Mark for 0.39

Update to support net48, net481, netstandard2.0, net6 and net8

.config/dotnet-tools.json

@@ -3,10 +3,11 @@
   "isRoot": true,
   "tools": {
     "csharpier": {
-      "version": "0.27.3",
+      "version": "0.30.6",
       "commands": [
         "dotnet-csharpier"
-      ]
+      ],
+      "rollForward": false
     }
   }
 }

.editorconfig

@@ -70,7 +70,7 @@ indent_style = tab
 
 [*.{cs,csx,cake,vb,vbx}]
 # Default Severity for all .NET Code Style rules below
-dotnet_analyzer_diagnostic.severity = warning
+dotnet_analyzer_diagnostic.severity = silent
 
 ##########################################
 # File Header (Uncomment to support file headers)
@@ -269,6 +269,8 @@ dotnet_diagnostic.CA1305.severity = suggestion
 dotnet_diagnostic.CA1307.severity = suggestion
 dotnet_diagnostic.CA1309.severity = suggestion
 dotnet_diagnostic.CA1310.severity = error
+dotnet_diagnostic.CA1507.severity = suggestion
+dotnet_diagnostic.CA1513.severity = suggestion
 dotnet_diagnostic.CA1707.severity = suggestion
 dotnet_diagnostic.CA1708.severity = suggestion
 dotnet_diagnostic.CA1711.severity = suggestion
@@ -286,6 +288,7 @@ dotnet_diagnostic.CA1834.severity = error
 dotnet_diagnostic.CA1845.severity = suggestion
 dotnet_diagnostic.CA1848.severity = suggestion
 dotnet_diagnostic.CA1852.severity = suggestion
+dotnet_diagnostic.CA1860.severity = silent
 dotnet_diagnostic.CA2016.severity = suggestion
 dotnet_diagnostic.CA2201.severity = error
 dotnet_diagnostic.CA2206.severity = error
@@ -303,13 +306,12 @@ dotnet_diagnostic.CS1998.severity = error
 dotnet_diagnostic.CS8602.severity = error
 dotnet_diagnostic.CS8604.severity = error
 dotnet_diagnostic.CS8618.severity = error
-dotnet_diagnostic.CS0618.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
 dotnet_diagnostic.CS8625.severity = error
-dotnet_diagnostic.CS8981.severity = suggestion
 
 dotnet_diagnostic.BL0005.severity = suggestion
 
@@ -318,7 +320,7 @@ dotnet_diagnostic.MVC1000.severity = suggestion
 dotnet_diagnostic.RZ10012.severity = error
 
 dotnet_diagnostic.IDE0004.severity = error # redundant cast
-dotnet_diagnostic.IDE0005.severity = error
+dotnet_diagnostic.IDE0005.severity = suggestion
 dotnet_diagnostic.IDE0007.severity = error # Use var
 dotnet_diagnostic.IDE0011.severity = error # Use braces on if statements
 dotnet_diagnostic.IDE0010.severity = silent # populate switch
@@ -329,7 +331,7 @@ dotnet_diagnostic.IDE0023.severity = suggestion # use expression body for operat
 dotnet_diagnostic.IDE0024.severity = silent # expression body for operators
 dotnet_diagnostic.IDE0025.severity = suggestion # use expression body for properties
 dotnet_diagnostic.IDE0027.severity = suggestion # Use expression body for accessors
-dotnet_diagnostic.IDE0028.severity = silent
+dotnet_diagnostic.IDE0028.severity = silent # expression body for accessors
 dotnet_diagnostic.IDE0032.severity = suggestion # Use auto property
 dotnet_diagnostic.IDE0033.severity = error # prefer tuple name
 dotnet_diagnostic.IDE0037.severity = suggestion # simplify anonymous type
@@ -337,7 +339,7 @@ dotnet_diagnostic.IDE0040.severity = error # modifiers required
 dotnet_diagnostic.IDE0041.severity = error # simplify null
 dotnet_diagnostic.IDE0042.severity = error # deconstruct variable
 dotnet_diagnostic.IDE0044.severity = suggestion # make field only when possible
-dotnet_diagnostic.IDE0047.severity = suggestion # paratemeter name
+dotnet_diagnostic.IDE0047.severity = suggestion # parameter name
 dotnet_diagnostic.IDE0051.severity = error # unused field
 dotnet_diagnostic.IDE0052.severity = error # unused member
 dotnet_diagnostic.IDE0053.severity = suggestion # lambda not needed
@@ -351,11 +353,20 @@ dotnet_diagnostic.IDE0066.severity = suggestion # switch expression
 dotnet_diagnostic.IDE0072.severity = suggestion # Populate switch - forces population of all cases even when default specified
 dotnet_diagnostic.IDE0078.severity = suggestion # use pattern matching
 dotnet_diagnostic.IDE0090.severity = suggestion # new can be simplified
-dotnet_diagnostic.IDE0130.severity = error # namespace folder structure
+dotnet_diagnostic.IDE0130.severity = suggestion # namespace folder structure
 dotnet_diagnostic.IDE0160.severity = silent # Use block namespaces ARE NOT required
 dotnet_diagnostic.IDE0161.severity = error # Please use file namespaces
 dotnet_diagnostic.IDE0200.severity = suggestion # lambda not needed
 dotnet_diagnostic.IDE1006.severity = suggestion # Naming rule violation: These words cannot contain lower case characters
+dotnet_diagnostic.IDE0260.severity = suggestion # Use pattern matching
+dotnet_diagnostic.IDE0270.severity = suggestion # Null check simplifcation
+dotnet_diagnostic.IDE0290.severity = error # Primary Constructor
+dotnet_diagnostic.IDE0300.severity = suggestion # Collection
+dotnet_diagnostic.IDE0305.severity = suggestion # Collection ToList
+
+dotnet_diagnostic.NX0001.severity = error
+dotnet_diagnostic.NX0002.severity = silent
+dotnet_diagnostic.NX0003.severity = silent
 
 ##########################################
 # Styles

Directory.Build.props

@@ -10,5 +10,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <RunAnalyzersDuringLiveAnalysis>False</RunAnalyzersDuringLiveAnalysis>
     <RunAnalyzersDuringBuild>False</RunAnalyzersDuringBuild>
+    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+    <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 </Project>

Directory.Packages.props

@@ -0,0 +1,19 @@
+<Project>
+  <ItemGroup>
+    <PackageVersion Include="Bullseye" Version="5.0.0" />
+    <PackageVersion Include="FluentAssertions" Version="7.0.0" />
+    <PackageVersion Include="Glob" Version="1.1.9" />
+    <PackageVersion Include="Microsoft.Bcl.AsyncInterfaces" Version="8.0.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageVersion Include="Mono.Posix.NETStandard" Version="1.0.0" />
+    <PackageVersion Include="SimpleExec" Version="12.0.0" />
+    <PackageVersion Include="System.Buffers" Version="4.6.0" />
+    <PackageVersion Include="System.Memory" Version="4.6.0" />
+    <PackageVersion Include="System.Text.Encoding.CodePages" Version="8.0.0" />
+    <PackageVersion Include="xunit" Version="2.9.3" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="3.0.1" />
+    <PackageVersion Include="xunit.SkippableFact" Version="1.5.23" />
+    <PackageVersion Include="ZstdSharp.Port" Version="0.8.4" />
+    <GlobalPackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
+  </ItemGroup>
+</Project>

FORMATS.md

@@ -11,7 +11,7 @@
 | Archive Format         | Compression Format(s)                             | Compress/Decompress | Archive API     | Reader API | Writer API    |
 | ---------------------- | ------------------------------------------------- | ------------------- | --------------- | ---------- | ------------- |
 | Rar                    | Rar                                               | Decompress (1)      | RarArchive      | RarReader  | N/A           |
-| Zip (2)                | None, DEFLATE, Deflate64, BZip2, LZMA/LZMA2, PPMd | Both                | ZipArchive      | ZipReader  | ZipWriter     |
+| Zip (2)                | None, Shrink, Reduce, Implode, DEFLATE, Deflate64, BZip2, LZMA/LZMA2, PPMd                           | Both                | ZipArchive      | ZipReader  | ZipWriter     | 
 | Tar                    | None                                              | Both                | TarArchive      | TarReader  | TarWriter (3) |
 | Tar.GZip               | DEFLATE                                           | Both                | TarArchive      | TarReader  | TarWriter (3) |
 | Tar.BZip2              | BZip2                                             | Both                | TarArchive      | TarReader  | TarWriter (3) |

NuGet.config

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSourceMapping>
+    <!-- key value for <packageSource> should match key values from <packageSources> element -->
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
+</configuration>

README.md

@@ -1,12 +1,12 @@
 # SharpCompress
 
-SharpCompress is a compression library in pure C# for .NET Standard 2.0, 2.1, .NET Core 3.1 and .NET 5.0 that can unrar, un7zip, unzip, untar unbzip2, ungzip, unlzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip/lzip are implemented.
+SharpCompress is a compression library in pure C# for .NET Framework 4.62, .NET Standard 2.1, .NET 6.0 and NET 8.0 that can unrar, un7zip, unzip, untar unbzip2, ungzip, unlzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip/lzip are implemented.
 
 The major feature is support for non-seekable streams so large files can be processed on the fly (i.e. download stream).
 
 GitHub Actions Build -
 [![SharpCompress](https://github.com/adamhathcock/sharpcompress/actions/workflows/dotnetcore.yml/badge.svg)](https://github.com/adamhathcock/sharpcompress/actions/workflows/dotnetcore.yml)
-[![Static Badge](https://img.shields.io/badge/API%20Documentation-RobiniaDocs-43bc00?logo=readme&logoColor=white)](https://www.robiniadocs.com/d/sharpcompress/api/SharpCompress.html)
+[![Static Badge](https://img.shields.io/badge/API%20Docs-DNDocs-190088?logo=readme&logoColor=white)](https://dndocs.com/d/sharpcompress/api/index.html)
 
 ## Need Help?
 

SharpCompress.sln

@@ -17,6 +17,9 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Config", "Config", "{CDB425
 	ProjectSection(SolutionItems) = preProject
 		Directory.Build.props = Directory.Build.props
 		global.json = global.json
+		.editorconfig = .editorconfig
+		Directory.Packages.props = Directory.Packages.props
+		NuGet.config = NuGet.config
 	EndProjectSection
 EndProject
 Global

SharpCompress.sln.DotSettings

@@ -79,6 +79,10 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateStaticFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateStaticReadonly/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=StaticReadonly/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=15b5b1f1_002D457c_002D4ca6_002Db278_002D5615aedc07d3/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Private" Description="Static readonly fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;&lt;/Policy&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=4a98fdf6_002D7d98_002D4f5a_002Dafeb_002Dea44ad98c70c/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Instance" AccessRightKinds="Private" Description="Instance fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=c873eafb_002Dd57f_002D481d_002D8c93_002D77f6863c2f88/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Static readonly fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;&lt;/Policy&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=f9fce829_002De6f4_002D4cb2_002D80f1_002D5497c44f51df/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Private" Description="Static fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AA_BB" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/JavaScriptNaming/UserRules/=JS_005FBLOCK_005FSCOPE_005FCONSTANT/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/JavaScriptNaming/UserRules/=JS_005FBLOCK_005FSCOPE_005FFUNCTION/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/JavaScriptNaming/UserRules/=JS_005FBLOCK_005FSCOPE_005FVARIABLE/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
@@ -127,6 +131,7 @@
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002ECSharpPlaceAttributeOnSameLineMigration/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateBlankLinesAroundFieldToBlankLinesAroundProperty/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EMigrateThisQualifierSettings/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EPsi_002ECSharp_002ECodeStyle_002ESettingsUpgrade_002EPredefinedNamingRulesToUserRulesUpgrade/@EntryIndexedValue">True</s:Boolean>
 	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=6af8f80e_002D9fdd_002D4223_002D8e02_002D473db916f9b2/@EntryIndexedValue">&lt;SessionState ContinuousTestingIsOn="False" ContinuousTestingMode="0" FrameworkVersion="{x:Null}" IsLocked="False" Name="All tests from Solution" PlatformMonoPreference="{x:Null}" PlatformType="{x:Null}" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"&gt;
   &lt;Solution /&gt;
 &lt;/SessionState&gt;</s:String></wpf:ResourceDictionary>

USAGE.md

@@ -27,7 +27,7 @@ To deal with the "correct" rules as well as the expectations of users, I've deci
 
 To be explicit though, consider always using the overloads that use `ReaderOptions` or `WriterOptions` and explicitly set `LeaveStreamOpen` the way you want.
 
-If using Compression Stream classes directly and you don't want the wrapped stream to be closed.  Use the `NonDisposingStream` as a wrapped to prevent the stream being disposed.  The change in 0.21 simplified a lot even though the usage is a bit more convoluted.
+If using Compression Stream classes directly and you don't want the wrapped stream to be closed.  Use the `NonDisposingStream` as a wrapper to prevent the stream being disposed.  The change in 0.21 simplified a lot even though the usage is a bit more convoluted.
 
 ## Samples
 

build/build.csproj

@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Bullseye" Version="4.2.1" />
-    <PackageReference Include="Glob" Version="1.1.9" />
-    <PackageReference Include="SimpleExec" Version="11.0.0" />
+    <PackageReference Include="Bullseye" />
+    <PackageReference Include="Glob" />
+    <PackageReference Include="SimpleExec"  />
   </ItemGroup>
 
 </Project>

build/packages.lock.json

@@ -0,0 +1,45 @@
+{
+  "version": 2,
+  "dependencies": {
+    "net8.0": {
+      "Bullseye": {
+        "type": "Direct",
+        "requested": "[5.0.0, )",
+        "resolved": "5.0.0",
+        "contentHash": "bqyt+m17ym+5aN45C5oZRAjuLDt8jKiCm/ys1XfymIXSkrTFwvI/QsbY3ucPSHDz7SF7uON7B57kXFv5H2k1ew=="
+      },
+      "Glob": {
+        "type": "Direct",
+        "requested": "[1.1.9, )",
+        "resolved": "1.1.9",
+        "contentHash": "AfK5+ECWYTP7G3AAdnU8IfVj+QpGjrh9GC2mpdcJzCvtQ4pnerAGwHsxJ9D4/RnhDUz2DSzd951O/lQjQby2Sw=="
+      },
+      "Microsoft.SourceLink.GitHub": {
+        "type": "Direct",
+        "requested": "[8.0.0, )",
+        "resolved": "8.0.0",
+        "contentHash": "G5q7OqtwIyGTkeIOAc3u2ZuV/kicQaec5EaRnc0pIeSnh9LUjj+PYQrJYBURvDt7twGl2PKA7nSN0kz1Zw5bnQ==",
+        "dependencies": {
+          "Microsoft.Build.Tasks.Git": "8.0.0",
+          "Microsoft.SourceLink.Common": "8.0.0"
+        }
+      },
+      "SimpleExec": {
+        "type": "Direct",
+        "requested": "[12.0.0, )",
+        "resolved": "12.0.0",
+        "contentHash": "ptxlWtxC8vM6Y6e3h9ZTxBBkOWnWrm/Sa1HT+2i1xcXY3Hx2hmKDZP5RShPf8Xr9D+ivlrXNy57ktzyH8kyt+Q=="
+      },
+      "Microsoft.Build.Tasks.Git": {
+        "type": "Transitive",
+        "resolved": "8.0.0",
+        "contentHash": "bZKfSIKJRXLTuSzLudMFte/8CempWjVamNUR5eHJizsy+iuOuO/k2gnh7W0dHJmYY0tBf+gUErfluCv5mySAOQ=="
+      },
+      "Microsoft.SourceLink.Common": {
+        "type": "Transitive",
+        "resolved": "8.0.0",
+        "contentHash": "dk9JPxTCIevS75HyEQ0E4OVAFhB2N+V9ShCXf8Q6FkUQZDkgLI12y679Nym1YqsiSysuQskT7Z+6nUf3yab6Vw=="
+      }
+    }
+  }
+}

src/SharpCompress/Algorithms/Adler32.cs

@@ -141,7 +141,7 @@ internal static class Adler32 // From https://github.com/SixLabors/ImageSharp/bl
             4,
             3,
             2,
-            1 // tap2
+            1, // tap2
         };
 #endif
 

src/SharpCompress/Archives/AbstractArchive.cs

@@ -12,39 +12,35 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IArchiveExtra
     where TEntry : IArchiveEntry
     where TVolume : IVolume
 {
-    private readonly LazyReadOnlyCollection<TVolume> lazyVolumes;
-    private readonly LazyReadOnlyCollection<TEntry> lazyEntries;
+    private readonly LazyReadOnlyCollection<TVolume> _lazyVolumes;
+    private readonly LazyReadOnlyCollection<TEntry> _lazyEntries;
+    private bool _disposed;
+    private readonly SourceStream? _sourceStream;
 
     public event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>>? EntryExtractionBegin;
     public event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>>? EntryExtractionEnd;
 
     public event EventHandler<CompressedBytesReadEventArgs>? CompressedBytesRead;
     public event EventHandler<FilePartExtractionBeginEventArgs>? FilePartExtractionBegin;
-
     protected ReaderOptions ReaderOptions { get; }
 
-    private bool disposed;
-    protected SourceStream SrcStream;
-
-    internal AbstractArchive(ArchiveType type, SourceStream srcStream)
+    internal AbstractArchive(ArchiveType type, SourceStream sourceStream)
     {
         Type = type;
-        ReaderOptions = srcStream.ReaderOptions;
-        SrcStream = srcStream;
-        lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(SrcStream));
-        lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes));
+        ReaderOptions = sourceStream.ReaderOptions;
+        _sourceStream = sourceStream;
+        _lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(_sourceStream));
+        _lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes));
     }
 
-#nullable disable
     internal AbstractArchive(ArchiveType type)
     {
         Type = type;
-        lazyVolumes = new LazyReadOnlyCollection<TVolume>(Enumerable.Empty<TVolume>());
-        lazyEntries = new LazyReadOnlyCollection<TEntry>(Enumerable.Empty<TEntry>());
+        ReaderOptions = new();
+        _lazyVolumes = new LazyReadOnlyCollection<TVolume>(Enumerable.Empty<TVolume>());
+        _lazyEntries = new LazyReadOnlyCollection<TEntry>(Enumerable.Empty<TEntry>());
     }
 
-#nullable enable
-
     public ArchiveType Type { get; }
 
     void IArchiveExtractionListener.FireEntryExtractionBegin(IArchiveEntry entry) =>
@@ -65,12 +61,12 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IArchiveExtra
     /// <summary>
     /// Returns an ReadOnlyCollection of all the RarArchiveEntries across the one or many parts of the RarArchive.
     /// </summary>
-    public virtual ICollection<TEntry> Entries => lazyEntries;
+    public virtual ICollection<TEntry> Entries => _lazyEntries;
 
     /// <summary>
     /// Returns an ReadOnlyCollection of all the RarArchiveVolumes across the one or many parts of the RarArchive.
     /// </summary>
-    public ICollection<TVolume> Volumes => lazyVolumes;
+    public ICollection<TVolume> Volumes => _lazyVolumes;
 
     /// <summary>
     /// The total size of the files compressed in the archive.
@@ -84,29 +80,29 @@ public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IArchiveExtra
     public virtual long TotalUncompressSize =>
         Entries.Aggregate(0L, (total, cf) => total + cf.Size);
 
-    protected abstract IEnumerable<TVolume> LoadVolumes(SourceStream srcStream);
+    protected abstract IEnumerable<TVolume> LoadVolumes(SourceStream sourceStream);
     protected abstract IEnumerable<TEntry> LoadEntries(IEnumerable<TVolume> volumes);
 
     IEnumerable<IArchiveEntry> IArchive.Entries => Entries.Cast<IArchiveEntry>();
 
-    IEnumerable<IVolume> IArchive.Volumes => lazyVolumes.Cast<IVolume>();
+    IEnumerable<IVolume> IArchive.Volumes => _lazyVolumes.Cast<IVolume>();
 
     public virtual void Dispose()
     {
-        if (!disposed)
+        if (!_disposed)
         {
-            lazyVolumes.ForEach(v => v.Dispose());
-            lazyEntries.GetLoaded().Cast<Entry>().ForEach(x => x.Close());
-            SrcStream?.Dispose();
+            _lazyVolumes.ForEach(v => v.Dispose());
+            _lazyEntries.GetLoaded().Cast<Entry>().ForEach(x => x.Close());
+            _sourceStream?.Dispose();
 
-            disposed = true;
+            _disposed = true;
         }
     }
 
     void IArchiveExtractionListener.EnsureEntriesLoaded()
     {
-        lazyEntries.EnsureFullyLoaded();
-        lazyVolumes.EnsureFullyLoaded();
+        _lazyEntries.EnsureFullyLoaded();
+        _lazyVolumes.EnsureFullyLoaded();
     }
 
     void IExtractionListener.FireCompressedBytesRead(

src/SharpCompress/Archives/AbstractWritableArchive.cs

@@ -41,8 +41,8 @@ public abstract class AbstractWritableArchive<TEntry, TVolume>
     internal AbstractWritableArchive(ArchiveType type)
         : base(type) { }
 
-    internal AbstractWritableArchive(ArchiveType type, SourceStream srcStream)
-        : base(type, srcStream) { }
+    internal AbstractWritableArchive(ArchiveType type, SourceStream sourceStream)
+        : base(type, sourceStream) { }
 
     public override ICollection<TEntry> Entries
     {
@@ -120,6 +120,10 @@ public abstract class AbstractWritableArchive<TEntry, TVolume>
     {
         foreach (var path in Entries.Select(x => x.Key))
         {
+            if (path is null)
+            {
+                continue;
+            }
             var p = path.Replace('/', '\\');
             if (p.Length > 0 && p[0] == '\\')
             {

src/SharpCompress/Archives/ArchiveFactory.cs

@@ -189,9 +189,10 @@ public static class ArchiveFactory
 
         foreach (var factory in Factory.Factories)
         {
+            var isArchive = factory.IsArchive(stream);
             stream.Position = startPosition;
 
-            if (factory.IsArchive(stream, null))
+            if (isArchive)
             {
                 type = factory.KnownArchiveType;
                 return true;
@@ -239,4 +240,6 @@ public static class ArchiveFactory
             }
         }
     }
+
+    public static IArchiveFactory AutoFactory { get; } = new AutoArchiveFactory();
 }

src/SharpCompress/Archives/AutoArchiveFactory.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using SharpCompress.Common;
+using SharpCompress.Readers;
+
+namespace SharpCompress.Archives;
+
+class AutoArchiveFactory : IArchiveFactory
+{
+    public string Name => nameof(AutoArchiveFactory);
+
+    public ArchiveType? KnownArchiveType => null;
+
+    public IEnumerable<string> GetSupportedExtensions() => throw new NotSupportedException();
+
+    public bool IsArchive(Stream stream, string? password = null) =>
+        throw new NotSupportedException();
+
+    public FileInfo? GetFilePart(int index, FileInfo part1) => throw new NotSupportedException();
+
+    public IArchive Open(Stream stream, ReaderOptions? readerOptions = null) =>
+        ArchiveFactory.Open(stream, readerOptions);
+
+    public IArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null) =>
+        ArchiveFactory.Open(fileInfo, readerOptions);
+}

src/SharpCompress/Archives/GZip/GZipArchive.cs

@@ -90,7 +90,7 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
     {
         stream.CheckNotNull(nameof(stream));
         return new GZipArchive(
-            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
+            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
         );
     }
 
@@ -99,16 +99,14 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
     /// <summary>
     /// Constructor with a SourceStream able to handle FileInfo and Streams.
     /// </summary>
-    /// <param name="srcStream"></param>
-    /// <param name="options"></param>
-    internal GZipArchive(SourceStream srcStream)
-        : base(ArchiveType.Tar, srcStream) { }
+    /// <param name="sourceStream"></param>
+    private GZipArchive(SourceStream sourceStream)
+        : base(ArchiveType.GZip, sourceStream) { }
 
-    protected override IEnumerable<GZipVolume> LoadVolumes(SourceStream srcStream)
+    protected override IEnumerable<GZipVolume> LoadVolumes(SourceStream sourceStream)
     {
-        srcStream.LoadAllParts();
-        var idx = 0;
-        return srcStream.Streams.Select(a => new GZipVolume(a, ReaderOptions, idx++));
+        sourceStream.LoadAllParts();
+        return sourceStream.Streams.Select(a => new GZipVolume(a, ReaderOptions, 0));
     }
 
     public static bool IsGZipFile(string filePath) => IsGZipFile(new FileInfo(filePath));
@@ -184,7 +182,11 @@ public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
         foreach (var entry in oldEntries.Concat(newEntries).Where(x => !x.IsDirectory))
         {
             using var entryStream = entry.OpenEntryStream();
-            writer.Write(entry.Key, entryStream, entry.LastModifiedTime);
+            writer.Write(
+                entry.Key.NotNull("Entry Key is null"),
+                entryStream,
+                entry.LastModifiedTime
+            );
         }
     }
 

src/SharpCompress/Archives/GZip/GZipArchiveEntry.cs

@@ -6,7 +6,7 @@ namespace SharpCompress.Archives.GZip;
 
 public class GZipArchiveEntry : GZipEntry, IArchiveEntry
 {
-    internal GZipArchiveEntry(GZipArchive archive, GZipFilePart part)
+    internal GZipArchiveEntry(GZipArchive archive, GZipFilePart? part)
         : base(part) => Archive = archive;
 
     public virtual Stream OpenEntryStream()

src/SharpCompress/Archives/GZip/GZipWritableArchiveEntry.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -32,7 +30,7 @@ internal sealed class GZipWritableArchiveEntry : GZipArchiveEntry, IWritableArch
 
     public override long Crc => 0;
 
-    public override string Key { get; }
+    public override string? Key { get; }
 
     public override long CompressedSize => 0;
 

src/SharpCompress/Archives/IArchiveEntryExtensions.cs

@@ -17,15 +17,11 @@ public static class IArchiveEntryExtensions
         streamListener.EnsureEntriesLoaded();
         streamListener.FireEntryExtractionBegin(archiveEntry);
         streamListener.FireFilePartExtractionBegin(
-            archiveEntry.Key,
+            archiveEntry.Key ?? "Key",
             archiveEntry.Size,
             archiveEntry.CompressedSize
         );
         var entryStream = archiveEntry.OpenEntryStream();
-        if (entryStream is null)
-        {
-            return;
-        }
         using (entryStream)
         {
             using Stream s = new ListeningStream(streamListener, entryStream);

src/SharpCompress/Archives/IArchiveExtensions.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 
 namespace SharpCompress.Archives;
@@ -55,14 +54,26 @@ public static class IArchiveExtensions
             var entry = entries.Entry;
             if (entry.IsDirectory)
             {
+                var dirPath = Path.Combine(destination, entry.Key.NotNull("Entry Key is null"));
+                if (
+                    Path.GetDirectoryName(dirPath + "/") is { } emptyDirectory
+                    && seenDirectories.Add(dirPath)
+                )
+                {
+                    Directory.CreateDirectory(emptyDirectory);
+                }
                 continue;
             }
 
-            // Create each directory
-            var path = Path.Combine(destination, entry.Key);
-            if (Path.GetDirectoryName(path) is { } directory && seenDirectories.Add(path))
+            // Create each directory if not already created
+            var path = Path.Combine(destination, entry.Key.NotNull("Entry Key is null"));
+            if (Path.GetDirectoryName(path) is { } directory)
             {
-                Directory.CreateDirectory(directory);
+                if (!Directory.Exists(directory) && !seenDirectories.Contains(directory))
+                {
+                    Directory.CreateDirectory(directory);
+                    seenDirectories.Add(directory);
+                }
             }
 
             // Write file

src/SharpCompress/Archives/Rar/FileInfoRarArchiveVolume.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
 using SharpCompress.Common.Rar;
@@ -13,7 +14,7 @@ namespace SharpCompress.Archives.Rar;
 /// </summary>
 internal class FileInfoRarArchiveVolume : RarVolume
 {
-    internal FileInfoRarArchiveVolume(FileInfo fileInfo, ReaderOptions options, int index = 0)
+    internal FileInfoRarArchiveVolume(FileInfo fileInfo, ReaderOptions options, int index)
         : base(StreamingMode.Seekable, fileInfo.OpenRead(), FixOptions(options), index)
     {
         FileInfo = fileInfo;

src/SharpCompress/Archives/Rar/RarArchive.cs

@@ -14,6 +14,7 @@ namespace SharpCompress.Archives.Rar;
 
 public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
 {
+    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());
@@ -21,35 +22,47 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
     /// <summary>
     /// Constructor with a SourceStream able to handle FileInfo and Streams.
     /// </summary>
-    /// <param name="srcStream"></param>
-    /// <param name="options"></param>
-    internal RarArchive(SourceStream srcStream)
-        : base(ArchiveType.Rar, srcStream) { }
+    /// <param name="sourceStream"></param>
+    private RarArchive(SourceStream sourceStream)
+        : base(ArchiveType.Rar, sourceStream) { }
+
+    public override void Dispose()
+    {
+        if (!_disposed)
+        {
+            if (UnpackV1.IsValueCreated && UnpackV1.Value is IDisposable unpackV1)
+            {
+                unpackV1.Dispose();
+            }
+
+            _disposed = true;
+            base.Dispose();
+        }
+    }
 
     protected override IEnumerable<RarArchiveEntry> LoadEntries(IEnumerable<RarVolume> volumes) =>
         RarArchiveEntryFactory.GetEntries(this, volumes, ReaderOptions);
 
-    protected override IEnumerable<RarVolume> LoadVolumes(SourceStream srcStream)
+    protected override IEnumerable<RarVolume> LoadVolumes(SourceStream sourceStream)
     {
-        SrcStream.LoadAllParts(); //request all streams
-        var streams = SrcStream.Streams.ToArray();
-        var idx = 0;
+        sourceStream.LoadAllParts(); //request all streams
+        var streams = sourceStream.Streams.ToArray();
+        var i = 0;
         if (streams.Length > 1 && IsRarFile(streams[1], ReaderOptions)) //test part 2 - true = multipart not split
         {
-            SrcStream.IsVolumes = true;
+            sourceStream.IsVolumes = true;
             streams[1].Position = 0;
-            SrcStream.Position = 0;
+            sourceStream.Position = 0;
 
-            return srcStream.Streams.Select(a => new StreamRarArchiveVolume(
+            return sourceStream.Streams.Select(a => new StreamRarArchiveVolume(
                 a,
                 ReaderOptions,
-                idx++
+                i++
             ));
         }
-        else //split mode or single file
-        {
-            return new StreamRarArchiveVolume(SrcStream, ReaderOptions, idx++).AsEnumerable();
-        }
+
+        //split mode or single file
+        return new StreamRarArchiveVolume(sourceStream, ReaderOptions, i++).AsEnumerable();
     }
 
     protected override IReader CreateReaderForSolidExtraction()
@@ -108,7 +121,7 @@ public class RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
     public static RarArchive Open(Stream stream, ReaderOptions? options = null)
     {
         stream.CheckNotNull(nameof(stream));
-        return new RarArchive(new SourceStream(stream, i => null, options ?? new ReaderOptions()));
+        return new RarArchive(new SourceStream(stream, _ => null, options ?? new ReaderOptions()));
     }
 
     /// <summary>

src/SharpCompress/Archives/Rar/SeekableFilePart.cs

@@ -6,8 +6,8 @@ namespace SharpCompress.Archives.Rar;
 
 internal class SeekableFilePart : RarFilePart
 {
-    private readonly Stream stream;
-    private readonly string? password;
+    private readonly Stream _stream;
+    private readonly string? _password;
 
     internal SeekableFilePart(
         MarkHeader mh,
@@ -18,27 +18,27 @@ internal class SeekableFilePart : RarFilePart
     )
         : base(mh, fh, index)
     {
-        this.stream = stream;
-        this.password = password;
+        _stream = stream;
+        _password = password;
     }
 
     internal override Stream GetCompressedStream()
     {
-        stream.Position = FileHeader.DataStartPosition;
+        _stream.Position = FileHeader.DataStartPosition;
 
         if (FileHeader.R4Salt != null)
         {
-            var cryptKey = new CryptKey3(password!);
-            return new RarCryptoWrapper(stream, FileHeader.R4Salt, cryptKey);
+            var cryptKey = new CryptKey3(_password!);
+            return new RarCryptoWrapper(_stream, FileHeader.R4Salt, cryptKey);
         }
 
         if (FileHeader.Rar5CryptoInfo != null)
         {
-            var cryptKey = new CryptKey5(password!, FileHeader.Rar5CryptoInfo);
-            return new RarCryptoWrapper(stream, FileHeader.Rar5CryptoInfo.Salt, cryptKey);
+            var cryptKey = new CryptKey5(_password!, FileHeader.Rar5CryptoInfo);
+            return new RarCryptoWrapper(_stream, FileHeader.Rar5CryptoInfo.Salt, cryptKey);
         }
 
-        return stream;
+        return _stream;
     }
 
     internal override string FilePartName => "Unknown Stream - File Entry: " + FileHeader.FileName;

src/SharpCompress/Archives/Rar/StreamRarArchiveVolume.cs

@@ -9,7 +9,7 @@ namespace SharpCompress.Archives.Rar;
 
 internal class StreamRarArchiveVolume : RarVolume
 {
-    internal StreamRarArchiveVolume(Stream stream, ReaderOptions options, int index = 0)
+    internal StreamRarArchiveVolume(Stream stream, ReaderOptions options, int index)
         : base(StreamingMode.Seekable, stream, options, index) { }
 
     internal override IEnumerable<RarFilePart> ReadFileParts() => GetVolumeFileParts();

src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -14,14 +12,14 @@ namespace SharpCompress.Archives.SevenZip;
 
 public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVolume>
 {
-    private ArchiveDatabase database;
+    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)
+    public static SevenZipArchive Open(string filePath, ReaderOptions? readerOptions = null)
     {
         filePath.CheckNotNullOrEmpty("filePath");
         return Open(new FileInfo(filePath), readerOptions ?? new ReaderOptions());
@@ -32,7 +30,7 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     /// </summary>
     /// <param name="fileInfo"></param>
     /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(FileInfo fileInfo, ReaderOptions readerOptions = null)
+    public static SevenZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
     {
         fileInfo.CheckNotNull("fileInfo");
         return new SevenZipArchive(
@@ -51,7 +49,7 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     /// <param name="readerOptions"></param>
     public static SevenZipArchive Open(
         IEnumerable<FileInfo> fileInfos,
-        ReaderOptions readerOptions = null
+        ReaderOptions? readerOptions = null
     )
     {
         fileInfos.CheckNotNull(nameof(fileInfos));
@@ -72,7 +70,7 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     /// <param name="readerOptions"></param>
     public static SevenZipArchive Open(
         IEnumerable<Stream> streams,
-        ReaderOptions readerOptions = null
+        ReaderOptions? readerOptions = null
     )
     {
         streams.CheckNotNull(nameof(streams));
@@ -91,27 +89,25 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     /// </summary>
     /// <param name="stream"></param>
     /// <param name="readerOptions"></param>
-    public static SevenZipArchive Open(Stream stream, ReaderOptions readerOptions = null)
+    public static SevenZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
     {
         stream.CheckNotNull("stream");
         return new SevenZipArchive(
-            new SourceStream(stream, i => null, readerOptions ?? new ReaderOptions())
+            new SourceStream(stream, _ => null, readerOptions ?? new ReaderOptions())
         );
     }
 
     /// <summary>
     /// Constructor with a SourceStream able to handle FileInfo and Streams.
     /// </summary>
-    /// <param name="srcStream"></param>
-    /// <param name="options"></param>
-    internal SevenZipArchive(SourceStream srcStream)
-        : base(ArchiveType.SevenZip, srcStream) { }
+    /// <param name="sourceStream"></param>
+    private SevenZipArchive(SourceStream sourceStream)
+        : base(ArchiveType.SevenZip, sourceStream) { }
 
-    protected override IEnumerable<SevenZipVolume> LoadVolumes(SourceStream srcStream)
+    protected override IEnumerable<SevenZipVolume> LoadVolumes(SourceStream sourceStream)
     {
-        SrcStream.LoadAllParts(); //request all streams
-        var idx = 0;
-        return new SevenZipVolume(srcStream, ReaderOptions, idx++).AsEnumerable(); //simple single volume or split, multivolume not supported
+        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));
@@ -135,13 +131,17 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     {
         var stream = volumes.Single().Stream;
         LoadFactory(stream);
-        var entries = new SevenZipArchiveEntry[database._files.Count];
-        for (var i = 0; i < database._files.Count; i++)
+        if (_database is null)
         {
-            var file = database._files[i];
+            return Enumerable.Empty<SevenZipArchiveEntry>();
+        }
+        var entries = new SevenZipArchiveEntry[_database._files.Count];
+        for (var i = 0; i < _database._files.Count; i++)
+        {
+            var file = _database._files[i];
             entries[i] = new SevenZipArchiveEntry(
                 this,
-                new SevenZipFilePart(stream, database, i, file, ReaderOptions.ArchiveEncoding)
+                new SevenZipFilePart(stream, _database, i, file, ReaderOptions.ArchiveEncoding)
             );
         }
         foreach (var group in entries.Where(x => !x.IsDirectory).GroupBy(x => x.FilePart.Folder))
@@ -159,12 +159,12 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
 
     private void LoadFactory(Stream stream)
     {
-        if (database is null)
+        if (_database is null)
         {
             stream.Position = 0;
             var reader = new ArchiveReader();
-            reader.Open(stream);
-            database = reader.ReadDatabase(new PasswordProvider(ReaderOptions.Password));
+            reader.Open(stream, lookForHeader: ReaderOptions.LookForHeader);
+            _database = reader.ReadDatabase(new PasswordProvider(ReaderOptions.Password));
         }
     }
 
@@ -180,14 +180,14 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
         }
     }
 
-    private static ReadOnlySpan<byte> SIGNATURE =>
+    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);
+        return signatureBytes.SequenceEqual(Signature);
     }
 
     protected override IReader CreateReaderForSolidExtraction() =>
@@ -196,30 +196,24 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
     public override bool IsSolid =>
         Entries.Where(x => !x.IsDirectory).GroupBy(x => x.FilePart.Folder).Count() > 1;
 
-    public override long TotalSize
-    {
-        get
-        {
-            var i = Entries.Count;
-            return database._packSizes.Aggregate(0L, (total, packSize) => total + packSize);
-        }
-    }
+    public override long TotalSize =>
+        _database?._packSizes.Aggregate(0L, (total, packSize) => total + packSize) ?? 0;
 
     private sealed class SevenZipReader : AbstractReader<SevenZipEntry, SevenZipVolume>
     {
-        private readonly SevenZipArchive archive;
-        private CFolder currentFolder;
-        private Stream currentStream;
-        private CFileItem currentItem;
+        private readonly SevenZipArchive _archive;
+        private CFolder? _currentFolder;
+        private Stream? _currentStream;
+        private CFileItem? _currentItem;
 
         internal SevenZipReader(ReaderOptions readerOptions, SevenZipArchive archive)
-            : base(readerOptions, ArchiveType.SevenZip) => this.archive = archive;
+            : base(readerOptions, ArchiveType.SevenZip) => this._archive = archive;
 
-        public override SevenZipVolume Volume => archive.Volumes.Single();
+        public override SevenZipVolume Volume => _archive.Volumes.Single();
 
         protected override IEnumerable<SevenZipEntry> GetEntries(Stream stream)
         {
-            var entries = archive.Entries.ToList();
+            var entries = _archive.Entries.ToList();
             stream.Position = 0;
             foreach (var dir in entries.Where(x => x.IsDirectory))
             {
@@ -229,37 +223,42 @@ public class SevenZipArchive : AbstractArchive<SevenZipArchiveEntry, SevenZipVol
                 var group in entries.Where(x => !x.IsDirectory).GroupBy(x => x.FilePart.Folder)
             )
             {
-                currentFolder = group.Key;
+                _currentFolder = group.Key;
                 if (group.Key is null)
                 {
-                    currentStream = Stream.Null;
+                    _currentStream = Stream.Null;
                 }
                 else
                 {
-                    currentStream = archive.database.GetFolderStream(
+                    _currentStream = _archive._database?.GetFolderStream(
                         stream,
-                        currentFolder,
+                        _currentFolder,
                         new PasswordProvider(Options.Password)
                     );
                 }
                 foreach (var entry in group)
                 {
-                    currentItem = entry.FilePart.Header;
+                    _currentItem = entry.FilePart.Header;
                     yield return entry;
                 }
             }
         }
 
         protected override EntryStream GetEntryStream() =>
-            CreateEntryStream(new ReadOnlySubStream(currentStream, currentItem.Size));
+            CreateEntryStream(
+                new ReadOnlySubStream(
+                    _currentStream.NotNull("currentStream is not null"),
+                    _currentItem?.Size ?? 0
+                )
+            );
     }
 
     private class PasswordProvider : IPasswordProvider
     {
-        private readonly string _password;
+        private readonly string? _password;
 
-        public PasswordProvider(string password) => _password = password;
+        public PasswordProvider(string? password) => _password = password;
 
-        public string CryptoGetTextPassword() => _password;
+        public string? CryptoGetTextPassword() => _password;
     }
 }

src/SharpCompress/Archives/Tar/TarArchive.cs

@@ -114,7 +114,7 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
             var tarHeader = new TarHeader(new ArchiveEncoding());
             var readSucceeded = tarHeader.Read(new BinaryReader(stream));
             var isEmptyArchive =
-                tarHeader.Name.Length == 0
+                tarHeader.Name?.Length == 0
                 && tarHeader.Size == 0
                 && Enum.IsDefined(typeof(EntryType), tarHeader.EntryType);
             return readSucceeded || isEmptyArchive;
@@ -123,22 +123,20 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
         return false;
     }
 
-    protected override IEnumerable<TarVolume> LoadVolumes(SourceStream srcStream)
+    protected override IEnumerable<TarVolume> LoadVolumes(SourceStream sourceStream)
     {
-        SrcStream.LoadAllParts(); //request all streams
-        var idx = 0;
-        return new TarVolume(srcStream, ReaderOptions, idx++).AsEnumerable(); //simple single volume or split, multivolume not supported
+        sourceStream.NotNull("SourceStream is null").LoadAllParts(); //request all streams
+        return new TarVolume(sourceStream, ReaderOptions, 1).AsEnumerable(); //simple single volume or split, multivolume not supported
     }
 
     /// <summary>
     /// Constructor with a SourceStream able to handle FileInfo and Streams.
     /// </summary>
-    /// <param name="srcStream"></param>
-    /// <param name="options"></param>
-    internal TarArchive(SourceStream srcStream)
-        : base(ArchiveType.Tar, srcStream) { }
+    /// <param name="sourceStream"></param>
+    private TarArchive(SourceStream sourceStream)
+        : base(ArchiveType.Tar, sourceStream) { }
 
-    internal TarArchive()
+    private TarArchive()
         : base(ArchiveType.Tar) { }
 
     protected override IEnumerable<TarArchiveEntry> LoadEntries(IEnumerable<TarVolume> volumes)
@@ -192,6 +190,10 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
                     );
                 }
             }
+            else
+            {
+                throw new IncompleteArchiveException("Failed to read TAR header");
+            }
         }
     }
 
@@ -225,7 +227,12 @@ public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
         foreach (var entry in oldEntries.Concat(newEntries).Where(x => !x.IsDirectory))
         {
             using var entryStream = entry.OpenEntryStream();
-            writer.Write(entry.Key, entryStream, entry.LastModifiedTime, entry.Size);
+            writer.Write(
+                entry.Key.NotNull("Entry Key is null"),
+                entryStream,
+                entry.LastModifiedTime,
+                entry.Size
+            );
         }
     }
 

src/SharpCompress/Archives/Tar/TarArchiveEntry.cs

@@ -7,7 +7,7 @@ namespace SharpCompress.Archives.Tar;
 
 public class TarArchiveEntry : TarEntry, IArchiveEntry
 {
-    internal TarArchiveEntry(TarArchive archive, TarFilePart part, CompressionType compressionType)
+    internal TarArchiveEntry(TarArchive archive, TarFilePart? part, CompressionType compressionType)
         : base(part, compressionType) => Archive = archive;
 
     public virtual Stream OpenEntryStream() => Parts.Single().GetCompressedStream();

src/SharpCompress/Archives/Tar/TarWritableArchiveEntry.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;

src/SharpCompress/Archives/Zip/ZipArchive.cs

@@ -16,10 +16,7 @@ namespace SharpCompress.Archives.Zip;
 
 public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
 {
-#nullable disable
-    private readonly SeekableZipHeaderFactory headerFactory;
-
-#nullable enable
+    private readonly SeekableZipHeaderFactory? headerFactory;
 
     /// <summary>
     /// Gets or sets the compression level applied to files added to the archive,
@@ -30,13 +27,13 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
     /// <summary>
     /// Constructor with a SourceStream able to handle FileInfo and Streams.
     /// </summary>
-    /// <param name="srcStream"></param>
+    /// <param name="sourceStream"></param>
     /// <param name="options"></param>
-    internal ZipArchive(SourceStream srcStream)
-        : base(ArchiveType.Zip, srcStream) =>
+    internal ZipArchive(SourceStream sourceStream)
+        : base(ArchiveType.Zip, sourceStream) =>
         headerFactory = new SeekableZipHeaderFactory(
-            srcStream.ReaderOptions.Password,
-            srcStream.ReaderOptions.ArchiveEncoding
+            sourceStream.ReaderOptions.Password,
+            sourceStream.ReaderOptions.ArchiveEncoding
         );
 
     /// <summary>
@@ -189,21 +186,21 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
         }
     }
 
-    protected override IEnumerable<ZipVolume> LoadVolumes(SourceStream srcStream)
+    protected override IEnumerable<ZipVolume> LoadVolumes(SourceStream stream)
     {
-        SrcStream.LoadAllParts(); //request all streams
-        SrcStream.Position = 0;
+        stream.LoadAllParts(); //request all streams
+        stream.Position = 0;
 
-        var streams = SrcStream.Streams.ToList();
+        var streams = stream.Streams.ToList();
         var idx = 0;
-        if (streams.Count > 1) //test part 2 - true = multipart not split
+        if (streams.Count() > 1) //test part 2 - true = multipart not split
         {
             streams[1].Position += 4; //skip the POST_DATA_DESCRIPTOR to prevent an exception
             var isZip = IsZipFile(streams[1], ReaderOptions.Password);
             streams[1].Position -= 4;
             if (isZip)
             {
-                SrcStream.IsVolumes = true;
+                stream.IsVolumes = true;
 
                 var tmp = streams[0]; //arcs as zip, z01 ... swap the zip the end
                 streams.RemoveAt(0);
@@ -215,7 +212,7 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
         }
 
         //split mode or single file
-        return new ZipVolume(SrcStream, ReaderOptions, idx++).AsEnumerable();
+        return new ZipVolume(stream, ReaderOptions, idx++).AsEnumerable();
     }
 
     internal ZipArchive()
@@ -224,14 +221,13 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
     protected override IEnumerable<ZipArchiveEntry> LoadEntries(IEnumerable<ZipVolume> volumes)
     {
         var vols = volumes.ToArray();
-        foreach (var h in headerFactory.ReadSeekableHeader(vols.Last().Stream))
+        foreach (var h in headerFactory.NotNull().ReadSeekableHeader(vols.Last().Stream))
         {
             if (h != null)
             {
                 switch (h.ZipHeaderType)
                 {
                     case ZipHeaderType.DirectoryEntry:
-
                         {
                             var deh = (DirectoryEntryHeader)h;
                             Stream s;
@@ -254,14 +250,14 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
 
                             yield return new ZipArchiveEntry(
                                 this,
-                                new SeekableZipFilePart(headerFactory, deh, s)
+                                new SeekableZipFilePart(headerFactory.NotNull(), deh, s)
                             );
                         }
                         break;
                     case ZipHeaderType.DirectoryEnd:
                     {
                         var bytes = ((DirectoryEndHeader)h).Comment ?? Array.Empty<byte>();
-                        volumes.Last().Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
+                        vols.Last().Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
                         yield break;
                     }
                 }
@@ -282,7 +278,11 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
         foreach (var entry in oldEntries.Concat(newEntries).Where(x => !x.IsDirectory))
         {
             using var entryStream = entry.OpenEntryStream();
-            writer.Write(entry.Key, entryStream, entry.LastModifiedTime);
+            writer.Write(
+                entry.Key.NotNull("Entry Key is null"),
+                entryStream,
+                entry.LastModifiedTime
+            );
         }
     }
 

src/SharpCompress/AssemblyInfo.cs

@@ -1,3 +1,7 @@
 using System;
+using System.Runtime.CompilerServices;
 
 [assembly: CLSCompliant(true)]
+[assembly: InternalsVisibleTo(
+    "SharpCompress.Test,PublicKey=0024000004800000940000000602000000240000525341310004000001000100158bebf1433f76dffc356733c138babea7a47536c65ed8009b16372c6f4edbb20554db74a62687f56b97c20a6ce8c4b123280279e33c894e7b3aa93ab3c573656fde4db576cfe07dba09619ead26375b25d2c4a8e43f7be257d712b0dd2eb546f67adb09281338618a58ac834fc038dd7e2740a7ab3591826252e4f4516306dc"
+)]

src/SharpCompress/BufferPool.cs

@@ -1,33 +0,0 @@
-using System.Buffers;
-
-namespace SharpCompress;
-
-internal static class BufferPool
-{
-    /// <summary>
-    ///     gets a buffer from the pool
-    /// </summary>
-    /// <param name="bufferSize">size of the buffer</param>
-    /// <returns>the buffer</returns>
-    public static byte[] Rent(int bufferSize)
-    {
-#if NETCOREAPP || NETSTANDARD2_1_OR_GREATER
-        return ArrayPool<byte>.Shared.Rent(bufferSize);
-#else
-        return new byte[bufferSize];
-#endif
-    }
-
-    /// <summary>
-    ///     returns a buffer to the pool
-    /// </summary>
-    /// <param name="buffer">the buffer to return</param>
-    public static void Return(byte[] buffer)
-    {
-#if NETCOREAPP || NETSTANDARD2_1_OR_GREATER
-        ArrayPool<byte>.Shared.Return(buffer);
-#else
-        // no-op
-#endif
-    }
-}

src/SharpCompress/Common/ArchiveEncoding.cs

@@ -8,12 +8,12 @@ public class ArchiveEncoding
     /// <summary>
     /// Default encoding to use when archive format doesn't specify one.
     /// </summary>
-    public Encoding Default { get; set; }
+    public Encoding? Default { get; set; }
 
     /// <summary>
     /// ArchiveEncoding used by encryption schemes which don't comply with RFC 2898.
     /// </summary>
-    public Encoding Password { get; set; }
+    public Encoding? Password { get; set; }
 
     /// <summary>
     /// Set this encoding when you want to force it for all encoding operations.
@@ -50,6 +50,8 @@ public class ArchiveEncoding
 
     public Encoding GetEncoding() => Forced ?? Default ?? Encoding.UTF8;
 
+    public Encoding GetPasswordEncoding() => Password ?? Encoding.UTF8;
+
     public Func<byte[], int, int, string> GetDecoder() =>
         CustomDecoder ?? ((bytes, index, count) => GetEncoding().GetString(bytes, index, count));
 }

src/SharpCompress/Common/ArchiveType.cs

@@ -6,5 +6,5 @@ public enum ArchiveType
     Zip,
     Tar,
     SevenZip,
-    GZip
+    GZip,
 }

src/SharpCompress/Common/CompressionType.cs

@@ -16,5 +16,10 @@ public enum CompressionType
     Unknown,
     Deflate64,
     Shrink,
-    Lzw
+    Lzw,
+    Reduce1,
+    Reduce2,
+    Reduce3,
+    Reduce4,
+    Explode,
 }

src/SharpCompress/Common/Entry.cs

@@ -14,7 +14,7 @@ public abstract class Entry : IEntry
     /// <summary>
     /// The string key of the file internal to the Archive.
     /// </summary>
-    public abstract string Key { get; }
+    public abstract string? Key { get; }
 
     /// <summary>
     /// The target of a symlink entry internal to the Archive. Will be null if not a symlink.
@@ -71,11 +71,11 @@ public abstract class Entry : IEntry
     /// </summary>
     public abstract bool IsSplitAfter { get; }
 
-    public int VolumeIndexFirst => Parts?.FirstOrDefault()?.Index ?? 0;
-    public int VolumeIndexLast => Parts?.LastOrDefault()?.Index ?? 0;
+    public int VolumeIndexFirst => Parts.FirstOrDefault()?.Index ?? 0;
+    public int VolumeIndexLast => Parts.LastOrDefault()?.Index ?? 0;
 
     /// <inheritdoc/>
-    public override string ToString() => Key;
+    public override string ToString() => Key ?? "Entry";
 
     internal abstract IEnumerable<FilePart> Parts { get; }
 

src/SharpCompress/Common/ExtractionMethods.cs

@@ -36,10 +36,12 @@ internal static class ExtractionMethods
 
         options ??= new ExtractionOptions() { Overwrite = true };
 
-        var file = Path.GetFileName(entry.Key);
+        var file = Path.GetFileName(entry.Key.NotNull("Entry Key is null")).NotNull("File is null");
+        file = Utility.ReplaceInvalidFileNameChars(file);
         if (options.ExtractFullPath)
         {
-            var folder = Path.GetDirectoryName(entry.Key)!;
+            var folder = Path.GetDirectoryName(entry.Key.NotNull("Entry Key is null"))
+                .NotNull("Directory is null");
             var destdir = Path.GetFullPath(Path.Combine(fullDestinationDirectoryPath, folder));
 
             if (!Directory.Exists(destdir))

src/SharpCompress/Common/FilePart.cs

@@ -8,7 +8,7 @@ public abstract class FilePart
 
     internal ArchiveEncoding ArchiveEncoding { get; }
 
-    internal abstract string FilePartName { get; }
+    internal abstract string? FilePartName { get; }
     public int Index { get; set; }
 
     internal abstract Stream GetCompressedStream();

src/SharpCompress/Common/GZip/GZipEntry.cs

@@ -6,23 +6,23 @@ namespace SharpCompress.Common.GZip;
 
 public class GZipEntry : Entry
 {
-    private readonly GZipFilePart _filePart;
+    private readonly GZipFilePart? _filePart;
 
-    internal GZipEntry(GZipFilePart filePart) => _filePart = filePart;
+    internal GZipEntry(GZipFilePart? filePart) => _filePart = filePart;
 
     public override CompressionType CompressionType => CompressionType.GZip;
 
-    public override long Crc => _filePart.Crc ?? 0;
+    public override long Crc => _filePart?.Crc ?? 0;
 
-    public override string Key => _filePart.FilePartName;
+    public override string? Key => _filePart?.FilePartName;
 
     public override string? LinkTarget => null;
 
     public override long CompressedSize => 0;
 
-    public override long Size => _filePart.UncompressedSize ?? 0;
+    public override long Size => _filePart?.UncompressedSize ?? 0;
 
-    public override DateTime? LastModifiedTime => _filePart.DateModified;
+    public override DateTime? LastModifiedTime => _filePart?.DateModified;
 
     public override DateTime? CreatedTime => null;
 
@@ -36,7 +36,7 @@ public class GZipEntry : Entry
 
     public override bool IsSplitAfter => false;
 
-    internal override IEnumerable<FilePart> Parts => _filePart.AsEnumerable<FilePart>();
+    internal override IEnumerable<FilePart> Parts => _filePart.Empty();
 
     internal static IEnumerable<GZipEntry> GetEntries(Stream stream, OptionsBase options)
     {

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -34,7 +34,7 @@ internal sealed class GZipFilePart : FilePart
     internal uint? Crc { get; private set; }
     internal uint? UncompressedSize { get; private set; }
 
-    internal override string FilePartName => _name!;
+    internal override string? FilePartName => _name;
 
     internal override Stream GetCompressedStream() =>
         new DeflateStream(_stream, CompressionMode.Decompress, CompressionLevel.Default);

src/SharpCompress/Common/GZip/GZipVolume.cs

@@ -5,7 +5,7 @@ namespace SharpCompress.Common.GZip;
 
 public class GZipVolume : Volume
 {
-    public GZipVolume(Stream stream, ReaderOptions options, int index = 0)
+    public GZipVolume(Stream stream, ReaderOptions? options, int index)
         : base(stream, options, index) { }
 
     public GZipVolume(FileInfo fileInfo, ReaderOptions options)

src/SharpCompress/Common/IEntry.cs

@@ -9,7 +9,7 @@ public interface IEntry
     long CompressedSize { get; }
     long Crc { get; }
     DateTime? CreatedTime { get; }
-    string Key { get; }
+    string? Key { get; }
     string? LinkTarget { get; }
     bool IsDirectory { get; }
     bool IsEncrypted { get; }

src/SharpCompress/Common/IVolume.cs

@@ -6,5 +6,5 @@ public interface IVolume : IDisposable
 {
     int Index { get; }
 
-    string FileName { get; }
+    string? FileName { get; }
 }

src/SharpCompress/Common/Rar/Headers/FileHeader.cs

@@ -121,7 +121,6 @@ internal class FileHeader : RarHeader
             switch (type)
             {
                 case FHEXTRA_CRYPT: // file encryption
-
                     {
                         Rar5CryptoInfo = new Rar5CryptoInfo(reader, true);
 
@@ -132,7 +131,6 @@ internal class FileHeader : RarHeader
                     }
                     break;
                 case FHEXTRA_HASH:
-
                     {
                         const uint FHEXTRA_HASH_BLAKE2 = 0x0;
                         //                        const uint HASH_BLAKE2 = 0x03;
@@ -146,7 +144,6 @@ internal class FileHeader : RarHeader
                     }
                     break;
                 case FHEXTRA_HTIME: // file time
-
                     {
                         var flags = reader.ReadRarVIntUInt16();
                         var isWindowsTime = (flags & 1) == 0;
@@ -171,7 +168,6 @@ internal class FileHeader : RarHeader
                 //                        }
                 //                        break;
                 case FHEXTRA_REDIR: // file system redirection
-
                     {
                         RedirType = reader.ReadRarVIntByte();
                         RedirFlags = reader.ReadRarVIntByte();
@@ -284,7 +280,6 @@ internal class FileHeader : RarHeader
         switch (HeaderCode)
         {
             case HeaderCodeV.RAR4_FILE_HEADER:
-
                 {
                     if (HasFlag(FileFlagsV4.UNICODE))
                     {
@@ -311,7 +306,6 @@ internal class FileHeader : RarHeader
                 }
                 break;
             case HeaderCodeV.RAR4_NEW_SUB_HEADER:
-
                 {
                     var datasize = HeaderSize - newLhdSize - nameSize;
                     if (HasFlag(FileFlagsV4.SALT))

src/SharpCompress/Common/Rar/Headers/Flags.cs

@@ -13,7 +13,7 @@ public enum HeaderType : byte
     Sign,
     NewSub,
     EndArchive,
-    Crypt
+    Crypt,
 }
 
 internal static class HeaderCodeV

src/SharpCompress/Common/Rar/Headers/RarHeaderFactory.cs

@@ -98,13 +98,11 @@ public class RarHeaderFactory
                 switch (StreamingMode)
                 {
                     case StreamingMode.Seekable:
-
                         {
                             reader.BaseStream.Position += ph.DataSize;
                         }
                         break;
                     case StreamingMode.Streaming:
-
                         {
                             reader.BaseStream.Skip(ph.DataSize);
                         }
@@ -146,14 +144,12 @@ public class RarHeaderFactory
                 switch (StreamingMode)
                 {
                     case StreamingMode.Seekable:
-
                         {
                             fh.DataStartPosition = reader.BaseStream.Position;
                             reader.BaseStream.Position += fh.CompressedSize;
                         }
                         break;
                     case StreamingMode.Streaming:
-
                         {
                             var ms = new ReadOnlySubStream(reader.BaseStream, fh.CompressedSize);
                             if (fh.R4Salt is null && fh.Rar5CryptoInfo is null)
@@ -204,14 +200,12 @@ public class RarHeaderFactory
         switch (StreamingMode)
         {
             case StreamingMode.Seekable:
-
                 {
                     fh.DataStartPosition = reader.BaseStream.Position;
                     reader.BaseStream.Position += fh.CompressedSize;
                 }
                 break;
             case StreamingMode.Streaming:
-
                 {
                     //skip the data because it's useless?
                     reader.BaseStream.Skip(fh.CompressedSize);

src/SharpCompress/Common/Rar/RarCryptoWrapper.cs

@@ -70,11 +70,11 @@ internal sealed class RarCryptoWrapper : Stream
 
     protected override void Dispose(bool disposing)
     {
-        if (_rijndael != null)
+        if (disposing)
         {
             _rijndael.Dispose();
-            _rijndael = null!;
         }
+
         base.Dispose(disposing);
     }
 }

src/SharpCompress/Common/Rar/RarEntry.cs

@@ -25,7 +25,7 @@ public abstract class RarEntry : Entry
     /// <summary>
     /// The path of the file internal to the Rar Archive.
     /// </summary>
-    public override string Key => FileHeader.FileName;
+    public override string? Key => FileHeader.FileName;
 
     public override string? LinkTarget => null;
 

src/SharpCompress/Common/Rar/RarVolume.cs

@@ -15,17 +15,14 @@ namespace SharpCompress.Common.Rar;
 public abstract class RarVolume : Volume
 {
     private readonly RarHeaderFactory _headerFactory;
-    internal int _maxCompressionAlgorithm;
+    private int _maxCompressionAlgorithm;
 
-    internal RarVolume(StreamingMode mode, Stream stream, ReaderOptions options, int index = 0)
+    internal RarVolume(StreamingMode mode, Stream stream, ReaderOptions options, int index)
         : base(stream, options, index) => _headerFactory = new RarHeaderFactory(mode, options);
 
-#nullable disable
-    internal ArchiveHeader ArchiveHeader { get; private set; }
+    private ArchiveHeader? ArchiveHeader { get; set; }
 
-#nullable enable
-
-    internal StreamingMode Mode => _headerFactory.StreamingMode;
+    private StreamingMode Mode => _headerFactory.StreamingMode;
 
     internal abstract IEnumerable<RarFilePart> ReadFileParts();
 
@@ -39,19 +36,16 @@ public abstract class RarVolume : Volume
             switch (header.HeaderType)
             {
                 case HeaderType.Mark:
-
                     {
                         lastMarkHeader = (MarkHeader)header;
                     }
                     break;
                 case HeaderType.Archive:
-
                     {
                         ArchiveHeader = (ArchiveHeader)header;
                     }
                     break;
                 case HeaderType.File:
-
                     {
                         var fh = (FileHeader)header;
                         if (_maxCompressionAlgorithm < fh.CompressionAlgorithm)
@@ -63,14 +57,12 @@ public abstract class RarVolume : Volume
                     }
                     break;
                 case HeaderType.Service:
-
                     {
                         var fh = (FileHeader)header;
                         if (fh.FileName == "CMT")
                         {
-                            var part = CreateFilePart(lastMarkHeader!, fh);
                             var buffer = new byte[fh.CompressedSize];
-                            part.GetCompressedStream().Read(buffer, 0, buffer.Length);
+                            fh.PackedStream.Read(buffer, 0, buffer.Length);
                             Comment = Encoding.UTF8.GetString(buffer, 0, buffer.Length - 1);
                         }
                     }
@@ -105,7 +97,7 @@ public abstract class RarVolume : Volume
         get
         {
             EnsureArchiveHeaderLoaded();
-            return ArchiveHeader.IsFirstVolume;
+            return ArchiveHeader?.IsFirstVolume ?? false;
         }
     }
 
@@ -117,7 +109,7 @@ public abstract class RarVolume : Volume
         get
         {
             EnsureArchiveHeaderLoaded();
-            return ArchiveHeader.IsVolume;
+            return ArchiveHeader?.IsVolume ?? false;
         }
     }
 
@@ -130,7 +122,7 @@ public abstract class RarVolume : Volume
         get
         {
             EnsureArchiveHeaderLoaded();
-            return ArchiveHeader.IsSolid;
+            return ArchiveHeader?.IsSolid ?? false;
         }
     }
 

src/SharpCompress/Common/SevenZip/ArchiveDatabase.cs

@@ -35,7 +35,7 @@ internal class ArchiveDatabase
         _packSizes.Clear();
         _packCrCs.Clear();
         _folders.Clear();
-        _numUnpackStreamsVector = null!;
+        _numUnpackStreamsVector = null;
         _files.Clear();
 
         _packStreamStartPositions.Clear();

src/SharpCompress/Common/SevenZip/ArchiveReader.cs

@@ -1220,23 +1220,46 @@ internal class ArchiveReader
 
     #region Public Methods
 
-    public void Open(Stream stream)
+    public void Open(Stream stream, bool lookForHeader)
     {
         Close();
 
         _streamOrigin = stream.Position;
         _streamEnding = stream.Length;
 
-        // TODO: Check Signature!
-        _header = new byte[0x20];
-        for (var offset = 0; offset < 0x20; )
+        var canScan = lookForHeader ? 0x80000 - 20 : 0;
+        while (true)
         {
-            var delta = stream.Read(_header, offset, 0x20 - offset);
-            if (delta == 0)
+            // TODO: Check Signature!
+            _header = new byte[0x20];
+            for (var offset = 0; offset < 0x20; )
             {
-                throw new EndOfStreamException();
+                var delta = stream.Read(_header, offset, 0x20 - offset);
+                if (delta == 0)
+                {
+                    throw new EndOfStreamException();
+                }
+
+                offset += delta;
             }
-            offset += delta;
+
+            if (
+                !lookForHeader
+                || _header
+                    .AsSpan(0, length: 6)
+                    .SequenceEqual<byte>([0x37, 0x7A, 0xBC, 0xAF, 0x27, 0x1C])
+            )
+            {
+                break;
+            }
+
+            if (canScan == 0)
+            {
+                throw new InvalidFormatException("Unable to find 7z signature");
+            }
+
+            canScan--;
+            stream.Position = ++_streamOrigin;
         }
 
         _stream = stream;

src/SharpCompress/Common/SevenZip/SevenZipEntry.cs

@@ -13,7 +13,7 @@ public class SevenZipEntry : Entry
 
     public override long Crc => FilePart.Header.Crc ?? 0;
 
-    public override string Key => FilePart.Header.Name;
+    public override string? Key => FilePart.Header.Name;
 
     public override string? LinkTarget => null;
 

src/SharpCompress/Common/SevenZip/SevenZipFilePart.cs

@@ -41,7 +41,7 @@ internal class SevenZipFilePart : FilePart
     {
         if (!Header.HasStream)
         {
-            return null!;
+            throw new InvalidOperationException("File does not have a stream.");
         }
         var folderStream = _database.GetFolderStream(_stream, Folder!, _database.PasswordProvider);
 
@@ -73,34 +73,24 @@ internal class SevenZipFilePart : FilePart
     private const uint K_PPMD = 0x030401;
     private const uint K_B_ZIP2 = 0x040202;
 
-    internal CompressionType GetCompression()
+    private CompressionType GetCompression()
     {
         if (Header.IsDir)
-            return CompressionType.None;
-
-        var coder = Folder!._coders.First();
-        switch (coder._methodId._id)
         {
-            case K_LZMA:
-            case K_LZMA2:
-            {
-                return CompressionType.LZMA;
-            }
-            case K_PPMD:
-            {
-                return CompressionType.PPMd;
-            }
-            case K_B_ZIP2:
-            {
-                return CompressionType.BZip2;
-            }
-            default:
-                throw new NotImplementedException();
+            return CompressionType.None;
         }
+
+        var coder = Folder.NotNull()._coders.First();
+        return coder._methodId._id switch
+        {
+            K_LZMA or K_LZMA2 => CompressionType.LZMA,
+            K_PPMD => CompressionType.PPMd,
+            K_B_ZIP2 => CompressionType.BZip2,
+            _ => throw new NotImplementedException(),
+        };
     }
 
     internal bool IsEncrypted =>
-        Header.IsDir
-            ? false
-            : Folder!._coders.FindIndex(c => c._methodId._id == CMethodId.K_AES_ID) != -1;
+        !Header.IsDir
+        && Folder?._coders.FindIndex(c => c._methodId._id == CMethodId.K_AES_ID) != -1;
 }

src/SharpCompress/Common/Tar/Headers/EntryType.cs

@@ -14,5 +14,5 @@ internal enum EntryType : byte
     LongName = (byte)'L',
     SparseFile = (byte)'S',
     VolumeHeader = (byte)'V',
-    GlobalExtendedHeader = (byte)'g'
+    GlobalExtendedHeader = (byte)'g',
 }

src/SharpCompress/Common/Tar/Headers/TarHeader.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Buffers.Binary;
 using System.IO;
@@ -13,8 +11,8 @@ internal sealed class TarHeader
 
     public TarHeader(ArchiveEncoding archiveEncoding) => ArchiveEncoding = archiveEncoding;
 
-    internal string Name { get; set; }
-    internal string LinkName { get; set; }
+    internal string? Name { get; set; }
+    internal string? LinkName { get; set; }
 
     internal long Mode { get; set; }
     internal long UserId { get; set; }
@@ -22,7 +20,7 @@ internal sealed class TarHeader
     internal long Size { get; set; }
     internal DateTime LastModifiedTime { get; set; }
     internal EntryType EntryType { get; set; }
-    internal Stream PackedStream { get; set; }
+    internal Stream? PackedStream { get; set; }
     internal ArchiveEncoding ArchiveEncoding { get; }
 
     internal const int BLOCK_SIZE = 512;
@@ -36,7 +34,9 @@ internal sealed class TarHeader
         WriteOctalBytes(0, buffer, 116, 8); // group ID
 
         //ArchiveEncoding.UTF8.GetBytes("magic").CopyTo(buffer, 257);
-        var nameByteCount = ArchiveEncoding.GetEncoding().GetByteCount(Name);
+        var nameByteCount = ArchiveEncoding
+            .GetEncoding()
+            .GetByteCount(Name.NotNull("Name is null"));
         if (nameByteCount > 100)
         {
             // Set mock filename and filetype to indicate the next block is the actual name of the file
@@ -46,7 +46,7 @@ internal sealed class TarHeader
         }
         else
         {
-            WriteStringBytes(ArchiveEncoding.Encode(Name), buffer, 100);
+            WriteStringBytes(ArchiveEncoding.Encode(Name.NotNull("Name is null")), buffer, 100);
             WriteOctalBytes(Size, buffer, 124, 12);
             var time = (long)(LastModifiedTime.ToUniversalTime() - EPOCH).TotalSeconds;
             WriteOctalBytes(time, buffer, 136, 12);
@@ -77,7 +77,7 @@ internal sealed class TarHeader
             //
             // and then infinite recursion is occured in WriteLongFilenameHeader because truncated.Length is 102.
             Name = ArchiveEncoding.Decode(
-                ArchiveEncoding.Encode(Name),
+                ArchiveEncoding.Encode(Name.NotNull("Name is null")),
                 0,
                 100 - ArchiveEncoding.GetEncoding().GetMaxByteCount(1)
             );
@@ -87,7 +87,7 @@ internal sealed class TarHeader
 
     private void WriteLongFilenameHeader(Stream output)
     {
-        var nameBytes = ArchiveEncoding.Encode(Name);
+        var nameBytes = ArchiveEncoding.Encode(Name.NotNull("Name is null"));
         output.Write(nameBytes, 0, nameBytes.Length);
 
         // pad to multiple of BlockSize bytes, and make sure a terminating null is added
@@ -101,57 +101,85 @@ internal sealed class TarHeader
 
     internal bool Read(BinaryReader reader)
     {
-        var buffer = ReadBlock(reader);
-        if (buffer.Length == 0)
+        string? longName = null;
+        string? longLinkName = null;
+        var hasLongValue = true;
+        byte[] buffer;
+        EntryType entryType;
+
+        do
+        {
+            buffer = ReadBlock(reader);
+
+            if (buffer.Length == 0)
+            {
+                return false;
+            }
+
+            entryType = ReadEntryType(buffer);
+
+            // LongName and LongLink headers can follow each other and need
+            // to apply to the header that follows them.
+            if (entryType == EntryType.LongName)
+            {
+                longName = ReadLongName(reader, buffer);
+                continue;
+            }
+            else if (entryType == EntryType.LongLink)
+            {
+                longLinkName = ReadLongName(reader, buffer);
+                continue;
+            }
+
+            hasLongValue = false;
+        } while (hasLongValue);
+
+        // Check header checksum
+        if (!checkChecksum(buffer))
         {
             return false;
         }
 
-        // for symlinks, additionally read the linkname
-        if (ReadEntryType(buffer) == EntryType.SymLink)
-        {
-            LinkName = ArchiveEncoding.Decode(buffer, 157, 100).TrimNulls();
-        }
-
-        if (ReadEntryType(buffer) == EntryType.LongName)
-        {
-            Name = ReadLongName(reader, buffer);
-            buffer = ReadBlock(reader);
-        }
-        else
-        {
-            Name = ArchiveEncoding.Decode(buffer, 0, 100).TrimNulls();
-        }
-
-        EntryType = ReadEntryType(buffer);
+        Name = longName ?? ArchiveEncoding.Decode(buffer, 0, 100).TrimNulls();
+        EntryType = entryType;
         Size = ReadSize(buffer);
 
+        // for symlinks, additionally read the linkname
+        if (entryType == EntryType.SymLink || entryType == EntryType.HardLink)
+        {
+            LinkName = longLinkName ?? ArchiveEncoding.Decode(buffer, 157, 100).TrimNulls();
+        }
+
         Mode = ReadAsciiInt64Base8(buffer, 100, 7);
-        if (EntryType == EntryType.Directory)
+
+        if (entryType == EntryType.Directory)
         {
             Mode |= 0b1_000_000_000;
         }
 
         UserId = ReadAsciiInt64Base8oldGnu(buffer, 108, 7);
         GroupId = ReadAsciiInt64Base8oldGnu(buffer, 116, 7);
-        var unixTimeStamp = ReadAsciiInt64Base8(buffer, 136, 11);
-        LastModifiedTime = EPOCH.AddSeconds(unixTimeStamp).ToLocalTime();
 
+        var unixTimeStamp = ReadAsciiInt64Base8(buffer, 136, 11);
+
+        LastModifiedTime = EPOCH.AddSeconds(unixTimeStamp).ToLocalTime();
         Magic = ArchiveEncoding.Decode(buffer, 257, 6).TrimNulls();
 
         if (!string.IsNullOrEmpty(Magic) && "ustar".Equals(Magic))
         {
-            var namePrefix = ArchiveEncoding.Decode(buffer, 345, 157);
-            namePrefix = namePrefix.TrimNulls();
+            var namePrefix = ArchiveEncoding.Decode(buffer, 345, 157).TrimNulls();
+
             if (!string.IsNullOrEmpty(namePrefix))
             {
                 Name = namePrefix + "/" + Name;
             }
         }
-        if (EntryType != EntryType.LongName && Name.Length == 0)
+
+        if (entryType != EntryType.LongName && Name.Length == 0)
         {
             return false;
         }
+
         return true;
     }
 
@@ -286,9 +314,45 @@ internal sealed class TarHeader
         (byte)' ',
         (byte)' ',
         (byte)' ',
-        (byte)' '
+        (byte)' ',
     };
 
+    internal static bool checkChecksum(byte[] buf)
+    {
+        const int eightSpacesChksum = 256;
+        var buffer = new Span<byte>(buf).Slice(0, 512);
+        int posix_sum = eightSpacesChksum;
+        int sun_sum = eightSpacesChksum;
+
+        foreach (byte b in buffer)
+        {
+            posix_sum += b;
+            sun_sum += unchecked((sbyte)b);
+        }
+
+        // Special case, empty file header
+        if (posix_sum == eightSpacesChksum)
+        {
+            return true;
+        }
+
+        // Remove current checksum from calculation
+        foreach (byte b in buffer.Slice(148, 8))
+        {
+            posix_sum -= b;
+            sun_sum -= unchecked((sbyte)b);
+        }
+
+        // Read and compare checksum for header
+        var crc = ReadAsciiInt64Base8(buf, 148, 7);
+        if (crc != posix_sum && crc != sun_sum)
+        {
+            return false;
+        }
+
+        return true;
+    }
+
     internal static int RecalculateChecksum(byte[] buf)
     {
         // Set default value for checksum. That is 8 spaces.
@@ -323,5 +387,5 @@ internal sealed class TarHeader
 
     public long? DataStartPosition { get; set; }
 
-    public string Magic { get; set; }
+    public string? Magic { get; set; }
 }

src/SharpCompress/Common/Tar/TarEntry.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -10,9 +8,9 @@ namespace SharpCompress.Common.Tar;
 
 public class TarEntry : Entry
 {
-    private readonly TarFilePart _filePart;
+    private readonly TarFilePart? _filePart;
 
-    internal TarEntry(TarFilePart filePart, CompressionType type)
+    internal TarEntry(TarFilePart? filePart, CompressionType type)
     {
         _filePart = filePart;
         CompressionType = type;
@@ -22,15 +20,15 @@ public class TarEntry : Entry
 
     public override long Crc => 0;
 
-    public override string Key => _filePart.Header.Name;
+    public override string? Key => _filePart?.Header.Name;
 
-    public override string LinkTarget => _filePart.Header.LinkName;
+    public override string? LinkTarget => _filePart?.Header.LinkName;
 
-    public override long CompressedSize => _filePart.Header.Size;
+    public override long CompressedSize => _filePart?.Header.Size ?? 0;
 
-    public override long Size => _filePart.Header.Size;
+    public override long Size => _filePart?.Header.Size ?? 0;
 
-    public override DateTime? LastModifiedTime => _filePart.Header.LastModifiedTime;
+    public override DateTime? LastModifiedTime => _filePart?.Header.LastModifiedTime;
 
     public override DateTime? CreatedTime => null;
 
@@ -40,17 +38,17 @@ public class TarEntry : Entry
 
     public override bool IsEncrypted => false;
 
-    public override bool IsDirectory => _filePart.Header.EntryType == EntryType.Directory;
+    public override bool IsDirectory => _filePart?.Header.EntryType == EntryType.Directory;
 
     public override bool IsSplitAfter => false;
 
-    public long Mode => _filePart.Header.Mode;
+    public long Mode => _filePart?.Header.Mode ?? 0;
 
-    public long UserID => _filePart.Header.UserId;
+    public long UserID => _filePart?.Header.UserId ?? 0;
 
-    public long GroupId => _filePart.Header.GroupId;
+    public long GroupId => _filePart?.Header.GroupId ?? 0;
 
-    internal override IEnumerable<FilePart> Parts => _filePart.AsEnumerable<FilePart>();
+    internal override IEnumerable<FilePart> Parts => _filePart.Empty();
 
     internal static IEnumerable<TarEntry> GetEntries(
         StreamingMode mode,
@@ -59,17 +57,17 @@ public class TarEntry : Entry
         ArchiveEncoding archiveEncoding
     )
     {
-        foreach (var h in TarHeaderFactory.ReadHeader(mode, stream, archiveEncoding))
+        foreach (var header in TarHeaderFactory.ReadHeader(mode, stream, archiveEncoding))
         {
-            if (h != null)
+            if (header != null)
             {
                 if (mode == StreamingMode.Seekable)
                 {
-                    yield return new TarEntry(new TarFilePart(h, stream), compressionType);
+                    yield return new TarEntry(new TarFilePart(header, stream), compressionType);
                 }
                 else
                 {
-                    yield return new TarEntry(new TarFilePart(h, null), compressionType);
+                    yield return new TarEntry(new TarFilePart(header, null), compressionType);
                 }
             }
             else

src/SharpCompress/Common/Tar/TarFilePart.cs

@@ -5,9 +5,9 @@ namespace SharpCompress.Common.Tar;
 
 internal sealed class TarFilePart : FilePart
 {
-    private readonly Stream _seekableStream;
+    private readonly Stream? _seekableStream;
 
-    internal TarFilePart(TarHeader header, Stream seekableStream)
+    internal TarFilePart(TarHeader header, Stream? seekableStream)
         : base(header.ArchiveEncoding)
     {
         _seekableStream = seekableStream;
@@ -16,16 +16,16 @@ internal sealed class TarFilePart : FilePart
 
     internal TarHeader Header { get; }
 
-    internal override string FilePartName => Header.Name;
+    internal override string? FilePartName => Header?.Name;
 
     internal override Stream GetCompressedStream()
     {
         if (_seekableStream != null)
         {
-            _seekableStream.Position = Header.DataStartPosition!.Value;
+            _seekableStream.Position = Header.DataStartPosition ?? 0;
             return new TarReadOnlySubStream(_seekableStream, Header.Size);
         }
-        return Header.PackedStream;
+        return Header.PackedStream.NotNull();
     }
 
     internal override Stream? GetRawStream() => null;

src/SharpCompress/Common/Tar/TarHeaderFactory.cs

@@ -28,7 +28,6 @@ internal static class TarHeaderFactory
                 switch (mode)
                 {
                     case StreamingMode.Seekable:
-
                         {
                             header.DataStartPosition = reader.BaseStream.Position;
 
@@ -37,7 +36,6 @@ internal static class TarHeaderFactory
                         }
                         break;
                     case StreamingMode.Streaming:
-
                         {
                             header.PackedStream = new TarReadOnlySubStream(stream, header.Size);
                         }

src/SharpCompress/Common/Volume.cs

@@ -9,11 +9,11 @@ public abstract class Volume : IVolume
 {
     private readonly Stream _actualStream;
 
-    internal Volume(Stream stream, ReaderOptions readerOptions, int index = 0)
+    internal Volume(Stream stream, ReaderOptions? readerOptions, int index = 0)
     {
         Index = index;
-        ReaderOptions = readerOptions;
-        if (readerOptions.LeaveStreamOpen)
+        ReaderOptions = readerOptions ?? new ReaderOptions();
+        if (ReaderOptions.LeaveStreamOpen)
         {
             stream = NonDisposingStream.Create(stream);
         }
@@ -32,7 +32,7 @@ public abstract class Volume : IVolume
 
     public virtual int Index { get; internal set; }
 
-    public string FileName => (_actualStream as FileStream)?.Name!;
+    public string? FileName => (_actualStream as FileStream)?.Name;
 
     /// <summary>
     /// RarArchive is part of a multi-part archive.

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

@@ -13,5 +13,5 @@ internal enum HeaderFlags : ushort
     EnhancedDeflate = 16,
 
     //Bit 11: Language encoding flag
-    Efs = 2048
+    Efs = 2048,
 }

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

@@ -14,7 +14,7 @@ internal enum ExtraDataType : ushort
     // -Info-ZIP Unicode Path Extra Field
     UnicodePathExtraField = 0x7075,
     Zip64ExtendedInformationExtraField = 0x0001,
-    UnixTimeExtraField = 0x5455
+    UnixTimeExtraField = 0x5455,
 }
 
 internal class ExtraData
@@ -166,10 +166,10 @@ internal sealed class UnixTimeExtraField : ExtraData
                 return Tuple.Create<DateTime?, DateTime?, DateTime?>(null, null, null);
             }
 
-            var flags = DataBytes[0];
-            var isModifiedTimeSpecified = (flags & 0x01) == 1;
-            var isLastAccessTimeSpecified = (flags & 0x02) == 1;
-            var isCreationTimeSpecified = (flags & 0x04) == 1;
+            var flags = (RecordedTimeFlag)DataBytes[0];
+            var isModifiedTimeSpecified = flags.HasFlag(RecordedTimeFlag.LastModified);
+            var isLastAccessTimeSpecified = flags.HasFlag(RecordedTimeFlag.LastAccessed);
+            var isCreationTimeSpecified = flags.HasFlag(RecordedTimeFlag.Created);
             var currentIndex = 1;
             DateTime? modifiedTime = null;
             DateTime? lastAccessTime = null;
@@ -189,7 +189,7 @@ internal sealed class UnixTimeExtraField : ExtraData
             {
                 if (currentIndex + 4 > DataBytes.Length)
                 {
-                    throw new ArchiveException("Invalid UnicodeExtraTime field");
+                    return Tuple.Create<DateTime?, DateTime?, DateTime?>(null, null, null);
                 }
 
                 var lastAccessEpochTime = BinaryPrimitives.ReadInt32LittleEndian(
@@ -206,7 +206,7 @@ internal sealed class UnixTimeExtraField : ExtraData
             {
                 if (currentIndex + 4 > DataBytes.Length)
                 {
-                    throw new ArchiveException("Invalid UnicodeExtraTime field");
+                    return Tuple.Create<DateTime?, DateTime?, DateTime?>(null, null, null);
                 }
 
                 var creationTimeEpochTime = BinaryPrimitives.ReadInt32LittleEndian(
@@ -222,6 +222,15 @@ internal sealed class UnixTimeExtraField : ExtraData
             return Tuple.Create(modifiedTime, lastAccessTime, creationTime);
         }
     }
+
+    [Flags]
+    private enum RecordedTimeFlag
+    {
+        None = 0,
+        LastModified = 1,
+        LastAccessed = 2,
+        Created = 4,
+    }
 }
 
 internal static class LocalEntryHeaderExtraFactory
@@ -229,11 +238,14 @@ internal static class LocalEntryHeaderExtraFactory
     internal static ExtraData Create(ExtraDataType type, ushort length, byte[] extraData) =>
         type switch
         {
-            ExtraDataType.UnicodePathExtraField
-                => new ExtraUnicodePathExtraField(type, length, extraData),
-            ExtraDataType.Zip64ExtendedInformationExtraField
-                => new Zip64ExtendedInformationExtraField(type, length, extraData),
+            ExtraDataType.UnicodePathExtraField => new ExtraUnicodePathExtraField(
+                type,
+                length,
+                extraData
+            ),
+            ExtraDataType.Zip64ExtendedInformationExtraField =>
+                new Zip64ExtendedInformationExtraField(type, length, extraData),
             ExtraDataType.UnixTimeExtraField => new UnixTimeExtraField(type, length, extraData),
-            _ => new ExtraData(type, length, extraData)
+            _ => new ExtraData(type, length, extraData),
         };
 }

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

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Buffers.Binary;
 using System.Collections.Generic;
@@ -20,21 +18,21 @@ internal abstract class ZipFileEntry : ZipHeader
     {
         get
         {
-            if (Name.EndsWith('/'))
+            if (Name?.EndsWith('/') ?? false)
             {
                 return true;
             }
 
             //.NET Framework 4.5 : System.IO.Compression::CreateFromDirectory() probably writes backslashes to headers
-            return CompressedSize == 0 && UncompressedSize == 0 && Name.EndsWith('\\');
+            return CompressedSize == 0 && UncompressedSize == 0 && (Name?.EndsWith('\\') ?? false);
         }
     }
 
-    internal Stream PackedStream { get; set; }
+    internal Stream? PackedStream { get; set; }
 
     internal ArchiveEncoding ArchiveEncoding { get; }
 
-    internal string Name { get; set; }
+    internal string? Name { get; set; }
 
     internal HeaderFlags Flags { get; set; }
 
@@ -48,7 +46,7 @@ internal abstract class ZipFileEntry : ZipHeader
 
     internal List<ExtraData> Extra { get; set; }
 
-    public string Password { get; set; }
+    public string? Password { get; set; }
 
     internal PkwareTraditionalEncryptionData ComposeEncryptionData(Stream archiveStream)
     {
@@ -65,7 +63,7 @@ internal abstract class ZipFileEntry : ZipHeader
         return encryptionData;
     }
 
-    internal WinzipAesEncryptionData WinzipAesEncryptionData { get; set; }
+    internal WinzipAesEncryptionData? WinzipAesEncryptionData { get; set; }
 
     /// <summary>
     /// The last modified date as read from the Local or Central Directory header.
@@ -119,7 +117,7 @@ internal abstract class ZipFileEntry : ZipHeader
         }
     }
 
-    internal ZipFilePart Part { get; set; }
+    internal ZipFilePart? Part { get; set; }
 
     internal bool IsZip64 => CompressedSize >= uint.MaxValue;
 }

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

@@ -8,5 +8,5 @@ internal enum ZipHeaderType
     DirectoryEnd,
     Split,
     Zip64DirectoryEnd,
-    Zip64DirectoryEndLocator
+    Zip64DirectoryEndLocator,
 }

src/SharpCompress/Common/Zip/PkwareTraditionalCryptoStream.cs

@@ -6,7 +6,7 @@ namespace SharpCompress.Common.Zip;
 internal enum CryptoMode
 {
     Encrypt,
-    Decrypt
+    Decrypt,
 }
 
 internal class PkwareTraditionalCryptoStream : Stream

src/SharpCompress/Common/Zip/PkwareTraditionalEncryptionData.cs

@@ -103,7 +103,7 @@ internal class PkwareTraditionalEncryptionData
 
     internal byte[] StringToByteArray(string value)
     {
-        var a = _archiveEncoding.Password.GetBytes(value);
+        var a = _archiveEncoding.GetPasswordEncoding().GetBytes(value);
         return a;
     }
 

src/SharpCompress/Common/Zip/SeekableZipFilePart.cs

@@ -42,16 +42,16 @@ internal class SeekableZipFilePart : ZipFilePart
 
     protected override Stream CreateBaseStream()
     {
-        BaseStream.Position = Header.DataStartPosition!.Value;
+        BaseStream.Position = Header.DataStartPosition.NotNull();
 
         if (
             (Header.CompressedSize == 0)
             && FlagUtility.HasFlag(Header.Flags, HeaderFlags.UsePostDataDescriptor)
-            && (_directoryEntryHeader?.HasData == true)
-            && (_directoryEntryHeader?.CompressedSize != 0)
+            && _directoryEntryHeader.HasData
+            && (_directoryEntryHeader.CompressedSize != 0)
         )
         {
-            return new ReadOnlySubStream(BaseStream, _directoryEntryHeader!.CompressedSize);
+            return new ReadOnlySubStream(BaseStream, _directoryEntryHeader.CompressedSize);
         }
 
         return BaseStream;

src/SharpCompress/Common/Zip/StreamingZipFilePart.cs

@@ -13,7 +13,7 @@ internal sealed class StreamingZipFilePart : ZipFilePart
     internal StreamingZipFilePart(ZipFileEntry header, Stream stream)
         : base(header, stream) { }
 
-    protected override Stream CreateBaseStream() => Header.PackedStream;
+    protected override Stream CreateBaseStream() => Header.PackedStream.NotNull();
 
     internal override Stream GetCompressedStream()
     {

src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs

@@ -36,16 +36,19 @@ internal class StreamingZipHeaderFactory : ZipHeaderFactory
             uint headerBytes = 0;
             if (
                 _lastEntryHeader != null
-                && (
-                    FlagUtility.HasFlag(_lastEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor)
-                    || _lastEntryHeader.IsZip64
-                )
+                && FlagUtility.HasFlag(_lastEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor)
             )
             {
+                if (_lastEntryHeader.Part is null)
+                {
+                    continue;
+                }
                 reader = ((StreamingZipFilePart)_lastEntryHeader.Part).FixStreamedFileLocation(
                     ref rewindableStream
                 );
+
                 var pos = rewindableStream.CanSeek ? (long?)rewindableStream.Position : null;
+
                 var crc = reader.ReadUInt32();
                 if (crc == POST_DATA_DESCRIPTOR)
                 {
@@ -78,6 +81,60 @@ internal class StreamingZipHeaderFactory : ZipHeaderFactory
                     _lastEntryHeader.DataStartPosition = pos - _lastEntryHeader.CompressedSize;
                 }
             }
+            else if (_lastEntryHeader != null && _lastEntryHeader.IsZip64)
+            {
+                if (_lastEntryHeader.Part is null)
+                    continue;
+
+                reader = ((StreamingZipFilePart)_lastEntryHeader.Part).FixStreamedFileLocation(
+                    ref rewindableStream
+                );
+
+                var pos = rewindableStream.CanSeek ? (long?)rewindableStream.Position : null;
+
+                headerBytes = reader.ReadUInt32();
+
+                var version = reader.ReadUInt16();
+                var flags = (HeaderFlags)reader.ReadUInt16();
+                var compressionMethod = (ZipCompressionMethod)reader.ReadUInt16();
+                var lastModifiedDate = reader.ReadUInt16();
+                var lastModifiedTime = reader.ReadUInt16();
+
+                var crc = reader.ReadUInt32();
+
+                if (crc == POST_DATA_DESCRIPTOR)
+                {
+                    crc = reader.ReadUInt32();
+                }
+                _lastEntryHeader.Crc = crc;
+
+                // The DataDescriptor can be either 64bit or 32bit
+                var compressed_size = reader.ReadUInt32();
+                var uncompressed_size = reader.ReadUInt32();
+
+                // Check if we have header or 64bit DataDescriptor
+                var test_header = !(headerBytes == 0x04034b50 || headerBytes == 0x02014b50);
+
+                var test_64bit = ((long)uncompressed_size << 32) | compressed_size;
+                if (test_64bit == _lastEntryHeader.CompressedSize && test_header)
+                {
+                    _lastEntryHeader.UncompressedSize =
+                        ((long)reader.ReadUInt32() << 32) | headerBytes;
+                    headerBytes = reader.ReadUInt32();
+                }
+                else
+                {
+                    _lastEntryHeader.UncompressedSize = uncompressed_size;
+                }
+
+                if (pos.HasValue)
+                {
+                    _lastEntryHeader.DataStartPosition = pos - _lastEntryHeader.CompressedSize;
+
+                    // 4 = First 4 bytes of the entry header (i.e. 50 4B 03 04)
+                    rewindableStream.Position = pos.Value + 4;
+                }
+            }
             else
             {
                 headerBytes = reader.ReadUInt32();

src/SharpCompress/Common/Zip/WinzipAesEncryptionData.cs

@@ -1,5 +1,3 @@
-#nullable disable
-
 using System;
 using System.Buffers.Binary;
 using System.Security.Cryptography;
@@ -10,12 +8,7 @@ internal class WinzipAesEncryptionData
 {
     private const int RFC2898_ITERATIONS = 1000;
 
-    private readonly byte[] _salt;
     private readonly WinzipAesKeySize _keySize;
-    private readonly byte[] _passwordVerifyValue;
-    private readonly string _password;
-
-    private byte[] _generatedVerifyValue;
 
     internal WinzipAesEncryptionData(
         WinzipAesKeySize keySize,
@@ -25,10 +18,28 @@ internal class WinzipAesEncryptionData
     )
     {
         _keySize = keySize;
-        _salt = salt;
-        _passwordVerifyValue = passwordVerifyValue;
-        _password = password;
-        Initialize();
+
+#if NETFRAMEWORK || NETSTANDARD2_0
+        var rfc2898 = new Rfc2898DeriveBytes(password, salt, RFC2898_ITERATIONS);
+#else
+        var rfc2898 = new Rfc2898DeriveBytes(
+            password,
+            salt,
+            RFC2898_ITERATIONS,
+            HashAlgorithmName.SHA1
+        );
+#endif
+
+        KeyBytes = rfc2898.GetBytes(KeySizeInBytes); // 16 or 24 or 32 ???
+        IvBytes = rfc2898.GetBytes(KeySizeInBytes);
+        var generatedVerifyValue = rfc2898.GetBytes(2);
+
+        var verify = BinaryPrimitives.ReadInt16LittleEndian(passwordVerifyValue);
+        var generated = BinaryPrimitives.ReadInt16LittleEndian(generatedVerifyValue);
+        if (verify != generated)
+        {
+            throw new InvalidFormatException("bad password");
+        }
     }
 
     internal byte[] IvBytes { get; set; }
@@ -45,32 +56,4 @@ internal class WinzipAesEncryptionData
             WinzipAesKeySize.KeySize256 => 32,
             _ => throw new InvalidOperationException(),
         };
-
-    private void Initialize()
-    {
-#if NETFRAMEWORK || NETSTANDARD2_0
-        var rfc2898 = new Rfc2898DeriveBytes(_password, _salt, RFC2898_ITERATIONS);
-#else
-        var rfc2898 = new Rfc2898DeriveBytes(
-            _password,
-            _salt,
-            RFC2898_ITERATIONS,
-            HashAlgorithmName.SHA1
-        );
-#endif
-
-        KeyBytes = rfc2898.GetBytes(KeySizeInBytes); // 16 or 24 or 32 ???
-        IvBytes = rfc2898.GetBytes(KeySizeInBytes);
-        _generatedVerifyValue = rfc2898.GetBytes(2);
-
-        var verify = BinaryPrimitives.ReadInt16LittleEndian(_passwordVerifyValue);
-        if (_password != null)
-        {
-            var generated = BinaryPrimitives.ReadInt16LittleEndian(_generatedVerifyValue);
-            if (verify != generated)
-            {
-                throw new InvalidFormatException("bad password");
-            }
-        }
-    }
 }

src/SharpCompress/Common/Zip/WinzipAesKeySize.cs

@@ -4,5 +4,5 @@ internal enum WinzipAesKeySize
 {
     KeySize128 = 1,
     KeySize192 = 2,
-    KeySize256 = 3
+    KeySize256 = 3,
 }

src/SharpCompress/Common/Zip/ZipCompressionMethod.cs

@@ -4,6 +4,11 @@ internal enum ZipCompressionMethod
 {
     None = 0,
     Shrink = 1,
+    Reduce1 = 2,
+    Reduce2 = 3,
+    Reduce3 = 4,
+    Reduce4 = 5,
+    Explode = 6,
     Deflate = 8,
     Deflate64 = 9,
     BZip2 = 12,
@@ -11,5 +16,5 @@ internal enum ZipCompressionMethod
     ZStd = 93,
     Xz = 95,
     PPMd = 98,
-    WinzipAes = 0x63 //http://www.winzip.com/aes_info.htm
+    WinzipAes = 0x63, //http://www.winzip.com/aes_info.htm
 }

src/SharpCompress/Common/Zip/ZipEntry.cs

@@ -1,29 +1,38 @@
-#nullable disable
-
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using SharpCompress.Common.Zip.Headers;
 
 namespace SharpCompress.Common.Zip;
 
 public class ZipEntry : Entry
 {
-    private readonly ZipFilePart _filePart;
+    private readonly ZipFilePart? _filePart;
 
-    internal ZipEntry(ZipFilePart filePart)
+    internal ZipEntry(ZipFilePart? filePart)
     {
-        if (filePart != null)
+        if (filePart == null)
         {
-            _filePart = filePart;
-            LastModifiedTime = Utility.DosDateToDateTime(
-                filePart.Header.LastModifiedDate,
-                filePart.Header.LastModifiedTime
-            );
+            return;
         }
+        _filePart = filePart;
+
+        LastModifiedTime = Utility.DosDateToDateTime(
+            filePart.Header.LastModifiedDate,
+            filePart.Header.LastModifiedTime
+        );
+
+        var times =
+            filePart.Header.Extra.FirstOrDefault(header =>
+                header.GetType() == typeof(UnixTimeExtraField)
+            ) as UnixTimeExtraField;
+
+        LastAccessedTime = times?.UnicodeTimes.Item2;
+        CreatedTime = times?.UnicodeTimes.Item3;
     }
 
     public override CompressionType CompressionType =>
-        _filePart.Header.CompressionMethod switch
+        _filePart?.Header.CompressionMethod switch
         {
             ZipCompressionMethod.BZip2 => CompressionType.BZip2,
             ZipCompressionMethod.Deflate => CompressionType.Deflate,
@@ -32,33 +41,46 @@ public class ZipEntry : Entry
             ZipCompressionMethod.PPMd => CompressionType.PPMd,
             ZipCompressionMethod.None => CompressionType.None,
             ZipCompressionMethod.Shrink => CompressionType.Shrink,
-            _ => CompressionType.Unknown
+            ZipCompressionMethod.Reduce1 => CompressionType.Reduce1,
+            ZipCompressionMethod.Reduce2 => CompressionType.Reduce2,
+            ZipCompressionMethod.Reduce3 => CompressionType.Reduce3,
+            ZipCompressionMethod.Reduce4 => CompressionType.Reduce4,
+            ZipCompressionMethod.Explode => CompressionType.Explode,
+            _ => CompressionType.Unknown,
         };
 
-    public override long Crc => _filePart.Header.Crc;
+    public override long Crc => _filePart?.Header.Crc ?? 0;
 
-    public override string Key => _filePart.Header.Name;
+    public override string? Key => _filePart?.Header.Name;
 
-    public override string LinkTarget => null;
+    public override string? LinkTarget => null;
 
-    public override long CompressedSize => _filePart.Header.CompressedSize;
+    public override long CompressedSize => _filePart?.Header.CompressedSize ?? 0;
 
-    public override long Size => _filePart.Header.UncompressedSize;
+    public override long Size => _filePart?.Header.UncompressedSize ?? 0;
 
     public override DateTime? LastModifiedTime { get; }
 
-    public override DateTime? CreatedTime => null;
+    /// <inheritdoc/>
+    /// <remarks>
+    /// The returned time is UTC, not local.
+    /// </remarks>
+    public override DateTime? CreatedTime { get; }
 
-    public override DateTime? LastAccessedTime => null;
+    /// <inheritdoc/>
+    /// <remarks>
+    /// The returned time is UTC, not local.
+    /// </remarks>
+    public override DateTime? LastAccessedTime { get; }
 
     public override DateTime? ArchivedTime => null;
 
     public override bool IsEncrypted =>
-        FlagUtility.HasFlag(_filePart.Header.Flags, HeaderFlags.Encrypted);
+        FlagUtility.HasFlag(_filePart?.Header.Flags ?? HeaderFlags.None, HeaderFlags.Encrypted);
 
-    public override bool IsDirectory => _filePart.Header.IsDirectory;
+    public override bool IsDirectory => _filePart?.Header.IsDirectory ?? false;
 
     public override bool IsSplitAfter => false;
 
-    internal override IEnumerable<FilePart> Parts => _filePart.AsEnumerable<FilePart>();
+    internal override IEnumerable<FilePart> Parts => _filePart.Empty();
 }

src/SharpCompress/Common/Zip/ZipFilePart.cs

@@ -7,8 +7,10 @@ using SharpCompress.Compressors;
 using SharpCompress.Compressors.BZip2;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.Compressors.Deflate64;
+using SharpCompress.Compressors.Explode;
 using SharpCompress.Compressors.LZMA;
 using SharpCompress.Compressors.PPMd;
+using SharpCompress.Compressors.Reduce;
 using SharpCompress.Compressors.Shrink;
 using SharpCompress.Compressors.Xz;
 using SharpCompress.IO;
@@ -29,7 +31,7 @@ internal abstract class ZipFilePart : FilePart
     internal Stream BaseStream { get; }
     internal ZipFileEntry Header { get; set; }
 
-    internal override string FilePartName => Header.Name;
+    internal override string? FilePartName => Header.Name;
 
     internal override Stream GetCompressedStream()
     {
@@ -89,6 +91,32 @@ internal abstract class ZipFilePart : FilePart
                     Header.UncompressedSize
                 );
             }
+            case ZipCompressionMethod.Reduce1:
+            {
+                return new ReduceStream(stream, Header.CompressedSize, Header.UncompressedSize, 1);
+            }
+            case ZipCompressionMethod.Reduce2:
+            {
+                return new ReduceStream(stream, Header.CompressedSize, Header.UncompressedSize, 2);
+            }
+            case ZipCompressionMethod.Reduce3:
+            {
+                return new ReduceStream(stream, Header.CompressedSize, Header.UncompressedSize, 3);
+            }
+            case ZipCompressionMethod.Reduce4:
+            {
+                return new ReduceStream(stream, Header.CompressedSize, Header.UncompressedSize, 4);
+            }
+            case ZipCompressionMethod.Explode:
+            {
+                return new ExplodeStream(
+                    stream,
+                    Header.CompressedSize,
+                    Header.UncompressedSize,
+                    Header.Flags
+                );
+            }
+
             case ZipCompressionMethod.Deflate:
             {
                 return new DeflateStream(stream, CompressionMode.Decompress);
@@ -203,6 +231,10 @@ internal abstract class ZipFilePart : FilePart
             {
                 case ZipCompressionMethod.None:
                 case ZipCompressionMethod.Shrink:
+                case ZipCompressionMethod.Reduce1:
+                case ZipCompressionMethod.Reduce2:
+                case ZipCompressionMethod.Reduce3:
+                case ZipCompressionMethod.Reduce4:
                 case ZipCompressionMethod.Deflate:
                 case ZipCompressionMethod.Deflate64:
                 case ZipCompressionMethod.BZip2:

src/SharpCompress/Common/Zip/ZipHeaderFactory.cs

@@ -55,7 +55,13 @@ internal class ZipHeaderFactory
             }
             case POST_DATA_DESCRIPTOR:
             {
-                if (FlagUtility.HasFlag(_lastEntryHeader!.Flags, HeaderFlags.UsePostDataDescriptor))
+                if (
+                    _lastEntryHeader != null
+                    && FlagUtility.HasFlag(
+                        _lastEntryHeader.NotNull().Flags,
+                        HeaderFlags.UsePostDataDescriptor
+                    )
+                )
                 {
                     _lastEntryHeader.Crc = reader.ReadUInt32();
                     _lastEntryHeader.CompressedSize = zip64

src/SharpCompress/Compressors/BZip2/BZip2Constants.cs

@@ -555,6 +555,6 @@ internal class BZip2Constants
         858,
         364,
         936,
-        638
+        638,
     };
 }

src/SharpCompress/Compressors/BZip2/BZip2Stream.cs

@@ -69,7 +69,7 @@ public sealed class BZip2Stream : Stream
 
     public override void SetLength(long value) => stream.SetLength(value);
 
-#if !NETFRAMEWORK && !NETSTANDARD2_0
+#if !NETFRAMEWORK&& !NETSTANDARD2_0
 
     public override int Read(Span<byte> buffer) => stream.Read(buffer);
 

src/SharpCompress/Compressors/BZip2/CBZip2InputStream.cs

@@ -1,4 +1,4 @@
-#nullable disable
+#nullable disable
 
 using System;
 using System.IO;
@@ -42,14 +42,17 @@ internal class CBZip2InputStream : Stream
     private static void Cadvise()
     {
         //System.out.Println("CRC Error");
-        //throw new CCoruptionError();
+        throw new InvalidOperationException("BZip2 error");
     }
 
     private static void BadBGLengths() => Cadvise();
 
     private static void BitStreamEOF() => Cadvise();
 
-    private static void CompressedStreamEOF() => Cadvise();
+    private static void CompressedStreamEOF()
+    {
+        throw new InvalidOperationException("BZip2 compressed file ends unexpectedly");
+    }
 
     private void MakeMaps()
     {

src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs

@@ -1829,7 +1829,7 @@ internal sealed class CBZip2OutputStream : Stream
         88573,
         265720,
         797161,
-        2391484
+        2391484,
     };
 
     private void AllocateCompressStructures()

src/SharpCompress/Compressors/BZip2/CRC.cs

@@ -288,7 +288,7 @@ internal class CRC
         unchecked((int)0xbcb4666d),
         unchecked((int)0xb8757bda),
         unchecked((int)0xb5365d03),
-        unchecked((int)0xb1f740b4)
+        unchecked((int)0xb1f740b4),
     };
 
     public CRC() => InitialiseCRC();

src/SharpCompress/Compressors/CompressionMode.cs

@@ -3,5 +3,5 @@ namespace SharpCompress.Compressors;
 public enum CompressionMode
 {
     Compress = 0,
-    Decompress = 1
+    Decompress = 1,
 }

src/SharpCompress/Compressors/Deflate/DeflateManager.cs

@@ -106,7 +106,7 @@ internal sealed partial class DeflateManager
         5,
         5,
         5,
-        0
+        0,
     };
 
     // extra bits for each distance code
@@ -141,7 +141,7 @@ internal sealed partial class DeflateManager
         12,
         12,
         13,
-        13
+        13,
     };
 
     internal enum BlockState
@@ -149,14 +149,14 @@ internal sealed partial class DeflateManager
         NeedMore = 0, // block not completed, need more input or more output
         BlockDone, // block flush performed
         FinishStarted, // finish started, need only more output at next deflate
-        FinishDone // finish done, accept no more input or output
+        FinishDone, // finish done, accept no more input or output
     }
 
     internal enum DeflateFlavor
     {
         Store,
         Fast,
-        Slow
+        Slow,
     }
 
     private const int MEM_LEVEL_MAX = 9;
@@ -214,7 +214,7 @@ internal sealed partial class DeflateManager
                 new Config(8, 16, 128, 128, DeflateFlavor.Slow),
                 new Config(8, 32, 128, 256, DeflateFlavor.Slow),
                 new Config(32, 128, 258, 1024, DeflateFlavor.Slow),
-                new Config(32, 258, 258, 4096, DeflateFlavor.Slow)
+                new Config(32, 258, 258, 4096, DeflateFlavor.Slow),
             };
 
         private static readonly Config[] Table;
@@ -233,7 +233,7 @@ internal sealed partial class DeflateManager
         "insufficient memory",
         "buffer error",
         "incompatible version",
-        ""
+        "",
     };
 
     // preset dictionary flag in zlib header
@@ -1793,7 +1793,7 @@ internal sealed partial class DeflateManager
             DeflateFlavor.Store => DeflateNone,
             DeflateFlavor.Fast => DeflateFast,
             DeflateFlavor.Slow => DeflateSlow,
-            _ => DeflateFunction
+            _ => DeflateFunction,
         };
 
     internal int SetParams(CompressionLevel level, CompressionStrategy strategy)

src/SharpCompress/Compressors/Deflate/FlushType.cs

@@ -39,5 +39,5 @@ public enum FlushType
     Full,
 
     /// <summary>Signals the end of the compression/decompression stream.</summary>
-    Finish
+    Finish,
 }

src/SharpCompress/Compressors/Deflate/InfTree.cs

@@ -1615,7 +1615,7 @@ internal sealed class InfTree
         79,
         0,
         9,
-        255
+        255,
     };
 
     //UPGRADE_NOTE: Final was removed from the declaration of 'fixed_td'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
@@ -1716,7 +1716,7 @@ internal sealed class InfTree
         193,
         192,
         5,
-        24577
+        24577,
     };
 
     // Tables for deflate from PKZIP's appnote.txt.
@@ -1753,7 +1753,7 @@ internal sealed class InfTree
         227,
         258,
         0,
-        0
+        0,
     };
 
     // see note #13 above about 258
@@ -1790,7 +1790,7 @@ internal sealed class InfTree
         5,
         0,
         112,
-        112
+        112,
     };
 
     //UPGRADE_NOTE: Final was removed from the declaration of 'cpdist'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
@@ -1825,7 +1825,7 @@ internal sealed class InfTree
         8193,
         12289,
         16385,
-        24577
+        24577,
     };
 
     //UPGRADE_NOTE: Final was removed from the declaration of 'cpdext'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
@@ -1860,7 +1860,7 @@ internal sealed class InfTree
         12,
         12,
         13,
-        13
+        13,
     };
 
     // If BMAX needs to be larger than 16, then h and x[] should be uLong.

src/SharpCompress/Compressors/Deflate/Inflate.cs

@@ -93,7 +93,7 @@ internal sealed class InflateBlocks
         2,
         14,
         1,
-        15
+        15,
     };
 
     internal ZlibCodec _codec; // pointer back to this zlib stream
@@ -815,7 +815,7 @@ internal sealed class InflateBlocks
         CODES = 6, // processing fixed or dynamic block
         DRY = 7, // output remaining window bytes
         DONE = 8, // finished last block, done
-        BAD = 9 // ot a data error--stuck here
+        BAD = 9, // ot a data error--stuck here
     }
 
     #endregion
@@ -842,7 +842,7 @@ internal static class InternalInflateConstants
         0x00001fff,
         0x00003fff,
         0x00007fff,
-        0x0000ffff
+        0x0000ffff,
     };
 }
 
@@ -2054,7 +2054,7 @@ internal sealed class InflateManager
         CHECK2 = 10, // two check bytes to go
         CHECK1 = 11, // one check byte to go
         DONE = 12, // finished check, done
-        BAD = 13 // got an error--stay here
+        BAD = 13, // got an error--stay here
     }
 
     #endregion

src/SharpCompress/Compressors/Deflate/Tree.cs

@@ -95,7 +95,7 @@ internal sealed partial class DeflateManager
             2,
             14,
             1,
-            15
+            15,
         };
 
         // The lengths of the bit length codes are sent in order of decreasing
@@ -618,7 +618,7 @@ internal sealed partial class DeflateManager
             29,
             29,
             29,
-            29
+            29,
         };
 
         internal static readonly sbyte[] LengthCode =
@@ -878,7 +878,7 @@ internal sealed partial class DeflateManager
             27,
             27,
             27,
-            28
+            28,
         };
 
         internal static readonly int[] LengthBase =
@@ -911,7 +911,7 @@ internal sealed partial class DeflateManager
             160,
             192,
             224,
-            0
+            0,
         };
 
         internal static readonly int[] DistanceBase =
@@ -945,7 +945,7 @@ internal sealed partial class DeflateManager
             8192,
             12288,
             16384,
-            24576
+            24576,
         };
 
         internal short[] dyn_tree; // the dynamic tree

src/SharpCompress/Compressors/Deflate/Zlib.cs

@@ -143,7 +143,7 @@ public enum CompressionLevel
     /// <summary>
     /// A synonym for BestCompression.
     /// </summary>
-    Level9 = BestCompression
+    Level9 = BestCompression,
 }
 
 /// <summary>
@@ -171,7 +171,7 @@ public enum CompressionStrategy
     /// Using <c>HuffmanOnly</c> will force the compressor to do Huffman encoding only, with no
     /// string matching.
     /// </summary>
-    HuffmanOnly = 2
+    HuffmanOnly = 2,
 }
 
 /// <summary>
@@ -859,7 +859,7 @@ internal sealed class StaticTree
         99,
         8,
         227,
-        8
+        8,
     };
 
     internal static readonly short[] distTreeCodes =
@@ -923,7 +923,7 @@ internal sealed class StaticTree
         7,
         5,
         23,
-        5
+        5,
     };
 
     // extra bits for each bit length code
@@ -947,7 +947,7 @@ internal sealed class StaticTree
         0,
         2,
         3,
-        7
+        7,
     };
 
     internal static readonly StaticTree Literals;

src/SharpCompress/Compressors/Deflate/ZlibBaseStream.cs

@@ -39,7 +39,7 @@ internal enum ZlibStreamFlavor
 {
     ZLIB = 1950,
     DEFLATE = 1951,
-    GZIP = 1952
+    GZIP = 1952,
 }
 
 internal class ZlibBaseStream : Stream
@@ -655,6 +655,6 @@ internal class ZlibBaseStream : Stream
     {
         Writer,
         Reader,
-        Undefined
+        Undefined,
     }
 }

src/SharpCompress/Compressors/Deflate64/BlockType.cs

@@ -8,5 +8,5 @@ internal enum BlockType
 {
     Uncompressed = 0,
     Static = 1,
-    Dynamic = 2
+    Dynamic = 2,
 }

src/SharpCompress/Compressors/Deflate64/FastEncoderStatus.cs

@@ -111,7 +111,7 @@ internal static class FastEncoderStatics
             0x7e,
             0x7c,
             0x1f,
-            0x3f
+            0x3f,
         };
 
     internal static ReadOnlySpan<byte> B_FINAL_FAST_ENCODER_TREE_STRUCTURE_DATA =>
@@ -214,7 +214,7 @@ internal static class FastEncoderStatics
             0x7e,
             0x7c,
             0x1f,
-            0x3f
+            0x3f,
         };
 
     // Output a currentMatch with length matchLen (>= MIN_MATCH) and displacement matchPos
@@ -762,7 +762,7 @@ internal static class FastEncoderStatics
         0x0039e7f1,
         0x003be7f1,
         0x003de7f1,
-        0x000047eb
+        0x000047eb,
     };
 
     internal static readonly uint[] FAST_ENCODER_DISTANCE_CODE_INFO =
@@ -798,7 +798,7 @@ internal static class FastEncoderStatics
         0x000007d5,
         0x000017d5,
         0x00000000,
-        0x00000100
+        0x00000100,
     };
 
     internal static readonly uint[] BIT_MASK =
@@ -818,7 +818,7 @@ internal static class FastEncoderStatics
         4095,
         8191,
         16383,
-        32767
+        32767,
     };
     internal static readonly byte[] EXTRA_LENGTH_BITS =
     {
@@ -850,7 +850,7 @@ internal static class FastEncoderStatics
         5,
         5,
         5,
-        0
+        0,
     };
     internal static readonly byte[] EXTRA_DISTANCE_BITS =
     {
@@ -885,7 +885,7 @@ internal static class FastEncoderStatics
         13,
         13,
         0,
-        0
+        0,
     };
     internal const int NUM_CHARS = 256;
     internal const int NUM_LENGTH_BASE_CODES = 29;

src/SharpCompress/Compressors/Deflate64/InflaterManaged.cs

@@ -70,7 +70,7 @@ internal sealed class InflaterManaged
             5,
             5,
             5,
-            16
+            16,
         };
 
     // The base length for length code 257 - 285.
@@ -105,7 +105,7 @@ internal sealed class InflaterManaged
         163,
         195,
         227,
-        3
+        3,
     };
 
     // The base distance for distance code 0 - 31
@@ -143,7 +143,7 @@ internal sealed class InflaterManaged
         16385,
         24577,
         32769,
-        49153
+        49153,
     };
 
     // code lengths for code length alphabet is stored in following order
@@ -184,7 +184,7 @@ internal sealed class InflaterManaged
             0x07,
             0x17,
             0x0f,
-            0x1f
+            0x1f,
         };
 
     private readonly OutputWindow _output;

src/SharpCompress/Compressors/Deflate64/InflaterState.cs

@@ -37,5 +37,5 @@ internal enum InflaterState
     ReadingFooter = 22,
     VerifyingFooter = 23,
 
-    Done = 24 // Finished
+    Done = 24, // Finished
 }

src/SharpCompress/Compressors/Deflate64/MatchState.cs

@@ -8,5 +8,5 @@ internal enum MatchState
 {
     HasSymbol = 1,
     HasMatch = 2,
-    HasSymbolAndMatch = 3
+    HasSymbolAndMatch = 3,
 }

src/SharpCompress/Compressors/Explode/ExplodeStream.cs

@@ -0,0 +1,746 @@
+using System;
+using System.IO;
+using SharpCompress.Common.Zip.Headers;
+
+namespace SharpCompress.Compressors.Explode;
+
+public class ExplodeStream : Stream
+{
+    private const int INVALID_CODE = 99;
+    private const int WSIZE = 64 * 1024;
+
+    private readonly long unCompressedSize;
+    private readonly int compressedSize;
+    private readonly HeaderFlags generalPurposeBitFlag;
+    private readonly Stream inStream;
+
+    private huftNode[]? hufLiteralCodeTable; /* literal code table */
+    private huftNode[] hufLengthCodeTable = []; /* length code table */
+    private huftNode[] hufDistanceCodeTable = []; /* distance code table */
+
+    private int bitsForLiteralCodeTable;
+    private int bitsForLengthCodeTable;
+    private int bitsForDistanceCodeTable;
+    private int numOfUncodedLowerDistanceBits; /* number of uncoded lower distance bits */
+
+    private ulong bitBuffer;
+    private int bitBufferCount;
+
+    private readonly byte[] windowsBuffer;
+    private uint maskForLiteralCodeTable;
+    private uint maskForLengthCodeTable;
+    private uint maskForDistanceCodeTable;
+    private uint maskForDistanceLowBits;
+    private long outBytesCount;
+
+    private int windowIndex;
+    private int distance;
+    private int length;
+
+    internal ExplodeStream(
+        Stream inStr,
+        long compressedSize,
+        long uncompressedSize,
+        HeaderFlags generalPurposeBitFlag
+    )
+    {
+        inStream = inStr;
+        this.compressedSize = (int)compressedSize;
+        unCompressedSize = (long)uncompressedSize;
+        this.generalPurposeBitFlag = generalPurposeBitFlag;
+        explode_SetTables();
+
+        windowsBuffer = new byte[WSIZE];
+        explode_var_init();
+    }
+
+    public override void Flush()
+    {
+        throw new NotImplementedException();
+    }
+
+    public override long Seek(long offset, SeekOrigin origin)
+    {
+        throw new NotImplementedException();
+    }
+
+    public override void SetLength(long value)
+    {
+        throw new NotImplementedException();
+    }
+
+    public override void Write(byte[] buffer, int offset, int count)
+    {
+        throw new NotImplementedException();
+    }
+
+    public override bool CanRead => true;
+    public override bool CanSeek => false;
+    public override bool CanWrite => false;
+    public override long Length => unCompressedSize;
+    public override long Position
+    {
+        get => outBytesCount;
+        set { }
+    }
+
+    static uint[] mask_bits = new uint[]
+    {
+        0x0000,
+        0x0001,
+        0x0003,
+        0x0007,
+        0x000f,
+        0x001f,
+        0x003f,
+        0x007f,
+        0x00ff,
+        0x01ff,
+        0x03ff,
+        0x07ff,
+        0x0fff,
+        0x1fff,
+        0x3fff,
+        0x7fff,
+        0xffff,
+    };
+
+    /* Tables for length and distance */
+    static int[] cplen2 = new int[]
+    {
+        2,
+        3,
+        4,
+        5,
+        6,
+        7,
+        8,
+        9,
+        10,
+        11,
+        12,
+        13,
+        14,
+        15,
+        16,
+        17,
+        18,
+        19,
+        20,
+        21,
+        22,
+        23,
+        24,
+        25,
+        26,
+        27,
+        28,
+        29,
+        30,
+        31,
+        32,
+        33,
+        34,
+        35,
+        36,
+        37,
+        38,
+        39,
+        40,
+        41,
+        42,
+        43,
+        44,
+        45,
+        46,
+        47,
+        48,
+        49,
+        50,
+        51,
+        52,
+        53,
+        54,
+        55,
+        56,
+        57,
+        58,
+        59,
+        60,
+        61,
+        62,
+        63,
+        64,
+        65,
+    };
+
+    static int[] cplen3 = new int[]
+    {
+        3,
+        4,
+        5,
+        6,
+        7,
+        8,
+        9,
+        10,
+        11,
+        12,
+        13,
+        14,
+        15,
+        16,
+        17,
+        18,
+        19,
+        20,
+        21,
+        22,
+        23,
+        24,
+        25,
+        26,
+        27,
+        28,
+        29,
+        30,
+        31,
+        32,
+        33,
+        34,
+        35,
+        36,
+        37,
+        38,
+        39,
+        40,
+        41,
+        42,
+        43,
+        44,
+        45,
+        46,
+        47,
+        48,
+        49,
+        50,
+        51,
+        52,
+        53,
+        54,
+        55,
+        56,
+        57,
+        58,
+        59,
+        60,
+        61,
+        62,
+        63,
+        64,
+        65,
+        66,
+    };
+
+    static int[] extra = new int[]
+    {
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        8,
+    };
+
+    static int[] cpdist4 = new int[]
+    {
+        1,
+        65,
+        129,
+        193,
+        257,
+        321,
+        385,
+        449,
+        513,
+        577,
+        641,
+        705,
+        769,
+        833,
+        897,
+        961,
+        1025,
+        1089,
+        1153,
+        1217,
+        1281,
+        1345,
+        1409,
+        1473,
+        1537,
+        1601,
+        1665,
+        1729,
+        1793,
+        1857,
+        1921,
+        1985,
+        2049,
+        2113,
+        2177,
+        2241,
+        2305,
+        2369,
+        2433,
+        2497,
+        2561,
+        2625,
+        2689,
+        2753,
+        2817,
+        2881,
+        2945,
+        3009,
+        3073,
+        3137,
+        3201,
+        3265,
+        3329,
+        3393,
+        3457,
+        3521,
+        3585,
+        3649,
+        3713,
+        3777,
+        3841,
+        3905,
+        3969,
+        4033,
+    };
+
+    static int[] cpdist8 = new int[]
+    {
+        1,
+        129,
+        257,
+        385,
+        513,
+        641,
+        769,
+        897,
+        1025,
+        1153,
+        1281,
+        1409,
+        1537,
+        1665,
+        1793,
+        1921,
+        2049,
+        2177,
+        2305,
+        2433,
+        2561,
+        2689,
+        2817,
+        2945,
+        3073,
+        3201,
+        3329,
+        3457,
+        3585,
+        3713,
+        3841,
+        3969,
+        4097,
+        4225,
+        4353,
+        4481,
+        4609,
+        4737,
+        4865,
+        4993,
+        5121,
+        5249,
+        5377,
+        5505,
+        5633,
+        5761,
+        5889,
+        6017,
+        6145,
+        6273,
+        6401,
+        6529,
+        6657,
+        6785,
+        6913,
+        7041,
+        7169,
+        7297,
+        7425,
+        7553,
+        7681,
+        7809,
+        7937,
+        8065,
+    };
+
+    private int get_tree(int[] arrBitLengths, int numberExpected)
+    /* Get the bit lengths for a code representation from the compressed
+       stream.  If get_tree() returns 4, then there is an error in the data.
+       Otherwise zero is returned. */
+    {
+        /* get bit lengths */
+        int inIndex = inStream.ReadByte() + 1; /* length/count pairs to read */
+        int outIndex = 0; /* next code */
+        do
+        {
+            int nextByte = inStream.ReadByte();
+            int bitLengthOfCodes = (nextByte & 0xf) + 1; /* bits in code (1..16) */
+            int numOfCodes = ((nextByte & 0xf0) >> 4) + 1; /* codes with those bits (1..16) */
+            if (outIndex + numOfCodes > numberExpected)
+                return 4; /* don't overflow arrBitLengths[] */
+            do
+            {
+                arrBitLengths[outIndex++] = bitLengthOfCodes;
+            } while ((--numOfCodes) != 0);
+        } while ((--inIndex) != 0);
+
+        return outIndex != numberExpected ? 4 : 0; /* should have read numberExpected of them */
+    }
+
+    private int explode_SetTables()
+    {
+        int returnCode; /* return codes */
+        int[] arrBitLengthsForCodes = new int[256]; /* bit lengths for codes */
+
+        bitsForLiteralCodeTable = 0; /* bits for tb */
+        bitsForLengthCodeTable = 7;
+        bitsForDistanceCodeTable = (compressedSize) > 200000 ? 8 : 7;
+
+        if ((generalPurposeBitFlag & HeaderFlags.Bit2) != 0)
+        /* With literal tree--minimum match length is 3 */
+        {
+            bitsForLiteralCodeTable = 9; /* base table size for literals */
+            if ((returnCode = get_tree(arrBitLengthsForCodes, 256)) != 0)
+                return returnCode;
+
+            if (
+                (
+                    returnCode = HuftTree.huftbuid(
+                        arrBitLengthsForCodes,
+                        256,
+                        256,
+                        [],
+                        [],
+                        out hufLiteralCodeTable,
+                        ref bitsForLiteralCodeTable
+                    )
+                ) != 0
+            )
+                return returnCode;
+
+            if ((returnCode = get_tree(arrBitLengthsForCodes, 64)) != 0)
+                return returnCode;
+
+            if (
+                (
+                    returnCode = HuftTree.huftbuid(
+                        arrBitLengthsForCodes,
+                        64,
+                        0,
+                        cplen3,
+                        extra,
+                        out hufLengthCodeTable,
+                        ref bitsForLengthCodeTable
+                    )
+                ) != 0
+            )
+                return returnCode;
+        }
+        else
+        /* No literal tree--minimum match length is 2 */
+        {
+            if ((returnCode = get_tree(arrBitLengthsForCodes, 64)) != 0)
+                return returnCode;
+
+            hufLiteralCodeTable = null;
+
+            if (
+                (
+                    returnCode = HuftTree.huftbuid(
+                        arrBitLengthsForCodes,
+                        64,
+                        0,
+                        cplen2,
+                        extra,
+                        out hufLengthCodeTable,
+                        ref bitsForLengthCodeTable
+                    )
+                ) != 0
+            )
+                return returnCode;
+        }
+
+        if ((returnCode = get_tree(arrBitLengthsForCodes, 64)) != 0)
+            return (int)returnCode;
+
+        if ((generalPurposeBitFlag & HeaderFlags.Bit1) != 0) /* true if 8K */
+        {
+            numOfUncodedLowerDistanceBits = 7;
+            returnCode = HuftTree.huftbuid(
+                arrBitLengthsForCodes,
+                64,
+                0,
+                cpdist8,
+                extra,
+                out hufDistanceCodeTable,
+                ref bitsForDistanceCodeTable
+            );
+        }
+        else /* else 4K */
+        {
+            numOfUncodedLowerDistanceBits = 6;
+            returnCode = HuftTree.huftbuid(
+                arrBitLengthsForCodes,
+                64,
+                0,
+                cpdist4,
+                extra,
+                out hufDistanceCodeTable,
+                ref bitsForDistanceCodeTable
+            );
+        }
+
+        return returnCode;
+    }
+
+    private void NeedBits(int numberOfBits)
+    {
+        while (bitBufferCount < (numberOfBits))
+        {
+            bitBuffer |= (uint)inStream.ReadByte() << bitBufferCount;
+            bitBufferCount += 8;
+        }
+    }
+
+    private void DumpBits(int numberOfBits)
+    {
+        bitBuffer >>= numberOfBits;
+        bitBufferCount -= numberOfBits;
+    }
+
+    int DecodeHuft(huftNode[] htab, int bits, uint mask, out huftNode huftPointer, out int e)
+    {
+        NeedBits(bits);
+
+        int tabOffset = (int)(~bitBuffer & mask);
+        huftPointer = htab[tabOffset];
+
+        while (true)
+        {
+            DumpBits(huftPointer.NumberOfBitsUsed);
+            e = huftPointer.NumberOfExtraBits;
+            if (e <= 32)
+                break;
+            if (e == INVALID_CODE)
+                return 1;
+
+            e &= 31;
+            NeedBits(e);
+
+            tabOffset = (int)(~bitBuffer & mask_bits[e]);
+            huftPointer = huftPointer.ChildNodes[tabOffset];
+        }
+
+        return 0;
+    }
+
+    private void explode_var_init()
+    {
+        /* explode the coded data */
+        bitBuffer = 0;
+        bitBufferCount = 0;
+        maskForLiteralCodeTable = mask_bits[bitsForLiteralCodeTable]; //only used in explode_lit
+        maskForLengthCodeTable = mask_bits[bitsForLengthCodeTable];
+        maskForDistanceCodeTable = mask_bits[bitsForDistanceCodeTable];
+        maskForDistanceLowBits = mask_bits[numOfUncodedLowerDistanceBits];
+        outBytesCount = 0;
+
+        windowIndex = 0; /* initialize bit buffer, window */
+    }
+
+    public override int Read(byte[] buffer, int offset, int count)
+    {
+        int countIndex = 0;
+        while (countIndex < count && outBytesCount < unCompressedSize) /* do until unCompressedSize bytes uncompressed */
+        {
+            if (length == 0)
+            {
+                NeedBits(1);
+                bool literal = (bitBuffer & 1) == 1;
+                DumpBits(1);
+
+                huftNode huftPointer;
+                if (literal) /* then literal--decode it */
+                {
+                    byte nextByte;
+                    if (hufLiteralCodeTable != null)
+                    {
+                        /* get coded literal */
+                        if (
+                            DecodeHuft(
+                                hufLiteralCodeTable,
+                                bitsForLiteralCodeTable,
+                                maskForLiteralCodeTable,
+                                out huftPointer,
+                                out _
+                            ) != 0
+                        )
+                            throw new Exception("Error decoding literal value");
+
+                        nextByte = (byte)huftPointer.Value;
+                    }
+                    else
+                    {
+                        NeedBits(8);
+                        nextByte = (byte)bitBuffer;
+                        DumpBits(8);
+                    }
+
+                    buffer[offset + (countIndex++)] = nextByte;
+                    windowsBuffer[windowIndex++] = nextByte;
+                    outBytesCount++;
+
+                    if (windowIndex == WSIZE)
+                        windowIndex = 0;
+
+                    continue;
+                }
+
+                NeedBits(numOfUncodedLowerDistanceBits); /* get distance low bits */
+                distance = (int)(bitBuffer & maskForDistanceLowBits);
+                DumpBits(numOfUncodedLowerDistanceBits);
+
+                /* get coded distance high bits */
+                if (
+                    DecodeHuft(
+                        hufDistanceCodeTable,
+                        bitsForDistanceCodeTable,
+                        maskForDistanceCodeTable,
+                        out huftPointer,
+                        out _
+                    ) != 0
+                )
+                    throw new Exception("Error decoding distance high bits");
+
+                distance = windowIndex - (distance + huftPointer.Value); /* construct offset */
+
+                /* get coded length */
+                if (
+                    DecodeHuft(
+                        hufLengthCodeTable,
+                        bitsForLengthCodeTable,
+                        maskForLengthCodeTable,
+                        out huftPointer,
+                        out int extraBitLength
+                    ) != 0
+                )
+                    throw new Exception("Error decoding coded length");
+
+                length = huftPointer.Value;
+
+                if (extraBitLength != 0) /* get length extra bits */
+                {
+                    NeedBits(8);
+                    length += (int)(bitBuffer & 0xff);
+                    DumpBits(8);
+                }
+
+                if (length > (unCompressedSize - outBytesCount))
+                    length = (int)(unCompressedSize - outBytesCount);
+
+                distance &= WSIZE - 1;
+            }
+
+            while (length != 0 && countIndex < count)
+            {
+                byte nextByte = windowsBuffer[distance++];
+                buffer[offset + (countIndex++)] = nextByte;
+                windowsBuffer[windowIndex++] = nextByte;
+                outBytesCount++;
+
+                if (distance == WSIZE)
+                    distance = 0;
+
+                if (windowIndex == WSIZE)
+                    windowIndex = 0;
+
+                length--;
+            }
+        }
+
+        return countIndex;
+    }
+}

src/SharpCompress/Compressors/Explode/HuftTree.cs

@@ -0,0 +1,269 @@
+/*
+ * This code has been converted to C# based on the original huft_tree code found in
+ * inflate.c -- by Mark Adler version c17e, 30 Mar 2007
+ */
+
+namespace SharpCompress.Compressors.Explode;
+
+public class huftNode
+{
+    public int NumberOfExtraBits; /* number of extra bits or operation */
+    public int NumberOfBitsUsed; /* number of bits in this code or subcode */
+    public int Value; /* literal, length base, or distance base */
+    public huftNode[] ChildNodes = []; /* next level of table */
+}
+
+public static class HuftTree
+{
+    private const int INVALID_CODE = 99;
+
+    /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
+    private const int BMAX = 16; /* maximum bit length of any code (16 for explode) */
+    private const int N_MAX = 288; /* maximum number of codes in any set */
+
+    public static int huftbuid(
+        int[] arrBitLengthForCodes,
+        int numberOfCodes,
+        int numberOfSimpleValueCodes,
+        int[] arrBaseValuesForNonSimpleCodes,
+        int[] arrExtraBitsForNonSimpleCodes,
+        out huftNode[] outHufTable,
+        ref int outBitsForTable
+    )
+    /* Given a list of code lengths and a maximum table size, make a set of
+    tables to decode that set of codes. Return zero on success, one if
+    the given code set is incomplete (the tables are still built in this
+    case), two if the input is invalid (all zero length codes or an
+    oversubscribed set of lengths), and three if not enough memory.
+    The code with value 256 is special, and the tables are constructed
+    so that no bits beyond that code are fetched when that code is
+    decoded. */
+    {
+        outHufTable = [];
+
+        /* Generate counts for each bit length */
+        int lengthOfEOBcode = numberOfCodes > 256 ? arrBitLengthForCodes[256] : BMAX; /* set length of EOB code, if any */
+
+        int[] arrBitLengthCount = new int[BMAX + 1];
+        for (int i = 0; i < BMAX + 1; i++)
+            arrBitLengthCount[i] = 0;
+
+        int pIndex = 0;
+        int counterCurrentCode = numberOfCodes;
+        do
+        {
+            arrBitLengthCount[arrBitLengthForCodes[pIndex]]++;
+            pIndex++; /* assume all entries <= BMAX */
+        } while ((--counterCurrentCode) != 0);
+
+        if (arrBitLengthCount[0] == numberOfCodes) /* null input--all zero length codes */
+        {
+            return 0;
+        }
+
+        /* Find minimum and maximum length, bound *outBitsForTable by those */
+        int counter;
+        for (counter = 1; counter <= BMAX; counter++)
+            if (arrBitLengthCount[counter] != 0)
+                break;
+
+        int numberOfBitsInCurrentCode = counter; /* minimum code length */
+        if (outBitsForTable < counter)
+            outBitsForTable = counter;
+
+        for (counterCurrentCode = BMAX; counterCurrentCode != 0; counterCurrentCode--)
+            if (arrBitLengthCount[counterCurrentCode] != 0)
+                break;
+
+        int maximumCodeLength = counterCurrentCode; /* maximum code length */
+        if (outBitsForTable > counterCurrentCode)
+            outBitsForTable = counterCurrentCode;
+
+        /* Adjust last length count to fill out codes, if needed */
+        int numberOfDummyCodesAdded;
+        for (
+            numberOfDummyCodesAdded = 1 << counter;
+            counter < counterCurrentCode;
+            counter++, numberOfDummyCodesAdded <<= 1
+        )
+            if ((numberOfDummyCodesAdded -= arrBitLengthCount[counter]) < 0)
+                return 2; /* bad input: more codes than bits */
+
+        if ((numberOfDummyCodesAdded -= arrBitLengthCount[counterCurrentCode]) < 0)
+            return 2;
+
+        arrBitLengthCount[counterCurrentCode] += numberOfDummyCodesAdded;
+
+        /* Generate starting offsets into the value table for each length */
+        int[] bitOffset = new int[BMAX + 1];
+        bitOffset[1] = 0;
+        counter = 0;
+        pIndex = 1;
+        int xIndex = 2;
+        while ((--counterCurrentCode) != 0)
+        { /* note that i == g from above */
+            bitOffset[xIndex++] = (counter += arrBitLengthCount[pIndex++]);
+        }
+
+        /* Make a table of values in order of bit lengths */
+        int[] arrValuesInOrderOfBitLength = new int[N_MAX];
+        for (int i = 0; i < N_MAX; i++)
+            arrValuesInOrderOfBitLength[i] = 0;
+
+        pIndex = 0;
+        counterCurrentCode = 0;
+        do
+        {
+            if ((counter = arrBitLengthForCodes[pIndex++]) != 0)
+                arrValuesInOrderOfBitLength[bitOffset[counter]++] = counterCurrentCode;
+        } while (++counterCurrentCode < numberOfCodes);
+
+        numberOfCodes = bitOffset[maximumCodeLength]; /* set numberOfCodes to length of v */
+
+        /* Generate the Huffman codes and for each, make the table entries */
+        bitOffset[0] = counterCurrentCode = 0; /* first Huffman code is zero */
+        pIndex = 0; /* grab values in bit order */
+        int tableLevel = -1; /* no tables yet--level -1 */
+        int bitsBeforeThisTable = 0;
+        int[] arrLX = new int[BMAX + 1];
+        int stackOfBitsPerTable = 1; /* stack of bits per table */
+        arrLX[stackOfBitsPerTable - 1] = 0; /* no bits decoded yet */
+
+        huftNode[][] arrHufTableStack = new huftNode[BMAX][];
+        huftNode[] pointerToCurrentTable = [];
+        int numberOfEntriesInCurrentTable = 0;
+
+        bool first = true;
+
+        /* go through the bit lengths (k already is bits in shortest code) */
+        for (; numberOfBitsInCurrentCode <= maximumCodeLength; numberOfBitsInCurrentCode++)
+        {
+            int counterForCodes = arrBitLengthCount[numberOfBitsInCurrentCode];
+            while ((counterForCodes--) != 0)
+            {
+                /* here i is the Huffman code of length k bits for value *p */
+                /* make tables up to required level */
+                while (
+                    numberOfBitsInCurrentCode
+                    > bitsBeforeThisTable + arrLX[stackOfBitsPerTable + tableLevel]
+                )
+                {
+                    bitsBeforeThisTable += arrLX[stackOfBitsPerTable + (tableLevel++)]; /* add bits already decoded */
+
+                    /* compute minimum size table less than or equal to *outBitsForTable bits */
+                    numberOfEntriesInCurrentTable =
+                        (numberOfEntriesInCurrentTable = maximumCodeLength - bitsBeforeThisTable)
+                        > outBitsForTable
+                            ? outBitsForTable
+                            : numberOfEntriesInCurrentTable; /* upper limit */
+                    int fBitCounter1 =
+                        1 << (counter = numberOfBitsInCurrentCode - bitsBeforeThisTable);
+                    if (fBitCounter1 > counterForCodes + 1) /* try a k-w bit table */
+                    { /* too few codes for k-w bit table */
+                        fBitCounter1 -= counterForCodes + 1; /* deduct codes from patterns left */
+                        xIndex = numberOfBitsInCurrentCode;
+                        while (++counter < numberOfEntriesInCurrentTable) /* try smaller tables up to z bits */
+                        {
+                            if ((fBitCounter1 <<= 1) <= arrBitLengthCount[++xIndex])
+                                break; /* enough codes to use up j bits */
+                            fBitCounter1 -= arrBitLengthCount[xIndex]; /* else deduct codes from patterns */
+                        }
+                    }
+                    if (
+                        bitsBeforeThisTable + counter > lengthOfEOBcode
+                        && bitsBeforeThisTable < lengthOfEOBcode
+                    )
+                        counter = lengthOfEOBcode - bitsBeforeThisTable; /* make EOB code end at table */
+
+                    numberOfEntriesInCurrentTable = 1 << counter; /* table entries for j-bit table */
+                    arrLX[stackOfBitsPerTable + tableLevel] = counter; /* set table size in stack */
+
+                    /* allocate and link in new table */
+                    pointerToCurrentTable = new huftNode[numberOfEntriesInCurrentTable];
+
+                    // set the pointer, pointed to by *outHufTable to the second huft in pointertoCurrentTable
+                    if (first)
+                    {
+                        outHufTable = pointerToCurrentTable; /* link to list for huft_free() */
+                        first = false;
+                    }
+
+                    arrHufTableStack[tableLevel] = pointerToCurrentTable; /* table starts after link */
+
+                    /* connect to last table, if there is one */
+                    if (tableLevel != 0)
+                    {
+                        bitOffset[tableLevel] = counterCurrentCode; /* save pattern for backing up */
+
+                        huftNode vHuft = new huftNode
+                        {
+                            NumberOfBitsUsed = arrLX[stackOfBitsPerTable + tableLevel - 1], /* bits to dump before this table */
+                            NumberOfExtraBits = 32 + counter, /* bits in this table */
+                            ChildNodes = pointerToCurrentTable, /* pointer to this table */
+                        };
+
+                        counter =
+                            (counterCurrentCode & ((1 << bitsBeforeThisTable) - 1))
+                            >> (bitsBeforeThisTable - arrLX[stackOfBitsPerTable + tableLevel - 1]);
+                        arrHufTableStack[tableLevel - 1][counter] = vHuft; /* connect to last table */
+                    }
+                }
+
+                /* set up table entry in r */
+                huftNode vHuft1 = new huftNode
+                {
+                    NumberOfBitsUsed = numberOfBitsInCurrentCode - bitsBeforeThisTable,
+                };
+
+                if (pIndex >= numberOfCodes)
+                    vHuft1.NumberOfExtraBits = INVALID_CODE; /* out of values--invalid code */
+                else if (arrValuesInOrderOfBitLength[pIndex] < numberOfSimpleValueCodes)
+                {
+                    vHuft1.NumberOfExtraBits = (
+                        arrValuesInOrderOfBitLength[pIndex] < 256 ? 32 : 31
+                    ); /* 256 is end-of-block code */
+                    vHuft1.Value = arrValuesInOrderOfBitLength[pIndex++]; /* simple code is just the value */
+                }
+                else
+                {
+                    vHuft1.NumberOfExtraBits = arrExtraBitsForNonSimpleCodes[
+                        arrValuesInOrderOfBitLength[pIndex] - numberOfSimpleValueCodes
+                    ]; /* non-simple--look up in lists */
+                    vHuft1.Value = arrBaseValuesForNonSimpleCodes[
+                        arrValuesInOrderOfBitLength[pIndex++] - numberOfSimpleValueCodes
+                    ];
+                }
+
+                /* fill code-like entries with r */
+                int fBitCounter2 = 1 << (numberOfBitsInCurrentCode - bitsBeforeThisTable);
+                for (
+                    counter = counterCurrentCode >> bitsBeforeThisTable;
+                    counter < numberOfEntriesInCurrentTable;
+                    counter += fBitCounter2
+                )
+                    pointerToCurrentTable[counter] = vHuft1;
+
+                /* backwards increment the k-bit code i */
+                for (
+                    counter = 1 << (numberOfBitsInCurrentCode - 1);
+                    (counterCurrentCode & counter) != 0;
+                    counter >>= 1
+                )
+                    counterCurrentCode ^= counter;
+                counterCurrentCode ^= counter;
+
+                /* backup over finished tables */
+                while (
+                    (counterCurrentCode & ((1 << bitsBeforeThisTable) - 1)) != bitOffset[tableLevel]
+                )
+                    bitsBeforeThisTable -= arrLX[stackOfBitsPerTable + (--tableLevel)];
+            }
+        }
+
+        /* return actual size of base table */
+        outBitsForTable = arrLX[stackOfBitsPerTable];
+
+        /* Return true (1) if we were given an incomplete table */
+        return (numberOfDummyCodesAdded != 0 && maximumCodeLength != 1) ? 1 : 0;
+    }
+}

src/SharpCompress/Compressors/Filters/BCJFilter.cs

@@ -13,7 +13,7 @@ internal class BCJFilter : Filter
         true,
         false,
         false,
-        false
+        false,
     };
 
     private static readonly int[] MASK_TO_BIT_NUMBER = { 0, 1, 2, 2, 3, 3, 3, 3 };

src/SharpCompress/Compressors/Filters/BCJFilterARM64.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Buffers.Binary;
+using System.IO;
+
+namespace SharpCompress.Compressors.Filters;
+
+internal class BCJFilterARM64 : Filter
+{
+    private int _pos;
+
+    public BCJFilterARM64(bool isEncoder, Stream baseStream)
+        : base(isEncoder, baseStream, 8) => _pos = 0;
+
+    protected override int Transform(byte[] buffer, int offset, int count)
+    {
+        var end = offset + count - 4;
+        int i;
+
+        for (i = offset; i <= end; i += 4)
+        {
+            uint pc = (uint)(_pos + i - offset);
+            uint instr = BinaryPrimitives.ReadUInt32LittleEndian(
+                new ReadOnlySpan<byte>(buffer, i, 4)
+            );
+
+            if ((instr >> 26) == 0x25)
+            {
+                uint src = instr;
+                instr = 0x94000000;
+
+                pc >>= 2;
+                if (!_isEncoder)
+                    pc = 0U - pc;
+
+                instr |= (src + pc) & 0x03FFFFFF;
+                BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i, 4), instr);
+            }
+            else if ((instr & 0x9F000000) == 0x90000000)
+            {
+                uint src = ((instr >> 29) & 3) | ((instr >> 3) & 0x001FFFFC);
+
+                if (((src + 0x00020000) & 0x001C0000) != 0)
+                    continue;
+
+                instr &= 0x9000001F;
+
+                pc >>= 12;
+                if (!_isEncoder)
+                    pc = 0U - pc;
+
+                uint dest = src + pc;
+                instr |= (dest & 3) << 29;
+                instr |= (dest & 0x0003FFFC) << 3;
+                instr |= (0U - (dest & 0x00020000)) & 0x00E00000;
+                BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i, 4), instr);
+            }
+        }
+
+        i -= offset;
+        _pos += i;
+        return i;
+    }
+}

src/SharpCompress/Compressors/Filters/BCJFilterIA64.cs

@@ -39,7 +39,7 @@ internal class BCJFilterIA64 : Filter
         4,
         4,
         0,
-        0
+        0,
     };
 
     public BCJFilterIA64(bool isEncoder, Stream baseStream)

src/SharpCompress/Compressors/Filters/BCJFilterRISCV.cs

@@ -0,0 +1,210 @@
+using System;
+using System.Buffers.Binary;
+using System.IO;
+
+namespace SharpCompress.Compressors.Filters;
+
+internal class BCJFilterRISCV : Filter
+{
+    private int _pos;
+
+    public BCJFilterRISCV(bool isEncoder, Stream baseStream)
+        : base(isEncoder, baseStream, 8) => _pos = 0;
+
+    private int Decode(byte[] buffer, int offset, int count)
+    {
+        if (count < 8)
+        {
+            return 0;
+        }
+
+        var end = offset + count - 8;
+        int i;
+        for (i = offset; i <= end; i += 2)
+        {
+            uint inst = buffer[i];
+            if (inst == 0xEF)
+            {
+                uint b1 = buffer[i + 1];
+                if ((b1 & 0x0D) != 0)
+                    continue;
+
+                uint b2 = buffer[i + 2];
+                uint b3 = buffer[i + 3];
+                uint pc = (uint)(_pos + i);
+
+                uint addr = ((b1 & 0xF0) << 13) | (b2 << 9) | (b3 << 1);
+
+                addr -= pc;
+
+                buffer[i + 1] = (byte)((b1 & 0x0F) | ((addr >> 8) & 0xF0));
+
+                buffer[i + 2] = (byte)(
+                    ((addr >> 16) & 0x0F) | ((addr >> 7) & 0x10) | ((addr << 4) & 0xE0)
+                );
+
+                buffer[i + 3] = (byte)(((addr >> 4) & 0x7F) | ((addr >> 13) & 0x80));
+
+                i += 4 - 2;
+            }
+            else if ((inst & 0x7F) == 0x17)
+            {
+                uint inst2 = 0;
+                inst |= (uint)buffer[i + 1] << 8;
+                inst |= (uint)buffer[i + 2] << 16;
+                inst |= (uint)buffer[i + 3] << 24;
+
+                if ((inst & 0xE80) != 0)
+                {
+                    inst2 = BinaryPrimitives.ReadUInt32LittleEndian(
+                        new ReadOnlySpan<byte>(buffer, i + 4, 4)
+                    );
+                    if (((((inst) << 8) ^ (inst2)) & 0xF8003) != 3)
+                    {
+                        i += 6 - 2;
+                        continue;
+                    }
+                    uint addr = inst & 0xFFFFF000;
+                    addr += inst2 >> 20;
+
+                    inst = 0x17 | (2 << 7) | (inst2 << 12);
+                    inst2 = addr;
+                }
+                else
+                {
+                    uint inst2_rs1 = inst >> 27;
+                    if ((uint)(((inst) - 0x3117) << 18) >= ((inst2_rs1) & 0x1D))
+                    {
+                        i += 4 - 2;
+                        continue;
+                    }
+
+                    uint addr = BinaryPrimitives.ReadUInt32BigEndian(
+                        new ReadOnlySpan<byte>(buffer, i + 4, 4)
+                    );
+
+                    addr -= (uint)(_pos + i);
+
+                    inst2 = (inst >> 12) | (addr << 20);
+
+                    inst = 0x17 | (inst2_rs1 << 7) | ((addr + 0x800) & 0xFFFFF000);
+                }
+                BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i, 4), inst);
+                BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i + 4, 4), inst2);
+
+                i += 8 - 2;
+            }
+        }
+        i -= offset;
+        _pos += i;
+        return i;
+    }
+
+    private int Encode(byte[] buffer, int offset, int count)
+    {
+        if (count < 8)
+        {
+            return 0;
+        }
+
+        var end = offset + count - 8;
+        int i;
+        for (i = offset; i <= end; i += 2)
+        {
+            uint inst = buffer[i];
+            if (inst == 0xEF)
+            {
+                uint b1 = buffer[i + 1];
+                if ((b1 & 0x0D) != 0)
+                    continue;
+
+                uint b2 = buffer[i + 2];
+                uint b3 = buffer[i + 3];
+                uint pc = (uint)(_pos + i);
+
+                uint addr =
+                    ((b1 & 0xF0) << 8)
+                    | ((b2 & 0x0F) << 16)
+                    | ((b2 & 0x10) << 7)
+                    | ((b2 & 0xE0) >> 4)
+                    | ((b3 & 0x7F) << 4)
+                    | ((b3 & 0x80) << 13);
+
+                addr += pc;
+
+                buffer[i + 1] = (byte)((b1 & 0x0F) | ((addr >> 13) & 0xF0));
+
+                buffer[i + 2] = (byte)(addr >> 9);
+
+                buffer[i + 3] = (byte)(addr >> 1);
+
+                i += 4 - 2;
+            }
+            else if ((inst & 0x7F) == 0x17)
+            {
+                inst |= (uint)buffer[i + 1] << 8;
+                inst |= (uint)buffer[i + 2] << 16;
+                inst |= (uint)buffer[i + 3] << 24;
+
+                if ((inst & 0xE80) != 0)
+                {
+                    uint inst2 = BinaryPrimitives.ReadUInt32LittleEndian(
+                        new ReadOnlySpan<byte>(buffer, i + 4, 4)
+                    );
+                    if (((((inst) << 8) ^ (inst2)) & 0xF8003) != 3)
+                    {
+                        i += 6 - 2;
+                        continue;
+                    }
+                    uint addr = inst & 0xFFFFF000;
+                    addr += (inst2 >> 20) - ((inst2 >> 19) & 0x1000);
+
+                    addr += (uint)(_pos + i);
+                    inst = 0x17 | (2 << 7) | (inst2 << 12);
+
+                    BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i, 4), inst);
+                    BinaryPrimitives.WriteUInt32BigEndian(new Span<byte>(buffer, i + 4, 4), addr);
+                }
+                else
+                {
+                    uint fake_rs1 = inst >> 27;
+                    if ((uint)(((inst) - 0x3117) << 18) >= ((fake_rs1) & 0x1D))
+                    {
+                        i += 4 - 2;
+                        continue;
+                    }
+
+                    uint fake_addr = BinaryPrimitives.ReadUInt32LittleEndian(
+                        new ReadOnlySpan<byte>(buffer, i + 4, 4)
+                    );
+
+                    uint fake_inst2 = (inst >> 12) | (fake_addr << 20);
+
+                    inst = 0x17 | (fake_rs1 << 7) | (fake_addr & 0xFFFFF000);
+
+                    BinaryPrimitives.WriteUInt32LittleEndian(new Span<byte>(buffer, i, 4), inst);
+                    BinaryPrimitives.WriteUInt32LittleEndian(
+                        new Span<byte>(buffer, i + 4, 4),
+                        fake_inst2
+                    );
+                }
+                i += 8 - 2;
+            }
+        }
+        i -= offset;
+        _pos += i;
+        return i;
+    }
+
+    protected override int Transform(byte[] buffer, int offset, int count)
+    {
+        if (_isEncoder)
+        {
+            return Encode(buffer, offset, count);
+        }
+        else
+        {
+            return Decode(buffer, offset, count);
+        }
+    }
+}

src/SharpCompress/Compressors/LZMA/AesDecoderStream.cs

@@ -20,7 +20,8 @@ internal sealed class AesDecoderStream : DecoderStream2
 
     public AesDecoderStream(Stream input, byte[] info, IPasswordProvider pass, long limit)
     {
-        if (pass.CryptoGetTextPassword() == null)
+        var password = pass.CryptoGetTextPassword();
+        if (password == null)
         {
             throw new SharpCompress.Common.CryptographicException(
                 "Encrypted 7Zip archive has no password specified."
@@ -37,8 +38,8 @@ internal sealed class AesDecoderStream : DecoderStream2
 
         Init(info, out var numCyclesPower, out var salt, out var seed);
 
-        var password = Encoding.Unicode.GetBytes(pass.CryptoGetTextPassword());
-        var key = InitKey(numCyclesPower, salt, password);
+        var passwordBytes = Encoding.Unicode.GetBytes(password);
+        var key = InitKey(numCyclesPower, salt, passwordBytes);
         if (key == null)
         {
             throw new InvalidOperationException("Initialized with null key");
@@ -207,28 +208,6 @@ internal sealed class AesDecoderStream : DecoderStream2
         }
         else
         {
-#if NETSTANDARD2_0
-            using var sha = IncrementalHash.CreateHash(HashAlgorithmName.SHA256);
-            var counter = new byte[8];
-            var numRounds = 1L << mNumCyclesPower;
-            for (long round = 0; round < numRounds; round++)
-            {
-                sha.AppendData(salt, 0, salt.Length);
-                sha.AppendData(pass, 0, pass.Length);
-                sha.AppendData(counter, 0, 8);
-
-                // This mirrors the counter so we don't have to convert long to byte[] each round.
-                // (It also ensures the counter is little endian, which BitConverter does not.)
-                for (var i = 0; i < 8; i++)
-                {
-                    if (++counter[i] != 0)
-                    {
-                        break;
-                    }
-                }
-            }
-            return sha.GetHashAndReset();
-#else
             using var sha = SHA256.Create();
             var counter = new byte[8];
             var numRounds = 1L << mNumCyclesPower;
@@ -251,7 +230,6 @@ internal sealed class AesDecoderStream : DecoderStream2
 
             sha.TransformFinalBlock(counter, 0, 0);
             return sha.Hash;
-#endif
         }
     }