/* * jdcoefct.c * * Copyright (C) 1994-1997, Thomas G. Lane. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README 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. */ #define JPEG_INTERNALS #include "jinclude.h" #include "jpeglib.h" /* Block smoothing is only applicable for progressive JPEG, so: */ #ifndef D_PROGRESSIVE_SUPPORTED #undef BLOCK_SMOOTHING_SUPPORTED #endif /* Private buffer controller object */ typedef struct { struct jpeg_d_coef_controller pub; /* public fields */ /* These variables keep track of the current location of the input side. */ /* cinfo->input_iMCU_row is also used for this. */ JDIMENSION MCU_ctr; /* counts MCUs processed in current row */ int MCU_vert_offset; /* counts MCU rows within iMCU row */ int MCU_rows_per_iMCU_row; /* number of such rows needed */ /* The output side's location is represented by cinfo->output_iMCU_row. */ /* In single-pass modes, it's sufficient to buffer just one MCU. * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks, * and let the entropy decoder write into that workspace each time. * (On 80x86, the workspace is FAR even though it's not really very big; * this is to keep the module interfaces unchanged when a large coefficient * buffer is necessary.) * In multi-pass modes, this array points to the current MCU's blocks * within the virtual arrays; it is used only by the input side. */ JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU]; #ifdef D_MULTISCAN_FILES_SUPPORTED /* In multi-pass modes, we need a virtual block array for each component. */ jvirt_barray_ptr whole_image[MAX_COMPONENTS]; #endif #ifdef BLOCK_SMOOTHING_SUPPORTED /* When doing block smoothing, we latch coefficient Al values here */ int * coef_bits_latch; #define SAVED_COEFS 6 /* we save coef_bits[0..5] */ #endif } my_coef_controller; typedef my_coef_controller * my_coef_ptr; /* Forward declarations */ METHODDEF(int) decompress_onepass JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); #ifdef D_MULTISCAN_FILES_SUPPORTED METHODDEF(int) decompress_data JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); #endif #ifdef BLOCK_SMOOTHING_SUPPORTED LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo)); METHODDEF(int) decompress_smooth_data JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); #endif LOCAL(void) start_iMCU_row (j_decompress_ptr cinfo) /* Reset within-iMCU-row counters for a new row (input side) */ { my_coef_ptr coef = (my_coef_ptr) cinfo->coef; /* In an interleaved scan, an MCU row is the same as an iMCU row. * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. * But at the bottom of the image, process only what's left. */ if (cinfo->comps_in_scan > 1) { coef->MCU_rows_per_iMCU_row = 1; } else { if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1)) coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; else coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; } coef->MCU_ctr = 0; coef->MCU_vert_offset = 0; } /* * 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 FAR *) 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; } /* 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 * 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]; output_col = 0; for (block_num = 0; block_num < compptr->width_in_blocks; 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; JBLOCK workspace; int *coef_bits; JQUANT_TBL *quanttbl; INT32 Q00,Q01,Q02,Q10,Q11,Q20, num; int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9; int Al, pred; /* 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]; 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 = 0; block_num <= last_block_column; 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< 0 && pred >= (1<= 0) { pred = (int) (((Q10<<7) + num) / (Q10<<8)); if (Al > 0 && pred >= (1< 0 && pred >= (1<= 0) { pred = (int) (((Q20<<7) + num) / (Q20<<8)); if (Al > 0 && pred >= (1< 0 && pred >= (1<= 0) { pred = (int) (((Q11<<7) + num) / (Q11<<8)); if (Al > 0 && pred >= (1< 0 && pred >= (1<= 0) { pred = (int) (((Q02<<7) + num) / (Q02<<8)); if (Al > 0 && pred >= (1< 0 && pred >= (1<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 */ } }