/// <summary>
/// Save away a copy of the Q-table referenced by each component present
/// in the current scan, unless already saved during a prior scan.
///
/// In a multiple-scan JPEG file, the encoder could assign different components
/// the same Q-table slot number, but change table definitions between scans
/// so that each component uses a different Q-table. (The IJG encoder is not
/// currently capable of doing this, but other encoders might.) Since we want
/// to be able to dequantize all the components at the end of the file, this
/// means that we have to save away the table actually used for each component.
/// We do this by copying the table at the start of the first scan containing
/// the component.
/// The JPEG spec prohibits the encoder from changing the contents of a Q-table
/// slot between scans of a component using that slot. If the encoder does so
/// anyway, this decoder will simply use the Q-table values that were current
/// at the start of the first scan for the component.
///
/// The decompressor output side looks only at the saved quant tables,
/// not at the current Q-table slots.
/// </summary>
private void latch_quant_tables()
{
for (int ci = 0; ci < m_cinfo.m_comps_in_scan; ci++)
{
jpeg_component_info componentInfo = m_cinfo.Comp_info[m_cinfo.m_cur_comp_info[ci]];
/* No work if we already saved Q-table for this component */
if (componentInfo.quant_table != null)
{
continue;
}
/* Make sure specified quantization table is present */
int qtblno = componentInfo.Quant_tbl_no;
if (qtblno < 0 || qtblno >= JpegConstants.NUM_QUANT_TBLS || m_cinfo.m_quant_tbl_ptrs[qtblno] == null)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
}
/* OK, save away the quantization table */
JQUANT_TBL qtbl = new JQUANT_TBL();
Buffer.BlockCopy(m_cinfo.m_quant_tbl_ptrs[qtblno].quantval, 0,
qtbl.quantval, 0, qtbl.quantval.Length * sizeof(short));
qtbl.Sent_table = m_cinfo.m_quant_tbl_ptrs[qtblno].Sent_table;
componentInfo.quant_table = qtbl;
m_cinfo.Comp_info[m_cinfo.m_cur_comp_info[ci]] = componentInfo;
}
}
// Save away a copy of the Q-table referenced by each component present
// in the current scan, unless already saved during a prior scan.
//
// In a multiple-scan JPEG file, the encoder could assign different components
// the same Q-table slot number, but change table definitions between scans
// so that each component uses a different Q-table. (The IJG encoder is not
// currently capable of doing this, but other encoders might.) Since we want
// to be able to dequantize all the components at the end of the file, this
// means that we have to save away the table actually used for each component.
// We do this by copying the table at the start of the first scan containing
// the component.
// The JPEG spec prohibits the encoder from changing the contents of a Q-table
// slot between scans of a component using that slot. If the encoder does so
// anyway, this decoder will simply use the Q-table values that were current
// at the start of the first scan for the component.
//
// The decompressor output side looks only at the saved quant tables,
// not at the current Q-table slots.
static void latch_quant_tables_lossy(jpeg_decompress cinfo)
{
for (int ci = 0; ci < cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr = cinfo.cur_comp_info[ci];
// No work if we already saved Q-table for this component
if (compptr.quant_table != null)
{
continue;
}
// Make sure specified quantization table is present
int qtblno = compptr.quant_tbl_no;
if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || cinfo.quant_tbl_ptrs[qtblno] == null)
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
}
// OK, save away the quantization table
JQUANT_TBL qtbl = new JQUANT_TBL();
cinfo.quant_tbl_ptrs[qtblno].quantval.CopyTo(qtbl.quantval, 0);
qtbl.sent_table = cinfo.quant_tbl_ptrs[qtblno].sent_table;
compptr.quant_table = qtbl;
}
}
// Routines to write specific marker types.
// Emit a DQT marker
// Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking
static int emit_dqt(jpeg_compress cinfo, int index)
{
JQUANT_TBL qtbl=cinfo.quant_tbl_ptrs[index];
if(qtbl==null) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, index);
int prec=0;
for(int i=0; i<DCTSIZE2; i++)
{
if(qtbl.quantval[i]>255) prec=1;
}
if(!qtbl.sent_table)
{
emit_marker(cinfo, JPEG_MARKER.M_DQT);
emit_2bytes(cinfo, prec!=0?DCTSIZE2*2+1+2:DCTSIZE2+1+2);
emit_byte(cinfo, index+(prec<<4));
for(int i=0; i<DCTSIZE2; i++)
{
// The table entries must be emitted in zigzag order.
uint qval=qtbl.quantval[jpeg_natural_order[i]];
if(prec!=0) emit_byte(cinfo, (int)(qval>>8));
emit_byte(cinfo, (int)(qval&0xFF));
}
qtbl.sent_table=true;
}
return prec;
}
/// <summary>
/// Determine whether block smoothing is applicable and safe.
/// We also latch the current states of the coef_bits[] entries for the
/// AC coefficients; otherwise, if the input side of the decompressor
/// advances into a new scan, we might think the coefficients are known
/// more accurately than they really are.
/// </summary>
private bool smoothing_ok()
{
if (!m_cinfo.m_progressive_mode || m_cinfo.m_coef_bits == null)
{
return(false);
}
/* Allocate latch area if not already done */
if (m_coef_bits_latch == null)
{
m_coef_bits_latch = new int[m_cinfo.m_num_components * SAVED_COEFS];
m_coef_bits_savedOffset = 0;
}
bool smoothing_useful = false;
for (int ci = 0; ci < m_cinfo.m_num_components; ci++)
{
/* All components' quantization values must already be latched. */
JQUANT_TBL qtable = m_cinfo.Comp_info[ci].quant_table;
if (qtable == null)
{
return(false);
}
/* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
if (qtable.quantval[0] == 0 || qtable.quantval[Q01_POS] == 0 ||
qtable.quantval[Q10_POS] == 0 || qtable.quantval[Q20_POS] == 0 ||
qtable.quantval[Q11_POS] == 0 || qtable.quantval[Q02_POS] == 0)
{
return(false);
}
/* DC values must be at least partly known for all components. */
if (m_cinfo.m_coef_bits[ci][0] < 0)
{
return(false);
}
/* Block smoothing is helpful if some AC coefficients remain inaccurate. */
for (int coefi = 1; coefi <= 5; coefi++)
{
m_coef_bits_latch[m_coef_bits_savedOffset + coefi] = m_cinfo.m_coef_bits[ci][coefi];
if (m_cinfo.m_coef_bits[ci][coefi] != 0)
{
smoothing_useful = true;
}
}
m_coef_bits_savedOffset += SAVED_COEFS;
}
return(smoothing_useful);
}
// Convenience routines for allocating quantization and Huffman tables.
// (Would jutils.cs be a more reasonable place to put these?)
public static JQUANT_TBL jpeg_alloc_quant_table(jpeg_common cinfo)
{
JQUANT_TBL tbl = null;
try
{
tbl = new JQUANT_TBL();
tbl.sent_table = false; // make sure this is false in any new table
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
return(tbl);
}
/// <summary>
/// Emit a DQT marker
/// </summary>
/// <param name="index">The index.</param>
/// <returns>the precision used (0 = 8bits, 1 = 16bits) for baseline checking</returns>
private int emit_dqt(int index)
{
JQUANT_TBL qtbl = m_cinfo.m_quant_tbl_ptrs[index];
if (qtbl == null)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, index);
}
int prec = 0;
for (int i = 0; i <= m_cinfo.lim_Se; i++)
{
if (qtbl.quantval[m_cinfo.natural_order[i]] > 255)
{
prec = 1;
}
}
if (!qtbl.Sent_table)
{
emit_marker(JPEG_MARKER.DQT);
emit_2bytes(prec != 0 ?
m_cinfo.lim_Se * 2 + 2 + 1 + 2 : m_cinfo.lim_Se + 1 + 1 + 2);
emit_byte(index + (prec << 4));
for (int i = 0; i <= m_cinfo.lim_Se; i++)
{
/* The table entries must be emitted in zigzag order. */
int qval = qtbl.quantval[m_cinfo.natural_order[i]];
if (prec != 0)
{
emit_byte(qval >> 8);
}
emit_byte(qval & 0xFF);
}
qtbl.Sent_table = true;
}
return(prec);
}
// Prepare for an output pass.
// Here we select the proper IDCT routine for each component and build
// a matching multiplier table.
static void start_pass_idctmgr(jpeg_decompress cinfo)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
idct_controller idct = (idct_controller)lossyd.idct_private;
for (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
// Select the proper IDCT routine for this component's scaling
lossyd.inverse_DCT[ci] = jpeg_idct_ifast;
// Create multiplier table from quant table.
// However, we can skip this if the component is uninteresting
// or if we already built the table. Also, if no quant table
// has yet been saved for the component, we leave the
// multiplier table all-zero; we'll be reading zeroes from the
// coefficient controller's buffer anyway.
if (!compptr.component_needed || idct.cur_method[ci] == JDCT_IFAST)
{
continue;
}
JQUANT_TBL qtbl = compptr.quant_table;
if (qtbl == null)
{
continue; // happens if no data yet for component
}
idct.cur_method[ci] = JDCT_IFAST;
// For AA&N IDCT method, multipliers are equal to quantization
// coefficients scaled by scalefactor[row]*scalefactor[col], where
// scalefactor[0] = 1
// scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
// For integer operation, the multiplier table is to be scaled by 2.
int[] ifmtbl = compptr.dct_table;
for (int i = 0; i < DCTSIZE2; i++)
{
ifmtbl[i] = (((int)qtbl.quantval[i] * aanscales[i]) + (1 << 11)) >> 12;
}
}
}
// Save away a copy of the Q-table referenced by each component present
// in the current scan, unless already saved during a prior scan.
//
// In a multiple-scan JPEG file, the encoder could assign different components
// the same Q-table slot number, but change table definitions between scans
// so that each component uses a different Q-table. (The IJG encoder is not
// currently capable of doing this, but other encoders might.) Since we want
// to be able to dequantize all the components at the end of the file, this
// means that we have to save away the table actually used for each component.
// We do this by copying the table at the start of the first scan containing
// the component.
// The JPEG spec prohibits the encoder from changing the contents of a Q-table
// slot between scans of a component using that slot. If the encoder does so
// anyway, this decoder will simply use the Q-table values that were current
// at the start of the first scan for the component.
//
// The decompressor output side looks only at the saved quant tables,
// not at the current Q-table slots.
static void latch_quant_tables_lossy(jpeg_decompress cinfo)
{
for(int ci=0; ci<cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr=cinfo.cur_comp_info[ci];
// No work if we already saved Q-table for this component
if(compptr.quant_table!=null) continue;
// Make sure specified quantization table is present
int qtblno=compptr.quant_tbl_no;
if(qtblno<0||qtblno>=NUM_QUANT_TBLS||cinfo.quant_tbl_ptrs[qtblno]==null) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
// OK, save away the quantization table
JQUANT_TBL qtbl=new JQUANT_TBL();
cinfo.quant_tbl_ptrs[qtblno].quantval.CopyTo(qtbl.quantval, 0);
qtbl.sent_table=cinfo.quant_tbl_ptrs[qtblno].sent_table;
compptr.quant_table=qtbl;
}
}
/// <summary>
/// Save away a copy of the Q-table referenced by each component present
/// in the current scan, unless already saved during a prior scan.
///
/// In a multiple-scan JPEG file, the encoder could assign different components
/// the same Q-table slot number, but change table definitions between scans
/// so that each component uses a different Q-table. (The IJG encoder is not
/// currently capable of doing this, but other encoders might.) Since we want
/// to be able to dequantize all the components at the end of the file, this
/// means that we have to save away the table actually used for each component.
/// We do this by copying the table at the start of the first scan containing
/// the component.
/// The JPEG spec prohibits the encoder from changing the contents of a Q-table
/// slot between scans of a component using that slot. If the encoder does so
/// anyway, this decoder will simply use the Q-table values that were current
/// at the start of the first scan for the component.
///
/// The decompressor output side looks only at the saved quant tables,
/// not at the current Q-table slots.
/// </summary>
private void latch_quant_tables()
{
for (int ci = 0; ci < m_cinfo.m_comps_in_scan; ci++)
{
jpeg_component_info componentInfo = m_cinfo.Comp_info[m_cinfo.m_cur_comp_info[ci]];
/* No work if we already saved Q-table for this component */
if (componentInfo.quant_table != null)
continue;
/* Make sure specified quantization table is present */
int qtblno = componentInfo.Quant_tbl_no;
if (qtblno < 0 || qtblno >= JpegConstants.NUM_QUANT_TBLS || m_cinfo.m_quant_tbl_ptrs[qtblno] == null)
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
/* OK, save away the quantization table */
JQUANT_TBL qtbl = new JQUANT_TBL();
Buffer.BlockCopy(m_cinfo.m_quant_tbl_ptrs[qtblno].quantval, 0,
qtbl.quantval, 0, qtbl.quantval.Length * sizeof(short));
qtbl.Sent_table = m_cinfo.m_quant_tbl_ptrs[qtblno].Sent_table;
componentInfo.quant_table = qtbl;
m_cinfo.Comp_info[m_cinfo.m_cur_comp_info[ci]] = componentInfo;
}
}
/// <summary>
/// Process a DQT marker
/// </summary>
private bool get_dqt()
{
int length;
if (!m_cinfo.m_src.GetTwoBytes(out length))
{
return(false);
}
length -= 2;
while (length > 0)
{
int n;
if (!m_cinfo.m_src.GetByte(out n))
{
return(false);
}
int prec = n >> 4;
n &= 0x0F;
m_cinfo.TRACEMS(1, J_MESSAGE_CODE.JTRC_DQT, n, prec);
if (n >= JpegConstants.NUM_QUANT_TBLS)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_DQT_INDEX, n);
}
if (m_cinfo.m_quant_tbl_ptrs[n] == null)
{
m_cinfo.m_quant_tbl_ptrs[n] = new JQUANT_TBL();
}
JQUANT_TBL quant_ptr = m_cinfo.m_quant_tbl_ptrs[n];
for (int i = 0; i < JpegConstants.DCTSIZE2; i++)
{
int tmp;
if (prec != 0)
{
int temp = 0;
if (!m_cinfo.m_src.GetTwoBytes(out temp))
{
return(false);
}
tmp = temp;
}
else
{
int temp = 0;
if (!m_cinfo.m_src.GetByte(out temp))
{
return(false);
}
tmp = temp;
}
/* We convert the zigzag-order table to natural array order. */
quant_ptr.quantval[JpegUtils.jpeg_natural_order[i]] = (short)tmp;
}
if (m_cinfo.m_err.m_trace_level >= 2)
{
for (int i = 0; i < JpegConstants.DCTSIZE2; i += 8)
{
m_cinfo.TRACEMS(2, J_MESSAGE_CODE.JTRC_QUANTVALS, quant_ptr.quantval[i],
quant_ptr.quantval[i + 1], quant_ptr.quantval[i + 2],
quant_ptr.quantval[i + 3], quant_ptr.quantval[i + 4],
quant_ptr.quantval[i + 5], quant_ptr.quantval[i + 6], quant_ptr.quantval[i + 7]);
}
}
length -= JpegConstants.DCTSIZE2 + 1;
if (prec != 0)
{
length -= JpegConstants.DCTSIZE2;
}
}
if (length != 0)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_BAD_LENGTH);
}
return(true);
}
/// <summary>
/// Initialize for a processing pass.
/// Verify that all referenced Q-tables are present, and set up
/// the divisor table for each one.
/// In the current implementation, DCT of all components is done during
/// the first pass, even if only some components will be output in the
/// first scan. Hence all components should be examined here.
/// </summary>
public virtual void start_pass()
{
for (int ci = 0; ci < m_cinfo.m_num_components; ci++)
{
int qtblno = m_cinfo.Component_info[ci].Quant_tbl_no;
/* Make sure specified quantization table is present */
if (qtblno < 0 || qtblno >= JpegConstants.NUM_QUANT_TBLS || m_cinfo.m_quant_tbl_ptrs[qtblno] == null)
{
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
}
JQUANT_TBL qtbl = m_cinfo.m_quant_tbl_ptrs[qtblno];
/* Compute divisors for this quant table */
/* We may do this more than once for same table, but it's not a big deal */
int i = 0;
switch (m_cinfo.m_dct_method)
{
case J_DCT_METHOD.JDCT_ISLOW:
/* For LL&M IDCT method, divisors are equal to raw quantization
* coefficients multiplied by 8 (to counteract scaling).
*/
if (m_divisors[qtblno] == null)
{
m_divisors[qtblno] = new int [JpegConstants.DCTSIZE2];
}
for (i = 0; i < JpegConstants.DCTSIZE2; i++)
{
m_divisors[qtblno][i] = ((int)qtbl.quantval[i]) << 3;
}
break;
case J_DCT_METHOD.JDCT_IFAST:
if (m_divisors[qtblno] == null)
{
m_divisors[qtblno] = new int [JpegConstants.DCTSIZE2];
}
for (i = 0; i < JpegConstants.DCTSIZE2; i++)
{
m_divisors[qtblno][i] = JpegUtils.DESCALE((int)qtbl.quantval[i] * (int)aanscales[i], CONST_BITS - 3);
}
break;
case J_DCT_METHOD.JDCT_FLOAT:
if (m_float_divisors[qtblno] == null)
{
m_float_divisors[qtblno] = new float [JpegConstants.DCTSIZE2];
}
float[] fdtbl = m_float_divisors[qtblno];
i = 0;
for (int row = 0; row < JpegConstants.DCTSIZE; row++)
{
for (int col = 0; col < JpegConstants.DCTSIZE; col++)
{
fdtbl[i] = (float)(1.0 / (((double)qtbl.quantval[i] * aanscalefactor[row] * aanscalefactor[col] * 8.0)));
i++;
}
}
break;
default:
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_NOT_COMPILED);
break;
}
}
}
// Variant of decompress_data for use when doing block smoothing.
static CONSUME_INPUT decompress_smooth_data(jpeg_decompress cinfo, byte[][][] output_buf)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
d_coef_controller coef = (d_coef_controller)lossyd.coef_private;
// Force some input to be done if we are getting ahead of the input.
while (cinfo.input_scan_number <= cinfo.output_scan_number && !cinfo.inputctl.eoi_reached)
{
if (cinfo.input_scan_number == cinfo.output_scan_number)
{
// If input is working on current scan, we ordinarily want it to
// have completed the current row. But if input scan is DC,
// we want it to keep one row ahead so that next block row's DC
// values are up to date.
uint delta = (cinfo.Ss == 0)?1u:0u;
if (cinfo.input_iMCU_row > cinfo.output_iMCU_row + delta)
{
break;
}
}
if (cinfo.inputctl.consume_input(cinfo) == CONSUME_INPUT.JPEG_SUSPENDED)
{
return(CONSUME_INPUT.JPEG_SUSPENDED);
}
}
uint last_iMCU_row = cinfo.total_iMCU_rows - 1;
short[] workspace = new short[DCTSIZE2];
// OK, output from the arrays.
for (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
// Don't bother to IDCT an uninteresting component.
if (!compptr.component_needed)
{
continue;
}
// Count non-dummy DCT block rows in this iMCU row.
int block_rows, access_rows;
bool last_row;
if (cinfo.output_iMCU_row < last_iMCU_row)
{
block_rows = compptr.v_samp_factor;
access_rows = block_rows * 2; // this and next iMCU row
last_row = false;
}
else
{
// NB: can't use last_row_height here; it is input-side-dependent!
block_rows = (int)(compptr.height_in_blocks % compptr.v_samp_factor);
if (block_rows == 0)
{
block_rows = compptr.v_samp_factor;
}
access_rows = block_rows; // this iMCU row only
last_row = true;
}
// Align the buffer for this component.
bool first_row;
short[][][] buffer;
int buffer_ind;
if (cinfo.output_iMCU_row > 0)
{
access_rows += compptr.v_samp_factor; // prior iMCU row too
buffer = coef.whole_image[ci];
buffer_ind = (int)cinfo.output_iMCU_row * compptr.v_samp_factor; // point to current iMCU row
first_row = false;
}
else
{
buffer = coef.whole_image[ci];
buffer_ind = 0;
first_row = true;
}
// Fetch component-dependent info
int[] coef_bits = coef.coef_bits_latch[ci];
JQUANT_TBL quanttbl = compptr.quant_table;
int Q00 = quanttbl.quantval[0];
int Q01 = quanttbl.quantval[Q01_POS];
int Q10 = quanttbl.quantval[Q10_POS];
int Q20 = quanttbl.quantval[Q20_POS];
int Q11 = quanttbl.quantval[Q11_POS];
int Q02 = quanttbl.quantval[Q02_POS];
inverse_DCT_method_ptr inverse_DCT = lossyd.inverse_DCT[ci];
uint output_buf_ind = 0;
// Loop over all DCT blocks to be processed.
for (int block_row = 0; block_row < block_rows; block_row++)
{
short[][] buffer_ptr = buffer[buffer_ind + block_row];
short[][] prev_block_row;
short[][] next_block_row;
if (first_row && block_row == 0)
{
prev_block_row = buffer_ptr;
}
else
{
prev_block_row = buffer[buffer_ind + block_row - 1];
}
if (last_row && block_row == block_rows - 1)
{
next_block_row = buffer_ptr;
}
else
{
next_block_row = buffer[buffer_ind + block_row + 1];
}
// We fetch the surrounding DC values using a sliding-register approach.
// Initialize all nine here so as to do the right thing on narrow pics.
int DC1, DC2, DC3, DC4, DC5, DC6, DC7, DC8, DC9;
DC1 = DC2 = DC3 = (int)prev_block_row[0][0];
DC4 = DC5 = DC6 = (int)buffer_ptr[0][0];
DC7 = DC8 = DC9 = (int)next_block_row[0][0];
int ind = 1;
uint output_col = 0;
uint last_block_column = compptr.width_in_blocks - 1;
for (uint block_num = 0; block_num <= last_block_column; block_num++)
{
// Fetch current DCT block into workspace so we can modify it.
buffer_ptr.CopyTo(workspace, 0);
// Update DC values
if (block_num < last_block_column)
{
DC3 = (int)prev_block_row[ind][0];
DC6 = (int)buffer_ptr[ind][0];
DC9 = (int)next_block_row[ind][0];
}
// Compute coefficient estimates per K.8.
// An estimate is applied only if coefficient is still zero,
// and is not known to be fully accurate.
// AC01
int Al = coef_bits[1];
if (Al != 0 && workspace[1] == 0)
{
int num = 36 * Q00 * (DC4 - DC6);
int pred;
if (num >= 0)
{
pred = (int)(((Q01 << 7) + num) / (Q01 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
}
else
{
pred = (int)(((Q01 << 7) - num) / (Q01 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
pred = -pred;
}
workspace[1] = (short)pred;
}
// AC10
Al = coef_bits[2];
if (Al != 0 && workspace[8] == 0)
{
int num = 36 * Q00 * (DC2 - DC8);
int pred;
if (num >= 0)
{
pred = (int)(((Q10 << 7) + num) / (Q10 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
}
else
{
pred = (int)(((Q10 << 7) - num) / (Q10 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
pred = -pred;
}
workspace[8] = (short)pred;
}
// AC20
Al = coef_bits[3];
if (Al != 0 && workspace[16] == 0)
{
int num = 9 * Q00 * (DC2 + DC8 - 2 * DC5);
int pred;
if (num >= 0)
{
pred = (int)(((Q20 << 7) + num) / (Q20 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
}
else
{
pred = (int)(((Q20 << 7) - num) / (Q20 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
pred = -pred;
}
workspace[16] = (short)pred;
}
// AC11
Al = coef_bits[4];
if (Al != 0 && workspace[9] == 0)
{
int num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
int pred;
if (num >= 0)
{
pred = (int)(((Q11 << 7) + num) / (Q11 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
}
else
{
pred = (int)(((Q11 << 7) - num) / (Q11 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
pred = -pred;
}
workspace[9] = (short)pred;
}
// AC02
Al = coef_bits[5];
if (Al != 0 && workspace[2] == 0)
{
int num = 9 * Q00 * (DC4 + DC6 - 2 * DC5);
int pred;
if (num >= 0)
{
pred = (int)(((Q02 << 7) + num) / (Q02 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
}
else
{
pred = (int)(((Q02 << 7) - num) / (Q02 << 8));
if (Al > 0 && pred >= (1 << Al))
{
pred = (1 << Al) - 1;
}
pred = -pred;
}
workspace[2] = (short)pred;
}
// OK, do the IDCT
inverse_DCT(cinfo, compptr, workspace, output_buf[ci], output_buf_ind, output_col);
// Advance for next column
DC1 = DC2; DC2 = DC3;
DC4 = DC5; DC5 = DC6;
DC7 = DC8; DC8 = DC9;
ind++;
output_col += compptr.DCT_scaled_size;
}
output_buf_ind += compptr.DCT_scaled_size;
}
}
if (++(cinfo.output_iMCU_row) < cinfo.total_iMCU_rows)
{
return(CONSUME_INPUT.JPEG_ROW_COMPLETED);
}
return(CONSUME_INPUT.JPEG_SCAN_COMPLETED);
}
// Determine whether block smoothing is applicable and safe.
// We also latch the current states of the coef_bits[] entries for the
// AC coefficients; otherwise, if the input side of the decompressor
// advances into a new scan, we might think the coefficients are known
// more accurately than they really are.
static bool smoothing_ok(jpeg_decompress cinfo)
{
jpeg_lossy_d_codec lossyd = (jpeg_lossy_d_codec)cinfo.coef;
d_coef_controller coef = (d_coef_controller)lossyd.coef_private;
if (cinfo.process != J_CODEC_PROCESS.JPROC_PROGRESSIVE || cinfo.coef_bits == null)
{
return(false);
}
// Allocate latch area if not already done
if (coef.coef_bits_latch == null)
{
try
{
coef.coef_bits_latch = new int[cinfo.num_components][];
for (int i = 0; i < cinfo.num_components; i++)
{
coef.coef_bits_latch[i] = new int[SAVED_COEFS];
}
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
bool smoothing_useful = false;
for (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
// All components' quantization values must already be latched.
JQUANT_TBL qtable = compptr.quant_table;
if (qtable == null)
{
return(false);
}
// Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide.
if (qtable.quantval[0] == 0 || qtable.quantval[Q01_POS] == 0 || qtable.quantval[Q10_POS] == 0 || qtable.quantval[Q20_POS] == 0 || qtable.quantval[Q11_POS] == 0 || qtable.quantval[Q02_POS] == 0)
{
return(false);
}
// DC values must be at least partly known for all components.
int[] coef_bits = cinfo.coef_bits[ci];
if (coef_bits[0] < 0)
{
return(false);
}
// Block smoothing is helpful if some AC coefficients remain inaccurate.
for (int coefi = 1; coefi <= 5; coefi++)
{
coef.coef_bits_latch[ci][coefi] = coef_bits[coefi];
if (coef_bits[coefi] != 0)
{
smoothing_useful = true;
}
}
}
return(smoothing_useful);
}
// Initialize for a processing pass.
// Verify that all referenced Q-tables are present, and set up
// the divisor table for each one.
// In the current implementation, DCT of all components is done during
// the first pass, even if only some components will be output in the
// first scan. Hence all components should be examined here.
static void start_pass_fdctmgr(jpeg_compress cinfo)
{
jpeg_lossy_c_codec lossyc = (jpeg_lossy_c_codec)cinfo.coef;
fdct_controller fdct = (fdct_controller)lossyc.fdct_private;
for (int ci = 0; ci < cinfo.num_components; ci++)
{
jpeg_component_info compptr = cinfo.comp_info[ci];
int qtblno = compptr.quant_tbl_no;
// Make sure specified quantization table is present
if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || cinfo.quant_tbl_ptrs[qtblno] == null)
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_QUANT_TABLE, qtblno);
}
JQUANT_TBL qtbl = cinfo.quant_tbl_ptrs[qtblno];
// Compute divisors for this quant table
// We may do this more than once for same table, but it's not a big deal
if (fdct.divisors[qtblno] == null)
{
try
{
fdct.divisors[qtblno] = new int[DCTSIZE2];
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
int[] dtbl = fdct.divisors[qtblno];
for (int i = 0; i < DCTSIZE2; i++)
{
dtbl[i] = ((int)qtbl.quantval[i] * aanscales[i] + 1024) >> 11;
}
#if DCT_FLOAT_SUPPORTED
if (fdct.float_divisors[qtblno] == null)
{
try
{
fdct.float_divisors[qtblno] = new double[DCTSIZE2];
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
double[] fdtbl = fdct.float_divisors[qtblno];
int di = 0;
for (int row = 0; row < DCTSIZE; row++)
{
for (int col = 0; col < DCTSIZE; col++)
{
fdtbl[di] = 1.0 / (qtbl.quantval[di] * aanscalefactor[row] * aanscalefactor[col] * 8.0);
di++;
}
}
#endif
}
}
