详解免费开源的.NET多类型文件解压缩组件SharpZipLib（.NET组件介绍之七）

前面介绍了六种.NET组件，其中有一种组件是写文件的压缩和解压，现在介绍另一种文件的解压缩组件SharpZipLib。在这个组件介绍系列中，只为简单的介绍组件的背景和简单的应用，读者在阅读时可以结合官网的相关介绍和在本地实际操作。

相关的组件功能非常强大，在笔者的介绍中只是提及到简单的应用，需要了解更多的操作和特性，可以根据官网介绍，或者查看DLL文件的相关类和方法，以此来扩展相关的业务需要。

SharpZipLib是一个完全在C＃中为.NET平台编写的Zip，GZip，Tar和BZip2库。

一.SharpZipLib组件概述：

ziplib（SharpZipLib，以前的NZipLib）是一个完全在C＃为.NET平台编写的Zip，GZip，Tar和BZip2库。它实现为一个程序集（可安装在GAC中），因此可以轻松地集成到其他项目（任何.NET语言）中。 #ziplib的创建者这样说：“我已经将zip库移植到C＃，因为我需要gzip / zip压缩，我不想使用libzip.dll或类似的东西我想要的所有在纯C＃“。

SharpZipLib官网提供的下载操作：.NET 1.1，.NET 2.0（3.5，4.0），.NET CF 1.0，.NET CF 2.0的装配：下载237 KB，源代码和示例下载708 KB；源代码和示例下载708 KB；帮助文件下载1208 KB；

SharpZipLib是在GPL下发布，遵守开源协议。

二.SharpZipLib核心类和方法介绍：

以上简单的介绍了SharpZipLib组件的相关背景，现在具体看一下该组件的相关核心类和方法：

1.ZipOutputStream类PutNextEntry()：

public void PutNextEntry(ZipEntry entry)
{
  bool hasCrc;
  if (entry == null)
  {
    throw new ArgumentNullException("entry");
  }
  if (this.entries == null)
  {
    throw new InvalidOperationException("ZipOutputStream was finished");
  }
  if (this.curEntry != null)
  {
    this.CloseEntry();
  }
  if (this.entries.Count == 0x7fffffff)
  {
    throw new ZipException("Too many entries for Zip file");
  }
  CompressionMethod compressionMethod = entry.CompressionMethod;
  int defaultCompressionLevel = this.defaultCompressionLevel;
  entry.Flags &= 0x800;
  this.patchEntryHeader = false;
  if (entry.Size == 0L)
  {
    entry.CompressedSize = entry.Size;
    entry.Crc = 0L;
    compressionMethod = CompressionMethod.Stored;
    hasCrc = true;
  }
  else
  {
    hasCrc = (entry.Size >= 0L) && entry.HasCrc;
    if (compressionMethod == CompressionMethod.Stored)
    {
      if (!hasCrc)
      {
        if (!base.CanPatchEntries)
        {
          compressionMethod = CompressionMethod.Deflated;
          defaultCompressionLevel = 0;
        }
      }
      else
      {
        entry.CompressedSize = entry.Size;
        hasCrc = entry.HasCrc;
      }
    }
  }
  if (!hasCrc)
  {
    if (!base.CanPatchEntries)
    {
      entry.Flags |= 8;
    }
    else
    {
      this.patchEntryHeader = true;
    }
  }
  if (base.Password != null)
  {
    entry.IsCrypted = true;
    if (entry.Crc < 0L)
    {
      entry.Flags |= 8;
    }
  }
  entry.Offset = this.offset;
  entry.CompressionMethod = compressionMethod;
  this.curMethod = compressionMethod;
  this.sizePatchPos = -1L;
  if ((this.useZip64_ == UseZip64.On) || ((entry.Size < 0L) && (this.useZip64_ == UseZip64.Dynamic)))
  {
    entry.ForceZip64();
  }
  this.WriteLeInt(0x4034b50);
  this.WriteLeShort(entry.Version);
  this.WriteLeShort(entry.Flags);
  this.WriteLeShort((byte) entry.CompressionMethodForHeader);
  this.WriteLeInt((int) entry.DosTime);
  if (hasCrc)
  {
    this.WriteLeInt((int) entry.Crc);
    if (entry.LocalHeaderRequiresZip64)
    {
      this.WriteLeInt(-1);
      this.WriteLeInt(-1);
    }
    else
    {
      this.WriteLeInt(entry.IsCrypted ? (((int) entry.CompressedSize) + 12) : ((int) entry.CompressedSize));
      this.WriteLeInt((int) entry.Size);
    }
  }
  else
  {
    if (this.patchEntryHeader)
    {
      this.crcPatchPos = base.baseOutputStream_.Position;
    }
    this.WriteLeInt(0);
    if (this.patchEntryHeader)
    {
      this.sizePatchPos = base.baseOutputStream_.Position;
    }
    if (entry.LocalHeaderRequiresZip64 || this.patchEntryHeader)
    {
      this.WriteLeInt(-1);
      this.WriteLeInt(-1);
    }
    else
    {
      this.WriteLeInt(0);
      this.WriteLeInt(0);
    }
  }
  byte[] buffer = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
  if (buffer.Length > 0xffff)
  {
    throw new ZipException("Entry name too long.");
  }
  ZipExtraData extraData = new ZipExtraData(entry.ExtraData);
  if (entry.LocalHeaderRequiresZip64)
  {
    extraData.StartNewEntry();
    if (hasCrc)
    {
      extraData.AddLeLong(entry.Size);
      extraData.AddLeLong(entry.CompressedSize);
    }
    else
    {
      extraData.AddLeLong(-1L);
      extraData.AddLeLong(-1L);
    }
    extraData.AddNewEntry(1);
    if (!extraData.Find(1))
    {
      throw new ZipException("Internal error cant find extra data");
    }
    if (this.patchEntryHeader)
    {
      this.sizePatchPos = extraData.CurrentReadIndex;
    }
  }
  else
  {
    extraData.Delete(1);
  }
  if (entry.AESKeySize > 0)
  {
    AddExtraDataAES(entry, extraData);
  }
  byte[] entryData = extraData.GetEntryData();
  this.WriteLeShort(buffer.Length);
  this.WriteLeShort(entryData.Length);
  if (buffer.Length > 0)
  {
    base.baseOutputStream_.Write(buffer, 0, buffer.Length);
  }
  if (entry.LocalHeaderRequiresZip64 && this.patchEntryHeader)
  {
    this.sizePatchPos += base.baseOutputStream_.Position;
  }
  if (entryData.Length > 0)
  {
    base.baseOutputStream_.Write(entryData, 0, entryData.Length);
  }
  this.offset += (30 + buffer.Length) + entryData.Length;
  if (entry.AESKeySize > 0)
  {
    this.offset += entry.AESOverheadSize;
  }
  this.curEntry = entry;
  this.crc.Reset();
  if (compressionMethod == CompressionMethod.Deflated)
  {
    base.deflater_.Reset();
    base.deflater_.SetLevel(defaultCompressionLevel);
  }
  this.size = 0L;
  if (entry.IsCrypted)
  {
    if (entry.AESKeySize > 0)
    {
      this.WriteAESHeader(entry);
    }
    else if (entry.Crc < 0L)
    {
      this.WriteEncryptionHeader(entry.DosTime << 0x10);
    }
    else
    {
      this.WriteEncryptionHeader(entry.Crc);
    }
  }
}

2.ZipOutputStream类Finish()：

public override void Finish()
{
  if (this.entries != null)
  {
    if (this.curEntry != null)
    {
      this.CloseEntry();
    }
    long count = this.entries.Count;
    long sizeEntries = 0L;
    foreach (ZipEntry entry in this.entries)
    {
      this.WriteLeInt(0x2014b50);
      this.WriteLeShort(0x33);
      this.WriteLeShort(entry.Version);
      this.WriteLeShort(entry.Flags);
      this.WriteLeShort((short) entry.CompressionMethodForHeader);
      this.WriteLeInt((int) entry.DosTime);
      this.WriteLeInt((int) entry.Crc);
      if (entry.IsZip64Forced() || (entry.CompressedSize >= 0xffffffffL))
      {
        this.WriteLeInt(-1);
      }
      else
      {
        this.WriteLeInt((int) entry.CompressedSize);
      }
      if (entry.IsZip64Forced() || (entry.Size >= 0xffffffffL))
      {
        this.WriteLeInt(-1);
      }
      else
      {
        this.WriteLeInt((int) entry.Size);
      }
      byte[] buffer = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
      if (buffer.Length > 0xffff)
      {
        throw new ZipException("Name too long.");
      }
      ZipExtraData extraData = new ZipExtraData(entry.ExtraData);
      if (entry.CentralHeaderRequiresZip64)
      {
        extraData.StartNewEntry();
        if (entry.IsZip64Forced() || (entry.Size >= 0xffffffffL))
        {
          extraData.AddLeLong(entry.Size);
        }
        if (entry.IsZip64Forced() || (entry.CompressedSize >= 0xffffffffL))
        {
          extraData.AddLeLong(entry.CompressedSize);
        }
        if (entry.Offset >= 0xffffffffL)
        {
          extraData.AddLeLong(entry.Offset);
        }
        extraData.AddNewEntry(1);
      }
      else
      {
        extraData.Delete(1);
      }
      if (entry.AESKeySize > 0)
      {
        AddExtraDataAES(entry, extraData);
      }
      byte[] entryData = extraData.GetEntryData();
      byte[] buffer3 = (entry.Comment != null) ? ZipConstants.ConvertToArray(entry.Flags, entry.Comment) : new byte[0];
      if (buffer3.Length > 0xffff)
      {
        throw new ZipException("Comment too long.");
      }
      this.WriteLeShort(buffer.Length);
      this.WriteLeShort(entryData.Length);
      this.WriteLeShort(buffer3.Length);
      this.WriteLeShort(0);
      this.WriteLeShort(0);
      if (entry.ExternalFileAttributes != -1)
      {
        this.WriteLeInt(entry.ExternalFileAttributes);
      }
      else if (entry.IsDirectory)
      {
        this.WriteLeInt(0x10);
      }
      else
      {
        this.WriteLeInt(0);
      }
      if (entry.Offset >= 0xffffffffL)
      {
        this.WriteLeInt(-1);
      }
      else
      {
        this.WriteLeInt((int) entry.Offset);
      }
      if (buffer.Length > 0)
      {
        base.baseOutputStream_.Write(buffer, 0, buffer.Length);
      }
      if (entryData.Length > 0)
      {
        base.baseOutputStream_.Write(entryData, 0, entryData.Length);
      }
      if (buffer3.Length > 0)
      {
        base.baseOutputStream_.Write(buffer3, 0, buffer3.Length);
      }
      sizeEntries += ((0x2e + buffer.Length) + entryData.Length) + buffer3.Length;
    }
    using (ZipHelperStream stream = new ZipHelperStream(base.baseOutputStream_))
    {
      stream.WriteEndOfCentralDirectory(count, sizeEntries, this.offset, this.zipComment);
    }
    this.entries = null;
  }
}

 3.ZipEntry类Clone()：

public object Clone()
{
  ZipEntry entry = (ZipEntry) base.MemberwiseClone();
  if (this.extra != null)
  {
    entry.extra = new byte[this.extra.Length];
    Array.Copy(this.extra, 0, entry.extra, 0, this.extra.Length);
  }
  return entry;
}

 4.ZipOutputStream类Write()：

public override void Write(byte[] buffer, int offset, int count)
{
  if (this.curEntry == null)
  {
    throw new InvalidOperationException("No open entry.");
  }
  if (buffer == null)
  {
    throw new ArgumentNullException("buffer");
  }
  if (offset < 0)
  {
    throw new ArgumentOutOfRangeException("offset", "Cannot be negative");
  }
  if (count < 0)
  {
    throw new ArgumentOutOfRangeException("count", "Cannot be negative");
  }
  if ((buffer.Length - offset) < count)
  {
    throw new ArgumentException("Invalid offset/count combination");
  }
  this.crc.Update(buffer, offset, count);
  this.size += count;
  switch (this.curMethod)
  {
    case CompressionMethod.Stored:
      if (base.Password != null)
      {
        this.CopyAndEncrypt(buffer, offset, count);
      }
      else
      {
        base.baseOutputStream_.Write(buffer, offset, count);
      }
      break;

    case CompressionMethod.Deflated:
      base.Write(buffer, offset, count);
      break;
  }
}

三.SharpZipLib实例：

  1.压缩单个文件：

   /// <summary>
    /// 压缩单个文件
    /// </summary>
    /// <param name="fileToZip">要压缩的文件</param>
    /// <param name="zipedFile">压缩后的文件</param>
    /// <param name="compressionLevel">压缩等级</param>
    /// <param name="blockSize">每次写入大小</param>
    public static void ZipFile(string fileToZip, string zipedFile, int compressionLevel, int blockSize)
    {
      if (string.IsNullOrEmpty(fileToZip))
      {
        throw new ArgumentNullException(fileToZip);
      }
      if (string.IsNullOrEmpty(zipedFile))
      {
        throw new ArgumentNullException(zipedFile);
      }
      if (!File.Exists(fileToZip))
      {
        throw new FileNotFoundException("指定要压缩的文件: " + fileToZip + " 不存在!");
      }
      try
      {
        using (var zipFile = File.Create(zipedFile))
        {
          using (var zipStream = new ZipOutputStream(zipFile))
          {
            using (var streamToZip = new FileStream(fileToZip, FileMode.Open, FileAccess.Read))
            {
              var fileName = fileToZip.Substring(fileToZip.LastIndexOf("\\", StringComparison.Ordinal) + 1);
              var zipEntry = new ZipEntry(fileName);
              zipStream.PutNextEntry(zipEntry);
              zipStream.SetLevel(compressionLevel);
              var buffer = new byte[blockSize];
              try
              {
                int sizeRead;
                do
                {
                  sizeRead = streamToZip.Read(buffer, 0, buffer.Length);
                  zipStream.Write(buffer, 0, sizeRead);
                }
                while (sizeRead > 0);
              }
              catch (Exception ex)
              {
                throw new Exception(ex.Message);
              }
              streamToZip.Close();
            }
            zipStream.Finish();
            zipStream.Close();
          }
          zipFile.Close();
        }
      }
      catch (IOException ioex)
      {
        throw new IOException(ioex.Message);
      }
      catch (Exception ex)
      {
        throw new Exception(ex.Message);
      }

    }

 2. 压缩单个文件：

    /// <summary>
    /// 压缩单个文件
    /// </summary>
    /// <param name="fileToZip">要进行压缩的文件名</param>
    /// <param name="zipedFile">压缩后生成的压缩文件名</param>
    public static void ZipFile(string fileToZip, string zipedFile)
    {
      if (string.IsNullOrEmpty(fileToZip))
      {
        throw new ArgumentException(fileToZip);
      }
      if (string.IsNullOrEmpty(zipedFile))
      {
        throw new ArgumentException(zipedFile);
      }
      if (!File.Exists(fileToZip))
      {
        throw new FileNotFoundException("指定要压缩的文件: " + fileToZip + " 不存在!");
      }
      try
      {
        using (var fs = File.OpenRead(fileToZip))
        {
          var buffer = new byte[fs.Length];
          fs.Read(buffer, 0, buffer.Length);
          fs.Close();
          using (var zipFile = File.Create(zipedFile))
          {
            using (var zipStream = new ZipOutputStream(zipFile))
            {
              var fileName = fileToZip.Substring(fileToZip.LastIndexOf("\\", StringComparison.Ordinal) + 1);
              var zipEntry = new ZipEntry(fileName);
              zipStream.PutNextEntry(zipEntry);
              zipStream.SetLevel(5);
              zipStream.Write(buffer, 0, buffer.Length);
              zipStream.Finish();
              zipStream.Close();
            }
          }
        }
      }
      catch (IOException ioex)
      {
        throw new IOException(ioex.Message);
      }
      catch (Exception ex)
      {
        throw new Exception(ex.Message);
      }

    }

3.压缩多层目录：

   /// <summary>
    /// 压缩多层目录
    /// </summary>
    /// <param name="strDirectory">目录</param>
    /// <param name="zipedFile">压缩文件</param>
    public static void ZipFileDirectory(string strDirectory, string zipedFile)
    {
      if (string.IsNullOrEmpty(strDirectory))
      {
        throw new ArgumentException(strDirectory);
      }
      if (string.IsNullOrEmpty(zipedFile))
      {
        throw new ArgumentException(zipedFile);
      }
      using (var zipFile = File.Create(zipedFile))
      {
        using (var s = new ZipOutputStream(zipFile))
        {
          ZipSetp(strDirectory, s, "");
        }
      }
    }

4.递归遍历目录：

    /// <summary>
    /// 递归遍历目录
    /// </summary>
    /// <param name="strDirectory">目录</param>
    /// <param name="s">ZipOutputStream对象</param>
    /// <param name="parentPath">父路径</param>
    private static void ZipSetp(string strDirectory, ZipOutputStream s, string parentPath)
    {
      if (strDirectory[strDirectory.Length - 1] != Path.DirectorySeparatorChar)
      {
        strDirectory += Path.DirectorySeparatorChar;
      }
      var crc = new Crc32();

      var filenames = Directory.GetFileSystemEntries(strDirectory);
      try
      {
        // 遍历所有的文件和目录
        foreach (var file in filenames)
        {
          // 先当作目录处理如果存在这个目录就递归Copy该目录下面的文件
          if (Directory.Exists(file))
          {
            var pPath = parentPath;
            pPath += file.Substring(file.LastIndexOf("\\", StringComparison.Ordinal) + 1);
            pPath += "\\";
            ZipSetp(file, s, pPath);
          }
          // 否则直接压缩文件
          else
          {
            //打开压缩文件
            using (var fs = File.OpenRead(file))
            {
              var buffer = new byte[fs.Length];
              fs.Read(buffer, 0, buffer.Length);
              var fileName = parentPath + file.Substring(file.LastIndexOf("\\", StringComparison.Ordinal) + 1);
              var entry = new ZipEntry(fileName)
              {
                DateTime = DateTime.Now,
                Size = fs.Length
              };
              fs.Close();
              crc.Reset();
              crc.Update(buffer);
              entry.Crc = crc.Value;
              s.PutNextEntry(entry);
              s.Write(buffer, 0, buffer.Length);
            }
          }
        }
      }
      catch (IOException ioex)
      {
        throw new IOException(ioex.Message);
      }
      catch (Exception ex)
      {
        throw new Exception(ex.Message);
      }

    }

5.解压缩一个 zip 文件： 

    /// <summary>
    /// 解压缩一个 zip 文件。
    /// </summary>
    /// <param name="zipedFile">The ziped file.</param>
    /// <param name="strDirectory">The STR directory.</param>
    /// <param name="password">zip 文件的密码。</param>
    /// <param name="overWrite">是否覆盖已存在的文件。</param>
    public void UnZip(string zipedFile, string strDirectory, string password, bool overWrite)
    {
      if (string.IsNullOrEmpty(zipedFile))
      {
        throw new ArgumentException(zipedFile);
      }
      if (string.IsNullOrEmpty(strDirectory))
      {
        throw new ArgumentException(strDirectory);
      }
      if (string.IsNullOrEmpty(password))
      {
        throw new ArgumentException(password);
      }
      if (strDirectory == "")
      {
        strDirectory = Directory.GetCurrentDirectory();
      }
      if (!strDirectory.EndsWith("\\"))
      {
        strDirectory = strDirectory + "\\";
      }
      try
      {
        using (var s = new ZipInputStream(File.OpenRead(zipedFile)))
        {
          s.Password = password;
          ZipEntry theEntry;
          while ((theEntry = s.GetNextEntry()) != null)
          {
            var directoryName = string.Empty;
            var pathToZip = theEntry.Name;
            if (pathToZip != "")
            {
              directoryName = Path.GetDirectoryName(pathToZip) + "\\";
            }
            var fileName = Path.GetFileName(pathToZip);
            Directory.CreateDirectory(strDirectory + directoryName);
            if (fileName == "") continue;
            if ((!File.Exists(strDirectory + directoryName + fileName) || !overWrite) &&
              (File.Exists(strDirectory + directoryName + fileName))) continue;
            using (var streamWriter = File.Create(strDirectory + directoryName + fileName))
            {
              var data = new byte[2048];
              while (true)
              {
                var size = s.Read(data, 0, data.Length);

                if (size > 0)
                  streamWriter.Write(data, 0, size);
                else
                  break;
              }
              streamWriter.Close();
            }
          }

          s.Close();
        }
      }
      catch (IOException ioex)
      {
        throw new IOException(ioex.Message);
      }
      catch (Exception ex)
      {
        throw new Exception(ex.Message);
      }

    }

四.总结：

以上是对SharpZipLib组件的相关介绍，本文的讲解上比较的浅显，如果需要深入的学习可以进入官网进行详细的学习。组件的功能是很强大的，如何在项目中使用组件，完成我们在项目中需要实现的功能，这就是对每个开发者提出了要求，需要我们仔细的去考虑。

任何学习都需要我们自己去探索和思考，对于一个开发者来说，最重要的就是思考，因为在我们的职业生涯中，没有什么的重要性能够超过思考。如果有不足之处还望各位读者包含，并留言指正。