tommy.blog

2005-10-14

Reading from and writing to a Stream

Here you can find a class I wrote that allows you to easily read and write byte arrays from and to a Stream. I created it because I needed such functionality on a NetworkStream (where you can't get the length of the stream).

using System;
using System.IO;
namespace TC.Utils {
public class StreamHelper {
   private static byte[] ReadByteArray(Stream stream, int length) {
      byte[] buffer = new byte[length];
      int offset = 0;
      while (offset < length)
         offset += stream.Read(buffer, offset, length - offset);
      return buffer;
   }
   private static void WriteInt32(Stream stream, int value) {
      stream.Write(BitConverter.GetBytes(value), 0, 4);
   }
   private static int ReadInt32(Stream stream) {
      return BitConverter.ToInt32(ReadByteArray(stream, 4), 0);
   }
   public static void WriteByteArray(Stream stream, byte[] data) {
      WriteInt32(stream, data.Length);
      if (data.Length > 0) stream.Write(data, 0, data.Length);
   }
   public static byte[] ReadByteArray(Stream stream) {
      return ReadByteArray(stream, ReadInt32(stream));
   }
}
}

To write:

Stream stream = ...;
byte[] data = ...;
StreamHelper.WriteByteArray(stream, data);

To read:

Stream stream = ...;
byte[] data = StreamHelper.ReadByteArray(stream);

EDIT 15 Oct 2005: Martin Plante of Xceed Software has given me some tips to make the code simpler (using BitConverter instead of manually bit-shifting) and more robust. Thanks!

Tags: C#.

# posted @ 13:34

Comments:

Watch out! Stream.Read may not always return the requested number of bytes. In ReadInt32, you ask of 4 bytes, but it may return 3, 2, or even a single byte. The only thing you can be sure is that it won't return 0 bytes unless it's at the end of the stream (or, in the case of a NetworkStream, it's disconnected).

Either use a BinaryReader around your stream, or loop until you read all bytes.

Also, instead of manually bit-shifting your "length", you can use System.BitConverter. It will simplify your code.

# posted by

Martin Plante : 14 October, 2005 16:19