ApplyMask() [2/2]

static unsafe int System.Net.WebSockets.ManagedWebSocket.ApplyMask ( Span< byte > toMask, int mask, int maskIndex )

inlinestaticprivate

Definition at line 1412 of file ManagedWebSocket.cs.

    {
        fixed (byte* ptr = &MemoryMarshal.GetReference(toMask))
        {
            byte* ptr2 = ptr;
            byte* ptr3 = ptr + toMask.Length;
            byte* ptr4 = (byte*)(&mask);
            if (ptr3 - ptr2 >= 4)
            {
                while ((ulong)ptr2 % 4uL != 0L)
                {
                    byte* intPtr = ptr2++;
                    *intPtr ^= ptr4[maskIndex];
                    maskIndex = (maskIndex + 1) & 3;
                }
                int num = (int)((!BitConverter.IsLittleEndian) ? BitOperations.RotateLeft((uint)mask, maskIndex * 8) : BitOperations.RotateRight((uint)mask, maskIndex * 8));
                if (Vector.IsHardwareAccelerated && Vector<byte>.Count % 4 == 0 && ptr3 - ptr2 >= Vector<byte>.Count)
                {
                    for (; (ulong)ptr2 % (ulong)(uint)Vector<byte>.Count != 0L; ptr2 += 4)
                    {
                        *(int*)ptr2 ^= num;
                    }
                    if (ptr3 - ptr2 >= Vector<byte>.Count)
                    {
                        Vector<byte> vector = Vector.AsVectorByte(new Vector<int>(num));
                        do
                        {
                            *(Vector<byte>*)ptr2 ^= vector;
                            ptr2 += Vector<byte>.Count;
                        }
                        while (ptr3 - ptr2 >= Vector<byte>.Count);
                    }
                }
                for (; ptr3 - ptr2 >= 4; ptr2 += 4)
                {
                    *(int*)ptr2 ^= num;
                }
            }
            while (ptr2 != ptr3)
            {
                byte* intPtr2 = ptr2++;
                *intPtr2 ^= ptr4[maskIndex];
                maskIndex = (maskIndex + 1) & 3;
            }
        }
        return maskIndex;
    }

References System.Numerics.Vector< T >.Count, System.Numerics.Vector< T >.IsHardwareAccelerated, System.BitConverter.IsLittleEndian, System.L, System.Span< T >.Length, System.Numerics.BitOperations.RotateLeft(), and System.Numerics.BitOperations.RotateRight().