令人费解.Net C#DeflateStream问题

Question

我想知道是否有人可以解释一个令我疯狂的问题:

我正在写一个压缩解压缩测试类.为了测试它,我将数据集序列化为内存流,压缩它,解压缩并比较结果.

压缩很好,但是压缩是它碰到污垢的地方.这是解压缩功能:

    public static Stream GetUncompressedStreamCopy(Stream inStream)
    {
      Stream outStream = new MemoryStream();

      inStream.Position = 0;

      DeflateStream uncompressStream = new DeflateStream(inStream, 
        CompressionMode.Decompress, true);

      byte[] buffer = new byte[65536];

      int totalread = 0;
      int bytesread = 0;


      do {
        bytesread = uncompressStream.Read(buffer, 0, buffer.Length);
        totalread += bytesread;
        outStream.Write(buffer, 0, bytesread);
        Console.WriteLine("bytesRead: [{0}]\t outStream.Length [{1}]",
        bytesread, outStream.Length);
      } while (bytesread > 0);


      Console.WriteLine("total bytes read [{0}]", totalread);
      outStream.Flush();
      return outStream;
}

对于大小为65536的缓冲区,解压缩的流总是返回比未压缩的小一个字节.

现在这让我想到了我正在与之争斗的第二个问题.对于某些缓冲区大小,uncompressStream.Read返回0,即使仍有压缩数据需要提取.

对于这些情况,deflateStream.Read(s)只在do {}循环中返回一次然后返回一个等于buffersize的未压缩流,如果你将buffersize增加一个字节,那么一切都很好(除了丢失的字节).

缓冲区大小为65536的输出:(原始未压缩数据为207833)

bytesRead: [65536]       outStream.Length [65536]
bytesRead: [65536]       outStream.Length [131072]
bytesRead: [58472]       outStream.Length [189544]
bytesRead: [18288]       outStream.Length [207832]
bytesRead: [0]           outStream.Length [207832]
total bytes read [207832]

缓冲区189544(代码坦克的一些神奇数字)

bytesRead: [189544]      outStream.Length [189544]
bytesRead: [0]           outStream.Length [189544]
total bytes read [189544]
Unompressed stream size 189544

另请注意第三次读取buffersize 65536 ex:bytesRead:[58472]显然这也应该是65536,因为缓冲区上还有数据？

任何想法将极大的赞赏.

TIA

• 雅科

Answer 1

您应该始终在压缩流上调用Close().请注意Flush()是不够的.我怀疑因此,deflate流丢失了数据.