Compressing a Stream
Telerik RadZipLibrary can significantly facilitate your efforts in compressing a stream, for example to send it over the internet. The library provides CompressedStream class that is designed to compress and decompress streams.
This article covers the following topics:
API Overview
CompressedStream class allows you to compress and decompress a stream. You need to initialize the class using 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 will be 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 – 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 article.
bool useCrc32: Indicates whether to use CRC32 (true) or Adler32 (false) checksum algorithm.
EncryptionSettings encryptionSettings: Specifies the encryption settings that will be used. If null value is passed, encryption is not performed. More information on the topic is available in the Protect ZipArchive article.
Compressing a Stream
You can create a compressed stream by initializing a new instance of the CompressedStream class and passing as a parameter the stream in which the compressed data will be written. You need to specify the operation mode to Wrtie and the compression settings that should be used.
Example 1: Write to compressed stream
using (CompressedStream compressedStream = new CompressedStream(outputStream, StreamOperationMode.Write, new DeflateSettings()))
{
// write to compressed stream
}
Using compressedStream As New CompressedStream(outputStream, StreamOperationMode.Write, New DeflateSettings())
' write to compressed stream
End Using
If you want to compress a specific stream (inputStream), you need to copy it to the compressed stream that you've created.
Example 2: Write stream to compressed stream
using (CompressedStream compressedStream = new CompressedStream(outputStream, StreamOperationMode.Write, new DeflateSettings()))
{
inputStream.CopyTo(compressedStream);
compressedStream.Flush();
}
Using compressedStream As New CompressedStream(outputStream, StreamOperationMode.Write, New DeflateSettings())
inputStream.CopyTo(compressedStream)
compressedStream.Flush()
End Using
Decompressing a Stream
Decompressing a stream is just as simple as compressing it. All you need to do is create new instance of the CompressedStream class and pass it the stream from which the compressed data will be extracted, operation mode Read, and the compression settings that need to be used.
Example 3: Decompressed stream
using (CompressedStream compressedStream = new CompressedStream(inputStream, StreamOperationMode.Read, new DeflateSettings()))
{
compressedStream.CopyTo(outputStream);
}
Using compressedStream As New CompressedStream(inputStream, StreamOperationMode.Read, New DeflateSettings())
compressedStream.CopyTo(outputStream)
End Using
CompressedStream Properties
CompressedStream derives from the Stream class and therefore it supports all its properties. In addition, it exposes a set of properties that provide further information about the compressed stream.
BaseStream: Property of type 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.