/*

* jdcoefct.c

*

* Copyright (C) 1994-1997, Thomas G. Lane.

* Modified 2002-2011 by Guido Vollbeding.

* 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. */

if (cinfo->lim_Se) /* can bypass in DC only case */

FMEMZERO((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_v_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_h_scaled_size;

}

}

blkn += compptr->MCU_width;

output_ptr += compptr->DCT_v_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_h_scaled_size;

}

output_ptr += compptr->DCT_v_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<<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_h_scaled_size;

}

output_ptr += compptr->DCT_v_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;

}

if (cinfo->lim_Se == 0) /* DC only case: want to bypass later */

FMEMZERO((void FAR *) buffer,

(size_t) (D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)));

coef->pub.consume_data = dummy_consume_data;

coef->pub.decompress_data = decompress_onepass;

coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */

}

}