#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* 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<<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 */ | |
} | |
} | |
#endif //_FX_JPEG_TURBO_ |