CODEWITHSUNDEEP
c#deflatestream
pepr
pepr

Reputation: 20794

Efficient way to store the DeflateStream result to `byte[]`?

I am reading the varbinary(MAX) from the SQL server table into the byte[] content variable. Then the DeflateStream is used to unpack the content. The final goal is to assign the unpacked content to another byte[] array, and then store it into the SQL table.

The core of the question is how to allocate the output byte[] array and how to assign the result of deflating into it. So far, I am using another MemoryStream and its .ToArray() method to assign result, like this:

    byte[] content = row.Field<byte[]>("Content");

    using (var memstream = new MemoryStream(content, 0, content.Length))
    using (var defstream = new DeflateStream(memstream, CompressionMode.Decompress))
    using (var outstream = new MemoryStream())
    {
        defstream.CopyTo(outstream);
        byte[] deflated = outstream.ToArray();

        // ... write the deflated result to the SQL table.
    }

Is that a reasonably efficient solution? Or is there a cleaner way to save the DeflateStream result to byte[]?

I know that the DeflateStream implements the .Read(buffer, 0, bufferSize). However, the size of the result is not known in advance.

Context: The compressed content is a product image in JPEG or PNG. For the reason, the image is compressed once again by Microsoft.

Upvotes: 1

Views: 108

Answers (1)

Charlieface
Charlieface

Reputation: 72197

You can just pass the stream directly as the Value for your command's parameter.

Note: do not dispose the stream with using until the command has been executed.

byte[] content = row.Field<byte[]>("Content");

using (var memstream = new MemoryStream(content))
using (var defstream = new DeflateStream(memstream, CompressionMode.Decompress))
{
    command.Parameters.Add("@yourVarBinary", SqlDbType.VarBinary, -1).Value = defstream;
    command.ExecuteNonQuery.....
}

Assuming row.Field is actually a SqlDataReader, you can do this in both directions.

using (var stream = row.GetStream(row.GetOrdinal("Content")))
using (var defstream = new DeflateStream(stream, CompressionMode.Decompress))
{
    command.Parameters.Add("@yourVarBinary", SqlDbType.VarBinary, -1).Value = defstream;
    command.ExecuteNonQuery.....
}

See also the documentation.

Upvotes: 1

Related Questions