Mark for 0.18.1

* Don't skip ZipReader data twice.

* Add archive for a new test

.travis.yml

@@ -0,0 +1,13 @@
+dist: trusty
+language: csharp
+cache:
+  directories:
+  - $HOME/.dotnet
+solution: SharpCompress.sln
+matrix:
+  include:
+    - dotnet: 1.0.4
+      mono: none
+      env: DOTNETCORE=1
+script:
+  - ./build.sh

FORMATS.md

@@ -1,10 +1,10 @@
-# Archive Formats
+# Formats
 
 ## Accessing Archives
 
-Archive classes allow random access to a seekable stream.
-Reader classes allow forward-only reading
-Writer classes allow forward-only Writing
+- Archive classes allow random access to a seekable stream.
+- Reader classes allow forward-only reading on a stream.
+- Writer classes allow forward-only Writing on a stream.
 
 ## Supported Format Table
 
@@ -12,18 +12,24 @@ Writer classes allow forward-only Writing
 | --- | --- | --- | --- | --- | --- |
 | Rar | Rar | Decompress (1) | RarArchive | RarReader | N/A |
 | Zip (2) | None, DEFLATE, BZip2, LZMA/LZMA2, PPMd | Both | ZipArchive | ZipReader | ZipWriter |
-| Tar | None, BZip2, GZip, LZip | Both | TarArchive | TarReader | TarWriter (3)  |
-| GZip (single file) | GZip | Both | GZipArchive | GZipReader | GZipWriter |
+| Tar | None | Both | TarArchive | TarReader | TarWriter (3)  |
+| Tar.GZip | DEFLATE | Both | TarArchive | TarReader | TarWriter (3)  |
+| Tar.BZip2 | BZip2 | Both | TarArchive | TarReader | TarWriter (3)  |
+| Tar.LZip | LZMA | Both | TarArchive | TarReader | TarWriter (3)  |
+| Tar.XZ | LZMA2 | Decompress | TarArchive | TarReader | TarWriter (3)  |
+| GZip (single file) | DEFLATE | Both | GZipArchive | GZipReader | GZipWriter |
 | 7Zip (4) | LZMA, LZMA2, BZip2, PPMd, BCJ, BCJ2, Deflate | Decompress | SevenZipArchive | N/A | N/A |
+| LZip (single file) (5) | LZip (LZMA) | Both | LZipArchive | LZipReader | LZipWriter |
 
  1. SOLID Rars are only supported in the RarReader API.
- 2. Zip format supports pkware and WinzipAES encryption.  However, encrypted LZMA is not supported.  Zip64 reading is supported.
+ 2. Zip format supports pkware and WinzipAES encryption.  However, encrypted LZMA is not supported.  Zip64 reading/writing is supported but only with seekable streams as the Zip spec doesn't support Zip64 data in post data descriptors.
  3. The Tar format requires a file size in the header.  If no size is specified to the TarWriter and the stream is not seekable, then an exception will be thrown.
  4. The 7Zip format doesn't allow for reading as a forward-only stream so 7Zip is only supported through the Archive API
+ 5. LZip has no support for extra data like the file name or timestamp.  There is a default filename used when looking at the entry Key on the archive.
 
-## Compressors
+## Compression Streams
 
-For those who want to directly compress/decompress bits
+For those who want to directly compress/decompress bits.  The single file formats are represented here as well.  However, BZip2, LZip and XZ have no metadata (GZip has a little) so using them without something like a Tar file makes little sense.
 
 | Compressor | Compress/Decompress |
 | --- | --- |
@@ -33,4 +39,22 @@ For those who want to directly compress/decompress bits
 | LZMAStream | Both |
 | PPMdStream | Both |
 | ADCStream | Decompress |
-| LZipStream | Decompress |
+| LZipStream | Both |
+| XZStream | Decompress |
+
+## Archive Formats vs Compression 
+
+Sometimes the terminology gets mixed.
+
+### Compression
+
+DEFLATE, LZMA are pure compression algorithms
+
+### Formats
+
+Formats like Zip, 7Zip, Rar are archive formats only.  They use other compression methods (e.g. DEFLATE, LZMA, etc.) or propriatory (e.g RAR)
+
+### Overlap
+
+GZip, BZip2 and LZip are single file archival formats.  The overlap in the API happens because Tar uses the single file formats as "compression" methods and the API tries to hide this a bit.
+

README.md

@@ -1,16 +1,30 @@
 # SharpCompress
 
-SharpCompress is a compression library for .NET/Mono/Silverlight/WP7 that can unrar, un7zip, unzip, untar unbzip2 and ungzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip are implemented.
+SharpCompress is a compression library in pure C# for .NET 3.5, 4.5, .NET Standard 1.0, 1.3 that can unrar, un7zip, unzip, untar unbzip2 and ungzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip are implemented.
 
 The major feature is support for non-seekable streams so large files can be processed on the fly (i.e. download stream). 
 
+AppVeyor Build - 
 [![Build status](https://ci.appveyor.com/api/projects/status/voxg971oemmvxh1e/branch/master?svg=true)](https://ci.appveyor.com/project/adamhathcock/sharpcompress/branch/master)
 
+Travis CI Build - 
+[![Build Status](https://travis-ci.org/adamhathcock/sharpcompress.svg?branch=master)](https://travis-ci.org/adamhathcock/sharpcompress)
+
 ## Need Help?
 Post Issues on Github!
 
 Check the [Supported Formats](FORMATS.md) and [Basic Usage.](USAGE.md)
 
+## Recommended Formats
+
+In general, I recommend GZip (Deflate)/BZip2 (BZip)/LZip (LZMA) as the simplicity of the formats lend to better long term archival as well as the streamability.  Tar is often used in conjunction for multiple files in a single archive (e.g. `.tar.gz`)
+
+Zip is okay, but it's a very hap-hazard format and the variation in headers and implementations makes it hard to get correct.  Uses Deflate by default but supports a lot of compression methods.
+
+RAR is not recommended as it's a propriatory format and the compression is closed source.  Use Tar/LZip for LZMA
+
+7Zip and XZ both are overly complicated.  7Zip does not support streamable formats.  XZ has known holes explained here: (http://www.nongnu.org/lzip/xz_inadequate.html)  Use Tar/LZip for LZMA compression instead.
+
 ## A Simple Request
 
 Hi everyone. I hope you're using SharpCompress and finding it useful. Please give me feedback on what you'd like to see changed especially as far as usability goes. New feature suggestions are always welcome as well. I would also like to know what projects SharpCompress is being used in. I like seeing how it is used to give me ideas for future versions. Thanks!
@@ -27,10 +41,43 @@ I'm always looking for help or ideas. Please submit code or email with ideas. Un
 * 7Zip writing
 * Zip64 (Need writing and extend Reading)
 * Multi-volume Zip support.
-* RAR5 support
 
 ## Version Log
 
+### Version 0.18
+
+* [Now on Github releases](https://github.com/adamhathcock/sharpcompress/releases/tag/0.18)
+
+### Version 0.17.1
+
+* Fix - [Bug Fix for .NET Core on Windows](https://github.com/adamhathcock/sharpcompress/pull/257)
+
+### Version 0.17.0
+
+* New - Full LZip support!  Can read and write LZip files and Tars inside LZip files.  [Make LZip a first class citizen. #241](https://github.com/adamhathcock/sharpcompress/issues/241)
+* New - XZ read support!  Can read XZ files and Tars inside XZ files.  [XZ in SharpCompress #91](https://github.com/adamhathcock/sharpcompress/issues/94)
+* Fix - [Regression - zip file writing on seekable streams always assumed stream start was 0.  Introduced with Zip64 writing.](https://github.com/adamhathcock/sharpcompress/issues/244)
+* Fix - [Zip files with post-data descriptors can be properly skipped via decompression](https://github.com/adamhathcock/sharpcompress/issues/162)
+
+### Version 0.16.2
+
+* Fix [.NET 3.5 should support files and cryptography (was a regression from 0.16.0)](https://github.com/adamhathcock/sharpcompress/pull/251)
+* Fix [Zip per entry compression customization wrote the wrong method into the zip archive](https://github.com/adamhathcock/sharpcompress/pull/249)
+
+### Version 0.16.1
+
+* Fix [Preserve compression method when getting a compressed stream](https://github.com/adamhathcock/sharpcompress/pull/235)
+* Fix [RAR entry key normalization fix](https://github.com/adamhathcock/sharpcompress/issues/201)
+
+### Version 0.16.0
+
+* Breaking - [Progress Event Tracking rethink](https://github.com/adamhathcock/sharpcompress/pull/226)
+* Update to VS2017 - [VS2017](https://github.com/adamhathcock/sharpcompress/pull/231) - Framework targets have been changed.
+* New - [Add Zip64 writing](https://github.com/adamhathcock/sharpcompress/pull/211)
+* [Fix invalid/mismatching Zip version flags.](https://github.com/adamhathcock/sharpcompress/issues/164) - This allows nuget/System.IO.Packaging to read zip files generated by SharpCompress
+* [Fix 7Zip directory hiding](https://github.com/adamhathcock/sharpcompress/pull/215/files)
+* [Verify RAR CRC headers](https://github.com/adamhathcock/sharpcompress/pull/220)
+
 ### Version 0.15.2
 
 * [Fix invalid headers](https://github.com/adamhathcock/sharpcompress/pull/210) - fixes an issue creating large-ish zip archives that was introduced with zip64 reading.
@@ -135,6 +182,8 @@ I'm always looking for help or ideas. Please submit code or email with ideas. Un
 * Embedded some BouncyCastle crypto classes to allow RAR Decryption and Winzip AES Decryption in Portable and Windows Store DLLs
 * Built in Release (I think)
 
+XZ implementation based on: https://github.com/sambott/XZ.NET by @sambott
+
 7Zip implementation based on: https://code.google.com/p/managed-lzma/
 
 LICENSE

appveyor.yml

@@ -11,18 +11,10 @@ branches:
 nuget:
   disable_publish_on_pr: true
 
-before_build:
-  - cmd: dotnet restore
+build_script:
+- ps: .\build.ps1
 
-build:
-  parallel: true
-  verbosity: minimal
-
-after_build:
-- dotnet pack "src\SharpCompress\SharpCompress.csproj" -c Release
-
-test_script:
-- dotnet test --no-build .\tests\SharpCompress.Test\SharpCompress.Test.csproj
+test: off
 
 artifacts:
 - path: src\SharpCompress\bin\Release\*.nupkg

build.cake

@@ -0,0 +1,93 @@
+var target = Argument("target", "Default");
+var tag = Argument("tag", "cake");
+
+Task("Restore")
+  .Does(() =>
+{
+    DotNetCoreRestore(".");
+});
+
+Task("Build")
+  .IsDependentOn("Restore")
+  .Does(() =>
+{
+    if (IsRunningOnWindows())
+    {
+        MSBuild("./sharpcompress.sln", c => 
+        { 
+            c.SetConfiguration("Release")
+            .SetVerbosity(Verbosity.Minimal)
+            .UseToolVersion(MSBuildToolVersion.VS2017);
+        });
+    }
+    else 
+    {
+        var settings = new DotNetCoreBuildSettings
+        {
+            Framework = "netstandard1.0",
+            Configuration = "Release"
+        };
+
+        DotNetCoreBuild("./src/SharpCompress/SharpCompress.csproj", settings);
+
+        settings.Framework = "netcoreapp1.1";
+        DotNetCoreBuild("./tests/SharpCompress.Test/SharpCompress.Test.csproj", settings);
+    }
+});
+
+Task("Test")
+  .IsDependentOn("Build")
+  .Does(() =>
+{
+    if (!bool.Parse(EnvironmentVariable("APPVEYOR") ?? "false")
+        && !bool.Parse(EnvironmentVariable("TRAVIS") ?? "false"))
+    {
+        var files = GetFiles("tests/**/*.csproj");
+        foreach(var file in files)
+        {
+            var settings = new DotNetCoreTestSettings
+            {
+                Configuration = "Release"
+            };
+
+            DotNetCoreTest(file.ToString(), settings);
+        }
+    } 
+    else 
+    {
+        Information("Skipping tests as this is AppVeyor or Travis CI");
+    }
+});
+
+Task("Pack")
+    .IsDependentOn("Build")
+    .Does(() => 
+{
+    if (IsRunningOnWindows())
+    {
+        MSBuild("src/SharpCompress/SharpCompress.csproj", c => c
+            .SetConfiguration("Release")
+            .SetVerbosity(Verbosity.Minimal)
+            .UseToolVersion(MSBuildToolVersion.VS2017)
+            .WithProperty("NoBuild", "true")
+            .WithTarget("Pack"));
+    } 
+    else 
+    {
+        Information("Skipping Pack as this is not Windows");
+    }
+});
+
+Task("Default")
+    .IsDependentOn("Restore")
+    .IsDependentOn("Build")
+    .IsDependentOn("Test")
+    .IsDependentOn("Pack");
+
+ Task("RunTests")
+    .IsDependentOn("Restore")
+    .IsDependentOn("Build")
+    .IsDependentOn("Test");
+
+
+RunTarget(target);

build.ps1

@@ -0,0 +1,228 @@
+##########################################################################
+# This is the Cake bootstrapper script for PowerShell.
+# This file was downloaded from https://github.com/cake-build/resources
+# Feel free to change this file to fit your needs.
+##########################################################################
+
+<#
+
+.SYNOPSIS
+This is a Powershell script to bootstrap a Cake build.
+
+.DESCRIPTION
+This Powershell script will download NuGet if missing, restore NuGet tools (including Cake)
+and execute your Cake build script with the parameters you provide.
+
+.PARAMETER Script
+The build script to execute.
+.PARAMETER Target
+The build script target to run.
+.PARAMETER Configuration
+The build configuration to use.
+.PARAMETER Verbosity
+Specifies the amount of information to be displayed.
+.PARAMETER Experimental
+Tells Cake to use the latest Roslyn release.
+.PARAMETER WhatIf
+Performs a dry run of the build script.
+No tasks will be executed.
+.PARAMETER Mono
+Tells Cake to use the Mono scripting engine.
+.PARAMETER SkipToolPackageRestore
+Skips restoring of packages.
+.PARAMETER ScriptArgs
+Remaining arguments are added here.
+
+.LINK
+http://cakebuild.net
+
+#>
+
+[CmdletBinding()]
+Param(
+    [string]$Script = "build.cake",
+    [string]$Target = "Default",
+    [ValidateSet("Release", "Debug")]
+    [string]$Configuration = "Release",
+    [ValidateSet("Quiet", "Minimal", "Normal", "Verbose", "Diagnostic")]
+    [string]$Verbosity = "Verbose",
+    [switch]$Experimental,
+    [Alias("DryRun","Noop")]
+    [switch]$WhatIf,
+    [switch]$Mono,
+    [switch]$SkipToolPackageRestore,
+    [Parameter(Position=0,Mandatory=$false,ValueFromRemainingArguments=$true)]
+    [string[]]$ScriptArgs
+)
+
+[Reflection.Assembly]::LoadWithPartialName("System.Security") | Out-Null
+function MD5HashFile([string] $filePath)
+{
+    if ([string]::IsNullOrEmpty($filePath) -or !(Test-Path $filePath -PathType Leaf))
+    {
+        return $null
+    }
+
+    [System.IO.Stream] $file = $null;
+    [System.Security.Cryptography.MD5] $md5 = $null;
+    try
+    {
+        $md5 = [System.Security.Cryptography.MD5]::Create()
+        $file = [System.IO.File]::OpenRead($filePath)
+        return [System.BitConverter]::ToString($md5.ComputeHash($file))
+    }
+    finally
+    {
+        if ($file -ne $null)
+        {
+            $file.Dispose()
+        }
+    }
+}
+
+Write-Host "Preparing to run build script..."
+
+if(!$PSScriptRoot){
+    $PSScriptRoot = Split-Path $MyInvocation.MyCommand.Path -Parent
+}
+
+$TOOLS_DIR = Join-Path $PSScriptRoot "tools"
+$ADDINS_DIR = Join-Path $TOOLS_DIR "addins"
+$MODULES_DIR = Join-Path $TOOLS_DIR "modules"
+$NUGET_EXE = Join-Path $TOOLS_DIR "nuget.exe"
+$CAKE_EXE = Join-Path $TOOLS_DIR "Cake/Cake.exe"
+$NUGET_URL = "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe"
+$PACKAGES_CONFIG = Join-Path $TOOLS_DIR "packages.config"
+$PACKAGES_CONFIG_MD5 = Join-Path $TOOLS_DIR "packages.config.md5sum"
+$ADDINS_PACKAGES_CONFIG = Join-Path $ADDINS_DIR "packages.config"
+$MODULES_PACKAGES_CONFIG = Join-Path $MODULES_DIR "packages.config"
+
+# Should we use mono?
+$UseMono = "";
+if($Mono.IsPresent) {
+    Write-Verbose -Message "Using the Mono based scripting engine."
+    $UseMono = "-mono"
+}
+
+# Should we use the new Roslyn?
+$UseExperimental = "";
+if($Experimental.IsPresent -and !($Mono.IsPresent)) {
+    Write-Verbose -Message "Using experimental version of Roslyn."
+    $UseExperimental = "-experimental"
+}
+
+# Is this a dry run?
+$UseDryRun = "";
+if($WhatIf.IsPresent) {
+    $UseDryRun = "-dryrun"
+}
+
+# Make sure tools folder exists
+if ((Test-Path $PSScriptRoot) -and !(Test-Path $TOOLS_DIR)) {
+    Write-Verbose -Message "Creating tools directory..."
+    New-Item -Path $TOOLS_DIR -Type directory | out-null
+}
+
+# Make sure that packages.config exist.
+if (!(Test-Path $PACKAGES_CONFIG)) {
+    Write-Verbose -Message "Downloading packages.config..."
+    try { (New-Object System.Net.WebClient).DownloadFile("http://cakebuild.net/download/bootstrapper/packages", $PACKAGES_CONFIG) } catch {
+        Throw "Could not download packages.config."
+    }
+}
+
+# Try find NuGet.exe in path if not exists
+if (!(Test-Path $NUGET_EXE)) {
+    Write-Verbose -Message "Trying to find nuget.exe in PATH..."
+    $existingPaths = $Env:Path -Split ';' | Where-Object { (![string]::IsNullOrEmpty($_)) -and (Test-Path $_ -PathType Container) }
+    $NUGET_EXE_IN_PATH = Get-ChildItem -Path $existingPaths -Filter "nuget.exe" | Select -First 1
+    if ($NUGET_EXE_IN_PATH -ne $null -and (Test-Path $NUGET_EXE_IN_PATH.FullName)) {
+        Write-Verbose -Message "Found in PATH at $($NUGET_EXE_IN_PATH.FullName)."
+        $NUGET_EXE = $NUGET_EXE_IN_PATH.FullName
+    }
+}
+
+# Try download NuGet.exe if not exists
+if (!(Test-Path $NUGET_EXE)) {
+    Write-Verbose -Message "Downloading NuGet.exe..."
+    try {
+        (New-Object System.Net.WebClient).DownloadFile($NUGET_URL, $NUGET_EXE)
+    } catch {
+        Throw "Could not download NuGet.exe."
+    }
+}
+
+# Save nuget.exe path to environment to be available to child processed
+$ENV:NUGET_EXE = $NUGET_EXE
+
+# Restore tools from NuGet?
+if(-Not $SkipToolPackageRestore.IsPresent) {
+    Push-Location
+    Set-Location $TOOLS_DIR
+
+    # Check for changes in packages.config and remove installed tools if true.
+    [string] $md5Hash = MD5HashFile($PACKAGES_CONFIG)
+    if((!(Test-Path $PACKAGES_CONFIG_MD5)) -Or
+      ($md5Hash -ne (Get-Content $PACKAGES_CONFIG_MD5 ))) {
+        Write-Verbose -Message "Missing or changed package.config hash..."
+        Remove-Item * -Recurse -Exclude packages.config,nuget.exe
+    }
+
+    Write-Verbose -Message "Restoring tools from NuGet..."
+    $NuGetOutput = Invoke-Expression "&`"$NUGET_EXE`" install -ExcludeVersion -OutputDirectory `"$TOOLS_DIR`""
+
+    if ($LASTEXITCODE -ne 0) {
+        Throw "An error occured while restoring NuGet tools."
+    }
+    else
+    {
+        $md5Hash | Out-File $PACKAGES_CONFIG_MD5 -Encoding "ASCII"
+    }
+    Write-Verbose -Message ($NuGetOutput | out-string)
+    
+    Pop-Location
+}
+
+# Restore addins from NuGet
+if (Test-Path $ADDINS_PACKAGES_CONFIG) {
+    Push-Location
+    Set-Location $ADDINS_DIR
+
+    Write-Verbose -Message "Restoring addins from NuGet..."
+    $NuGetOutput = Invoke-Expression "&`"$NUGET_EXE`" install -ExcludeVersion -OutputDirectory `"$ADDINS_DIR`""
+
+    if ($LASTEXITCODE -ne 0) {
+        Throw "An error occured while restoring NuGet addins."
+    }
+
+    Write-Verbose -Message ($NuGetOutput | out-string)
+
+    Pop-Location
+}
+
+# Restore modules from NuGet
+if (Test-Path $MODULES_PACKAGES_CONFIG) {
+    Push-Location
+    Set-Location $MODULES_DIR
+
+    Write-Verbose -Message "Restoring modules from NuGet..."
+    $NuGetOutput = Invoke-Expression "&`"$NUGET_EXE`" install -ExcludeVersion -OutputDirectory `"$MODULES_DIR`""
+
+    if ($LASTEXITCODE -ne 0) {
+        Throw "An error occured while restoring NuGet modules."
+    }
+
+    Write-Verbose -Message ($NuGetOutput | out-string)
+
+    Pop-Location
+}
+
+# Make sure that Cake has been installed.
+if (!(Test-Path $CAKE_EXE)) {
+    Throw "Could not find Cake.exe at $CAKE_EXE"
+}
+
+# Start Cake
+Write-Host "Running build script..."
+Invoke-Expression "& `"$CAKE_EXE`" `"$Script`" -target=`"$Target`" -configuration=`"$Configuration`" -verbosity=`"$Verbosity`" $UseMono $UseDryRun $UseExperimental $ScriptArgs"
+exit $LASTEXITCODE

build.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+##########################################################################
+# This is the Cake bootstrapper script for Linux and OS X.
+# This file was downloaded from https://github.com/cake-build/resources
+# Feel free to change this file to fit your needs.
+##########################################################################
+
+# Define directories.
+SCRIPT_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+TOOLS_DIR=$SCRIPT_DIR/tools
+CAKE_VERSION=0.19.1
+CAKE_DLL=$TOOLS_DIR/Cake.CoreCLR.$CAKE_VERSION/Cake.dll
+
+# Make sure the tools folder exist.
+if [ ! -d "$TOOLS_DIR" ]; then
+  mkdir "$TOOLS_DIR"
+fi
+
+###########################################################################
+# INSTALL CAKE
+###########################################################################
+
+if [ ! -f "$CAKE_DLL" ]; then
+    curl -Lsfo Cake.CoreCLR.zip "https://www.nuget.org/api/v2/package/Cake.CoreCLR/$CAKE_VERSION" && unzip -q Cake.CoreCLR.zip -d "$TOOLS_DIR/Cake.CoreCLR.$CAKE_VERSION" && rm -f Cake.CoreCLR.zip
+    if [ $? -ne 0 ]; then
+        echo "An error occured while installing Cake."
+        exit 1
+    fi
+fi
+
+# Make sure that Cake has been installed.
+if [ ! -f "$CAKE_DLL" ]; then
+    echo "Could not find Cake.exe at '$CAKE_DLL'."
+    exit 1
+fi
+
+###########################################################################
+# RUN BUILD SCRIPT
+###########################################################################
+
+# Start Cake
+exec dotnet "$CAKE_DLL" "$@"

src/SharpCompress/Archives/ArchiveFactory.cs

@@ -6,6 +6,7 @@ using SharpCompress.Archives.SevenZip;
 using SharpCompress.Archives.Tar;
 using SharpCompress.Archives.Zip;
 using SharpCompress.Common;
+using SharpCompress.Compressors.LZMA;
 using SharpCompress.Readers;
 
 namespace SharpCompress.Archives
@@ -55,7 +56,7 @@ namespace SharpCompress.Archives
                 stream.Seek(0, SeekOrigin.Begin);
                 return TarArchive.Open(stream, readerOptions);
             }
-            throw new InvalidOperationException("Cannot determine compressed stream type. Supported Archive Formats: Zip, GZip, Tar, Rar, 7Zip");
+            throw new InvalidOperationException("Cannot determine compressed stream type. Supported Archive Formats: Zip, GZip, Tar, Rar, 7Zip, LZip");
         }
 
         public static IWritableArchive Create(ArchiveType type)

src/SharpCompress/Archives/GZip/GZipArchive.cs

@@ -14,6 +14,7 @@ namespace SharpCompress.Archives.GZip
     public class GZipArchive : AbstractWritableArchive<GZipArchiveEntry, GZipVolume>
     {
 #if !NO_FILE
+
         /// <summary>
         /// Constructor expects a filepath to an existing file.
         /// </summary>
@@ -36,6 +37,7 @@ namespace SharpCompress.Archives.GZip
             return new GZipArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 #endif
+
         /// <summary>
         /// Takes a seekable Stream as a source
         /// </summary>
@@ -54,11 +56,11 @@ namespace SharpCompress.Archives.GZip
 
 #if !NO_FILE
 
-/// <summary>
-/// Constructor with a FileInfo object to an existing file.
-/// </summary>
-/// <param name="fileInfo"></param>
-/// <param name="options"></param>
+        /// <summary>
+        /// Constructor with a FileInfo object to an existing file.
+        /// </summary>
+        /// <param name="fileInfo"></param>
+        /// <param name="options"></param>
         internal GZipArchive(FileInfo fileInfo, ReaderOptions options)
             : base(ArchiveType.GZip, fileInfo, options)
         {
@@ -104,15 +106,9 @@ namespace SharpCompress.Archives.GZip
         {
             // read the header on the first read
             byte[] header = new byte[10];
-            int n = stream.Read(header, 0, header.Length);
 
             // workitem 8501: handle edge case (decompress empty stream)
-            if (n == 0)
-            {
-                return false;
-            }
-
-            if (n != 10)
+            if (!stream.ReadFully(header))
             {
                 return false;
             }
@@ -158,7 +154,7 @@ namespace SharpCompress.Archives.GZip
             {
                 throw new InvalidOperationException("Only one entry is allowed in a GZip Archive");
             }
-            using (var writer = new GZipWriter(stream))
+            using (var writer = new GZipWriter(stream, new GZipWriterOptions(options)))
             {
                 foreach (var entry in oldEntries.Concat(newEntries)
                                                 .Where(x => !x.IsDirectory))
@@ -179,7 +175,7 @@ namespace SharpCompress.Archives.GZip
         protected override IEnumerable<GZipArchiveEntry> LoadEntries(IEnumerable<GZipVolume> volumes)
         {
             Stream stream = volumes.Single().Stream;
-            yield return new GZipArchiveEntry(this, new GZipFilePart(stream));
+            yield return new GZipArchiveEntry(this, new GZipFilePart(stream, ReaderOptions.ArchiveEncoding));
         }
 
         protected override IReader CreateReaderForSolidExtraction()

src/SharpCompress/Archives/SevenZip/SevenZipArchive.cs

@@ -106,7 +106,7 @@ namespace SharpCompress.Archives.SevenZip
             for (int i = 0; i < database.Files.Count; i++)
             {
                 var file = database.Files[i];
-                yield return new SevenZipArchiveEntry(this, new SevenZipFilePart(stream, database, i, file));
+                yield return new SevenZipArchiveEntry(this, new SevenZipFilePart(stream, database, i, file, ReaderOptions.ArchiveEncoding));
             }
         }
 

src/SharpCompress/Archives/Tar/TarArchive.cs

@@ -16,7 +16,7 @@ namespace SharpCompress.Archives.Tar
     public class TarArchive : AbstractWritableArchive<TarArchiveEntry, TarVolume>
     {
 #if !NO_FILE
-        
+
         /// <summary>
         /// Constructor expects a filepath to an existing file.
         /// </summary>
@@ -39,7 +39,7 @@ namespace SharpCompress.Archives.Tar
             return new TarArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 #endif
-        
+
         /// <summary>
         /// Takes a seekable Stream as a source
         /// </summary>
@@ -52,6 +52,7 @@ namespace SharpCompress.Archives.Tar
         }
 
 #if !NO_FILE
+
         public static bool IsTarFile(string filePath)
         {
             return IsTarFile(new FileInfo(filePath));
@@ -74,7 +75,7 @@ namespace SharpCompress.Archives.Tar
         {
             try
             {
-                TarHeader tar = new TarHeader();
+                TarHeader tar = new TarHeader(new ArchiveEncoding());
                 tar.Read(new BinaryReader(stream));
                 return tar.Name.Length > 0 && Enum.IsDefined(typeof(EntryType), tar.EntryType);
             }
@@ -98,7 +99,6 @@ namespace SharpCompress.Archives.Tar
 
         protected override IEnumerable<TarVolume> LoadVolumes(FileInfo file)
         {
-            
             return new TarVolume(file.OpenRead(), ReaderOptions).AsEnumerable();
         }
 #endif
@@ -127,7 +127,7 @@ namespace SharpCompress.Archives.Tar
         {
             Stream stream = volumes.Single().Stream;
             TarHeader previousHeader = null;
-            foreach (TarHeader header in TarHeaderFactory.ReadHeader(StreamingMode.Seekable, stream))
+            foreach (TarHeader header in TarHeaderFactory.ReadHeader(StreamingMode.Seekable, stream, ReaderOptions.ArchiveEncoding))
             {
                 if (header != null)
                 {
@@ -152,7 +152,7 @@ namespace SharpCompress.Archives.Tar
                                     memoryStream.Position = 0;
                                     var bytes = memoryStream.ToArray();
 
-                                    header.Name = ArchiveEncoding.Default.GetString(bytes, 0, bytes.Length).TrimNulls();
+                                    header.Name = ReaderOptions.ArchiveEncoding.Decode(bytes).TrimNulls();
                                 }
                             }
 

src/SharpCompress/Archives/Zip/ZipArchive.cs

@@ -24,6 +24,7 @@ namespace SharpCompress.Archives.Zip
         public CompressionLevel DeflateCompressionLevel { get; set; }
 
 #if !NO_FILE
+
         /// <summary>
         /// Constructor expects a filepath to an existing file.
         /// </summary>
@@ -46,6 +47,7 @@ namespace SharpCompress.Archives.Zip
             return new ZipArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 #endif
+
         /// <summary>
         /// Takes a seekable Stream as a source
         /// </summary>
@@ -58,6 +60,7 @@ namespace SharpCompress.Archives.Zip
         }
 
 #if !NO_FILE
+
         public static bool IsZipFile(string filePath, string password = null)
         {
             return IsZipFile(new FileInfo(filePath), password);
@@ -78,7 +81,7 @@ namespace SharpCompress.Archives.Zip
 
         public static bool IsZipFile(Stream stream, string password = null)
         {
-            StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password);
+            StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding());
             try
             {
                 ZipHeader header =
@@ -109,7 +112,7 @@ namespace SharpCompress.Archives.Zip
         internal ZipArchive(FileInfo fileInfo, ReaderOptions readerOptions)
             : base(ArchiveType.Zip, fileInfo, readerOptions)
         {
-            headerFactory = new SeekableZipHeaderFactory(readerOptions.Password);
+            headerFactory = new SeekableZipHeaderFactory(readerOptions.Password, readerOptions.ArchiveEncoding);
         }
 
         protected override IEnumerable<ZipVolume> LoadVolumes(FileInfo file)
@@ -131,7 +134,7 @@ namespace SharpCompress.Archives.Zip
         internal ZipArchive(Stream stream, ReaderOptions readerOptions)
             : base(ArchiveType.Zip, stream, readerOptions)
         {
-            headerFactory = new SeekableZipHeaderFactory(readerOptions.Password);
+            headerFactory = new SeekableZipHeaderFactory(readerOptions.Password, readerOptions.ArchiveEncoding);
         }
 
         protected override IEnumerable<ZipVolume> LoadVolumes(IEnumerable<Stream> streams)
@@ -150,19 +153,19 @@ namespace SharpCompress.Archives.Zip
                     switch (h.ZipHeaderType)
                     {
                         case ZipHeaderType.DirectoryEntry:
-                        {
-                            yield return new ZipArchiveEntry(this,
-                                                             new SeekableZipFilePart(headerFactory,
-                                                                                     h as DirectoryEntryHeader,
-                                                                                     stream));
-                        }
+                            {
+                                yield return new ZipArchiveEntry(this,
+                                                                 new SeekableZipFilePart(headerFactory,
+                                                                                         h as DirectoryEntryHeader,
+                                                                                         stream));
+                            }
                             break;
                         case ZipHeaderType.DirectoryEnd:
-                        {
-                            byte[] bytes = (h as DirectoryEndHeader).Comment;
-                            volume.Comment = ArchiveEncoding.Default.GetString(bytes, 0, bytes.Length);
-                            yield break;
-                        }
+                            {
+                                byte[] bytes = (h as DirectoryEndHeader).Comment;
+                                volume.Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
+                                yield break;
+                            }
                     }
                 }
             }
@@ -205,7 +208,7 @@ namespace SharpCompress.Archives.Zip
         {
             var stream = Volumes.Single().Stream;
             stream.Position = 0;
-            return ZipReader.Open(stream);
+            return ZipReader.Open(stream, ReaderOptions);
         }
     }
 }

src/SharpCompress/Common/ArchiveEncoding.cs

@@ -1,23 +1,60 @@
-using System.Text;
+using System;
+using System.Text;
 
 namespace SharpCompress.Common
 {
-    public static class ArchiveEncoding
+    public class ArchiveEncoding
     {
         /// <summary>
         /// Default encoding to use when archive format doesn't specify one.
         /// </summary>
-        public static Encoding Default { get; set; }
+        public Encoding Default { get; set; }
 
         /// <summary>
-        /// Encoding used by encryption schemes which don't comply with RFC 2898.
+        /// ArchiveEncoding used by encryption schemes which don't comply with RFC 2898.
         /// </summary>
-        public static Encoding Password { get; set; }
+        public Encoding Password { get; set; }
 
-        static ArchiveEncoding()
+        /// <summary>
+        /// Set this encoding when you want to force it for all encoding operations.
+        /// </summary>
+        public Encoding Forced { get; set; }
+
+        /// <summary>
+        /// Set this when you want to use a custom method for all decoding operations.
+        /// </summary>
+        /// <returns>string Func(bytes, index, length)</returns>
+        public Func<byte[], int, int, string> CustomDecoder { get; set; }
+
+        public ArchiveEncoding()
         {
             Default = Encoding.UTF8;
             Password = Encoding.UTF8;
         }
+
+        public string Decode(byte[] bytes)
+        {
+            return Decode(bytes, 0, bytes.Length);
+        }
+
+        public string Decode(byte[] bytes, int start, int length)
+        {
+            return GetDecoder().Invoke(bytes, start, length);
+        }
+
+        public byte[] Encode(string str)
+        {
+            return GetEncoding().GetBytes(str);
+        }
+
+        public Encoding GetEncoding()
+        {
+            return Forced ?? Default ?? Encoding.UTF8;
+        }
+
+        public Func<byte[], int, int, string> GetDecoder()
+        {
+            return CustomDecoder ?? ((bytes, index, count) => (Default ?? Encoding.UTF8).GetString(bytes, index, count));
+        }
     }
 }

src/SharpCompress/Common/ArchiveExtractionEventArgs.cs

@@ -9,6 +9,6 @@ namespace SharpCompress.Common
             Item = entry;
         }
 
-        public T Item { get; private set; }
+        public T Item { get; }
     }
 }

src/SharpCompress/Common/CompressionType.cs

@@ -12,6 +12,7 @@
         BCJ,
         BCJ2,
         LZip,
+        Xz,
         Unknown
     }
 }

src/SharpCompress/Common/FilePart.cs

@@ -4,9 +4,17 @@ namespace SharpCompress.Common
 {
     public abstract class FilePart
     {
+        protected FilePart(ArchiveEncoding archiveEncoding)
+        {
+            ArchiveEncoding = archiveEncoding;
+        }
+
+        internal ArchiveEncoding ArchiveEncoding { get; }
+        
         internal abstract string FilePartName { get; }
 
         internal abstract Stream GetCompressedStream();
         internal abstract Stream GetRawStream();
+        internal bool Skipped { get; set; }
     }
 }

src/SharpCompress/Common/GZip/GZipEntry.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Text;
 
 namespace SharpCompress.Common.GZip
 {
@@ -39,9 +40,9 @@ namespace SharpCompress.Common.GZip
 
         internal override IEnumerable<FilePart> Parts => filePart.AsEnumerable<FilePart>();
 
-        internal static IEnumerable<GZipEntry> GetEntries(Stream stream)
+        internal static IEnumerable<GZipEntry> GetEntries(Stream stream, OptionsBase options)
         {
-            yield return new GZipEntry(new GZipFilePart(stream));
+            yield return new GZipEntry(new GZipFilePart(stream, options.ArchiveEncoding));
         }
     }
 }

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -5,35 +5,37 @@ using SharpCompress.Common.Tar.Headers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.Converters;
+using System.Text;
 
 namespace SharpCompress.Common.GZip
 {
     internal class GZipFilePart : FilePart
     {
-        private string name;
-        private readonly Stream stream;
+        private string _name;
+        private readonly Stream _stream;
 
-        internal GZipFilePart(Stream stream)
+        internal GZipFilePart(Stream stream, ArchiveEncoding archiveEncoding)
+        : base(archiveEncoding)
         {
             ReadAndValidateGzipHeader(stream);
             EntryStartPosition = stream.Position;
-            this.stream = stream;
+            this._stream = stream;
         }
 
         internal long EntryStartPosition { get; }
 
         internal DateTime? DateModified { get; private set; }
 
-        internal override string FilePartName => name;
+        internal override string FilePartName => _name;
 
         internal override Stream GetCompressedStream()
         {
-            return new DeflateStream(stream, CompressionMode.Decompress, CompressionLevel.Default, false);
+            return new DeflateStream(_stream, CompressionMode.Decompress, CompressionLevel.Default, false);
         }
 
         internal override Stream GetRawStream()
         {
-            return stream;
+            return _stream;
         }
 
         private void ReadAndValidateGzipHeader(Stream stream)
@@ -67,15 +69,16 @@ namespace SharpCompress.Common.GZip
 
                 Int16 extraLength = (Int16)(header[0] + header[1] * 256);
                 byte[] extra = new byte[extraLength];
-                n = stream.Read(extra, 0, extra.Length);
-                if (n != extraLength)
+                
+                if (!stream.ReadFully(extra))
                 {
                     throw new ZlibException("Unexpected end-of-file reading GZIP header.");
                 }
+                n = extraLength;
             }
             if ((header[3] & 0x08) == 0x08)
             {
-                name = ReadZeroTerminatedString(stream);
+                _name = ReadZeroTerminatedString(stream);
             }
             if ((header[3] & 0x10) == 0x010)
             {
@@ -87,7 +90,7 @@ namespace SharpCompress.Common.GZip
             }
         }
 
-        private static string ReadZeroTerminatedString(Stream stream)
+        private string ReadZeroTerminatedString(Stream stream)
         {
             byte[] buf1 = new byte[1];
             var list = new List<byte>();
@@ -110,8 +113,8 @@ namespace SharpCompress.Common.GZip
                 }
             }
             while (!done);
-            byte[] a = list.ToArray();
-            return ArchiveEncoding.Default.GetString(a, 0, a.Length);
+            byte[] buffer = list.ToArray();
+            return ArchiveEncoding.Decode(buffer);
         }
     }
 }

src/SharpCompress/Common/OptionsBase.cs

@@ -1,4 +1,5 @@
-namespace SharpCompress.Common
+
+namespace SharpCompress.Common
 {
     public class OptionsBase
     {
@@ -6,5 +7,7 @@
         /// SharpCompress will keep the supplied streams open.  Default is true.
         /// </summary>
         public bool LeaveStreamOpen { get; set; } = true;
+
+        public ArchiveEncoding ArchiveEncoding { get; set; } = new ArchiveEncoding();
     }
 }

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

@@ -1,6 +1,6 @@
+using SharpCompress.IO;
 using System;
 using System.IO;
-using SharpCompress.IO;
 
 namespace SharpCompress.Common.Rar.Headers
 {
@@ -52,50 +52,50 @@ namespace SharpCompress.Common.Rar.Headers
             switch (HeaderType)
             {
                 case HeaderType.FileHeader:
-                {
-                    if (FileFlags.HasFlag(FileFlags.UNICODE))
                     {
-                        int length = 0;
-                        while (length < fileNameBytes.Length
-                               && fileNameBytes[length] != 0)
+                        if (FileFlags.HasFlag(FileFlags.UNICODE))
                         {
-                            length++;
-                        }
-                        if (length != nameSize)
-                        {
-                            length++;
-                            FileName = FileNameDecoder.Decode(fileNameBytes, length);
+                            int length = 0;
+                            while (length < fileNameBytes.Length
+                                   && fileNameBytes[length] != 0)
+                            {
+                                length++;
+                            }
+                            if (length != nameSize)
+                            {
+                                length++;
+                                FileName = FileNameDecoder.Decode(fileNameBytes, length);
+                            }
+                            else
+                            {
+                                FileName = ArchiveEncoding.Decode(fileNameBytes);
+                            }
                         }
                         else
                         {
-                            FileName = DecodeDefault(fileNameBytes);
+                            FileName = ArchiveEncoding.Decode(fileNameBytes);
                         }
+                        FileName = ConvertPath(FileName, HostOS);
                     }
-                    else
-                    {
-                        FileName = DecodeDefault(fileNameBytes);
-                    }
-                    FileName = ConvertPath(FileName, HostOS);
-                }
                     break;
                 case HeaderType.NewSubHeader:
-                {
-                    int datasize = HeaderSize - NEWLHD_SIZE - nameSize;
-                    if (FileFlags.HasFlag(FileFlags.SALT))
                     {
-                        datasize -= SALT_SIZE;
-                    }
-                    if (datasize > 0)
-                    {
-                        SubData = reader.ReadBytes(datasize);
-                    }
+                        int datasize = HeaderSize - NEWLHD_SIZE - nameSize;
+                        if (FileFlags.HasFlag(FileFlags.SALT))
+                        {
+                            datasize -= SALT_SIZE;
+                        }
+                        if (datasize > 0)
+                        {
+                            SubData = reader.ReadBytes(datasize);
+                        }
 
-                    if (NewSubHeaderType.SUBHEAD_TYPE_RR.Equals(fileNameBytes))
-                    {
-                        RecoverySectors = SubData[8] + (SubData[9] << 8)
-                                          + (SubData[10] << 16) + (SubData[11] << 24);
+                        if (NewSubHeaderType.SUBHEAD_TYPE_RR.Equals(fileNameBytes))
+                        {
+                            RecoverySectors = SubData[8] + (SubData[9] << 8)
+                                              + (SubData[10] << 16) + (SubData[11] << 24);
+                        }
                     }
-                }
                     break;
             }
 
@@ -118,12 +118,6 @@ namespace SharpCompress.Common.Rar.Headers
             }
         }
 
-        //only the full .net framework will do other code pages than unicode/utf8
-        private string DecodeDefault(byte[] bytes)
-        {
-            return ArchiveEncoding.Default.GetString(bytes, 0, bytes.Length);
-        }
-
         private long UInt32To64(uint x, uint y)
         {
             long l = x;
@@ -165,31 +159,20 @@ namespace SharpCompress.Common.Rar.Headers
 #if NO_FILE
             return path.Replace('\\', '/');
 #else
-            switch (os)
+            if (Path.DirectorySeparatorChar == '/')
             {
-                case HostOS.MacOS:
-                case HostOS.Unix:
-                    {
-                        if (Path.DirectorySeparatorChar == '\\')
-                        {
-                            return path.Replace('/', '\\');
-                        }
-                    }
-                    break;
-                default:
-                    {
-                        if (Path.DirectorySeparatorChar == '/')
-                        {
-                            return path.Replace('\\', '/');
-                        }
-                    }
-                    break;
+                return path.Replace('\\', '/');
+            }
+            else if (Path.DirectorySeparatorChar == '\\')
+            {
+                return path.Replace('/', '\\');
             }
             return path;
 #endif
         }
 
         internal long DataStartPosition { get; set; }
+
         internal HostOS HostOS { get; private set; }
 
         internal uint FileCRC { get; private set; }
@@ -211,6 +194,7 @@ namespace SharpCompress.Common.Rar.Headers
         internal FileFlags FileFlags => (FileFlags)Flags;
 
         internal long CompressedSize { get; private set; }
+
         internal long UncompressedSize { get; private set; }
 
         internal string FileName { get; private set; }

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

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Rar.Headers
 {
@@ -17,14 +18,16 @@ namespace SharpCompress.Common.Rar.Headers
             HeaderSize = baseHeader.HeaderSize;
             AdditionalSize = baseHeader.AdditionalSize;
             ReadBytes = baseHeader.ReadBytes;
+            ArchiveEncoding = baseHeader.ArchiveEncoding;
         }
 
-        internal static RarHeader Create(RarCrcBinaryReader reader)
+        internal static RarHeader Create(RarCrcBinaryReader reader, ArchiveEncoding archiveEncoding)
         {
             try
             {
                 RarHeader header = new RarHeader();
 
+                header.ArchiveEncoding = archiveEncoding;
                 reader.Mark();
                 header.ReadStartFromReader(reader);
                 header.ReadBytes += reader.CurrentReadByteCount;
@@ -50,7 +53,8 @@ namespace SharpCompress.Common.Rar.Headers
             }
         }
 
-        protected virtual void ReadFromReader(MarkingBinaryReader reader) {
+        protected virtual void ReadFromReader(MarkingBinaryReader reader)
+        {
             throw new NotImplementedException();
         }
 
@@ -76,10 +80,11 @@ namespace SharpCompress.Common.Rar.Headers
             return header;
         }
 
-        private void VerifyHeaderCrc(ushort crc) {
-            if (HeaderType != HeaderType.MarkHeader) 
+        private void VerifyHeaderCrc(ushort crc)
+        {
+            if (HeaderType != HeaderType.MarkHeader)
             {
-                if (crc != HeadCRC) 
+                if (crc != HeadCRC)
                 {
                     throw new InvalidFormatException("rar header crc mismatch");
                 }
@@ -106,6 +111,8 @@ namespace SharpCompress.Common.Rar.Headers
 
         protected short HeaderSize { get; private set; }
 
+        internal ArchiveEncoding ArchiveEncoding { get; private set; }
+
         /// <summary>
         /// This additional size of the header could be file data
         /// </summary>

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

@@ -117,7 +117,7 @@ namespace SharpCompress.Common.Rar.Headers
         {
 #if !NO_CRYPTO
             var reader = new RarCryptoBinaryReader(stream, Options.Password);
-            
+
             if (IsEncrypted)
             {
                 if (Options.Password == null)
@@ -133,7 +133,7 @@ namespace SharpCompress.Common.Rar.Headers
 
 #endif
 
-            RarHeader header = RarHeader.Create(reader);
+            RarHeader header = RarHeader.Create(reader, Options.ArchiveEncoding);
             if (header == null)
             {
                 return null;
@@ -141,110 +141,110 @@ namespace SharpCompress.Common.Rar.Headers
             switch (header.HeaderType)
             {
                 case HeaderType.ArchiveHeader:
-                {
-                    var ah = header.PromoteHeader<ArchiveHeader>(reader);
-                    IsEncrypted = ah.HasPassword;
-                    return ah;
-                }
+                    {
+                        var ah = header.PromoteHeader<ArchiveHeader>(reader);
+                        IsEncrypted = ah.HasPassword;
+                        return ah;
+                    }
                 case HeaderType.MarkHeader:
-                {
-                    return header.PromoteHeader<MarkHeader>(reader);
-                }
+                    {
+                        return header.PromoteHeader<MarkHeader>(reader);
+                    }
 
                 case HeaderType.ProtectHeader:
-                {
-                    ProtectHeader ph = header.PromoteHeader<ProtectHeader>(reader);
-
-                    // skip the recovery record data, we do not use it.
-                    switch (StreamingMode)
                     {
-                        case StreamingMode.Seekable:
-                        {
-                            reader.BaseStream.Position += ph.DataSize;
-                        }
-                            break;
-                        case StreamingMode.Streaming:
-                        {
-                            reader.BaseStream.Skip(ph.DataSize);
-                        }
-                            break;
-                        default:
-                        {
-                            throw new InvalidFormatException("Invalid StreamingMode");
-                        }
-                    }
+                        ProtectHeader ph = header.PromoteHeader<ProtectHeader>(reader);
 
-                    return ph;
-                }
+                        // skip the recovery record data, we do not use it.
+                        switch (StreamingMode)
+                        {
+                            case StreamingMode.Seekable:
+                                {
+                                    reader.BaseStream.Position += ph.DataSize;
+                                }
+                                break;
+                            case StreamingMode.Streaming:
+                                {
+                                    reader.BaseStream.Skip(ph.DataSize);
+                                }
+                                break;
+                            default:
+                                {
+                                    throw new InvalidFormatException("Invalid StreamingMode");
+                                }
+                        }
+
+                        return ph;
+                    }
 
                 case HeaderType.NewSubHeader:
-                {
-                    FileHeader fh = header.PromoteHeader<FileHeader>(reader);
-                    switch (StreamingMode)
                     {
-                        case StreamingMode.Seekable:
+                        FileHeader fh = header.PromoteHeader<FileHeader>(reader);
+                        switch (StreamingMode)
                         {
-                            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);
-                        }
-                            break;
-                        default:
-                        {
-                            throw new InvalidFormatException("Invalid 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);
+                                }
+                                break;
+                            default:
+                                {
+                                    throw new InvalidFormatException("Invalid StreamingMode");
+                                }
                         }
+                        return fh;
                     }
-                    return fh;
-                }
                 case HeaderType.FileHeader:
-                {
-                    FileHeader fh = header.PromoteHeader<FileHeader>(reader);
-                    switch (StreamingMode)
                     {
-                        case StreamingMode.Seekable:
+                        FileHeader fh = header.PromoteHeader<FileHeader>(reader);
+                        switch (StreamingMode)
                         {
-                            fh.DataStartPosition = reader.BaseStream.Position;
-                            reader.BaseStream.Position += fh.CompressedSize;
-                        }
-                            break;
-                        case StreamingMode.Streaming:
-                        {
-                            var ms = new ReadOnlySubStream(reader.BaseStream, fh.CompressedSize);
-                            if (fh.Salt == null)
-                            {
-                                fh.PackedStream = ms;
-                            }
-                            else
-                            {
+                            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.Salt == null)
+                                    {
+                                        fh.PackedStream = ms;
+                                    }
+                                    else
+                                    {
 #if !NO_CRYPTO
-                                fh.PackedStream = new RarCryptoWrapper(ms, Options.Password,  fh.Salt);
+                                        fh.PackedStream = new RarCryptoWrapper(ms, Options.Password, fh.Salt);
 #else
                                 throw new NotSupportedException("RarCrypto not supported");
 #endif
-                            }
-                        }
-                            break;
-                        default:
-                        {
-                            throw new InvalidFormatException("Invalid StreamingMode");
+                                    }
+                                }
+                                break;
+                            default:
+                                {
+                                    throw new InvalidFormatException("Invalid StreamingMode");
+                                }
                         }
+                        return fh;
                     }
-                    return fh;
-                }
                 case HeaderType.EndArchiveHeader:
-                {
-                    return header.PromoteHeader<EndArchiveHeader>(reader);
-                }
+                    {
+                        return header.PromoteHeader<EndArchiveHeader>(reader);
+                    }
                 default:
-                {
-                    throw new InvalidFormatException("Invalid Rar Header: " + header.HeaderType);
-                }
+                    {
+                        throw new InvalidFormatException("Invalid Rar Header: " + header.HeaderType);
+                    }
             }
         }
     }
-}
+}

src/SharpCompress/Common/Rar/RarFilePart.cs

@@ -9,14 +9,15 @@ namespace SharpCompress.Common.Rar
     internal abstract class RarFilePart : FilePart
     {
         internal RarFilePart(MarkHeader mh, FileHeader fh)
+            : base(fh.ArchiveEncoding)
         {
             MarkHeader = mh;
             FileHeader = fh;
         }
 
-        internal MarkHeader MarkHeader { get; private set; }
+        internal MarkHeader MarkHeader { get; }
 
-        internal FileHeader FileHeader { get; private set; }
+        internal FileHeader FileHeader { get; }
 
         internal override Stream GetRawStream()
         {

src/SharpCompress/Common/ReaderExtractionEventArgs.cs

@@ -11,7 +11,7 @@ namespace SharpCompress.Common
             ReaderProgress = readerProgress;
         }
 
-        public T Item { get; private set; }
-        public ReaderProgress ReaderProgress { get; private set; }
+        public T Item { get; }
+        public ReaderProgress ReaderProgress { get; }
     }
 }

src/SharpCompress/Common/SevenZip/SevenZipFilePart.cs

@@ -7,14 +7,15 @@ namespace SharpCompress.Common.SevenZip
 {
     internal class SevenZipFilePart : FilePart
     {
-        private CompressionType? type;
-        private readonly Stream stream;
-        private readonly ArchiveDatabase database;
+        private CompressionType? _type;
+        private readonly Stream _stream;
+        private readonly ArchiveDatabase _database;
 
-        internal SevenZipFilePart(Stream stream, ArchiveDatabase database, int index, CFileItem fileEntry)
+        internal SevenZipFilePart(Stream stream, ArchiveDatabase database, int index, CFileItem fileEntry, ArchiveEncoding archiveEncoding)
+           : base(archiveEncoding)
         {
-            this.stream = stream;
-            this.database = database;
+            this._stream = stream;
+            this._database = database;
             Index = index;
             Header = fileEntry;
             if (Header.HasStream)
@@ -41,14 +42,14 @@ namespace SharpCompress.Common.SevenZip
             {
                 return null;
             }
-            var folderStream = database.GetFolderStream(stream, Folder, null);
+            var folderStream = _database.GetFolderStream(_stream, Folder, null);
 
-            int firstFileIndex = database.FolderStartFileIndex[database.Folders.IndexOf(Folder)];
+            int firstFileIndex = _database.FolderStartFileIndex[_database.Folders.IndexOf(Folder)];
             int skipCount = Index - firstFileIndex;
             long skipSize = 0;
             for (int i = 0; i < skipCount; i++)
             {
-                skipSize += database.Files[firstFileIndex + i].Size;
+                skipSize += _database.Files[firstFileIndex + i].Size;
             }
             if (skipSize > 0)
             {
@@ -61,11 +62,11 @@ namespace SharpCompress.Common.SevenZip
         {
             get
             {
-                if (type == null)
+                if (_type == null)
                 {
-                    type = GetCompression();
+                    _type = GetCompression();
                 }
-                return type.Value;
+                return _type.Value;
             }
         }
 
@@ -84,7 +85,7 @@ namespace SharpCompress.Common.SevenZip
         {
             var coder = Folder.Coders.First();
             switch (coder.MethodId.Id)
-            {
+            {                
                 case k_LZMA:
                 case k_LZMA2:
                 {

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

@@ -9,6 +9,11 @@ namespace SharpCompress.Common.Tar.Headers
     {
         internal static readonly DateTime Epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
+        public TarHeader(ArchiveEncoding archiveEncoding)
+        {
+            ArchiveEncoding = archiveEncoding;
+        }
+
         internal string Name { get; set; }
 
         //internal int Mode { get; set; }
@@ -20,6 +25,7 @@ namespace SharpCompress.Common.Tar.Headers
         internal DateTime LastModifiedTime { get; set; }
         internal EntryType EntryType { get; set; }
         internal Stream PackedStream { get; set; }
+        internal ArchiveEncoding ArchiveEncoding { get; }
 
         internal const int BlockSize = 512;
 
@@ -31,7 +37,7 @@ namespace SharpCompress.Common.Tar.Headers
             WriteOctalBytes(0, buffer, 108, 8); // owner ID
             WriteOctalBytes(0, buffer, 116, 8); // group ID
 
-            //Encoding.UTF8.GetBytes("magic").CopyTo(buffer, 257);
+            //ArchiveEncoding.UTF8.GetBytes("magic").CopyTo(buffer, 257);
             if (Name.Length > 100)
             {
                 // Set mock filename and filetype to indicate the next block is the actual name of the file
@@ -72,7 +78,7 @@ namespace SharpCompress.Common.Tar.Headers
 
         private void WriteLongFilenameHeader(Stream output)
         {
-            byte[] nameBytes = ArchiveEncoding.Default.GetBytes(Name);
+            byte[] nameBytes = ArchiveEncoding.Encode(Name);
             output.Write(nameBytes, 0, nameBytes.Length);
 
             // pad to multiple of BlockSize bytes, and make sure a terminating null is added
@@ -99,7 +105,7 @@ namespace SharpCompress.Common.Tar.Headers
             }
             else
             {
-                Name = ArchiveEncoding.Default.GetString(buffer, 0, 100).TrimNulls();
+                Name = ArchiveEncoding.Decode(buffer, 0, 100).TrimNulls();
             }
 
             EntryType = ReadEntryType(buffer);
@@ -111,12 +117,12 @@ namespace SharpCompress.Common.Tar.Headers
             long unixTimeStamp = ReadASCIIInt64Base8(buffer, 136, 11);
             LastModifiedTime = Epoch.AddSeconds(unixTimeStamp).ToLocalTime();
 
-            Magic = ArchiveEncoding.Default.GetString(buffer, 257, 6).TrimNulls();
+            Magic = ArchiveEncoding.Decode(buffer, 257, 6).TrimNulls();
 
             if (!string.IsNullOrEmpty(Magic)
                 && "ustar".Equals(Magic))
             {
-                string namePrefix = ArchiveEncoding.Default.GetString(buffer, 345, 157);
+                string namePrefix = ArchiveEncoding.Decode(buffer, 345, 157);
                 namePrefix = namePrefix.TrimNulls();
                 if (!string.IsNullOrEmpty(namePrefix))
                 {
@@ -143,7 +149,7 @@ namespace SharpCompress.Common.Tar.Headers
             {
                 reader.ReadBytes(remainingBytesToRead);
             }
-            return ArchiveEncoding.Default.GetString(nameBytes, 0, nameBytes.Length).TrimNulls();
+            return ArchiveEncoding.Decode(nameBytes, 0, nameBytes.Length).TrimNulls();
         }
 
         private static EntryType ReadEntryType(byte[] buffer)

src/SharpCompress/Common/Tar/TarEntry.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Tar
 {
@@ -43,9 +44,9 @@ namespace SharpCompress.Common.Tar
         internal override IEnumerable<FilePart> Parts => filePart.AsEnumerable<FilePart>();
 
         internal static IEnumerable<TarEntry> GetEntries(StreamingMode mode, Stream stream,
-                                                         CompressionType compressionType)
+                                                         CompressionType compressionType, ArchiveEncoding archiveEncoding)
         {
-            foreach (TarHeader h in TarHeaderFactory.ReadHeader(mode, stream))
+            foreach (TarHeader h in TarHeaderFactory.ReadHeader(mode, stream, archiveEncoding))
             {
                 if (h != null)
                 {

src/SharpCompress/Common/Tar/TarFilePart.cs

@@ -6,11 +6,12 @@ namespace SharpCompress.Common.Tar
 {
     internal class TarFilePart : FilePart
     {
-        private readonly Stream seekableStream;
+        private readonly Stream _seekableStream;
 
         internal TarFilePart(TarHeader header, Stream seekableStream)
+            : base(header.ArchiveEncoding)
         {
-            this.seekableStream = seekableStream;
+            this._seekableStream = seekableStream;
             Header = header;
         }
 
@@ -20,10 +21,10 @@ namespace SharpCompress.Common.Tar
 
         internal override Stream GetCompressedStream()
         {
-            if (seekableStream != null)
+            if (_seekableStream != null)
             {
-                seekableStream.Position = Header.DataStartPosition.Value;
-                return new ReadOnlySubStream(seekableStream, Header.Size);
+                _seekableStream.Position = Header.DataStartPosition.Value;
+                return new ReadOnlySubStream(_seekableStream, Header.Size);
             }
             return Header.PackedStream;
         }

src/SharpCompress/Common/Tar/TarHeaderFactory.cs

@@ -2,12 +2,13 @@
 using System.IO;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Tar
 {
     internal static class TarHeaderFactory
     {
-        internal static IEnumerable<TarHeader> ReadHeader(StreamingMode mode, Stream stream)
+        internal static IEnumerable<TarHeader> ReadHeader(StreamingMode mode, Stream stream, ArchiveEncoding archiveEncoding)
         {
             while (true)
             {
@@ -15,7 +16,8 @@ namespace SharpCompress.Common.Tar
                 try
                 {
                     BinaryReader reader = new BinaryReader(stream);
-                    header = new TarHeader();
+                    header = new TarHeader(archiveEncoding);
+
                     if (!header.Read(reader))
                     {
                         yield break;
@@ -23,22 +25,22 @@ namespace SharpCompress.Common.Tar
                     switch (mode)
                     {
                         case StreamingMode.Seekable:
-                        {
-                            header.DataStartPosition = reader.BaseStream.Position;
+                            {
+                                header.DataStartPosition = reader.BaseStream.Position;
 
-                            //skip to nearest 512
-                            reader.BaseStream.Position += PadTo512(header.Size);
-                        }
+                                //skip to nearest 512
+                                reader.BaseStream.Position += PadTo512(header.Size);
+                            }
                             break;
                         case StreamingMode.Streaming:
-                        {
-                            header.PackedStream = new TarReadOnlySubStream(stream, header.Size);
-                        }
+                            {
+                                header.PackedStream = new TarReadOnlySubStream(stream, header.Size);
+                            }
                             break;
                         default:
-                        {
-                            throw new InvalidFormatException("Invalid StreamingMode");
-                        }
+                            {
+                                throw new InvalidFormatException("Invalid StreamingMode");
+                            }
                     }
                 }
                 catch

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

@@ -21,18 +21,6 @@ namespace SharpCompress.Common.Zip.Headers
             Comment = reader.ReadBytes(CommentLength);
         }
 
-        internal override void Write(BinaryWriter writer)
-        {
-            writer.Write(VolumeNumber);
-            writer.Write(FirstVolumeWithDirectory);
-            writer.Write(TotalNumberOfEntriesInDisk);
-            writer.Write(TotalNumberOfEntries);
-            writer.Write(DirectorySize);
-            writer.Write(DirectoryStartOffsetRelativeToDisk);
-            writer.Write(CommentLength);
-            writer.Write(Comment);
-        }
-
         public ushort VolumeNumber { get; private set; }
 
         public ushort FirstVolumeWithDirectory { get; private set; }

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

@@ -6,8 +6,8 @@ namespace SharpCompress.Common.Zip.Headers
 {
     internal class DirectoryEntryHeader : ZipFileEntry
     {
-        public DirectoryEntryHeader()
-            : base(ZipHeaderType.DirectoryEntry)
+        public DirectoryEntryHeader(ArchiveEncoding archiveEncoding)
+            : base(ZipHeaderType.DirectoryEntry, archiveEncoding)
         {
         }
 
@@ -31,10 +31,10 @@ namespace SharpCompress.Common.Zip.Headers
             RelativeOffsetOfEntryHeader = reader.ReadUInt32();
 
             byte[] name = reader.ReadBytes(nameLength);
-            Name = DecodeString(name);
+            Name = ArchiveEncoding.Decode(name);
             byte[] extra = reader.ReadBytes(extraLength);
             byte[] comment = reader.ReadBytes(commentLength);
-            Comment = DecodeString(comment);
+            Comment = ArchiveEncoding.Decode(comment);
             LoadExtra(extra);
 
             var unicodePathExtra = Extra.FirstOrDefault(u => u.Type == ExtraDataType.UnicodePathExtraField);
@@ -61,56 +61,6 @@ namespace SharpCompress.Common.Zip.Headers
             }
         }
 
-        internal override void Write(BinaryWriter writer)
-        {
-            var zip64 = CompressedSize >= uint.MaxValue || UncompressedSize >= uint.MaxValue || RelativeOffsetOfEntryHeader >= uint.MaxValue;
-            if (zip64)
-                Version = (ushort)(Version > 45 ? Version : 45);
-
-            writer.Write(Version);
-            writer.Write(VersionNeededToExtract);
-            writer.Write((ushort)Flags);
-            writer.Write((ushort)CompressionMethod);
-            writer.Write(LastModifiedTime);
-            writer.Write(LastModifiedDate);
-            writer.Write(Crc);
-            writer.Write(zip64 ? uint.MaxValue : CompressedSize);
-            writer.Write(zip64 ? uint.MaxValue : UncompressedSize);
-
-            byte[] nameBytes = EncodeString(Name);
-            writer.Write((ushort)nameBytes.Length);
-
-            if (zip64)
-            {
-                writer.Write((ushort)(2 + 2 + 8 + 8 + 8 + 4));
-            }
-            else
-            {
-                //writer.Write((ushort)Extra.Length);
-                writer.Write((ushort)0);
-            }
-            writer.Write((ushort)Comment.Length);
-
-            writer.Write(DiskNumberStart);
-            writer.Write(InternalFileAttributes);
-            writer.Write(ExternalFileAttributes);
-            writer.Write(zip64 ? uint.MaxValue : RelativeOffsetOfEntryHeader);
-
-            writer.Write(nameBytes);
-
-            if (zip64)
-            {
-                writer.Write((ushort)0x0001);
-                writer.Write((ushort)((8 + 8 + 8 + 4)));
-
-                writer.Write((ulong)UncompressedSize);
-                writer.Write((ulong)CompressedSize);
-                writer.Write((ulong)RelativeOffsetOfEntryHeader);
-                writer.Write((uint)0); // VolumeNumber = 0
-            }
-            writer.Write(Comment);
-        }
-
         internal ushort Version { get; private set; }
 
         public ushort VersionNeededToExtract { get; set; }

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

@@ -5,6 +5,7 @@ namespace SharpCompress.Common.Zip.Headers
     [Flags]
     internal enum HeaderFlags : ushort
     {
+        None = 0,
         Encrypted = 1, // http://www.pkware.com/documents/casestudies/APPNOTE.TXT
         Bit1 = 2,
         Bit2 = 4,

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

@@ -13,10 +13,5 @@ namespace SharpCompress.Common.Zip.Headers
         internal override void Read(BinaryReader reader)
         {
         }
-
-        internal override void Write(BinaryWriter writer)
-        {
-            throw new NotImplementedException();
-        }
     }
 }

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

@@ -1,12 +1,13 @@
 using System.IO;
 using System.Linq;
+using System.Text;
 
 namespace SharpCompress.Common.Zip.Headers
 {
     internal class LocalEntryHeader : ZipFileEntry
     {
-        public LocalEntryHeader()
-            : base(ZipHeaderType.LocalEntry)
+        public LocalEntryHeader(ArchiveEncoding archiveEncoding)
+            : base(ZipHeaderType.LocalEntry, archiveEncoding)
         {
         }
 
@@ -24,7 +25,7 @@ namespace SharpCompress.Common.Zip.Headers
             ushort extraLength = reader.ReadUInt16();
             byte[] name = reader.ReadBytes(nameLength);
             byte[] extra = reader.ReadBytes(extraLength);
-            Name = DecodeString(name);
+            Name = ArchiveEncoding.Decode(name);
             LoadExtra(extra);
 
             var unicodePathExtra = Extra.FirstOrDefault(u => u.Type == ExtraDataType.UnicodePathExtraField);
@@ -47,56 +48,6 @@ namespace SharpCompress.Common.Zip.Headers
             }
         }
 
-        internal override void Write(BinaryWriter writer)
-        {
-            if (IsZip64)
-                Version = (ushort)(Version > 45 ? Version : 45);
-
-            writer.Write(Version);
-            
-            writer.Write((ushort)Flags);
-            writer.Write((ushort)CompressionMethod);
-            writer.Write(LastModifiedTime);
-            writer.Write(LastModifiedDate);
-            writer.Write(Crc);
-
-            if (IsZip64)
-            {
-                writer.Write(uint.MaxValue);
-                writer.Write(uint.MaxValue);
-            }
-            else
-            {
-                writer.Write(CompressedSize);
-                writer.Write(UncompressedSize);
-            }
-
-            byte[] nameBytes = EncodeString(Name);
-
-            writer.Write((ushort)nameBytes.Length);
-            if (IsZip64)
-            {
-                writer.Write((ushort)(2 + 2 + (2 * 8)));
-            }
-            else
-            {
-                writer.Write((ushort)0);
-            }
-
-            //if (Extra != null)
-            //{
-            //    writer.Write(Extra);
-            //}
-            writer.Write(nameBytes);
-            if (IsZip64)
-            {
-                writer.Write((ushort)0x0001);
-                writer.Write((ushort)(2 * 8));
-                writer.Write((ulong)CompressedSize);
-                writer.Write((ulong)UncompressedSize);
-            }
-        }
-
         internal ushort Version { get; private set; }
     }
 }

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

@@ -14,10 +14,5 @@ namespace SharpCompress.Common.Zip.Headers
         {
             throw new NotImplementedException();
         }
-
-        internal override void Write(BinaryWriter writer)
-        {
-            throw new NotImplementedException();
-        }
     }
 }

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

@@ -26,11 +26,6 @@ namespace SharpCompress.Common.Zip.Headers
 
         const int SizeOfFixedHeaderDataExceptSignatureAndSizeFields = 44;
 
-        internal override void Write(BinaryWriter writer)
-        {
-            throw new NotImplementedException();
-        }
-
         public long SizeOfDirectoryEndRecord { get; private set; }
 
         public ushort VersionMadeBy { get; private set; }

src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndLocatorHeader.cs

@@ -16,11 +16,6 @@ namespace SharpCompress.Common.Zip.Headers
             TotalNumberOfVolumes = reader.ReadUInt32();
         }
 
-        internal override void Write(BinaryWriter writer)
-        {
-            throw new System.NotImplementedException();
-        }
-
         public uint FirstVolumeWithDirectory { get; private set; }
 
         public long RelativeOffsetOfTheEndOfDirectoryRecord { get; private set; }

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

@@ -8,10 +8,11 @@ namespace SharpCompress.Common.Zip.Headers
 {
     internal abstract class ZipFileEntry : ZipHeader
     {
-        protected ZipFileEntry(ZipHeaderType type)
+        protected ZipFileEntry(ZipHeaderType type, ArchiveEncoding archiveEncoding)
             : base(type)
         {
             Extra = new List<ExtraData>();
+            ArchiveEncoding = archiveEncoding;
         }
 
         internal bool IsDirectory
@@ -29,28 +30,11 @@ namespace SharpCompress.Common.Zip.Headers
                        && Name.EndsWith("\\");
             }
         }
-
-        protected string DecodeString(byte[] str)
-        {
-            if (FlagUtility.HasFlag(Flags, HeaderFlags.UTF8))
-            {
-                return Encoding.UTF8.GetString(str, 0, str.Length);
-            }
-
-            return ArchiveEncoding.Default.GetString(str, 0, str.Length);
-        }
-
-        protected byte[] EncodeString(string str)
-        {
-            if (FlagUtility.HasFlag(Flags, HeaderFlags.UTF8))
-            {
-                return Encoding.UTF8.GetBytes(str);
-            }
-            return ArchiveEncoding.Default.GetBytes(str);
-        }
-
+        
         internal Stream PackedStream { get; set; }
 
+        internal ArchiveEncoding ArchiveEncoding { get; }
+
         internal string Name { get; set; }
 
         internal HeaderFlags Flags { get; set; }
@@ -64,7 +48,7 @@ namespace SharpCompress.Common.Zip.Headers
         internal long UncompressedSize { get; set; }
 
         internal List<ExtraData> Extra { get; set; }
-        
+
         public string Password { get; set; }
 
         internal PkwareTraditionalEncryptionData ComposeEncryptionData(Stream archiveStream)
@@ -75,10 +59,10 @@ namespace SharpCompress.Common.Zip.Headers
             }
 
             var buffer = new byte[12];
-            archiveStream.Read(buffer, 0, 12);
+            archiveStream.ReadFully(buffer);
 
             PkwareTraditionalEncryptionData encryptionData = PkwareTraditionalEncryptionData.ForRead(Password, this, buffer);
-            
+
             return encryptionData;
         }
 

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

@@ -10,12 +10,10 @@ namespace SharpCompress.Common.Zip.Headers
             HasData = true;
         }
 
-        internal ZipHeaderType ZipHeaderType { get; private set; }
+        internal ZipHeaderType ZipHeaderType { get; }
 
         internal abstract void Read(BinaryReader reader);
 
-        internal abstract void Write(BinaryWriter writer);
-
         internal bool HasData { get; set; }
     }
 }

src/SharpCompress/Common/Zip/PkwareTraditionalCryptoStream.cs

@@ -42,7 +42,7 @@ namespace SharpCompress.Common.Zip
 
             if (buffer == null)
             {
-                throw new ArgumentNullException("buffer");
+                throw new ArgumentNullException(nameof(buffer));
             }
 
             byte[] temp = new byte[count];

src/SharpCompress/Common/Zip/PkwareTraditionalEncryptionData.cs

@@ -9,9 +9,11 @@ namespace SharpCompress.Common.Zip
     {
         private static readonly CRC32 crc32 = new CRC32();
         private readonly UInt32[] _Keys = {0x12345678, 0x23456789, 0x34567890};
+        private readonly ArchiveEncoding _archiveEncoding;
 
-        private PkwareTraditionalEncryptionData(string password)
+        private PkwareTraditionalEncryptionData(string password, ArchiveEncoding archiveEncoding)
         {
+            _archiveEncoding = archiveEncoding;
             Initialize(password);
         }
 
@@ -27,7 +29,7 @@ namespace SharpCompress.Common.Zip
         public static PkwareTraditionalEncryptionData ForRead(string password, ZipFileEntry header,
                                                               byte[] encryptionHeader)
         {
-            var encryptor = new PkwareTraditionalEncryptionData(password);
+            var encryptor = new PkwareTraditionalEncryptionData(password, header.ArchiveEncoding);
             byte[] plainTextHeader = encryptor.Decrypt(encryptionHeader, encryptionHeader.Length);
             if (plainTextHeader[11] != (byte)((header.Crc >> 24) & 0xff))
             {
@@ -47,7 +49,7 @@ namespace SharpCompress.Common.Zip
         {
             if (length > cipherText.Length)
             {
-                throw new ArgumentOutOfRangeException("length",
+                throw new ArgumentOutOfRangeException(nameof(length),
                                                       "Bad length during Decryption: the length parameter must be smaller than or equal to the size of the destination array.");
             }
 
@@ -70,7 +72,7 @@ namespace SharpCompress.Common.Zip
 
             if (length > plainText.Length)
             {
-                throw new ArgumentOutOfRangeException("length",
+                throw new ArgumentOutOfRangeException(nameof(length),
                                                       "Bad length during Encryption: The length parameter must be smaller than or equal to the size of the destination array.");
             }
 
@@ -93,17 +95,12 @@ namespace SharpCompress.Common.Zip
             }
         }
 
-        internal static byte[] StringToByteArray(string value, Encoding encoding)
+        internal byte[] StringToByteArray(string value)
         {
-            byte[] a = encoding.GetBytes(value);
+            byte[] a = _archiveEncoding.Password.GetBytes(value);
             return a;
         }
 
-        internal static byte[] StringToByteArray(string value)
-        {
-            return StringToByteArray(value, ArchiveEncoding.Password);
-        }
-
         private void UpdateKeys(byte byteValue)
         {
             _Keys[0] = (UInt32)crc32.ComputeCrc32((int)_Keys[0], byteValue);

src/SharpCompress/Common/Zip/SeekableZipFilePart.cs

@@ -5,21 +5,21 @@ namespace SharpCompress.Common.Zip
 {
     internal class SeekableZipFilePart : ZipFilePart
     {
-        private bool isLocalHeaderLoaded;
-        private readonly SeekableZipHeaderFactory headerFactory;
+        private bool _isLocalHeaderLoaded;
+        private readonly SeekableZipHeaderFactory _headerFactory;
 
         internal SeekableZipFilePart(SeekableZipHeaderFactory headerFactory, DirectoryEntryHeader header, Stream stream)
             : base(header, stream)
         {
-            this.headerFactory = headerFactory;
+            this._headerFactory = headerFactory;
         }
 
         internal override Stream GetCompressedStream()
         {
-            if (!isLocalHeaderLoaded)
+            if (!_isLocalHeaderLoaded)
             {
                 LoadLocalHeader();
-                isLocalHeaderLoaded = true;
+                _isLocalHeaderLoaded = true;
             }
             return base.GetCompressedStream();
         }
@@ -29,7 +29,7 @@ namespace SharpCompress.Common.Zip
         private void LoadLocalHeader()
         {
             bool hasData = Header.HasData;
-            Header = headerFactory.GetLocalHeader(BaseStream, Header as DirectoryEntryHeader);
+            Header = _headerFactory.GetLocalHeader(BaseStream, Header as DirectoryEntryHeader);
             Header.HasData = hasData;
         }
 

src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs

@@ -3,16 +3,17 @@ using System.Collections.Generic;
 using System.IO;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Zip
 {
     internal class SeekableZipHeaderFactory : ZipHeaderFactory
     {
         private const int MAX_ITERATIONS_FOR_DIRECTORY_HEADER = 4096;
-        private bool zip64;
+        private bool _zip64;
 
-        internal SeekableZipHeaderFactory(string password)
-            : base(StreamingMode.Seekable, password)
+        internal SeekableZipHeaderFactory(string password, ArchiveEncoding archiveEncoding)
+            : base(StreamingMode.Seekable, password, archiveEncoding)
         {
         }
 
@@ -26,14 +27,14 @@ namespace SharpCompress.Common.Zip
 
             if (entry.IsZip64)
             {
-                zip64 = true;
+                _zip64 = true;
                 SeekBackToHeader(stream, reader, ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR);
                 var zip64Locator = new Zip64DirectoryEndLocatorHeader();
                 zip64Locator.Read(reader);
 
                 stream.Seek(zip64Locator.RelativeOffsetOfTheEndOfDirectoryRecord, SeekOrigin.Begin);
                 uint zip64Signature = reader.ReadUInt32();
-                if(zip64Signature != ZIP64_END_OF_CENTRAL_DIRECTORY)
+                if (zip64Signature != ZIP64_END_OF_CENTRAL_DIRECTORY)
                     throw new ArchiveException("Failed to locate the Zip64 Header");
 
                 var zip64Entry = new Zip64DirectoryEndHeader();
@@ -50,7 +51,7 @@ namespace SharpCompress.Common.Zip
             {
                 stream.Position = position;
                 uint signature = reader.ReadUInt32();
-                var directoryEntryHeader = ReadHeader(signature, reader, zip64) as DirectoryEntryHeader;
+                var directoryEntryHeader = ReadHeader(signature, reader, _zip64) as DirectoryEntryHeader;
                 position = stream.Position;
                 if (directoryEntryHeader == null)
                 {
@@ -91,7 +92,7 @@ namespace SharpCompress.Common.Zip
             stream.Seek(directoryEntryHeader.RelativeOffsetOfEntryHeader, SeekOrigin.Begin);
             BinaryReader reader = new BinaryReader(stream);
             uint signature = reader.ReadUInt32();
-            var localEntryHeader = ReadHeader(signature, reader, zip64) as LocalEntryHeader;
+            var localEntryHeader = ReadHeader(signature, reader, _zip64) as LocalEntryHeader;
             if (localEntryHeader == null)
             {
                 throw new InvalidOperationException();

src/SharpCompress/Common/Zip/StreamingZipFilePart.cs

@@ -25,7 +25,7 @@ namespace SharpCompress.Common.Zip
             {
                 return Stream.Null;
             }
-            decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()));
+            decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod);
             if (LeaveStreamOpen)
             {
                 return new NonDisposingStream(decompressionStream);
@@ -39,19 +39,20 @@ namespace SharpCompress.Common.Zip
             {
                 return new BinaryReader(rewindableStream);
             }
-            if (Header.HasData)
+            if (Header.HasData && !Skipped)
             {
                 if (decompressionStream == null)
                 {
                     decompressionStream = GetCompressedStream();
                 }
-                decompressionStream.SkipAll();
+                decompressionStream.Skip();
 
                 DeflateStream deflateStream = decompressionStream as DeflateStream;
                 if (deflateStream != null)
                 {
                     rewindableStream.Rewind(deflateStream.InputBuffer);
                 }
+                Skipped = true;
             }
             var reader = new BinaryReader(rewindableStream);
             decompressionStream = null;

src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs

@@ -2,13 +2,14 @@
 using System.IO;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Zip
 {
     internal class StreamingZipHeaderFactory : ZipHeaderFactory
     {
-        internal StreamingZipHeaderFactory(string password)
-            : base(StreamingMode.Streaming, password)
+        internal StreamingZipHeaderFactory(string password, ArchiveEncoding archiveEncoding)
+            : base(StreamingMode.Streaming, password, archiveEncoding)
         {
         }
 

src/SharpCompress/Common/Zip/WinzipAesCryptoStream.cs

@@ -78,7 +78,7 @@ namespace SharpCompress.Common.Zip
             {
                 //read out last 10 auth bytes
                 var ten = new byte[10];
-                stream.Read(ten, 0, 10);
+                stream.ReadFully(ten);
                 stream.Dispose();
             }
         }

src/SharpCompress/Common/Zip/ZipFilePart.cs

@@ -15,13 +15,14 @@ namespace SharpCompress.Common.Zip
     internal abstract class ZipFilePart : FilePart
     {
         internal ZipFilePart(ZipFileEntry header, Stream stream)
+        : base(header.ArchiveEncoding)
         {
             Header = header;
             header.Part = this;
             BaseStream = stream;
         }
 
-        internal Stream BaseStream { get; private set; }
+        internal Stream BaseStream { get; }
         internal ZipFileEntry Header { get; set; }
 
         internal override string FilePartName => Header.Name;
@@ -32,7 +33,7 @@ namespace SharpCompress.Common.Zip
             {
                 return Stream.Null;
             }
-            Stream decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()));
+            Stream decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod);
             if (LeaveStreamOpen)
             {
                 return new NonDisposingStream(decompressionStream);
@@ -53,9 +54,9 @@ namespace SharpCompress.Common.Zip
 
         protected bool LeaveStreamOpen => FlagUtility.HasFlag(Header.Flags, HeaderFlags.UsePostDataDescriptor) || Header.IsZip64;
 
-        protected Stream CreateDecompressionStream(Stream stream)
+        protected Stream CreateDecompressionStream(Stream stream, ZipCompressionMethod method)
         {
-            switch (Header.CompressionMethod)
+            switch (method)
             {
                 case ZipCompressionMethod.None:
                 {
@@ -88,7 +89,7 @@ namespace SharpCompress.Common.Zip
                 case ZipCompressionMethod.PPMd:
                 {
                     var props = new byte[2];
-                    stream.Read(props, 0, props.Length);
+                    stream.ReadFully(props);
                     return new PpmdStream(new PpmdProperties(props), stream, false);
                 }
                 case ZipCompressionMethod.WinzipAes:
@@ -102,9 +103,9 @@ namespace SharpCompress.Common.Zip
                     {
                         throw new InvalidFormatException("Winzip data length is not 7.");
                     }
-                    ushort method = DataConverter.LittleEndian.GetUInt16(data.DataBytes, 0);
+                    ushort compressedMethod = DataConverter.LittleEndian.GetUInt16(data.DataBytes, 0);
 
-                    if (method != 0x01 && method != 0x02)
+                    if (compressedMethod != 0x01 && compressedMethod != 0x02)
                     {
                         throw new InvalidFormatException("Unexpected vendor version number for WinZip AES metadata");
                     }
@@ -114,8 +115,7 @@ namespace SharpCompress.Common.Zip
                     {
                         throw new InvalidFormatException("Unexpected vendor ID for WinZip AES metadata");
                     }
-                    Header.CompressionMethod = (ZipCompressionMethod)DataConverter.LittleEndian.GetUInt16(data.DataBytes, 5);
-                    return CreateDecompressionStream(stream);
+                    return CreateDecompressionStream(stream, (ZipCompressionMethod)DataConverter.LittleEndian.GetUInt16(data.DataBytes, 5));
                 }
                 default:
                 {
@@ -176,7 +176,6 @@ namespace SharpCompress.Common.Zip
 
                 }
             }
-
             return plainStream;
         }
     }

src/SharpCompress/Common/Zip/ZipHeaderFactory.cs

@@ -5,6 +5,7 @@ using System.Linq;
 #endif
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
+using System.Text;
 
 namespace SharpCompress.Common.Zip
 {
@@ -23,11 +24,13 @@ namespace SharpCompress.Common.Zip
         protected LocalEntryHeader lastEntryHeader;
         private readonly string password;
         private readonly StreamingMode mode;
+        private readonly ArchiveEncoding archiveEncoding;
 
-        protected ZipHeaderFactory(StreamingMode mode, string password)
+        protected ZipHeaderFactory(StreamingMode mode, string password, ArchiveEncoding archiveEncoding)
         {
             this.mode = mode;
             this.password = password;
+            this.archiveEncoding = archiveEncoding;
         }
 
         protected ZipHeader ReadHeader(uint headerBytes, BinaryReader reader, bool zip64 = false)
@@ -36,7 +39,7 @@ namespace SharpCompress.Common.Zip
             {
                 case ENTRY_HEADER_BYTES:
                 {
-                    var entryHeader = new LocalEntryHeader();
+                    var entryHeader = new LocalEntryHeader(archiveEncoding);
                     entryHeader.Read(reader);
                     LoadHeader(entryHeader, reader.BaseStream);
 
@@ -45,48 +48,48 @@ namespace SharpCompress.Common.Zip
                 }
                 case DIRECTORY_START_HEADER_BYTES:
                 {
-                    var entry = new DirectoryEntryHeader();
+                    var entry = new DirectoryEntryHeader(archiveEncoding);
                     entry.Read(reader);
                     return entry;
                 }
                 case POST_DATA_DESCRIPTOR:
-                {
-                    if (FlagUtility.HasFlag(lastEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor))
                     {
-                        lastEntryHeader.Crc = reader.ReadUInt32();
-                        lastEntryHeader.CompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
-                        lastEntryHeader.UncompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
+                        if (FlagUtility.HasFlag(lastEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor))
+                        {
+                            lastEntryHeader.Crc = reader.ReadUInt32();
+                            lastEntryHeader.CompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
+                            lastEntryHeader.UncompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
+                        }
+                        else
+                        {
+                            reader.ReadBytes(zip64 ? 20 : 12);
+                        }
+                        return null;
                     }
-                    else
-                    {
-                        reader.ReadBytes(zip64 ? 20 : 12);
-                    }
-                    return null;
-                }
                 case DIGITAL_SIGNATURE:
                     return null;
                 case DIRECTORY_END_HEADER_BYTES:
-                {
-                    var entry = new DirectoryEndHeader();
-                    entry.Read(reader);
-                    return entry;
-                }
+                    {
+                        var entry = new DirectoryEndHeader();
+                        entry.Read(reader);
+                        return entry;
+                    }
                 case SPLIT_ARCHIVE_HEADER_BYTES:
-                {
-                    return new SplitHeader();
-                }
+                    {
+                        return new SplitHeader();
+                    }
                 case ZIP64_END_OF_CENTRAL_DIRECTORY:
-                {
-                    var entry = new Zip64DirectoryEndHeader();
-                    entry.Read(reader);
-                    return entry;
-                }
+                    {
+                        var entry = new Zip64DirectoryEndHeader();
+                        entry.Read(reader);
+                        return entry;
+                    }
                 case ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR:
-                {
-                    var entry = new Zip64DirectoryEndLocatorHeader();
-                    entry.Read(reader);
-                    return entry;
-                }
+                    {
+                        var entry = new Zip64DirectoryEndLocatorHeader();
+                        entry.Read(reader);
+                        return entry;
+                    }
                 default:
                     throw new NotSupportedException("Unknown header: " + headerBytes);
             }
@@ -165,22 +168,22 @@ namespace SharpCompress.Common.Zip
             switch (mode)
             {
                 case StreamingMode.Seekable:
-                {
-                    entryHeader.DataStartPosition = stream.Position;
-                    stream.Position += entryHeader.CompressedSize;
-                    break;
-                }
+                    {
+                        entryHeader.DataStartPosition = stream.Position;
+                        stream.Position += entryHeader.CompressedSize;
+                        break;
+                    }
 
                 case StreamingMode.Streaming:
-                {
-                    entryHeader.PackedStream = stream;
-                    break;
-                }
+                    {
+                        entryHeader.PackedStream = stream;
+                        break;
+                    }
 
                 default:
-                {
-                    throw new InvalidFormatException("Invalid StreamingMode");
-                }
+                    {
+                        throw new InvalidFormatException("Invalid StreamingMode");
+                    }
             }
 
             //}

src/SharpCompress/Compressors/ADC/ADCStream.cs

@@ -105,19 +105,19 @@ namespace SharpCompress.Compressors.ADC
             }
             if (buffer == null)
             {
-                throw new ArgumentNullException("buffer");
+                throw new ArgumentNullException(nameof(buffer));
             }
             if (count < 0)
             {
-                throw new ArgumentOutOfRangeException("count");
+                throw new ArgumentOutOfRangeException(nameof(count));
             }
             if (offset < buffer.GetLowerBound(0))
             {
-                throw new ArgumentOutOfRangeException("offset");
+                throw new ArgumentOutOfRangeException(nameof(offset));
             }
             if ((offset + count) > buffer.GetLength(0))
             {
-                throw new ArgumentOutOfRangeException("count");
+                throw new ArgumentOutOfRangeException(nameof(count));
             }
 
             int size = -1;

src/SharpCompress/Compressors/Deflate/CRC32.cs

@@ -99,7 +99,7 @@ namespace SharpCompress.Compressors.Deflate
         /// </summary>
         /// <param name="input">The stream over which to calculate the CRC32</param>
         /// <returns>the CRC32 calculation</returns>
-        public Int32 GetCrc32(Stream input)
+        public UInt32 GetCrc32(Stream input)
         {
             return GetCrc32AndCopy(input, null);
         }
@@ -111,7 +111,7 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="input">The stream over which to calculate the CRC32</param>
         /// <param name="output">The stream into which to deflate the input</param>
         /// <returns>the CRC32 calculation</returns>
-        public Int32 GetCrc32AndCopy(Stream input, Stream output)
+        public UInt32 GetCrc32AndCopy(Stream input, Stream output)
         {
             if (input == null)
             {
@@ -143,7 +143,7 @@ namespace SharpCompress.Compressors.Deflate
                     TotalBytesRead += count;
                 }
 
-                return (Int32)(~runningCrc32Result);
+                return ~runningCrc32Result;
             }
         }
 

src/SharpCompress/Compressors/Deflate/DeflateStream.cs

@@ -26,6 +26,7 @@
 
 using System;
 using System.IO;
+using System.Text;
 
 namespace SharpCompress.Compressors.Deflate
 {
@@ -36,9 +37,10 @@ namespace SharpCompress.Compressors.Deflate
 
         public DeflateStream(Stream stream, CompressionMode mode,
                              CompressionLevel level = CompressionLevel.Default,
-                             bool leaveOpen = false)
+                             bool leaveOpen = false,
+                             Encoding forceEncoding = null)
         {
-            _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.DEFLATE, leaveOpen);
+            _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.DEFLATE, leaveOpen, forceEncoding);
         }
 
         #region Zlib properties

src/SharpCompress/Compressors/Deflate/GZipStream.NetStandard13.cs

@@ -1,525 +0,0 @@
-#if NETSTANDARD1_3
-using System;
-using System.Collections.Generic;
-using System.IO;
-using SharpCompress.Common;
-using SharpCompress.Converters;
-
-namespace SharpCompress.Compressors.Deflate
-{
-    public class GZipStream : Stream
-    {
-        private enum Mode
-        {
-            Unknown,
-            Reader,
-            Writer
-        }
-
-        internal static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
-
-        public DateTime? LastModified { get; set; }
-        private byte[] _buf1 = new byte[1];
-        
-        private System.IO.Compression.DeflateStream BaseStream;
-        private bool disposed;
-        private Mode mode;
-
-
-        private string _GzipFileName;
-        private string _GzipComment;
-        private DateTime _GzipMtime;
-        private int _gzipHeaderByteCount;
-
-        public GZipStream(Stream stream, CompressionMode mode)
-            : this(stream, mode, CompressionLevel.Default, false)
-        {
-        }
-
-        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level)
-            : this(stream, mode, level, false)
-        {
-        }
-
-        public GZipStream(Stream stream, CompressionMode mode, bool leaveOpen)
-            : this(stream, mode, CompressionLevel.Default, leaveOpen)
-        {
-        }
-
-        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
-        {
-            if (mode == CompressionMode.Decompress)
-            {
-                BaseStream = new System.IO.Compression.DeflateStream(stream, System.IO.Compression.CompressionMode.Decompress, leaveOpen);
-            }
-            else
-            {
-                System.IO.Compression.CompressionLevel l;
-                switch (level)
-                {
-                    case CompressionLevel.BestSpeed:
-                    {
-                        l = System.IO.Compression.CompressionLevel.Fastest;
-                        break;
-                    }
-                    case CompressionLevel.None:
-                    {
-                        l = System.IO.Compression.CompressionLevel.NoCompression;
-                        break;
-                    }
-                    default:
-                    {
-                        l = System.IO.Compression.CompressionLevel.Optimal;
-                        break;
-                    }
-                }
-
-                BaseStream = new System.IO.Compression.DeflateStream(stream, l, leaveOpen);
-
-
-            }
-        }
-
-        #region Stream methods
-
-        /// <summary>
-        /// Indicates whether the stream can be read.
-        /// </summary>
-        /// <remarks>
-        /// The return value depends on whether the captive stream supports reading.
-        /// </remarks>
-        public override bool CanRead
-        {
-            get
-            {
-                if (disposed)
-                {
-                    throw new ObjectDisposedException("GZipStream");
-                }
-                return BaseStream.CanRead;
-            }
-        }
-
-        /// <summary>
-        /// Indicates whether the stream supports Seek operations.
-        /// </summary>
-        /// <remarks>
-        /// Always returns false.
-        /// </remarks>
-        public override bool CanSeek => false;
-
-        /// <summary>
-        /// Indicates whether the stream can be written.
-        /// </summary>
-        /// <remarks>
-        /// The return value depends on whether the captive stream supports writing.
-        /// </remarks>
-        public override bool CanWrite
-        {
-            get
-            {
-                if (disposed)
-                {
-                    throw new ObjectDisposedException("GZipStream");
-                }
-                return BaseStream.CanWrite;
-            }
-        }
-
-        /// <summary>
-        /// Reading this property always throws a <see cref="NotImplementedException"/>.
-        /// </summary>
-        public override long Length => throw new NotSupportedException();
-
-        /// <summary>
-        ///   The position of the stream pointer.
-        /// </summary>
-        ///
-        /// <remarks>
-        ///   Setting this property always throws a <see
-        ///   cref="NotImplementedException"/>. Reading will return the total bytes
-        ///   written out, if used in writing, or the total bytes read in, if used in
-        ///   reading.  The count may refer to compressed bytes or uncompressed bytes,
-        ///   depending on how you've used the stream.
-        /// </remarks>
-        public override long Position
-        {
-            get
-            {
-                switch (mode)
-                {
-                    case Mode.Writer:
-                        return BaseStream.Position + _gzipHeaderByteCount;
-                    case Mode.Reader:
-                        return BaseStream.Position + _gzipHeaderByteCount;
-                    default:
-                        return 0;
-                }
-            }
-
-            set => throw new NotSupportedException();
-        }
-
-        /// <summary>
-        /// Dispose the stream.
-        /// </summary>
-        /// <remarks>
-        /// This may or may not result in a <c>Close()</c> call on the captive stream.
-        /// See the doc on constructors that take a <c>leaveOpen</c> parameter for more information.
-        /// </remarks>
-        protected override void Dispose(bool disposing)
-        {
-            try
-            {
-                if (!disposed)
-                {
-                    if (disposing && (BaseStream != null))
-                    {
-                        BaseStream.Dispose();;
-                    }
-                    disposed = true;
-                }
-            }
-            finally
-            {
-                base.Dispose(disposing);
-            }
-        }
-
-        /// <summary>
-        /// Flush the stream.
-        /// </summary>
-        public override void Flush()
-        {
-            if (disposed)
-            {
-                throw new ObjectDisposedException("GZipStream");
-            }
-            BaseStream.Flush();
-        }
-
-        /// <summary>
-        ///   Read and decompress data from the source stream.
-        /// </summary>
-        ///
-        /// <remarks>
-        ///   With a <c>GZipStream</c>, decompression is done through reading.
-        /// </remarks>
-        ///
-        /// <example>
-        /// <code>
-        /// byte[] working = new byte[WORKING_BUFFER_SIZE];
-        /// using (System.IO.Stream input = System.IO.File.OpenRead(_CompressedFile))
-        /// {
-        ///     using (Stream decompressor= new Ionic.Zlib.GZipStream(input, CompressionMode.Decompress, true))
-        ///     {
-        ///         using (var output = System.IO.File.Create(_DecompressedFile))
-        ///         {
-        ///             int n;
-        ///             while ((n= decompressor.Read(working, 0, working.Length)) !=0)
-        ///             {
-        ///                 output.Write(working, 0, n);
-        ///             }
-        ///         }
-        ///     }
-        /// }
-        /// </code>
-        /// </example>
-        /// <param name="buffer">The buffer into which the decompressed data should be placed.</param>
-        /// <param name="offset">the offset within that data array to put the first byte read.</param>
-        /// <param name="count">the number of bytes to read.</param>
-        /// <returns>the number of bytes actually read</returns>
-        public override int Read(byte[] buffer, int offset, int count)
-        {
-            if (disposed)
-            {
-                throw new ObjectDisposedException("GZipStream");
-            }
-            int n = BaseStream.Read(buffer, offset, count);
-
-            // Console.WriteLine("GZipStream::Read(buffer, off({0}), c({1}) = {2}", offset, count, n);
-            // Console.WriteLine( Util.FormatByteArray(buffer, offset, n) );
-
-            if (mode == Mode.Unknown)
-            {
-                _gzipHeaderByteCount = _ReadAndValidateGzipHeader();
-                mode = Mode.Reader;
-                FileName = _GzipFileName;
-                Comment = _GzipComment;
-            }
-            return n;
-        }
-
-
-        private int _ReadAndValidateGzipHeader()
-        {
-            int totalBytesRead = 0;
-
-            // read the header on the first read
-            byte[] header = new byte[10];
-            int n = BaseStream.Read(header, 0, header.Length);
-
-            // workitem 8501: handle edge case (decompress empty stream)
-            if (n == 0)
-            {
-                return 0;
-            }
-
-            if (n != 10)
-            {
-                throw new ZlibException("Not a valid GZIP stream.");
-            }
-
-            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
-            {
-                throw new ZlibException("Bad GZIP header.");
-            }
-
-            Int32 timet = DataConverter.LittleEndian.GetInt32(header, 4);
-            _GzipMtime = UnixEpoch.AddSeconds(timet);
-            totalBytesRead += n;
-            if ((header[3] & 0x04) == 0x04)
-            {
-                // read and discard extra field
-                n = BaseStream.Read(header, 0, 2); // 2-byte length field
-                totalBytesRead += n;
-
-                Int16 extraLength = (Int16)(header[0] + header[1] * 256);
-                byte[] extra = new byte[extraLength];
-                n = BaseStream.Read(extra, 0, extra.Length);
-                if (n != extraLength)
-                {
-                    throw new ZlibException("Unexpected end-of-file reading GZIP header.");
-                }
-                totalBytesRead += n;
-            }
-            if ((header[3] & 0x08) == 0x08)
-            {
-                _GzipFileName = ReadZeroTerminatedString();
-            }
-            if ((header[3] & 0x10) == 0x010)
-            {
-                _GzipComment = ReadZeroTerminatedString();
-            }
-            if ((header[3] & 0x02) == 0x02)
-            {
-                Read(_buf1, 0, 1); // CRC16, ignore
-            }
-
-            return totalBytesRead;
-        }
-
-        private string ReadZeroTerminatedString()
-        {
-            var list = new List<byte>();
-            bool done = false;
-            do
-            {
-                // workitem 7740
-                int n = BaseStream.Read(_buf1, 0, 1);
-                if (n != 1)
-                {
-                    throw new ZlibException("Unexpected EOF reading GZIP header.");
-                }
-                if (_buf1[0] == 0)
-                {
-                    done = true;
-                }
-                else
-                {
-                    list.Add(_buf1[0]);
-                }
-            }
-            while (!done);
-            byte[] a = list.ToArray();
-            return ArchiveEncoding.Default.GetString(a, 0, a.Length);
-        }
-
-        /// <summary>
-        ///   Calling this method always throws a <see cref="NotImplementedException"/>.
-        /// </summary>
-        /// <param name="offset">irrelevant; it will always throw!</param>
-        /// <param name="origin">irrelevant; it will always throw!</param>
-        /// <returns>irrelevant!</returns>
-        public override long Seek(long offset, SeekOrigin origin)
-        {
-            throw new NotSupportedException();
-        }
-
-        /// <summary>
-        ///   Calling this method always throws a <see cref="NotImplementedException"/>.
-        /// </summary>
-        /// <param name="value">irrelevant; this method will always throw!</param>
-        public override void SetLength(long value)
-        {
-            throw new NotSupportedException();
-        }
-
-        /// <summary>
-        ///   Write data to the stream.
-        /// </summary>
-        ///
-        /// <remarks>
-        /// <para>
-        ///   If you wish to use the <c>GZipStream</c> to compress data while writing,
-        ///   you can create a <c>GZipStream</c> with <c>CompressionMode.Compress</c>, and a
-        ///   writable output stream.  Then call <c>Write()</c> on that <c>GZipStream</c>,
-        ///   providing uncompressed data as input.  The data sent to the output stream
-        ///   will be the compressed form of the data written.
-        /// </para>
-        ///
-        /// <para>
-        ///   A <c>GZipStream</c> can be used for <c>Read()</c> or <c>Write()</c>, but not
-        ///   both. Writing implies compression.  Reading implies decompression.
-        /// </para>
-        ///
-        /// </remarks>
-        /// <param name="buffer">The buffer holding data to write to the stream.</param>
-        /// <param name="offset">the offset within that data array to find the first byte to write.</param>
-        /// <param name="count">the number of bytes to write.</param>
-        public override void Write(byte[] buffer, int offset, int count)
-        {
-            if (disposed)
-            {
-                throw new ObjectDisposedException("GZipStream");
-            }
-            if (mode == Mode.Unknown)
-            {
-                // first write in compression, therefore, emit the GZIP header
-                _gzipHeaderByteCount = EmitHeader();
-                mode = Mode.Writer;
-            }
-
-            BaseStream.Write(buffer, offset, count);
-        }
-
-        #endregion
-
-        public string Comment
-        {
-            get => _GzipComment;
-            set
-            {
-                if (disposed)
-                {
-                    throw new ObjectDisposedException("GZipStream");
-                }
-                _GzipComment = value;
-            }
-        }
-
-        public string FileName
-        {
-            get => _GzipFileName;
-            set
-            {
-                if (disposed)
-                {
-                    throw new ObjectDisposedException("GZipStream");
-                }
-                _GzipFileName = value;
-                if (_GzipFileName == null)
-                {
-                    return;
-                }
-                if (_GzipFileName.IndexOf("/") != -1)
-                {
-                    _GzipFileName = _GzipFileName.Replace("/", "\\");
-                }
-                if (_GzipFileName.EndsWith("\\"))
-                {
-                    throw new InvalidOperationException("Illegal filename");
-                }
-
-                var index = _GzipFileName.IndexOf("\\");
-                if (index != -1)
-                {
-                    // trim any leading path
-                    int length = _GzipFileName.Length;
-                    int num = length;
-                    while (--num >= 0)
-                    {
-                        char c = _GzipFileName[num];
-                        if (c == '\\')
-                        {
-                            _GzipFileName = _GzipFileName.Substring(num + 1, length - num - 1);
-                        }
-                    }
-                }
-            }
-        }
-
-        private int EmitHeader()
-        {
-            byte[] commentBytes = (Comment == null) ? null : ArchiveEncoding.Default.GetBytes(Comment);
-            byte[] filenameBytes = (FileName == null) ? null : ArchiveEncoding.Default.GetBytes(FileName);
-
-            int cbLength = (Comment == null) ? 0 : commentBytes.Length + 1;
-            int fnLength = (FileName == null) ? 0 : filenameBytes.Length + 1;
-
-            int bufferLength = 10 + cbLength + fnLength;
-            var header = new byte[bufferLength];
-            int i = 0;
-
-            // ID
-            header[i++] = 0x1F;
-            header[i++] = 0x8B;
-
-            // compression method
-            header[i++] = 8;
-            byte flag = 0;
-            if (Comment != null)
-            {
-                flag ^= 0x10;
-            }
-            if (FileName != null)
-            {
-                flag ^= 0x8;
-            }
-
-            // flag
-            header[i++] = flag;
-
-            // mtime
-            if (!LastModified.HasValue)
-            {
-                LastModified = DateTime.Now;
-            }
-            TimeSpan delta = LastModified.Value - UnixEpoch;
-            var timet = (Int32)delta.TotalSeconds;
-            DataConverter.LittleEndian.PutBytes(header, i, timet);
-            i += 4;
-
-            // xflg
-            header[i++] = 0; // this field is totally useless
-
-            // OS
-            header[i++] = 0xFF; // 0xFF == unspecified
-
-            // extra field length - only if FEXTRA is set, which it is not.
-            //header[i++]= 0;
-            //header[i++]= 0;
-
-            // filename
-            if (fnLength != 0)
-            {
-                Array.Copy(filenameBytes, 0, header, i, fnLength - 1);
-                i += fnLength - 1;
-                header[i++] = 0; // terminate
-            }
-
-            // comment
-            if (cbLength != 0)
-            {
-                Array.Copy(commentBytes, 0, header, i, cbLength - 1);
-                i += cbLength - 1;
-                header[i++] = 0; // terminate
-            }
-
-            BaseStream.Write(header, 0, header.Length);
-
-            return header.Length; // bytes written
-        }
-    }
-}
-#endif

src/SharpCompress/Compressors/Deflate/GZipStream.cs

@@ -1,4 +1,3 @@
-#if NETSTANDARD1_0
 // GZipStream.cs
 // ------------------------------------------------------------------
 //
@@ -31,41 +30,45 @@ using System;
 using System.IO;
 using SharpCompress.Common;
 using SharpCompress.Converters;
+using System.Text;
 
 namespace SharpCompress.Compressors.Deflate
 {
     public class GZipStream : Stream
     {
-        internal static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        internal static readonly DateTime UNIX_EPOCH = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
         public DateTime? LastModified { get; set; }
 
-        private string comment;
-        private string fileName;
+        private string _comment;
+        private string _fileName;
 
         internal ZlibBaseStream BaseStream;
-        private bool disposed;
-        private bool firstReadDone;
-        private int headerByteCount;
+        private bool _disposed;
+        private bool _firstReadDone;
+        private int _headerByteCount;
+
+        private readonly Encoding _encoding;
 
         public GZipStream(Stream stream, CompressionMode mode)
-            : this(stream, mode, CompressionLevel.Default, false)
+            : this(stream, mode, CompressionLevel.Default, false, Encoding.UTF8)
         {
         }
 
         public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level)
-            : this(stream, mode, level, false)
+            : this(stream, mode, level, false, Encoding.UTF8)
         {
         }
 
         public GZipStream(Stream stream, CompressionMode mode, bool leaveOpen)
-            : this(stream, mode, CompressionLevel.Default, leaveOpen)
+            : this(stream, mode, CompressionLevel.Default, leaveOpen, Encoding.UTF8)
         {
         }
 
-        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
+        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen, Encoding encoding)
         {
-            BaseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.GZIP, leaveOpen);
+            BaseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.GZIP, leaveOpen, encoding);
+            _encoding = encoding;
         }
 
         #region Zlib properties
@@ -75,7 +78,7 @@ namespace SharpCompress.Compressors.Deflate
             get => (BaseStream._flushMode);
             set
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
@@ -88,7 +91,7 @@ namespace SharpCompress.Compressors.Deflate
             get => BaseStream._bufferSize;
             set
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
@@ -124,7 +127,7 @@ namespace SharpCompress.Compressors.Deflate
         {
             get
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
@@ -150,7 +153,7 @@ namespace SharpCompress.Compressors.Deflate
         {
             get
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
@@ -180,7 +183,7 @@ namespace SharpCompress.Compressors.Deflate
             {
                 if (BaseStream._streamMode == ZlibBaseStream.StreamMode.Writer)
                 {
-                    return BaseStream._z.TotalBytesOut + headerByteCount;
+                    return BaseStream._z.TotalBytesOut + _headerByteCount;
                 }
                 if (BaseStream._streamMode == ZlibBaseStream.StreamMode.Reader)
                 {
@@ -203,14 +206,14 @@ namespace SharpCompress.Compressors.Deflate
         {
             try
             {
-                if (!disposed)
+                if (!_disposed)
                 {
                     if (disposing && (BaseStream != null))
                     {
                         BaseStream.Dispose();
                         Crc32 = BaseStream.Crc32;
                     }
-                    disposed = true;
+                    _disposed = true;
                 }
             }
             finally
@@ -224,7 +227,7 @@ namespace SharpCompress.Compressors.Deflate
         /// </summary>
         public override void Flush()
         {
-            if (disposed)
+            if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
@@ -264,7 +267,7 @@ namespace SharpCompress.Compressors.Deflate
         /// <returns>the number of bytes actually read</returns>
         public override int Read(byte[] buffer, int offset, int count)
         {
-            if (disposed)
+            if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
@@ -273,9 +276,9 @@ namespace SharpCompress.Compressors.Deflate
             // Console.WriteLine("GZipStream::Read(buffer, off({0}), c({1}) = {2}", offset, count, n);
             // Console.WriteLine( Util.FormatByteArray(buffer, offset, n) );
 
-            if (!firstReadDone)
+            if (!_firstReadDone)
             {
-                firstReadDone = true;
+                _firstReadDone = true;
                 FileName = BaseStream._GzipFileName;
                 Comment = BaseStream._GzipComment;
             }
@@ -326,7 +329,7 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="count">the number of bytes to write.</param>
         public override void Write(byte[] buffer, int offset, int count)
         {
-            if (disposed)
+            if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
@@ -336,7 +339,7 @@ namespace SharpCompress.Compressors.Deflate
                 if (BaseStream._wantCompress)
                 {
                     // first write in compression, therefore, emit the GZIP header
-                    headerByteCount = EmitHeader();
+                    _headerByteCount = EmitHeader();
                 }
                 else
                 {
@@ -347,56 +350,56 @@ namespace SharpCompress.Compressors.Deflate
             BaseStream.Write(buffer, offset, count);
         }
 
-        #endregion
+        #endregion Stream methods
 
         public String Comment
         {
-            get => comment;
+            get => _comment;
             set
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                comment = value;
+                _comment = value;
             }
         }
 
         public string FileName
         {
-            get => fileName;
+            get => _fileName;
             set
             {
-                if (disposed)
+                if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                fileName = value;
-                if (fileName == null)
+                _fileName = value;
+                if (_fileName == null)
                 {
                     return;
                 }
-                if (fileName.IndexOf("/") != -1)
+                if (_fileName.IndexOf("/") != -1)
                 {
-                    fileName = fileName.Replace("/", "\\");
+                    _fileName = _fileName.Replace("/", "\\");
                 }
-                if (fileName.EndsWith("\\"))
+                if (_fileName.EndsWith("\\"))
                 {
                     throw new InvalidOperationException("Illegal filename");
                 }
 
-                var index = fileName.IndexOf("\\");
+                var index = _fileName.IndexOf("\\");
                 if (index != -1)
                 {
                     // trim any leading path
-                    int length = fileName.Length;
+                    int length = _fileName.Length;
                     int num = length;
                     while (--num >= 0)
                     {
-                        char c = fileName[num];
+                        char c = _fileName[num];
                         if (c == '\\')
                         {
-                            fileName = fileName.Substring(num + 1, length - num - 1);
+                            _fileName = _fileName.Substring(num + 1, length - num - 1);
                         }
                     }
                 }
@@ -407,8 +410,10 @@ namespace SharpCompress.Compressors.Deflate
 
         private int EmitHeader()
         {
-            byte[] commentBytes = (Comment == null) ? null : ArchiveEncoding.Default.GetBytes(Comment);
-            byte[] filenameBytes = (FileName == null) ? null : ArchiveEncoding.Default.GetBytes(FileName);
+            byte[] commentBytes = (Comment == null) ? null
+                : _encoding.GetBytes(Comment);
+            byte[] filenameBytes = (FileName == null) ? null
+                : _encoding.GetBytes(FileName);
 
             int cbLength = (Comment == null) ? 0 : commentBytes.Length + 1;
             int fnLength = (FileName == null) ? 0 : filenameBytes.Length + 1;
@@ -441,7 +446,7 @@ namespace SharpCompress.Compressors.Deflate
             {
                 LastModified = DateTime.Now;
             }
-            TimeSpan delta = LastModified.Value - UnixEpoch;
+            TimeSpan delta = LastModified.Value - UNIX_EPOCH;
             var timet = (Int32)delta.TotalSeconds;
             DataConverter.LittleEndian.PutBytes(header, i, timet);
             i += 4;
@@ -477,5 +482,4 @@ namespace SharpCompress.Compressors.Deflate
             return header.Length; // bytes written
         }
     }
-}
-#endif
+}

src/SharpCompress/Compressors/Deflate/ZlibBaseStream.cs

@@ -1,20 +1,20 @@
 // ZlibBaseStream.cs
 // ------------------------------------------------------------------
 //
-// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.  
+// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
 // All rights reserved.
 //
 // This code module is part of DotNetZip, a zipfile class library.
 //
 // ------------------------------------------------------------------
 //
-// This code is licensed under the Microsoft Public License. 
+// This code is licensed under the Microsoft Public License.
 // See the file License.txt for the license details.
 // More info on: http://dotnetzip.codeplex.com
 //
 // ------------------------------------------------------------------
 //
-// last saved (in emacs): 
+// last saved (in emacs):
 // Time-stamp: <2009-October-28 15:45:15>
 //
 // ------------------------------------------------------------------
@@ -30,6 +30,7 @@ using System.IO;
 using SharpCompress.Common;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.Converters;
+using System.Text;
 
 namespace SharpCompress.Compressors.Deflate
 {
@@ -64,6 +65,8 @@ namespace SharpCompress.Compressors.Deflate
         protected internal DateTime _GzipMtime;
         protected internal int _gzipHeaderByteCount;
 
+        private readonly Encoding _encoding;
+
         internal int Crc32
         {
             get
@@ -80,7 +83,8 @@ namespace SharpCompress.Compressors.Deflate
                               CompressionMode compressionMode,
                               CompressionLevel level,
                               ZlibStreamFlavor flavor,
-                              bool leaveOpen)
+                              bool leaveOpen,
+                              Encoding encoding)
         {
             _flushMode = FlushType.None;
 
@@ -91,6 +95,8 @@ namespace SharpCompress.Compressors.Deflate
             _flavor = flavor;
             _level = level;
 
+            _encoding = encoding;
+
             // workitem 7159
             if (flavor == ZlibStreamFlavor.GZIP)
             {
@@ -418,8 +424,8 @@ namespace SharpCompress.Compressors.Deflate
                 }
             }
             while (!done);
-            byte[] a = list.ToArray();
-            return ArchiveEncoding.Default.GetString(a, 0, a.Length);
+            byte[] buffer = list.ToArray();
+            return _encoding.GetString(buffer, 0, buffer.Length);
         }
 
         private int _ReadAndValidateGzipHeader()
@@ -528,19 +534,19 @@ namespace SharpCompress.Compressors.Deflate
             }
             if (buffer == null)
             {
-                throw new ArgumentNullException("buffer");
+                throw new ArgumentNullException(nameof(buffer));
             }
             if (count < 0)
             {
-                throw new ArgumentOutOfRangeException("count");
+                throw new ArgumentOutOfRangeException(nameof(count));
             }
             if (offset < buffer.GetLowerBound(0))
             {
-                throw new ArgumentOutOfRangeException("offset");
+                throw new ArgumentOutOfRangeException(nameof(offset));
             }
             if ((offset + count) > buffer.GetLength(0))
             {
-                throw new ArgumentOutOfRangeException("count");
+                throw new ArgumentOutOfRangeException(nameof(count));
             }
 
             int rc = 0;
@@ -593,7 +599,7 @@ namespace SharpCompress.Compressors.Deflate
             while (_z.AvailableBytesOut > 0 && !nomoreinput && rc == ZlibConstants.Z_OK);
 
             // workitem 8557
-            // is there more room in output? 
+            // is there more room in output?
             if (_z.AvailableBytesOut > 0)
             {
                 if (rc == ZlibConstants.Z_OK && _z.AvailableBytesIn == 0)

src/SharpCompress/Compressors/Deflate/ZlibStream.cs

@@ -27,6 +27,7 @@
 
 using System;
 using System.IO;
+using System.Text;
 
 namespace SharpCompress.Compressors.Deflate
 {
@@ -36,23 +37,23 @@ namespace SharpCompress.Compressors.Deflate
         private bool _disposed;
 
         public ZlibStream(Stream stream, CompressionMode mode)
-            : this(stream, mode, CompressionLevel.Default, false)
+            : this(stream, mode, CompressionLevel.Default, false, Encoding.UTF8)
         {
         }
 
         public ZlibStream(Stream stream, CompressionMode mode, CompressionLevel level)
-            : this(stream, mode, level, false)
+            : this(stream, mode, level, false, Encoding.UTF8)
         {
         }
 
         public ZlibStream(Stream stream, CompressionMode mode, bool leaveOpen)
-            : this(stream, mode, CompressionLevel.Default, leaveOpen)
+            : this(stream, mode, CompressionLevel.Default, leaveOpen, Encoding.UTF8)
         {
         }
 
-        public ZlibStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
+        public ZlibStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen, Encoding encoding)
         {
-            _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.ZLIB, leaveOpen);
+            _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.ZLIB, leaveOpen, encoding);
         }
 
         #region Zlib properties
@@ -326,6 +327,6 @@ namespace SharpCompress.Compressors.Deflate
             _baseStream.Write(buffer, offset, count);
         }
 
-        #endregion
+        #endregion System.IO.Stream methods
     }
 }

src/SharpCompress/Compressors/LZMA/BitVector.cs

@@ -58,7 +58,7 @@ namespace SharpCompress.Compressors.LZMA
             {
                 if (index < 0 || index >= Length)
                 {
-                    throw new ArgumentOutOfRangeException("index");
+                    throw new ArgumentOutOfRangeException(nameof(index));
                 }
 
                 return (mBits[index >> 5] & (1u << (index & 31))) != 0;
@@ -69,7 +69,7 @@ namespace SharpCompress.Compressors.LZMA
         {
             if (index < 0 || index >= Length)
             {
-                throw new ArgumentOutOfRangeException("index");
+                throw new ArgumentOutOfRangeException(nameof(index));
             }
 
             mBits[index >> 5] |= 1u << (index & 31);
@@ -79,7 +79,7 @@ namespace SharpCompress.Compressors.LZMA
         {
             if (index < 0 || index >= Length)
             {
-                throw new ArgumentOutOfRangeException("index");
+                throw new ArgumentOutOfRangeException(nameof(index));
             }
 
             uint bits = mBits[index >> 5];

src/SharpCompress/Compressors/LZMA/LZipStream.cs

@@ -1,5 +1,8 @@
 using System;
 using System.IO;
+using SharpCompress.Converters;
+using SharpCompress.Crypto;
+using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.LZMA
 {
@@ -14,29 +17,62 @@ namespace SharpCompress.Compressors.LZMA
     public class LZipStream : Stream
     {
         private readonly Stream stream;
+        private readonly CountingWritableSubStream rawStream;
         private bool disposed;
         private readonly bool leaveOpen;
+        private bool finished;
 
-        public LZipStream(Stream stream, CompressionMode mode)
-            : this(stream, mode, false)
-        {
-        }
+        private long writeCount;
 
-        public LZipStream(Stream stream, CompressionMode mode, bool leaveOpen)
+        public LZipStream(Stream stream, CompressionMode mode, bool leaveOpen = false)
         {
-            if (mode != CompressionMode.Decompress)
-            {
-                throw new NotImplementedException("Only LZip decompression is currently supported");
-            }
             Mode = mode;
             this.leaveOpen = leaveOpen;
-            int dictionarySize = ValidateAndReadSize(stream);
-            if (dictionarySize == 0)
+
+            if (mode == CompressionMode.Decompress)
             {
-                throw new IOException("Not an LZip stream");
+                int dSize = ValidateAndReadSize(stream);
+                if (dSize == 0)
+                {
+                    throw new IOException("Not an LZip stream");
+                }
+                byte[] properties = GetProperties(dSize);
+                this.stream = new LzmaStream(properties, stream);
+            }
+            else
+            {
+                //default
+                int dSize = 104 * 1024;
+                WriteHeaderSize(stream);
+
+                rawStream = new CountingWritableSubStream(stream);
+                this.stream = new Crc32Stream(new LzmaStream(new LzmaEncoderProperties(true, dSize), false, rawStream));
+            }
+        }
+
+        public void Finish()
+        {
+            if (!finished)
+            {
+                if (Mode == CompressionMode.Compress)
+                {
+                    var crc32Stream = (Crc32Stream)stream;
+                    crc32Stream.WrappedStream.Dispose();
+                    crc32Stream.Dispose();
+                    var compressedCount = rawStream.Count;
+                    
+                    var bytes = DataConverter.LittleEndian.GetBytes(crc32Stream.Crc);
+                    rawStream.Write(bytes, 0, bytes.Length);
+
+                    bytes = DataConverter.LittleEndian.GetBytes(writeCount);
+                    rawStream.Write(bytes, 0, bytes.Length);
+
+                    //total with headers
+                    bytes = DataConverter.LittleEndian.GetBytes(compressedCount + 6 + 20);
+                    rawStream.Write(bytes, 0, bytes.Length);
+                }
+                finished = true;
             }
-            byte[] properties = GetProperties(dictionarySize);
-            this.stream = new LzmaStream(properties, stream);
         }
 
         #region Stream methods
@@ -48,19 +84,23 @@ namespace SharpCompress.Compressors.LZMA
                 return;
             }
             disposed = true;
-            if (disposing && !leaveOpen)
+            if (disposing)
             {
-                stream.Dispose();
+                Finish();
+                if (!leaveOpen)
+                {
+                    rawStream.Dispose();
+                }
             }
         }
 
         public CompressionMode Mode { get; }
 
-        public override bool CanRead => stream.CanRead;
+        public override bool CanRead => Mode == CompressionMode.Decompress;
 
         public override bool CanSeek => false;
 
-        public override bool CanWrite => false;
+        public override bool CanWrite => Mode == CompressionMode.Compress;
 
         public override void Flush()
         {
@@ -75,20 +115,16 @@ namespace SharpCompress.Compressors.LZMA
 
         public override int Read(byte[] buffer, int offset, int count) => stream.Read(buffer, offset, count);
 
-        public override long Seek(long offset, SeekOrigin origin)
-        {
-            throw new NotSupportedException();
-        }
+        public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
 
-        public override void SetLength(long value)
-        {
-            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();
+            stream.Write(buffer, offset, count);
+            writeCount += count;
         }
+
         #endregion
 
         /// <summary>
@@ -105,7 +141,7 @@ namespace SharpCompress.Compressors.LZMA
         /// couldn't be read or it isn't a validate LZIP header, or the dictionary
         /// size if it *is* a valid LZIP file.
         /// </summary>
-        private static int ValidateAndReadSize(Stream stream)
+        public static int ValidateAndReadSize(Stream stream)
         {
             if (stream == null)
             {
@@ -131,6 +167,17 @@ namespace SharpCompress.Compressors.LZMA
             return (1 << basePower) - subtractionNumerator * (1 << (basePower - 4));
         }
 
+        public static void WriteHeaderSize(Stream stream)
+        {
+            if (stream == null)
+            {
+                throw new ArgumentNullException(nameof(stream));
+            }
+            // hard coding the dictionary size encoding
+            byte[] header = new byte[6] {(byte)'L', (byte)'Z', (byte)'I', (byte)'P', 1, 113};
+            stream.Write(header, 0, 6);
+        }
+
         /// <summary>
         /// Creates a byte array to communicate the parameters and dictionary size to LzmaStream.
         /// </summary>

src/SharpCompress/Compressors/LZMA/LzmaStream.cs

@@ -141,10 +141,7 @@ namespace SharpCompress.Compressors.LZMA
                 {
                     position = encoder.Code(null, true);
                 }
-                if (inputStream != null)
-                {
-                    inputStream.Dispose();
-                }
+                inputStream?.Dispose();
             }
             base.Dispose(disposing);
         }

src/SharpCompress/Compressors/LZMA/Utilites/Utils.cs

@@ -58,22 +58,22 @@ namespace SharpCompress.Compressors.LZMA.Utilites
         {
             if (stream == null)
             {
-                throw new ArgumentNullException("stream");
+                throw new ArgumentNullException(nameof(stream));
             }
 
             if (buffer == null)
             {
-                throw new ArgumentNullException("buffer");
+                throw new ArgumentNullException(nameof(buffer));
             }
 
             if (offset < 0 || offset > buffer.Length)
             {
-                throw new ArgumentOutOfRangeException("offset");
+                throw new ArgumentOutOfRangeException(nameof(offset));
             }
 
             if (length < 0 || length > buffer.Length - offset)
             {
-                throw new ArgumentOutOfRangeException("length");
+                throw new ArgumentOutOfRangeException(nameof(length));
             }
 
             while (length > 0)

src/SharpCompress/Compressors/PPMd/I1/Model.cs

@@ -146,12 +146,12 @@ namespace SharpCompress.Compressors.PPMd.I1
         {
             if (target == null)
             {
-                throw new ArgumentNullException("target");
+                throw new ArgumentNullException(nameof(target));
             }
 
             if (source == null)
             {
-                throw new ArgumentNullException("source");
+                throw new ArgumentNullException(nameof(source));
             }
 
             EncodeStart(properties);
@@ -235,12 +235,12 @@ namespace SharpCompress.Compressors.PPMd.I1
         {
             if (target == null)
             {
-                throw new ArgumentNullException("target");
+                throw new ArgumentNullException(nameof(target));
             }
 
             if (source == null)
             {
-                throw new ArgumentNullException("source");
+                throw new ArgumentNullException(nameof(source));
             }
 
             DecodeStart(source, properties);

src/SharpCompress/Compressors/Rar/Decode/AudioVariables.cs

@@ -7,7 +7,7 @@ namespace SharpCompress.Compressors.Rar.Decode
             Dif = new int[11];
         }
 
-        internal int[] Dif { get; private set; }
+        internal int[] Dif { get; }
         internal int ByteCount { get; set; }
         internal int D1 { get; set; }
 

src/SharpCompress/Compressors/Rar/Decode/Decode.cs

@@ -17,17 +17,17 @@ namespace SharpCompress.Compressors.Rar.Decode
         /// <summary> returns the decode Length array</summary>
         /// <returns> decodeLength
         /// </returns>
-        internal int[] DecodeLen { get; private set; }
+        internal int[] DecodeLen { get; }
 
         /// <summary> returns the decode num array</summary>
         /// <returns> decodeNum
         /// </returns>
-        internal int[] DecodeNum { get; private set; }
+        internal int[] DecodeNum { get; }
 
         /// <summary> returns the decodePos array</summary>
         /// <returns> decodePos
         /// </returns>
-        internal int[] DecodePos { get; private set; }
+        internal int[] DecodePos { get; }
 
         internal int MaxNum { get; set; }
     }

src/SharpCompress/Compressors/Rar/VM/VMPreparedCommand.cs

@@ -10,8 +10,8 @@ namespace SharpCompress.Compressors.Rar.VM
 
         internal VMCommands OpCode { get; set; }
         internal bool IsByteMode { get; set; }
-        internal VMPreparedOperand Op1 { get; private set; }
+        internal VMPreparedOperand Op1 { get; }
 
-        internal VMPreparedOperand Op2 { get; private set; }
+        internal VMPreparedOperand Op2 { get; }
     }
 }

src/SharpCompress/Compressors/Rar/VM/VMStandardFilterSignature.cs

@@ -9,10 +9,10 @@ namespace SharpCompress.Compressors.Rar.VM
             Type = type;
         }
 
-        internal int Length { get; private set; }
+        internal int Length { get; }
 
-        internal uint CRC { get; private set; }
+        internal uint CRC { get; }
 
-        internal VMStandardFilters Type { get; private set; }
+        internal VMStandardFilters Type { get; }
     }
 }

src/SharpCompress/Compressors/Xz/BinaryUtils.cs

@@ -0,0 +1,54 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public static class BinaryUtils
+    {
+        public static int ReadLittleEndianInt32(this BinaryReader reader)
+        {
+            byte[] bytes = reader.ReadBytes(4);
+            return (bytes[0] + (bytes[1] << 8) + (bytes[2] << 16) + (bytes[3] << 24));
+        }
+
+        internal static uint ReadLittleEndianUInt32(this BinaryReader reader)
+        {
+            return unchecked((uint)ReadLittleEndianInt32(reader));
+        }
+        public static int ReadLittleEndianInt32(this Stream stream)
+        {
+            byte[] bytes = new byte[4];
+            var read = stream.ReadFully(bytes);
+            if (!read)
+            {
+                throw new EndOfStreamException();
+            }
+            return (bytes[0] + (bytes[1] << 8) + (bytes[2] << 16) + (bytes[3] << 24));
+        }
+
+        internal static uint ReadLittleEndianUInt32(this Stream stream)
+        {
+            return unchecked((uint)ReadLittleEndianInt32(stream));
+        }
+
+        internal static byte[] ToBigEndianBytes(this uint uint32)
+        {
+            var result = BitConverter.GetBytes(uint32);
+
+            if (BitConverter.IsLittleEndian)
+                Array.Reverse(result);
+
+            return result;
+        }
+
+        internal static byte[] ToLittleEndianBytes(this uint uint32)
+        {
+            var result = BitConverter.GetBytes(uint32);
+
+            if (!BitConverter.IsLittleEndian)
+                Array.Reverse(result);
+
+            return result;
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/CheckType.cs

@@ -0,0 +1,10 @@
+namespace SharpCompress.Compressors.Xz
+{
+    public enum CheckType : byte
+    {
+        NONE =   0x00,
+        CRC32 =  0x01,
+        CRC64 =  0x04,
+        SHA256 = 0x0A
+    }
+}

src/SharpCompress/Compressors/Xz/Crc32.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+
+namespace SharpCompress.Compressors.Xz
+{
+    internal static class Crc32
+    {
+        public const UInt32 DefaultPolynomial = 0xedb88320u;
+        public const UInt32 DefaultSeed = 0xffffffffu;
+
+        static UInt32[] defaultTable;
+
+        public static UInt32 Compute(byte[] buffer)
+        {
+            return Compute(DefaultSeed, buffer);
+        }
+
+        public static UInt32 Compute(UInt32 seed, byte[] buffer)
+        {
+            return Compute(DefaultPolynomial, seed, buffer);
+        }
+
+        public static UInt32 Compute(UInt32 polynomial, UInt32 seed, byte[] buffer)
+        {
+            return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
+        }
+
+        static UInt32[] InitializeTable(UInt32 polynomial)
+        {
+            if (polynomial == DefaultPolynomial && defaultTable != null)
+                return defaultTable;
+
+            var createTable = new UInt32[256];
+            for (var i = 0; i < 256; i++)
+            {
+                var entry = (UInt32)i;
+                for (var j = 0; j < 8; j++)
+                    if ((entry & 1) == 1)
+                        entry = (entry >> 1) ^ polynomial;
+                    else
+                        entry = entry >> 1;
+                createTable[i] = entry;
+            }
+
+            if (polynomial == DefaultPolynomial)
+                defaultTable = createTable;
+
+            return createTable;
+        }
+
+        static UInt32 CalculateHash(UInt32[] table, UInt32 seed, IList<byte> buffer, int start, int size)
+        {
+            var crc = seed;
+            for (var i = start; i < size - start; i++)
+                crc = (crc >> 8) ^ table[buffer[i] ^ crc & 0xff];
+            return crc;
+        }
+
+    }
+}

src/SharpCompress/Compressors/Xz/Crc64.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+
+namespace SharpCompress.Compressors.Xz
+{
+    internal static class Crc64
+    {
+        public const UInt64 DefaultSeed = 0x0;
+
+        internal static UInt64[] Table;
+
+        public const UInt64 Iso3309Polynomial = 0xD800000000000000;
+
+        public static UInt64 Compute(byte[] buffer)
+        {
+            return Compute(DefaultSeed, buffer);
+        }
+
+        public static UInt64 Compute(UInt64 seed, byte[] buffer)
+        {
+            if (Table == null)
+                Table = CreateTable(Iso3309Polynomial);
+
+            return CalculateHash(seed, Table, buffer, 0, buffer.Length);
+        }
+
+        public static UInt64 CalculateHash(UInt64 seed, UInt64[] table, IList<byte> buffer, int start, int size)
+        {
+            var crc = seed;
+
+            for (var i = start; i < size; i++)
+                unchecked
+                {
+                    crc = (crc >> 8) ^ table[(buffer[i] ^ crc) & 0xff];
+                }
+
+            return crc;
+        }
+
+        public static ulong[] CreateTable(ulong polynomial)
+        {
+            var createTable = new UInt64[256];
+            for (var i = 0; i < 256; ++i)
+            {
+                var entry = (UInt64)i;
+                for (var j = 0; j < 8; ++j)
+                    if ((entry & 1) == 1)
+                        entry = (entry >> 1) ^ polynomial;
+                    else
+                        entry = entry >> 1;
+                createTable[i] = entry;
+            }
+            return createTable;
+        }
+    }
+
+}

src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz.Filters
+{
+    internal abstract class BlockFilter : ReadOnlyStream
+    {
+        public enum FilterTypes : ulong
+        {
+            DELTA = 0x03,
+            ARCH_x86_FILTER = 0x04,
+            ARCH_PowerPC_FILTER = 0x05,
+            ARCH_IA64_FILTER = 0x06,
+            ARCH_ARM_FILTER = 0x07,
+            ARCH_ARMTHUMB_FILTER = 0x08,
+            ARCH_SPARC_FILTER = 0x09,
+            LZMA2 = 0x21,
+        }
+
+        static Dictionary<FilterTypes, Type> FilterMap = new Dictionary<FilterTypes, Type>()
+        {
+            {FilterTypes.LZMA2, typeof(Lzma2Filter) }
+        };
+
+        public abstract bool AllowAsLast { get; }
+        public abstract bool AllowAsNonLast { get; }
+        public abstract bool ChangesDataSize { get; }
+
+        public BlockFilter() { }
+
+        public abstract void Init(byte[] properties);
+        public abstract void ValidateFilter();
+
+        public FilterTypes FilterType { get; set; }
+        public static BlockFilter Read(BinaryReader reader)
+        {
+            var filterType = (FilterTypes)reader.ReadXZInteger();
+            if (!FilterMap.ContainsKey(filterType))
+                throw new NotImplementedException($"Filter {filterType} has not yet been implemented");
+            var filter = Activator.CreateInstance(FilterMap[filterType]) as BlockFilter;
+
+            var sizeOfProperties = reader.ReadXZInteger();
+            if (sizeOfProperties > int.MaxValue)
+                throw new InvalidDataException("Block filter information too large");
+            byte[] properties = reader.ReadBytes((int)sizeOfProperties);
+            filter.Init(properties);
+            return filter;
+        }
+
+        public abstract void SetBaseStream(Stream stream);
+    }
+}

src/SharpCompress/Compressors/Xz/Filters/Lzma2Filter.cs

@@ -0,0 +1,54 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz.Filters
+{
+    internal class Lzma2Filter : BlockFilter
+    {
+        public override bool AllowAsLast => true;
+        public override bool AllowAsNonLast => false;
+        public override bool ChangesDataSize => true;
+
+        byte _dictionarySize;
+        public uint DictionarySize
+        {
+            get
+            {
+                if (_dictionarySize > 40)
+                    throw new OverflowException("Dictionary size greater than UInt32.Max");
+                if (_dictionarySize == 40)
+                {
+                    return uint.MaxValue;
+                }
+                int mantissa = 2 | (_dictionarySize & 1);
+                int exponent = _dictionarySize / 2 + 11;
+                return (uint)mantissa << exponent;
+            }
+        }
+
+        public override void Init(byte[] properties)
+        {
+            if (properties.Length != 1)
+                throw new InvalidDataException("LZMA properties unexpected length");
+
+            _dictionarySize = (byte)(properties[0] & 0x3F);
+            var reserved = properties[0] & 0xC0;
+            if (reserved != 0)
+                throw new InvalidDataException("Reserved bits used in LZMA properties");
+        }
+
+        public override void ValidateFilter()
+        {
+        }
+
+        public override void SetBaseStream(Stream stream)
+        {
+            BaseStream = new SharpCompress.Compressors.LZMA.LzmaStream(new[] { _dictionarySize }, stream);
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            return BaseStream.Read(buffer, offset, count);
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/MultiByteIntegers.cs

@@ -0,0 +1,32 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    internal static class MultiByteIntegers
+    {
+        public static ulong ReadXZInteger(this BinaryReader reader, int MaxBytes = 9)
+        {
+            if (MaxBytes <= 0)
+                throw new ArgumentOutOfRangeException();
+            if (MaxBytes > 9)
+                MaxBytes = 9;
+
+            byte LastByte = reader.ReadByte();
+            ulong Output = (ulong)LastByte & 0x7F;
+
+            int i = 0;
+            while ((LastByte & 0x80) != 0)
+            {
+                if (i >= MaxBytes)
+                    throw new InvalidDataException();
+                LastByte = reader.ReadByte();
+                if (LastByte == 0)
+                    throw new InvalidDataException();
+
+                Output |= ((ulong)(LastByte & 0x7F)) << (i * 7);
+            }
+            return Output;
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/ReadOnlyStream.cs

@@ -0,0 +1,44 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public abstract class ReadOnlyStream : Stream
+    {
+        public Stream BaseStream { get; protected set; }
+
+        public override bool CanRead => BaseStream.CanRead;
+
+        public override bool CanSeek => false;
+
+        public override bool CanWrite => false;
+
+        public override long Length => throw new NotSupportedException();
+
+        public override long Position
+        {
+            get => throw new NotSupportedException();
+            set => throw new NotSupportedException();
+        }
+
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZBlock.cs

@@ -0,0 +1,165 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using SharpCompress.Compressors.Xz.Filters;
+
+namespace SharpCompress.Compressors.Xz
+{
+    internal sealed class XZBlock : XZReadOnlyStream
+    {
+        public int BlockHeaderSize => (_blockHeaderSizeByte + 1) * 4;
+        public ulong? CompressedSize { get; private set; }
+        public ulong? UncompressedSize { get; private set; }
+        public Stack<BlockFilter> Filters { get; private set; } = new Stack<BlockFilter>();
+        public bool HeaderIsLoaded { get; private set; }
+        private CheckType _checkType;
+        private int _checkSize;
+        private bool _streamConnected;
+        private int _numFilters;
+        private byte _blockHeaderSizeByte;
+        private Stream _decomStream;
+        private bool _endOfStream;
+        private bool _paddingSkipped;
+        private bool _crcChecked;
+        private ulong _bytesRead;
+
+        public XZBlock(Stream stream, CheckType checkType, int checkSize) : base(stream)
+        {
+            _checkType = checkType;
+            _checkSize = checkSize;
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            int bytesRead = 0;
+            if (!HeaderIsLoaded)
+                LoadHeader();
+            if (!_streamConnected)
+                ConnectStream();
+            if (!_endOfStream)
+                bytesRead = _decomStream.Read(buffer, offset, count);
+            if (bytesRead != count)
+                _endOfStream = true;
+            if (_endOfStream && !_paddingSkipped)
+                SkipPadding();
+            if (_endOfStream && !_crcChecked)
+                CheckCrc();
+            _bytesRead += (ulong)bytesRead;
+            return bytesRead;
+        }
+
+        private void SkipPadding()
+        {
+            int padding = (int)(_bytesRead % 4);
+            if (padding > 0)
+            {
+                byte[] paddingBytes = new byte[padding];
+                BaseStream.Read(paddingBytes, 0, padding);
+                if (paddingBytes.Any(b => b != 0))
+                    throw new InvalidDataException("Padding bytes were non-null");
+            }
+            _paddingSkipped = true;
+        }
+
+        private void CheckCrc()
+        {
+            byte[] crc = new byte[_checkSize];
+            BaseStream.Read(crc, 0, _checkSize);
+            // Actually do a check (and read in the bytes
+            //   into the function throughout the stream read).
+            _crcChecked = true;
+        }
+
+        private void ConnectStream()
+        {
+            _decomStream = BaseStream;
+            while (Filters.Any())
+            {
+                var filter = Filters.Pop();
+                filter.SetBaseStream(_decomStream);
+                _decomStream = filter;
+            }
+            _streamConnected = true;
+        }
+
+        private void LoadHeader()
+        {
+            ReadHeaderSize();
+            byte[] headerCache = CacheHeader();
+
+            using (var cache = new MemoryStream(headerCache))
+            using (var cachedReader = new BinaryReader(cache))
+            {
+                cachedReader.BaseStream.Position = 1; // skip the header size byte
+                ReadBlockFlags(cachedReader);
+                ReadFilters(cachedReader);
+            }
+            HeaderIsLoaded = true;
+        }
+
+        private void ReadHeaderSize()
+        {
+            _blockHeaderSizeByte = (byte)BaseStream.ReadByte();
+            if (_blockHeaderSizeByte == 0)
+                throw new XZIndexMarkerReachedException();
+        }
+
+        private byte[] CacheHeader()
+        {
+            byte[] blockHeaderWithoutCrc = new byte[BlockHeaderSize - 4];
+            blockHeaderWithoutCrc[0] = _blockHeaderSizeByte;
+            var read = BaseStream.Read(blockHeaderWithoutCrc, 1, BlockHeaderSize - 5);
+            if (read != BlockHeaderSize - 5)
+                throw new EndOfStreamException("Reached end of stream unexectedly");
+
+            uint crc = BaseStream.ReadLittleEndianUInt32();
+            uint calcCrc = Crc32.Compute(blockHeaderWithoutCrc);
+            if (crc != calcCrc)
+                throw new InvalidDataException("Block header corrupt");
+
+            return blockHeaderWithoutCrc;
+        }
+
+        private void ReadBlockFlags(BinaryReader reader)
+        {
+            var blockFlags = reader.ReadByte();
+            _numFilters = (blockFlags & 0x03) + 1;
+            byte reserved = (byte)(blockFlags & 0x3C);
+
+            if (reserved != 0)
+                throw new InvalidDataException("Reserved bytes used, perhaps an unknown XZ implementation");
+
+            bool compressedSizePresent = (blockFlags & 0x40) != 0;
+            bool uncompressedSizePresent = (blockFlags & 0x80) != 0;
+
+            if (compressedSizePresent)
+                CompressedSize = reader.ReadXZInteger();
+            if (uncompressedSizePresent)
+                UncompressedSize = reader.ReadXZInteger();
+        }
+
+        private void ReadFilters(BinaryReader reader, long baseStreamOffset = 0)
+        {
+            int nonLastSizeChangers = 0;
+            for (int i = 0; i < _numFilters; i++)
+            {
+                var filter = BlockFilter.Read(reader);
+                if ((i + 1 == _numFilters && !filter.AllowAsLast)
+                    || (i + 1 < _numFilters && !filter.AllowAsNonLast))
+                    throw new InvalidDataException("Block Filters in bad order");
+                if (filter.ChangesDataSize && i + 1 < _numFilters)
+                    nonLastSizeChangers++;
+                filter.ValidateFilter();
+                Filters.Push(filter);
+            }
+            if (nonLastSizeChangers > 2)
+                throw new InvalidDataException("More than two non-last block filters cannot change stream size");
+
+            int blockHeaderPaddingSize = BlockHeaderSize -
+                (4 + (int)(reader.BaseStream.Position - baseStreamOffset));
+            byte[] blockHeaderPadding = reader.ReadBytes(blockHeaderPaddingSize);
+            if (!blockHeaderPadding.All(b => b == 0))
+                throw new InvalidDataException("Block header contains unknown fields");
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZFooter.cs

@@ -0,0 +1,49 @@
+using System.IO;
+using System.Linq;
+using System.Text;
+using SharpCompress.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public class XZFooter
+    {
+        private readonly BinaryReader _reader;
+        private readonly byte[] _magicBytes = new byte[] { 0x59, 0x5A };
+        public long StreamStartPosition { get; private set; }
+        public long BackwardSize { get; private set; }
+        public byte[] StreamFlags { get; private set; }
+
+        public XZFooter(BinaryReader reader)
+        {
+            _reader = reader;
+            StreamStartPosition = reader.BaseStream.Position;
+        }
+
+        public static XZFooter FromStream(Stream stream)
+        {
+            var footer = new XZFooter(new BinaryReader(new NonDisposingStream(stream), Encoding.UTF8));
+            footer.Process();
+            return footer;
+        }
+
+        public void Process()
+        {
+            uint crc = _reader.ReadLittleEndianUInt32();
+            byte[] footerBytes = _reader.ReadBytes(6);
+            uint myCrc = Crc32.Compute(footerBytes);
+            if (crc != myCrc)
+                throw new InvalidDataException("Footer corrupt");
+            using (var stream = new MemoryStream(footerBytes))
+            using (var reader = new BinaryReader(stream))
+            {
+                BackwardSize = (reader.ReadLittleEndianUInt32() + 1) * 4;
+                StreamFlags = reader.ReadBytes(2);
+            }
+            byte[] magBy = _reader.ReadBytes(2);
+            if (!Enumerable.SequenceEqual(magBy, _magicBytes))
+            {
+                throw new InvalidDataException("Magic footer missing");
+            }
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZHeader.cs

@@ -0,0 +1,55 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using SharpCompress.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public class XZHeader
+    {
+        private readonly BinaryReader _reader;
+        private readonly byte[] MagicHeader = { 0xFD, 0x37, 0x7A, 0x58, 0x5a, 0x00 };
+
+        public CheckType BlockCheckType { get; private set; }
+        public int BlockCheckSize => ((((int)BlockCheckType) + 2) / 3) * 4;
+
+        public XZHeader(BinaryReader reader)
+        {
+            _reader = reader;
+        }
+
+        public static XZHeader FromStream(Stream stream)
+        {
+            var header = new XZHeader(new BinaryReader(new NonDisposingStream(stream), Encoding.UTF8));
+            header.Process();
+            return header;
+        }
+
+        public void Process()
+        {
+            CheckMagicBytes(_reader.ReadBytes(6));
+            ProcessStreamFlags();
+        }
+
+        private void ProcessStreamFlags()
+        {
+            byte[] streamFlags = _reader.ReadBytes(2);
+            UInt32 crc = _reader.ReadLittleEndianUInt32();
+            UInt32 calcCrc = Crc32.Compute(streamFlags);
+            if (crc != calcCrc)
+                throw new InvalidDataException("Stream header corrupt");
+
+            BlockCheckType = (CheckType)(streamFlags[1] & 0x0F);
+            byte futureUse = (byte)(streamFlags[1] & 0xF0);
+            if (futureUse != 0 || streamFlags[0] != 0)
+                throw new InvalidDataException("Unknown XZ Stream Version");
+        }
+
+        private void CheckMagicBytes(byte[] header)
+        {
+            if (!Enumerable.SequenceEqual(header, MagicHeader))
+                throw new InvalidDataException("Invalid XZ Stream");
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZIndex.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using SharpCompress.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    [CLSCompliant(false)]
+    public class XZIndex
+    {
+        private readonly BinaryReader _reader;
+        public long StreamStartPosition { get; private set; }
+        public ulong NumberOfRecords { get; private set; }
+        public List<XZIndexRecord> Records { get; } = new List<XZIndexRecord>();
+
+        private bool _indexMarkerAlreadyVerified;
+
+        public XZIndex(BinaryReader reader, bool indexMarkerAlreadyVerified)
+        {
+            _reader = reader;
+            _indexMarkerAlreadyVerified = indexMarkerAlreadyVerified;
+            StreamStartPosition = reader.BaseStream.Position;
+            if (indexMarkerAlreadyVerified)
+                StreamStartPosition--;
+        }
+
+        public static XZIndex FromStream(Stream stream, bool indexMarkerAlreadyVerified)
+        {
+            var index = new XZIndex(new BinaryReader(new NonDisposingStream(stream), Encoding.UTF8), indexMarkerAlreadyVerified);
+            index.Process();
+            return index;
+        }
+
+        public void Process()
+        {
+            if (!_indexMarkerAlreadyVerified)
+                VerifyIndexMarker();
+            NumberOfRecords = _reader.ReadXZInteger();
+            for (ulong i = 0; i < NumberOfRecords; i++)
+            {
+                Records.Add(XZIndexRecord.FromBinaryReader(_reader));
+            }
+            SkipPadding();
+            VerifyCrc32();
+        }
+
+        private void VerifyIndexMarker()
+        {
+            byte marker = _reader.ReadByte();
+            if (marker != 0)
+                throw new InvalidDataException("Not an index block");
+        }
+
+        private void SkipPadding()
+        {
+            int padding = (int)(_reader.BaseStream.Position - StreamStartPosition) % 4;
+            if (padding > 0)
+            {
+                byte[] paddingBytes = _reader.ReadBytes(padding);
+                if (paddingBytes.Any(b => b != 0))
+                    throw new InvalidDataException("Padding bytes were non-null");
+            }
+        }
+
+        private void VerifyCrc32()
+        {
+            uint crc = _reader.ReadLittleEndianUInt32();
+            // TODO verify this matches
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZIndexMarkerReachedException.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public class XZIndexMarkerReachedException : Exception
+    {
+    }
+}

src/SharpCompress/Compressors/Xz/XZIndexRecord.cs

@@ -0,0 +1,22 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    [CLSCompliant(false)]
+    public class XZIndexRecord
+    {
+        public ulong UnpaddedSize { get; private set; }
+        public ulong UncompressedSize { get; private set; }
+
+        protected XZIndexRecord() { }
+
+        public static XZIndexRecord FromBinaryReader(BinaryReader br)
+        {
+            var record = new XZIndexRecord();
+            record.UnpaddedSize = br.ReadXZInteger();
+            record.UncompressedSize = br.ReadXZInteger();
+            return record;
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZReadOnlyStream.cs

@@ -0,0 +1,14 @@
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    public abstract class XZReadOnlyStream : ReadOnlyStream
+    {
+        public XZReadOnlyStream(Stream stream)
+        {
+            BaseStream = stream;
+            if (!BaseStream.CanRead)
+                throw new InvalidDataException("Must be able to read from stream");
+        }
+    }
+}

src/SharpCompress/Compressors/Xz/XZStream.cs

@@ -0,0 +1,116 @@
+using System;
+using System.IO;
+
+namespace SharpCompress.Compressors.Xz
+{
+    [CLSCompliant(false)]
+    public sealed class XZStream : XZReadOnlyStream
+    {
+        public static bool IsXZStream(Stream stream)
+        {
+            try
+            {
+                return null != XZHeader.FromStream(stream);
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+
+        private void AssertBlockCheckTypeIsSupported()
+        {
+            switch (Header.BlockCheckType)
+            {
+                case CheckType.NONE:
+                    break;
+                case CheckType.CRC32:
+                    break;
+                case CheckType.CRC64:
+                    break;
+                case CheckType.SHA256:
+                    throw new NotImplementedException();
+                default:
+                    throw new NotSupportedException("Check Type unknown to this version of decoder.");
+            }
+        }
+        public XZHeader Header { get; private set; }
+        public XZIndex Index { get; private set; }
+        public XZFooter Footer { get; private set; }
+        public bool HeaderIsRead { get; private set; }
+        private XZBlock _currentBlock;
+
+        bool _endOfStream;
+
+        public XZStream(Stream stream) : base(stream)
+        {
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            int bytesRead = 0;
+            if (_endOfStream)
+                return bytesRead;
+            if (!HeaderIsRead)
+                ReadHeader();
+            bytesRead = ReadBlocks(buffer, offset, count);
+            if (bytesRead < count)
+            {
+                _endOfStream = true;
+                ReadIndex();
+                ReadFooter();
+            }
+            return bytesRead;
+        }
+
+        private void ReadHeader()
+        {
+            Header = XZHeader.FromStream(BaseStream);
+            AssertBlockCheckTypeIsSupported();
+            HeaderIsRead = true;
+        }
+
+        private void ReadIndex()
+        {
+            Index = XZIndex.FromStream(BaseStream, true);
+            // TODO veryfy Index
+        }
+
+        private void ReadFooter()
+        {
+            Footer = XZFooter.FromStream(BaseStream);
+            // TODO verify footer
+        }
+
+        private int ReadBlocks(byte[] buffer, int offset, int count)
+        {
+            int bytesRead = 0;
+            if (_currentBlock == null)
+                NextBlock();
+            for (;;)
+            {
+                try
+                {
+                    if (bytesRead >= count)
+                        break;
+                    int remaining = count - bytesRead;
+                    int newOffset = offset + bytesRead;
+                    int justRead = _currentBlock.Read(buffer, newOffset, remaining);
+                    if (justRead < remaining)
+                        NextBlock();
+                    bytesRead += justRead;
+                }
+                catch (XZIndexMarkerReachedException)
+                {
+                    break;
+                }
+            }
+            return bytesRead;
+        }
+
+        private void NextBlock()
+        {
+            _currentBlock = new XZBlock(BaseStream, Header.BlockCheckType, Header.BlockCheckSize);
+        }
+    }
+}

src/SharpCompress/Converters/DataConverter.cs

@@ -156,7 +156,7 @@ namespace SharpCompress.Converters
         {
             if (dest == null)
             {
-                throw new ArgumentNullException("dest");
+                throw new ArgumentNullException(nameof(dest));
             }
             if (destIdx < 0 || destIdx > dest.Length - size)
             {
@@ -170,7 +170,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -195,7 +195,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -221,7 +221,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -247,7 +247,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -273,7 +273,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -299,7 +299,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -325,7 +325,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 2)
                 {
@@ -351,7 +351,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 2)
                 {
@@ -468,7 +468,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -494,7 +494,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -520,7 +520,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 8)
                 {
@@ -546,7 +546,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -572,7 +572,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -598,7 +598,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 4)
                 {
@@ -624,7 +624,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 2)
                 {
@@ -650,7 +650,7 @@ namespace SharpCompress.Converters
             {
                 if (data == null)
                 {
-                    throw new ArgumentNullException("data");
+                    throw new ArgumentNullException(nameof(data));
                 }
                 if (data.Length - index < 2)
                 {

src/SharpCompress/Crypto/Crc32Stream.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace SharpCompress.Crypto
+{
+    internal sealed class Crc32Stream : Stream
+    {
+        public const uint DefaultPolynomial = 0xedb88320u;
+        public const uint DefaultSeed = 0xffffffffu;
+
+        private static uint[] defaultTable;
+        
+        private readonly uint[] table;
+        private uint hash;
+
+        private readonly Stream stream;
+
+        public Crc32Stream(Stream stream)
+            : this(stream, DefaultPolynomial, DefaultSeed)
+        {
+        }
+
+        public Crc32Stream(Stream stream, uint polynomial, uint seed)
+        {
+            this.stream = stream;
+            table = InitializeTable(polynomial);
+            hash = seed;
+        }
+
+        public Stream WrappedStream => stream;
+
+        public override void Flush()
+        {
+            stream.Flush();
+        }
+
+        public override int Read(byte[] buffer, int offset, int count) => throw new NotSupportedException();
+
+        public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
+
+        public override void SetLength(long value) => throw new NotSupportedException();
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            stream.Write(buffer, offset, count);
+            hash = CalculateCrc(table, hash, buffer, offset, count);
+        }
+
+        public override bool CanRead => stream.CanRead;
+        public override bool CanSeek => false;
+        public override bool CanWrite => stream.CanWrite;
+        public override long Length => throw new NotSupportedException();
+        public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
+
+        public uint Crc => ~hash;
+
+        public static uint Compute(byte[] buffer)
+        {
+            return Compute(DefaultSeed, buffer);
+        }
+
+        public static uint Compute(uint seed, byte[] buffer)
+        {
+            return Compute(DefaultPolynomial, seed, buffer);
+        }
+
+        public static uint Compute(uint polynomial, uint seed, byte[] buffer)
+        {
+            return ~CalculateCrc(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
+        }
+
+        private static uint[] InitializeTable(uint polynomial)
+        {
+            if (polynomial == DefaultPolynomial && defaultTable != null)
+                return defaultTable;
+
+            var createTable = new uint[256];
+            for (var i = 0; i < 256; i++)
+            {
+                var entry = (uint)i;
+                for (var j = 0; j < 8; j++)
+                    if ((entry & 1) == 1)
+                        entry = (entry >> 1) ^ polynomial;
+                    else
+                        entry = entry >> 1;
+                createTable[i] = entry;
+            }
+
+            if (polynomial == DefaultPolynomial)
+                defaultTable = createTable;
+
+            return createTable;
+        }
+
+        private static uint CalculateCrc(uint[] table, uint crc, byte[] buffer, int offset, int count)
+        {
+            unchecked
+            {
+                for (int i = offset, end = offset + count; i < end; i++)
+                    crc = (crc >> 8) ^ table[(crc ^ buffer[i]) & 0xFF];
+            }
+            return crc;
+        }
+    }
+}

src/SharpCompress/Crypto/KeyParameter.cs

@@ -12,7 +12,7 @@ namespace Org.BouncyCastle.Crypto.Parameters
         {
             if (key == null)
             {
-                throw new ArgumentNullException("key");
+                throw new ArgumentNullException(nameof(key));
             }
 
             this.key = (byte[])key.Clone();
@@ -25,15 +25,15 @@ namespace Org.BouncyCastle.Crypto.Parameters
         {
             if (key == null)
             {
-                throw new ArgumentNullException("key");
+                throw new ArgumentNullException(nameof(key));
             }
             if (keyOff < 0 || keyOff > key.Length)
             {
-                throw new ArgumentOutOfRangeException("keyOff");
+                throw new ArgumentOutOfRangeException(nameof(keyOff));
             }
             if (keyLen < 0 || (keyOff + keyLen) > key.Length)
             {
-                throw new ArgumentOutOfRangeException("keyLen");
+                throw new ArgumentOutOfRangeException(nameof(keyLen));
             }
 
             this.key = new byte[keyLen];

src/SharpCompress/IO/CountingWritableSubStream.cs

@@ -22,6 +22,7 @@ namespace SharpCompress.IO
 
         public override void Flush()
         {
+            writableStream.Flush();
         }
 
         public override long Length => throw new NotSupportedException();

src/SharpCompress/IO/RewindableStream.cs

@@ -105,6 +105,12 @@ namespace SharpCompress.IO
 
         public override int Read(byte[] buffer, int offset, int count)
         {
+            //don't actually read if we don't really want to read anything
+            //currently a network stream bug on Windows for .NET Core
+            if (count == 0)
+            {
+                return 0;
+            }
             int read;
             if (isRewound && bufferStream.Position != bufferStream.Length)
             {

src/SharpCompress/Readers/AbstractReader.cs

@@ -139,30 +139,28 @@ namespace SharpCompress.Readers
             }
         }
 
-        private readonly byte[] skipBuffer = new byte[4096];
-
         private void Skip()
         {
-            if (!Entry.IsSolid)
+            if (ArchiveType != ArchiveType.Rar 
+                && !Entry.IsSolid 
+                && Entry.CompressedSize > 0)
             {
-                var rawStream = Entry.Parts.First().GetRawStream();
+                //not solid and has a known compressed size then we can skip raw bytes.
+                var part = Entry.Parts.First();
+                var rawStream = part.GetRawStream();
 
                 if (rawStream != null)
                 {
                     var bytesToAdvance = Entry.CompressedSize;
-                    for (var i = 0; i < bytesToAdvance / skipBuffer.Length; i++)
-                    {
-                        rawStream.Read(skipBuffer, 0, skipBuffer.Length);
-                    }
-                    rawStream.Read(skipBuffer, 0, (int)(bytesToAdvance % skipBuffer.Length));
+                    rawStream.Skip(bytesToAdvance);
+                    part.Skipped = true;
                     return;
                 }
             }
+            //don't know the size so we have to try to decompress to skip
             using (var s = OpenEntryStream())
             {
-                while (s.Read(skipBuffer, 0, skipBuffer.Length) > 0)
-                {
-                }
+                s.Skip();
             }
         }
 

src/SharpCompress/Readers/GZip/GZipReader.cs

@@ -29,11 +29,11 @@ namespace SharpCompress.Readers.GZip
             return new GZipReader(stream, options ?? new ReaderOptions());
         }
 
-        #endregion
+        #endregion Open
 
         internal override IEnumerable<GZipEntry> GetEntries(Stream stream)
         {
-            return GZipEntry.GetEntries(stream);
+            return GZipEntry.GetEntries(stream, Options);
         }
     }
 }

src/SharpCompress/Readers/ReaderFactory.cs

@@ -14,6 +14,7 @@ using SharpCompress.Readers.Rar;
 using SharpCompress.Readers.Tar;
 using SharpCompress.Readers.Zip;
 using SharpCompress.Compressors.LZMA;
+using SharpCompress.Compressors.Xz;
 
 namespace SharpCompress.Readers
 {
@@ -76,7 +77,6 @@ namespace SharpCompress.Readers
                     return new TarReader(rewindableStream, options, CompressionType.LZip);
                 }
             }
-
             rewindableStream.Rewind(false);
             if (RarArchive.IsRarFile(rewindableStream, options))
             {
@@ -90,7 +90,18 @@ namespace SharpCompress.Readers
                 rewindableStream.Rewind(true);
                 return TarReader.Open(rewindableStream, options);
             }
-            throw new InvalidOperationException("Cannot determine compressed stream type.  Supported Reader Formats: Zip, GZip, BZip2, Tar, Rar");
+            rewindableStream.Rewind(false);
+            if (XZStream.IsXZStream(rewindableStream))
+            {
+                rewindableStream.Rewind(true);
+                XZStream testStream = new XZStream(rewindableStream);
+                if (TarArchive.IsTarFile(testStream))
+                {
+                    rewindableStream.Rewind(true);
+                    return new TarReader(rewindableStream, options, CompressionType.Xz);
+                }
+            }
+            throw new InvalidOperationException("Cannot determine compressed stream type.  Supported Reader Formats: Zip, GZip, BZip2, Tar, Rar, LZip, XZ");
         }
     }
 }

src/SharpCompress/Readers/ReaderOptions.cs

@@ -8,6 +8,7 @@ namespace SharpCompress.Readers
         /// Look for RarArchive (Check for self-extracting archives or cases where RarArchive isn't at the start of the file)
         /// </summary>
         public bool LookForHeader { get; set; }
+
         public string Password { get; set; }
     }
 }

src/SharpCompress/Readers/ReaderProgress.cs

@@ -8,8 +8,8 @@ namespace SharpCompress.Readers
     public class ReaderProgress
     {
         private readonly IEntry _entry;
-        public long BytesTransferred { get; private set; }
-        public int Iterations { get; private set; }
+        public long BytesTransferred { get; }
+        public int Iterations { get; }
 
         public int PercentageRead => (int)Math.Round(PercentageReadExact);
         public double PercentageReadExact => (float)BytesTransferred / _entry.Size * 100;

src/SharpCompress/Readers/Tar/TarReader.cs

@@ -10,6 +10,7 @@ using SharpCompress.Compressors.BZip2;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.IO;
 using SharpCompress.Compressors.LZMA;
+using SharpCompress.Compressors.Xz;
 
 namespace SharpCompress.Readers.Tar
 {
@@ -43,6 +44,10 @@ namespace SharpCompress.Readers.Tar
                 {
                     return new LZipStream(stream, CompressionMode.Decompress);
                 }
+                case CompressionType.Xz:
+                {
+                    return new XZStream(stream);
+                }
                 case CompressionType.None:
                 {
                     return stream;
@@ -109,11 +114,11 @@ namespace SharpCompress.Readers.Tar
             return new TarReader(rewindableStream, options, CompressionType.None);
         }
 
-        #endregion
+        #endregion Open
 
         internal override IEnumerable<TarEntry> GetEntries(Stream stream)
         {
-            return TarEntry.GetEntries(StreamingMode.Streaming, stream, compressionType);
+            return TarEntry.GetEntries(StreamingMode.Streaming, stream, compressionType, Options.ArchiveEncoding);
         }
     }
 }

src/SharpCompress/Readers/Zip/ZipReader.cs

@@ -8,13 +8,13 @@ namespace SharpCompress.Readers.Zip
 {
     public class ZipReader : AbstractReader<ZipEntry, ZipVolume>
     {
-        private readonly StreamingZipHeaderFactory headerFactory;
+        private readonly StreamingZipHeaderFactory _headerFactory;
 
         internal ZipReader(Stream stream, ReaderOptions options)
             : base(options, ArchiveType.Zip)
         {
             Volume = new ZipVolume(stream, options);
-            headerFactory = new StreamingZipHeaderFactory(options.Password);
+            _headerFactory = new StreamingZipHeaderFactory(options.Password, options.ArchiveEncoding);
         }
 
         public override ZipVolume Volume { get; }
@@ -33,26 +33,26 @@ namespace SharpCompress.Readers.Zip
             return new ZipReader(stream, options ?? new ReaderOptions());
         }
 
-        #endregion
+        #endregion Open
 
         internal override IEnumerable<ZipEntry> GetEntries(Stream stream)
         {
-            foreach (ZipHeader h in headerFactory.ReadStreamHeader(stream))
+            foreach (ZipHeader h in _headerFactory.ReadStreamHeader(stream))
             {
                 if (h != null)
                 {
                     switch (h.ZipHeaderType)
                     {
                         case ZipHeaderType.LocalEntry:
-                        {
-                            yield return new ZipEntry(new StreamingZipFilePart(h as LocalEntryHeader,
-                                                                               stream));
-                        }
+                            {
+                                yield return new ZipEntry(new StreamingZipFilePart(h as LocalEntryHeader,
+                                                                                   stream));
+                            }
                             break;
                         case ZipHeaderType.DirectoryEnd:
-                        {
-                            yield break;
-                        }
+                            {
+                                yield break;
+                            }
                     }
                 }
             }

src/SharpCompress/SharpCompress.csproj

@@ -1,13 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
   <PropertyGroup>
     <AssemblyTitle>SharpCompress - Pure C# Decompression/Compression</AssemblyTitle>
     <NeutralLanguage>en-US</NeutralLanguage>
-    <VersionPrefix>0.16.0</VersionPrefix>
-    <AssemblyVersion>0.16.0.0</AssemblyVersion>
-    <FileVersion>0.16.0.0</FileVersion>
+    <VersionPrefix>0.18.1</VersionPrefix>
+    <AssemblyVersion>0.18.1.0</AssemblyVersion>
+    <FileVersion>0.18.1.0</FileVersion>
     <Authors>Adam Hathcock</Authors>
-    <TargetFrameworks>netstandard1.0;netstandard1.3</TargetFrameworks>
+    <TargetFrameworks Condition="'$(LibraryFrameworks)'==''">net45;net35;netstandard1.0;netstandard1.3</TargetFrameworks>
+    <TargetFrameworks Condition="'$(LibraryFrameworks)'!=''">$(LibraryFrameworks)</TargetFrameworks>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <AssemblyName>SharpCompress</AssemblyName>
@@ -15,16 +15,14 @@
     <SignAssembly>true</SignAssembly>
     <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <PackageId>SharpCompress</PackageId>
-    <PackageTags>rar;unrar;zip;unzip;bzip2;gzip;tar;7zip</PackageTags>
+    <PackageTags>rar;unrar;zip;unzip;bzip2;gzip;tar;7zip;lzip;xz</PackageTags>
     <PackageProjectUrl>https://github.com/adamhathcock/sharpcompress</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/adamhathcock/sharpcompress/blob/master/LICENSE.txt</PackageLicenseUrl>
     <GenerateAssemblyTitleAttribute>false</GenerateAssemblyTitleAttribute>
     <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
-    <Description>SharpCompress is a compression library for NET Standard 1.0  that can unrar, decompress 7zip, zip/unzip, tar/untar bzip2/unbzip2 and gzip/ungzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip is implemented.</Description>
+    <Description>SharpCompress is a compression library for NET Standard 1.0  that can unrar, decompress 7zip, decompress xz, zip/unzip, tar/untar lzip/unlzip, bzip2/unbzip2 and gzip/ungzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip is implemented.</Description>
   </PropertyGroup>
-
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard1.0' ">
     <DefineConstants>$(DefineConstants);NO_FILE;NO_CRYPTO;SILVERLIGHT</DefineConstants>
   </PropertyGroup>
-
-</Project>
+</Project>

src/SharpCompress/Utility.cs

@@ -7,7 +7,7 @@ using SharpCompress.Readers;
 namespace SharpCompress
 {
     internal static class Utility
-    {
+    {   
         public static ReadOnlyCollection<T> ToReadOnly<T>(this IEnumerable<T> items)
         {
             return new ReadOnlyCollection<T>(items.ToList());
@@ -138,7 +138,7 @@ namespace SharpCompress
 
         public static void Skip(this Stream source, long advanceAmount)
         {
-            byte[] buffer = new byte[32 * 1024];
+            byte[] buffer = GetTransferByteArray();
             int read = 0;
             int readCount = 0;
             do
@@ -162,9 +162,9 @@ namespace SharpCompress
             while (true);
         }
 
-        public static void SkipAll(this Stream source)
+        public static void Skip(this Stream source)
         {
-            byte[] buffer = new byte[32 * 1024];
+            byte[] buffer = GetTransferByteArray();
             do
             {
             }

src/SharpCompress/Writers/AbstractWriter.cs

@@ -6,29 +6,30 @@ namespace SharpCompress.Writers
 {
     public abstract class AbstractWriter : IWriter
     {
-        private bool closeStream;
         private bool isDisposed;
 
-        protected AbstractWriter(ArchiveType type)
+        protected AbstractWriter(ArchiveType type, WriterOptions writerOptions)
         {
             WriterType = type;
+            WriterOptions = writerOptions;
         }
 
-        protected void InitalizeStream(Stream stream, bool closeStream)
+        protected void InitalizeStream(Stream stream)
         {
             OutputStream = stream;
-            this.closeStream = closeStream;
         }
 
         protected Stream OutputStream { get; private set; }
 
         public ArchiveType WriterType { get; }
 
+        protected WriterOptions WriterOptions { get; }
+
         public abstract void Write(string filename, Stream source, DateTime? modificationTime);
 
         protected virtual void Dispose(bool isDisposing)
         {
-            if (isDisposing && closeStream)
+            if (isDisposing && !WriterOptions.LeaveStreamOpen)
             {
                 OutputStream.Dispose();
             }

src/SharpCompress/Writers/GZip/GZipWriter.cs

@@ -8,12 +8,15 @@ namespace SharpCompress.Writers.GZip
 {
     public class GZipWriter : AbstractWriter
     {
-        private bool wroteToStream;
+        private bool _wroteToStream;
 
-        public GZipWriter(Stream destination, bool leaveOpen = false)
-            : base(ArchiveType.GZip)
+        public GZipWriter(Stream destination, GZipWriterOptions options = null)
+            : base(ArchiveType.GZip, options ?? new GZipWriterOptions())
         {
-            InitalizeStream(new GZipStream(destination, CompressionMode.Compress, leaveOpen), !leaveOpen);
+            InitalizeStream(new GZipStream(destination, CompressionMode.Compress, 
+                                           options?.CompressionLevel ?? CompressionLevel.Default, 
+                                           WriterOptions.LeaveStreamOpen, 
+                                           WriterOptions.ArchiveEncoding.GetEncoding()));
         }
 
         protected override void Dispose(bool isDisposing)
@@ -28,7 +31,7 @@ namespace SharpCompress.Writers.GZip
 
         public override void Write(string filename, Stream source, DateTime? modificationTime)
         {
-            if (wroteToStream)
+            if (_wroteToStream)
             {
                 throw new ArgumentException("Can only write a single stream to a GZip file.");
             }
@@ -36,7 +39,7 @@ namespace SharpCompress.Writers.GZip
             stream.FileName = filename;
             stream.LastModified = modificationTime;
             source.TransferTo(stream);
-            wroteToStream = true;
+            _wroteToStream = true;
         }
     }
 }

src/SharpCompress/Writers/GZip/GZipWriterOptions.cs

@@ -0,0 +1,28 @@
+using SharpCompress.Common;
+using SharpCompress.Compressors.Deflate;
+
+namespace SharpCompress.Writers.GZip
+{
+    public class GZipWriterOptions : WriterOptions
+    {
+        public GZipWriterOptions()
+            : base(CompressionType.GZip)
+        {
+        }
+        
+        internal GZipWriterOptions(WriterOptions options)
+            : base(options.CompressionType)
+        {
+            LeaveStreamOpen = options.LeaveStreamOpen;
+            ArchiveEncoding = options.ArchiveEncoding;
+
+            var writerOptions = options as GZipWriterOptions;
+            if (writerOptions != null)
+            {
+                CompressionLevel = writerOptions.CompressionLevel;
+            }
+        }
+        
+        public CompressionLevel CompressionLevel { get; set; } = CompressionLevel.Default;
+    }
+}

src/SharpCompress/Writers/Tar/TarWriter.cs

@@ -5,13 +5,14 @@ using SharpCompress.Common.Tar.Headers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.BZip2;
 using SharpCompress.Compressors.Deflate;
+using SharpCompress.Compressors.LZMA;
 
 namespace SharpCompress.Writers.Tar
 {
     public class TarWriter : AbstractWriter
     {
         public TarWriter(Stream destination, WriterOptions options)
-            : base(ArchiveType.Tar)
+            : base(ArchiveType.Tar, options)
         {
             if (!destination.CanWrite)
             {
@@ -23,12 +24,17 @@ namespace SharpCompress.Writers.Tar
                     break;
                 case CompressionType.BZip2:
                 {
-                    destination = new BZip2Stream(destination, CompressionMode.Compress, options.LeaveStreamOpen);
+                    destination = new BZip2Stream(destination, CompressionMode.Compress, true);
                 }
                     break;
                 case CompressionType.GZip:
                 {
-                    destination = new GZipStream(destination, CompressionMode.Compress, options.LeaveStreamOpen);
+                    destination = new GZipStream(destination, CompressionMode.Compress, true);
+                }
+                    break;
+                case CompressionType.LZip:
+                {
+                    destination = new LZipStream(destination, CompressionMode.Compress, true);
                 }
                     break;
                 default:
@@ -36,7 +42,7 @@ namespace SharpCompress.Writers.Tar
                     throw new InvalidFormatException("Tar does not support compression: " + options.CompressionType);
                 }
             }
-            InitalizeStream(destination, !options.LeaveStreamOpen);
+            InitalizeStream(destination);
         }
 
         public override void Write(string filename, Stream source, DateTime? modificationTime)
@@ -66,7 +72,8 @@ namespace SharpCompress.Writers.Tar
 
             long realSize = size ?? source.Length;
 
-            TarHeader header = new TarHeader();
+            TarHeader header = new TarHeader(WriterOptions.ArchiveEncoding);
+
             header.LastModifiedTime = modificationTime ?? TarHeader.Epoch;
             header.Name = NormalizeFilename(filename);
             header.Size = realSize;
@@ -92,7 +99,19 @@ namespace SharpCompress.Writers.Tar
             {
                 PadTo512(0, true);
                 PadTo512(0, true);
-                (OutputStream as BZip2Stream)?.Finish(); // required when bzip2 compression is used
+                switch (OutputStream)
+                {
+                    case BZip2Stream b:
+                    {
+                        b.Finish();
+                        break;
+                    }
+                    case LZipStream l:
+                    {
+                        l.Finish();
+                        break;
+                    }
+                }
             }
             base.Dispose(isDisposing);
         }

src/SharpCompress/Writers/WriterFactory.cs

@@ -19,7 +19,7 @@ namespace SharpCompress.Writers
                     {
                         throw new InvalidFormatException("GZip archives only support GZip compression type.");
                     }
-                    return new GZipWriter(stream, writerOptions.LeaveStreamOpen);
+                    return new GZipWriter(stream, new GZipWriterOptions(writerOptions));
                 }
                 case ArchiveType.Zip:
                 {

src/SharpCompress/Writers/Zip/ZipCentralDirectoryEntry.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Text;
+using SharpCompress.Common;
 using SharpCompress.Common.Zip;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.Converters;
@@ -9,49 +10,60 @@ namespace SharpCompress.Writers.Zip
 {
     internal class ZipCentralDirectoryEntry
     {
-        internal string FileName { get; set; }
+        private readonly ZipCompressionMethod compression;
+        private readonly string fileName;
+        private readonly ArchiveEncoding archiveEncoding;
+
+        public ZipCentralDirectoryEntry(ZipCompressionMethod compression, string fileName, ulong headerOffset, ArchiveEncoding archiveEncoding)
+        {
+            this.compression = compression;
+            this.fileName = fileName;
+            HeaderOffset = headerOffset;
+            this.archiveEncoding = archiveEncoding;
+        }
+
         internal DateTime? ModificationTime { get; set; }
         internal string Comment { get; set; }
         internal uint Crc { get; set; }
-        internal ulong HeaderOffset { get; set; }
         internal ulong Compressed { get; set; }
         internal ulong Decompressed { get; set; }
         internal ushort Zip64HeaderOffset { get; set; }
+        internal ulong HeaderOffset { get; }
 
-        internal uint Write(Stream outputStream, ZipCompressionMethod compression)
+        internal uint Write(Stream outputStream)
         {
-            byte[] encodedFilename = Encoding.UTF8.GetBytes(FileName);
-            byte[] encodedComment = Encoding.UTF8.GetBytes(Comment);
+            byte[] encodedFilename = archiveEncoding.Encode(fileName);
+            byte[] encodedComment = archiveEncoding.Encode(Comment);
 
-			var zip64_stream = Compressed >= uint.MaxValue || Decompressed >= uint.MaxValue;
-			var zip64 = zip64_stream || HeaderOffset >= uint.MaxValue || Zip64HeaderOffset != 0;
+            var zip64_stream = Compressed >= uint.MaxValue || Decompressed >= uint.MaxValue;
+            var zip64 = zip64_stream || HeaderOffset >= uint.MaxValue || Zip64HeaderOffset != 0;
 
             var compressedvalue = zip64 ? uint.MaxValue : (uint)Compressed;
             var decompressedvalue = zip64 ? uint.MaxValue : (uint)Decompressed;
             var headeroffsetvalue = zip64 ? uint.MaxValue : (uint)HeaderOffset;
             var extralength = zip64 ? (2 + 2 + 8 + 8 + 8 + 4) : 0;
-            var version = (byte)(zip64 ? 45 : 10);
+            var version = (byte)(zip64 ? 45 : 20); // Version 20 required for deflate/encryption
 
-            HeaderFlags flags = HeaderFlags.UTF8;
+            HeaderFlags flags = Equals(archiveEncoding.GetEncoding(), Encoding.UTF8) ? HeaderFlags.UTF8 : HeaderFlags.None;
             if (!outputStream.CanSeek)
             {
                 // Cannot use data descriptors with zip64:
                 // https://blogs.oracle.com/xuemingshen/entry/is_zipinput_outputstream_handling_of
 
-				// We check that streams are not written too large in the ZipWritingStream,
-				// so this extra guard is not required, but kept to simplify changing the code
-				// once the zip64 post-data issue is resolved
+                // We check that streams are not written too large in the ZipWritingStream,
+                // so this extra guard is not required, but kept to simplify changing the code
+                // once the zip64 post-data issue is resolved
                 if (!zip64_stream)
                     flags |= HeaderFlags.UsePostDataDescriptor;
-                
+
                 if (compression == ZipCompressionMethod.LZMA)
                 {
                     flags |= HeaderFlags.Bit1; // eos marker
                 }
             }
 
-            //constant sig, then version made by, compabitility, then version to extract
-            outputStream.Write(new byte[] { 80, 75, 1, 2, 0x14, 0, version, 0 }, 0, 8);
+            //constant sig, then version made by, then version to extract
+            outputStream.Write(new byte[] { 80, 75, 1, 2, version, 0, version, 0 }, 0, 8);
 
             outputStream.Write(DataConverter.LittleEndian.GetBytes((ushort)flags), 0, 2);
             outputStream.Write(DataConverter.LittleEndian.GetBytes((ushort)compression), 0, 2); // zipping method