Revision control
++ /*
++ * jdcoefct.c
++ *
++ * This file was part of the Independent JPEG Group's software:
++ * Copyright (C) 1994-1997, Thomas G. Lane.
++ * libjpeg-turbo Modifications:
++ * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
++ * Copyright (C) 2010, 2015-2016, 2019-2020, 2022-2026, D. R. Commander.
++ * Copyright (C) 2015, 2020, Google, Inc.
++ * For conditions of distribution and use, see the accompanying README.ijg
++ * file.
++ *
++ * This file contains the coefficient buffer controller for decompression.
++ * This controller is the top level of the lossy JPEG decompressor proper.
++ * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
++ *
++ * In buffered-image mode, this controller is the interface between
++ * input-oriented processing and output-oriented processing.
++ * Also, the input side (only) is used when reading a file for transcoding.
++ */
++
++ #include "jinclude.h"
++ #include "jdcoefct.h"
++ #include "jpegapicomp.h"
++ #include "jsamplecomp.h"
++ #ifdef WITH_PROFILE
++ #include "tjutil.h"
++ #endif
++
++
++ /* Forward declarations */
++ METHODDEF(int) decompress_onepass(j_decompress_ptr cinfo,
++ _JSAMPIMAGE output_buf);
++ #ifdef D_MULTISCAN_FILES_SUPPORTED
++ METHODDEF(int) decompress_data(j_decompress_ptr cinfo, _JSAMPIMAGE output_buf);
++ #endif
++ #ifdef BLOCK_SMOOTHING_SUPPORTED
++ LOCAL(boolean) smoothing_ok(j_decompress_ptr cinfo);
++ METHODDEF(int) decompress_smooth_data(j_decompress_ptr cinfo,
++ _JSAMPIMAGE output_buf);
++ #endif
++
++
++ /*
++ * Initialize for an input processing pass.
++ */
++
++ METHODDEF(void)
++ start_input_pass(j_decompress_ptr cinfo)
++ {
++ cinfo->input_iMCU_row = 0;
++ start_iMCU_row(cinfo);
++ }
++
++
++ /*
++ * Initialize for an output processing pass.
++ */
++
++ METHODDEF(void)
++ start_output_pass(j_decompress_ptr cinfo)
++ {
++ #ifdef BLOCK_SMOOTHING_SUPPORTED
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++
++ /* If multipass, check to see whether to use block smoothing on this pass */
++ if (coef->pub.coef_arrays != NULL) {
++ if (cinfo->do_block_smoothing && smoothing_ok(cinfo))
++ coef->pub._decompress_data = decompress_smooth_data;
++ else
++ coef->pub._decompress_data = decompress_data;
++ }
++ #endif
++ cinfo->output_iMCU_row = 0;
++ }
++
++
++ /*
++ * Decompress and return some data in the single-pass case.
++ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
++ * Input and output must run in lockstep since we have only a one-MCU buffer.
++ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
++ *
++ * NB: output_buf contains a plane for each component in image,
++ * which we index according to the component's SOF position.
++ */
++
++ METHODDEF(int)
++ decompress_onepass(j_decompress_ptr cinfo, _JSAMPIMAGE output_buf)
++ {
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++ JDIMENSION MCU_col_num; /* index of current MCU within row */
++ JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
++ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
++ int blkn, ci, xindex, yindex, yoffset, useful_width;
++ _JSAMPARRAY output_ptr;
++ JDIMENSION start_col, output_col;
++ jpeg_component_info *compptr;
++ _inverse_DCT_method_ptr inverse_DCT;
++
++ /* Loop to process as much as one whole iMCU row */
++ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
++ yoffset++) {
++ for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col;
++ MCU_col_num++) {
++ /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */
++ jzero_far((void *)coef->MCU_buffer[0],
++ (size_t)(cinfo->blocks_in_MCU * sizeof(JBLOCK)));
++ if (!cinfo->entropy->insufficient_data)
++ cinfo->master->last_good_iMCU_row = cinfo->input_iMCU_row;
++ #ifdef WITH_PROFILE
++ cinfo->master->start = getTime();
++ #endif
++ if (!(*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
++ /* Suspension forced; update state counters and exit */
++ coef->MCU_vert_offset = yoffset;
++ coef->MCU_ctr = MCU_col_num;
++ #ifdef WITH_PROFILE
++ cinfo->master->entropy_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->entropy_mcoeffs +=
++ (double)cinfo->blocks_in_MCU * DCTSIZE2 / 1000000.;
++ #endif
++ return JPEG_SUSPENDED;
++ }
++ #ifdef WITH_PROFILE
++ cinfo->master->entropy_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->entropy_mcoeffs +=
++ (double)cinfo->blocks_in_MCU * DCTSIZE2 / 1000000.;
++ #endif
++
++ /* Only perform the IDCT on blocks that are contained within the desired
++ * cropping region.
++ */
++ if (MCU_col_num >= cinfo->master->first_iMCU_col &&
++ MCU_col_num <= cinfo->master->last_iMCU_col) {
++ /* Determine where data should go in output_buf and do the IDCT thing.
++ * We skip dummy blocks at the right and bottom edges (but blkn gets
++ * incremented past them!). Note the inner loop relies on having
++ * allocated the MCU_buffer[] blocks sequentially.
++ */
++ blkn = 0; /* index of current DCT block within MCU */
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ compptr = cinfo->cur_comp_info[ci];
++ /* Don't bother to IDCT an uninteresting component. */
++ if (!compptr->component_needed) {
++ blkn += compptr->MCU_blocks;
++ continue;
++ }
++ inverse_DCT = cinfo->idct->_inverse_DCT[compptr->component_index];
++ useful_width = (MCU_col_num < last_MCU_col) ?
++ compptr->MCU_width : compptr->last_col_width;
++ output_ptr = output_buf[compptr->component_index] +
++ yoffset * compptr->_DCT_scaled_size;
++ start_col = (MCU_col_num - cinfo->master->first_iMCU_col) *
++ compptr->MCU_sample_width;
++ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
++ if (cinfo->input_iMCU_row < last_iMCU_row ||
++ yoffset + yindex < compptr->last_row_height) {
++ output_col = start_col;
++ for (xindex = 0; xindex < useful_width; xindex++) {
++ #ifdef WITH_PROFILE
++ cinfo->master->start = getTime();
++ #endif
++ (*inverse_DCT) (cinfo, compptr,
++ (JCOEFPTR)coef->MCU_buffer[blkn + xindex],
++ output_ptr, output_col);
++ #ifdef WITH_PROFILE
++ cinfo->master->idct_elapsed +=
++ getTime() - cinfo->master->start;
++ cinfo->master->idct_mcoeffs += (double)DCTSIZE2 / 1000000.;
++ #endif
++ output_col += compptr->_DCT_scaled_size;
++ }
++ }
++ blkn += compptr->MCU_width;
++ output_ptr += compptr->_DCT_scaled_size;
++ }
++ }
++ }
++ }
++ /* Completed an MCU row, but perhaps not an iMCU row */
++ coef->MCU_ctr = 0;
++ }
++ /* Completed the iMCU row, advance counters for next one */
++ cinfo->output_iMCU_row++;
++ if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
++ start_iMCU_row(cinfo);
++ return JPEG_ROW_COMPLETED;
++ }
++ /* Completed the scan */
++ (*cinfo->inputctl->finish_input_pass) (cinfo);
++ return JPEG_SCAN_COMPLETED;
++ }
++
++
++ /*
++ * Dummy consume-input routine for single-pass operation.
++ */
++
++ METHODDEF(int)
++ dummy_consume_data(j_decompress_ptr cinfo)
++ {
++ return JPEG_SUSPENDED; /* Always indicate nothing was done */
++ }
++
++
++ #ifdef D_MULTISCAN_FILES_SUPPORTED
++
++ /*
++ * Consume input data and store it in the full-image coefficient buffer.
++ * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
++ * ie, v_samp_factor block rows for each component in the scan.
++ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
++ */
++
++ METHODDEF(int)
++ consume_data(j_decompress_ptr cinfo)
++ {
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++ JDIMENSION MCU_col_num; /* index of current MCU within row */
++ int blkn, ci, xindex, yindex, yoffset;
++ JDIMENSION start_col;
++ JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
++ JBLOCKROW buffer_ptr;
++ jpeg_component_info *compptr;
++
++ /* Align the virtual buffers for the components used in this scan. */
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ compptr = cinfo->cur_comp_info[ci];
++ buffer[ci] = (*cinfo->mem->access_virt_barray)
++ ((j_common_ptr)cinfo, coef->whole_image[compptr->component_index],
++ cinfo->input_iMCU_row * compptr->v_samp_factor,
++ (JDIMENSION)compptr->v_samp_factor, TRUE);
++ /* Note: entropy decoder expects buffer to be zeroed,
++ * but this is handled automatically by the memory manager
++ * because we requested a pre-zeroed array.
++ */
++ }
++
++ /* Loop to process one whole iMCU row */
++ for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
++ yoffset++) {
++ for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row;
++ MCU_col_num++) {
++ /* Construct list of pointers to DCT blocks belonging to this MCU */
++ blkn = 0; /* index of current DCT block within MCU */
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ compptr = cinfo->cur_comp_info[ci];
++ start_col = MCU_col_num * compptr->MCU_width;
++ for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
++ buffer_ptr = buffer[ci][yindex + yoffset] + start_col;
++ for (xindex = 0; xindex < compptr->MCU_width; xindex++) {
++ coef->MCU_buffer[blkn++] = buffer_ptr++;
++ }
++ }
++ }
++ if (!cinfo->entropy->insufficient_data)
++ cinfo->master->last_good_iMCU_row = cinfo->input_iMCU_row;
++ /* Try to fetch the MCU. */
++ #ifdef WITH_PROFILE
++ cinfo->master->start = getTime();
++ #endif
++ if (!(*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) {
++ /* Suspension forced; update state counters and exit */
++ coef->MCU_vert_offset = yoffset;
++ coef->MCU_ctr = MCU_col_num;
++ #ifdef WITH_PROFILE
++ cinfo->master->entropy_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->entropy_mcoeffs +=
++ (double)cinfo->blocks_in_MCU * DCTSIZE2 / 1000000.;
++ #endif
++ return JPEG_SUSPENDED;
++ }
++ #ifdef WITH_PROFILE
++ cinfo->master->entropy_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->entropy_mcoeffs +=
++ (double)cinfo->blocks_in_MCU * DCTSIZE2 / 1000000.;
++ #endif
++ }
++ /* Completed an MCU row, but perhaps not an iMCU row */
++ coef->MCU_ctr = 0;
++ }
++ /* Completed the iMCU row, advance counters for next one */
++ if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) {
++ start_iMCU_row(cinfo);
++ return JPEG_ROW_COMPLETED;
++ }
++ /* Completed the scan */
++ (*cinfo->inputctl->finish_input_pass) (cinfo);
++ return JPEG_SCAN_COMPLETED;
++ }
++
++
++ /*
++ * Decompress and return some data in the multi-pass case.
++ * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
++ * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
++ *
++ * NB: output_buf contains a plane for each component in image.
++ */
++
++ METHODDEF(int)
++ decompress_data(j_decompress_ptr cinfo, _JSAMPIMAGE output_buf)
++ {
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
++ JDIMENSION block_num;
++ int ci, block_row, block_rows;
++ JBLOCKARRAY buffer;
++ JBLOCKROW buffer_ptr;
++ _JSAMPARRAY output_ptr;
++ JDIMENSION output_col;
++ jpeg_component_info *compptr;
++ _inverse_DCT_method_ptr inverse_DCT;
++
++ /* Force some input to be done if we are getting ahead of the input. */
++ while (cinfo->input_scan_number < cinfo->output_scan_number ||
++ (cinfo->input_scan_number == cinfo->output_scan_number &&
++ cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) {
++ if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
++ return JPEG_SUSPENDED;
++ }
++
++ /* OK, output from the virtual arrays. */
++ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
++ ci++, compptr++) {
++ /* Don't bother to IDCT an uninteresting component. */
++ if (!compptr->component_needed)
++ continue;
++ /* Align the virtual buffer for this component. */
++ buffer = (*cinfo->mem->access_virt_barray)
++ ((j_common_ptr)cinfo, coef->whole_image[ci],
++ cinfo->output_iMCU_row * compptr->v_samp_factor,
++ (JDIMENSION)compptr->v_samp_factor, FALSE);
++ /* Count non-dummy DCT block rows in this iMCU row. */
++ if (cinfo->output_iMCU_row < last_iMCU_row)
++ block_rows = compptr->v_samp_factor;
++ 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;
++ }
++ inverse_DCT = cinfo->idct->_inverse_DCT[ci];
++ output_ptr = output_buf[ci];
++ /* Loop over all DCT blocks to be processed. */
++ for (block_row = 0; block_row < block_rows; block_row++) {
++ buffer_ptr = buffer[block_row] + cinfo->master->first_MCU_col[ci];
++ output_col = 0;
++ for (block_num = cinfo->master->first_MCU_col[ci];
++ block_num <= cinfo->master->last_MCU_col[ci]; block_num++) {
++ #ifdef WITH_PROFILE
++ cinfo->master->start = getTime();
++ #endif
++ (*inverse_DCT) (cinfo, compptr, (JCOEFPTR)buffer_ptr, output_ptr,
++ output_col);
++ #ifdef WITH_PROFILE
++ cinfo->master->idct_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->idct_mcoeffs += (double)DCTSIZE2 / 1000000.;
++ #endif
++ buffer_ptr++;
++ output_col += compptr->_DCT_scaled_size;
++ }
++ output_ptr += compptr->_DCT_scaled_size;
++ }
++ }
++
++ if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
++ return JPEG_ROW_COMPLETED;
++ return JPEG_SCAN_COMPLETED;
++ }
++
++ #endif /* D_MULTISCAN_FILES_SUPPORTED */
++
++
++ #ifdef BLOCK_SMOOTHING_SUPPORTED
++
++ /*
++ * This code applies interblock smoothing; the first 9 AC coefficients are
++ * estimated from the DC values of a DCT block and its 24 neighboring blocks.
++ * We apply smoothing only for progressive JPEG decoding, and only if
++ * the coefficients it can estimate are not yet known to full precision.
++ */
++
++ /* Natural-order array positions of the first 9 zigzag-order coefficients */
++ #define Q01_POS 1
++ #define Q10_POS 8
++ #define Q20_POS 16
++ #define Q11_POS 9
++ #define Q02_POS 2
++ #define Q03_POS 3
++ #define Q12_POS 10
++ #define Q21_POS 17
++ #define Q30_POS 24
++
++ /*
++ * 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.
++ */
++
++ LOCAL(boolean)
++ smoothing_ok(j_decompress_ptr cinfo)
++ {
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++ boolean smoothing_useful = FALSE;
++ int ci, coefi;
++ jpeg_component_info *compptr;
++ JQUANT_TBL *qtable;
++ int *coef_bits, *prev_coef_bits;
++ int *coef_bits_latch, *prev_coef_bits_latch;
++
++ if (!cinfo->progressive_mode || cinfo->coef_bits == NULL)
++ return FALSE;
++
++ /* Allocate latch area if not already done */
++ if (coef->coef_bits_latch == NULL)
++ coef->coef_bits_latch = (int *)
++ (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
++ cinfo->num_components * 2 *
++ (SAVED_COEFS * sizeof(int)));
++ coef_bits_latch = coef->coef_bits_latch;
++ prev_coef_bits_latch =
++ &coef->coef_bits_latch[cinfo->num_components * SAVED_COEFS];
++
++ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
++ ci++, compptr++) {
++ /* All components' quantization values must already be latched. */
++ if ((qtable = compptr->quant_table) == NULL)
++ return FALSE;
++ /* Verify DC & first 9 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 ||
++ qtable->quantval[Q03_POS] == 0 ||
++ qtable->quantval[Q12_POS] == 0 ||
++ qtable->quantval[Q21_POS] == 0 ||
++ qtable->quantval[Q30_POS] == 0)
++ return FALSE;
++ /* DC values must be at least partly known for all components. */
++ coef_bits = cinfo->coef_bits[ci];
++ prev_coef_bits = cinfo->coef_bits[ci + cinfo->num_components];
++ if (coef_bits[0] < 0)
++ return FALSE;
++ coef_bits_latch[0] = coef_bits[0];
++ /* Block smoothing is helpful if some AC coefficients remain inaccurate. */
++ for (coefi = 1; coefi < SAVED_COEFS; coefi++) {
++ if (cinfo->input_scan_number > 1)
++ prev_coef_bits_latch[coefi] = prev_coef_bits[coefi];
++ else
++ prev_coef_bits_latch[coefi] = -1;
++ coef_bits_latch[coefi] = coef_bits[coefi];
++ if (coef_bits[coefi] != 0)
++ smoothing_useful = TRUE;
++ }
++ coef_bits_latch += SAVED_COEFS;
++ prev_coef_bits_latch += SAVED_COEFS;
++ }
++
++ return smoothing_useful;
++ }
++
++
++ /*
++ * Variant of decompress_data for use when doing block smoothing.
++ */
++
++ METHODDEF(int)
++ decompress_smooth_data(j_decompress_ptr cinfo, _JSAMPIMAGE output_buf)
++ {
++ my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
++ JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
++ JDIMENSION block_num, last_block_column;
++ int ci, block_row, block_rows, access_rows, image_block_row,
++ image_block_rows;
++ JBLOCKARRAY buffer;
++ JBLOCKROW buffer_ptr, prev_prev_block_row, prev_block_row;
++ JBLOCKROW next_block_row, next_next_block_row;
++ _JSAMPARRAY output_ptr;
++ JDIMENSION output_col;
++ jpeg_component_info *compptr;
++ _inverse_DCT_method_ptr inverse_DCT;
++ boolean change_dc;
++ JCOEF *workspace;
++ int *coef_bits;
++ JQUANT_TBL *quanttbl;
++ JLONG Q00, Q01, Q02, Q03 = 0, Q10, Q11, Q12 = 0, Q20, Q21 = 0, Q30 = 0, num;
++ int DC01, DC02, DC03, DC04, DC05, DC06, DC07, DC08, DC09, DC10, DC11, DC12,
++ DC13, DC14, DC15, DC16, DC17, DC18, DC19, DC20, DC21, DC22, DC23, DC24,
++ DC25;
++ int Al, pred;
++
++ /* Keep a local variable to avoid looking it up more than once */
++ workspace = coef->workspace;
++
++ /* 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 two rows ahead so that next two block rows' DC
++ * values are up to date.
++ */
++ JDIMENSION delta = (cinfo->Ss == 0) ? 2 : 0;
++ if (cinfo->input_iMCU_row > cinfo->output_iMCU_row + delta)
++ break;
++ }
++ if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
++ return JPEG_SUSPENDED;
++ }
++
++ /* OK, output from the virtual arrays. */
++ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
++ ci++, compptr++) {
++ /* Don't bother to IDCT an uninteresting component. */
++ if (!compptr->component_needed)
++ continue;
++ /* Count non-dummy DCT block rows in this iMCU row. */
++ if (cinfo->output_iMCU_row + 1 < last_iMCU_row) {
++ block_rows = compptr->v_samp_factor;
++ access_rows = block_rows * 3; /* this and next two iMCU rows */
++ } else if (cinfo->output_iMCU_row < last_iMCU_row) {
++ block_rows = compptr->v_samp_factor;
++ access_rows = block_rows * 2; /* this and next iMCU row */
++ } 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 */
++ }
++ /* Align the virtual buffer for this component. */
++ if (cinfo->output_iMCU_row > 1) {
++ access_rows += 2 * compptr->v_samp_factor; /* prior two iMCU rows too */
++ buffer = (*cinfo->mem->access_virt_barray)
++ ((j_common_ptr)cinfo, coef->whole_image[ci],
++ (cinfo->output_iMCU_row - 2) * compptr->v_samp_factor,
++ (JDIMENSION)access_rows, FALSE);
++ buffer += 2 * compptr->v_samp_factor; /* point to current iMCU row */
++ } else if (cinfo->output_iMCU_row > 0) {
++ access_rows += compptr->v_samp_factor; /* prior iMCU row too */
++ buffer = (*cinfo->mem->access_virt_barray)
++ ((j_common_ptr)cinfo, coef->whole_image[ci],
++ (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor,
++ (JDIMENSION)access_rows, FALSE);
++ buffer += compptr->v_samp_factor; /* point to current iMCU row */
++ } else {
++ buffer = (*cinfo->mem->access_virt_barray)
++ ((j_common_ptr)cinfo, coef->whole_image[ci],
++ (JDIMENSION)0, (JDIMENSION)access_rows, FALSE);
++ }
++ /* Fetch component-dependent info.
++ * If the current scan is incomplete, then we use the component-dependent
++ * info from the previous scan.
++ */
++ if (cinfo->output_iMCU_row > cinfo->master->last_good_iMCU_row)
++ coef_bits =
++ coef->coef_bits_latch + ((ci + cinfo->num_components) * SAVED_COEFS);
++ else
++ coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
++
++ /* We only do DC interpolation if no AC coefficient data is available. */
++ change_dc =
++ coef_bits[1] == -1 && coef_bits[2] == -1 && coef_bits[3] == -1 &&
++ coef_bits[4] == -1 && coef_bits[5] == -1 && coef_bits[6] == -1 &&
++ coef_bits[7] == -1 && coef_bits[8] == -1 && coef_bits[9] == -1;
++
++ quanttbl = compptr->quant_table;
++ Q00 = quanttbl->quantval[0];
++ Q01 = quanttbl->quantval[Q01_POS];
++ Q10 = quanttbl->quantval[Q10_POS];
++ Q20 = quanttbl->quantval[Q20_POS];
++ Q11 = quanttbl->quantval[Q11_POS];
++ Q02 = quanttbl->quantval[Q02_POS];
++ if (change_dc) {
++ Q03 = quanttbl->quantval[Q03_POS];
++ Q12 = quanttbl->quantval[Q12_POS];
++ Q21 = quanttbl->quantval[Q21_POS];
++ Q30 = quanttbl->quantval[Q30_POS];
++ }
++ inverse_DCT = cinfo->idct->_inverse_DCT[ci];
++ output_ptr = output_buf[ci];
++ /* Loop over all DCT blocks to be processed. */
++ image_block_rows = block_rows * cinfo->total_iMCU_rows;
++ for (block_row = 0; block_row < block_rows; block_row++) {
++ image_block_row = cinfo->output_iMCU_row * block_rows + block_row;
++ buffer_ptr = buffer[block_row] + cinfo->master->first_MCU_col[ci];
++
++ if (image_block_row > 0)
++ prev_block_row =
++ buffer[block_row - 1] + cinfo->master->first_MCU_col[ci];
++ else
++ prev_block_row = buffer_ptr;
++
++ if (image_block_row > 1)
++ prev_prev_block_row =
++ buffer[block_row - 2] + cinfo->master->first_MCU_col[ci];
++ else
++ prev_prev_block_row = prev_block_row;
++
++ if (image_block_row < image_block_rows - 1)
++ next_block_row =
++ buffer[block_row + 1] + cinfo->master->first_MCU_col[ci];
++ else
++ next_block_row = buffer_ptr;
++
++ if (image_block_row < image_block_rows - 2)
++ next_next_block_row =
++ buffer[block_row + 2] + cinfo->master->first_MCU_col[ci];
++ else
++ next_next_block_row = next_block_row;
++
++ /* We fetch the surrounding DC values using a sliding-register approach.
++ * Initialize all 25 here so as to do the right thing on narrow pics.
++ */
++ DC01 = DC02 = DC03 = DC04 = DC05 = (int)prev_prev_block_row[0][0];
++ DC06 = DC07 = DC08 = DC09 = DC10 = (int)prev_block_row[0][0];
++ DC11 = DC12 = DC13 = DC14 = DC15 = (int)buffer_ptr[0][0];
++ DC16 = DC17 = DC18 = DC19 = DC20 = (int)next_block_row[0][0];
++ DC21 = DC22 = DC23 = DC24 = DC25 = (int)next_next_block_row[0][0];
++ output_col = 0;
++ last_block_column = compptr->width_in_blocks - 1;
++ for (block_num = cinfo->master->first_MCU_col[ci];
++ block_num <= cinfo->master->last_MCU_col[ci]; block_num++) {
++ /* Fetch current DCT block into workspace so we can modify it. */
++ jcopy_block_row(buffer_ptr, (JBLOCKROW)workspace, (JDIMENSION)1);
++ /* Update DC values */
++ if (block_num == cinfo->master->first_MCU_col[ci] &&
++ block_num < last_block_column) {
++ DC04 = DC05 = (int)prev_prev_block_row[1][0];
++ DC09 = DC10 = (int)prev_block_row[1][0];
++ DC14 = DC15 = (int)buffer_ptr[1][0];
++ DC19 = DC20 = (int)next_block_row[1][0];
++ DC24 = DC25 = (int)next_next_block_row[1][0];
++ }
++ if (block_num + 1 < last_block_column) {
++ DC05 = (int)prev_prev_block_row[2][0];
++ DC10 = (int)prev_block_row[2][0];
++ DC15 = (int)buffer_ptr[2][0];
++ DC20 = (int)next_block_row[2][0];
++ DC25 = (int)next_next_block_row[2][0];
++ }
++ /* If DC interpolation is enabled, compute coefficient estimates using
++ * a Gaussian-like kernel, keeping the averages of the DC values.
++ *
++ * If DC interpolation is disabled, compute coefficient estimates using
++ * an algorithm similar to the one described in Section K.8 of the JPEG
++ * standard, except applied to a 5x5 window rather than a 3x3 window.
++ *
++ * An estimate is applied only if the coefficient is still zero and is
++ * not known to be fully accurate.
++ */
++ /* AC01 */
++ if ((Al = coef_bits[1]) != 0 && workspace[1] == 0) {
++ num = Q00 * (change_dc ?
++ (-DC01 - DC02 + DC04 + DC05 - 3 * DC06 + 13 * DC07 -
++ 13 * DC09 + 3 * DC10 - 3 * DC11 + 38 * DC12 - 38 * DC14 +
++ 3 * DC15 - 3 * DC16 + 13 * DC17 - 13 * DC19 + 3 * DC20 -
++ DC21 - DC22 + DC24 + DC25) :
++ (-7 * DC11 + 50 * DC12 - 50 * DC14 + 7 * DC15));
++ 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] = (JCOEF)pred;
++ }
++ /* AC10 */
++ if ((Al = coef_bits[2]) != 0 && workspace[8] == 0) {
++ num = Q00 * (change_dc ?
++ (-DC01 - 3 * DC02 - 3 * DC03 - 3 * DC04 - DC05 - DC06 +
++ 13 * DC07 + 38 * DC08 + 13 * DC09 - DC10 + DC16 -
++ 13 * DC17 - 38 * DC18 - 13 * DC19 + DC20 + DC21 +
++ 3 * DC22 + 3 * DC23 + 3 * DC24 + DC25) :
++ (-7 * DC03 + 50 * DC08 - 50 * DC18 + 7 * DC23));
++ 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] = (JCOEF)pred;
++ }
++ /* AC20 */
++ if ((Al = coef_bits[3]) != 0 && workspace[16] == 0) {
++ num = Q00 * (change_dc ?
++ (DC03 + 2 * DC07 + 7 * DC08 + 2 * DC09 - 5 * DC12 - 14 * DC13 -
++ 5 * DC14 + 2 * DC17 + 7 * DC18 + 2 * DC19 + DC23) :
++ (-DC03 + 13 * DC08 - 24 * DC13 + 13 * DC18 - DC23));
++ 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] = (JCOEF)pred;
++ }
++ /* AC11 */
++ if ((Al = coef_bits[4]) != 0 && workspace[9] == 0) {
++ num = Q00 * (change_dc ?
++ (-DC01 + DC05 + 9 * DC07 - 9 * DC09 - 9 * DC17 +
++ 9 * DC19 + DC21 - DC25) :
++ (DC10 + DC16 - 10 * DC17 + 10 * DC19 - DC02 - DC20 + DC22 -
++ DC24 + DC04 - DC06 + 10 * DC07 - 10 * DC09));
++ 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] = (JCOEF)pred;
++ }
++ /* AC02 */
++ if ((Al = coef_bits[5]) != 0 && workspace[2] == 0) {
++ num = Q00 * (change_dc ?
++ (2 * DC07 - 5 * DC08 + 2 * DC09 + DC11 + 7 * DC12 - 14 * DC13 +
++ 7 * DC14 + DC15 + 2 * DC17 - 5 * DC18 + 2 * DC19) :
++ (-DC11 + 13 * DC12 - 24 * DC13 + 13 * DC14 - DC15));
++ 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] = (JCOEF)pred;
++ }
++ if (change_dc) {
++ /* AC03 */
++ if ((Al = coef_bits[6]) != 0 && workspace[3] == 0) {
++ num = Q00 * (DC07 - DC09 + 2 * DC12 - 2 * DC14 + DC17 - DC19);
++ if (num >= 0) {
++ pred = (int)(((Q03 << 7) + num) / (Q03 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ } else {
++ pred = (int)(((Q03 << 7) - num) / (Q03 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ pred = -pred;
++ }
++ workspace[3] = (JCOEF)pred;
++ }
++ /* AC12 */
++ if ((Al = coef_bits[7]) != 0 && workspace[10] == 0) {
++ num = Q00 * (DC07 - 3 * DC08 + DC09 - DC17 + 3 * DC18 - DC19);
++ if (num >= 0) {
++ pred = (int)(((Q12 << 7) + num) / (Q12 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ } else {
++ pred = (int)(((Q12 << 7) - num) / (Q12 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ pred = -pred;
++ }
++ workspace[10] = (JCOEF)pred;
++ }
++ /* AC21 */
++ if ((Al = coef_bits[8]) != 0 && workspace[17] == 0) {
++ num = Q00 * (DC07 - DC09 - 3 * DC12 + 3 * DC14 + DC17 - DC19);
++ if (num >= 0) {
++ pred = (int)(((Q21 << 7) + num) / (Q21 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ } else {
++ pred = (int)(((Q21 << 7) - num) / (Q21 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ pred = -pred;
++ }
++ workspace[17] = (JCOEF)pred;
++ }
++ /* AC30 */
++ if ((Al = coef_bits[9]) != 0 && workspace[24] == 0) {
++ num = Q00 * (DC07 + 2 * DC08 + DC09 - DC17 - 2 * DC18 - DC19);
++ if (num >= 0) {
++ pred = (int)(((Q30 << 7) + num) / (Q30 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ } else {
++ pred = (int)(((Q30 << 7) - num) / (Q30 << 8));
++ if (Al > 0 && pred >= (1 << Al))
++ pred = (1 << Al) - 1;
++ pred = -pred;
++ }
++ workspace[24] = (JCOEF)pred;
++ }
++ /* coef_bits[0] is non-negative. Otherwise this function would not
++ * be called.
++ */
++ num = Q00 *
++ (-2 * DC01 - 6 * DC02 - 8 * DC03 - 6 * DC04 - 2 * DC05 -
++ 6 * DC06 + 6 * DC07 + 42 * DC08 + 6 * DC09 - 6 * DC10 -
++ 8 * DC11 + 42 * DC12 + 152 * DC13 + 42 * DC14 - 8 * DC15 -
++ 6 * DC16 + 6 * DC17 + 42 * DC18 + 6 * DC19 - 6 * DC20 -
++ 2 * DC21 - 6 * DC22 - 8 * DC23 - 6 * DC24 - 2 * DC25);
++ if (num >= 0) {
++ pred = (int)(((Q00 << 7) + num) / (Q00 << 8));
++ } else {
++ pred = (int)(((Q00 << 7) - num) / (Q00 << 8));
++ pred = -pred;
++ }
++ workspace[0] = (JCOEF)pred;
++ } /* change_dc */
++
++ /* OK, do the IDCT */
++ #ifdef WITH_PROFILE
++ cinfo->master->start = getTime();
++ #endif
++ (*inverse_DCT) (cinfo, compptr, (JCOEFPTR)workspace, output_ptr,
++ output_col);
++ #ifdef WITH_PROFILE
++ cinfo->master->idct_elapsed += getTime() - cinfo->master->start;
++ cinfo->master->idct_mcoeffs += (double)DCTSIZE2 / 1000000.;
++ #endif
++ /* Advance for next column */
++ DC01 = DC02; DC02 = DC03; DC03 = DC04; DC04 = DC05;
++ DC06 = DC07; DC07 = DC08; DC08 = DC09; DC09 = DC10;
++ DC11 = DC12; DC12 = DC13; DC13 = DC14; DC14 = DC15;
++ DC16 = DC17; DC17 = DC18; DC18 = DC19; DC19 = DC20;
++ DC21 = DC22; DC22 = DC23; DC23 = DC24; DC24 = DC25;
++ buffer_ptr++, prev_block_row++, next_block_row++,
++ prev_prev_block_row++, next_next_block_row++;
++ output_col += compptr->_DCT_scaled_size;
++ }
++ output_ptr += compptr->_DCT_scaled_size;
++ }
++ }
++
++ if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
++ return JPEG_ROW_COMPLETED;
++ return JPEG_SCAN_COMPLETED;
++ }
++
++ #endif /* BLOCK_SMOOTHING_SUPPORTED */
++
++
++ /*
++ * Initialize coefficient buffer controller.
++ */
++
++ GLOBAL(void)
++ _jinit_d_coef_controller(j_decompress_ptr cinfo, boolean need_full_buffer)
++ {
++ my_coef_ptr coef;
++
++ if (cinfo->data_precision != BITS_IN_JSAMPLE)
++ ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
++
++ coef = (my_coef_ptr)
++ (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
++ sizeof(my_coef_controller));
++ memset(coef, 0, sizeof(my_coef_controller));
++ cinfo->coef = (struct jpeg_d_coef_controller *)coef;
++ coef->pub.start_input_pass = start_input_pass;
++ coef->pub.start_output_pass = start_output_pass;
++ #ifdef BLOCK_SMOOTHING_SUPPORTED
++ coef->coef_bits_latch = NULL;
++ #endif
++
++ /* Create the coefficient buffer. */
++ if (need_full_buffer) {
++ #ifdef D_MULTISCAN_FILES_SUPPORTED
++ /* Allocate a full-image virtual array for each component, */
++ /* padded to a multiple of samp_factor DCT blocks in each direction. */
++ /* Note we ask for a pre-zeroed array. */
++ int ci, access_rows;
++ jpeg_component_info *compptr;
++
++ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
++ ci++, compptr++) {
++ access_rows = compptr->v_samp_factor;
++ #ifdef BLOCK_SMOOTHING_SUPPORTED
++ /* If block smoothing could be used, need a bigger window */
++ if (cinfo->progressive_mode)
++ access_rows *= 5;
++ #endif
++ coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
++ ((j_common_ptr)cinfo, JPOOL_IMAGE, TRUE,
++ (JDIMENSION)jround_up((long)compptr->width_in_blocks,
++ (long)compptr->h_samp_factor),
++ (JDIMENSION)jround_up((long)compptr->height_in_blocks,
++ (long)compptr->v_samp_factor),
++ (JDIMENSION)access_rows);
++ }
++ coef->pub.consume_data = consume_data;
++ coef->pub._decompress_data = decompress_data;
++ coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */
++ #else
++ ERREXIT(cinfo, JERR_NOT_COMPILED);
++ #endif
++ } else {
++ /* We only need a single-MCU buffer. */
++ JBLOCKROW buffer;
++ int i;
++
++ buffer = (JBLOCKROW)
++ (*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE,
++ D_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK));
++ for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) {
++ coef->MCU_buffer[i] = buffer + i;
++ }
++ coef->pub.consume_data = dummy_consume_data;
++ coef->pub._decompress_data = decompress_onepass;
++ coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */
++ }
++
++ /* Allocate the workspace buffer */
++ coef->workspace = (JCOEF *)
++ (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
++ sizeof(JCOEF) * DCTSIZE2);
++ }