BitMiracle.LibJpeg.BitStream.read C# (CSharp) Method

        private int read(int bitsCount)
        {
            //Codes are packed into a continuous bit stream, high-order bit first. 
            //This stream is then divided into 8-bit bytes, high-order bit first. 
            //Thus, codes can straddle byte boundaries arbitrarily. After the EOD marker (code value 257), 
            //any leftover bits in the final byte are set to 0.

            if (bitsCount < 0 || bitsCount > 32)
                throw new ArgumentOutOfRangeException("bitsCount");

            if (bitsCount == 0)
                return 0;

            int bitsRead = 0;
            int result = 0;
            byte[] bt = new byte[1];
            while (bitsRead == 0 || (bitsRead - m_positionInByte < bitsCount))
            {
                m_stream.Read(bt, 0, 1);

                result = (result << bitsInByte);
                result += bt[0];

                bitsRead += 8;
            }

            m_positionInByte = (m_positionInByte + bitsCount) % 8;
            if (m_positionInByte != 0)
            {
                result = (result >> (bitsInByte - m_positionInByte));

                m_stream.Seek(-1, SeekOrigin.Current);
            }

            if (bitsCount < 32)
            {
                int mask = ((1 << bitsCount) - 1);
                result = result & mask;
            }

            return result;
        }