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JD2022-TU1/main/extern/CaptureJpeg/Source/JDCOEFCT.cpp

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// * jdcoefct.c
// *
// * Copyright (C) 1994-1995, 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.
// * For single pass, this is the same as the components in the scan.
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[ci] + 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.
// * 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.
for (coefi = 0; coefi <= 5; coefi++) {
if (qtable->quantval[coefi] == 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[1];
Q10 = quanttbl->quantval[2];
Q20 = quanttbl->quantval[3];
Q11 = quanttbl->quantval[4];
Q02 = quanttbl->quantval[5];
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<<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
}
}
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