# Compressing a Stream

**RadZipLibrary** helps you compress a stream, for example, to send it over the internet. The library provides the `CompressedStream` class that compresses and decompresses streams.

This article covers the following topics:

* [API Overview](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compress-stream#api-overview)

* [Compressing a Stream](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compress-stream#compressing-a-stream)

* [Decompressing a Stream](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compress-stream#decompressing-a-stream)

* [CompressedStream Properties](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compress-stream#compressedstream-properties)

## API Overview

The `CompressedStream` class allows you to compress and decompress a stream. Initialize the class with one of the constructor overloads:

* `CompressedStream(Stream baseStream, StreamOperationMode mode, CompressionSettings settings)`

* `CompressedStream(Stream baseStream, StreamOperationMode mode, CompressionSettings settings, bool useCrc32, EncryptionSettings encryptionSettings)`

The parameters accepted by the constructors serve the following functions:

* `Stream baseStream`—A reference to a stream where the compressed result is written when compressing data or the compressed stream that needs to be decompressed when decompressing data.

* `StreamOperationMode mode`—Specifies the operation mode of the compressed stream. Use `Write` for compressing data and `Read` for decompressing.

* `CompressionSettings settings`—The settings used for the compression. The compression settings can be of type `DeflateSettings`, `LzmaSettings`, and `StoreSettings`. You can read more on the topic in the [Compression Settings](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compression-settings) article.

* `bool useCrc32`—Indicates whether to use CRC32 (`true`) or Adler32 (`false`) checksum algorithm.

* `EncryptionSettings encryptionSettings`—Specifies the encryption settings that are used. If a `null` value is passed, encryption is not performed. More information on the topic is available in the [Protect ZipArchive](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/protect-ziparchive) article.

## Compressing a Stream

You can create a compressed stream by initializing a new instance of the `CompressedStream` class. Pass as a parameter the stream in which the compressed data is written. Set the operation mode to `Write` and the compression settings that the operation uses.

**Example 1: Write to a compressed stream**

```C#
using (CompressedStream compressedStream = new CompressedStream(outputStream, StreamOperationMode.Write, new DeflateSettings()))
			{
				//write to compressed stream
			}
```

If you want to compress a specific stream (`inputStream`), you need to copy it to the compressed stream that you created.

**Example 2: Write a stream to a compressed stream**

```C#
using (CompressedStream compressedStream = new CompressedStream(outputStream, StreamOperationMode.Write, new DeflateSettings()))
{
	inputStream.CopyTo(compressedStream);
	compressedStream.Flush();
}
```

## Decompressing a Stream

Decompressing a stream follows the same pattern as compressing it. Create a new instance of the `CompressedStream` class and pass it the stream from which the compressed data is extracted, operation mode `Read`, and the compression settings that need to be used.

**Example 3: Decompress a stream**

```C#
using (CompressedStream compressedStream = new CompressedStream(inputStream, StreamOperationMode.Read, new DeflateSettings()))
{
	compressedStream.CopyTo(outputStream);
}
```

## CompressedStream Properties

`CompressedStream` derives from the `Stream` class and supports all its properties. It also exposes a set of properties that provide further information about the compressed stream:

* `BaseStream`—Property of type [Stream](https://learn.microsoft.com/en-us/dotnet/api/system.io.stream), which obtains the stream that is compressed.

* `Checksum`—Numeric value representing the checksum of the compressed stream.

* `CompressedSize`—The size of the compressed stream.

* `Length`—The uncompressed size of the stream.

## See Also

* [Protect ZipArchive](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/protect-ziparchive)
* [Compression Settings](https://www.telerik.com/document-processing-libraries/documentation/libraries/radziplibrary/features/compression-settings)
* [ZipLibrary Stream Compression Demo](https://demos.telerik.com/document-processing/ziplibrary/compress_stream)