Question

I’m wondering if there is a better/inbuilt way, other than using a byte buffer and looping, to read from one stream and write it to another (in .NET). Generally this is done to apply a transform to a stream and move it on.

In this instance, what I am loading a file, putting it through a deflate stream and writing it out to a file (Error handling removed for simplicity):

byte[] buffer = new byte[10000000]; using (FileStream fsin = new FileStream(filename, FileMode.Open)) {     using (FileStream fsout = new FileStream(zipfilename, FileMode.CreateNew))     {         using (DeflateStream ds = new DeflateStream(fsout, CompressionMode.Compress))         {             int read = 0;             do             {                 read = fsin.Read(buffer, 0, buffer.Length);                 ds.Write(buffer, 0, read);             }             while (read > 0);         }     } } buffer = null; 

Edit:

.NET 4.0 now has a Stream.CopyTo function, Hallelujah

Answer 1

There’s not really a better way than that, though I tend to put the looping part into a CopyTo extension method, e.g.

public static void CopyTo(this Stream source, Stream destination) {     var buffer = new byte[0x1000];     int bytesInBuffer;     while ((bytesInBuffer = source.Read(buffer, 0, buffer.Length)) > 0)     {         destination.Write(buffer, 0, bytesInBuffer);     } } 

Which you could then call as:

fsin.CopyTo(ds);