/* * 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 for Cendio AB * Copyright (C) 2010, 2015-2016, 2019-2020, 2022-2023, 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" /* 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; 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; return JPEG_SUSPENDED; } /* 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++) { (*inverse_DCT) (cinfo, compptr, (JCOEFPTR)coef->MCU_buffer[blkn + xindex], output_ptr, output_col); 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. */ 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; return JPEG_SUSPENDED; } } /* 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++) { (*inverse_DCT) (cinfo, compptr, (JCOEFPTR)buffer_ptr, output_ptr, output_col); 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 */ (*inverse_DCT) (cinfo, compptr, (JCOEFPTR)workspace, output_ptr, output_col); /* 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)); 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); }