Mono.Posix)
 6. **Format detection** - Use `ReaderFactory.Open()` for auto-detection, test with actual archive files

Directory.Build.props

@@ -12,5 +12,6 @@
     <RunAnalyzersDuringBuild>False</RunAnalyzersDuringBuild>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
+    <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
   </PropertyGroup>
 </Project>

Directory.Packages.props

@@ -5,6 +5,7 @@
     <PackageVersion Include="Glob" Version="1.1.9" />
     <PackageVersion Include="JetBrains.Profiler.SelfApi" Version="2.5.15" />
     <PackageVersion Include="Microsoft.Bcl.AsyncInterfaces" Version="10.0.0" />
+    <PackageVersion Include="Microsoft.NET.ILLink.Task" Version="10.0.0" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageVersion Include="Mono.Posix.NETStandard" Version="1.0.0" />
     <PackageVersion Include="SimpleExec" Version="13.0.0" />

README.md

@@ -4,7 +4,7 @@ SharpCompress is a compression library in pure C# for .NET Framework 4.8, .NET 8
 
 The major feature is support for non-seekable streams so large files can be processed on the fly (i.e. download stream).
 
-**NEW:** All I/O operations now support async/await for improved performance and scalability. See the [USAGE.md](USAGE.md#async-examples) for examples.
+**NEW:** All I/O operations now support async/await for improved performance and scalability. See the [USAGE.md](docs/USAGE.md#async-examples) for examples.
 
 GitHub Actions Build -
 [![SharpCompress](https://github.com/adamhathcock/sharpcompress/actions/workflows/dotnetcore.yml/badge.svg)](https://github.com/adamhathcock/sharpcompress/actions/workflows/dotnetcore.yml)
@@ -14,7 +14,7 @@ GitHub Actions Build -
 
 Post Issues on Github!
 
-Check the [Supported Formats](FORMATS.md) and [Basic Usage.](USAGE.md)
+Check the [Supported Formats](docs/FORMATS.md) and [Basic Usage.](docs/USAGE.md)
 
 ## Recommended Formats
 

SharpCompress.sln

@@ -18,12 +18,11 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Config", "Config", "{CDB425
 		Directory.Build.props = Directory.Build.props
 		global.json = global.json
 		.editorconfig = .editorconfig
+		.gitignore = .gitignore
 		Directory.Packages.props = Directory.Packages.props
 		NuGet.config = NuGet.config
 		.github\workflows\nuget-release.yml = .github\workflows\nuget-release.yml
-		USAGE.md = USAGE.md
 		README.md = README.md
-		FORMATS.md = FORMATS.md
 		AGENTS.md = AGENTS.md
 	EndProjectSection
 EndProject

docs/API.md

@@ -0,0 +1,512 @@
+# API Quick Reference
+
+Quick reference for commonly used SharpCompress APIs.
+
+## Factory Methods
+
+### Opening Archives
+
+```csharp
+// Auto-detect format
+using (var reader = ReaderFactory.OpenReader(stream))
+{
+    // Works with Zip, Tar, GZip, Rar, 7Zip, etc.
+}
+
+// Specific format - Archive API
+using (var archive = ZipArchive.OpenArchive("file.zip"))
+using (var archive = TarArchive.OpenArchive("file.tar"))
+using (var archive = RarArchive.OpenArchive("file.rar"))
+using (var archive = SevenZipArchive.OpenArchive("file.7z"))
+using (var archive = GZipArchive.OpenArchive("file.gz"))
+
+// With options
+var options = new ReaderOptions
+{
+    Password = "password",
+    LeaveStreamOpen = true,
+    ArchiveEncoding = new ArchiveEncoding { Default = Encoding.GetEncoding(932) }
+};
+using (var archive = ZipArchive.OpenArchive("encrypted.zip", options))
+```
+
+### Creating Archives
+
+```csharp
+// Writer Factory
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Zip, CompressionType.Deflate))
+{
+    // Write entries
+}
+
+// Specific writer
+using (var archive = ZipArchive.CreateArchive())
+using (var archive = TarArchive.CreateArchive())
+using (var archive = GZipArchive.CreateArchive())
+
+// With options
+var options = new WriterOptions(CompressionType.Deflate)
+{
+    CompressionLevel = 9,
+    LeaveStreamOpen = false
+};
+using (var archive = ZipArchive.CreateArchive())
+{
+    archive.SaveTo("output.zip", options);
+}
+```
+
+---
+
+## Archive API Methods
+
+### Reading/Extracting
+
+```csharp
+using (var archive = ZipArchive.OpenArchive("file.zip"))
+{
+    // Get all entries
+    IEnumerable<IArchiveEntry> entries = archive.Entries;
+
+    // Find specific entry
+    var entry = archive.Entries.FirstOrDefault(e => e.Key == "file.txt");
+
+    // Extract all
+    archive.WriteToDirectory(@"C:\output", new ExtractionOptions
+    {
+        ExtractFullPath = true,
+        Overwrite = true
+    });
+
+    // Extract single entry
+    var entry = archive.Entries.First();
+    entry.WriteToFile(@"C:\output\file.txt");
+    entry.WriteToFile(@"C:\output\file.txt", new ExtractionOptions { Overwrite = true });
+
+    // Get entry stream
+    using (var stream = entry.OpenEntryStream())
+    {
+        stream.CopyTo(outputStream);
+    }
+}
+
+// Async extraction (requires IAsyncArchive)
+using (var asyncArchive = await ZipArchive.OpenAsyncArchive("file.zip"))
+{
+    await asyncArchive.WriteToDirectoryAsync(
+        @"C:\output",
+        new ExtractionOptions { ExtractFullPath = true, Overwrite = true },
+        cancellationToken: cancellationToken
+    );
+}
+using (var stream = await entry.OpenEntryStreamAsync(cancellationToken))
+{
+    // ...
+}
+```
+
+### Entry Properties
+
+```csharp
+foreach (var entry in archive.Entries)
+{
+    string name = entry.Key;              // Entry name/path
+    long size = entry.Size;               // Uncompressed size
+    long compressedSize = entry.CompressedSize;
+    bool isDir = entry.IsDirectory;
+    DateTime? modTime = entry.LastModifiedTime;
+    CompressionType compression = entry.CompressionType;
+}
+```
+
+### Creating Archives
+
+```csharp
+using (var archive = ZipArchive.CreateArchive())
+{
+    // Add file
+    archive.AddEntry("file.txt", @"C:\source\file.txt");
+
+    // Add multiple files
+    archive.AddAllFromDirectory(@"C:\source");
+    archive.AddAllFromDirectory(@"C:\source", "*.txt");  // Pattern
+
+    // Save to file
+    archive.SaveTo("output.zip", CompressionType.Deflate);
+
+    // Save to stream
+    archive.SaveTo(outputStream, new WriterOptions(CompressionType.Deflate)
+    {
+        CompressionLevel = 9,
+        LeaveStreamOpen = true
+    });
+}
+```
+
+---
+
+## Reader API Methods
+
+### Forward-Only Reading
+
+```csharp
+using (var stream = File.OpenRead("file.zip"))
+using (var reader = ReaderFactory.OpenReader(stream))
+{
+    while (reader.MoveToNextEntry())
+    {
+        IArchiveEntry entry = reader.Entry;
+
+        if (!entry.IsDirectory)
+        {
+            // Extract entry
+            reader.WriteEntryToDirectory(@"C:\output");
+            reader.WriteEntryToFile(@"C:\output\file.txt");
+
+            // Or get stream
+            using (var entryStream = reader.OpenEntryStream())
+            {
+                entryStream.CopyTo(outputStream);
+            }
+        }
+    }
+}
+
+// Async variants (use OpenAsyncReader to get IAsyncReader)
+using (var stream = File.OpenRead("file.zip"))
+using (var reader = await ReaderFactory.OpenAsyncReader(stream))
+{
+    while (await reader.MoveToNextEntryAsync())
+    {
+        await reader.WriteEntryToFileAsync(
+            @"C:\output\" + reader.Entry.Key,
+            cancellationToken: cancellationToken
+        );
+    }
+
+    // Async extraction of all entries
+    await reader.WriteAllToDirectoryAsync(
+        @"C:\output",
+        new ExtractionOptions { ExtractFullPath = true, Overwrite = true },
+        cancellationToken
+    );
+}
+```
+
+---
+
+## Writer API Methods
+
+### Creating Archives (Streaming)
+
+```csharp
+using (var stream = File.Create("output.zip"))
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Zip, CompressionType.Deflate))
+{
+    // Write single file
+    using (var fileStream = File.OpenRead("source.txt"))
+    {
+        writer.Write("entry.txt", fileStream, DateTime.Now);
+    }
+    
+    // Write directory
+    writer.WriteAll("C:\\source", "*", SearchOption.AllDirectories);
+    writer.WriteAll("C:\\source", "*.txt", SearchOption.TopDirectoryOnly);
+    
+    // Async variants
+    using (var fileStream = File.OpenRead("source.txt"))
+    {
+        await writer.WriteAsync("entry.txt", fileStream, DateTime.Now, cancellationToken);
+    }
+    
+    await writer.WriteAllAsync("C:\\source", "*", SearchOption.AllDirectories, cancellationToken);
+}
+```
+
+---
+
+## Common Options
+
+### ReaderOptions
+
+```csharp
+var options = new ReaderOptions
+{
+    Password = "password",                          // For encrypted archives
+    LeaveStreamOpen = true,                         // Don't close wrapped stream
+    ArchiveEncoding = new ArchiveEncoding          // Custom character encoding
+    {
+        Default = Encoding.GetEncoding(932)
+    }
+};
+using (var archive = ZipArchive.OpenArchive("file.zip", options))
+{
+    // ...
+}
+```
+
+### WriterOptions
+
+```csharp
+var options = new WriterOptions(CompressionType.Deflate)
+{
+    CompressionLevel = 9,                           // 0-9 for Deflate
+    LeaveStreamOpen = true,                         // Don't close stream
+};
+archive.SaveTo("output.zip", options);
+```
+
+### ExtractionOptions
+
+```csharp
+var options = new ExtractionOptions
+{
+    ExtractFullPath = true,                         // Recreate directory structure
+    Overwrite = true,                               // Overwrite existing files
+    PreserveFileTime = true                         // Keep original timestamps
+};
+archive.WriteToDirectory(@"C:\output", options);
+```
+
+---
+
+## Compression Types
+
+### Available Compressions
+
+```csharp
+// For creating archives
+CompressionType.None       // No compression (store)
+CompressionType.Deflate    // DEFLATE (default for ZIP/GZip)
+CompressionType.Deflate64  // Deflate64
+CompressionType.BZip2      // BZip2
+CompressionType.LZMA       // LZMA (for 7Zip, LZip, XZ)
+CompressionType.PPMd       // PPMd (for ZIP)
+CompressionType.Rar        // RAR compression (read-only)
+CompressionType.ZStandard  // ZStandard
+ArchiveType.Arc
+ArchiveType.Arj
+ArchiveType.Ace
+
+// For Tar archives with compression
+// Use WriterFactory to create compressed tar archives
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Tar, CompressionType.GZip))  // Tar.GZip
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Tar, CompressionType.BZip2)) // Tar.BZip2
+```
+
+### Archive Types
+
+```csharp
+ArchiveType.Zip
+ArchiveType.Tar
+ArchiveType.GZip
+ArchiveType.BZip2
+ArchiveType.Rar
+ArchiveType.SevenZip
+ArchiveType.XZ
+ArchiveType.ZStandard
+```
+
+---
+
+## Patterns & Examples
+
+### Extract with Error Handling
+
+```csharp
+try
+{
+    using (var archive = ZipArchive.Open("archive.zip", 
+        new ReaderOptions { Password = "password" }))
+    {
+        archive.WriteToDirectory(@"C:\output", new ExtractionOptions
+        {
+            ExtractFullPath = true,
+            Overwrite = true
+        });
+    }
+}
+catch (PasswordRequiredException)
+{
+    Console.WriteLine("Password required");
+}
+catch (InvalidArchiveException)
+{
+    Console.WriteLine("Archive is invalid");
+}
+catch (SharpCompressException ex)
+{
+    Console.WriteLine($"Error: {ex.Message}");
+}
+```
+
+### Extract with Progress
+
+```csharp
+var progress = new Progress<ProgressReport>(report =>
+{
+    Console.WriteLine($"Extracting {report.EntryPath}: {report.PercentComplete}%");
+});
+
+var options = new ReaderOptions { Progress = progress };
+using (var archive = ZipArchive.OpenArchive("archive.zip", options))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+```
+
+### Async Extract with Cancellation
+
+```csharp
+var cts = new CancellationTokenSource();
+cts.CancelAfter(TimeSpan.FromMinutes(5));
+
+try
+{
+    using (var archive = await ZipArchive.OpenAsyncArchive("archive.zip"))
+    {
+        await archive.WriteToDirectoryAsync(
+            @"C:\output",
+            new ExtractionOptions { ExtractFullPath = true, Overwrite = true },
+            cancellationToken: cts.Token
+        );
+    }
+}
+catch (OperationCanceledException)
+{
+    Console.WriteLine("Extraction cancelled");
+}
+```
+
+### Create with Custom Compression
+
+```csharp
+using (var archive = ZipArchive.CreateArchive())
+{
+    archive.AddAllFromDirectory(@"D:\source");
+    
+    // Fastest
+    archive.SaveTo("fast.zip", new WriterOptions(CompressionType.Deflate)
+    {
+        CompressionLevel = 1
+    });
+    
+    // Balanced (default)
+    archive.SaveTo("normal.zip", CompressionType.Deflate);
+    
+    // Best compression
+    archive.SaveTo("best.zip", new WriterOptions(CompressionType.Deflate)
+    {
+        CompressionLevel = 9
+    });
+}
+```
+
+### Stream Processing (No File I/O)
+
+```csharp
+using (var outputStream = new MemoryStream())
+using (var archive = ZipArchive.CreateArchive())
+{
+    // Add content from memory
+    using (var contentStream = new MemoryStream(Encoding.UTF8.GetBytes("Hello")))
+    {
+        archive.AddEntry("file.txt", contentStream);
+    }
+    
+    // Save to memory
+    archive.SaveTo(outputStream, CompressionType.Deflate);
+    
+    // Get bytes
+    byte[] archiveBytes = outputStream.ToArray();
+}
+```
+
+### Extract Specific Files
+
+```csharp
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    var filesToExtract = new[] { "file1.txt", "file2.txt" };
+    
+    foreach (var entry in archive.Entries.Where(e => filesToExtract.Contains(e.Key)))
+    {
+        entry.WriteToFile(@"C:\output\" + entry.Key);
+    }
+}
+```
+
+### List Archive Contents
+
+```csharp
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    foreach (var entry in archive.Entries)
+    {
+        if (entry.IsDirectory)
+            Console.WriteLine($"[DIR]  {entry.Key}");
+        else
+            Console.WriteLine($"[FILE] {entry.Key} ({entry.Size} bytes)");
+    }
+}
+```
+
+---
+
+## Common Mistakes
+
+### ✗ Wrong - Stream not disposed
+
+```csharp
+var stream = File.OpenRead("archive.zip");
+var archive = ZipArchive.OpenArchive(stream);
+archive.WriteToDirectory(@"C:\output");
+// stream not disposed - leaked resource
+```
+
+### ✓ Correct - Using blocks
+
+```csharp
+using (var stream = File.OpenRead("archive.zip"))
+using (var archive = ZipArchive.OpenArchive(stream))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+// Both properly disposed
+```
+
+### ✗ Wrong - Mixing API styles
+
+```csharp
+// Loading entire archive then iterating
+using (var archive = ZipArchive.OpenArchive("large.zip"))
+{
+    var entries = archive.Entries.ToList();  // Loads all in memory
+    foreach (var e in entries)
+    {
+        e.WriteToFile(...);  // Then extracts each
+    }
+}
+```
+
+### ✓ Correct - Use Reader for large files
+
+```csharp
+// Streaming iteration
+using (var stream = File.OpenRead("large.zip"))
+using (var reader = ReaderFactory.OpenReader(stream))
+{
+    while (reader.MoveToNextEntry())
+    {
+        reader.WriteEntryToDirectory(@"C:\output");
+    }
+}
+```
+
+---
+
+## Related Documentation
+
+- [USAGE.md](USAGE.md) - Complete code examples
+- [FORMATS.md](FORMATS.md) - Supported formats
+- [PERFORMANCE.md](PERFORMANCE.md) - API selection guide

docs/ARCHITECTURE.md

@@ -0,0 +1,659 @@
+# SharpCompress Architecture Guide
+
+This guide explains the internal architecture and design patterns of SharpCompress for contributors.
+
+## Overview
+
+SharpCompress is organized into three main layers:
+
+```
+┌─────────────────────────────────────────┐
+│     User-Facing APIs (Top Layer)        │
+│  Archive, Reader, Writer Factories      │
+├─────────────────────────────────────────┤
+│     Format-Specific Implementations     │
+│  ZipArchive, TarReader, GZipWriter,     │
+│  RarArchive, SevenZipArchive, etc.      │
+├─────────────────────────────────────────┤
+│     Compression & Crypto (Bottom Layer) │
+│  Deflate, LZMA, BZip2, AES, CRC32       │
+└─────────────────────────────────────────┘
+```
+
+---
+
+## Directory Structure
+
+### `src/SharpCompress/`
+
+#### `Archives/` - Archive Implementations
+Contains `IArchive` implementations for seekable, random-access APIs.
+
+**Key Files:**
+- `AbstractArchive.cs` - Base class for all archives
+- `IArchive.cs` - Archive interface definition
+- `ArchiveFactory.cs` - Factory for opening archives
+- Format-specific: `ZipArchive.cs`, `TarArchive.cs`, `RarArchive.cs`, `SevenZipArchive.cs`, `GZipArchive.cs`
+
+**Use Archive API when:**
+- Stream is seekable (file, memory)
+- Need random access to entries
+- Archive fits in memory
+- Simplicity is important
+
+#### `Readers/` - Reader Implementations
+Contains `IReader` implementations for forward-only, non-seekable APIs.
+
+**Key Files:**
+- `AbstractReader.cs` - Base reader class
+- `IReader.cs` - Reader interface
+- `ReaderFactory.cs` - Auto-detection factory
+- `ReaderOptions.cs` - Configuration for readers
+- Format-specific: `ZipReader.cs`, `TarReader.cs`, `GZipReader.cs`, `RarReader.cs`, etc.
+
+**Use Reader API when:**
+- Stream is non-seekable (network, pipe, compressed)
+- Processing large files
+- Memory is limited
+- Forward-only processing is acceptable
+
+#### `Writers/` - Writer Implementations
+Contains `IWriter` implementations for forward-only writing.
+
+**Key Files:**
+- `AbstractWriter.cs` - Base writer class
+- `IWriter.cs` - Writer interface
+- `WriterFactory.cs` - Factory for creating writers
+- `WriterOptions.cs` - Configuration for writers
+- Format-specific: `ZipWriter.cs`, `TarWriter.cs`, `GZipWriter.cs`
+
+#### `Factories/` - Format Detection
+Factory classes for auto-detecting archive format and creating appropriate readers/writers.
+
+**Key Files:**
+- `Factory.cs` - Base factory class
+- `IFactory.cs` - Factory interface
+- Format-specific: `ZipFactory.cs`, `TarFactory.cs`, `RarFactory.cs`, etc.
+
+**How It Works:**
+1. `ReaderFactory.OpenReader(stream)` probes stream signatures
+2. Identifies format by magic bytes
+3. Creates appropriate reader instance
+4. Returns generic `IReader` interface
+
+#### `Common/` - Shared Types
+Common types, options, and enumerations used across formats.
+
+**Key Files:**
+- `IEntry.cs` - Entry interface (file within archive)
+- `Entry.cs` - Entry implementation
+- `ArchiveType.cs` - Enum for archive formats
+- `CompressionType.cs` - Enum for compression methods
+- `ArchiveEncoding.cs` - Character encoding configuration
+- `ExtractionOptions.cs` - Extraction configuration
+- Format-specific headers: `Zip/Headers/`, `Tar/Headers/`, `Rar/Headers/`, etc.
+
+#### `Compressors/` - Compression Algorithms
+Low-level compression streams implementing specific algorithms.
+
+**Algorithms:**
+- `Deflate/` - DEFLATE compression (Zip default)
+- `BZip2/` - BZip2 compression
+- `LZMA/` - LZMA compression (7Zip, XZ, LZip)
+- `PPMd/` - Prediction by Partial Matching (Zip, 7Zip)
+- `ZStandard/` - ZStandard compression (decompression only)
+- `Xz/` - XZ format (decompression only)
+- `Rar/` - RAR-specific unpacking
+- `Arj/`, `Arc/`, `Ace/` - Legacy format decompression
+- `Filters/` - BCJ/BCJ2 filters for executable compression
+
+**Each Compressor:**
+- Implements a `Stream` subclass
+- Provides both compression and decompression
+- Some are read-only (decompression only)
+
+#### `Crypto/` - Encryption & Hashing
+Cryptographic functions and stream wrappers.
+
+**Key Files:**
+- `Crc32Stream.cs` - CRC32 calculation wrapper
+- `BlockTransformer.cs` - Block cipher transformations
+- AES, PKWare, WinZip encryption implementations
+
+#### `IO/` - Stream Utilities
+Stream wrappers and utilities.
+
+**Key Classes:**
+- `SharpCompressStream` - Base stream class
+- `ProgressReportingStream` - Progress tracking wrapper
+- `MarkingBinaryReader` - Binary reader with position marks
+- `BufferedSubStream` - Buffered read-only substream
+- `ReadOnlySubStream` - Read-only view of parent stream
+- `NonDisposingStream` - Prevents wrapped stream disposal
+
+---
+
+## Design Patterns
+
+### 1. Factory Pattern
+
+**Purpose:** Auto-detect format and create appropriate reader/writer.
+
+**Example:**
+```csharp
+// User calls factory
+using (var reader = ReaderFactory.OpenReader(stream))  // Returns IReader
+{
+    while (reader.MoveToNextEntry())
+    {
+        // Process entry
+    }
+}
+
+// Behind the scenes:
+// 1. Factory.Open() probes stream signatures
+// 2. Detects format (Zip, Tar, Rar, etc.)
+// 3. Creates appropriate reader (ZipReader, TarReader, etc.)
+// 4. Returns as generic IReader interface
+```
+
+**Files:**
+- `src/SharpCompress/Factories/ReaderFactory.cs`
+- `src/SharpCompress/Factories/WriterFactory.cs`
+- `src/SharpCompress/Factories/ArchiveFactory.cs`
+
+### 2. Strategy Pattern
+
+**Purpose:** Encapsulate compression algorithms as swappable strategies.
+
+**Example:**
+```csharp
+// Different compression strategies
+CompressionType.Deflate     // DEFLATE
+CompressionType.BZip2       // BZip2
+CompressionType.LZMA        // LZMA
+CompressionType.PPMd        // PPMd
+
+// Writer uses strategy pattern
+var archive = ZipArchive.CreateArchive();
+archive.SaveTo("output.zip", CompressionType.Deflate);   // Use Deflate
+archive.SaveTo("output.bz2", CompressionType.BZip2);    // Use BZip2
+```
+
+**Files:**
+- `src/SharpCompress/Compressors/` - Strategy implementations
+
+### 3. Decorator Pattern
+
+**Purpose:** Wrap streams with additional functionality.
+
+**Example:**
+```csharp
+// Progress reporting decorator
+var progressStream = new ProgressReportingStream(baseStream, progressReporter);
+progressStream.Read(buffer, 0, buffer.Length);  // Reports progress
+
+// Non-disposing decorator
+var nonDisposingStream = new NonDisposingStream(baseStream);
+using (var compressor = new DeflateStream(nonDisposingStream))
+{
+    // baseStream won't be disposed when compressor is disposed
+}
+```
+
+**Files:**
+- `src/SharpCompress/IO/ProgressReportingStream.cs`
+- `src/SharpCompress/IO/NonDisposingStream.cs`
+
+### 4. Template Method Pattern
+
+**Purpose:** Define algorithm skeleton in base class, let subclasses fill details.
+
+**Example:**
+```csharp
+// AbstractArchive defines common archive operations
+public abstract class AbstractArchive : IArchive
+{
+    // Template methods
+    public virtual void WriteToDirectory(string destinationDirectory, ExtractionOptions options)
+    {
+        // Common extraction logic
+        foreach (var entry in Entries)
+        {
+            // Call subclass method
+            entry.WriteToFile(destinationPath, options);
+        }
+    }
+    
+    // Subclasses override format-specific details
+    protected abstract Entry CreateEntry(EntryData data);
+}
+```
+
+**Files:**
+- `src/SharpCompress/Archives/AbstractArchive.cs`
+- `src/SharpCompress/Readers/AbstractReader.cs`
+
+### 5. Iterator Pattern
+
+**Purpose:** Provide sequential access to entries.
+
+**Example:**
+```csharp
+// Archive API - provides collection
+IEnumerable<IEntry> entries = archive.Entries;
+foreach (var entry in entries)
+{
+    // Random access - entries already in memory
+}
+
+// Reader API - provides iterator
+IReader reader = ReaderFactory.OpenReader(stream);
+while (reader.MoveToNextEntry())
+{
+    // Forward-only iteration - one entry at a time
+    var entry = reader.Entry;
+}
+```
+
+---
+
+## Key Interfaces
+
+### IArchive - Random Access API
+
+```csharp
+public interface IArchive : IDisposable
+{
+    IEnumerable<IEntry> Entries { get; }
+    
+    void WriteToDirectory(string destinationDirectory, 
+                         ExtractionOptions options = null);
+    
+    IEntry FirstOrDefault(Func<IEntry, bool> predicate);
+    
+    // ... format-specific methods
+}
+```
+
+**Implementations:** `ZipArchive`, `TarArchive`, `RarArchive`, `SevenZipArchive`, `GZipArchive`
+
+### IReader - Forward-Only API
+
+```csharp
+public interface IReader : IDisposable
+{
+    IEntry Entry { get; }
+    
+    bool MoveToNextEntry();
+    
+    void WriteEntryToDirectory(string destinationDirectory,
+                              ExtractionOptions options = null);
+    
+    Stream OpenEntryStream();
+    
+    // ... async variants
+}
+```
+
+**Implementations:** `ZipReader`, `TarReader`, `RarReader`, `GZipReader`, etc.
+
+### IWriter - Writing API
+
+```csharp
+public interface IWriter : IDisposable
+{
+    void Write(string entryPath, Stream source, 
+              DateTime? modificationTime = null);
+    
+    void WriteAll(string sourceDirectory, string searchPattern,
+                 SearchOption searchOption);
+    
+    // ... async variants
+}
+```
+
+**Implementations:** `ZipWriter`, `TarWriter`, `GZipWriter`
+
+### IEntry - Archive Entry
+
+```csharp
+public interface IEntry
+{
+    string Key { get; }
+    uint Size { get; }
+    uint CompressedSize { get; }
+    bool IsDirectory { get; }
+    DateTime? LastModifiedTime { get; }
+    CompressionType CompressionType { get; }
+    
+    void WriteToFile(string fullPath, ExtractionOptions options = null);
+    void WriteToStream(Stream destinationStream);
+    Stream OpenEntryStream();
+    
+    // ... async variants
+}
+```
+
+---
+
+## Adding Support for a New Format
+
+### Step 1: Understand the Format
+- Research format specification
+- Understand compression/encryption used
+- Study existing similar formats in codebase
+
+### Step 2: Create Format Structure Classes
+
+**Create:** `src/SharpCompress/Common/NewFormat/`
+
+```csharp
+// Headers and data structures
+public class NewFormatHeader
+{
+    public uint Magic { get; set; }
+    public ushort Version { get; set; }
+    // ... other fields
+    
+    public static NewFormatHeader Read(BinaryReader reader)
+    {
+        // Deserialize from binary
+    }
+}
+
+public class NewFormatEntry
+{
+    public string FileName { get; set; }
+    public uint CompressedSize { get; set; }
+    public uint UncompressedSize { get; set; }
+    // ... other fields
+}
+```
+
+### Step 3: Create Archive Implementation
+
+**Create:** `src/SharpCompress/Archives/NewFormat/NewFormatArchive.cs`
+
+```csharp
+public class NewFormatArchive : AbstractArchive
+{
+    private NewFormatHeader _header;
+    private List<NewFormatEntry> _entries;
+    
+    public static NewFormatArchive OpenArchive(Stream stream)
+    {
+        var archive = new NewFormatArchive();
+        archive._header = NewFormatHeader.Read(stream);
+        archive.LoadEntries(stream);
+        return archive;
+    }
+    
+    public override IEnumerable<IEntry> Entries => _entries.Select(e => new Entry(e));
+    
+    protected override Stream OpenEntryStream(Entry entry)
+    {
+        // Return decompressed stream for entry
+    }
+    
+    // ... other abstract method implementations
+}
+```
+
+### Step 4: Create Reader Implementation
+
+**Create:** `src/SharpCompress/Readers/NewFormat/NewFormatReader.cs`
+
+```csharp
+public class NewFormatReader : AbstractReader
+{
+    private NewFormatHeader _header;
+    private BinaryReader _reader;
+    
+    public NewFormatReader(Stream stream)
+    {
+        _reader = new BinaryReader(stream);
+        _header = NewFormatHeader.Read(_reader);
+    }
+    
+    public override bool MoveToNextEntry()
+    {
+        // Read next entry header
+        if (!_reader.BaseStream.CanRead) return false;
+        
+        var entryData = NewFormatEntry.Read(_reader);
+        // ... set this.Entry
+        return entryData != null;
+    }
+    
+    // ... other abstract method implementations
+}
+```
+
+### Step 5: Create Factory
+
+**Create:** `src/SharpCompress/Factories/NewFormatFactory.cs`
+
+```csharp
+public class NewFormatFactory : Factory, IArchiveFactory, IReaderFactory
+{
+    // Archive format magic bytes (signature)
+    private static readonly byte[] NewFormatSignature = new byte[] { 0x4E, 0x46 };  // "NF"
+    
+    public static NewFormatFactory Instance { get; } = new();
+    
+    public IArchive CreateArchive(Stream stream)
+        => NewFormatArchive.OpenArchive(stream);
+    
+    public IReader CreateReader(Stream stream, ReaderOptions options)
+        => new NewFormatReader(stream) { Options = options };
+    
+    public bool Matches(Stream stream, ReadOnlySpan<byte> signature) 
+        => signature.StartsWith(NewFormatSignature);
+}
+```
+
+### Step 6: Register Factory
+
+**Update:** `src/SharpCompress/Factories/ArchiveFactory.cs`
+
+```csharp
+private static readonly IFactory[] Factories = 
+{
+    ZipFactory.Instance,
+    TarFactory.Instance,
+    RarFactory.Instance,
+    SevenZipFactory.Instance,
+    GZipFactory.Instance,
+    NewFormatFactory.Instance,  // Add here
+    // ... other factories
+};
+```
+
+### Step 7: Add Tests
+
+**Create:** `tests/SharpCompress.Test/NewFormat/NewFormatTests.cs`
+
+```csharp
+public class NewFormatTests : TestBase
+{
+    [Fact]
+    public void NewFormat_Extracts_Successfully()
+    {
+        var archivePath = Path.Combine(TEST_ARCHIVES_PATH, "archive.newformat");
+        using (var archive = NewFormatArchive.OpenArchive(archivePath))
+        {
+            archive.WriteToDirectory(SCRATCH_FILES_PATH);
+            // Assert extraction
+        }
+    }
+    
+    [Fact]
+    public void NewFormat_Reader_Works()
+    {
+        var archivePath = Path.Combine(TEST_ARCHIVES_PATH, "archive.newformat");
+        using (var stream = File.OpenRead(archivePath))
+        using (var reader = new NewFormatReader(stream))
+        {
+            Assert.True(reader.MoveToNextEntry());
+            Assert.NotNull(reader.Entry);
+        }
+    }
+}
+```
+
+### Step 8: Add Test Archives
+
+Place test files in `tests/TestArchives/Archives/NewFormat/` directory.
+
+### Step 9: Document
+
+Update `docs/FORMATS.md` with format support information.
+
+---
+
+## Compression Algorithm Implementation
+
+### Creating a New Compression Stream
+
+**Example:** Creating `CustomStream` for a custom compression algorithm
+
+```csharp
+public class CustomStream : Stream
+{
+    private readonly Stream _baseStream;
+    private readonly bool _leaveOpen;
+    
+    public CustomStream(Stream baseStream, bool leaveOpen = false)
+    {
+        _baseStream = baseStream;
+        _leaveOpen = leaveOpen;
+    }
+    
+    public override int Read(byte[] buffer, int offset, int count)
+    {
+        // Decompress data from _baseStream into buffer
+        // Return number of decompressed bytes
+    }
+    
+    public override void Write(byte[] buffer, int offset, int count)
+    {
+        // Compress data from buffer into _baseStream
+    }
+    
+    protected override void Dispose(bool disposing)
+    {
+        if (disposing && !_leaveOpen)
+        {
+            _baseStream?.Dispose();
+        }
+        base.Dispose(disposing);
+    }
+}
+```
+
+---
+
+## Stream Handling Best Practices
+
+### Disposal Pattern
+
+```csharp
+// Correct: Nested using blocks
+using (var fileStream = File.OpenRead("archive.zip"))
+using (var archive = ZipArchive.OpenArchive(fileStream))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+// Both archive and fileStream properly disposed
+
+// Correct: Using with options
+var options = new ReaderOptions { LeaveStreamOpen = true };
+var stream = File.OpenRead("archive.zip");
+using (var archive = ZipArchive.OpenArchive(stream, options))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+stream.Dispose();  // Manually dispose if LeaveStreamOpen = true
+```
+
+### NonDisposingStream Wrapper
+
+```csharp
+// Prevent unwanted stream closure
+var baseStream = File.OpenRead("data.bin");
+var nonDisposing = new NonDisposingStream(baseStream);
+
+using (var compressor = new DeflateStream(nonDisposing))
+{
+    // Compressor won't close baseStream when disposed
+}
+
+// baseStream still usable
+baseStream.Position = 0;  // Works
+baseStream.Dispose();  // Manual disposal
+```
+
+---
+
+## Performance Considerations
+
+### Memory Efficiency
+
+1. **Avoid loading entire archive in memory** - Use Reader API for large files
+2. **Process entries sequentially** - Especially for solid archives
+3. **Use appropriate buffer sizes** - Larger buffers for network I/O
+4. **Dispose streams promptly** - Free resources when done
+
+### Algorithm Selection
+
+1. **Archive API** - Fast for small archives with random access
+2. **Reader API** - Efficient for large files or streaming
+3. **Solid archives** - Sequential extraction much faster
+4. **Compression levels** - Trade-off between speed and size
+
+---
+
+## Testing Guidelines
+
+### Test Coverage
+
+1. **Happy path** - Normal extraction works
+2. **Edge cases** - Empty archives, single file, many files
+3. **Corrupted data** - Handle gracefully
+4. **Error cases** - Missing passwords, unsupported compression
+5. **Async operations** - Both sync and async code paths
+
+### Test Archives
+
+- Use `tests/TestArchives/` for test data
+- Create format-specific subdirectories
+- Include encrypted, corrupted, and edge case archives
+- Don't recreate existing archives
+
+### Test Patterns
+
+```csharp
+[Fact]
+public void Archive_Extraction_Works()
+{
+    // Arrange
+    var testArchive = Path.Combine(TEST_ARCHIVES_PATH, "test.zip");
+    
+    // Act
+    using (var archive = ZipArchive.OpenArchive(testArchive))
+    {
+        archive.WriteToDirectory(SCRATCH_FILES_PATH);
+    }
+    
+    // Assert
+    Assert.True(File.Exists(Path.Combine(SCRATCH_FILES_PATH, "file.txt")));
+}
+```
+
+---
+
+## Related Documentation
+
+- [AGENTS.md](../AGENTS.md) - Development guidelines
+- [FORMATS.md](FORMATS.md) - Supported formats

docs/ENCODING.md

@@ -0,0 +1,610 @@
+# SharpCompress Character Encoding Guide
+
+This guide explains how SharpCompress handles character encoding for archive entries (filenames, comments, etc.).
+
+## Overview
+
+Most archive formats store filenames and metadata as bytes. SharpCompress must convert these bytes to strings using the appropriate character encoding.
+
+**Common Problem:** Archives created on systems with non-UTF8 encodings (especially Japanese, Chinese systems) appear with corrupted filenames when extracted on systems that assume UTF8.
+
+---
+
+## ArchiveEncoding Class
+
+### Basic Usage
+
+```csharp
+using SharpCompress.Common;
+using SharpCompress.Readers;
+
+// Configure encoding before opening archive
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding(932)  // cp932 for Japanese
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("japanese.zip", options))
+{
+    foreach (var entry in archive.Entries)
+    {
+        Console.WriteLine(entry.Key);  // Now shows correct characters
+    }
+}
+```
+
+### ArchiveEncoding Properties
+
+| Property | Purpose |
+|----------|---------|
+| `Default` | Default encoding for filenames (fallback) |
+| `CustomDecoder` | Custom decoding function for special cases |
+
+### Setting for Different APIs
+
+**Archive API:**
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding { Default = Encoding.GetEncoding(932) }
+};
+using (var archive = ZipArchive.OpenArchive("file.zip", options))
+{
+    // Use archive with correct encoding
+}
+```
+
+**Reader API:**
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding { Default = Encoding.GetEncoding(932) }
+};
+using (var stream = File.OpenRead("file.zip"))
+using (var reader = ReaderFactory.OpenReader(stream, options))
+{
+    while (reader.MoveToNextEntry())
+    {
+        // Filenames decoded correctly
+    }
+}
+```
+
+---
+
+## Common Encodings
+
+### Asian Encodings
+
+#### cp932 (Japanese)
+```csharp
+// Windows-31J, Shift-JIS variant used on Japanese Windows
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding(932)
+    }
+};
+using (var archive = ZipArchive.OpenArchive("japanese.zip", options))
+{
+    // Correctly decodes Japanese filenames
+}
+```
+
+**When to use:**
+- Archives from Japanese Windows systems
+- Files with Japanese characters in names
+
+#### gb2312 (Simplified Chinese)
+```csharp
+// Simplified Chinese
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("gb2312")
+    }
+};
+```
+
+#### gbk (Extended Simplified Chinese)
+```csharp
+// Extended Simplified Chinese (more characters than gb2312)
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("gbk")
+    }
+};
+```
+
+#### big5 (Traditional Chinese)
+```csharp
+// Traditional Chinese (Taiwan, Hong Kong)
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("big5")
+    }
+};
+```
+
+#### euc-jp (Japanese, Unix)
+```csharp
+// Extended Unix Code for Japanese
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("eucjp")
+    }
+};
+```
+
+#### euc-kr (Korean)
+```csharp
+// Extended Unix Code for Korean
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("euc-kr")
+    }
+};
+```
+
+### Western European Encodings
+
+#### iso-8859-1 (Latin-1)
+```csharp
+// Western European (includes accented characters)
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("iso-8859-1")
+    }
+};
+```
+
+**When to use:**
+- Archives from French, German, Spanish systems
+- Files with accented characters (é, ñ, ü, etc.)
+
+#### cp1252 (Windows-1252)
+```csharp
+// Windows Western European
+// Very similar to iso-8859-1 but with additional printable characters
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("cp1252")
+    }
+};
+```
+
+**When to use:**
+- Archives from older Western European Windows systems
+- Files with smart quotes and other Windows-specific characters
+
+#### iso-8859-15 (Latin-9)
+```csharp
+// Western European with Euro symbol support
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("iso-8859-15")
+    }
+};
+```
+
+### Cyrillic Encodings
+
+#### cp1251 (Windows Cyrillic)
+```csharp
+// Russian, Serbian, Bulgarian, etc.
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("cp1251")
+    }
+};
+```
+
+#### koi8-r (KOI8 Russian)
+```csharp
+// Russian (Unix standard)
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("koi8-r")
+    }
+};
+```
+
+### UTF Encodings (Modern)
+
+#### UTF-8 (Default)
+```csharp
+// Modern standard - usually correct for new archives
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.UTF8
+    }
+};
+```
+
+#### UTF-16
+```csharp
+// Unicode - rarely used in archives
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.Unicode
+    }
+};
+```
+
+---
+
+## Encoding Auto-Detection
+
+SharpCompress attempts to auto-detect encoding, but this isn't always reliable:
+
+```csharp
+// Auto-detection (default)
+using (var archive = ZipArchive.OpenArchive("file.zip"))  // Uses UTF8 by default
+{
+    // May show corrupted characters if archive uses different encoding
+}
+
+// Explicit encoding (more reliable)
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding { Default = Encoding.GetEncoding(932) }
+};
+using (var archive = ZipArchive.OpenArchive("file.zip", options))
+{
+    // Correct characters displayed
+}
+```
+
+### When Manual Override is Needed
+
+| Situation | Solution |
+|-----------|----------|
+| Archive shows corrupted characters | Specify the encoding explicitly |
+| Archives from specific region | Use that region's encoding |
+| Mixed encodings in archive | Use CustomDecoder |
+| Testing with international files | Try different encodings |
+
+---
+
+## Custom Decoder
+
+For complex scenarios where a single encoding isn't sufficient:
+
+### Basic Custom Decoder
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding
+    {
+        CustomDecoder = (data, offset, length) =>
+        {
+            // Custom decoding logic
+            var bytes = new byte[length];
+            Array.Copy(data, offset, bytes, 0, length);
+            
+            // Try UTF8 first
+            try
+            {
+                return Encoding.UTF8.GetString(bytes);
+            }
+            catch
+            {
+                // Fallback to cp932 if UTF8 fails
+                return Encoding.GetEncoding(932).GetString(bytes);
+            }
+        }
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("mixed.zip", options))
+{
+    foreach (var entry in archive.Entries)
+    {
+        Console.WriteLine(entry.Key);  // Uses custom decoder
+    }
+}
+```
+
+### Advanced: Detect Encoding by Content
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding
+    {
+        CustomDecoder = DetectAndDecode
+    }
+};
+
+private static string DetectAndDecode(byte[] data, int offset, int length)
+{
+    var bytes = new byte[length];
+    Array.Copy(data, offset, bytes, 0, length);
+    
+    // Try UTF8 (most modern archives)
+    try
+    {
+        var str = Encoding.UTF8.GetString(bytes);
+        // Verify it decoded correctly (no replacement characters)
+        if (!str.Contains('\uFFFD'))
+            return str;
+    }
+    catch { }
+    
+    // Try cp932 (Japanese)
+    try
+    {
+        var str = Encoding.GetEncoding(932).GetString(bytes);
+        if (!str.Contains('\uFFFD'))
+            return str;
+    }
+    catch { }
+    
+    // Fallback to iso-8859-1 (always succeeds)
+    return Encoding.GetEncoding("iso-8859-1").GetString(bytes);
+}
+```
+
+---
+
+## Code Examples
+
+### Extract Archive with Japanese Filenames
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding(932)  // cp932
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("japanese_files.zip", options))
+{
+    archive.WriteToDirectory(@"C:\output", new ExtractionOptions
+    {
+        ExtractFullPath = true,
+        Overwrite = true
+    });
+}
+// Files extracted with correct Japanese names
+```
+
+### Extract Archive with Western European Filenames
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("iso-8859-1")
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("french_files.zip", options))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+// Accented characters (é, è, ê, etc.) display correctly
+```
+
+### Extract Archive with Chinese Filenames
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("gbk")  // Simplified Chinese
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("chinese_files.zip", options))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+```
+
+### Extract Archive with Russian Filenames
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("cp1251")  // Windows Cyrillic
+    }
+};
+
+using (var archive = ZipArchive.OpenArchive("russian_files.zip", options))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+```
+
+### Reader API with Encoding
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding(932)
+    }
+};
+
+using (var stream = File.OpenRead("japanese.zip"))
+using (var reader = ReaderFactory.OpenReader(stream, options))
+{
+    while (reader.MoveToNextEntry())
+    {
+        if (!reader.Entry.IsDirectory)
+        {
+            Console.WriteLine(reader.Entry.Key);  // Correct characters
+            reader.WriteEntryToDirectory(@"C:\output");
+        }
+    }
+}
+```
+
+---
+
+## Creating Archives with Correct Encoding
+
+When creating archives, SharpCompress uses UTF8 by default (recommended):
+
+```csharp
+// Create with UTF8 (default, recommended)
+using (var archive = ZipArchive.CreateArchive())
+{
+    archive.AddAllFromDirectory(@"D:\my_files");
+    archive.SaveTo("output.zip", CompressionType.Deflate);
+    // Archives created with UTF8 encoding
+}
+```
+
+If you need to create archives for systems that expect specific encodings:
+
+```csharp
+// Note: SharpCompress Writer API uses UTF8 for encoding
+// To create archives with other encodings, consider:
+// 1. Let users on those systems create archives
+// 2. Use system tools (7-Zip, WinRAR) with desired encoding
+// 3. Post-process archives if absolutely necessary
+
+// For now, recommend modern UTF8-based archives
+```
+
+---
+
+## Troubleshooting Encoding Issues
+
+### Filenames Show Question Marks (?)
+
+```
+✗ Wrong encoding detected
+test文件.txt → test???.txt
+```
+
+**Solution:** Specify correct encoding explicitly
+
+```csharp
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding 
+    { 
+        Default = Encoding.GetEncoding("gbk")  // Try different encodings
+    }
+};
+```
+
+### Filenames Show Replacement Character (￿)
+
+```
+✗ Invalid bytes for selected encoding
+café.txt → caf￿.txt
+```
+
+**Solution:**
+1. Try a different encoding (see Common Encodings table)
+2. Use CustomDecoder with fallback encoding
+3. Archive might be corrupted
+
+### Mixed Encodings in Single Archive
+
+```csharp
+// Use CustomDecoder to handle mixed encodings
+var options = new ReaderOptions
+{
+    ArchiveEncoding = new ArchiveEncoding
+    {
+        CustomDecoder = (data, offset, length) =>
+        {
+            // Try multiple encodings in priority order
+            var bytes = new byte[length];
+            Array.Copy(data, offset, bytes, 0, length);
+            
+            foreach (var encoding in new[] 
+            {
+                Encoding.UTF8,
+                Encoding.GetEncoding(932),
+                Encoding.GetEncoding("iso-8859-1")
+            })
+            {
+                try
+                {
+                    var str = encoding.GetString(bytes);
+                    if (!str.Contains('\uFFFD'))
+                        return str;
+                }
+                catch { }
+            }
+            
+            // Final fallback
+            return Encoding.GetEncoding("iso-8859-1").GetString(bytes);
+        }
+    }
+};
+```
+
+---
+
+## Encoding Reference Table
+
+| Encoding | Code | Use Case |
+|----------|------|----------|
+| UTF-8 | (default) | Modern archives, recommended |
+| cp932 | 932 | Japanese Windows |
+| gb2312 | "gb2312" | Simplified Chinese |
+| gbk | "gbk" | Extended Simplified Chinese |
+| big5 | "big5" | Traditional Chinese |
+| iso-8859-1 | "iso-8859-1" | Western European |
+| cp1252 | "cp1252" | Windows Western European |
+| cp1251 | "cp1251" | Russian/Cyrillic |
+| euc-jp | "euc-jp" | Japanese Unix |
+| euc-kr | "euc-kr" | Korean |
+
+---
+
+## Best Practices
+
+1. **Use UTF-8 for new archives** - Most modern systems support it
+2. **Ask the archive creator** - When receiving archives with corrupted names
+3. **Provide encoding options** - If your app handles user archives
+4. **Document your assumption** - Tell users what encoding you're using
+5. **Test with international files** - Before releasing production code
+
+---
+
+## Related Documentation
+
+- [USAGE.md](USAGE.md#extract-zip-which-has-non-utf8-encoded-filenamycp932) - Usage examples

docs/PERFORMANCE.md

@@ -0,0 +1,474 @@
+# SharpCompress Performance Guide
+
+This guide helps you optimize SharpCompress for performance in various scenarios.
+
+## API Selection Guide
+
+### Archive API vs Reader API
+
+Choose the right API based on your use case:
+
+| Aspect | Archive API | Reader API |
+|--------|------------|-----------|
+| **Stream Type** | Seekable only | Non-seekable OK |
+| **Memory Usage** | All entries in memory | One entry at a time |
+| **Random Access** | ✓ Yes | ✗ No |
+| **Best For** | Small-to-medium archives | Large or streaming data |
+| **Performance** | Fast for random access | Better for large files |
+
+### Archive API (Fast for Random Access)
+
+```csharp
+// Use when:
+// - Archive fits in memory
+// - You need random access to entries
+// - Stream is seekable (file, MemoryStream)
+
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    // Random access - all entries available
+    var specific = archive.Entries.FirstOrDefault(e => e.Key == "file.txt");
+    if (specific != null)
+    {
+        specific.WriteToFile(@"C:\output\file.txt");
+    }
+}
+```
+
+**Performance Characteristics:**
+- ✓ Instant entry lookup
+- ✓ Parallel extraction possible
+- ✗ Entire archive in memory
+- ✗ Can't process while downloading
+
+### Reader API (Best for Large Files)
+
+```csharp
+// Use when:
+// - Processing large archives (>100 MB)
+// - Streaming from network/pipe
+// - Memory is constrained
+// - Forward-only processing is acceptable
+
+using (var stream = File.OpenRead("large.zip"))
+using (var reader = ReaderFactory.OpenReader(stream))
+{
+    while (reader.MoveToNextEntry())
+    {
+        // Process one entry at a time
+        reader.WriteEntryToDirectory(@"C:\output");
+    }
+}
+```
+
+**Performance Characteristics:**
+- ✓ Minimal memory footprint
+- ✓ Works with non-seekable streams
+- ✓ Can process while downloading
+- ✗ Forward-only (no random access)
+- ✗ Entry lookup requires iteration
+
+---
+
+## Buffer Sizing
+
+### Understanding Buffers
+
+SharpCompress uses internal buffers for reading compressed data. Buffer size affects:
+- **Speed:** Larger buffers = fewer I/O operations = faster
+- **Memory:** Larger buffers = higher memory usage
+
+### Recommended Buffer Sizes
+
+| Scenario | Size | Notes |
+|----------|------|-------|
+| Embedded/IoT devices | 4-8 KB | Minimal memory usage |
+| Memory-constrained | 16-32 KB | Conservative default |
+| Standard use (default) | 64 KB | Recommended default |
+| Large file streaming | 256 KB | Better throughput |
+| High-speed SSD | 512 KB - 1 MB | Maximum throughput |
+
+### How Buffer Size Affects Performance
+
+```csharp
+// SharpCompress manages buffers internally
+// You can't directly set buffer size, but you can:
+
+// 1. Use Stream.CopyTo with explicit buffer size
+using (var entryStream = reader.OpenEntryStream())
+using (var fileStream = File.Create(@"C:\output\file.txt"))
+{
+    // 64 KB buffer (default)
+    entryStream.CopyTo(fileStream);
+    
+    // Or specify larger buffer for faster copy
+    entryStream.CopyTo(fileStream, bufferSize: 262144);  // 256 KB
+}
+
+// 2. Use custom buffer for writing
+using (var entryStream = reader.OpenEntryStream())
+using (var fileStream = File.Create(@"C:\output\file.txt"))
+{
+    byte[] buffer = new byte[262144];  // 256 KB
+    int bytesRead;
+    while ((bytesRead = entryStream.Read(buffer, 0, buffer.Length)) > 0)
+    {
+        fileStream.Write(buffer, 0, bytesRead);
+    }
+}
+```
+
+---
+
+## Streaming Large Files
+
+### Non-Seekable Stream Patterns
+
+For processing archives from downloads or pipes:
+
+```csharp
+// Download stream (non-seekable)
+using (var httpStream = await httpClient.GetStreamAsync(url))
+using (var reader = ReaderFactory.OpenReader(httpStream))
+{
+    // Process entries as they arrive
+    while (reader.MoveToNextEntry())
+    {
+        if (!reader.Entry.IsDirectory)
+        {
+            reader.WriteEntryToDirectory(@"C:\output");
+        }
+    }
+}
+```
+
+**Performance Tips:**
+- Don't try to buffer the entire stream
+- Process entries immediately
+- Use async APIs for better responsiveness
+
+### Download-Then-Extract vs Streaming
+
+Choose based on your constraints:
+
+| Approach | When to Use |
+|----------|------------|
+| **Download then extract** | Moderate size, need random access |
+| **Stream during download** | Large files, bandwidth limited, memory constrained |
+
+```csharp
+// Download then extract (requires disk space)
+var archivePath = await DownloadFile(url, @"C:\temp\archive.zip");
+using (var archive = ZipArchive.OpenArchive(archivePath))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+
+// Stream during download (on-the-fly extraction)
+using (var httpStream = await httpClient.GetStreamAsync(url))
+using (var reader = ReaderFactory.OpenReader(httpStream))
+{
+    while (reader.MoveToNextEntry())
+    {
+        reader.WriteEntryToDirectory(@"C:\output");
+    }
+}
+```
+
+---
+
+## Solid Archive Optimization
+
+### Why Solid Archives Are Slow
+
+Solid archives (Rar, 7Zip) group files together in a single compressed stream:
+
+```
+Solid Archive Layout:
+[Header] [Compressed Stream] [Footer]
+         ├─ File1 compressed data
+         ├─ File2 compressed data
+         ├─ File3 compressed data
+         └─ File4 compressed data
+```
+
+Extracting File3 requires decompressing File1 and File2 first.
+
+### Sequential vs Random Extraction
+
+**Random Extraction (Slow):**
+```csharp
+using (var archive = RarArchive.OpenArchive("solid.rar"))
+{
+    foreach (var entry in archive.Entries)
+    {
+        entry.WriteToFile(@"C:\output\" + entry.Key);  // ✗ Slow!
+        // Each entry triggers full decompression from start
+    }
+}
+```
+
+**Sequential Extraction (Fast):**
+```csharp
+using (var archive = RarArchive.OpenArchive("solid.rar"))
+{
+    // Method 1: Use WriteToDirectory (recommended)
+    archive.WriteToDirectory(@"C:\output", new ExtractionOptions
+    {
+        ExtractFullPath = true,
+        Overwrite = true
+    });
+    
+    // Method 2: Use ExtractAllEntries
+    archive.ExtractAllEntries();
+    
+    // Method 3: Use Reader API (also sequential)
+    using (var reader = RarReader.Open(File.OpenRead("solid.rar")))
+    {
+        while (reader.MoveToNextEntry())
+        {
+            reader.WriteEntryToDirectory(@"C:\output");
+        }
+    }
+}
+```
+
+**Performance Impact:**
+- Random extraction: O(n²) - very slow for many files
+- Sequential extraction: O(n) - 10-100x faster
+
+### Best Practices for Solid Archives
+
+1. **Always extract sequentially** when possible
+2. **Use Reader API** for large solid archives
+3. **Process entries in order** from the archive
+4. **Consider using 7Zip command-line** for scripted extractions
+
+---
+
+## Compression Level Trade-offs
+
+### Deflate/GZip Levels
+
+```csharp
+// Level 1 = Fastest, largest size
+// Level 6 = Default (balanced)
+// Level 9 = Slowest, best compression
+
+// Write with different compression levels
+using (var archive = ZipArchive.CreateArchive())
+{
+    archive.AddAllFromDirectory(@"D:\data");
+    
+    // Fast compression (level 1)
+    archive.SaveTo("fast.zip", new WriterOptions(CompressionType.Deflate)
+    {
+        CompressionLevel = 1
+    });
+    
+    // Default compression (level 6)
+    archive.SaveTo("default.zip", CompressionType.Deflate);
+    
+    // Best compression (level 9)
+    archive.SaveTo("best.zip", new WriterOptions(CompressionType.Deflate)
+    {
+        CompressionLevel = 9
+    });
+}
+```
+
+**Speed vs Size:**
+| Level | Speed | Size | Use Case |
+|-------|-------|------|----------|
+| 1 | 10x | 90% | Network, streaming |
+| 6 | 1x | 75% | Default (good balance) |
+| 9 | 0.1x | 65% | Archival, static storage |
+
+### BZip2 Block Size
+
+```csharp
+// BZip2 block size affects memory and compression
+// 100K to 900K (default 900K)
+
+// Smaller block size = lower memory, faster
+// Larger block size = better compression, slower
+
+using (var archive = TarArchive.CreateArchive())
+{
+    archive.AddAllFromDirectory(@"D:\data");
+    
+    // These are preset in WriterOptions via CompressionLevel
+    archive.SaveTo("archive.tar.bz2", CompressionType.BZip2);
+}
+```
+
+### LZMA Settings
+
+LZMA compression is very powerful but memory-intensive:
+
+```csharp
+// LZMA (7Zip, .tar.lzma):
+// - Dictionary size: 16 KB to 1 GB (default 32 MB)
+// - Faster preset: smaller dictionary
+// - Better compression: larger dictionary
+
+// Preset via CompressionType
+using (var archive = TarArchive.CreateArchive())
+{
+    archive.AddAllFromDirectory(@"D:\data");
+    archive.SaveTo("archive.tar.xz", CompressionType.LZMA);  // Default settings
+}
+```
+
+---
+
+## Async Performance
+
+### When Async Helps
+
+Async is beneficial when:
+- **Long I/O operations** (network, slow disks)
+- **UI responsiveness** needed (Windows Forms, WPF, Blazor)
+- **Server applications** (ASP.NET, multiple concurrent operations)
+
+```csharp
+// Async extraction (non-blocking)
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    await archive.WriteToDirectoryAsync(
+        @"C:\output",
+        new ExtractionOptions { ExtractFullPath = true, Overwrite = true },
+        cancellationToken
+    );
+}
+// Thread can handle other work while I/O happens
+```
+
+### When Async Doesn't Help
+
+Async doesn't improve performance for:
+- **CPU-bound operations** (already fast)
+- **Local SSD I/O** (I/O is fast enough)
+- **Single-threaded scenarios** (no parallelism benefit)
+
+```csharp
+// Sync extraction (simpler, same performance on fast I/O)
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    archive.WriteToDirectory(
+        @"C:\output",
+        new ExtractionOptions { ExtractFullPath = true, Overwrite = true }
+    );
+}
+// Simple and fast - no async needed
+```
+
+### Cancellation Pattern
+
+```csharp
+var cts = new CancellationTokenSource();
+
+// Cancel after 5 minutes
+cts.CancelAfter(TimeSpan.FromMinutes(5));
+
+try
+{
+    using (var archive = ZipArchive.OpenArchive("archive.zip"))
+    {
+        await archive.WriteToDirectoryAsync(
+            @"C:\output",
+            new ExtractionOptions { ExtractFullPath = true, Overwrite = true },
+            cts.Token
+        );
+    }
+}
+catch (OperationCanceledException)
+{
+    Console.WriteLine("Extraction cancelled");
+    // Clean up partial extraction if needed
+}
+```
+
+---
+
+## Practical Performance Tips
+
+### 1. Choose the Right API
+
+| Scenario | API | Why |
+|----------|-----|-----|
+| Small archives | Archive | Faster random access |
+| Large archives | Reader | Lower memory |
+| Streaming | Reader | Works on non-seekable streams |
+| Download streams | Reader | Async extraction while downloading |
+
+### 2. Batch Operations
+
+```csharp
+// ✗ Slow - opens each archive separately
+foreach (var file in files)
+{
+    using (var archive = ZipArchive.OpenArchive("archive.zip"))
+    {
+        archive.WriteToDirectory(@"C:\output");
+    }
+}
+
+// ✓ Better - process multiple entries at once
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+```
+
+### 3. Profile Your Code
+
+```csharp
+var sw = Stopwatch.StartNew();
+using (var archive = ZipArchive.OpenArchive("large.zip"))
+{
+    archive.WriteToDirectory(@"C:\output");
+}
+sw.Stop();
+
+Console.WriteLine($"Extraction took {sw.ElapsedMilliseconds}ms");
+
+// Measure memory before/after
+var beforeMem = GC.GetTotalMemory(true);
+// ... do work ...
+var afterMem = GC.GetTotalMemory(true);
+Console.WriteLine($"Memory used: {(afterMem - beforeMem) / 1024 / 1024}MB");
+```
+
+---
+
+## Troubleshooting Performance
+
+### Extraction is Slow
+
+1. **Check if solid archive** → Use sequential extraction
+2. **Check API** → Reader API might be faster for large files
+3. **Check compression level** → Higher levels are slower to decompress
+4. **Check I/O** → Network drives are much slower than SSD
+5. **Check buffer size** → May need larger buffers for network
+
+### High Memory Usage
+
+1. **Use Reader API** instead of Archive API
+2. **Process entries immediately** rather than buffering
+3. **Reduce compression level** if writing
+4. **Check for memory leaks** in your code
+
+### CPU Usage at 100%
+
+1. **Normal for compression** - especially with high compression levels
+2. **Consider lower level** for faster processing
+3. **Reduce parallelism** if processing multiple archives
+4. **Check if awaiting properly** in async code
+
+---
+
+## Related Documentation
+
+- [PERFORMANCE.md](USAGE.md) - Usage examples with performance considerations
+- [FORMATS.md](FORMATS.md) - Format-specific performance notes

docs/USAGE.md

@@ -1,6 +1,6 @@
 # SharpCompress Usage
 
-## Async/Await Support
+## Async/Await Support (Beta)
 
 SharpCompress now provides full async/await support for all I/O operations. All `Read`, `Write`, and extraction operations have async equivalents ending in `Async` that accept an optional `CancellationToken`. This enables better performance and scalability for I/O-bound operations.
 
@@ -13,7 +13,7 @@ SharpCompress now provides full async/await support for all I/O operations. All
 
 See [Async Examples](#async-examples) section below for usage patterns.
 
-## Stream Rules (changed with 0.21)
+## Stream Rules
 
 When dealing with Streams, the rule should be that you don't close a stream you didn't create. This, in effect, should mean you should always put a Stream in a using block to dispose it. 
 
@@ -48,7 +48,7 @@ Also, look over the tests for more thorough [examples](https://github.com/adamha
 
 ### Create Zip Archive from multiple files
 ```C#
-using(var archive = ZipArchive.Create())
+using(var archive = ZipArchive.CreateArchive())
 {
     archive.AddEntry("file01.txt", "C:\\file01.txt");
     archive.AddEntry("file02.txt", "C:\\file02.txt");
@@ -61,7 +61,7 @@ using(var archive = ZipArchive.Create())
 ### Create Zip Archive from all files in a directory to a file
 
 ```C#
-using (var archive = ZipArchive.Create())
+using (var archive = ZipArchive.CreateArchive())
 {
     archive.AddAllFromDirectory("D:\\temp");
     archive.SaveTo("C:\\temp.zip", CompressionType.Deflate);
@@ -72,7 +72,7 @@ using (var archive = ZipArchive.Create())
 
 ```C#
 var memoryStream = new MemoryStream();
-using (var archive = ZipArchive.Create())
+using (var archive = ZipArchive.CreateArchive())
 {
     archive.AddAllFromDirectory("D:\\temp");
     archive.SaveTo(memoryStream, new WriterOptions(CompressionType.Deflate)
@@ -90,7 +90,7 @@ Note: Extracting a solid rar or 7z file needs to be done in sequential order to
 `ExtractAllEntries` is primarily intended for solid archives (like solid Rar) or 7Zip archives, where sequential extraction provides the best performance. For general/simple extraction with any supported archive type, use `archive.WriteToDirectory()` instead.
 
 ```C#
-using (var archive = RarArchive.Open("Test.rar"))
+using (var archive = RarArchive.OpenArchive("Test.rar"))
 {
     // Simple extraction with RarArchive; this WriteToDirectory pattern works for all archive types
     archive.WriteToDirectory(@"D:\temp", new ExtractionOptions()
@@ -104,7 +104,7 @@ using (var archive = RarArchive.Open("Test.rar"))
 ### Iterate over all files from a Rar file using RarArchive
 
 ```C#
-using (var archive = RarArchive.Open("Test.rar"))
+using (var archive = RarArchive.OpenArchive("Test.rar"))
 {
     foreach (var entry in archive.Entries.Where(entry => !entry.IsDirectory))
     {
@@ -126,7 +126,7 @@ var progress = new Progress<ProgressReport>(report =>
     Console.WriteLine($"Extracting {report.EntryPath}: {report.PercentComplete}%");
 });
 
-using (var archive = RarArchive.Open("archive.rar", new ReaderOptions { Progress = progress })) // Must be solid Rar or 7Zip
+using (var archive = RarArchive.OpenArchive("archive.rar", new ReaderOptions { Progress = progress })) // Must be solid Rar or 7Zip
 {
     archive.WriteToDirectory(@"D:\output", new ExtractionOptions()
     {
@@ -140,7 +140,7 @@ using (var archive = RarArchive.Open("archive.rar", new ReaderOptions { Progress
 
 ```C#
 using (Stream stream = File.OpenRead("Tar.tar.bz2"))
-using (var reader = ReaderFactory.Open(stream))
+using (var reader = ReaderFactory.OpenReader(stream))
 {
     while (reader.MoveToNextEntry())
     {
@@ -161,7 +161,7 @@ using (var reader = ReaderFactory.Open(stream))
 
 ```C#
 using (Stream stream = File.OpenRead("Tar.tar.bz2"))
-using (var reader = ReaderFactory.Open(stream))
+using (var reader = ReaderFactory.OpenReader(stream))
 {
     while (reader.MoveToNextEntry())
     {
@@ -180,7 +180,7 @@ using (var reader = ReaderFactory.Open(stream))
 
 ```C#
 using (Stream stream = File.OpenWrite("C:\\temp.tgz"))
-using (var writer = WriterFactory.Open(stream, ArchiveType.Tar, new WriterOptions(CompressionType.GZip)
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Tar, new WriterOptions(CompressionType.GZip)
                                                 {
                                                     LeaveOpenStream = true
                                                 }))
@@ -199,7 +199,7 @@ opts.ArchiveEncoding.CustomDecoder = (data, x, y) =>
 {
     return encoding.GetString(data);
 };
-var tr = SharpCompress.Archives.Zip.ZipArchive.Open("test.zip", opts);
+var tr = SharpCompress.Archives.Zip.ZipArchive.OpenArchive("test.zip", opts);
 foreach(var entry in tr.Entries)
 {
     Console.WriteLine($"{entry.Key}");
@@ -213,7 +213,7 @@ foreach(var entry in tr.Entries)
 **Extract single entry asynchronously:**
 ```C#
 using (Stream stream = File.OpenRead("archive.zip"))
-using (var reader = ReaderFactory.Open(stream))
+using (var reader = ReaderFactory.OpenReader(stream))
 {
     while (reader.MoveToNextEntry())
     {
@@ -234,7 +234,7 @@ using (var reader = ReaderFactory.Open(stream))
 **Extract all entries asynchronously:**
 ```C#
 using (Stream stream = File.OpenRead("archive.tar.gz"))
-using (var reader = ReaderFactory.Open(stream))
+using (var reader = ReaderFactory.OpenReader(stream))
 {
     await reader.WriteAllToDirectoryAsync(
         @"D:\temp",
@@ -250,7 +250,7 @@ using (var reader = ReaderFactory.Open(stream))
 
 **Open and process entry stream asynchronously:**
 ```C#
-using (var archive = ZipArchive.Open("archive.zip"))
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
 {
     foreach (var entry in archive.Entries.Where(e => !e.IsDirectory))
     {
@@ -268,7 +268,7 @@ using (var archive = ZipArchive.Open("archive.zip"))
 **Write single file asynchronously:**
 ```C#
 using (Stream archiveStream = File.OpenWrite("output.zip"))
-using (var writer = WriterFactory.Open(archiveStream, ArchiveType.Zip, CompressionType.Deflate))
+using (var writer = WriterFactory.OpenWriter(archiveStream, ArchiveType.Zip, CompressionType.Deflate))
 {
     using (Stream fileStream = File.OpenRead("input.txt"))
     {
@@ -280,7 +280,7 @@ using (var writer = WriterFactory.Open(archiveStream, ArchiveType.Zip, Compressi
 **Write entire directory asynchronously:**
 ```C#
 using (Stream stream = File.OpenWrite("backup.tar.gz"))
-using (var writer = WriterFactory.Open(stream, ArchiveType.Tar, new WriterOptions(CompressionType.GZip)))
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Tar, new WriterOptions(CompressionType.GZip)))
 {
     await writer.WriteAllAsync(
         @"D:\files",
@@ -299,7 +299,7 @@ var cts = new CancellationTokenSource();
 cts.CancelAfter(TimeSpan.FromMinutes(5));
 
 using (Stream stream = File.OpenWrite("archive.zip"))
-using (var writer = WriterFactory.Open(stream, ArchiveType.Zip, CompressionType.Deflate))
+using (var writer = WriterFactory.OpenWriter(stream, ArchiveType.Zip, CompressionType.Deflate))
 {
     try
     {
@@ -316,7 +316,7 @@ using (var writer = WriterFactory.Open(stream, ArchiveType.Zip, CompressionType.
 
 **Extract from archive asynchronously:**
 ```C#
-using (var archive = ZipArchive.Open("archive.zip"))
+using (var archive = ZipArchive.OpenArchive("archive.zip"))
 {
     // Simple async extraction - works for all archive types
     await archive.WriteToDirectoryAsync(

src/SharpCompress/Algorithms/Adler32.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
-#if !NETSTANDARD2_0 && !NETSTANDARD2_1 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
 #define SUPPORTS_RUNTIME_INTRINSICS
 #define SUPPORTS_HOTPATH
 #endif

src/SharpCompress/Archives/AbstractArchive.cs

@@ -68,7 +68,7 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IAsyncArchive
     /// <summary>
     /// The total size of the files as uncompressed in the archive.
     /// </summary>
-    public virtual long TotalUncompressSize =>
+    public virtual long TotalUncompressedSize =>
         Entries.Aggregate(0L, (total, cf) => total + cf.Size);
 
     protected abstract IEnumerable<TVolume> LoadVolumes(SourceStream sourceStream);
@@ -145,6 +145,19 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IAsyncArchive
     /// </summary>
     public virtual bool IsEncrypted => false;
 
+    /// <summary>
+    /// Returns whether multi-threaded extraction is supported for this archive.
+    /// Multi-threading is supported when:
+    /// 1. The archive is opened from a FileInfo or file path (not a stream)
+    /// 2. Multi-threading is explicitly enabled in ReaderOptions
+    /// 3. The archive is not SOLID (SOLID archives should use sequential extraction)
+    /// </summary>
+    public virtual bool SupportsMultiThreadedExtraction =>
+        _sourceStream is not null
+        && _sourceStream.IsFileMode
+        && ReaderOptions.EnableMultiThreadedExtraction
+        && !IsSolid;
+
     /// <summary>
     /// The archive can find all the parts of the archive needed to fully extract the archive.  This forces the parsing of the entire archive.
     /// </summary>
@@ -187,10 +200,26 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IAsyncArchive
     }
 
     public virtual IAsyncEnumerable<TEntry> EntriesAsync => _lazyEntriesAsync;
-    IAsyncEnumerable<IArchiveEntry> IAsyncArchive.EntriesAsync =>
-        EntriesAsync.Cast<TEntry, IArchiveEntry>();
 
-    public IAsyncEnumerable<IVolume> VolumesAsync => _lazyVolumesAsync.Cast<TVolume, IVolume>();
+    private async IAsyncEnumerable<IArchiveEntry> EntriesAsyncCast()
+    {
+        await foreach (var entry in EntriesAsync)
+        {
+            yield return entry;
+        }
+    }
+
+    IAsyncEnumerable<IArchiveEntry> IAsyncArchive.EntriesAsync => EntriesAsyncCast();
+
+    private async IAsyncEnumerable<IVolume> VolumesAsyncCast()
+    {
+        await foreach (var volume in VolumesAsync)
+        {
+            yield return volume;
+        }
+    }
+
+    public IAsyncEnumerable<IVolume> VolumesAsync => VolumesAsyncCast();
 
     public async ValueTask<IAsyncReader> ExtractAllEntriesAsync()
     {
@@ -209,14 +238,16 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IAsyncArchive
     public async ValueTask<bool> IsCompleteAsync()
     {
         await EnsureEntriesLoadedAsync();
-        return await EntriesAsync.All(x => x.IsComplete);
+        return await EntriesAsync.AllAsync(x => x.IsComplete);
     }
 
     public async ValueTask<long> TotalSizeAsync() =>
-        await EntriesAsync.Aggregate(0L, (total, cf) => total + cf.CompressedSize);
+        await EntriesAsync.AggregateAsync(0L, (total, cf) => total + cf.CompressedSize);
 
-    public async ValueTask<long> TotalUncompressSizeAsync() =>
-        await EntriesAsync.Aggregate(0L, (total, cf) => total + cf.Size);
+    public async ValueTask<long> TotalUncompressedSizeAsync() =>
+        await EntriesAsync.AggregateAsync(0L, (total, cf) => total + cf.Size);
+
+    public ValueTask<bool> IsEncryptedAsync() => new(IsEncrypted);
 
     #endregion
 }

src/SharpCompress/Archives/AbstractWritableArchive.cs

@@ -12,7 +12,8 @@ namespace SharpCompress.Archives;
 
 public abstract class AbstractWritableArchive<TEntry, TVolume>
     : AbstractArchive<TEntry, TVolume>,
-        IWritableArchive
+        IWritableArchive,
+        IWritableAsyncArchive
     where TEntry : IArchiveEntry
     where TVolume : IVolume
 {
@@ -83,12 +84,12 @@ public abstract class AbstractWritableArchive<TEntry, TVolume>
         }
     }
 
-    void IWritableArchive.RemoveEntry(IArchiveEntry entry) => RemoveEntry((TEntry)entry);
+    void IWritableArchiveCommon.RemoveEntry(IArchiveEntry entry) => RemoveEntry((TEntry)entry);
 
     public TEntry AddEntry(string key, Stream source, long size = 0, DateTime? modified = null) =>
         AddEntry(key, source, false, size, modified);
 
-    IArchiveEntry IWritableArchive.AddEntry(
+    IArchiveEntry IWritableArchiveCommon.AddEntry(
         string key,
         Stream source,
         bool closeStream,
@@ -96,7 +97,7 @@ public abstract class AbstractWritableArchive<TEntry, TVolume>
         DateTime? modified
     ) => AddEntry(key, source, closeStream, size, modified);
 
-    IArchiveEntry IWritableArchive.AddDirectoryEntry(string key, DateTime? modified) =>
+    IArchiveEntry IWritableArchiveCommon.AddDirectoryEntry(string key, DateTime? modified) =>
         AddDirectoryEntry(key, modified);
 
     public TEntry AddEntry(

src/SharpCompress/Archives/ArchiveFactory.cs

@@ -13,27 +13,14 @@ namespace SharpCompress.Archives;
 
 public static class ArchiveFactory
 {
-    /// <summary>
-    /// Opens an Archive for random access
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <returns></returns>
-    public static IArchive Open(Stream stream, ReaderOptions? readerOptions = null)
+    public static IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null)
     {
         readerOptions ??= new ReaderOptions();
         stream = SharpCompressStream.Create(stream, bufferSize: readerOptions.BufferSize);
-        return FindFactory<IArchiveFactory>(stream).Open(stream, readerOptions);
+        return FindFactory<IArchiveFactory>(stream).OpenArchive(stream, readerOptions);
     }
 
-    /// <summary>
-    /// Opens an Archive for random access asynchronously
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    /// <returns></returns>
-    public static async ValueTask<IAsyncArchive> OpenAsync(
+    public static async ValueTask<IAsyncArchive> OpenAsyncArchive(
         Stream stream,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
@@ -41,14 +28,11 @@ public static class ArchiveFactory
     {
         readerOptions ??= new ReaderOptions();
         stream = SharpCompressStream.Create(stream, bufferSize: readerOptions.BufferSize);
-        var factory = await FindFactoryAsync<IArchiveFactory>(stream, cancellationToken)
-            .ConfigureAwait(false);
-        return await factory
-            .OpenAsync(stream, readerOptions, cancellationToken)
-            .ConfigureAwait(false);
+        var factory = await FindFactoryAsync<IArchiveFactory>(stream, cancellationToken);
+        return factory.OpenAsyncArchive(stream, readerOptions);
     }
 
-    public static IWritableArchive Create(ArchiveType type)
+    public static IWritableArchive CreateArchive(ArchiveType type)
     {
         var factory = Factory
             .Factories.OfType<IWriteableArchiveFactory>()
@@ -56,58 +40,36 @@ public static class ArchiveFactory
 
         if (factory != null)
         {
-            return factory.CreateWriteableArchive();
+            return factory.CreateArchive();
         }
 
         throw new NotSupportedException("Cannot create Archives of type: " + type);
     }
 
-    /// <summary>
-    /// Constructor expects a filepath to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="options"></param>
-    public static IArchive Open(string filePath, ReaderOptions? options = null)
+    public static IArchive OpenArchive(string filePath, ReaderOptions? options = null)
     {
         filePath.NotNullOrEmpty(nameof(filePath));
-        return Open(new FileInfo(filePath), options);
+        return OpenArchive(new FileInfo(filePath), options);
     }
 
-    /// <summary>
-    /// Opens an Archive from a filepath asynchronously.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="options"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
+    public static ValueTask<IAsyncArchive> OpenAsyncArchive(
         string filePath,
         ReaderOptions? options = null,
         CancellationToken cancellationToken = default
     )
     {
         filePath.NotNullOrEmpty(nameof(filePath));
-        return OpenAsync(new FileInfo(filePath), options, cancellationToken);
+        return OpenAsyncArchive(new FileInfo(filePath), options, cancellationToken);
     }
 
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="options"></param>
-    public static IArchive Open(FileInfo fileInfo, ReaderOptions? options = null)
+    public static IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? options = null)
     {
         options ??= new ReaderOptions { LeaveStreamOpen = false };
 
-        return FindFactory<IArchiveFactory>(fileInfo).Open(fileInfo, options);
+        return FindFactory<IArchiveFactory>(fileInfo).OpenArchive(fileInfo, options);
     }
 
-    /// <summary>
-    /// Opens an Archive from a FileInfo object asynchronously.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="options"></param>
-    /// <param name="cancellationToken"></param>
-    public static async ValueTask<IAsyncArchive> OpenAsync(
+    public static async ValueTask<IAsyncArchive> OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? options = null,
         CancellationToken cancellationToken = default
@@ -115,17 +77,14 @@ public static class ArchiveFactory
     {
         options ??= new ReaderOptions { LeaveStreamOpen = false };
 
-        var factory = await FindFactoryAsync<IArchiveFactory>(fileInfo, cancellationToken)
-            .ConfigureAwait(false);
-        return await factory.OpenAsync(fileInfo, options, cancellationToken).ConfigureAwait(false);
+        var factory = await FindFactoryAsync<IArchiveFactory>(fileInfo, cancellationToken);
+        return factory.OpenAsyncArchive(fileInfo, options, cancellationToken);
     }
 
-    /// <summary>
-    /// Constructor with IEnumerable FileInfo objects, multi and split support.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="options"></param>
-    public static IArchive Open(IEnumerable<FileInfo> fileInfos, ReaderOptions? options = null)
+    public static IArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? options = null
+    )
     {
         fileInfos.NotNull(nameof(fileInfos));
         var filesArray = fileInfos.ToArray();
@@ -137,22 +96,16 @@ public static class ArchiveFactory
         var fileInfo = filesArray[0];
         if (filesArray.Length == 1)
         {
-            return Open(fileInfo, options);
+            return OpenArchive(fileInfo, options);
         }
 
         fileInfo.NotNull(nameof(fileInfo));
         options ??= new ReaderOptions { LeaveStreamOpen = false };
 
-        return FindFactory<IMultiArchiveFactory>(fileInfo).Open(filesArray, options);
+        return FindFactory<IMultiArchiveFactory>(fileInfo).OpenArchive(filesArray, options);
     }
 
-    /// <summary>
-    /// Opens a multi-part archive from files asynchronously.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="options"></param>
-    /// <param name="cancellationToken"></param>
-    public static async ValueTask<IAsyncArchive> OpenAsync(
+    public static async ValueTask<IAsyncArchive> OpenAsyncArchive(
         IEnumerable<FileInfo> fileInfos,
         ReaderOptions? options = null,
         CancellationToken cancellationToken = default
@@ -168,24 +121,17 @@ public static class ArchiveFactory
         var fileInfo = filesArray[0];
         if (filesArray.Length == 1)
         {
-            return await OpenAsync(fileInfo, options, cancellationToken).ConfigureAwait(false);
+            return await OpenAsyncArchive(fileInfo, options, cancellationToken);
         }
 
         fileInfo.NotNull(nameof(fileInfo));
         options ??= new ReaderOptions { LeaveStreamOpen = false };
 
-        var factory = FindFactory<IMultiArchiveFactory>(fileInfo);
-        return await factory
-            .OpenAsync(filesArray, options, cancellationToken)
-            .ConfigureAwait(false);
+        var factory = await FindFactoryAsync<IMultiArchiveFactory>(fileInfo, cancellationToken);
+        return factory.OpenAsyncArchive(filesArray, options, cancellationToken);
     }
 
-    /// <summary>
-    /// Constructor with IEnumerable FileInfo objects, multi and split support.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="options"></param>
-    public static IArchive Open(IEnumerable<Stream> streams, ReaderOptions? options = null)
+    public static IArchive OpenArchive(IEnumerable<Stream> streams, ReaderOptions? options = null)
     {
         streams.NotNull(nameof(streams));
         var streamsArray = streams.ToArray();
@@ -197,22 +143,16 @@ public static class ArchiveFactory
         var firstStream = streamsArray[0];
         if (streamsArray.Length == 1)
         {
-            return Open(firstStream, options);
+            return OpenArchive(firstStream, options);
         }
 
         firstStream.NotNull(nameof(firstStream));
         options ??= new ReaderOptions();
 
-        return FindFactory<IMultiArchiveFactory>(firstStream).Open(streamsArray, options);
+        return FindFactory<IMultiArchiveFactory>(firstStream).OpenArchive(streamsArray, options);
     }
 
-    /// <summary>
-    /// Opens a multi-part archive from streams asynchronously.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="options"></param>
-    /// <param name="cancellationToken"></param>
-    public static async ValueTask<IAsyncArchive> OpenAsync(
+    public static async ValueTask<IAsyncArchive> OpenAsyncArchive(
         IEnumerable<Stream> streams,
         ReaderOptions? options = null,
         CancellationToken cancellationToken = default
@@ -229,28 +169,23 @@ public static class ArchiveFactory
         var firstStream = streamsArray[0];
         if (streamsArray.Length == 1)
         {
-            return await OpenAsync(firstStream, options, cancellationToken).ConfigureAwait(false);
+            return await OpenAsyncArchive(firstStream, options, cancellationToken);
         }
 
         firstStream.NotNull(nameof(firstStream));
         options ??= new ReaderOptions();
 
         var factory = FindFactory<IMultiArchiveFactory>(firstStream);
-        return await factory
-            .OpenAsync(streamsArray, options, cancellationToken)
-            .ConfigureAwait(false);
+        return factory.OpenAsyncArchive(streamsArray, options);
     }
 
-    /// <summary>
-    /// Extract to specific directory, retaining filename
-    /// </summary>
     public static void WriteToDirectory(
         string sourceArchive,
         string destinationDirectory,
         ExtractionOptions? options = null
     )
     {
-        using var archive = Open(sourceArchive);
+        using var archive = OpenArchive(sourceArchive);
         archive.WriteToDirectory(destinationDirectory, options);
     }
 
@@ -382,22 +317,12 @@ public static class ArchiveFactory
         return false;
     }
 
-    /// <summary>
-    /// From a passed in archive (zip, rar, 7z, 001), return all parts.
-    /// </summary>
-    /// <param name="part1"></param>
-    /// <returns></returns>
     public static IEnumerable<string> GetFileParts(string part1)
     {
         part1.NotNullOrEmpty(nameof(part1));
         return GetFileParts(new FileInfo(part1)).Select(a => a.FullName);
     }
 
-    /// <summary>
-    /// From a passed in archive (zip, rar, 7z, 001), return all parts.
-    /// </summary>
-    /// <param name="part1"></param>
-    /// <returns></returns>
     public static IEnumerable<FileInfo> GetFileParts(FileInfo part1)
     {
         part1.NotNull(nameof(part1));
@@ -411,7 +336,7 @@ public static class ArchiveFactory
             if (part != null)
             {
                 yield return part;
-                while ((part = factory.GetFilePart(i++, part1)) != null) //tests split too
+                while ((part = factory.GetFilePart(i++, part1)) != null)
                 {
                     yield return part;
                 }

src/SharpCompress/Archives/AutoArchiveFactory.cs

@@ -31,21 +31,22 @@ internal class AutoArchiveFactory : IArchiveFactory
 
     public FileInfo? GetFilePart(int index, FileInfo part1) => throw new NotSupportedException();
 
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        ArchiveFactory.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        ArchiveFactory.OpenArchive(stream, readerOptions);
 
-    public async ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => await ArchiveFactory.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        ArchiveFactory.Open(fileInfo, readerOptions);
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        ArchiveFactory.OpenArchive(fileInfo, readerOptions);
 
-    public async ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => await ArchiveFactory.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 }

src/SharpCompress/Archives/GZip/GZipArchive.Factory.cs

@@ -0,0 +1,197 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Common.GZip;
+using SharpCompress.IO;
+using SharpCompress.Readers;
+using SharpCompress.Readers.GZip;
+using SharpCompress.Writers;
+using SharpCompress.Writers.GZip;
+
+namespace SharpCompress.Archives.GZip;
+
+public partial class GZipArchive
+#if NET8_0_OR_GREATER
+    : IWritableArchiveOpenable,
+        IMultiArchiveOpenable<IWritableArchive, IWritableAsyncArchive>
+#endif
+{
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        path.NotNullOrEmpty(nameof(path));
+        return (IWritableAsyncArchive)OpenArchive(
+            new FileInfo(path),
+            readerOptions ?? new ReaderOptions()
+        );
+    }
+
+    public static IWritableArchive OpenArchive(string filePath, ReaderOptions? readerOptions = null)
+    {
+        filePath.NotNullOrEmpty(nameof(filePath));
+        return OpenArchive(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
+    }
+
+    public static IWritableArchive OpenArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfo.NotNull(nameof(fileInfo));
+        return new GZipArchive(
+            new SourceStream(
+                fileInfo,
+                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfos.NotNull(nameof(fileInfos));
+        var files = fileInfos.ToArray();
+        return new GZipArchive(
+            new SourceStream(
+                files[0],
+                i => i < files.Length ? files[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        streams.NotNull(nameof(streams));
+        var strms = streams.ToArray();
+        return new GZipArchive(
+            new SourceStream(
+                strms[0],
+                i => i < strms.Length ? strms[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null)
+    {
+        stream.NotNull(nameof(stream));
+
+        if (stream is not { CanSeek: true })
+        {
+            throw new ArgumentException("Stream must be seekable", nameof(stream));
+        }
+
+        return new GZipArchive(
+            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
+        );
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(stream, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(streams, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
+
+    public static IWritableArchive CreateArchive() => new GZipArchive();
+
+    public static IWritableAsyncArchive CreateAsyncArchive() => new GZipArchive();
+
+    public static bool IsGZipFile(string filePath) => IsGZipFile(new FileInfo(filePath));
+
+    public static bool IsGZipFile(FileInfo fileInfo)
+    {
+        if (!fileInfo.Exists)
+        {
+            return false;
+        }
+
+        using Stream stream = fileInfo.OpenRead();
+        return IsGZipFile(stream);
+    }
+
+    public static bool IsGZipFile(Stream stream)
+    {
+        Span<byte> header = stackalloc byte[10];
+
+        if (!stream.ReadFully(header))
+        {
+            return false;
+        }
+
+        if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
+        {
+            return false;
+        }
+
+        return true;
+    }
+
+    public static async ValueTask<bool> IsGZipFileAsync(
+        Stream stream,
+        CancellationToken cancellationToken = default
+    )
+    {
+        byte[] header = new byte[10];
+
+        if (!await stream.ReadFullyAsync(header, cancellationToken).ConfigureAwait(false))
+        {
+            return false;
+        }
+
+        if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
+        {
+            return false;
+        }
+
+        return true;
+    }
+}

src/SharpCompress/Archives/GZip/GZipArchive.cs

@@ -14,186 +14,20 @@ using SharpCompress.Writers.GZip;
 
 namespace SharpCompress.Archives.GZip;
 
-public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
+public partial class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
 {
-    /// <summary>
-    /// Constructor expects a filepath to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="readerOptions"></param>
-    public static GZipArchive Open(string filePath, ReaderOptions? readerOptions = null)
-    {
-        filePath.NotNullOrEmpty(nameof(filePath));
-        return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
-    }
-
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    public static GZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
-    {
-        fileInfo.NotNull(nameof(fileInfo));
-        return new GZipArchive(
-            new SourceStream(
-                fileInfo,
-                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all file parts passed in
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    public static GZipArchive Open(
-        IEnumerable<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        fileInfos.NotNull(nameof(fileInfos));
-        var files = fileInfos.ToArray();
-        return new GZipArchive(
-            new SourceStream(
-                files[0],
-                i => i < files.Length ? files[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all stream parts passed in
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    public static GZipArchive Open(IEnumerable<Stream> streams, ReaderOptions? readerOptions = null)
-    {
-        streams.NotNull(nameof(streams));
-        var strms = streams.ToArray();
-        return new GZipArchive(
-            new SourceStream(
-                strms[0],
-                i => i < strms.Length ? strms[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Takes a seekable Stream as a source
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    public static GZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
-    {
-        stream.NotNull(nameof(stream));
-
-        if (stream is not { CanSeek: true })
-        {
-            throw new ArgumentException("Stream must be seekable", nameof(stream));
-        }
-
-        return new GZipArchive(
-            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
-        );
-    }
-
-    /// <summary>
-    /// Opens a GZipArchive asynchronously from a stream.
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a GZipArchive asynchronously from a FileInfo.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        FileInfo fileInfo,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfo, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a GZipArchive asynchronously from multiple streams.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(streams, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a GZipArchive asynchronously from multiple FileInfo objects.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfos, readerOptions));
-    }
-
-    public static GZipArchive Create() => new();
-
-    /// <summary>
-    /// Constructor with a SourceStream able to handle FileInfo and Streams.
-    /// </summary>
-    /// <param name="sourceStream"></param>
     private GZipArchive(SourceStream sourceStream)
         : base(ArchiveType.GZip, sourceStream) { }
 
+    internal GZipArchive()
+        : base(ArchiveType.GZip) { }
+
     protected override IEnumerable<GZipVolume> LoadVolumes(SourceStream sourceStream)
     {
         sourceStream.LoadAllParts();
         return sourceStream.Streams.Select(a => new GZipVolume(a, ReaderOptions, 0));
     }
 
-    public static bool IsGZipFile(string filePath) => IsGZipFile(new FileInfo(filePath));
-
-    public static bool IsGZipFile(FileInfo fileInfo)
-    {
-        if (!fileInfo.Exists)
-        {
-            return false;
-        }
-
-        using Stream stream = fileInfo.OpenRead();
-        return IsGZipFile(stream);
-    }
-
     public void SaveTo(string filePath) => SaveTo(new FileInfo(filePath));
 
     public void SaveTo(FileInfo fileInfo)
@@ -215,50 +49,6 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
             .ConfigureAwait(false);
     }
 
-    public static bool IsGZipFile(Stream stream)
-    {
-        // read the header on the first read
-        Span<byte> header = stackalloc byte[10];
-
-        // workitem 8501: handle edge case (decompress empty stream)
-        if (!stream.ReadFully(header))
-        {
-            return false;
-        }
-
-        if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
-        {
-            return false;
-        }
-
-        return true;
-    }
-
-    public static async ValueTask<bool> IsGZipFileAsync(
-        Stream stream,
-        CancellationToken cancellationToken = default
-    )
-    {
-        // read the header on the first read
-        byte[] header = new byte[10];
-
-        // workitem 8501: handle edge case (decompress empty stream)
-        if (!await stream.ReadFullyAsync(header, cancellationToken).ConfigureAwait(false))
-        {
-            return false;
-        }
-
-        if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
-        {
-            return false;
-        }
-
-        return true;
-    }
-
-    internal GZipArchive()
-        : base(ArchiveType.GZip) { }
-
     protected override GZipArchiveEntry CreateEntryInternal(
         string filePath,
         Stream source,
@@ -329,7 +119,18 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
         var stream = volumes.Single().Stream;
         yield return new GZipArchiveEntry(
             this,
-            new GZipFilePart(stream, ReaderOptions.ArchiveEncoding)
+            GZipFilePart.Create(stream, ReaderOptions.ArchiveEncoding)
+        );
+    }
+
+    protected override async IAsyncEnumerable<GZipArchiveEntry> LoadEntriesAsync(
+        IAsyncEnumerable<GZipVolume> volumes
+    )
+    {
+        var stream = (await volumes.SingleAsync()).Stream;
+        yield return new GZipArchiveEntry(
+            this,
+            await GZipFilePart.CreateAsync(stream, ReaderOptions.ArchiveEncoding)
         );
     }
 
@@ -337,13 +138,13 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
     {
         var stream = Volumes.Single().Stream;
         stream.Position = 0;
-        return GZipReader.Open(stream);
+        return GZipReader.OpenReader(stream);
     }
 
     protected override ValueTask<IAsyncReader> CreateReaderForSolidExtractionAsync()
     {
         var stream = Volumes.Single().Stream;
         stream.Position = 0;
-        return new(GZipReader.Open(stream));
+        return new((IAsyncReader)GZipReader.OpenReader(stream));
     }
 }

src/SharpCompress/Archives/GZip/GZipArchiveEntry.cs

@@ -23,12 +23,10 @@ public class GZipArchiveEntry : GZipEntry, IArchiveEntry
         return Parts.Single().GetCompressedStream().NotNull();
     }
 
-    public async ValueTask<Stream> OpenEntryStreamAsync(
-        CancellationToken cancellationToken = default
-    )
+    public ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
     {
         // GZip synchronous implementation is fast enough, just wrap it
-        return OpenEntryStream();
+        return new(OpenEntryStream());
     }
 
     #region IArchiveEntry Members

src/SharpCompress/Archives/IArchive.cs

@@ -38,5 +38,18 @@ public interface IArchive : IDisposable
     /// <summary>
     /// The total size of the files as uncompressed in the archive.
     /// </summary>
-    long TotalUncompressSize { get; }
+    long TotalUncompressedSize { get; }
+
+    /// <summary>
+    /// Returns whether the archive is encrypted.
+    /// </summary>
+    bool IsEncrypted { get; }
+
+    /// <summary>
+    /// Returns whether multi-threaded extraction is supported for this archive.
+    /// Multi-threading is supported when the archive is opened from a FileInfo or file path
+    /// (not a stream) and the format supports random access (e.g., Zip, Tar, Rar).
+    /// SOLID archives (some Rar, all 7Zip) should use sequential extraction for best performance.
+    /// </summary>
+    bool SupportsMultiThreadedExtraction { get; }
 }

src/SharpCompress/Archives/IArchiveExtensions.cs

@@ -8,7 +8,6 @@ namespace SharpCompress.Archives;
 
 public static class IArchiveExtensions
 {
-    /// <param name="archive">The archive to extract.</param>
     extension(IArchive archive)
     {
         /// <summary>
@@ -23,7 +22,6 @@ public static class IArchiveExtensions
             IProgress<ProgressReport>? progress = null
         )
         {
-            // For solid archives (Rar, 7Zip), use the optimized reader-based approach
             if (archive.IsSolid || archive.Type == ArchiveType.SevenZip)
             {
                 using var reader = archive.ExtractAllEntries();
@@ -31,7 +29,6 @@ public static class IArchiveExtensions
             }
             else
             {
-                // For non-solid archives, extract entries directly
                 archive.WriteToDirectoryInternal(destinationDirectory, options, progress);
             }
         }
@@ -42,14 +39,10 @@ public static class IArchiveExtensions
             IProgress<ProgressReport>? progress
         )
         {
-            // Prepare for progress reporting
-            var totalBytes = archive.TotalUncompressSize;
+            var totalBytes = archive.TotalUncompressedSize;
             var bytesRead = 0L;
-
-            // Tracking for created directories.
             var seenDirectories = new HashSet<string>();
 
-            // Extract
             foreach (var entry in archive.Entries)
             {
                 if (entry.IsDirectory)
@@ -68,10 +61,8 @@ public static class IArchiveExtensions
                     continue;
                 }
 
-                // Use the entry's WriteToDirectory method which respects ExtractionOptions
                 entry.WriteToDirectory(destinationDirectory, options);
 
-                // Update progress
                 bytesRead += entry.Size;
                 progress?.Report(
                     new ProgressReport(entry.Key ?? string.Empty, bytesRead, totalBytes)

src/SharpCompress/Archives/IArchiveFactory.cs

@@ -1,6 +1,5 @@
 using System.IO;
 using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Factories;
 using SharpCompress.Readers;
 
@@ -26,26 +25,21 @@ public interface IArchiveFactory : IFactory
     /// </summary>
     /// <param name="stream">An open, readable and seekable stream.</param>
     /// <param name="readerOptions">reading options.</param>
-    IArchive Open(Stream stream, ReaderOptions? readerOptions = null);
+    IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null);
 
     /// <summary>
     /// Opens an Archive for random access asynchronously.
     /// </summary>
     /// <param name="stream">An open, readable and seekable stream.</param>
     /// <param name="readerOptions">reading options.</param>
-    /// <param name="cancellationToken">Cancellation token.</param>
-    ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    );
+    IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null);
 
     /// <summary>
     /// Constructor with a FileInfo object to an existing file.
     /// </summary>
     /// <param name="fileInfo">the file to open.</param>
     /// <param name="readerOptions">reading options.</param>
-    IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null);
+    IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null);
 
     /// <summary>
     /// Opens an Archive from a FileInfo object asynchronously.
@@ -53,7 +47,7 @@ public interface IArchiveFactory : IFactory
     /// <param name="fileInfo">the file to open.</param>
     /// <param name="readerOptions">reading options.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    ValueTask<IAsyncArchive> OpenAsync(
+    IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default

src/SharpCompress/Archives/IArchiveOpenable.cs

@@ -0,0 +1,40 @@
+#if NET8_0_OR_GREATER
+using System.IO;
+using System.Threading;
+using SharpCompress.Readers;
+
+namespace SharpCompress.Archives;
+
+public interface IArchiveOpenable<TSync, TASync>
+    where TSync : IArchive
+    where TASync : IAsyncArchive
+{
+    public static abstract TSync OpenArchive(string filePath, ReaderOptions? readerOptions = null);
+
+    public static abstract TSync OpenArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null
+    );
+
+    public static abstract TSync OpenArchive(Stream stream, ReaderOptions? readerOptions = null);
+
+    public static abstract TASync OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    );
+
+    public static abstract TASync OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    );
+
+    public static abstract TASync OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    );
+}
+
+#endif

src/SharpCompress/Archives/IAsyncArchive.cs

@@ -39,5 +39,10 @@ public interface IAsyncArchive : IAsyncDisposable
     /// <summary>
     /// The total size of the files as uncompressed in the archive.
     /// </summary>
-    ValueTask<long> TotalUncompressSizeAsync();
+    ValueTask<long> TotalUncompressedSizeAsync();
+
+    /// <summary>
+    /// Returns whether the archive is encrypted.
+    /// </summary>
+    ValueTask<bool> IsEncryptedAsync();
 }

src/SharpCompress/Archives/IAsyncArchiveExtensions.cs

@@ -10,84 +10,83 @@ namespace SharpCompress.Archives;
 
 public static class IAsyncArchiveExtensions
 {
-    /// <summary>
-    /// Extract to specific directory asynchronously with progress reporting and cancellation support
-    /// </summary>
-    /// <param name="archive">The archive to extract.</param>
-    /// <param name="destinationDirectory">The folder to extract into.</param>
-    /// <param name="options">Extraction options.</param>
-    /// <param name="progress">Optional progress reporter for tracking extraction progress.</param>
-    /// <param name="cancellationToken">Optional cancellation token.</param>
-    public static async Task WriteToDirectoryAsync(
-        this IAsyncArchive archive,
-        string destinationDirectory,
-        ExtractionOptions? options = null,
-        IProgress<ProgressReport>? progress = null,
-        CancellationToken cancellationToken = default
-    )
+    extension(IAsyncArchive archive)
     {
-        // For solid archives (Rar, 7Zip), use the optimized reader-based approach
-        if (await archive.IsSolidAsync() || archive.Type == ArchiveType.SevenZip)
+        /// <summary>
+        /// Extract to specific directory asynchronously with progress reporting and cancellation support
+        /// </summary>
+        /// <param name="archive">The archive to extract.</param>
+        /// <param name="destinationDirectory">The folder to extract into.</param>
+        /// <param name="options">Extraction options.</param>
+        /// <param name="progress">Optional progress reporter for tracking extraction progress.</param>
+        /// <param name="cancellationToken">Optional cancellation token.</param>
+        public async Task WriteToDirectoryAsync(
+            string destinationDirectory,
+            ExtractionOptions? options = null,
+            IProgress<ProgressReport>? progress = null,
+            CancellationToken cancellationToken = default
+        )
         {
-            await using var reader = await archive.ExtractAllEntriesAsync();
-            await reader.WriteAllToDirectoryAsync(destinationDirectory, options, cancellationToken);
-        }
-        else
-        {
-            // For non-solid archives, extract entries directly
-            await archive.WriteToDirectoryAsyncInternal(
-                destinationDirectory,
-                options,
-                progress,
-                cancellationToken
-            );
-        }
-    }
-
-    private static async Task WriteToDirectoryAsyncInternal(
-        this IAsyncArchive archive,
-        string destinationDirectory,
-        ExtractionOptions? options,
-        IProgress<ProgressReport>? progress,
-        CancellationToken cancellationToken
-    )
-    {
-        // Prepare for progress reporting
-        var totalBytes = await archive.TotalUncompressSizeAsync();
-        var bytesRead = 0L;
-
-        // Tracking for created directories.
-        var seenDirectories = new HashSet<string>();
-
-        // Extract
-        await foreach (var entry in archive.EntriesAsync.WithCancellation(cancellationToken))
-        {
-            cancellationToken.ThrowIfCancellationRequested();
-
-            if (entry.IsDirectory)
+            if (await archive.IsSolidAsync() || archive.Type == ArchiveType.SevenZip)
             {
-                var dirPath = Path.Combine(
+                await using var reader = await archive.ExtractAllEntriesAsync();
+                await reader.WriteAllToDirectoryAsync(
                     destinationDirectory,
-                    entry.Key.NotNull("Entry Key is null")
+                    options,
+                    cancellationToken
                 );
-                if (
-                    Path.GetDirectoryName(dirPath + "/") is { } parentDirectory
-                    && seenDirectories.Add(dirPath)
-                )
-                {
-                    Directory.CreateDirectory(parentDirectory);
-                }
-                continue;
             }
+            else
+            {
+                await archive.WriteToDirectoryAsyncInternal(
+                    destinationDirectory,
+                    options,
+                    progress,
+                    cancellationToken
+                );
+            }
+        }
 
-            // Use the entry's WriteToDirectoryAsync method which respects ExtractionOptions
-            await entry
-                .WriteToDirectoryAsync(destinationDirectory, options, cancellationToken)
-                .ConfigureAwait(false);
+        private async Task WriteToDirectoryAsyncInternal(
+            string destinationDirectory,
+            ExtractionOptions? options,
+            IProgress<ProgressReport>? progress,
+            CancellationToken cancellationToken
+        )
+        {
+            var totalBytes = await archive.TotalUncompressedSizeAsync();
+            var bytesRead = 0L;
+            var seenDirectories = new HashSet<string>();
 
-            // Update progress
-            bytesRead += entry.Size;
-            progress?.Report(new ProgressReport(entry.Key ?? string.Empty, bytesRead, totalBytes));
+            await foreach (var entry in archive.EntriesAsync.WithCancellation(cancellationToken))
+            {
+                cancellationToken.ThrowIfCancellationRequested();
+
+                if (entry.IsDirectory)
+                {
+                    var dirPath = Path.Combine(
+                        destinationDirectory,
+                        entry.Key.NotNull("Entry Key is null")
+                    );
+                    if (
+                        Path.GetDirectoryName(dirPath + "/") is { } parentDirectory
+                        && seenDirectories.Add(dirPath)
+                    )
+                    {
+                        Directory.CreateDirectory(parentDirectory);
+                    }
+                    continue;
+                }
+
+                await entry
+                    .WriteToDirectoryAsync(destinationDirectory, options, cancellationToken)
+                    .ConfigureAwait(false);
+
+                bytesRead += entry.Size;
+                progress?.Report(
+                    new ProgressReport(entry.Key ?? string.Empty, bytesRead, totalBytes)
+                );
+            }
         }
     }
 }

src/SharpCompress/Archives/IMultiArchiveFactory.cs

@@ -1,7 +1,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Factories;
 using SharpCompress.Readers;
 
@@ -27,18 +26,16 @@ public interface IMultiArchiveFactory : IFactory
     /// </summary>
     /// <param name="streams"></param>
     /// <param name="readerOptions">reading options.</param>
-    IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null);
+    IArchive OpenArchive(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null);
 
     /// <summary>
     /// Opens a multi-part archive from streams asynchronously.
     /// </summary>
     /// <param name="streams"></param>
     /// <param name="readerOptions">reading options.</param>
-    /// <param name="cancellationToken">Cancellation token.</param>
-    ValueTask<IAsyncArchive> OpenAsync(
+    IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
+        ReaderOptions? readerOptions = null
     );
 
     /// <summary>
@@ -46,7 +43,7 @@ public interface IMultiArchiveFactory : IFactory
     /// </summary>
     /// <param name="fileInfos"></param>
     /// <param name="readerOptions">reading options.</param>
-    IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null);
+    IArchive OpenArchive(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null);
 
     /// <summary>
     /// Opens a multi-part archive from files asynchronously.
@@ -54,7 +51,7 @@ public interface IMultiArchiveFactory : IFactory
     /// <param name="fileInfos"></param>
     /// <param name="readerOptions">reading options.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
-    ValueTask<IAsyncArchive> OpenAsync(
+    IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default

src/SharpCompress/Archives/IMultiArchiveOpenable.cs

@@ -0,0 +1,35 @@
+#if NET8_0_OR_GREATER
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using SharpCompress.Readers;
+
+namespace SharpCompress.Archives;
+
+public interface IMultiArchiveOpenable<TSync, TASync>
+    where TSync : IArchive
+    where TASync : IAsyncArchive
+{
+    public static abstract TSync OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    );
+
+    public static abstract TSync OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    );
+
+    public static abstract TASync OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    );
+
+    public static abstract TASync OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    );
+}
+#endif

src/SharpCompress/Archives/IWritableArchive.cs

@@ -6,8 +6,17 @@ using SharpCompress.Writers;
 
 namespace SharpCompress.Archives;
 
-public interface IWritableArchive : IArchive
+public interface IWritableArchiveCommon
 {
+    /// <summary>
+    /// Use this to pause entry rebuilding when adding large collections of entries.  Dispose when complete.  A  using statement is recommended.
+    /// </summary>
+    /// <returns>IDisposeable to resume entry rebuilding</returns>
+    IDisposable PauseEntryRebuilding();
+
+    /// <summary>
+    /// Removes the specified entry from the archive.
+    /// </summary>
     void RemoveEntry(IArchiveEntry entry);
 
     IArchiveEntry AddEntry(
@@ -19,18 +28,24 @@ public interface IWritableArchive : IArchive
     );
 
     IArchiveEntry AddDirectoryEntry(string key, DateTime? modified = null);
+}
 
+public interface IWritableArchive : IArchive, IWritableArchiveCommon
+{
+    /// <summary>
+    /// Saves the archive to the specified stream using the given writer options.
+    /// </summary>
     void SaveTo(Stream stream, WriterOptions options);
+}
 
+public interface IWritableAsyncArchive : IAsyncArchive, IWritableArchiveCommon
+{
+    /// <summary>
+    /// Asynchronously saves the archive to the specified stream using the given writer options.
+    /// </summary>
     ValueTask SaveToAsync(
         Stream stream,
         WriterOptions options,
         CancellationToken cancellationToken = default
     );
-
-    /// <summary>
-    /// Use this to pause entry rebuilding when adding large collections of entries.  Dispose when complete.  A  using statement is recommended.
-    /// </summary>
-    /// <returns>IDisposeable to resume entry rebuilding</returns>
-    IDisposable PauseEntryRebuilding();
 }

src/SharpCompress/Archives/IWritableArchiveCommonExtensions.cs

@@ -0,0 +1,59 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Archives;
+
+public static class IWritableArchiveCommonExtensions
+{
+    extension(IWritableArchiveCommon writableArchive)
+    {
+        public void AddAllFromDirectory(
+            string filePath,
+            string searchPattern = "*.*",
+            SearchOption searchOption = SearchOption.AllDirectories
+        )
+        {
+            using (writableArchive.PauseEntryRebuilding())
+            {
+                foreach (
+                    var path in Directory.EnumerateFiles(filePath, searchPattern, searchOption)
+                )
+                {
+                    var fileInfo = new FileInfo(path);
+                    writableArchive.AddEntry(
+                        path.Substring(filePath.Length),
+                        fileInfo.OpenRead(),
+                        true,
+                        fileInfo.Length,
+                        fileInfo.LastWriteTime
+                    );
+                }
+            }
+        }
+
+        public IArchiveEntry AddEntry(string key, string file) =>
+            writableArchive.AddEntry(key, new FileInfo(file));
+
+        public IArchiveEntry AddEntry(
+            string key,
+            Stream source,
+            long size = 0,
+            DateTime? modified = null
+        ) => writableArchive.AddEntry(key, source, false, size, modified);
+
+        public IArchiveEntry AddEntry(string key, FileInfo fileInfo)
+        {
+            if (!fileInfo.Exists)
+            {
+                throw new ArgumentException("FileInfo does not exist.");
+            }
+            return writableArchive.AddEntry(
+                key,
+                fileInfo.OpenRead(),
+                true,
+                fileInfo.Length,
+                fileInfo.LastWriteTime
+            );
+        }
+    }
+}

src/SharpCompress/Archives/IWritableArchiveExtensions.cs

@@ -1,106 +1,20 @@
-using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
+using SharpCompress.Common;
 using SharpCompress.Writers;
 
 namespace SharpCompress.Archives;
 
 public static class IWritableArchiveExtensions
 {
-    public static void AddEntry(
-        this IWritableArchive writableArchive,
-        string entryPath,
-        string filePath
-    )
+    extension(IWritableArchive writableArchive)
     {
-        var fileInfo = new FileInfo(filePath);
-        if (!fileInfo.Exists)
+        public void SaveTo(string filePath, WriterOptions? options = null) =>
+            writableArchive.SaveTo(new FileInfo(filePath), options ?? new(CompressionType.Deflate));
+
+        public void SaveTo(FileInfo fileInfo, WriterOptions? options = null)
         {
-            throw new FileNotFoundException("Could not AddEntry: " + filePath);
+            using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
+            writableArchive.SaveTo(stream, options ?? new(CompressionType.Deflate));
         }
-        writableArchive.AddEntry(
-            entryPath,
-            new FileInfo(filePath).OpenRead(),
-            true,
-            fileInfo.Length,
-            fileInfo.LastWriteTime
-        );
-    }
-
-    public static void SaveTo(
-        this IWritableArchive writableArchive,
-        string filePath,
-        WriterOptions options
-    ) => writableArchive.SaveTo(new FileInfo(filePath), options);
-
-    public static void SaveTo(
-        this IWritableArchive writableArchive,
-        FileInfo fileInfo,
-        WriterOptions options
-    )
-    {
-        using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
-        writableArchive.SaveTo(stream, options);
-    }
-
-    public static ValueTask SaveToAsync(
-        this IWritableArchive writableArchive,
-        string filePath,
-        WriterOptions options,
-        CancellationToken cancellationToken = default
-    ) => writableArchive.SaveToAsync(new FileInfo(filePath), options, cancellationToken);
-
-    public static async ValueTask SaveToAsync(
-        this IWritableArchive writableArchive,
-        FileInfo fileInfo,
-        WriterOptions options,
-        CancellationToken cancellationToken = default
-    )
-    {
-        using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
-        await writableArchive.SaveToAsync(stream, options, cancellationToken).ConfigureAwait(false);
-    }
-
-    public static void AddAllFromDirectory(
-        this IWritableArchive writableArchive,
-        string filePath,
-        string searchPattern = "*.*",
-        SearchOption searchOption = SearchOption.AllDirectories
-    )
-    {
-        using (writableArchive.PauseEntryRebuilding())
-        {
-            foreach (var path in Directory.EnumerateFiles(filePath, searchPattern, searchOption))
-            {
-                var fileInfo = new FileInfo(path);
-                writableArchive.AddEntry(
-                    path.Substring(filePath.Length),
-                    fileInfo.OpenRead(),
-                    true,
-                    fileInfo.Length,
-                    fileInfo.LastWriteTime
-                );
-            }
-        }
-    }
-
-    public static IArchiveEntry AddEntry(
-        this IWritableArchive writableArchive,
-        string key,
-        FileInfo fileInfo
-    )
-    {
-        if (!fileInfo.Exists)
-        {
-            throw new ArgumentException("FileInfo does not exist.");
-        }
-        return writableArchive.AddEntry(
-            key,
-            fileInfo.OpenRead(),
-            true,
-            fileInfo.Length,
-            fileInfo.LastWriteTime
-        );
     }
 }

src/SharpCompress/Archives/IWritableArchiveOpenable.cs

@@ -0,0 +1,10 @@
+#if NET8_0_OR_GREATER
+namespace SharpCompress.Archives;
+
+public interface IWritableArchiveOpenable
+    : IArchiveOpenable<IWritableArchive, IWritableAsyncArchive>
+{
+    public static abstract IWritableArchive CreateArchive();
+    public static abstract IWritableAsyncArchive CreateAsyncArchive();
+}
+#endif

src/SharpCompress/Archives/IWritableAsyncArchiveExtensions.cs

@@ -0,0 +1,36 @@
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Writers;
+
+namespace SharpCompress.Archives;
+
+public static class IWritableAsyncArchiveExtensions
+{
+    extension(IWritableAsyncArchive writableArchive)
+    {
+        public ValueTask SaveToAsync(
+            string filePath,
+            WriterOptions? options = null,
+            CancellationToken cancellationToken = default
+        ) =>
+            writableArchive.SaveToAsync(
+                new FileInfo(filePath),
+                options ?? new(CompressionType.Deflate),
+                cancellationToken
+            );
+
+        public async ValueTask SaveToAsync(
+            FileInfo fileInfo,
+            WriterOptions? options = null,
+            CancellationToken cancellationToken = default
+        )
+        {
+            using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
+            await writableArchive
+                .SaveToAsync(stream, options ?? new(CompressionType.Deflate), cancellationToken)
+                .ConfigureAwait(false);
+        }
+    }
+}

src/SharpCompress/Archives/IWriteableArchiveFactory.cs

@@ -16,5 +16,5 @@ public interface IWriteableArchiveFactory : Factories.IFactory
     /// Creates a new, empty archive, ready to be written.
     /// </summary>
     /// <returns></returns>
-    IWritableArchive CreateWriteableArchive();
+    IWritableArchive CreateArchive();
 }

src/SharpCompress/Archives/Rar/RarArchive.Extensions.cs

@@ -1,18 +1,36 @@
-using System.Linq;
+using System.Linq;
+using System.Threading.Tasks;
+using SharpCompress.Common.Rar;
 
 namespace SharpCompress.Archives.Rar;
 
 public static class RarArchiveExtensions
 {
-    /// <summary>
-    /// RarArchive is the first volume of a multi-part archive.  If MultipartVolume is true and IsFirstVolume is false then the first volume file must be missing.
-    /// </summary>
-    public static bool IsFirstVolume(this RarArchive archive) =>
-        archive.Volumes.First().IsFirstVolume;
+    extension(IRarArchive archive)
+    {
+        /// <summary>
+        /// RarArchive is the first volume of a multi-part archive.  If MultipartVolume is true and IsFirstVolume is false then the first volume file must be missing.
+        /// </summary>
+        public bool IsFirstVolume() => archive.Volumes.Cast<RarVolume>().First().IsFirstVolume;
 
-    /// <summary>
-    /// RarArchive is part of a multi-part archive.
-    /// </summary>
-    public static bool IsMultipartVolume(this RarArchive archive) =>
-        archive.Volumes.First().IsMultiVolume;
+        /// <summary>
+        /// RarArchive is part of a multi-part archive.
+        /// </summary>
+        public bool IsMultipartVolume() => archive.Volumes.Cast<RarVolume>().First().IsMultiVolume;
+    }
+
+    extension(IRarAsyncArchive archive)
+    {
+        /// <summary>
+        /// RarArchive is the first volume of a multi-part archive.  If MultipartVolume is true and IsFirstVolume is false then the first volume file must be missing.
+        /// </summary>
+        public async ValueTask<bool> IsFirstVolumeAsync() =>
+            (await archive.VolumesAsync.CastAsync<RarVolume>().FirstAsync()).IsFirstVolume;
+
+        /// <summary>
+        /// RarArchive is part of a multi-part archive.
+        /// </summary>
+        public async ValueTask<bool> IsMultipartVolumeAsync() =>
+            (await archive.VolumesAsync.CastAsync<RarVolume>().FirstAsync()).IsMultiVolume;
+    }
 }

src/SharpCompress/Archives/Rar/RarArchive.Factory.cs

@@ -0,0 +1,166 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using SharpCompress.Common;
+using SharpCompress.Common.Rar;
+using SharpCompress.Common.Rar.Headers;
+using SharpCompress.Compressors.Rar;
+using SharpCompress.IO;
+using SharpCompress.Readers;
+using SharpCompress.Readers.Rar;
+
+namespace SharpCompress.Archives.Rar;
+
+public partial class RarArchive
+#if NET8_0_OR_GREATER
+    : IArchiveOpenable<IRarArchive, IRarAsyncArchive>,
+        IMultiArchiveOpenable<IRarArchive, IRarAsyncArchive>
+#endif
+{
+    public static IRarAsyncArchive OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        path.NotNullOrEmpty(nameof(path));
+        return (IRarAsyncArchive)OpenArchive(new FileInfo(path), readerOptions);
+    }
+
+    public static IRarArchive OpenArchive(string filePath, ReaderOptions? options = null)
+    {
+        filePath.NotNullOrEmpty(nameof(filePath));
+        var fileInfo = new FileInfo(filePath);
+        return new RarArchive(
+            new SourceStream(
+                fileInfo,
+                i => RarArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                options ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IRarArchive OpenArchive(FileInfo fileInfo, ReaderOptions? options = null)
+    {
+        fileInfo.NotNull(nameof(fileInfo));
+        return new RarArchive(
+            new SourceStream(
+                fileInfo,
+                i => RarArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                options ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IRarArchive OpenArchive(Stream stream, ReaderOptions? options = null)
+    {
+        stream.NotNull(nameof(stream));
+
+        if (stream is not { CanSeek: true })
+        {
+            throw new ArgumentException("Stream must be seekable", nameof(stream));
+        }
+
+        return new RarArchive(new SourceStream(stream, _ => null, options ?? new ReaderOptions()));
+    }
+
+    public static IRarArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfos.NotNull(nameof(fileInfos));
+        var files = fileInfos.ToArray();
+        return new RarArchive(
+            new SourceStream(
+                files[0],
+                i => i < files.Length ? files[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IRarArchive OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        streams.NotNull(nameof(streams));
+        var strms = streams.ToArray();
+        return new RarArchive(
+            new SourceStream(
+                strms[0],
+                i => i < strms.Length ? strms[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IRarAsyncArchive OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IRarAsyncArchive)OpenArchive(stream, readerOptions);
+    }
+
+    public static IRarAsyncArchive OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IRarAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
+
+    public static IRarAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IRarAsyncArchive)OpenArchive(streams, readerOptions);
+    }
+
+    public static IRarAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IRarAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
+
+    public static bool IsRarFile(string filePath) => IsRarFile(new FileInfo(filePath));
+
+    public static bool IsRarFile(FileInfo fileInfo)
+    {
+        if (!fileInfo.Exists)
+        {
+            return false;
+        }
+        using Stream stream = fileInfo.OpenRead();
+        return IsRarFile(stream);
+    }
+
+    public static bool IsRarFile(Stream stream, ReaderOptions? options = null)
+    {
+        try
+        {
+            MarkHeader.Read(stream, true, false);
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+}

src/SharpCompress/Archives/Rar/RarArchive.cs

@@ -14,17 +14,23 @@ using SharpCompress.Readers.Rar;
 
 namespace SharpCompress.Archives.Rar;
 
-public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
+public interface IRarArchiveCommon
+{
+    int MinVersion { get; }
+    int MaxVersion { get; }
+}
+
+public interface IRarArchive : IArchive, IRarArchiveCommon { }
+
+public interface IRarAsyncArchive : IAsyncArchive, IRarArchiveCommon { }
+
+public partial class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>, IRarArchive
 {
     private bool _disposed;
     internal Lazy<IRarUnpack> UnpackV2017 { get; } =
         new(() => new Compressors.Rar.UnpackV2017.Unpack());
     internal Lazy<IRarUnpack> UnpackV1 { get; } = new(() => new Compressors.Rar.UnpackV1.Unpack());
 
-    /// <summary>
-    /// Constructor with a SourceStream able to handle FileInfo and Streams.
-    /// </summary>
-    /// <param name="sourceStream"></param>
     private RarArchive(SourceStream sourceStream)
         : base(ArchiveType.Rar, sourceStream) { }
 
@@ -42,15 +48,29 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
         }
     }
 
+    public override async ValueTask DisposeAsync()
+    {
+        if (!_disposed)
+        {
+            if (UnpackV1.IsValueCreated && UnpackV1.Value is IDisposable unpackV1)
+            {
+                unpackV1.Dispose();
+            }
+
+            _disposed = true;
+            await base.DisposeAsync();
+        }
+    }
+
     protected override IEnumerable<RarArchiveEntry> LoadEntries(IEnumerable<RarVolume> volumes) =>
         RarArchiveEntryFactory.GetEntries(this, volumes, ReaderOptions);
 
     protected override IEnumerable<RarVolume> LoadVolumes(SourceStream sourceStream)
     {
-        sourceStream.LoadAllParts(); //request all streams
+        sourceStream.LoadAllParts();
         var streams = sourceStream.Streams.ToArray();
         var i = 0;
-        if (streams.Length > 1 && IsRarFile(streams[1], ReaderOptions)) //test part 2 - true = multipart not split
+        if (streams.Length > 1 && IsRarFile(streams[1], ReaderOptions))
         {
             sourceStream.IsVolumes = true;
             streams[1].Position = 0;
@@ -63,7 +83,6 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
             ));
         }
 
-        //split mode or single file
         return new StreamRarArchiveVolume(sourceStream, ReaderOptions, i++).AsEnumerable();
     }
 
@@ -82,12 +101,12 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
                 volume.Stream.Position = 0;
                 return volume.Stream;
             });
-            return RarReader.Open(streams, ReaderOptions);
+            return (RarReader)RarReader.OpenReader(streams, ReaderOptions);
         }
 
         var stream = Volumes.First().Stream;
         stream.Position = 0;
-        return RarReader.Open(stream, ReaderOptions);
+        return (RarReader)RarReader.OpenReader(stream, ReaderOptions);
     }
 
     public override bool IsSolid => Volumes.First().IsSolidArchive;
@@ -96,187 +115,4 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
 
     public virtual int MinVersion => Volumes.First().MinVersion;
     public virtual int MaxVersion => Volumes.First().MaxVersion;
-
-    #region Creation
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="options"></param>
-    public static RarArchive Open(string filePath, ReaderOptions? options = null)
-    {
-        filePath.NotNullOrEmpty(nameof(filePath));
-        var fileInfo = new FileInfo(filePath);
-        return new RarArchive(
-            new SourceStream(
-                fileInfo,
-                i => RarArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                options ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="options"></param>
-    public static RarArchive Open(FileInfo fileInfo, ReaderOptions? options = null)
-    {
-        fileInfo.NotNull(nameof(fileInfo));
-        return new RarArchive(
-            new SourceStream(
-                fileInfo,
-                i => RarArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                options ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Takes a seekable Stream as a source
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="options"></param>
-    public static RarArchive Open(Stream stream, ReaderOptions? options = null)
-    {
-        stream.NotNull(nameof(stream));
-
-        if (stream is not { CanSeek: true })
-        {
-            throw new ArgumentException("Stream must be seekable", nameof(stream));
-        }
-
-        return new RarArchive(new SourceStream(stream, _ => null, options ?? new ReaderOptions()));
-    }
-
-    /// <summary>
-    /// Constructor with all file parts passed in
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    public static RarArchive Open(
-        IEnumerable<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        fileInfos.NotNull(nameof(fileInfos));
-        var files = fileInfos.ToArray();
-        return new RarArchive(
-            new SourceStream(
-                files[0],
-                i => i < files.Length ? files[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all stream parts passed in
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    public static RarArchive Open(IEnumerable<Stream> streams, ReaderOptions? readerOptions = null)
-    {
-        streams.NotNull(nameof(streams));
-        var strms = streams.ToArray();
-        return new RarArchive(
-            new SourceStream(
-                strms[0],
-                i => i < strms.Length ? strms[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Opens a RarArchive asynchronously from a stream.
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a RarArchive asynchronously from a FileInfo.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        FileInfo fileInfo,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfo, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a RarArchive asynchronously from multiple streams.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(streams, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a RarArchive asynchronously from multiple FileInfo objects.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfos, readerOptions));
-    }
-
-    public static bool IsRarFile(string filePath) => IsRarFile(new FileInfo(filePath));
-
-    public static bool IsRarFile(FileInfo fileInfo)
-    {
-        if (!fileInfo.Exists)
-        {
-            return false;
-        }
-        using Stream stream = fileInfo.OpenRead();
-        return IsRarFile(stream);
-    }
-
-    public static bool IsRarFile(Stream stream, ReaderOptions? options = null)
-    {
-        try
-        {
-            MarkHeader.Read(stream, true, false);
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    #endregion
 }

src/SharpCompress/Archives/Rar/SeekableFilePart.cs

@@ -1,6 +1,7 @@
 using System.IO;
 using SharpCompress.Common.Rar;
 using SharpCompress.Common.Rar.Headers;
+using SharpCompress.IO;
 
 namespace SharpCompress.Archives.Rar;
 
@@ -24,6 +25,76 @@ internal class SeekableFilePart : RarFilePart
 
     internal override Stream GetCompressedStream()
     {
+        Stream streamToUse;
+
+        // If the stream is a SourceStream in file mode with multi-threading enabled,
+        // create an independent stream to support concurrent extraction
+        if (
+            _stream is SourceStream sourceStream
+            && sourceStream.IsFileMode
+            && sourceStream.ReaderOptions.EnableMultiThreadedExtraction
+        )
+        {
+            var independentStream = sourceStream.CreateIndependentStream(0);
+            if (independentStream is not null)
+            {
+                streamToUse = independentStream;
+                streamToUse.Position = FileHeader.DataStartPosition;
+
+                if (FileHeader.R4Salt != null)
+                {
+                    var cryptKey = new CryptKey3(_password!);
+                    return new RarCryptoWrapper(streamToUse, FileHeader.R4Salt, cryptKey);
+                }
+
+                if (FileHeader.Rar5CryptoInfo != null)
+                {
+                    var cryptKey = new CryptKey5(_password!, FileHeader.Rar5CryptoInfo);
+                    return new RarCryptoWrapper(
+                        streamToUse,
+                        FileHeader.Rar5CryptoInfo.Salt,
+                        cryptKey
+                    );
+                }
+
+                return streamToUse;
+            }
+        }
+
+        // Check if the stream wraps a FileStream
+        Stream? underlyingStream = _stream;
+        if (_stream is IStreamStack streamStack)
+        {
+            underlyingStream = streamStack.BaseStream();
+        }
+
+        if (underlyingStream is FileStream fileStream)
+        {
+            // Create a new independent stream from the file
+            streamToUse = new FileStream(
+                fileStream.Name,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.Read
+            );
+            streamToUse.Position = FileHeader.DataStartPosition;
+
+            if (FileHeader.R4Salt != null)
+            {
+                var cryptKey = new CryptKey3(_password!);
+                return new RarCryptoWrapper(streamToUse, FileHeader.R4Salt, cryptKey);
+            }
+
+            if (FileHeader.Rar5CryptoInfo != null)
+            {
+                var cryptKey = new CryptKey5(_password!, FileHeader.Rar5CryptoInfo);
+                return new RarCryptoWrapper(streamToUse, FileHeader.Rar5CryptoInfo.Salt, cryptKey);
+            }
+
+            return streamToUse;
+        }
+
+        // Fall back to existing behavior for stream-based sources
         _stream.Position = FileHeader.DataStartPosition;
 
         if (FileHeader.R4Salt != null)

src/SharpCompress/Archives/SevenZip/SevenZipArchive.Factory.cs

@@ -0,0 +1,169 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Common.SevenZip;
+using SharpCompress.Compressors.LZMA.Utilites;
+using SharpCompress.IO;
+using SharpCompress.Readers;
+
+namespace SharpCompress.Archives.SevenZip;
+
+public partial class SevenZipArchive
+#if NET8_0_OR_GREATER
+    : IArchiveOpenable<IArchive, IAsyncArchive>,
+        IMultiArchiveOpenable<IArchive, IAsyncArchive>
+#endif
+{
+    public static IAsyncArchive OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        path.NotNullOrEmpty("path");
+        return (IAsyncArchive)OpenArchive(new FileInfo(path), readerOptions ?? new ReaderOptions());
+    }
+
+    public static IArchive OpenArchive(string filePath, ReaderOptions? readerOptions = null)
+    {
+        filePath.NotNullOrEmpty("filePath");
+        return OpenArchive(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
+    }
+
+    public static IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null)
+    {
+        fileInfo.NotNull("fileInfo");
+        return new SevenZipArchive(
+            new SourceStream(
+                fileInfo,
+                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfos.NotNull(nameof(fileInfos));
+        var files = fileInfos.ToArray();
+        return new SevenZipArchive(
+            new SourceStream(
+                files[0],
+                i => i < files.Length ? files[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IArchive OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        streams.NotNull(nameof(streams));
+        var strms = streams.ToArray();
+        return new SevenZipArchive(
+            new SourceStream(
+                strms[0],
+                i => i < strms.Length ? strms[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null)
+    {
+        stream.NotNull("stream");
+
+        if (stream is not { CanSeek: true })
+        {
+            throw new ArgumentException("Stream must be seekable", nameof(stream));
+        }
+
+        return new SevenZipArchive(
+            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
+        );
+    }
+
+    public static IAsyncArchive OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(stream, readerOptions);
+    }
+
+    public static IAsyncArchive OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
+
+    public static IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(streams, readerOptions);
+    }
+
+    public static IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
+
+    public static bool IsSevenZipFile(string filePath) => IsSevenZipFile(new FileInfo(filePath));
+
+    public static bool IsSevenZipFile(FileInfo fileInfo)
+    {
+        if (!fileInfo.Exists)
+        {
+            return false;
+        }
+        using Stream stream = fileInfo.OpenRead();
+        return IsSevenZipFile(stream);
+    }
+
+    public static bool IsSevenZipFile(Stream stream)
+    {
+        try
+        {
+            return SignatureMatch(stream);
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static ReadOnlySpan<byte> Signature =>
+        new byte[] { (byte)'7', (byte)'z', 0xBC, 0xAF, 0x27, 0x1C };
+
+    private static bool SignatureMatch(Stream stream)
+    {
+        var reader = new BinaryReader(stream);
+        ReadOnlySpan<byte> signatureBytes = reader.ReadBytes(6);
+        return signatureBytes.SequenceEqual(Signature);
+    }
+}

src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs

@@ -12,191 +12,22 @@ using SharpCompress.Readers;
 
 namespace SharpCompress.Archives.SevenZip;
 
-public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVolume>
+public partial class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVolume>
 {
     private ArchiveDatabase? _database;
 
-    /// <summary>
-    /// Constructor expects a filepath to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(string filePath, ReaderOptions? readerOptions = null)
-    {
-        filePath.NotNullOrEmpty("filePath");
-        return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
-    }
-
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
-    {
-        fileInfo.NotNull("fileInfo");
-        return new SevenZipArchive(
-            new SourceStream(
-                fileInfo,
-                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all file parts passed in
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(
-        IEnumerable<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        fileInfos.NotNull(nameof(fileInfos));
-        var files = fileInfos.ToArray();
-        return new SevenZipArchive(
-            new SourceStream(
-                files[0],
-                i => i < files.Length ? files[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all stream parts passed in
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(
-        IEnumerable<Stream> streams,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        streams.NotNull(nameof(streams));
-        var strms = streams.ToArray();
-        return new SevenZipArchive(
-            new SourceStream(
-                strms[0],
-                i => i < strms.Length ? strms[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Takes a seekable Stream as a source
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
-    {
-        stream.NotNull("stream");
-
-        if (stream is not { CanSeek: true })
-        {
-            throw new ArgumentException("Stream must be seekable", nameof(stream));
-        }
-
-        return new SevenZipArchive(
-            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
-        );
-    }
-
-    /// <summary>
-    /// Opens a SevenZipArchive asynchronously from a stream.
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a SevenZipArchive asynchronously from a FileInfo.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        FileInfo fileInfo,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfo, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a SevenZipArchive asynchronously from multiple streams.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(streams, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a SevenZipArchive asynchronously from multiple FileInfo objects.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfos, readerOptions));
-    }
-
-    /// <summary>
-    /// Constructor with a SourceStream able to handle FileInfo and Streams.
-    /// </summary>
-    /// <param name="sourceStream"></param>
     private SevenZipArchive(SourceStream sourceStream)
         : base(ArchiveType.SevenZip, sourceStream) { }
 
-    protected override IEnumerable<SevenZipVolume> LoadVolumes(SourceStream sourceStream)
-    {
-        sourceStream.NotNull("SourceStream is null").LoadAllParts(); //request all streams
-        return new SevenZipVolume(sourceStream, ReaderOptions, 0).AsEnumerable(); //simple single volume or split, multivolume not supported
-    }
-
-    public static bool IsSevenZipFile(string filePath) => IsSevenZipFile(new FileInfo(filePath));
-
-    public static bool IsSevenZipFile(FileInfo fileInfo)
-    {
-        if (!fileInfo.Exists)
-        {
-            return false;
-        }
-        using Stream stream = fileInfo.OpenRead();
-        return IsSevenZipFile(stream);
-    }
-
     internal SevenZipArchive()
         : base(ArchiveType.SevenZip) { }
 
+    protected override IEnumerable<SevenZipVolume> LoadVolumes(SourceStream sourceStream)
+    {
+        sourceStream.NotNull("SourceStream is null").LoadAllParts();
+        return new SevenZipVolume(sourceStream, ReaderOptions, 0).AsEnumerable();
+    }
+
     protected override IEnumerable<SevenZipArchiveEntry> LoadEntries(
         IEnumerable<SevenZipVolume> volumes
     )
@@ -222,7 +53,7 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
             foreach (var entry in group)
             {
                 entry.IsSolid = isSolid;
-                isSolid = true; //mark others in this group as solid - same as rar behaviour.
+                isSolid = true;
             }
         }
 
@@ -240,28 +71,6 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
         }
     }
 
-    public static bool IsSevenZipFile(Stream stream)
-    {
-        try
-        {
-            return SignatureMatch(stream);
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    private static ReadOnlySpan<byte> Signature =>
-        new byte[] { (byte)'7', (byte)'z', 0xBC, 0xAF, 0x27, 0x1C };
-
-    private static bool SignatureMatch(Stream stream)
-    {
-        var reader = new BinaryReader(stream);
-        ReadOnlySpan<byte> signatureBytes = reader.ReadBytes(6);
-        return signatureBytes.SequenceEqual(Signature);
-    }
-
     protected override IReader CreateReaderForSolidExtraction() =>
         new SevenZipReader(ReaderOptions, this);
 
@@ -298,9 +107,6 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
                 _currentEntry = dir;
                 yield return dir;
             }
-            // For non-directory entries, yield them without creating shared streams
-            // Each call to GetEntryStream() will create a fresh decompression stream
-            // to avoid state corruption issues with async operations
             foreach (var entry in entries.Where(x => !x.IsDirectory))
             {
                 _currentEntry = entry;
@@ -310,13 +116,6 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
 
         protected override EntryStream GetEntryStream()
         {
-            // Create a fresh decompression stream for each file (no state sharing).
-            // However, the LZMA decoder has bugs in its async implementation that cause
-            // state corruption even on fresh streams. The SyncOnlyStream wrapper
-            // works around these bugs by forcing async operations to use sync equivalents.
-            //
-            // TODO: Fix the LZMA decoder async bugs (in LzmaStream, Decoder, OutWindow)
-            // so this wrapper is no longer necessary.
             var entry = _currentEntry.NotNull("currentEntry is not null");
             if (entry.IsDirectory)
             {
@@ -326,15 +125,6 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
         }
     }
 
-    /// <summary>
-    /// WORKAROUND: Forces async operations to use synchronous equivalents.
-    /// This is necessary because the LZMA decoder has bugs in its async implementation
-    /// that cause state corruption (IndexOutOfRangeException, DataErrorException).
-    ///
-    /// The proper fix would be to repair the LZMA decoder's async methods
-    /// (LzmaStream.ReadAsync, Decoder.CodeAsync, OutWindow async operations),
-    /// but that requires deep changes to the decoder state machine.
-    /// </summary>
     private sealed class SyncOnlyStream : Stream
     {
         private readonly Stream _baseStream;
@@ -364,7 +154,6 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
         public override void Write(byte[] buffer, int offset, int count) =>
             _baseStream.Write(buffer, offset, count);
 
-        // Force async operations to use sync equivalents to avoid LZMA decoder bugs
         public override Task<int> ReadAsync(
             byte[] buffer,
             int offset,
@@ -395,7 +184,7 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
             return Task.CompletedTask;
         }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
         public override ValueTask<int> ReadAsync(
             Memory<byte> buffer,
             CancellationToken cancellationToken = default

src/SharpCompress/Archives/SevenZip/SevenZipArchiveEntry.cs

@@ -12,9 +12,8 @@ public class SevenZipArchiveEntry : SevenZipEntry, IArchiveEntry
 
     public Stream OpenEntryStream() => FilePart.GetCompressedStream();
 
-    public async ValueTask<Stream> OpenEntryStreamAsync(
-        CancellationToken cancellationToken = default
-    ) => OpenEntryStream();
+    public ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default) =>
+        new(OpenEntryStream());
 
     public IArchive Archive { get; }
 

src/SharpCompress/Archives/Tar/TarArchive.Factory.cs

@@ -0,0 +1,171 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Common.Tar;
+using SharpCompress.Common.Tar.Headers;
+using SharpCompress.IO;
+using SharpCompress.Readers;
+using SharpCompress.Writers;
+using SharpCompress.Writers.Tar;
+
+namespace SharpCompress.Archives.Tar;
+
+public partial class TarArchive
+#if NET8_0_OR_GREATER
+    : IWritableArchiveOpenable,
+        IMultiArchiveOpenable<IWritableArchive, IWritableAsyncArchive>
+#endif
+{
+    public static IWritableArchive OpenArchive(string filePath, ReaderOptions? readerOptions = null)
+    {
+        filePath.NotNullOrEmpty(nameof(filePath));
+        return OpenArchive(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
+    }
+
+    public static IWritableArchive OpenArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfo.NotNull(nameof(fileInfo));
+        return new TarArchive(
+            new SourceStream(
+                fileInfo,
+                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfos.NotNull(nameof(fileInfos));
+        var files = fileInfos.ToArray();
+        return new TarArchive(
+            new SourceStream(
+                files[0],
+                i => i < files.Length ? files[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        streams.NotNull(nameof(streams));
+        var strms = streams.ToArray();
+        return new TarArchive(
+            new SourceStream(
+                strms[0],
+                i => i < strms.Length ? strms[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null)
+    {
+        stream.NotNull(nameof(stream));
+
+        if (stream is not { CanSeek: true })
+        {
+            throw new ArgumentException("Stream must be seekable", nameof(stream));
+        }
+
+        return new TarArchive(
+            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
+        );
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(stream, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(new FileInfo(path), readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(streams, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
+
+    public static bool IsTarFile(string filePath) => IsTarFile(new FileInfo(filePath));
+
+    public static bool IsTarFile(FileInfo fileInfo)
+    {
+        if (!fileInfo.Exists)
+        {
+            return false;
+        }
+        using Stream stream = fileInfo.OpenRead();
+        return IsTarFile(stream);
+    }
+
+    public static bool IsTarFile(Stream stream)
+    {
+        try
+        {
+            var tarHeader = new TarHeader(new ArchiveEncoding());
+            var readSucceeded = tarHeader.Read(new BinaryReader(stream));
+            var isEmptyArchive =
+                tarHeader.Name?.Length == 0
+                && tarHeader.Size == 0
+                && Enum.IsDefined(typeof(EntryType), tarHeader.EntryType);
+            return readSucceeded || isEmptyArchive;
+        }
+        catch { }
+        return false;
+    }
+
+    public static IWritableArchive CreateArchive() => new TarArchive();
+
+    public static IWritableAsyncArchive CreateAsyncArchive() => new TarArchive();
+}

src/SharpCompress/Archives/Tar/TarArchive.cs

@@ -15,196 +15,14 @@ using SharpCompress.Writers.Tar;
 
 namespace SharpCompress.Archives.Tar;
 
-public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
+public partial class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
 {
-    /// <summary>
-    /// Constructor expects a filepath to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="readerOptions"></param>
-    public static TarArchive Open(string filePath, ReaderOptions? readerOptions = null)
-    {
-        filePath.NotNullOrEmpty(nameof(filePath));
-        return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
-    }
-
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    public static TarArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
-    {
-        fileInfo.NotNull(nameof(fileInfo));
-        return new TarArchive(
-            new SourceStream(
-                fileInfo,
-                i => ArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all file parts passed in
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    public static TarArchive Open(
-        IEnumerable<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        fileInfos.NotNull(nameof(fileInfos));
-        var files = fileInfos.ToArray();
-        return new TarArchive(
-            new SourceStream(
-                files[0],
-                i => i < files.Length ? files[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all stream parts passed in
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    public static TarArchive Open(IEnumerable<Stream> streams, ReaderOptions? readerOptions = null)
-    {
-        streams.NotNull(nameof(streams));
-        var strms = streams.ToArray();
-        return new TarArchive(
-            new SourceStream(
-                strms[0],
-                i => i < strms.Length ? strms[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Takes a seekable Stream as a source
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    public static TarArchive Open(Stream stream, ReaderOptions? readerOptions = null)
-    {
-        stream.NotNull(nameof(stream));
-
-        if (stream is not { CanSeek: true })
-        {
-            throw new ArgumentException("Stream must be seekable", nameof(stream));
-        }
-
-        return new TarArchive(
-            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
-        );
-    }
-
-    /// <summary>
-    /// Opens a TarArchive asynchronously from a stream.
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a TarArchive asynchronously from a FileInfo.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        FileInfo fileInfo,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfo, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a TarArchive asynchronously from multiple streams.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(streams, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a TarArchive asynchronously from multiple FileInfo objects.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfos, readerOptions));
-    }
-
-    public static bool IsTarFile(string filePath) => IsTarFile(new FileInfo(filePath));
-
-    public static bool IsTarFile(FileInfo fileInfo)
-    {
-        if (!fileInfo.Exists)
-        {
-            return false;
-        }
-        using Stream stream = fileInfo.OpenRead();
-        return IsTarFile(stream);
-    }
-
-    public static bool IsTarFile(Stream stream)
-    {
-        try
-        {
-            var tarHeader = new TarHeader(new ArchiveEncoding());
-            var readSucceeded = tarHeader.Read(new BinaryReader(stream));
-            var isEmptyArchive =
-                tarHeader.Name?.Length == 0
-                && tarHeader.Size == 0
-                && Enum.IsDefined(typeof(EntryType), tarHeader.EntryType);
-            return readSucceeded || isEmptyArchive;
-        }
-        catch { }
-        return false;
-    }
-
     protected override IEnumerable<TarVolume> LoadVolumes(SourceStream sourceStream)
     {
-        sourceStream.NotNull("SourceStream is null").LoadAllParts(); //request all streams
-        return new TarVolume(sourceStream, ReaderOptions, 1).AsEnumerable(); //simple single volume or split, multivolume not supported
+        sourceStream.NotNull("SourceStream is null").LoadAllParts();
+        return new TarVolume(sourceStream, ReaderOptions, 1).AsEnumerable();
     }
 
-    /// <summary>
-    /// Constructor with a SourceStream able to handle FileInfo and Streams.
-    /// </summary>
-    /// <param name="sourceStream"></param>
     private TarArchive(SourceStream sourceStream)
         : base(ArchiveType.Tar, sourceStream) { }
 
@@ -269,8 +87,6 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
         }
     }
 
-    public static TarArchive Create() => new();
-
     protected override TarArchiveEntry CreateEntryInternal(
         string filePath,
         Stream source,
@@ -364,13 +180,13 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
     {
         var stream = Volumes.Single().Stream;
         stream.Position = 0;
-        return TarReader.Open(stream);
+        return TarReader.OpenReader(stream);
     }
 
     protected override ValueTask<IAsyncReader> CreateReaderForSolidExtractionAsync()
     {
         var stream = Volumes.Single().Stream;
         stream.Position = 0;
-        return new(TarReader.Open(stream));
+        return new((IAsyncReader)TarReader.OpenReader(stream));
     }
 }

src/SharpCompress/Archives/Tar/TarArchiveEntry.cs

@@ -14,9 +14,8 @@ public class TarArchiveEntry : TarEntry, IArchiveEntry
 
     public virtual Stream OpenEntryStream() => Parts.Single().GetCompressedStream().NotNull();
 
-    public async ValueTask<Stream> OpenEntryStreamAsync(
-        CancellationToken cancellationToken = default
-    ) => OpenEntryStream();
+    public ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default) =>
+        new(OpenEntryStream());
 
     #region IArchiveEntry Members
 

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

@@ -0,0 +1,324 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Common.Zip;
+using SharpCompress.Common.Zip.Headers;
+using SharpCompress.IO;
+using SharpCompress.Readers;
+
+namespace SharpCompress.Archives.Zip;
+
+public partial class ZipArchive
+#if NET8_0_OR_GREATER
+    : IWritableArchiveOpenable,
+        IMultiArchiveOpenable<IWritableArchive, IWritableAsyncArchive>
+#endif
+{
+    public static IWritableArchive OpenArchive(string filePath, ReaderOptions? readerOptions = null)
+    {
+        filePath.NotNullOrEmpty(nameof(filePath));
+        return OpenArchive(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
+    }
+
+    public static IWritableArchive OpenArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfo.NotNull(nameof(fileInfo));
+        return new ZipArchive(
+            new SourceStream(
+                fileInfo,
+                i => ZipArchiveVolumeFactory.GetFilePart(i, fileInfo),
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        fileInfos.NotNull(nameof(fileInfos));
+        var files = fileInfos.ToArray();
+        return new ZipArchive(
+            new SourceStream(
+                files[0],
+                i => i < files.Length ? files[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(
+        IEnumerable<Stream> streams,
+        ReaderOptions? readerOptions = null
+    )
+    {
+        streams.NotNull(nameof(streams));
+        var strms = streams.ToArray();
+        return new ZipArchive(
+            new SourceStream(
+                strms[0],
+                i => i < strms.Length ? strms[i] : null,
+                readerOptions ?? new ReaderOptions()
+            )
+        );
+    }
+
+    public static IWritableArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null)
+    {
+        stream.NotNull(nameof(stream));
+
+        if (stream is not { CanSeek: true })
+        {
+            throw new ArgumentException("Stream must be seekable", nameof(stream));
+        }
+
+        return new ZipArchive(
+            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
+        );
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        string path,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(path, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        Stream stream,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(stream, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        FileInfo fileInfo,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(streams, readerOptions);
+    }
+
+    public static IWritableAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IWritableAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
+
+    public static bool IsZipFile(
+        string filePath,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize
+    ) => IsZipFile(new FileInfo(filePath), password, bufferSize);
+
+    public static bool IsZipFile(
+        FileInfo fileInfo,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize
+    )
+    {
+        if (!fileInfo.Exists)
+        {
+            return false;
+        }
+        using Stream stream = fileInfo.OpenRead();
+        return IsZipFile(stream, password, bufferSize);
+    }
+
+    public static bool IsZipFile(
+        Stream stream,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize
+    )
+    {
+        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
+        try
+        {
+            if (stream is not SharpCompressStream)
+            {
+                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
+            }
+
+            var header = headerFactory
+                .ReadStreamHeader(stream)
+                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
+            if (header is null)
+            {
+                return false;
+            }
+            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
+        }
+        catch (CryptographicException)
+        {
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public static bool IsZipMulti(
+        Stream stream,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize
+    )
+    {
+        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
+        try
+        {
+            if (stream is not SharpCompressStream)
+            {
+                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
+            }
+
+            var header = headerFactory
+                .ReadStreamHeader(stream)
+                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
+            if (header is null)
+            {
+                if (stream.CanSeek)
+                {
+                    var z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
+                    var x = z.ReadSeekableHeader(stream, useSync: true).FirstOrDefault();
+                    return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
+                }
+                else
+                {
+                    return false;
+                }
+            }
+            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
+        }
+        catch (CryptographicException)
+        {
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public static async ValueTask<bool> IsZipFileAsync(
+        Stream stream,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
+        try
+        {
+            if (stream is not SharpCompressStream)
+            {
+                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
+            }
+
+            var header = await headerFactory
+                .ReadStreamHeaderAsync(stream)
+                .Where(x => x.ZipHeaderType != ZipHeaderType.Split)
+                .FirstOrDefaultAsync(cancellationToken);
+            if (header is null)
+            {
+                return false;
+            }
+            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
+        }
+        catch (CryptographicException)
+        {
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    public static IWritableArchive CreateArchive() => new ZipArchive();
+
+    public static IWritableAsyncArchive CreateAsyncArchive() => new ZipArchive();
+
+    public static async ValueTask<bool> IsZipMultiAsync(
+        Stream stream,
+        string? password = null,
+        int bufferSize = ReaderOptions.DefaultBufferSize,
+        CancellationToken cancellationToken = default
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
+        try
+        {
+            if (stream is not SharpCompressStream)
+            {
+                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
+            }
+
+            var header = headerFactory
+                .ReadStreamHeader(stream)
+                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
+            if (header is null)
+            {
+                if (stream.CanSeek)
+                {
+                    var z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
+                    ZipHeader? x = null;
+                    await foreach (
+                        var h in z.ReadSeekableHeaderAsync(stream)
+                            .WithCancellation(cancellationToken)
+                    )
+                    {
+                        x = h;
+                        break;
+                    }
+                    return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
+                }
+                else
+                {
+                    return false;
+                }
+            }
+            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
+        }
+        catch (CryptographicException)
+        {
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+}

src/SharpCompress/Archives/Zip/ZipArchive.cs

@@ -16,21 +16,12 @@ using SharpCompress.Writers.Zip;
 
 namespace SharpCompress.Archives.Zip;
 
-public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
+public partial class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
 {
     private readonly SeekableZipHeaderFactory? headerFactory;
 
-    /// <summary>
-    /// Gets or sets the compression level applied to files added to the archive,
-    /// if the compression method is set to deflate
-    /// </summary>
     public CompressionLevel DeflateCompressionLevel { get; set; }
 
-    /// <summary>
-    /// Constructor with a SourceStream able to handle FileInfo and Streams.
-    /// </summary>
-    /// <param name="sourceStream"></param>
-    /// <param name="options"></param>
     internal ZipArchive(SourceStream sourceStream)
         : base(ArchiveType.Zip, sourceStream) =>
         headerFactory = new SeekableZipHeaderFactory(
@@ -38,371 +29,36 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
             sourceStream.ReaderOptions.ArchiveEncoding
         );
 
-    /// <summary>
-    /// Constructor expects a filepath to an existing file.
-    /// </summary>
-    /// <param name="filePath"></param>
-    /// <param name="readerOptions"></param>
-    public static ZipArchive Open(string filePath, ReaderOptions? readerOptions = null)
-    {
-        filePath.NotNullOrEmpty(nameof(filePath));
-        return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
-    }
-
-    /// <summary>
-    /// Constructor with a FileInfo object to an existing file.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    public static ZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
-    {
-        fileInfo.NotNull(nameof(fileInfo));
-        return new ZipArchive(
-            new SourceStream(
-                fileInfo,
-                i => ZipArchiveVolumeFactory.GetFilePart(i, fileInfo),
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all file parts passed in
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    public static ZipArchive Open(
-        IEnumerable<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null
-    )
-    {
-        fileInfos.NotNull(nameof(fileInfos));
-        var files = fileInfos.ToArray();
-        return new ZipArchive(
-            new SourceStream(
-                files[0],
-                i => i < files.Length ? files[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Constructor with all stream parts passed in
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    public static ZipArchive Open(IEnumerable<Stream> streams, ReaderOptions? readerOptions = null)
-    {
-        streams.NotNull(nameof(streams));
-        var strms = streams.ToArray();
-        return new ZipArchive(
-            new SourceStream(
-                strms[0],
-                i => i < strms.Length ? strms[i] : null,
-                readerOptions ?? new ReaderOptions()
-            )
-        );
-    }
-
-    /// <summary>
-    /// Takes a seekable Stream as a source
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    public static ZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
-    {
-        stream.NotNull(nameof(stream));
-
-        if (stream is not { CanSeek: true })
-        {
-            throw new ArgumentException("Stream must be seekable", nameof(stream));
-        }
-
-        return new ZipArchive(
-            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
-        );
-    }
-
-    /// <summary>
-    /// Opens a ZipArchive asynchronously from a stream.
-    /// </summary>
-    /// <param name="stream"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a ZipArchive asynchronously from a FileInfo.
-    /// </summary>
-    /// <param name="fileInfo"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        FileInfo fileInfo,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfo, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a ZipArchive asynchronously from multiple streams.
-    /// </summary>
-    /// <param name="streams"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(streams, readerOptions));
-    }
-
-    /// <summary>
-    /// Opens a ZipArchive asynchronously from multiple FileInfo objects.
-    /// </summary>
-    /// <param name="fileInfos"></param>
-    /// <param name="readerOptions"></param>
-    /// <param name="cancellationToken"></param>
-    public static ValueTask<IAsyncArchive> OpenAsync(
-        IReadOnlyList<FileInfo> fileInfos,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(fileInfos, readerOptions));
-    }
-
-    public static bool IsZipFile(
-        string filePath,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize
-    ) => IsZipFile(new FileInfo(filePath), password, bufferSize);
-
-    public static bool IsZipFile(
-        FileInfo fileInfo,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize
-    )
-    {
-        if (!fileInfo.Exists)
-        {
-            return false;
-        }
-        using Stream stream = fileInfo.OpenRead();
-        return IsZipFile(stream, password, bufferSize);
-    }
-
-    public static bool IsZipFile(
-        Stream stream,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize
-    )
-    {
-        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
-        try
-        {
-            if (stream is not SharpCompressStream)
-            {
-                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
-            }
-
-            var header = headerFactory
-                .ReadStreamHeader(stream)
-                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
-            if (header is null)
-            {
-                return false;
-            }
-            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
-        }
-        catch (CryptographicException)
-        {
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    public static bool IsZipMulti(
-        Stream stream,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize
-    )
-    {
-        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
-        try
-        {
-            if (stream is not SharpCompressStream)
-            {
-                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
-            }
-
-            var header = headerFactory
-                .ReadStreamHeader(stream)
-                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
-            if (header is null)
-            {
-                if (stream.CanSeek) //could be multipart. Test for central directory - might not be z64 safe
-                {
-                    var z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
-                    var x = z.ReadSeekableHeader(stream, useSync: true).FirstOrDefault();
-                    return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
-                }
-                else
-                {
-                    return false;
-                }
-            }
-            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
-        }
-        catch (CryptographicException)
-        {
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    public static async ValueTask<bool> IsZipFileAsync(
-        Stream stream,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
-        try
-        {
-            if (stream is not SharpCompressStream)
-            {
-                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
-            }
-
-            var header = await headerFactory
-                .ReadStreamHeaderAsync(stream)
-                .Where(x => x.ZipHeaderType != ZipHeaderType.Split)
-                .FirstOrDefaultAsync();
-            if (header is null)
-            {
-                return false;
-            }
-            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
-        }
-        catch (CryptographicException)
-        {
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    public static async ValueTask<bool> IsZipMultiAsync(
-        Stream stream,
-        string? password = null,
-        int bufferSize = ReaderOptions.DefaultBufferSize,
-        CancellationToken cancellationToken = default
-    )
-    {
-        cancellationToken.ThrowIfCancellationRequested();
-        var headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding(), null);
-        try
-        {
-            if (stream is not SharpCompressStream)
-            {
-                stream = new SharpCompressStream(stream, bufferSize: bufferSize);
-            }
-
-            var header = headerFactory
-                .ReadStreamHeader(stream)
-                .FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
-            if (header is null)
-            {
-                if (stream.CanSeek) //could be multipart. Test for central directory - might not be z64 safe
-                {
-                    var z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
-                    ZipHeader? x = null;
-                    await foreach (
-                        var h in z.ReadSeekableHeaderAsync(stream)
-                            .WithCancellation(cancellationToken)
-                    )
-                    {
-                        x = h;
-                        break;
-                    }
-                    return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
-                }
-                else
-                {
-                    return false;
-                }
-            }
-            return Enum.IsDefined(typeof(ZipHeaderType), header.ZipHeaderType);
-        }
-        catch (CryptographicException)
-        {
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
+    internal ZipArchive()
+        : base(ArchiveType.Zip) { }
 
     protected override IEnumerable<ZipVolume> LoadVolumes(SourceStream stream)
     {
-        stream.LoadAllParts(); //request all streams
+        stream.LoadAllParts();
         stream.Position = 0;
 
         var streams = stream.Streams.ToList();
         var idx = 0;
-        if (streams.Count() > 1) //test part 2 - true = multipart not split
+        if (streams.Count() > 1)
         {
-            streams[1].Position += 4; //skip the POST_DATA_DESCRIPTOR to prevent an exception
+            streams[1].Position += 4;
             var isZip = IsZipFile(streams[1], ReaderOptions.Password, ReaderOptions.BufferSize);
             streams[1].Position -= 4;
             if (isZip)
             {
                 stream.IsVolumes = true;
 
-                var tmp = streams[0]; //arcs as zip, z01 ... swap the zip the end
+                var tmp = streams[0];
                 streams.RemoveAt(0);
                 streams.Add(tmp);
 
-                //streams[0].Position = 4; //skip the POST_DATA_DESCRIPTOR to prevent an exception
                 return streams.Select(a => new ZipVolume(a, ReaderOptions, idx++));
             }
         }
 
-        //split mode or single file
         return new ZipVolume(stream, ReaderOptions, idx++).AsEnumerable();
     }
 
-    internal ZipArchive()
-        : base(ArchiveType.Zip) { }
-
     protected override IEnumerable<ZipArchiveEntry> LoadEntries(IEnumerable<ZipVolume> volumes)
     {
         var vols = volumes.ToArray();
@@ -584,19 +240,17 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
         DateTime? modified
     ) => new ZipWritableArchiveEntry(this, directoryPath, modified);
 
-    public static ZipArchive Create() => new();
-
     protected override IReader CreateReaderForSolidExtraction()
     {
         var stream = Volumes.Single().Stream;
         ((IStreamStack)stream).StackSeek(0);
-        return ZipReader.Open(stream, ReaderOptions, Entries);
+        return ZipReader.OpenReader(stream, ReaderOptions, Entries);
     }
 
     protected override ValueTask<IAsyncReader> CreateReaderForSolidExtractionAsync()
     {
         var stream = Volumes.Single().Stream;
         stream.Position = 0;
-        return new(ZipReader.Open(stream));
+        return new((IAsyncReader)ZipReader.OpenReader(stream));
     }
 }

src/SharpCompress/Common/AsyncBinaryReader.cs

@@ -51,11 +51,19 @@ namespace SharpCompress.Common
             return BinaryPrimitives.ReadUInt64LittleEndian(_buffer);
         }
 
-        public async ValueTask<byte[]> ReadBytesAsync(int count, CancellationToken ct = default)
+        public async ValueTask ReadBytesAsync(
+            byte[] bytes,
+            int offset,
+            int count,
+            CancellationToken ct = default
+        )
         {
-            var result = new byte[count];
-            await _stream.ReadExactAsync(result, 0, count, ct).ConfigureAwait(false);
-            return result;
+            await _stream.ReadExactAsync(bytes, offset, count, ct).ConfigureAwait(false);
+        }
+
+        public async ValueTask SkipAsync(int count, CancellationToken ct = default)
+        {
+            await _stream.SkipAsync(count, ct).ConfigureAwait(false);
         }
 
         public void Dispose()
@@ -74,7 +82,7 @@ namespace SharpCompress.Common
             }
         }
 
-#if NET6_0_OR_GREATER
+#if NET8_0_OR_GREATER
         public async ValueTask DisposeAsync()
         {
             if (_disposed)

src/SharpCompress/Common/EntryStream.cs

@@ -93,7 +93,7 @@ public class EntryStream : Stream, IStreamStack
         _stream.Dispose();
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
     {
         if (_isDisposed)
@@ -171,7 +171,7 @@ public class EntryStream : Stream, IStreamStack
         return read;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Common/GZip/GZipEntry.cs

@@ -40,6 +40,6 @@ public class GZipEntry : Entry
 
     internal static IEnumerable<GZipEntry> GetEntries(Stream stream, OptionsBase options)
     {
-        yield return new GZipEntry(new GZipFilePart(stream, options.ArchiveEncoding));
+        yield return new GZipEntry(GZipFilePart.Create(stream, options.ArchiveEncoding));
     }
 }

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -2,6 +2,8 @@ using System;
 using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.Deflate;
@@ -13,28 +15,58 @@ internal sealed class GZipFilePart : FilePart
     private string? _name;
     private readonly Stream _stream;
 
-    internal GZipFilePart(Stream stream, IArchiveEncoding archiveEncoding)
-        : base(archiveEncoding)
+    internal static GZipFilePart Create(Stream stream, IArchiveEncoding archiveEncoding)
     {
-        _stream = stream;
-        ReadAndValidateGzipHeader();
+        var part = new GZipFilePart(stream, archiveEncoding);
+
+        part.ReadAndValidateGzipHeader();
         if (stream.CanSeek)
         {
             var position = stream.Position;
             stream.Position = stream.Length - 8;
-            ReadTrailer();
+            part.ReadTrailer();
             stream.Position = position;
-            EntryStartPosition = 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.
-            EntryStartPosition = 0;
+            part.EntryStartPosition = 0;
         }
+        return part;
     }
 
-    internal long EntryStartPosition { get; }
+    internal static async ValueTask<GZipFilePart> CreateAsync(
+        Stream stream,
+        IArchiveEncoding archiveEncoding,
+        CancellationToken cancellationToken = default
+    )
+    {
+        var part = new GZipFilePart(stream, archiveEncoding);
+
+        await part.ReadAndValidateGzipHeaderAsync(cancellationToken);
+        if (stream.CanSeek)
+        {
+            var position = stream.Position;
+            stream.Position = stream.Length - 8;
+            await part.ReadTrailerAsync(cancellationToken);
+            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 GZipFilePart(Stream stream, IArchiveEncoding archiveEncoding)
+        : base(archiveEncoding) => _stream = stream;
+
+    internal long EntryStartPosition { get; private set; }
 
     internal DateTime? DateModified { get; private set; }
     internal uint? Crc { get; private set; }
@@ -51,12 +83,22 @@ internal sealed class GZipFilePart : FilePart
     {
         // Read and potentially verify the GZIP trailer: CRC32 and  size mod 2^32
         Span<byte> trailer = stackalloc byte[8];
-        var n = _stream.Read(trailer);
+        _stream.ReadFully(trailer);
 
         Crc = BinaryPrimitives.ReadUInt32LittleEndian(trailer);
         UncompressedSize = BinaryPrimitives.ReadUInt32LittleEndian(trailer.Slice(4));
     }
 
+    private async ValueTask ReadTrailerAsync(CancellationToken cancellationToken = default)
+    {
+        // Read and potentially verify the GZIP trailer: CRC32 and  size mod 2^32
+        var trailer = new byte[8];
+        _ = await _stream.ReadFullyAsync(trailer, 0, 8, cancellationToken);
+
+        Crc = BinaryPrimitives.ReadUInt32LittleEndian(trailer);
+        UncompressedSize = BinaryPrimitives.ReadUInt32LittleEndian(trailer.AsSpan().Slice(4));
+    }
+
     private void ReadAndValidateGzipHeader()
     {
         // read the header on the first read
@@ -109,6 +151,61 @@ internal sealed class GZipFilePart : FilePart
         }
     }
 
+    private async ValueTask ReadAndValidateGzipHeaderAsync(
+        CancellationToken cancellationToken = default
+    )
+    {
+        // read the header on the first read
+        var header = new byte[10];
+        var n = await _stream.ReadAsync(header, 0, 10, cancellationToken);
+
+        // workitem 8501: handle edge case (decompress empty stream)
+        if (n == 0)
+        {
+            return;
+        }
+
+        if (n != 10)
+        {
+            throw new ZlibException("Not a valid GZIP stream.");
+        }
+
+        if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
+        {
+            throw new ZlibException("Bad GZIP header.");
+        }
+
+        var timet = BinaryPrimitives.ReadInt32LittleEndian(header.AsSpan().Slice(4));
+        DateModified = TarHeader.EPOCH.AddSeconds(timet);
+        if ((header[3] & 0x04) == 0x04)
+        {
+            // read and discard extra field
+            var lengthField = new byte[2];
+            _ = await _stream.ReadAsync(lengthField, 0, 2, cancellationToken);
+
+            var extraLength = (short)(lengthField[0] + (lengthField[1] * 256));
+            var extra = new byte[extraLength];
+
+            if (!await _stream.ReadFullyAsync(extra, cancellationToken))
+            {
+                throw new ZlibException("Unexpected end-of-file reading GZIP header.");
+            }
+        }
+        if ((header[3] & 0x08) == 0x08)
+        {
+            _name = await ReadZeroTerminatedStringAsync(_stream, cancellationToken);
+        }
+        if ((header[3] & 0x10) == 0x010)
+        {
+            await ReadZeroTerminatedStringAsync(_stream, cancellationToken);
+        }
+        if ((header[3] & 0x02) == 0x02)
+        {
+            var buf = new byte[1];
+            _ = await _stream.ReadAsync(buf, 0, 1, cancellationToken); // CRC16, ignore
+        }
+    }
+
     private string ReadZeroTerminatedString(Stream stream)
     {
         Span<byte> buf1 = stackalloc byte[1];
@@ -134,4 +231,33 @@ internal sealed class GZipFilePart : FilePart
         var buffer = list.ToArray();
         return ArchiveEncoding.Decode(buffer);
     }
+
+    private async ValueTask<string> ReadZeroTerminatedStringAsync(
+        Stream stream,
+        CancellationToken cancellationToken = default
+    )
+    {
+        var buf1 = new byte[1];
+        var list = new List<byte>();
+        var done = false;
+        do
+        {
+            // workitem 7740
+            var n = await stream.ReadAsync(buf1, 0, 1, cancellationToken);
+            if (n != 1)
+            {
+                throw new ZlibException("Unexpected EOF reading GZIP header.");
+            }
+            if (buf1[0] == 0)
+            {
+                done = true;
+            }
+            else
+            {
+                list.Add(buf1[0]);
+            }
+        } while (!done);
+        var buffer = list.ToArray();
+        return ArchiveEncoding.Decode(buffer);
+    }
 }

src/SharpCompress/Common/Tar/TarFilePart.cs

@@ -1,5 +1,6 @@
 using System.IO;
 using SharpCompress.Common.Tar.Headers;
+using SharpCompress.IO;
 
 namespace SharpCompress.Common.Tar;
 
@@ -20,8 +21,45 @@ internal sealed class TarFilePart : FilePart
 
     internal override Stream GetCompressedStream()
     {
-        if (_seekableStream != null)
+        if (_seekableStream is not null)
         {
+            // If the seekable stream is a SourceStream in file mode with multi-threading enabled,
+            // create an independent stream to support concurrent extraction
+            if (
+                _seekableStream is SourceStream sourceStream
+                && sourceStream.IsFileMode
+                && sourceStream.ReaderOptions.EnableMultiThreadedExtraction
+            )
+            {
+                var independentStream = sourceStream.CreateIndependentStream(0);
+                if (independentStream is not null)
+                {
+                    independentStream.Position = Header.DataStartPosition ?? 0;
+                    return new TarReadOnlySubStream(independentStream, Header.Size);
+                }
+            }
+
+            // Check if the seekable stream wraps a FileStream
+            Stream? underlyingStream = _seekableStream;
+            if (_seekableStream is IStreamStack streamStack)
+            {
+                underlyingStream = streamStack.BaseStream();
+            }
+
+            if (underlyingStream is FileStream fileStream)
+            {
+                // Create a new independent stream from the file
+                var independentStream = new FileStream(
+                    fileStream.Name,
+                    FileMode.Open,
+                    FileAccess.Read,
+                    FileShare.Read
+                );
+                independentStream.Position = Header.DataStartPosition ?? 0;
+                return new TarReadOnlySubStream(independentStream, Header.Size);
+            }
+
+            // Fall back to existing behavior for stream-based sources
             _seekableStream.Position = Header.DataStartPosition ?? 0;
             return new TarReadOnlySubStream(_seekableStream, Header.Size);
         }

src/SharpCompress/Common/Tar/TarReadOnlySubStream.cs

@@ -66,7 +66,7 @@ internal class TarReadOnlySubStream : SharpCompressStream, IStreamStack
         base.Dispose(disposing);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask DisposeAsync()
     {
         if (_isDisposed)
@@ -170,7 +170,7 @@ internal class TarReadOnlySubStream : SharpCompressStream, IStreamStack
         return read;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask<int> ReadAsync(
         System.Memory<byte> buffer,
         System.Threading.CancellationToken cancellationToken = default

src/SharpCompress/Common/Zip/Headers/DirectoryEndHeader.cs

@@ -29,7 +29,8 @@ internal class DirectoryEndHeader : ZipHeader
         DirectorySize = await reader.ReadUInt32Async();
         DirectoryStartOffsetRelativeToDisk = await reader.ReadUInt32Async();
         CommentLength = await reader.ReadUInt16Async();
-        Comment = await reader.ReadBytesAsync(CommentLength);
+        Comment = new byte[CommentLength];
+        await reader.ReadBytesAsync(Comment, 0, CommentLength);
     }
 
     public ushort VolumeNumber { get; private set; }

src/SharpCompress/Common/Zip/Headers/DirectoryEntryHeader.cs

@@ -53,10 +53,12 @@ internal class DirectoryEntryHeader : ZipFileEntry
         InternalFileAttributes = await reader.ReadUInt16Async();
         ExternalFileAttributes = await reader.ReadUInt32Async();
         RelativeOffsetOfEntryHeader = await reader.ReadUInt32Async();
-
-        var name = await reader.ReadBytesAsync(nameLength);
-        var extra = await reader.ReadBytesAsync(extraLength);
-        var comment = await reader.ReadBytesAsync(commentLength);
+        var name = new byte[nameLength];
+        var extra = new byte[extraLength];
+        var comment = new byte[commentLength];
+        await reader.ReadBytesAsync(name, 0, nameLength);
+        await reader.ReadBytesAsync(extra, 0, extraLength);
+        await reader.ReadBytesAsync(comment, 0, commentLength);
 
         ProcessReadData(name, extra, comment);
     }

src/SharpCompress/Common/Zip/Headers/LocalEntryHeader.cs

@@ -37,8 +37,10 @@ internal class LocalEntryHeader(IArchiveEncoding archiveEncoding)
         UncompressedSize = await reader.ReadUInt32Async();
         var nameLength = await reader.ReadUInt16Async();
         var extraLength = await reader.ReadUInt16Async();
-        var name = await reader.ReadBytesAsync(nameLength);
-        var extra = await reader.ReadBytesAsync(extraLength);
+        var name = new byte[nameLength];
+        var extra = new byte[extraLength];
+        await reader.ReadBytesAsync(name, 0, nameLength);
+        await reader.ReadBytesAsync(extra, 0, extraLength);
 
         ProcessReadData(name, extra);
     }

src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndHeader.cs

@@ -38,12 +38,11 @@ internal class Zip64DirectoryEndHeader : ZipHeader
         TotalNumberOfEntries = (long)await reader.ReadUInt64Async();
         DirectorySize = (long)await reader.ReadUInt64Async();
         DirectoryStartOffsetRelativeToDisk = (long)await reader.ReadUInt64Async();
-        DataSector = await reader.ReadBytesAsync(
-            (int)(
-                SizeOfDirectoryEndRecord
-                - SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS
-            )
+        var size = (int)(
+            SizeOfDirectoryEndRecord - SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS
         );
+        DataSector = new byte[size];
+        await reader.ReadBytesAsync(DataSector, 0, size);
     }
 
     private const int SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS = 44;

src/SharpCompress/Common/Zip/SeekableZipFilePart.cs

@@ -2,13 +2,16 @@ using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
+using SharpCompress.IO;
 
 namespace SharpCompress.Common.Zip;
 
 internal class SeekableZipFilePart : ZipFilePart
 {
-    private bool _isLocalHeaderLoaded;
+    private volatile bool _isLocalHeaderLoaded;
     private readonly SeekableZipHeaderFactory _headerFactory;
+    private readonly object _headerLock = new();
+    private readonly SemaphoreSlim _asyncHeaderSemaphore = new(1, 1);
 
     internal SeekableZipFilePart(
         SeekableZipHeaderFactory headerFactory,
@@ -21,8 +24,14 @@ internal class SeekableZipFilePart : ZipFilePart
     {
         if (!_isLocalHeaderLoaded)
         {
-            LoadLocalHeader();
-            _isLocalHeaderLoaded = true;
+            lock (_headerLock)
+            {
+                if (!_isLocalHeaderLoaded)
+                {
+                    LoadLocalHeader();
+                    _isLocalHeaderLoaded = true;
+                }
+            }
         }
         return base.GetCompressedStream();
     }
@@ -33,22 +42,173 @@ internal class SeekableZipFilePart : ZipFilePart
     {
         if (!_isLocalHeaderLoaded)
         {
-            await LoadLocalHeaderAsync(cancellationToken);
-            _isLocalHeaderLoaded = true;
+            await _asyncHeaderSemaphore.WaitAsync(cancellationToken);
+            try
+            {
+                if (!_isLocalHeaderLoaded)
+                {
+                    await LoadLocalHeaderAsync(cancellationToken);
+                    _isLocalHeaderLoaded = true;
+                }
+            }
+            finally
+            {
+                _asyncHeaderSemaphore.Release();
+            }
         }
         return await base.GetCompressedStreamAsync(cancellationToken);
     }
 
-    private void LoadLocalHeader() =>
-        Header = _headerFactory.GetLocalHeader(BaseStream, (DirectoryEntryHeader)Header);
+    private void LoadLocalHeader()
+    {
+        // Use an independent stream for loading the header if multi-threading is enabled
+        Stream streamToUse = BaseStream;
+        bool disposeStream = false;
 
-    private async ValueTask LoadLocalHeaderAsync(CancellationToken cancellationToken = default) =>
-        Header = await _headerFactory.GetLocalHeaderAsync(BaseStream, (DirectoryEntryHeader)Header);
+        if (
+            BaseStream is SourceStream sourceStream
+            && sourceStream.IsFileMode
+            && sourceStream.ReaderOptions.EnableMultiThreadedExtraction
+        )
+        {
+            var independentStream = sourceStream.CreateIndependentStream(0);
+            if (independentStream is not null)
+            {
+                streamToUse = independentStream;
+                disposeStream = true;
+            }
+        }
+        else
+        {
+            // Check if BaseStream wraps a FileStream
+            Stream? underlyingStream = BaseStream;
+            if (BaseStream is IStreamStack streamStack)
+            {
+                underlyingStream = streamStack.BaseStream();
+            }
+
+            if (underlyingStream is FileStream fileStream)
+            {
+                streamToUse = new FileStream(
+                    fileStream.Name,
+                    FileMode.Open,
+                    FileAccess.Read,
+                    FileShare.Read
+                );
+                disposeStream = true;
+            }
+        }
+
+        try
+        {
+            Header = _headerFactory.GetLocalHeader(streamToUse, (DirectoryEntryHeader)Header);
+        }
+        finally
+        {
+            if (disposeStream)
+            {
+                streamToUse.Dispose();
+            }
+        }
+    }
+
+    private async ValueTask LoadLocalHeaderAsync(CancellationToken cancellationToken = default)
+    {
+        // Use an independent stream for loading the header if multi-threading is enabled
+        Stream streamToUse = BaseStream;
+        bool disposeStream = false;
+
+        if (
+            BaseStream is SourceStream sourceStream
+            && sourceStream.IsFileMode
+            && sourceStream.ReaderOptions.EnableMultiThreadedExtraction
+        )
+        {
+            var independentStream = sourceStream.CreateIndependentStream(0);
+            if (independentStream is not null)
+            {
+                streamToUse = independentStream;
+                disposeStream = true;
+            }
+        }
+        else
+        {
+            // Check if BaseStream wraps a FileStream
+            Stream? underlyingStream = BaseStream;
+            if (BaseStream is IStreamStack streamStack)
+            {
+                underlyingStream = streamStack.BaseStream();
+            }
+
+            if (underlyingStream is FileStream fileStream)
+            {
+                streamToUse = new FileStream(
+                    fileStream.Name,
+                    FileMode.Open,
+                    FileAccess.Read,
+                    FileShare.Read
+                );
+                disposeStream = true;
+            }
+        }
+
+        try
+        {
+            Header = await _headerFactory.GetLocalHeaderAsync(
+                streamToUse,
+                (DirectoryEntryHeader)Header
+            );
+        }
+        finally
+        {
+            if (disposeStream)
+            {
+                streamToUse.Dispose();
+            }
+        }
+    }
 
     protected override Stream CreateBaseStream()
     {
-        BaseStream.Position = Header.DataStartPosition.NotNull();
+        // If BaseStream is a SourceStream in file mode with multi-threading enabled,
+        // create an independent stream to support concurrent extraction
+        if (
+            BaseStream is SourceStream sourceStream
+            && sourceStream.IsFileMode
+            && sourceStream.ReaderOptions.EnableMultiThreadedExtraction
+        )
+        {
+            // Create a new independent stream for this entry
+            var independentStream = sourceStream.CreateIndependentStream(0);
+            if (independentStream is not null)
+            {
+                independentStream.Position = Header.DataStartPosition.NotNull();
+                return independentStream;
+            }
+        }
 
+        // Check if BaseStream wraps a FileStream (for multi-volume archives)
+        Stream? underlyingStream = BaseStream;
+        if (BaseStream is IStreamStack streamStack)
+        {
+            underlyingStream = streamStack.BaseStream();
+        }
+
+        if (underlyingStream is FileStream fileStream)
+        {
+            // Create a new independent stream from the file
+            var independentStream = new FileStream(
+                fileStream.Name,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.Read
+            );
+            independentStream.Position = Header.DataStartPosition.NotNull();
+            return independentStream;
+        }
+
+        // Fall back to existing behavior for stream-based sources
+        BaseStream.Position = Header.DataStartPosition.NotNull();
         return BaseStream;
     }
 }

src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Buffers;
 using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
@@ -16,6 +17,8 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
     private const int MAX_SEARCH_LENGTH_FOR_EOCD = 65557;
     private bool _zip64;
 
+    private static readonly byte[] needle = { 0x06, 0x05, 0x4b, 0x50 };
+
     internal SeekableZipHeaderFactory(string? password, IArchiveEncoding archiveEncoding)
         : base(StreamingMode.Seekable, password, archiveEncoding) { }
 
@@ -153,74 +156,7 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
         }
     }
 
-    internal async IAsyncEnumerable<ZipHeader> ReadSeekableHeaderAsync(Stream stream, bool useSync)
-    {
-        var reader = new AsyncBinaryReader(stream);
-
-        await SeekBackToHeaderAsync(stream, reader);
-
-        var eocd_location = stream.Position;
-        var entry = new DirectoryEndHeader();
-        await entry.Read(reader);
-
-        if (entry.IsZip64)
-        {
-            _zip64 = true;
-
-            // ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR should be before the EOCD
-            stream.Seek(eocd_location - ZIP64_EOCD_LENGTH - 4, SeekOrigin.Begin);
-            var zip64_locator = await reader.ReadUInt32Async();
-            if (zip64_locator != ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR)
-            {
-                throw new ArchiveException("Failed to locate the Zip64 Directory Locator");
-            }
-
-            var zip64Locator = new Zip64DirectoryEndLocatorHeader();
-            await zip64Locator.Read(reader);
-
-            stream.Seek(zip64Locator.RelativeOffsetOfTheEndOfDirectoryRecord, SeekOrigin.Begin);
-            var zip64Signature = await reader.ReadUInt32Async();
-            if (zip64Signature != ZIP64_END_OF_CENTRAL_DIRECTORY)
-            {
-                throw new ArchiveException("Failed to locate the Zip64 Header");
-            }
-
-            var zip64Entry = new Zip64DirectoryEndHeader();
-            await zip64Entry.Read(reader);
-            stream.Seek(zip64Entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
-        }
-        else
-        {
-            stream.Seek(entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
-        }
-
-        var position = stream.Position;
-        while (true)
-        {
-            stream.Position = position;
-            var signature = await reader.ReadUInt32Async();
-            var nextHeader = await ReadHeader(signature, reader, _zip64);
-            position = stream.Position;
-
-            if (nextHeader is null)
-            {
-                yield break;
-            }
-
-            if (nextHeader is DirectoryEntryHeader entryHeader)
-            {
-                //entry could be zero bytes so we need to know that.
-                entryHeader.HasData = entryHeader.CompressedSize != 0;
-                yield return entryHeader;
-            }
-            else if (nextHeader is DirectoryEndHeader endHeader)
-            {
-                yield return endHeader;
-            }
-        }
-    }
-
-    private static bool IsMatch(byte[] haystack, int position, byte[] needle)
+    private static bool IsMatch(Span<byte> haystack, int position, byte[] needle)
     {
         for (var i = 0; i < needle.Length; i++)
         {
@@ -247,29 +183,35 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
             stream.Length < MAX_SEARCH_LENGTH_FOR_EOCD
                 ? (int)stream.Length
                 : MAX_SEARCH_LENGTH_FOR_EOCD;
-        // We search for marker in reverse to find the first occurance
-        byte[] needle = { 0x06, 0x05, 0x4b, 0x50 };
 
         stream.Seek(-len, SeekOrigin.End);
+        var seek = ArrayPool<byte>.Shared.Rent(len);
 
-        var seek = await reader.ReadBytesAsync(len);
-
-        // Search in reverse
-        Array.Reverse(seek);
-
-        // don't exclude the minimum eocd region, otherwise you fail to locate the header in empty zip files
-        var max_search_area = len; // - MINIMUM_EOCD_LENGTH;
-
-        for (var pos_from_end = 0; pos_from_end < max_search_area; ++pos_from_end)
+        try
         {
-            if (IsMatch(seek, pos_from_end, needle))
-            {
-                stream.Seek(-pos_from_end, SeekOrigin.End);
-                return;
-            }
-        }
+            await reader.ReadBytesAsync(seek, 0, len, default);
+            var memory = new Memory<byte>(seek, 0, len);
+            var span = memory.Span;
+            span.Reverse();
 
-        throw new ArchiveException("Failed to locate the Zip Header");
+            // don't exclude the minimum eocd region, otherwise you fail to locate the header in empty zip files
+            var max_search_area = len; // - MINIMUM_EOCD_LENGTH;
+
+            for (var pos_from_end = 0; pos_from_end < max_search_area; ++pos_from_end)
+            {
+                if (IsMatch(span, pos_from_end, needle))
+                {
+                    stream.Seek(-pos_from_end, SeekOrigin.End);
+                    return;
+                }
+            }
+
+            throw new ArchiveException("Failed to locate the Zip Header");
+        }
+        finally
+        {
+            ArrayPool<byte>.Shared.Return(seek);
+        }
     }
 
     private static void SeekBackToHeader(Stream stream, BinaryReader reader)
@@ -286,9 +228,6 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
             stream.Length < MAX_SEARCH_LENGTH_FOR_EOCD
                 ? (int)stream.Length
                 : MAX_SEARCH_LENGTH_FOR_EOCD;
-        // We search for marker in reverse to find the first occurance
-        byte[] needle = { 0x06, 0x05, 0x4b, 0x50 };
-
         stream.Seek(-len, SeekOrigin.End);
 
         var seek = reader.ReadBytes(len);

src/SharpCompress/Common/Zip/WinzipAesEncryptionData.cs

@@ -20,7 +20,7 @@ internal class WinzipAesEncryptionData
     {
         _keySize = keySize;
 
-#if NETFRAMEWORK || NETSTANDARD2_0
+#if LEGACY_DOTNET
         var rfc2898 = new Rfc2898DeriveBytes(password, salt, RFC2898_ITERATIONS);
         KeyBytes = rfc2898.GetBytes(KeySizeInBytes);
         IvBytes = rfc2898.GetBytes(KeySizeInBytes);

src/SharpCompress/Common/Zip/ZipHeaderFactory.cs

@@ -79,7 +79,7 @@ internal class ZipHeaderFactory
                 }
                 else
                 {
-                    await reader.ReadBytesAsync(zip64 ? 20 : 12);
+                    await reader.SkipAsync(zip64 ? 20 : 12);
                 }
                 return null;
             }

src/SharpCompress/Compressors/BZip2/BZip2Stream.cs

@@ -98,7 +98,7 @@ public sealed class BZip2Stream : Stream, IStreamStack
 
     public override void SetLength(long value) => stream.SetLength(value);
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
 
     public override int Read(Span<byte> buffer) => stream.Read(buffer);
 

src/SharpCompress/Compressors/Deflate/DeflateStream.cs

@@ -299,7 +299,7 @@ public class DeflateStream : Stream, IStreamStack
         await _baseStream.FlushAsync(cancellationToken).ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
     {
         if (_disposed)
@@ -370,7 +370,7 @@ public class DeflateStream : Stream, IStreamStack
             .ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default
@@ -461,7 +461,7 @@ public class DeflateStream : Stream, IStreamStack
             .ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask WriteAsync(
         ReadOnlyMemory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Deflate/GZipStream.cs

@@ -345,7 +345,7 @@ public class GZipStream : Stream, IStreamStack
         return n;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default
@@ -454,7 +454,7 @@ public class GZipStream : Stream, IStreamStack
         await BaseStream.WriteAsync(buffer, offset, count, cancellationToken).ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask WriteAsync(
         ReadOnlyMemory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Deflate/Inflate.cs

@@ -64,6 +64,7 @@
 // -----------------------------------------------------------------------
 
 using System;
+using System.Buffers;
 using SharpCompress.Algorithms;
 
 namespace SharpCompress.Compressors.Deflate;
@@ -116,14 +117,14 @@ internal sealed class InflateBlocks
     internal int readAt; // window read pointer
     internal int table; // table lengths (14 bits)
     internal int[] tb = new int[1]; // bit length decoding tree
-    internal byte[] window; // sliding window
+    internal IMemoryOwner<byte> window; // sliding window
     internal int writeAt; // window write pointer
 
     internal InflateBlocks(ZlibCodec codec, object checkfn, int w)
     {
         _codec = codec;
         hufts = new int[MANY * 3];
-        window = new byte[w];
+        window = MemoryPool<byte>.Shared.Rent(w);
         end = w;
         this.checkfn = checkfn;
         mode = InflateBlockMode.TYPE;
@@ -340,7 +341,7 @@ internal sealed class InflateBlocks
                     {
                         t = m;
                     }
-                    Array.Copy(_codec.InputBuffer, p, window, q, t);
+                    _codec.InputBuffer.AsSpan(p, t).CopyTo(window.Memory.Span.Slice(q));
                     p += t;
                     n -= t;
                     q += t;
@@ -715,13 +716,14 @@ internal sealed class InflateBlocks
     internal void Free()
     {
         Reset();
+        window?.Dispose();
         window = null;
         hufts = null;
     }
 
     internal void SetDictionary(byte[] d, int start, int n)
     {
-        Array.Copy(d, start, window, 0, n);
+        d.AsSpan(start, n).CopyTo(window.Memory.Span.Slice(0, n));
         readAt = writeAt = n;
     }
 
@@ -774,11 +776,16 @@ internal sealed class InflateBlocks
             // update check information
             if (checkfn != null)
             {
-                _codec._adler32 = check = Adler32.Calculate(check, window.AsSpan(readAt, nBytes));
+                _codec._adler32 = check = Adler32.Calculate(
+                    check,
+                    window.Memory.Span.Slice(readAt, nBytes)
+                );
             }
 
             // copy as far as end of window
-            Array.Copy(window, readAt, _codec.OutputBuffer, _codec.NextOut, nBytes);
+            window
+                .Memory.Span.Slice(readAt, nBytes)
+                .CopyTo(_codec.OutputBuffer.AsSpan(_codec.NextOut));
             _codec.NextOut += nBytes;
             readAt += nBytes;
 
@@ -1213,7 +1220,7 @@ internal sealed class InflateCodes
                             }
                         }
 
-                        blocks.window[q++] = blocks.window[f++];
+                        blocks.window.Memory.Span[q++] = blocks.window.Memory.Span[f++];
                         m--;
 
                         if (f == blocks.end)
@@ -1259,7 +1266,7 @@ internal sealed class InflateCodes
                     }
                     r = ZlibConstants.Z_OK;
 
-                    blocks.window[q++] = (byte)lit;
+                    blocks.window.Memory.Span[q++] = (byte)lit;
                     m--;
 
                     mode = START;
@@ -1396,7 +1403,7 @@ internal sealed class InflateCodes
                 b >>= (tp[tp_index_t_3 + 1]);
                 k -= (tp[tp_index_t_3 + 1]);
 
-                s.window[q++] = (byte)tp[tp_index_t_3 + 2];
+                s.window.Memory.Span[q++] = (byte)tp[tp_index_t_3 + 2];
                 m--;
                 continue;
             }
@@ -1461,13 +1468,14 @@ internal sealed class InflateCodes
                                 r = q - d;
                                 if (q - r > 0 && 2 > (q - r))
                                 {
-                                    s.window[q++] = s.window[r++]; // minimum count is three,
-                                    s.window[q++] = s.window[r++]; // so unroll loop a little
+                                    s.window.Memory.Span[q++] = s.window.Memory.Span[r++]; // minimum count is three,
+                                    s.window.Memory.Span[q++] = s.window.Memory.Span[r++]; // so unroll loop a little
                                     c -= 2;
                                 }
                                 else
                                 {
-                                    Array.Copy(s.window, r, s.window, q, 2);
+                                    s.window.Memory.Span.Slice(r, 2)
+                                        .CopyTo(s.window.Memory.Span.Slice(q));
                                     q += 2;
                                     r += 2;
                                     c -= 2;
@@ -1490,12 +1498,13 @@ internal sealed class InflateCodes
                                     {
                                         do
                                         {
-                                            s.window[q++] = s.window[r++];
+                                            s.window.Memory.Span[q++] = s.window.Memory.Span[r++];
                                         } while (--e != 0);
                                     }
                                     else
                                     {
-                                        Array.Copy(s.window, r, s.window, q, e);
+                                        s.window.Memory.Span.Slice(r, e)
+                                            .CopyTo(s.window.Memory.Span.Slice(q));
                                         q += e;
                                         r += e;
                                         e = 0;
@@ -1509,12 +1518,13 @@ internal sealed class InflateCodes
                             {
                                 do
                                 {
-                                    s.window[q++] = s.window[r++];
+                                    s.window.Memory.Span[q++] = s.window.Memory.Span[r++];
                                 } while (--c != 0);
                             }
                             else
                             {
-                                Array.Copy(s.window, r, s.window, q, c);
+                                s.window.Memory.Span.Slice(r, c)
+                                    .CopyTo(s.window.Memory.Span.Slice(q));
                                 q += c;
                                 r += c;
                                 c = 0;
@@ -1560,7 +1570,7 @@ internal sealed class InflateCodes
                     {
                         b >>= (tp[tp_index_t_3 + 1]);
                         k -= (tp[tp_index_t_3 + 1]);
-                        s.window[q++] = (byte)tp[tp_index_t_3 + 2];
+                        s.window.Memory.Span[q++] = (byte)tp[tp_index_t_3 + 2];
                         m--;
                         break;
                     }

src/SharpCompress/Compressors/Deflate/ZlibBaseStream.cs

@@ -552,7 +552,7 @@ internal class ZlibBaseStream : Stream, IStreamStack
         }
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
     {
         if (isDisposed)
@@ -1171,7 +1171,7 @@ internal class ZlibBaseStream : Stream, IStreamStack
         return rc;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Deflate/ZlibConstants.cs

@@ -108,13 +108,9 @@ internal static class ZlibConstants
     public const int Z_BUF_ERROR = -5;
 
     /// <summary>
-    /// The size of the working buffer used in the ZlibCodec class. Defaults to 8192 bytes.
+    /// The size of the working buffer used in the ZlibCodec class. Defaults to 16384 bytes.
     /// </summary>
-#if NETCF
-    public const int WorkingBufferSizeDefault = 8192;
-#else
     public const int WorkingBufferSizeDefault = 16384;
-#endif
 
     /// <summary>
     /// The minimum size of the working buffer used in the ZlibCodec class.  Currently it is 128 bytes.

src/SharpCompress/Compressors/Deflate/ZlibStream.cs

@@ -277,7 +277,7 @@ public class ZlibStream : Stream, IStreamStack
         await _baseStream.FlushAsync(cancellationToken).ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
     {
         if (_disposed)
@@ -347,7 +347,7 @@ public class ZlibStream : Stream, IStreamStack
             .ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default
@@ -431,7 +431,7 @@ public class ZlibStream : Stream, IStreamStack
             .ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask WriteAsync(
         ReadOnlyMemory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Deflate64/Deflate64Stream.cs

@@ -200,7 +200,7 @@ public sealed class Deflate64Stream : Stream, IStreamStack
         return count - remainingCount;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/LZMA/LZipStream.cs

@@ -163,7 +163,7 @@ public sealed class LZipStream : Stream, IStreamStack
 
     public override void SetLength(long value) => throw new NotImplementedException();
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
 
     public override ValueTask<int> ReadAsync(
         Memory<byte> buffer,

src/SharpCompress/Compressors/LZMA/LzmaDecoder.cs

@@ -201,7 +201,7 @@ public class Decoder : ICoder, ISetDecoderProperties // ,System.IO.Stream
         }
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     [MemberNotNull(nameof(_outWindow))]
 #endif
     private void CreateDictionary()

src/SharpCompress/Compressors/LZMA/LzmaStream.cs

@@ -632,7 +632,7 @@ public class LzmaStream : Stream, IStreamStack
         return total;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Rar/MultiVolumeReadOnlyStream.cs

@@ -185,7 +185,7 @@ internal sealed class MultiVolumeReadOnlyStream : Stream, IStreamStack
         return totalRead;
     }
 
-#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         System.Threading.CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Rar/RarBLAKE2spStream.cs

@@ -385,7 +385,7 @@ internal class RarBLAKE2spStream : RarStream, IStreamStack
         return result;
     }
 
-#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         System.Threading.CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Rar/RarCrcStream.cs

@@ -129,7 +129,7 @@ internal class RarCrcStream : RarStream, IStreamStack
         return result;
     }
 
-#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         System.Threading.CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Rar/RarStream.cs

@@ -87,10 +87,10 @@ internal class RarStream : Stream, IStreamStack
 #endif
                 ArrayPool<byte>.Shared.Return(this.tmpBuffer);
                 this.tmpBuffer = null;
+                readStream.Dispose();
             }
             isDisposed = true;
             base.Dispose(disposing);
-            readStream.Dispose();
         }
     }
 
@@ -189,7 +189,7 @@ internal class RarStream : Stream, IStreamStack
         return outTotal;
     }
 
-#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+#if !LEGACY_DOTNET
     public override async System.Threading.Tasks.ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         System.Threading.CancellationToken cancellationToken = default

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs

@@ -126,17 +126,12 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
 
     private FileHeader fileHeader;
 
-    private void Init(byte[] window)
+    private void Init()
     {
-        if (this.window is null && window is null)
+        if (this.window is null)
         {
             this.window = ArrayPool<byte>.Shared.Rent(PackDef.MAXWINSIZE);
         }
-        else if (window is not null)
-        {
-            this.window = window;
-            externalWindow = true;
-        }
         inAddr = 0;
         UnpInitData(false);
     }
@@ -149,7 +144,7 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         this.writeStream = writeStream;
         if (!fileHeader.IsSolid)
         {
-            Init(null);
+            Init();
         }
         suspended = false;
         DoUnpack();
@@ -168,7 +163,7 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         this.writeStream = writeStream;
         if (!fileHeader.IsSolid)
         {
-            Init(null);
+            Init();
         }
         suspended = false;
         await DoUnpackAsync(cancellationToken).ConfigureAwait(false);

src/SharpCompress/Compressors/ZStandard/CompressionStream.cs

@@ -74,7 +74,7 @@ public class CompressionStream : Stream
 
     ~CompressionStream() => Dispose(false);
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
 #else
     public async ValueTask DisposeAsync()
@@ -145,7 +145,7 @@ public class CompressionStream : Stream
     public override void Write(byte[] buffer, int offset, int count) =>
         Write(new ReadOnlySpan<byte>(buffer, offset, count));
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
     public override void Write(ReadOnlySpan<byte> buffer) =>
         WriteInternal(buffer, ZSTD_EndDirective.ZSTD_e_continue);
 #else
@@ -176,7 +176,7 @@ public class CompressionStream : Stream
         );
     }
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
     private async ValueTask WriteInternalAsync(
         ReadOnlyMemory<byte>? buffer,
         ZSTD_EndDirective directive,
@@ -218,7 +218,7 @@ public class CompressionStream : Stream
         );
     }
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
 
     public override Task WriteAsync(
         byte[] buffer,

src/SharpCompress/Compressors/ZStandard/DecompressionStream.cs

@@ -105,7 +105,7 @@ public class DecompressionStream : Stream
     public override int Read(byte[] buffer, int offset, int count) =>
         Read(new Span<byte>(buffer, offset, count));
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
     public override int Read(Span<byte> buffer)
 #else
     public int Read(Span<byte> buffer)
@@ -158,7 +158,7 @@ public class DecompressionStream : Stream
         }
     }
 
-#if !NETSTANDARD2_0 && !NETFRAMEWORK
+#if !LEGACY_DOTNET
     public override Task<int> ReadAsync(
         byte[] buffer,
         int offset,
@@ -276,7 +276,7 @@ public class DecompressionStream : Stream
             throw new ObjectDisposedException(nameof(DecompressionStream));
     }
 
-#if NETSTANDARD2_0 || NETFRAMEWORK
+#if LEGACY_DOTNET
     public virtual Task DisposeAsync()
     {
         try

src/SharpCompress/Compressors/ZStandard/UnsafeHelper.cs

@@ -16,7 +16,7 @@ public static unsafe class UnsafeHelper
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void* malloc(ulong size)
     {
-#if NET6_0_OR_GREATER
+#if NET8_0_OR_GREATER
         var ptr = NativeMemory.Alloc((nuint)size);
 #else
         var ptr = (void*)Marshal.AllocHGlobal((nint)size);
@@ -31,7 +31,7 @@ public static unsafe class UnsafeHelper
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void* calloc(ulong num, ulong size)
     {
-#if NET6_0_OR_GREATER
+#if NET8_0_OR_GREATER
         return NativeMemory.AllocZeroed((nuint)num, (nuint)size);
 #else
         var total = num * size;
@@ -53,7 +53,7 @@ public static unsafe class UnsafeHelper
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void free(void* ptr)
     {
-#if NET6_0_OR_GREATER
+#if NET8_0_OR_GREATER
         NativeMemory.Free(ptr);
 #else
         Marshal.FreeHGlobal((IntPtr)ptr);

src/SharpCompress/Crypto/Crc32Stream.cs

@@ -70,7 +70,7 @@ public sealed class Crc32Stream : Stream, IStreamStack
 
     public override void SetLength(long value) => throw new NotSupportedException();
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
 
     public override void Write(ReadOnlySpan<byte> buffer)
     {

src/SharpCompress/Factories/AceFactory.cs

@@ -30,13 +30,17 @@ namespace SharpCompress.Factories
         ) => AceHeader.IsArchive(stream);
 
         public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-            AceReader.Open(stream, options);
+            AceReader.OpenReader(stream, options);
 
-        public ValueTask<IAsyncReader> OpenReaderAsync(
+        public IAsyncReader OpenAsyncReader(
             Stream stream,
             ReaderOptions? options,
             CancellationToken cancellationToken = default
-        ) => new(AceReader.Open(stream, options));
+        )
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            return (IAsyncReader)AceReader.OpenReader(stream, options);
+        }
 
         public override ValueTask<bool> IsArchiveAsync(
             Stream stream,

src/SharpCompress/Factories/ArcFactory.cs

@@ -42,13 +42,17 @@ namespace SharpCompress.Factories
         }
 
         public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-            ArcReader.Open(stream, options);
+            ArcReader.OpenReader(stream, options);
 
-        public ValueTask<IAsyncReader> OpenReaderAsync(
+        public IAsyncReader OpenAsyncReader(
             Stream stream,
             ReaderOptions? options,
             CancellationToken cancellationToken = default
-        ) => new(ArcReader.Open(stream, options));
+        )
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            return (IAsyncReader)ArcReader.OpenReader(stream, options);
+        }
 
         public override ValueTask<bool> IsArchiveAsync(
             Stream stream,

src/SharpCompress/Factories/ArjFactory.cs

@@ -33,13 +33,17 @@ namespace SharpCompress.Factories
         }
 
         public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-            ArjReader.Open(stream, options);
+            ArjReader.OpenReader(stream, options);
 
-        public ValueTask<IAsyncReader> OpenReaderAsync(
+        public IAsyncReader OpenAsyncReader(
             Stream stream,
             ReaderOptions? options,
             CancellationToken cancellationToken = default
-        ) => new(ArjReader.Open(stream, options));
+        )
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            return (IAsyncReader)ArjReader.OpenReader(stream, options);
+        }
 
         public override ValueTask<bool> IsArchiveAsync(
             Stream stream,

src/SharpCompress/Factories/Factory.cs

@@ -133,10 +133,7 @@ public abstract class Factory : IFactory
             )
             {
                 ((IStreamStack)stream).StackSeek(pos);
-                return (
-                    true,
-                    await readerFactory.OpenReaderAsync(stream, options, cancellationToken)
-                );
+                return (true, readerFactory.OpenAsyncReader(stream, options, cancellationToken));
             }
         }
 

src/SharpCompress/Factories/GZipFactory.cs

@@ -61,15 +61,12 @@ public class GZipFactory
     #region IArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        GZipArchive.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        GZipArchive.OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => GZipArchive.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
     public override ValueTask<bool> IsArchiveAsync(
         Stream stream,
@@ -78,41 +75,48 @@ public class GZipFactory
     ) => new(IsArchive(stream, password, bufferSize));
 
     /// <inheritdoc/>
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        GZipArchive.Open(fileInfo, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => GZipArchive.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 
     #endregion
 
     #region IMultiArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null) =>
-        GZipArchive.Open(streams, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => GZipArchive.OpenAsync(streams, readerOptions, cancellationToken);
+        ReaderOptions? readerOptions = null
+    ) => GZipArchive.OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null) =>
-        GZipArchive.Open(fileInfos, readerOptions);
+    public IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null
+    ) => (IAsyncArchive)OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    ) => GZipArchive.OpenArchive(fileInfos, readerOptions);
+
+    /// <inheritdoc/>
+    public IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => GZipArchive.OpenAsync(fileInfos, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
 
     #endregion
 
@@ -150,25 +154,29 @@ public class GZipFactory
 
     /// <inheritdoc/>
     public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-        GZipReader.Open(stream, options);
+        GZipReader.OpenReader(stream, options);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncReader> OpenReaderAsync(
+    public IAsyncReader OpenAsyncReader(
         Stream stream,
         ReaderOptions? options,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(GZipReader.Open(stream, options));
+        return (IAsyncReader)GZipReader.OpenReader(stream, options);
     }
 
+    /// <inheritdoc/>
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        GZipArchive.OpenArchive(fileInfo, readerOptions);
+
     #endregion
 
     #region IWriterFactory
 
     /// <inheritdoc/>
-    public IWriter Open(Stream stream, WriterOptions writerOptions)
+    public IWriter OpenWriter(Stream stream, WriterOptions writerOptions)
     {
         if (writerOptions.CompressionType != CompressionType.GZip)
         {
@@ -178,14 +186,18 @@ public class GZipFactory
     }
 
     /// <inheritdoc/>
-    public ValueTask<IWriter> OpenAsync(
+    public IAsyncWriter OpenAsyncWriter(
         Stream stream,
         WriterOptions writerOptions,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, writerOptions));
+        if (writerOptions.CompressionType != CompressionType.GZip)
+        {
+            throw new InvalidFormatException("GZip archives only support GZip compression type.");
+        }
+        return (IAsyncWriter)OpenWriter(stream, writerOptions);
     }
 
     #endregion
@@ -193,7 +205,7 @@ public class GZipFactory
     #region IWriteableArchiveFactory
 
     /// <inheritdoc/>
-    public IWritableArchive CreateWriteableArchive() => GZipArchive.Create();
+    public IWritableArchive CreateArchive() => GZipArchive.CreateArchive();
 
     #endregion
 }

src/SharpCompress/Factories/RarFactory.cs

@@ -46,26 +46,27 @@ public class RarFactory : Factory, IArchiveFactory, IMultiArchiveFactory, IReade
     #region IArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        RarArchive.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        RarArchive.OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => RarArchive.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        RarArchive.Open(fileInfo, readerOptions);
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        RarArchive.OpenArchive(fileInfo, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => RarArchive.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 
     public override ValueTask<bool> IsArchiveAsync(
         Stream stream,
@@ -78,26 +79,33 @@ public class RarFactory : Factory, IArchiveFactory, IMultiArchiveFactory, IReade
     #region IMultiArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null) =>
-        RarArchive.Open(streams, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => RarArchive.OpenAsync(streams, readerOptions, cancellationToken);
+        ReaderOptions? readerOptions = null
+    ) => RarArchive.OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null) =>
-        RarArchive.Open(fileInfos, readerOptions);
+    public IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null
+    ) => (IAsyncArchive)OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    ) => RarArchive.OpenArchive(fileInfos, readerOptions);
+
+    /// <inheritdoc/>
+    public IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => RarArchive.OpenAsync(fileInfos, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
 
     #endregion
 
@@ -105,17 +113,17 @@ public class RarFactory : Factory, IArchiveFactory, IMultiArchiveFactory, IReade
 
     /// <inheritdoc/>
     public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-        RarReader.Open(stream, options);
+        RarReader.OpenReader(stream, options);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncReader> OpenReaderAsync(
+    public IAsyncReader OpenAsyncReader(
         Stream stream,
         ReaderOptions? options,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(RarReader.Open(stream, options));
+        return (IAsyncReader)RarReader.OpenReader(stream, options);
     }
 
     #endregion

src/SharpCompress/Factories/SevenZipFactory.cs

@@ -41,26 +41,27 @@ public class SevenZipFactory : Factory, IArchiveFactory, IMultiArchiveFactory
     #region IArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        SevenZipArchive.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        SevenZipArchive.OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => SevenZipArchive.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        SevenZipArchive.Open(fileInfo, readerOptions);
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        SevenZipArchive.OpenArchive(fileInfo, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => SevenZipArchive.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 
     public override ValueTask<bool> IsArchiveAsync(
         Stream stream,
@@ -73,26 +74,33 @@ public class SevenZipFactory : Factory, IArchiveFactory, IMultiArchiveFactory
     #region IMultiArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null) =>
-        SevenZipArchive.Open(streams, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => SevenZipArchive.OpenAsync(streams, readerOptions, cancellationToken);
+        ReaderOptions? readerOptions = null
+    ) => SevenZipArchive.OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null) =>
-        SevenZipArchive.Open(fileInfos, readerOptions);
+    public IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null
+    ) => (IAsyncArchive)OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    ) => SevenZipArchive.OpenArchive(fileInfos, readerOptions);
+
+    /// <inheritdoc/>
+    public IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => SevenZipArchive.OpenAsync(fileInfos, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
 
     #endregion
 

src/SharpCompress/Factories/TarFactory.cs

@@ -72,52 +72,60 @@ public class TarFactory
     #region IArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        TarArchive.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        TarArchive.OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => TarArchive.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        TarArchive.Open(fileInfo, readerOptions);
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        TarArchive.OpenArchive(fileInfo, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => TarArchive.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 
     #endregion
 
     #region IMultiArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null) =>
-        TarArchive.Open(streams, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => TarArchive.OpenAsync(streams, readerOptions, cancellationToken);
+        ReaderOptions? readerOptions = null
+    ) => TarArchive.OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null) =>
-        TarArchive.Open(fileInfos, readerOptions);
+    public IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null
+    ) => (IAsyncArchive)OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    ) => TarArchive.OpenArchive(fileInfos, readerOptions);
+
+    /// <inheritdoc/>
+    public IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => TarArchive.OpenAsync(fileInfos, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
 
     #endregion
 
@@ -268,17 +276,17 @@ public class TarFactory
 
     /// <inheritdoc/>
     public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-        TarReader.Open(stream, options);
+        TarReader.OpenReader(stream, options);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncReader> OpenReaderAsync(
+    public IAsyncReader OpenAsyncReader(
         Stream stream,
         ReaderOptions? options,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(TarReader.Open(stream, options));
+        return (IAsyncReader)TarReader.OpenReader(stream, options);
     }
 
     #endregion
@@ -286,18 +294,18 @@ public class TarFactory
     #region IWriterFactory
 
     /// <inheritdoc/>
-    public IWriter Open(Stream stream, WriterOptions writerOptions) =>
+    public IWriter OpenWriter(Stream stream, WriterOptions writerOptions) =>
         new TarWriter(stream, new TarWriterOptions(writerOptions));
 
     /// <inheritdoc/>
-    public ValueTask<IWriter> OpenAsync(
+    public IAsyncWriter OpenAsyncWriter(
         Stream stream,
         WriterOptions writerOptions,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, writerOptions));
+        return (IAsyncWriter)OpenWriter(stream, writerOptions);
     }
 
     #endregion
@@ -305,7 +313,7 @@ public class TarFactory
     #region IWriteableArchiveFactory
 
     /// <inheritdoc/>
-    public IWritableArchive CreateWriteableArchive() => TarArchive.Create();
+    public IWritableArchive CreateArchive() => TarArchive.CreateArchive();
 
     #endregion
 }

src/SharpCompress/Factories/ZipFactory.cs

@@ -139,52 +139,60 @@ public class ZipFactory
     #region IArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
-        ZipArchive.Open(stream, readerOptions);
+    public IArchive OpenArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        ZipArchive.OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
-        Stream stream,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => ZipArchive.OpenAsync(stream, readerOptions, cancellationToken);
+    public IAsyncArchive OpenAsyncArchive(Stream stream, ReaderOptions? readerOptions = null) =>
+        (IAsyncArchive)OpenArchive(stream, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
-        ZipArchive.Open(fileInfo, readerOptions);
+    public IArchive OpenArchive(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        ZipArchive.OpenArchive(fileInfo, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IAsyncArchive OpenAsyncArchive(
         FileInfo fileInfo,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => ZipArchive.OpenAsync(fileInfo, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfo, readerOptions);
+    }
 
     #endregion
 
     #region IMultiArchiveFactory
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<Stream> streams, ReaderOptions? readerOptions = null) =>
-        ZipArchive.Open(streams, readerOptions);
-
-    /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
         IReadOnlyList<Stream> streams,
-        ReaderOptions? readerOptions = null,
-        CancellationToken cancellationToken = default
-    ) => ZipArchive.OpenAsync(streams, readerOptions, cancellationToken);
+        ReaderOptions? readerOptions = null
+    ) => ZipArchive.OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public IArchive Open(IReadOnlyList<FileInfo> fileInfos, ReaderOptions? readerOptions = null) =>
-        ZipArchive.Open(fileInfos, readerOptions);
+    public IAsyncArchive OpenAsyncArchive(
+        IReadOnlyList<Stream> streams,
+        ReaderOptions? readerOptions = null
+    ) => (IAsyncArchive)OpenArchive(streams, readerOptions);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncArchive> OpenAsync(
+    public IArchive OpenArchive(
+        IReadOnlyList<FileInfo> fileInfos,
+        ReaderOptions? readerOptions = null
+    ) => ZipArchive.OpenArchive(fileInfos, readerOptions);
+
+    /// <inheritdoc/>
+    public IAsyncArchive OpenAsyncArchive(
         IReadOnlyList<FileInfo> fileInfos,
         ReaderOptions? readerOptions = null,
         CancellationToken cancellationToken = default
-    ) => ZipArchive.OpenAsync(fileInfos, readerOptions, cancellationToken);
+    )
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        return (IAsyncArchive)OpenArchive(fileInfos, readerOptions);
+    }
 
     #endregion
 
@@ -192,17 +200,17 @@ public class ZipFactory
 
     /// <inheritdoc/>
     public IReader OpenReader(Stream stream, ReaderOptions? options) =>
-        ZipReader.Open(stream, options);
+        ZipReader.OpenReader(stream, options);
 
     /// <inheritdoc/>
-    public ValueTask<IAsyncReader> OpenReaderAsync(
+    public IAsyncReader OpenAsyncReader(
         Stream stream,
         ReaderOptions? options,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(ZipReader.Open(stream, options));
+        return (IAsyncReader)ZipReader.OpenReader(stream, options);
     }
 
     #endregion
@@ -210,18 +218,18 @@ public class ZipFactory
     #region IWriterFactory
 
     /// <inheritdoc/>
-    public IWriter Open(Stream stream, WriterOptions writerOptions) =>
+    public IWriter OpenWriter(Stream stream, WriterOptions writerOptions) =>
         new ZipWriter(stream, new ZipWriterOptions(writerOptions));
 
     /// <inheritdoc/>
-    public ValueTask<IWriter> OpenAsync(
+    public IAsyncWriter OpenAsyncWriter(
         Stream stream,
         WriterOptions writerOptions,
         CancellationToken cancellationToken = default
     )
     {
         cancellationToken.ThrowIfCancellationRequested();
-        return new(Open(stream, writerOptions));
+        return (IAsyncWriter)OpenWriter(stream, writerOptions);
     }
 
     #endregion
@@ -229,7 +237,7 @@ public class ZipFactory
     #region IWriteableArchiveFactory
 
     /// <inheritdoc/>
-    public IWritableArchive CreateWriteableArchive() => ZipArchive.Create();
+    public IWritableArchive CreateArchive() => ZipArchive.CreateArchive();
 
     #endregion
 }

src/SharpCompress/IO/BufferedSubStream.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Buffers;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -28,13 +29,16 @@ internal class BufferedSubStream : SharpCompressStream, IStreamStack
 #if DEBUG_STREAMS
         this.DebugDispose(typeof(BufferedSubStream));
 #endif
-        if (disposing) { }
+        if (disposing)
+        {
+            ArrayPool<byte>.Shared.Return(_cache);
+        }
         base.Dispose(disposing);
     }
 
     private int _cacheOffset;
     private int _cacheLength;
-    private readonly byte[] _cache = new byte[32 << 10];
+    private readonly byte[] _cache = ArrayPool<byte>.Shared.Rent(32 << 10);
     private long origin;
 
     private long BytesLeftToRead { get; set; }
@@ -150,7 +154,7 @@ internal class BufferedSubStream : SharpCompressStream, IStreamStack
         return count;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/IO/ProgressReportingStream.cs

@@ -64,7 +64,7 @@ internal sealed class ProgressReportingStream : Stream
         return bytesRead;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override int Read(Span<byte> buffer)
     {
         var bytesRead = _baseStream.Read(buffer);
@@ -95,7 +95,7 @@ internal sealed class ProgressReportingStream : Stream
         return bytesRead;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default
@@ -147,7 +147,7 @@ internal sealed class ProgressReportingStream : Stream
         base.Dispose(disposing);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask DisposeAsync()
     {
         if (!_leaveOpen)

src/SharpCompress/IO/ReadOnlySubStream.cs

@@ -81,7 +81,7 @@ internal class ReadOnlySubStream : SharpCompressStream, IStreamStack
         return value;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override int Read(Span<byte> buffer)
     {
         var sliceLen = BytesLeftToRead < buffer.Length ? BytesLeftToRead : buffer.Length;
@@ -117,7 +117,7 @@ internal class ReadOnlySubStream : SharpCompressStream, IStreamStack
         return read;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,
         CancellationToken cancellationToken = default

src/SharpCompress/IO/SharpCompressStream.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Buffers;
-using System.Diagnostics;
 using System.IO;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -386,7 +384,7 @@ public class SharpCompressStream : Stream, IStreamStack
         await Stream.FlushAsync(cancellationToken).ConfigureAwait(false);
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
 
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,

src/SharpCompress/IO/SourceStream.cs

@@ -98,6 +98,30 @@ public class SourceStream : Stream, IStreamStack
 
     private Stream Current => _streams[_stream];
 
+    /// <summary>
+    /// Creates an independent stream for the specified volume index.
+    /// This allows multiple threads to read from different positions concurrently.
+    /// Only works when IsFileMode is true.
+    /// </summary>
+    /// <param name="volumeIndex">The volume index to create a stream for</param>
+    /// <returns>A new independent FileStream, or null if not in file mode or volume doesn't exist</returns>
+    public Stream? CreateIndependentStream(int volumeIndex)
+    {
+        if (!IsFileMode)
+        {
+            return null;
+        }
+
+        // Ensure the volume is loaded
+        if (!LoadStream(volumeIndex))
+        {
+            return null;
+        }
+
+        // Create a new independent stream from the FileInfo
+        return _files[volumeIndex].OpenRead();
+    }
+
     public bool LoadStream(int index) //ensure all parts to id are loaded
     {
         while (_streams.Count <= index)
@@ -289,7 +313,7 @@ public class SourceStream : Stream, IStreamStack
         return total - count;
     }
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !LEGACY_DOTNET
 
     public override async ValueTask<int> ReadAsync(
         Memory<byte> buffer,

src/SharpCompress/LazyAsyncReadOnlyCollection.cs

@@ -10,23 +10,23 @@ namespace SharpCompress;
 internal sealed class LazyAsyncReadOnlyCollection<T>(IAsyncEnumerable<T> source)
     : IAsyncEnumerable<T>
 {
-    private readonly List<T> backing = new();
-    private readonly IAsyncEnumerator<T> source = source.GetAsyncEnumerator();
-    private bool fullyLoaded;
+    private readonly List<T> _backing = new();
+    private readonly IAsyncEnumerator<T> _source = source.GetAsyncEnumerator();
+    private bool _fullyLoaded;
 
     private class LazyLoader(
         LazyAsyncReadOnlyCollection<T> lazyReadOnlyCollection,
         CancellationToken cancellationToken
     ) : IAsyncEnumerator<T>
     {
-        private bool disposed;
-        private int index = -1;
+        private bool _disposed;
+        private int _index = -1;
 
         public ValueTask DisposeAsync()
         {
-            if (!disposed)
+            if (!_disposed)
             {
-                disposed = true;
+                _disposed = true;
             }
             return default;
         }
@@ -34,27 +34,27 @@ internal sealed class LazyAsyncReadOnlyCollection<T>(IAsyncEnumerable<T> source)
         public async ValueTask<bool> MoveNextAsync()
         {
             cancellationToken.ThrowIfCancellationRequested();
-            if (index + 1 < lazyReadOnlyCollection.backing.Count)
+            if (_index + 1 < lazyReadOnlyCollection._backing.Count)
             {
-                index++;
+                _index++;
                 return true;
             }
             if (
-                !lazyReadOnlyCollection.fullyLoaded
-                && await lazyReadOnlyCollection.source.MoveNextAsync()
+                !lazyReadOnlyCollection._fullyLoaded
+                && await lazyReadOnlyCollection._source.MoveNextAsync()
             )
             {
-                lazyReadOnlyCollection.backing.Add(lazyReadOnlyCollection.source.Current);
-                index++;
+                lazyReadOnlyCollection._backing.Add(lazyReadOnlyCollection._source.Current);
+                _index++;
                 return true;
             }
-            lazyReadOnlyCollection.fullyLoaded = true;
+            lazyReadOnlyCollection._fullyLoaded = true;
             return false;
         }
 
         #region IEnumerator<T> Members
 
-        public T Current => lazyReadOnlyCollection.backing[index];
+        public T Current => lazyReadOnlyCollection._backing[_index];
 
         #endregion
 
@@ -62,9 +62,9 @@ internal sealed class LazyAsyncReadOnlyCollection<T>(IAsyncEnumerable<T> source)
 
         public void Dispose()
         {
-            if (!disposed)
+            if (!_disposed)
             {
-                disposed = true;
+                _disposed = true;
             }
         }
 
@@ -73,18 +73,18 @@ internal sealed class LazyAsyncReadOnlyCollection<T>(IAsyncEnumerable<T> source)
 
     internal async ValueTask EnsureFullyLoaded()
     {
-        if (!fullyLoaded)
+        if (!_fullyLoaded)
         {
             var loader = new LazyLoader(this, CancellationToken.None);
             while (await loader.MoveNextAsync())
             {
                 // Intentionally empty
             }
-            fullyLoaded = true;
+            _fullyLoaded = true;
         }
     }
 
-    internal IEnumerable<T> GetLoaded() => backing;
+    internal IEnumerable<T> GetLoaded() => _backing;
 
     #region ICollection<T> Members
 

src/SharpCompress/LazyReadOnlyCollection.cs

@@ -8,24 +8,24 @@ namespace SharpCompress;
 
 internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
 {
-    private readonly List<T> backing = new();
-    private readonly IEnumerator<T> source;
-    private bool fullyLoaded;
+    private readonly List<T> _backing = new();
+    private readonly IEnumerator<T> _source;
+    private bool _fullyLoaded;
 
-    public LazyReadOnlyCollection(IEnumerable<T> source) => this.source = source.GetEnumerator();
+    public LazyReadOnlyCollection(IEnumerable<T> source) => _source = source.GetEnumerator();
 
     private class LazyLoader : IEnumerator<T>
     {
-        private readonly LazyReadOnlyCollection<T> lazyReadOnlyCollection;
-        private bool disposed;
-        private int index = -1;
+        private readonly LazyReadOnlyCollection<T> _lazyReadOnlyCollection;
+        private bool _disposed;
+        private int _index = -1;
 
         internal LazyLoader(LazyReadOnlyCollection<T> lazyReadOnlyCollection) =>
-            this.lazyReadOnlyCollection = lazyReadOnlyCollection;
+            _lazyReadOnlyCollection = lazyReadOnlyCollection;
 
         #region IEnumerator<T> Members
 
-        public T Current => lazyReadOnlyCollection.backing[index];
+        public T Current => _lazyReadOnlyCollection._backing[_index];
 
         #endregion
 
@@ -33,9 +33,9 @@ internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
 
         public void Dispose()
         {
-            if (!disposed)
+            if (!_disposed)
             {
-                disposed = true;
+                _disposed = true;
             }
         }
 
@@ -47,18 +47,18 @@ internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
 
         public bool MoveNext()
         {
-            if (index + 1 < lazyReadOnlyCollection.backing.Count)
+            if (_index + 1 < _lazyReadOnlyCollection._backing.Count)
             {
-                index++;
+                _index++;
                 return true;
             }
-            if (!lazyReadOnlyCollection.fullyLoaded && lazyReadOnlyCollection.source.MoveNext())
+            if (!_lazyReadOnlyCollection._fullyLoaded && _lazyReadOnlyCollection._source.MoveNext())
             {
-                lazyReadOnlyCollection.backing.Add(lazyReadOnlyCollection.source.Current);
-                index++;
+                _lazyReadOnlyCollection._backing.Add(_lazyReadOnlyCollection._source.Current);
+                _index++;
                 return true;
             }
-            lazyReadOnlyCollection.fullyLoaded = true;
+            _lazyReadOnlyCollection._fullyLoaded = true;
             return false;
         }
 
@@ -69,14 +69,14 @@ internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
 
     internal void EnsureFullyLoaded()
     {
-        if (!fullyLoaded)
+        if (!_fullyLoaded)
         {
             this.ForEach(x => { });
-            fullyLoaded = true;
+            _fullyLoaded = true;
         }
     }
 
-    internal IEnumerable<T> GetLoaded() => backing;
+    internal IEnumerable<T> GetLoaded() => _backing;
 
     #region ICollection<T> Members
 
@@ -87,13 +87,13 @@ internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
     public bool Contains(T item)
     {
         EnsureFullyLoaded();
-        return backing.Contains(item);
+        return _backing.Contains(item);
     }
 
     public void CopyTo(T[] array, int arrayIndex)
     {
         EnsureFullyLoaded();
-        backing.CopyTo(array, arrayIndex);
+        _backing.CopyTo(array, arrayIndex);
     }
 
     public int Count
@@ -101,7 +101,7 @@ internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
         get
         {
             EnsureFullyLoaded();
-            return backing.Count;
+            return _backing.Count;
         }
     }
 

src/SharpCompress/NotNullExtensions.cs

@@ -21,7 +21,7 @@ internal static class NotNullExtensions
         return source.AsEnumerable();
     }
 
-#if NETFRAMEWORK || NETSTANDARD
+#if LEGACY_DOTNET
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static T NotNull<T>(this T? obj, string? message = null)
         where T : class

src/SharpCompress/Polyfills/AsyncEnumerableExtensions.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace SharpCompress;
@@ -29,9 +31,46 @@ public static class EnumerableExtensions
 
 public static class AsyncEnumerableExtensions
 {
+#if !NET10_0_OR_GREATER
     extension<T>(IAsyncEnumerable<T> source)
-        where T : notnull
     {
+        public async IAsyncEnumerable<TResult> Select<TResult>(Func<T, TResult> selector)
+        {
+            await foreach (var element in source)
+            {
+                yield return selector(element);
+            }
+        }
+
+        public async ValueTask<int> CountAsync(CancellationToken cancellationToken = default)
+        {
+            await using var e = source.GetAsyncEnumerator(cancellationToken);
+
+            var count = 0;
+            while (await e.MoveNextAsync())
+            {
+                checked
+                {
+                    count++;
+                }
+            }
+
+            return count;
+        }
+
+        public async IAsyncEnumerable<T> Take(int count)
+        {
+            await foreach (var element in source)
+            {
+                yield return element;
+
+                if (--count == 0)
+                {
+                    break;
+                }
+            }
+        }
+
         public async ValueTask<List<T>> ToListAsync()
         {
             var list = new List<T>();
@@ -42,16 +81,7 @@ public static class AsyncEnumerableExtensions
             return list;
         }
 
-        public async IAsyncEnumerable<TResult> Cast<TResult>()
-            where TResult : class
-        {
-            await foreach (var item in source)
-            {
-                yield return (item as TResult).NotNull();
-            }
-        }
-
-        public async ValueTask<bool> All(Func<T, bool> predicate)
+        public async ValueTask<bool> AllAsync(Func<T, bool> predicate)
         {
             await foreach (var item in source)
             {
@@ -75,27 +105,77 @@ public static class AsyncEnumerableExtensions
             }
         }
 
-        public async ValueTask<T?> FirstOrDefaultAsync()
+        public async ValueTask<T> SingleAsync(Func<T, bool>? predicate = null)
+        {
+            IAsyncEnumerator<T> enumerator;
+            if (predicate is null)
+            {
+                enumerator = source.GetAsyncEnumerator();
+            }
+            else
+            {
+                enumerator = source.Where(predicate).GetAsyncEnumerator();
+            }
+
+            if (!await enumerator.MoveNextAsync())
+            {
+                throw new InvalidOperationException("The source sequence is empty.");
+            }
+            var value = enumerator.Current;
+            if (await enumerator.MoveNextAsync())
+            {
+                throw new InvalidOperationException(
+                    "The source sequence contains more than one element."
+                );
+            }
+            return value;
+        }
+
+        public async ValueTask<T> FirstAsync()
         {
             await foreach (var item in source)
             {
-                return item; // Returns the very first item found
+                return item;
             }
-
-            return default; // Returns null/default if the stream is empty
+            throw new InvalidOperationException("The source sequence is empty.");
         }
 
-        public async ValueTask<TAccumulate> Aggregate<TAccumulate>(
-            TAccumulate seed,
-            Func<TAccumulate, T, TAccumulate> func
+        public async ValueTask<T?> FirstOrDefaultAsync(
+            CancellationToken cancellationToken = default
         )
         {
-            TAccumulate result = seed;
-            await foreach (var element in source)
+            await foreach (var item in source.WithCancellation(cancellationToken))
             {
-                result = func(result, element);
+                return item;
             }
-            return result;
+
+            return default;
         }
     }
+#endif
+
+    public static async IAsyncEnumerable<TResult> CastAsync<TResult>(
+        this IAsyncEnumerable<object?> source
+    )
+        where TResult : class
+    {
+        await foreach (var item in source)
+        {
+            yield return (item as TResult).NotNull();
+        }
+    }
+
+    public static async ValueTask<TAccumulate> AggregateAsync<TAccumulate, T>(
+        this IAsyncEnumerable<T> source,
+        TAccumulate seed,
+        Func<TAccumulate, T, TAccumulate> func
+    )
+    {
+        var result = seed;
+        await foreach (var element in source)
+        {
+            result = func(result, element);
+        }
+        return result;
+    }
 }