using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Text;

using ICSharpCode.SharpZipLib.Zip;

namespace Unzip

{

      class UnzipCore

      {
　　　　　　　///配置为 QueueUserWorkItem 或 Task.Factory.StartNew，两者速度差不多

            public static void UnZip(string zipFullName, string targetPath)

            {

                  if (!Directory.Exists(targetPath))

                        Directory.CreateDirectory(targetPath);

                  int size = 1024;

                  byte[] data = new byte[size];

                  string fileName = null;

                  FileStream fs = null;

                  ZipInputStream zs = null;

                  List<string> files = new List<string>();

                  try

                  {

                        fs = new FileStream(zipFullName, FileMode.Open, FileAccess.ReadWrite);

                        zs = new ZipInputStream(fs);

                        ZipEntry theEntry;

                        while ((theEntry = zs.GetNextEntry()) != null)

                        {

                              fileName = theEntry.Name;

                              if (fileName.IndexOf(":") > -1)

                              {

                                    fileName = fileName.Replace(":", "_");

                              }

                              if (fileName.IndexOf("/") > -1)

                              {

                                    fileName = fileName.Replace("/", "\\");

                              }

                              if (theEntry.IsDirectory)

                              {

                                    if (!Directory.Exists(Path.Combine(targetPath, fileName)))

                                          Directory.CreateDirectory(Path.Combine(targetPath, fileName));

                              }

                              else

                              {

                                    string fullname = Path.Combine(targetPath, fileName);

                                    if (files.Count(f => f.ToLower().StartsWith(Path.GetDirectoryName(fullname).ToLower())) == 0)

                                    {

                                          Directory.CreateDirectory(Path.GetDirectoryName(fullname));

                                    }

                                    files.Add(fullname);

 　　　　　　　　　　　　　　　　　　　　 //该方式降低解压速度6倍以上

                                    //using (var ws = File.Create(fullname))

                                    //{

                                    //      size = zs.Read(data, 0, data.Length);

                                    //      while (size > 0)

                                    //      {

                                    //            ws.Write(data, 0, size);

                                    //            size = zs.Read(data, 0, data.Length);

                                    //      }

                                    //}

                                    List<byte> bytes = new List<byte>();

                                    size = zs.Read(data, 0, data.Length);

                                    while (size > 0)

                                    {

                                          bytes.AddRange(data);

                                          size = zs.Read(data, 0, data.Length);

                                    }

                                    var ws = new FileStream(fullname, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite, 1024, true);

                                    ws.BeginWrite(bytes.ToArray(), 0, bytes.Count, new AsyncCallback(EndWriteCallback), ws);

                              }

                        }

                  }

                  catch

                  {

                        throw;

                  }

                  finally

                  {

                        if (zs != null) zs.Close();

                        if (fs != null) fs.Close();

                  }

            }

            static void EndWriteCallback(IAsyncResult result)

            {

                  FileStream stream = (FileStream)result.AsyncState;

                  stream.EndWrite(result);

                  stream.Flush();

                  stream.Close();

            }

      }

}