Efficient way to read big endian data in C#

Question

I use the following code to read BigEndian information using BinaryReader but I'm not sure if it is the efficient way of doing it. Is there any better solution?

Here is my code:

// some code to initialize the stream value
// set the length value to the Int32 size
BinaryReader reader =new BinaryReader(stream);
byte[] bytes = reader.ReadBytes(length);
Array.Reverse(bytes);
int result = System.BitConverter.ToInt32(temp, 0);

Answer 1

BitConverter.ToInt32 isn't very fast in the first place. I'd simply use

public static int ToInt32BigEndian(byte[] buf, int i)
{
  return (buf[i]<<24) | (buf[i+1]<<16) | (buf[i+2]<<8) | buf[i+3];
}

You could also consider reading more than 4 bytes at a time.

Answer 2

As of 2019 (in fact, since .net core 2.1), there is now

byte[] buffer = ...;

BinaryPrimitives.ReadInt32BigEndian(buffer.AsSpan());

Documentation

Implementation

Answer 3

You could use IPAddress.NetworkToHostOrder, but I have no idea if it's actually more efficient. You'd have to profile it.