How to compress and decompress files with Deflate in .NET C#

We saw the usage of the GZipStream object in this post. GZipStream follows the GZip compression algorithm which is actually based on DEFLATE and includes some headers. As a result GZip files are somewhat bigger than DEFLATE files.

Just like with GZip, DEFLATE compresses a single file and does not hold multiple files in a zip archive fashion. It is represented by the DeflateStream object and is used in much the same way as a GZipStream. The example code is in fact almost identical.

This is how to compress a file:

FileInfo fileToBeDeflateZipped = new FileInfo(@"c:\deflate\logfile.txt");
FileInfo deflateZipFileName = new FileInfo(string.Concat(fileToBeDeflateZipped.FullName, ".cmp"));

using (FileStream fileToBeZippedAsStream = fileToBeDeflateZipped.OpenRead())
{
	using (FileStream deflateZipTargetAsStream = deflateZipFileName.Create())
	{
		using (DeflateStream deflateZipStream = new DeflateStream(deflateZipTargetAsStream, CompressionMode.Compress))
		{
			try
			{
				fileToBeZippedAsStream.CopyTo(deflateZipStream);
			}
			catch (Exception ex)
			{
				Console.WriteLine(ex.Message);
			}
		}
	}
}

…and here’s how you can decompress a file:

using (FileStream fileToDecompressAsStream = deflateZipFileName.OpenRead())
{
	string decompressedFileName = @"c:\deflate\decompressed.txt";
	using (FileStream decompressedStream = File.Create(decompressedFileName))
	{
		using (DeflateStream decompressionStream = new DeflateStream(fileToDecompressAsStream, CompressionMode.Decompress))
		{
			try
			{
				decompressionStream.CopyTo(decompressedStream);
			}
			catch (Exception ex)
			{
				Console.WriteLine(ex.Message);
			}
		}
	}
}

Read all posts dedicated to file I/O here.