BitMiracle.LibJpeg.Classic.Internal.jpeg_marker_reader.get_dac C# (CSharp) Méthode

        private bool get_dac()
        {
            int length;
            if (!m_cinfo.m_src.GetTwoBytes(out length))
                return false;

            length -= 2;
            while (length > 0)
            {
                int index;
                if (!m_cinfo.m_src.GetByte(out index))
                    return false;

                int val;
                if (!m_cinfo.m_src.GetByte(out val))
                    return false;

                length -= 2;

                m_cinfo.TRACEMS(1, J_MESSAGE_CODE.JTRC_DAC, index, val);

                if (index < 0 || index >= (2 * JpegConstants.NUM_ARITH_TBLS))
                    m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_DAC_INDEX, index);

                if (index >= JpegConstants.NUM_ARITH_TBLS)
                { /* define AC table */
                    m_cinfo.arith_ac_K[index - JpegConstants.NUM_ARITH_TBLS] = (byte)val;
                }
                else {          /* define DC table */
                    m_cinfo.arith_dc_L[index] = (byte)(val & 0x0F);
                    m_cinfo.arith_dc_U[index] = (byte)(val >> 4);
                    if (m_cinfo.arith_dc_L[index] > m_cinfo.arith_dc_U[index])
                        m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_DAC_VALUE, val);
                }
            }

            if (length != 0)
                m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_BAD_LENGTH);

            return true;
        }