c# - 不支持写入压缩流。使用 System.IO.GZipStream

Question

尝试使用 .NET 框架中包含的 GZipStream 类解压缩 (.gz) 文件时出现异常。我正在使用 MSDN 文档。这是异常(exception):

Writing to the compression stream is not supported.

这是应用程序源:

 try
 {
     var infile = new FileStream(@"C:\TarDecomp\TarDecomp\TarDecomp\bin\Debug\nick_blah-2008.tar.gz", FileMode.Open, FileAccess.Read, FileShare.Read);
     byte[] buffer = new byte[infile.Length];
     // Read the file to ensure it is readable.
     int count = infile.Read(buffer, 0, buffer.Length);
     if (count != buffer.Length)
     {
         infile.Close();
         Console.WriteLine("Test Failed: Unable to read data from file");
         return;
     }
     infile.Close();
     MemoryStream ms = new MemoryStream();
     // Use the newly created memory stream for the compressed data.
     GZipStream compressedzipStream = new GZipStream(ms, CompressionMode.Decompress, true);
     Console.WriteLine("Decompression");
     compressedzipStream.Write(buffer, 0, buffer.Length); //<<Throws error here
     // Close the stream.
     compressedzipStream.Close();
     Console.WriteLine("Original size: {0}, Compressed size: {1}", buffer.Length, ms.Length);
} catch {...}

在 compressedZipStream.write() 中抛出异常。

有什么想法吗？这个异常告诉我什么？

Answer 1

它告诉你，你应该调用Read而不是Write，因为它是解压!此外，内存流应该用数据构造，或者更确切地说，您应该将文件流直接传递给 GZipStream 构造函数。

应该如何完成的示例(还没有尝试编译它):

Stream inFile = new FileStream(@"C:\TarDecomp\TarDecomp\TarDecomp\bin\Debug\nick_blah-2008.tar.gz", FileMode.Open, FileAccess.Read, FileShare.Read);
Stream decodedStream = new MemoryStream();
byte[] buffer = new byte[4096];

using (Stream inGzipStream = new GZipStream(inFile, CompressionMode.Decompress))
{
    int bytesRead;
    while ((bytesRead = inGzipStream.Read(buffer, 0, buffer.Length)) > 0)
        decodedStream.Write(buffer, 0, bytesRead);
}

// Now decodedStream contains the decoded data