C# simple uudecode implementation

uudecode.cs

public static Byte[] UUDecode(StreamReader input)
{
    var result = new MemoryStream();

    for(String ascii; (ascii = input.ReadLine()) != null;)
    {
        var encodedBuffer = Encoding.ASCII.GetBytes(ascii);

        if(encodedBuffer[0] == 0x60) break;

        var nrDecoded = encodedBuffer[0] - 32;
        var decoded = new Byte[nrDecoded];

        for(Int32 i = 1, j = 0; ; i += 4)
        {
            var tmp = encodedBuffer.Skip(i).Take(4).Select(b => (Byte)((b - 0x20) & 0x3F)).ToArray();

            decoded[j++] = (Byte)(tmp[0] << 2 | tmp[1] >> 4);
            if(j == nrDecoded) break;

            decoded[j++] = (Byte)(tmp[1] << 4 | tmp[2] >> 2);
            if(j == nrDecoded) break;

            decoded[j++] = (Byte)(tmp[2] << 6 | tmp[3]);
            if(j == nrDecoded) break;
        }

        result.Write(decoded, 0, nrDecoded);
    }

    return result.ToArray();
}