将剩余的字节从一个字节[]连接到一个新的完整字节[]

Question

I have a TCP stream coming in and it fills up a 256 byte[].

From there I process the byte array parsing out messages etc.

Once I get to < 100 bytes in the first array, I want to take the remaining bytes add them to a new array and then append the new 256 byte array and continue processing so I don't miss messages.

    public static byte[] Combine(byte[] first, byte[] second)
    {
      byte[] ret = new byte[first.Length + second.Length];
      Buffer.BlockCopy(first, 0, ret, 0, first.Length);
      Buffer.BlockCopy(second, 0, ret, first.Length, second.Length);
      return ret;
    }        

I'm using this function (Taken from one of Jon Skeet's post) however there is an issue that happens in that the byte[] continually gets bigger.

For example if I have buffer[] that is 256 and newbuff[] 256 and pass it to the function above...I get back a ret of 512[].

Now if I pass the Combine function again it adds on the 256 to the 512 and continuously grows causing a bit of an issue as I am processing a rather large tcp data feed.

Any suggestions on how to make this more efficient? Currently I have tried using this variation but it seems like I am caught in a circle.

    public static byte[] Combine(byte[] first, byte[] second, int srcOffset)
    {
     byte[] ret = new byte[first.Length -srcOffset + second.Length];
     Buffer.BlockCopy(first, srcOffset, ret, 0, first.Length - srcOffset);
     Buffer.BlockCopy(second, 0, ret, first.Length - srcOffset, second.Length);
     return ret;
   }

Thanks in advance guys!

Answer 1

Maybe this is over simplifying it you can do something like the below, I personally use memory streams withing TCP servers to keep all the data and it's worked out well.

 public static byte[] Combine(byte[] first, byte[] second, int srcOffset)
        {
            MemoryStream result = new MemoryStream();
            result.Write(first, 0, first.Length);
            result.Write(second, 0, srcOffset);
            return result.ToArray();
        }

Answer 2

Your second function seems to do exactly what you want it to do. I tried it out using this small test setup:

byte[] a = new byte[256];
byte[] b = new byte[256];
byte[] c = Combine(a,b, 100);
Console.WriteLine(c.Length);

The result was 412, so exactly what you would expect (512 bytes - 100 processed bytes = 412 bytes). Maybe there is an error in other parts of your code or i misunderstood you. It would be very helpfull if you could provide more context for us. (I dont have enough reputation to comment on your question so I'm posting this as an answer, sorry)