Relationship Oriented Programming

using System;
using System.IO;
using System.IO.Compression;
using System.Security.Cryptography;

using Clifton.Tools.Data;

using Vts.UnitTest;

namespace UnitTests
{
	[TestFixture]
	public class StreamingTests
	{
		[Test]
		public void EncryptionStreaming()
		{
			// string -> RawStreamEncoder -> Encryptor -> MemoryStream
			MemoryStream ms = new MemoryStream();									// final destination stream
			EncryptTransformer et = new EncryptTransformer(EncryptionAlgorithm.Des);
			ICryptoTransform ict = et.GetCryptoServiceProvider(null);
			CryptoStream encStream = new CryptoStream(ms, ict, CryptoStreamMode.Write);
			RawSerializer rs=new RawSerializer(encStream);						// serializer outputs to encoder
			rs.Serialize("Hello World");										// serialize
			((CryptoStream)encStream).FlushFinalBlock();						// MUST BE APPLIED!  Flush() does not output the last block.

			ms.Position=0;

			// MemoryStream -> Decryptor -> RawStreamDecoder -> string
			DecryptTransformer dt = new DecryptTransformer(EncryptionAlgorithm.Des);
			dt.IV = et.IV;
			ict = dt.GetCryptoServiceProvider(et.Key);
			CryptoStream decStream = new CryptoStream(ms, ict, CryptoStreamMode.Read);
			RawDeserializer rd=new RawDeserializer(decStream);					// Deserializes from decryptor stream
			string str=(string)rd.Deserialize(typeof(string));					// Gets the data.
			Assertion.Assert(str=="Hello World", "Unexpected return.");
		}

		[Test]
		public void CompressionStreaming()
		{
			// string -> RawStreamEncoder -> Compressor -> MemoryStream
			MemoryStream ms=new MemoryStream();									// final destination stream
			GZipStream comp = new GZipStream(ms, CompressionMode.Compress, true);		// important to be set to true!

			RawSerializer rs=new RawSerializer(comp);							// serializer outputs to compression
			rs.Serialize("Hello World");										// serialize
			comp.Close();														// outputs last part of the data

			ms.Position=0;

			// MemoryStream -> Decompressor -> RawStreamDecoder -> string
			GZipStream decomp = new GZipStream(ms, CompressionMode.Decompress);
			
			RawDeserializer rd=new RawDeserializer(decomp);				// Deserializes from decompressor stream
			string str=(string)rd.Deserialize(typeof(string));					// Gets the data.
			Assertion.Assert(str=="Hello World", "Unexpected return.");
		}

		[Test]
		public void CompressionEncryptionStreaming()
		{
			// string -> RawStreamEncoder -> Compressor -> Encryptor -> MemoryStream
			MemoryStream ms=new MemoryStream();									// final destination stream

			EncryptTransformer et = new EncryptTransformer(EncryptionAlgorithm.Des);
			ICryptoTransform ict = et.GetCryptoServiceProvider(null);
			CryptoStream encStream = new CryptoStream(ms, ict, CryptoStreamMode.Write);

			GZipStream comp = new GZipStream(encStream, CompressionMode.Compress, true);		// important to be set to true!

			RawSerializer rs = new RawSerializer(comp);							// serializer outputs to compression
			rs.Serialize("Hello World");										// serialize
			comp.Close();														// must close to get final bytes
			((CryptoStream)encStream).FlushFinalBlock();						// MUST BE APPLIED!  Flush() does not output the last block.

			// Reset the position and read the stream back in.
			ms.Position=0;

			// MemoryStream -> Decryptor -> Decompressor -> RawStreamDecoder -> string
			DecryptTransformer dt = new DecryptTransformer(EncryptionAlgorithm.Des);
			dt.IV = et.IV;
			ict = dt.GetCryptoServiceProvider(et.Key);
			CryptoStream decStream = new CryptoStream(ms, ict, CryptoStreamMode.Read);

			GZipStream decomp = new GZipStream(decStream, CompressionMode.Decompress);

			RawDeserializer rd = new RawDeserializer(decomp);					// Deserializes from decompressor stream

			string str=(string)rd.Deserialize(typeof(string));					// Gets the data.
			Assertion.Assert(str=="Hello World", "Unexpected return.");
		}

	}
}