| /* |
| * 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, D. R. Commander. |
| * Copyright (C) 2015, 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->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++; |
| } |
| } |
| } |
| /* 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 as described by section K.8 |
| * of the JPEG standard: the first 5 AC coefficients are estimated from |
| * the DC values of a DCT block and its 8 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 5 zigzag-order coefficients */ |
| #define Q01_POS 1 |
| #define Q10_POS 8 |
| #define Q20_POS 16 |
| #define Q11_POS 9 |
| #define Q02_POS 2 |
| |
| /* |
| * 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; |
| int *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 * |
| (SAVED_COEFS * sizeof(int))); |
| coef_bits_latch = coef->coef_bits_latch; |
| |
| 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 5 AC quantizers are nonzero to avoid zero-divide. */ |
| if (qtable->quantval[0] == 0 || |
| qtable->quantval[Q01_POS] == 0 || |
| qtable->quantval[Q10_POS] == 0 || |
| qtable->quantval[Q20_POS] == 0 || |
| qtable->quantval[Q11_POS] == 0 || |
| qtable->quantval[Q02_POS] == 0) |
| return FALSE; |
| /* DC values must be at least partly known for all components. */ |
| coef_bits = cinfo->coef_bits[ci]; |
| if (coef_bits[0] < 0) |
| return FALSE; |
| /* Block smoothing is helpful if some AC coefficients remain inaccurate. */ |
| for (coefi = 1; coefi <= 5; coefi++) { |
| coef_bits_latch[coefi] = coef_bits[coefi]; |
| if (coef_bits[coefi] != 0) |
| smoothing_useful = TRUE; |
| } |
| 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_block_row, next_block_row; |
| JSAMPARRAY output_ptr; |
| JDIMENSION output_col; |
| jpeg_component_info *compptr; |
| inverse_DCT_method_ptr inverse_DCT; |
| boolean first_row, last_row; |
| JCOEF *workspace; |
| int *coef_bits; |
| JQUANT_TBL *quanttbl; |
| JLONG Q00,Q01,Q02,Q10,Q11,Q20, num; |
| int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9; |
| 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 one row ahead so that next block row's DC |
| * values are up to date. |
| */ |
| JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 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 < last_iMCU_row) { |
| block_rows = compptr->v_samp_factor; |
| access_rows = block_rows * 2; /* this and next iMCU row */ |
| last_row = FALSE; |
| } else { |
| /* NB: can't use last_row_height here; it is input-side-dependent! */ |
| block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); |
| if (block_rows == 0) block_rows = compptr->v_samp_factor; |
| access_rows = block_rows; /* this iMCU row only */ |
| last_row = TRUE; |
| } |
| /* Align the virtual buffer for this component. */ |
| 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 */ |
| first_row = FALSE; |
| } else { |
| buffer = (*cinfo->mem->access_virt_barray) |
| ((j_common_ptr) cinfo, coef->whole_image[ci], |
| (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE); |
| first_row = TRUE; |
| } |
| /* Fetch component-dependent info */ |
| coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS); |
| 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]; |
| 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 (first_row && block_row == 0) |
| prev_block_row = buffer_ptr; |
| else |
| prev_block_row = buffer[block_row-1]; |
| if (last_row && block_row == block_rows-1) |
| next_block_row = buffer_ptr; |
| else |
| next_block_row = buffer[block_row+1]; |
| /* We fetch the surrounding DC values using a sliding-register approach. |
| * Initialize all nine here so as to do the right thing on narrow pics. |
| */ |
| DC1 = DC2 = DC3 = (int) prev_block_row[0][0]; |
| DC4 = DC5 = DC6 = (int) buffer_ptr[0][0]; |
| DC7 = DC8 = DC9 = (int) next_block_row[0][0]; |
| 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 < last_block_column) { |
| DC3 = (int) prev_block_row[1][0]; |
| DC6 = (int) buffer_ptr[1][0]; |
| DC9 = (int) next_block_row[1][0]; |
| } |
| /* Compute coefficient estimates per K.8. |
| * An estimate is applied only if coefficient is still zero, |
| * and is not known to be fully accurate. |
| */ |
| /* AC01 */ |
| if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) { |
| num = 36 * Q00 * (DC4 - DC6); |
| 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 = 36 * Q00 * (DC2 - DC8); |
| 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 = 9 * Q00 * (DC2 + DC8 - 2*DC5); |
| 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 = 5 * Q00 * (DC1 - DC3 - DC7 + DC9); |
| 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 = 9 * Q00 * (DC4 + DC6 - 2*DC5); |
| 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; |
| } |
| /* OK, do the IDCT */ |
| (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace, |
| output_ptr, output_col); |
| /* Advance for next column */ |
| DC1 = DC2; DC2 = DC3; |
| DC4 = DC5; DC5 = DC6; |
| DC7 = DC8; DC8 = DC9; |
| buffer_ptr++, prev_block_row++, 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 *= 3; |
| #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); |
| } |
