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doom3-bfg/neo/libs/jpeg-6/jdcoefct.cpp
Robert Beckebans c2f45c550c Moved third-party libs to libs/
2012-11-27 21:26:06 +01:00

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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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