Memory Queue

using System;
using System.IO;
using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip;

namespace Yakiloo.Logging.Utilities
{
	internal static class ZipUtilities
	{
		#region Zip Methods

		/// <summary>
		/// This Method performs the actual compression sequence using the ICSharpZipLib. File are 
		/// compressed in zip format and added to the zip archive after removing explicit folder 
		/// information
		/// </summary>
		/// <param name="file"></param>
		/// <returns></returns>
		internal static string ZipFile(string fileToZip)
		{
			string zipFileName = string.Format("{0}.zip", fileToZip);

			try
			{
				byte[] buffer = ReadFileToZip(fileToZip);

				try
				{
					int fileNumber = 0;
					// We have to check whether the file exists first and then append a number to the file seeing that we don't want to overwrite
					// the file if it exists.
					while (File.Exists(zipFileName))
					{
						zipFileName = string.Format("{0}_{1}.zip", fileToZip, fileNumber++);
					}

					using (ZipOutputStream outZip = new ZipOutputStream(File.Create(zipFileName)))
					{
						outZip.SetLevel(9); // 0 - store only to 9 - means best compression
						ZipEntry entry = new ZipEntry(fileToZip.Substring(fileToZip.LastIndexOf("\\") + 1));

						entry.DateTime = DateTime.UtcNow;

						// Set Size and the CRC, because the information about the size and crc should be stored in the header 
						// if it is not set it is automatically written in the footer. (in this case size == crc == -1 in the header)
						// Some ZIP programs have problems with zip files that don't store the size and crc in the header.
						entry.Size = buffer.Length;

						Crc32 crc = new Crc32();

						crc.Reset();
						crc.Update(buffer);
						entry.Crc = crc.Value;
						outZip.PutNextEntry(entry);
						outZip.Write(buffer, 0, buffer.Length);
					}
				}
				catch
				{
					File.Delete(zipFileName);
				}
				finally
				{
					// We set the zip creation equal to the original
					if (File.Exists(zipFileName))
					{
						new FileInfo(zipFileName).CreationTime = new FileInfo(fileToZip).CreationTime;
						File.Delete(fileToZip);
					}
				}
			}
			catch
			{
				// Unable to open exclusively
			}

			return zipFileName;
		}

		private static byte[] ReadFileToZip(string fileToZip)
		{
			byte[] buffer;

			using (FileStream fileStream = File.Open(fileToZip, FileMode.Open, FileAccess.ReadWrite))
			{
				buffer = new byte[fileStream.Length];

				fileStream.Read(buffer, 0, buffer.Length);
				fileStream.Close();
			}

			return buffer;
		}

		#endregion Zip Methods
	}
}