BitMiracle.LibJpeg.Classic.Internal.huff_entropy_decoder.decode_mcu_DC_first C# (CSharp) Method

        private bool decode_mcu_DC_first(JBLOCK[] MCU_data)
        {
            /* Process restart marker if needed; may have to suspend */
            if (m_cinfo.m_restart_interval != 0)
            {
                if (m_restarts_to_go == 0)
                {
                    if (!process_restart())
                        return false;
                }
            }

            /* If we've run out of data, just leave the MCU set to zeroes.
             * This way, we return uniform gray for the remainder of the segment.
             */
            if (!m_insufficient_data)
            {
                /* Load up working state */
                int get_buffer;
                int bits_left;
                bitread_working_state br_state = new bitread_working_state();
                BITREAD_LOAD_STATE(m_bitstate, out get_buffer, out bits_left, ref br_state);
                savable_state state = new savable_state();
                state.Assign(m_saved);

                /* Outer loop handles each block in the MCU */
                for (int blkn = 0; blkn < m_cinfo.m_blocks_in_MCU; blkn++)
                {
                    int ci = m_cinfo.m_MCU_membership[blkn];

                    /* Decode a single block's worth of coefficients */

                    /* Section F.2.2.1: decode the DC coefficient difference */
                    int s;
                    if (!HUFF_DECODE(out s, ref br_state, derived_tbls[m_cinfo.Comp_info[m_cinfo.m_cur_comp_info[ci]].Dc_tbl_no], ref get_buffer, ref bits_left))
                        return false;

                    if (s != 0)
                    {
                        if (!CHECK_BIT_BUFFER(ref br_state, s, ref get_buffer, ref bits_left))
                            return false;

                        int r = GET_BITS(s, get_buffer, ref bits_left);
                        s = HUFF_EXTEND(r, s);
                    }

                    /* Convert DC difference to actual value, update last_dc_val */
                    s += state.last_dc_val[ci];
                    state.last_dc_val[ci] = s;

                    /* Scale and output the coefficient (assumes jpeg_natural_order[0]=0) */
                    MCU_data[blkn][0] = (short)(s << m_cinfo.m_Al);
                }

                /* Completed MCU, so update state */
                BITREAD_SAVE_STATE(ref m_bitstate, get_buffer, bits_left);
                m_saved.Assign(state);
            }

            /* Account for restart interval (no-op if not using restarts) */
            m_restarts_to_go--;

            return true;
        }