| /* |
| * 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, 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 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 "jpegcomp.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; |
| 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) { |
| 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. */ |
| for (block_row = 0; block_row < block_rows; block_row++) { |
| buffer_ptr = buffer[block_row] + cinfo->master->first_MCU_col[ci]; |
| |
| if (block_row > 0 || cinfo->output_iMCU_row > 0) |
| prev_block_row = |
| buffer[block_row - 1] + cinfo->master->first_MCU_col[ci]; |
| else |
| prev_block_row = buffer_ptr; |
| |
| if (block_row > 1 || cinfo->output_iMCU_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 (block_row < block_rows - 1 || cinfo->output_iMCU_row < last_iMCU_row) |
| next_block_row = |
| buffer[block_row + 1] + cinfo->master->first_MCU_col[ci]; |
| else |
| next_block_row = buffer_ptr; |
| |
| if (block_row < block_rows - 2 || |
| cinfo->output_iMCU_row + 1 < last_iMCU_row) |
| 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 = (int)prev_prev_block_row[1][0]; |
| DC09 = (int)prev_block_row[1][0]; |
| DC14 = (int)buffer_ptr[1][0]; |
| DC19 = (int)next_block_row[1][0]; |
| DC24 = (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; |
| |
| 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); |
| } |
