ServiceStack.Text.RecyclableMemoryStream.InternalRead C# (CSharp) Method

        private int InternalRead(byte[] buffer, int offset, int count, int fromPosition)
        {
            if (this.length - fromPosition <= 0)
            {
                return 0;
            }
            if (this.largeBuffer == null)
            {
                var blockAndOffset = this.GetBlockAndRelativeOffset(fromPosition);
                int bytesWritten = 0;
                int bytesRemaining = Math.Min(count, this.length - fromPosition);

                while (bytesRemaining > 0)
                {
                    int amountToCopy = Math.Min(this.blocks[blockAndOffset.Block].Length - blockAndOffset.Offset, bytesRemaining);
                    Buffer.BlockCopy(this.blocks[blockAndOffset.Block], blockAndOffset.Offset, buffer, bytesWritten + offset, amountToCopy);

                    bytesWritten += amountToCopy;
                    bytesRemaining -= amountToCopy;

                    ++blockAndOffset.Block;
                    blockAndOffset.Offset = 0;
                }
                return bytesWritten;
            }
            else
            {
                int amountToCopy = Math.Min(count, this.length - fromPosition);
                Buffer.BlockCopy(this.largeBuffer, fromPosition, buffer, offset, amountToCopy);
                return amountToCopy;
            }
        }