using System;
using System.IO;

namespace ICSharpCode.SharpZipLib.GZip
{
	/// <summary>
	/// An example class to demonstrate compression and decompression of GZip streams.
	/// </summary>
	public static class GZip
	{
		/// <summary>
		/// Decompress the <paramref name="inStream">input</paramref> writing 
		/// uncompressed data to the <paramref name="outStream">output stream</paramref>
		/// </summary>
		/// <param name="inStream">The readable stream containing data to decompress.</param>
		/// <param name="outStream">The output stream to receive the decompressed data.</param>
		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
		public static void Decompress(Stream inStream, Stream outStream, bool isStreamOwner)
		{
			if (inStream == null || outStream == null) {
				throw new Exception("Null Stream");
			}

			try {
				using (GZipInputStream bzipInput = new GZipInputStream(inStream)) {
					bzipInput.IsStreamOwner = isStreamOwner;
					Core.StreamUtils.Copy(bzipInput, outStream, new byte[4096]);
				}
			} finally {
				if (isStreamOwner) {
					// inStream is closed by the GZipInputStream if stream owner
					outStream.Dispose();
				}
			}
		}

		/// <summary>
		/// Compress the <paramref name="inStream">input stream</paramref> sending 
		/// result data to <paramref name="outStream">output stream</paramref>
		/// </summary>
		/// <param name="inStream">The readable stream to compress.</param>
		/// <param name="outStream">The output stream to receive the compressed data.</param>
		/// <param name="isStreamOwner">Both streams are closed on completion if true.</param>
		/// <param name="level">Block size acts as compression level (1 to 9) with 1 giving 
		/// the lowest compression and 9 the highest.</param>
		public static void Compress(Stream inStream, Stream outStream, bool isStreamOwner, int level)
		{
			if (inStream == null || outStream == null) {
				throw new Exception("Null Stream");
			}

			try {
				using (GZipOutputStream bzipOutput = new GZipOutputStream(outStream, level)) {
					bzipOutput.IsStreamOwner = isStreamOwner;
					Core.StreamUtils.Copy(inStream, bzipOutput, new byte[4096]);
				}
			} finally {
				if (isStreamOwner) {
					// outStream is closed by the GZipOutputStream if stream owner
					inStream.Dispose();
				}
			}
		}

	}
}