dotnet · carlossanlop · Mar 4, 2021 · Feb 26, 2021
diff --git a/includes/remarks/System.IO.Compression/CompressionLevel/CompressionLevel.md b/includes/remarks/System.IO.Compression/CompressionLevel/CompressionLevel.md
@@ -0,0 +1,25 @@
+Compression operations usually involve a tradeoff between the speed and the effectiveness of compression. You use the <xref:System.IO.Compression.CompressionLevel> enumeration to indicate which factor is more important in your development scenario: the time to complete the compression operation or the size of the compressed file. These values do not correspond to specific compression levels; the object that implements compression determines how to handle them.
+
+The following methods of the <xref:System.IO.Compression.DeflateStream>, <xref:System.IO.Compression.GZipStream>, <xref:System.IO.Compression.ZipArchive>, <xref:System.IO.Compression.ZipFile>, and <xref:System.IO.Compression.ZipFileExtensions> classes include a parameter named `compressionLevel` that lets you specify the compression level:
+
+-   <xref:System.IO.Compression.DeflateStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionLevel%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.DeflateStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionLevel%2CSystem.Boolean%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.GZipStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionLevel%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.GZipStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionLevel%2CSystem.Boolean%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.ZipArchive.CreateEntry%28System.String%2CSystem.IO.Compression.CompressionLevel%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.ZipFile.CreateFromDirectory%28System.String%2CSystem.String%2CSystem.IO.Compression.CompressionLevel%2CSystem.Boolean%29?displayProperty=nameWithType>
+
+-   <xref:System.IO.Compression.ZipFileExtensions.CreateEntryFromFile%28System.IO.Compression.ZipArchive%2CSystem.String%2CSystem.String%2CSystem.IO.Compression.CompressionLevel%29?displayProperty=nameWithType>
+
+## Examples
+
+The following example shows how to set the compression level when creating a zip archive by using the <xref:System.IO.Compression.ZipFile> class.
+
+[!code-csharp[System.IO.Compression.ZipFile#3](~/samples/snippets/csharp/VS_Snippets_CLR_System/system.io.compression.zipfile/cs/program3.cs#3)]
+[!code-vb[System.IO.Compression.ZipFile#3](~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.io.compression.zipfile/vb/program3.vb#3)]
+
diff --git a/...ks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionLevel_Boolean.md b/...ks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionLevel_Boolean.md
@@ -0,0 +1,10 @@
+You use this constructor when you want to specify whether compression efficiency or speed is more important for an instance of the <xref:System.IO.Compression.DeflateStream> class, and whether to leave the stream object open after disposing the <xref:System.IO.Compression.DeflateStream> object.
+
+This constructor overload uses the compression mode <xref:System.IO.Compression.CompressionMode.Compress>. To set the compression mode to another value, use the <xref:System.IO.Compression.DeflateStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionMode%29> or <xref:System.IO.Compression.DeflateStream.%23ctor%28System.IO.Stream%2CSystem.IO.Compression.CompressionMode%2CSystem.Boolean%29> overload.
+
+## Examples
+
+The following example shows how to set the compression level when creating a <xref:System.IO.Compression.DeflateStream> object and how to leave the stream open.
+
+[!code-csharp[System.IO.Compression.DeflateStream#2](~/samples/snippets/csharp/VS_Snippets_CLR_System/system.io.compression.deflatestream/cs/program2.cs#2)]
+[!code-vb[System.IO.Compression.DeflateStream#2](~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.io.compression.deflatestream/vb/program2.vb#2)]
diff --git a/...des/remarks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionMode.md b/...des/remarks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionMode.md
@@ -0,0 +1,15 @@
+By default, <xref:System.IO.Compression.DeflateStream> owns the underlying stream, so closing the stream also closes the underlying stream. Note that the state of the underlying stream can affect the usability of the stream. Also, no explicit checks are performed, so no additional exceptions are thrown when the new instance is created.
+
+If an instance of the <xref:System.IO.Compression.DeflateStream> class is created with the `mode` parameter equal to `Compress`, header information is inserted immediately. If no further action occurs, the stream appears as a valid, empty, compressed file.
+
+Using the <xref:System.IO.Compression.DeflateStream> class to compress a file larger than 4 GB raises an exception.
+
+By default, the compression level is set to <xref:System.IO.Compression.CompressionLevel.Optimal> when the compression mode is <xref:System.IO.Compression.CompressionMode.Compress>.
+
+## Examples
+
+The following example shows how to use the <xref:System.IO.Compression.DeflateStream> class to compress and decompress a file.
+
+[!code-csharp[IO.Compression.Deflate1#1](~/samples/snippets/csharp/VS_Snippets_CLR/IO.Compression.Deflate1/CS/deflatetest.cs#1)]
+[!code-vb[IO.Compression.Deflate1#1](~/samples/snippets/visualbasic/VS_Snippets_CLR/IO.Compression.Deflate1/VB/deflatetest.vb#1)]
+
diff --git a/...rks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionMode_Boolean.md b/...rks/System.IO.Compression/DeflateStream/.ctor_Stream_CompressionMode_Boolean.md
@@ -0,0 +1,14 @@
+By default, <xref:System.IO.Compression.DeflateStream> owns the underlying stream, so closing the stream also closes the underlying stream. Note that the state of the underlying stream can affect the usability of the stream. Also, no explicit checks are performed, so no additional exceptions are thrown when the new instance is created.
+
+If an instance of the <xref:System.IO.Compression.DeflateStream> class is created with the `mode` parameter equal to `Compress`, header information is inserted immediately. If no further action occurs, the stream appears as a valid, empty, compressed file.
+
+Using the <xref:System.IO.Compression.DeflateStream> class to compress a file larger than 4 GB raises an exception.
+
+By default, the compression level is set to <xref:System.IO.Compression.CompressionLevel.Optimal> when the compression mode is <xref:System.IO.Compression.CompressionMode.Compress>.
+
+## Examples
+
+The following code example shows how to use the <xref:System.IO.Compression.DeflateStream> class to compress and decompress a file.
+
+[!code-csharp[IO.Compression.Deflate1#1](~/samples/snippets/csharp/VS_Snippets_CLR/IO.Compression.Deflate1/CS/deflatetest.cs#1)]
+[!code-vb[IO.Compression.Deflate1#1](~/samples/snippets/visualbasic/VS_Snippets_CLR/IO.Compression.Deflate1/VB/deflatetest.vb#1)]
diff --git a/...IO.Compression/DeflateStream/BeginRead_Byte_Int32_Int32_AsyncCallback_Object.md b/...IO.Compression/DeflateStream/BeginRead_Byte_Int32_Int32_AsyncCallback_Object.md
@@ -0,0 +1,12 @@
+Starting with the .NET Framework 4.5, you can perform asynchronous read operations by using the <xref:System.IO.Stream.ReadAsync%2A> method. The <xref:System.IO.Compression.DeflateStream.BeginRead%2A> method is still available in the .NET Framework 4.5 to support legacy code; however, you can implement asynchronous I/O operations more easily by using the new async methods. For more information, see [Asynchronous File I/O](/dotnet/standard/io/asynchronous-file-i-o).
+
+Pass the <xref:System.IAsyncResult> return value to the <xref:System.IO.Compression.DeflateStream.EndRead%2A> method of the stream to determine how many bytes were read and to release operating system resources used for reading. You can do this either by using the same code that called <xref:System.IO.Compression.DeflateStream.BeginRead%2A> or in a callback passed to <xref:System.IO.Compression.DeflateStream.BeginRead%2A>.
+
+The current position in the stream is updated when the asynchronous read or write operation is issued, not when the I/O operation completes.
+
+Multiple simultaneous asynchronous requests render the request completion order uncertain.
+
+Use the <xref:System.IO.Compression.DeflateStream.CanRead%2A> property to determine whether the current <xref:System.IO.Compression.DeflateStream> object supports reading.
+
+If a stream is closed or you pass an invalid argument, exceptions are thrown immediately from <xref:System.IO.Compression.DeflateStream.BeginRead%2A>. Errors that occur during an asynchronous read request, such as a disk failure during the I/O request, occur on the thread pool thread and throw exceptions when calling <xref:System.IO.Compression.DeflateStream.EndRead%2A>.
+
diff --git a/...O.Compression/DeflateStream/BeginWrite_Byte_Int32_Int32_AsyncCallback_Object.md b/...O.Compression/DeflateStream/BeginWrite_Byte_Int32_Int32_AsyncCallback_Object.md
@@ -0,0 +1,11 @@
+Starting with the .NET Framework 4.5, you can perform asynchronous write operations by using the <xref:System.IO.Stream.WriteAsync%2A> method. The <xref:System.IO.Compression.DeflateStream.BeginWrite%2A> method is still available in the .NET Framework 4.5 to support legacy code; however, you can implement asynchronous I/O operations more easily by using the new async methods. For more information, see [Asynchronous File I/O](/dotnet/standard/io/asynchronous-file-i-o).
+
+Pass the <xref:System.IAsyncResult> object returned by the current method to <xref:System.IO.Compression.DeflateStream.EndWrite%2A> to ensure that the write completes and frees resources appropriately. You can do this either by using the same code that called <xref:System.IO.Compression.DeflateStream.BeginWrite%2A> or in a callback passed to <xref:System.IO.Compression.DeflateStream.BeginWrite%2A>. If an error occurs during an asynchronous write operation, an exception will not be thrown until <xref:System.IO.Compression.DeflateStream.EndWrite%2A> is called with the <xref:System.IAsyncResult> returned by this method.
+
+If a stream is writable, writing at the end of the stream expands the stream.
+
+The current position in the stream is updated when you issue the asynchronous read or write operation, not when the I/O operation completes. Multiple simultaneous asynchronous requests render the request completion order uncertain.
+
+Use the <xref:System.IO.Compression.DeflateStream.CanWrite%2A> property to determine whether the current <xref:System.IO.Compression.DeflateStream> object supports writing.
+
+If a stream is closed or you pass an invalid argument, exceptions are thrown immediately from <xref:System.IO.Compression.DeflateStream.BeginWrite%2A>. Errors that occur during an asynchronous write request, such as a disk failure during the I/O request, occur on the thread pool thread and throw exceptions when calling <xref:System.IO.Compression.DeflateStream.EndWrite%2A>.
diff --git a/includes/remarks/System.IO.Compression/DeflateStream/DeflateStream.md b/includes/remarks/System.IO.Compression/DeflateStream/DeflateStream.md
@@ -0,0 +1,15 @@
+
+This class represents the Deflate algorithm, which is an industry-standard algorithm for lossless file compression and decompression. Starting with the .NET Framework 4.5, the <xref:System.IO.Compression.DeflateStream> class uses the zlib library. As a result, it provides a better compression algorithm and, in most cases, a smaller compressed file than it provides in earlier versions of the .NET Framework.
+
+This class does not inherently provide functionality for adding files to or extracting files from zip archives. To work with zip archives, use the <xref:System.IO.Compression.ZipArchive> and the <xref:System.IO.Compression.ZipArchiveEntry> classes.
+
+The <xref:System.IO.Compression.DeflateStream> class uses the same compression algorithm as the gzip data format used by the <xref:System.IO.Compression.GZipStream> class.
+
+The compression functionality in <xref:System.IO.Compression.DeflateStream> and <xref:System.IO.Compression.GZipStream> is exposed as a stream. Data is read on a byte-by-byte basis, so it is not possible to perform multiple passes to determine the best method for compressing entire files or large blocks of data. The <xref:System.IO.Compression.DeflateStream> and <xref:System.IO.Compression.GZipStream> classes are best used on uncompressed sources of data. If the source data is already compressed, using these classes may actually increase the size of the stream.
+
+## Examples
+
+The following example shows how to use the <xref:System.IO.Compression.DeflateStream> class to compress and decompress a directory of files.
+
+[!code-csharp[IO.Compression.Deflate1#1](~/samples/snippets/csharp/VS_Snippets_CLR/IO.Compression.Deflate1/CS/deflatetest.cs#1)]
+[!code-vb[IO.Compression.Deflate1#1](~/samples/snippets/visualbasic/VS_Snippets_CLR/IO.Compression.Deflate1/VB/deflatetest.vb#1)]
diff --git a/...em.IO.Compression/GZipStream/BeginRead_Byte_Int32_Int32_AsyncCallback_Object.md b/...em.IO.Compression/GZipStream/BeginRead_Byte_Int32_Int32_AsyncCallback_Object.md
@@ -0,0 +1,18 @@
+Starting with the .NET Framework 4.5, you can perform asynchronous read operations by using the <xref:System.IO.Stream.ReadAsync%2A?displayProperty=nameWithType> method. The <xref:System.IO.Compression.GZipStream.BeginRead%2A> method is still available in .NET Framework 4.5 to support legacy code; however, you can implement asynchronous I/O operations more easily by using the new async methods. For more information, see [Asynchronous File I/O](/dotnet/standard/io/asynchronous-file-i-o).
+
+Pass the <xref:System.IAsyncResult> return value to the <xref:System.IO.Compression.GZipStream.EndRead%2A> method of the stream to determine how many bytes were read and to release operating system resources used for reading. You can do this either by using the same code that called <xref:System.IO.Compression.GZipStream.BeginRead%2A> or in a callback passed to <xref:System.IO.Compression.GZipStream.BeginRead%2A>.
+
+The current position in the stream is updated when the asynchronous read or write is issued, not when the I/O operation completes.
+
+Multiple simultaneous asynchronous requests render the request completion order uncertain.
+
+Use the <xref:System.IO.Compression.GZipStream.CanRead%2A> property to determine whether the current <xref:System.IO.Compression.GZipStream> object supports reading.
+
+If a stream is closed or you pass an invalid argument, exceptions are thrown immediately from <xref:System.IO.Compression.GZipStream.BeginRead%2A>. Errors that occur during an asynchronous read request, such as a disk failure during the I/O request, occur on the thread pool thread and throw exceptions when calling <xref:System.IO.Compression.GZipStream.EndRead%2A>.
+
+## Examples
+
+The following code example shows how to use the <xref:System.IO.Compression.GZipStream> class to compress and decompress a file.
+
+[!code-csharp[IO.Compression.GZip1#1](~/samples/snippets/csharp/VS_Snippets_CLR/IO.Compression.GZip1/CS/gziptest.cs#1)]
+[!code-vb[IO.Compression.GZip1#1](~/samples/snippets/visualbasic/VS_Snippets_CLR/IO.Compression.GZip1/VB/gziptest.vb#1)]
diff --git a/includes/remarks/System.IO.Compression/GZipStream/GZipStream.md b/includes/remarks/System.IO.Compression/GZipStream/GZipStream.md
@@ -0,0 +1,14 @@
+This class represents the gzip data format, which uses an industry-standard algorithm for lossless file compression and decompression. The format includes a cyclic redundancy check value for detecting data corruption. The gzip data format uses the same algorithm as the <xref:System.IO.Compression.DeflateStream> class, but can be extended to use other compression formats. The format can be readily implemented in a manner not covered by patents.
+
+Starting with the .NET Framework 4.5, the <xref:System.IO.Compression.DeflateStream> class uses the zlib library for compression. As a result, it provides a better compression algorithm and, in most cases, a smaller compressed file than it provides in earlier versions of the .NET Framework.
+
+Compressed <xref:System.IO.Compression.GZipStream> objects written to a file with an extension of .gz can be decompressed using many common compression tools; however, this class does not inherently provide functionality for adding files to or extracting files from zip archives.
+
+The compression functionality in <xref:System.IO.Compression.DeflateStream> and <xref:System.IO.Compression.GZipStream> is exposed as a stream. Data is read on a byte-by-byte basis, so it is not possible to perform multiple passes to determine the best method for compressing entire files or large blocks of data. The <xref:System.IO.Compression.DeflateStream> and <xref:System.IO.Compression.GZipStream> classes are best used on uncompressed sources of data. If the source data is already compressed, using these classes may actually increase the size of the stream.
+
+## Examples
+
+The following example shows how to use the <xref:System.IO.Compression.GZipStream> class to compress and decompress a directory of files.
+
+[!code-csharp[IO.Compression.GZip1#1](~/samples/snippets/csharp/VS_Snippets_CLR/IO.Compression.GZip1/CS/gziptest.cs#1)]
+[!code-vb[IO.Compression.GZip1#1](~/samples/snippets/visualbasic/VS_Snippets_CLR/IO.Compression.GZip1/VB/gziptest.vb#1)]
diff --git a/...ystem.IO.Compression/ZipArchive/.ctor_Stream_ZipArchiveMode_Boolean_Encoding.md b/...ystem.IO.Compression/ZipArchive/.ctor_Stream_ZipArchiveMode_Boolean_Encoding.md
@@ -0,0 +1,21 @@
+If the `mode` parameter is set to <xref:System.IO.Compression.ZipArchiveMode.Read>, the stream must support reading. If the `mode` parameter is set to <xref:System.IO.Compression.ZipArchiveMode.Create>, the stream must support writing. If the `mode` parameter is set to <xref:System.IO.Compression.ZipArchiveMode.Update>, the stream must support reading, writing, and seeking.
+
+When you open a zip archive file for reading and `entryNameEncoding` is set to `null`, entry names are decoded according to the following rules:
+
+-   When the language encoding flag (in the general-purpose bit flag of the local file header) is not set, the current system default code page is used to decode the entry name.
+
+-   When the language encoding flag is set, UTF-8 is used to decode the entry name.
+
+When you open a zip archive file for reading and `entryNameEncoding` is set to a value other than `null`, entry names are decoded according to the following rules:
+
+-   When the language encoding flag is not set, the specified `entryNameEncoding` is used to decode the entry name.
+
+-   When the language encoding flag is set, UTF-8 is used to decode the entry name.
+
+When you write to archive files and `entryNameEncoding` is set to `null`, entry names are encoded according to the following rules:
+
+-   For entry names that contain characters outside the ASCII range, the language encoding flag is set, and entry names are encoded by using UTF-8.
+
+-   For entry names that contain only ASCII characters, the language encoding flag is not set, and entry names are encoded by using the current system default code page.
+
+When you write to archive files and `entryNameEncoding` is set to a value other than `null`, the specified `entryNameEncoding` is used to encode the entry names into bytes. The language encoding flag (in the general-purpose bit flag of the local file header) is set only when the specified encoding is a UTF-8 encoding.