Failed to use GZipStream to decompress a file (without using CopyToAsync)

Question

I'm trying to to decompress a MemoryStream using ReadAsync/WriteAsync but it's not working.

int bufferSize = 8192;
using (var memoryStream = new MemoryStream())
using (var fileStream = new FileStream(destinationFilename, FileMode.Create, FileAccess.ReadWrite, FileShare.None))
{
    // ... populate the MemoryStream ...
    memoryStream.Position = 0;

    using (var gzipStream = new GZipStream(memoryStream, CompressionMode.Decompress, true))
    {
        ////await gzipStream.CopyToAsync(fileStream);

        byte[] buffer = new byte[bufferSize];

        while (await gzipStream.ReadAsync(buffer, 0, bufferSize) > 0)
        {
            await fileStream.WriteAsync(buffer, 0, bufferSize);
        }
    }

    await fileStream.FlushAsync();
}

The gzipStream.CopyToAsync works but not the other way. Why?

Thanks.

The file is not readable. If it is a MP4, VLC can open the file but there is no image or sound. — pellea, Dec 12 '17 at 09:47

score 0 · Accepted Answer · answered Dec 12 '17 at 09:47

0

ReadAsync is returning number of bytes read - you're ignoring that number. You can only WriteAsync the exact count of bytes you've read first.

answered Dec 12 '17 at 09:47

Ondrej Svejdar

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Failed to use GZipStream to decompress a file (without using CopyToAsync)

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