Compressing and DeCompressing a File in C#

Compressing and DeCompressing a File in C# By Cosmos Mysore Printer Friendly Version View My Articles 10 Points Methods to compress file and decompress file using System.IO.Compression Method to compress a file. public void CompressFile ( string sourceFile, string destinationFile ) { // Check File exists in the source path if ( File.Exists ( sourceFile ) == false ) throw new FileNotFoundException ( ); // Create the streams and byte arrays byte[] buffer = null; FileStream sourceStream = null; FileStream destinationStream = null; GZipStream compressedStream = null; try { // Read the bytes from the source file into a byte array sourceStream = new FileStream ( sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read ); // Read the source stream values into the buffer buffer = new byte[sourceStream.Length]; int checkCounter = sourceStream.Read ( buffer, 0, buffer.Length ); if ( checkCounter != buffer.Length ) { throw new ApplicationException ( ); } // Open the FileStream to write destinationStream = new FileStream ( destinationFile, FileMode.OpenOrCreate, FileAccess.Write ); // Create a compression stream pointing to the destiantion stream compressedStream = new GZipStream ( destinationStream, CompressionMode.Compress, true ); // Now write the compressed data to the destination file compressedStream.Write ( buffer, 0, buffer.Length ); } catch ( ApplicationException ex ) { MessageBox.Show ( ex.Message, "Error occured during compression", MessageBoxButtons.OK, MessageBoxIcon.Error ); } finally { // Close all streams if ( sourceStream != null ) sourceStream.Close ( ); if ( compressedStream != null ) compressedStream.Close ( ); if ( destinationStream != null ) destinationStream.Close ( ); } } Method to DeCompress a file. public void DecompressFile ( string sourceFile, string destinationFile ) { // Check File exists in the source path if ( File.Exists ( sourceFile ) == false ) throw new FileNotFoundException ( ); // Create the streams and byte arrays needed FileStream sourceStream = null; FileStream destinationStream = null; GZipStream decompressedStream = null; byte[] quartetBuffer = null; try { // Read in the compressed source stream sourceStream = new FileStream ( sourceFile, FileMode.Open ); // Create a compression stream pointing to the destiantion stream decompressedStream = new GZipStream ( sourceStream, CompressionMode.Decompress, true ); // Read the footer to determine the length of the destiantion file quartetBuffer = new byte[4]; int position = (int)sourceStream.Length - 4; sourceStream.Position = position; sourceStream.Read ( quartetBuffer, 0, 4 ); sourceStream.Position = 0; int checkLength = BitConverter.ToInt32 ( quartetBuffer, 0 ); byte[] buffer = new byte[checkLength + 100]; int offset = 0; int total = 0; // Read the compressed data into the buffer while ( true ) { int bytesRead = decompressedStream.Read ( buffer, offset, 100 ); if ( bytesRead == 0 ) break; offset += bytesRead; total += bytesRead; } // Now write to the destination file destinationStream = new FileStream ( destinationFile, FileMode.Create ); destinationStream.Write ( buffer, 0, total ); // Flush to clean out the buffer destinationStream.Flush ( ); } catch ( ApplicationException ex ) { MessageBox.Show ( ex.Message, "An Error occured during compression", MessageBoxButtons.OK, MessageBoxIcon.Error ); } finally { // Close all streams if ( sourceStream != null ) sourceStream.Close ( ); if ( decompressedStream != null ) decompressedStream.Close ( ); if ( destinationStream != null ) destinationStream.Close ( ); } }