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4a6b730364
libjpeg-turbo/jdpipe.c
Thomas G. Lane 4a6b730364 The Independent JPEG Group's JPEG software v3
2015-07-29 15:21:19 -05:00

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/*
* jdpipe.c
*
* Copyright (C) 1991, 1992, 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 decompression pipeline controllers.
* These routines are invoked via the d_pipeline_controller method.
*
* There are two basic pipeline controllers. The simpler one handles a
* single-scan JPEG file (single component or fully interleaved) with no
* color quantization or 1-pass quantization. In this case, the file can
* be processed in one top-to-bottom pass. The more complex controller is
* used when 2-pass color quantization is requested and/or the JPEG file
* has multiple scans (noninterleaved or partially interleaved). In this
* case, the entire image must be buffered up in a "big" array.
*
* If you need to make a minimal implementation, the more complex controller
* can be compiled out by disabling the appropriate configuration options.
* We don't recommend this, since then you can't handle all legal JPEG files.
*/
#include "jinclude.h"
#ifdef MULTISCAN_FILES_SUPPORTED /* wish we could assume ANSI's defined() */
#define NEED_COMPLEX_CONTROLLER
#else
#ifdef QUANT_2PASS_SUPPORTED
#define NEED_COMPLEX_CONTROLLER
#endif
#endif
/*
* About the data structures:
*
* The processing chunk size for unsubsampling is referred to in this file as
* a "row group": a row group is defined as Vk (v_samp_factor) sample rows of
* any component while subsampled, or Vmax (max_v_samp_factor) unsubsampled
* rows. In an interleaved scan each MCU row contains exactly DCTSIZE row
* groups of each component in the scan. In a noninterleaved scan an MCU row
* is one row of blocks, which might not be an integral number of row groups;
* therefore, we read in Vk MCU rows to obtain the same amount of data as we'd
* have in an interleaved scan.
* To provide context for the unsubsampling step, we have to retain the last
* two row groups of the previous MCU row while reading in the next MCU row
* (or set of Vk MCU rows). To do this without copying data about, we create
* a rather strange data structure. Exactly DCTSIZE+2 row groups of samples
* are allocated, but we create two different sets of pointers to this array.
* The second set swaps the last two pairs of row groups. By working
* alternately with the two sets of pointers, we can access the data in the
* desired order.
*
* Cross-block smoothing also needs context above and below the "current" row.
* Since this is an optional feature, I've implemented it in a way that is
* much simpler but requires more than the minimum amount of memory. We
* simply allocate three extra MCU rows worth of coefficient blocks and use
* them to "read ahead" one MCU row in the file. For a typical 1000-pixel-wide
* image with 2x2,1x1,1x1 sampling, each MCU row is about 50Kb; an 80x86
* machine may be unable to apply cross-block smoothing to wider images.
*/
/*
* These variables are logically local to the pipeline controller,
* but we make them static so that scan_big_image can use them
* without having to pass them through the quantization routines.
*/
static int rows_in_mem; /* # of sample rows in full-size buffers */
/* Work buffer for data being passed to output module. */
/* This has color_out_comps components if not quantizing, */
/* but only one component when quantizing. */
static JSAMPIMAGE output_workspace;
#ifdef NEED_COMPLEX_CONTROLLER
/* Full-size image array holding desubsampled, but not color-processed data. */
static big_sarray_ptr *fullsize_image;
static JSAMPIMAGE fullsize_ptrs; /* workspace for access_big_sarray() result */
#endif
/*
* Utility routines: common code for pipeline controllers
*/
LOCAL void
interleaved_scan_setup (decompress_info_ptr cinfo)
/* Compute all derived info for an interleaved (multi-component) scan */
/* On entry, cinfo->comps_in_scan and cinfo->cur_comp_info[] are set up */
{
short ci, mcublks;
jpeg_component_info *compptr;
if (cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
ERREXIT(cinfo->emethods, "Too many components for interleaved scan");
cinfo->MCUs_per_row = (cinfo->image_width
+ cinfo->max_h_samp_factor*DCTSIZE - 1)
/ (cinfo->max_h_samp_factor*DCTSIZE);
cinfo->MCU_rows_in_scan = (cinfo->image_height
+ cinfo->max_v_samp_factor*DCTSIZE - 1)
/ (cinfo->max_v_samp_factor*DCTSIZE);
cinfo->blocks_in_MCU = 0;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* for interleaved scan, sampling factors give # of blocks per component */
compptr->MCU_width = compptr->h_samp_factor;
compptr->MCU_height = compptr->v_samp_factor;
compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
/* compute physical dimensions of component */
compptr->subsampled_width = jround_up(compptr->true_comp_width,
(long) (compptr->MCU_width*DCTSIZE));
compptr->subsampled_height = jround_up(compptr->true_comp_height,
(long) (compptr->MCU_height*DCTSIZE));
/* Sanity check */
if (compptr->subsampled_width !=
(cinfo->MCUs_per_row * (compptr->MCU_width*DCTSIZE)))
ERREXIT(cinfo->emethods, "I'm confused about the image width");
/* Prepare array describing MCU composition */
mcublks = compptr->MCU_blocks;
if (cinfo->blocks_in_MCU + mcublks > MAX_BLOCKS_IN_MCU)
ERREXIT(cinfo->emethods, "Sampling factors too large for interleaved scan");
while (mcublks-- > 0) {
cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
}
}
(*cinfo->methods->d_per_scan_method_selection) (cinfo);
}
LOCAL void
noninterleaved_scan_setup (decompress_info_ptr cinfo)
/* Compute all derived info for a noninterleaved (single-component) scan */
/* On entry, cinfo->comps_in_scan = 1 and cinfo->cur_comp_info[0] is set up */
{
jpeg_component_info *compptr = cinfo->cur_comp_info[0];
/* for noninterleaved scan, always one block per MCU */
compptr->MCU_width = 1;
compptr->MCU_height = 1;
compptr->MCU_blocks = 1;
/* compute physical dimensions of component */
compptr->subsampled_width = jround_up(compptr->true_comp_width,
(long) DCTSIZE);
compptr->subsampled_height = jround_up(compptr->true_comp_height,
(long) DCTSIZE);
cinfo->MCUs_per_row = compptr->subsampled_width / DCTSIZE;
cinfo->MCU_rows_in_scan = compptr->subsampled_height / DCTSIZE;
/* Prepare array describing MCU composition */
cinfo->blocks_in_MCU = 1;
cinfo->MCU_membership[0] = 0;
(*cinfo->methods->d_per_scan_method_selection) (cinfo);
}
LOCAL JSAMPIMAGE
alloc_sampimage (decompress_info_ptr cinfo,
int num_comps, long num_rows, long num_cols)
/* Allocate an in-memory sample image (all components same size) */
{
JSAMPIMAGE image;
int ci;
image = (JSAMPIMAGE) (*cinfo->emethods->alloc_small)
(num_comps * SIZEOF(JSAMPARRAY));
for (ci = 0; ci < num_comps; ci++) {
image[ci] = (*cinfo->emethods->alloc_small_sarray) (num_cols, num_rows);
}
return image;
}
#if 0 /* this routine not currently needed */
LOCAL void
free_sampimage (decompress_info_ptr cinfo, JSAMPIMAGE image, int num_comps)
/* Release a sample image created by alloc_sampimage */
{
int ci;
for (ci = 0; ci < num_comps; ci++) {
(*cinfo->emethods->free_small_sarray) (image[ci]);
}
(*cinfo->emethods->free_small) ((void *) image);
}
#endif
LOCAL JBLOCKIMAGE
alloc_MCU_row (decompress_info_ptr cinfo)
/* Allocate one MCU row's worth of coefficient blocks */
{
JBLOCKIMAGE image;
int ci;
image = (JBLOCKIMAGE) (*cinfo->emethods->alloc_small)
(cinfo->comps_in_scan * SIZEOF(JBLOCKARRAY));
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
image[ci] = (*cinfo->emethods->alloc_small_barray)
(cinfo->cur_comp_info[ci]->subsampled_width / DCTSIZE,
(long) cinfo->cur_comp_info[ci]->MCU_height);
}
return image;
}
#ifdef NEED_COMPLEX_CONTROLLER /* not used by simple controller */
LOCAL void
free_MCU_row (decompress_info_ptr cinfo, JBLOCKIMAGE image)
/* Release a coefficient block array created by alloc_MCU_row */
{
int ci;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
(*cinfo->emethods->free_small_barray) (image[ci]);
}
(*cinfo->emethods->free_small) ((void *) image);
}
#endif
LOCAL void
alloc_sampling_buffer (decompress_info_ptr cinfo, JSAMPIMAGE subsampled_data[2])
/* Create a subsampled-data buffer having the desired structure */
/* (see comments at head of file) */
{
short ci, vs, i;
/* Get top-level space for array pointers */
subsampled_data[0] = (JSAMPIMAGE) (*cinfo->emethods->alloc_small)
(cinfo->comps_in_scan * SIZEOF(JSAMPARRAY));
subsampled_data[1] = (JSAMPIMAGE) (*cinfo->emethods->alloc_small)
(cinfo->comps_in_scan * SIZEOF(JSAMPARRAY));
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
vs = cinfo->cur_comp_info[ci]->v_samp_factor; /* row group height */
/* Allocate the real storage */
subsampled_data[0][ci] = (*cinfo->emethods->alloc_small_sarray)
(cinfo->cur_comp_info[ci]->subsampled_width,
(long) (vs * (DCTSIZE+2)));
/* Create space for the scrambled-order pointers */
subsampled_data[1][ci] = (JSAMPARRAY) (*cinfo->emethods->alloc_small)
(vs * (DCTSIZE+2) * SIZEOF(JSAMPROW));
/* Duplicate the first DCTSIZE-2 row groups */
for (i = 0; i < vs * (DCTSIZE-2); i++) {
subsampled_data[1][ci][i] = subsampled_data[0][ci][i];
}
/* Copy the last four row groups in swapped order */
for (i = 0; i < vs * 2; i++) {
subsampled_data[1][ci][vs*DCTSIZE + i] = subsampled_data[0][ci][vs*(DCTSIZE-2) + i];
subsampled_data[1][ci][vs*(DCTSIZE-2) + i] = subsampled_data[0][ci][vs*DCTSIZE + i];
}
}
}
#ifdef NEED_COMPLEX_CONTROLLER /* not used by simple controller */
LOCAL void
free_sampling_buffer (decompress_info_ptr cinfo, JSAMPIMAGE subsampled_data[2])
/* Release a sampling buffer created by alloc_sampling_buffer */
{
short ci;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
/* Free the real storage */
(*cinfo->emethods->free_small_sarray) (subsampled_data[0][ci]);
/* Free the scrambled-order pointers */
(*cinfo->emethods->free_small) ((void *) subsampled_data[1][ci]);
}
/* Free the top-level space */
(*cinfo->emethods->free_small) ((void *) subsampled_data[0]);
(*cinfo->emethods->free_small) ((void *) subsampled_data[1]);
}
#endif
LOCAL void
duplicate_row (JSAMPARRAY image_data,
long num_cols, int source_row, int num_rows)
/* Duplicate the source_row at source_row+1 .. source_row+num_rows */
/* This happens only at the bottom of the image, */
/* so it needn't be super-efficient */
{
register int row;
for (row = 1; row <= num_rows; row++) {
jcopy_sample_rows(image_data, source_row, image_data, source_row + row,
1, num_cols);
}
}
LOCAL void
expand (decompress_info_ptr cinfo,
JSAMPIMAGE subsampled_data, JSAMPIMAGE fullsize_data,
long fullsize_width,
short above, short current, short below, short out)
/* Do unsubsampling expansion of a single row group (of each component). */
/* above, current, below are indexes of row groups in subsampled_data; */
/* out is the index of the target row group in fullsize_data. */
/* Special case: above, below can be -1 to indicate top, bottom of image. */
{
jpeg_component_info *compptr;
JSAMPARRAY above_ptr, below_ptr;
JSAMPROW dummy[MAX_SAMP_FACTOR]; /* for subsample expansion at top/bottom */
short ci, vs, i;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
vs = compptr->v_samp_factor; /* row group height */
if (above >= 0)
above_ptr = subsampled_data[ci] + above * vs;
else {
/* Top of image: make a dummy above-context with copies of 1st row */
/* We assume current=0 in this case */
for (i = 0; i < vs; i++)
dummy[i] = subsampled_data[ci][0];
above_ptr = (JSAMPARRAY) dummy; /* possible near->far pointer conv */
}
if (below >= 0)
below_ptr = subsampled_data[ci] + below * vs;
else {
/* Bot of image: make a dummy below-context with copies of last row */
for (i = 0; i < vs; i++)
dummy[i] = subsampled_data[ci][(current+1)*vs-1];
below_ptr = (JSAMPARRAY) dummy; /* possible near->far pointer conv */
}
(*cinfo->methods->unsubsample[ci])
(cinfo, (int) ci,
compptr->subsampled_width, (int) vs,
fullsize_width, (int) cinfo->max_v_samp_factor,
above_ptr,
subsampled_data[ci] + current * vs,
below_ptr,
fullsize_data[ci] + out * cinfo->max_v_samp_factor);
}
}
LOCAL void
emit_1pass (decompress_info_ptr cinfo, int num_rows, JSAMPIMAGE fullsize_data,
JSAMPARRAY dummy)
/* Do color processing and output of num_rows full-size rows. */
/* This is not used when doing 2-pass color quantization. */
/* The dummy argument simply lets this be called via scan_big_image. */
{
if (cinfo->quantize_colors) {
(*cinfo->methods->color_quantize) (cinfo, num_rows, fullsize_data,
output_workspace[0]);
} else {
(*cinfo->methods->color_convert) (cinfo, num_rows, cinfo->image_width,
fullsize_data, output_workspace);
}
(*cinfo->methods->put_pixel_rows) (cinfo, num_rows, output_workspace);
}
/*
* Support routines for complex controller.
*/
#ifdef NEED_COMPLEX_CONTROLLER
METHODDEF void
scan_big_image (decompress_info_ptr cinfo, quantize_method_ptr quantize_method)
/* Apply quantize_method to entire image stored in fullsize_image[]. */
/* This is the "iterator" routine used by the 2-pass color quantizer. */
/* We also use it directly in some cases. */
{
long pixel_rows_output;
short ci;
for (pixel_rows_output = 0; pixel_rows_output < cinfo->image_height;
pixel_rows_output += rows_in_mem) {
(*cinfo->methods->progress_monitor) (cinfo, pixel_rows_output,
cinfo->image_height);
/* Realign the big buffers */
for (ci = 0; ci < cinfo->num_components; ci++) {
fullsize_ptrs[ci] = (*cinfo->emethods->access_big_sarray)
(fullsize_image[ci], pixel_rows_output, FALSE);
}
/* Let the quantizer have its way with the data.
* Note that output_workspace is simply workspace for the quantizer;
* when it's ready to output, it must call put_pixel_rows itself.
*/
(*quantize_method) (cinfo,
(int) MIN((long) rows_in_mem,
cinfo->image_height - pixel_rows_output),
fullsize_ptrs, output_workspace[0]);
}
cinfo->completed_passes++;
}
#endif /* NEED_COMPLEX_CONTROLLER */
/*
* Support routines for cross-block smoothing.
*/
#ifdef BLOCK_SMOOTHING_SUPPORTED
LOCAL void
smooth_mcu_row (decompress_info_ptr cinfo,
JBLOCKIMAGE above, JBLOCKIMAGE input, JBLOCKIMAGE below,
JBLOCKIMAGE output)
/* Apply cross-block smoothing to one MCU row's worth of coefficient blocks. */
/* above,below are NULL if at top/bottom of image. */
{
jpeg_component_info *compptr;
short ci, ri, last;
JBLOCKROW prev;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
last = compptr->MCU_height - 1;
if (above == NULL)
prev = NULL;
else
prev = above[ci][last];
for (ri = 0; ri < last; ri++) {
(*cinfo->methods->smooth_coefficients) (cinfo, compptr,
prev, input[ci][ri], input[ci][ri+1],
output[ci][ri]);
prev = input[ci][ri];
}
if (below == NULL)
(*cinfo->methods->smooth_coefficients) (cinfo, compptr,
prev, input[ci][last], (JBLOCKROW) NULL,
output[ci][last]);
else
(*cinfo->methods->smooth_coefficients) (cinfo, compptr,
prev, input[ci][last], below[ci][0],
output[ci][last]);
}
}
LOCAL void
get_smoothed_row (decompress_info_ptr cinfo, JBLOCKIMAGE coeff_data,
JBLOCKIMAGE bsmooth[3], int * whichb, long cur_mcu_row)
/* Get an MCU row of coefficients, applying cross-block smoothing. */
/* The output row is placed in coeff_data. bsmooth and whichb hold */
/* working state, and cur_row is needed to check for image top/bottom. */
/* This routine just takes care of the buffering logic. */
{
int prev, cur, next;
/* Special case for top of image: need to pre-fetch a row & init whichb */
if (cur_mcu_row == 0) {
(*cinfo->methods->disassemble_MCU) (cinfo, bsmooth[0]);
if (cinfo->MCU_rows_in_scan > 1) {
(*cinfo->methods->disassemble_MCU) (cinfo, bsmooth[1]);
smooth_mcu_row(cinfo, (JBLOCKIMAGE) NULL, bsmooth[0], bsmooth[1],
coeff_data);
} else {
smooth_mcu_row(cinfo, (JBLOCKIMAGE) NULL, bsmooth[0], (JBLOCKIMAGE) NULL,
coeff_data);
}
*whichb = 1; /* points to next bsmooth[] element to use */
return;
}
cur = *whichb; /* set up references */
prev = (cur == 0 ? 2 : cur - 1);
next = (cur == 2 ? 0 : cur + 1);
*whichb = next; /* advance whichb for next time */
/* Special case for bottom of image: don't read another row */
if (cur_mcu_row >= cinfo->MCU_rows_in_scan - 1) {
smooth_mcu_row(cinfo, bsmooth[prev], bsmooth[cur], (JBLOCKIMAGE) NULL,
coeff_data);
return;
}
/* Normal case: read ahead a new row, smooth the one I got before */
(*cinfo->methods->disassemble_MCU) (cinfo, bsmooth[next]);
smooth_mcu_row(cinfo, bsmooth[prev], bsmooth[cur], bsmooth[next],
coeff_data);
}
#endif /* BLOCK_SMOOTHING_SUPPORTED */
/*
* Decompression pipeline controller used for single-scan files
* without 2-pass color quantization.
*/
METHODDEF void
simple_dcontroller (decompress_info_ptr cinfo)
{
long fullsize_width; /* # of samples per row in full-size buffers */
long cur_mcu_row; /* counts # of MCU rows processed */
long pixel_rows_output; /* # of pixel rows actually emitted */
int mcu_rows_per_loop; /* # of MCU rows processed per outer loop */
/* Work buffer for dequantized coefficients (IDCT input) */
JBLOCKIMAGE coeff_data;
/* Work buffer for cross-block smoothing input */
#ifdef BLOCK_SMOOTHING_SUPPORTED
JBLOCKIMAGE bsmooth[3]; /* this is optional */
int whichb;
#endif
/* Work buffer for subsampled image data (see comments at head of file) */
JSAMPIMAGE subsampled_data[2];
/* Work buffer for desubsampled data */
JSAMPIMAGE fullsize_data;
int whichss, ri;
short i;
/* Compute dimensions of full-size pixel buffers */
/* Note these are the same whether interleaved or not. */
rows_in_mem = cinfo->max_v_samp_factor * DCTSIZE;
fullsize_width = jround_up(cinfo->image_width,
(long) (cinfo->max_h_samp_factor * DCTSIZE));
/* Prepare for single scan containing all components */
if (cinfo->comps_in_scan == 1) {
noninterleaved_scan_setup(cinfo);
/* Need to read Vk MCU rows to obtain Vk block rows */
mcu_rows_per_loop = cinfo->cur_comp_info[0]->v_samp_factor;
} else {
interleaved_scan_setup(cinfo);
/* in an interleaved scan, one MCU row provides Vk block rows */
mcu_rows_per_loop = 1;
}
cinfo->total_passes++;
/* Allocate working memory: */
/* coeff_data holds a single MCU row of coefficient blocks */
coeff_data = alloc_MCU_row(cinfo);
/* if doing cross-block smoothing, need extra space for its input */
#ifdef BLOCK_SMOOTHING_SUPPORTED
if (cinfo->do_block_smoothing) {
bsmooth[0] = alloc_MCU_row(cinfo);
bsmooth[1] = alloc_MCU_row(cinfo);
bsmooth[2] = alloc_MCU_row(cinfo);
}
#endif
/* subsampled_data is sample data before unsubsampling */
alloc_sampling_buffer(cinfo, subsampled_data);
/* fullsize_data is sample data after unsubsampling */
fullsize_data = alloc_sampimage(cinfo, (int) cinfo->num_components,
(long) rows_in_mem, fullsize_width);
/* output_workspace is the color-processed data */
output_workspace = alloc_sampimage(cinfo, (int) cinfo->final_out_comps,
(long) rows_in_mem, fullsize_width);
/* Tell the memory manager to instantiate big arrays.
* We don't need any big arrays in this controller,
* but some other module (like the output file writer) may need one.
*/
(*cinfo->emethods->alloc_big_arrays)
((long) 0, /* no more small sarrays */
(long) 0, /* no more small barrays */
(long) 0); /* no more "medium" objects */
/* NB: if quantizer needs any "medium" size objects, it must get them */
/* at color_quant_init time */
/* Initialize to read scan data */
(*cinfo->methods->entropy_decoder_init) (cinfo);
(*cinfo->methods->unsubsample_init) (cinfo);
(*cinfo->methods->disassemble_init) (cinfo);
/* Loop over scan's data: rows_in_mem pixel rows are processed per loop */
pixel_rows_output = 0;
whichss = 1; /* arrange to start with subsampled_data[0] */
for (cur_mcu_row = 0; cur_mcu_row < cinfo->MCU_rows_in_scan;
cur_mcu_row += mcu_rows_per_loop) {
(*cinfo->methods->progress_monitor) (cinfo, cur_mcu_row,
cinfo->MCU_rows_in_scan);
whichss ^= 1; /* switch to other subsample buffer */
/* Obtain v_samp_factor block rows of each component in the scan. */
/* This is a single MCU row if interleaved, multiple MCU rows if not. */
/* In the noninterleaved case there might be fewer than v_samp_factor */
/* block rows remaining; if so, pad with copies of the last pixel row */
/* so that unsubsampling doesn't have to treat it as a special case. */
for (ri = 0; ri < mcu_rows_per_loop; ri++) {
if (cur_mcu_row + ri < cinfo->MCU_rows_in_scan) {
/* OK to actually read an MCU row. */
#ifdef BLOCK_SMOOTHING_SUPPORTED
if (cinfo->do_block_smoothing)
get_smoothed_row(cinfo, coeff_data,
bsmooth, &whichb, cur_mcu_row + ri);
else
#endif
(*cinfo->methods->disassemble_MCU) (cinfo, coeff_data);
(*cinfo->methods->reverse_DCT) (cinfo, coeff_data,
subsampled_data[whichss],
ri * DCTSIZE);
} else {
/* Need to pad out with copies of the last subsampled row. */
/* This can only happen if there is just one component. */
duplicate_row(subsampled_data[whichss][0],
cinfo->cur_comp_info[0]->subsampled_width,
ri * DCTSIZE - 1, DCTSIZE);
}
}
/* Unsubsample the data */
/* First time through is a special case */
if (cur_mcu_row) {
/* Expand last row group of previous set */
expand(cinfo, subsampled_data[whichss], fullsize_data, fullsize_width,
(short) DCTSIZE, (short) (DCTSIZE+1), (short) 0,
(short) (DCTSIZE-1));
/* and dump the previous set's expanded data */
emit_1pass (cinfo, rows_in_mem, fullsize_data, NULL);
pixel_rows_output += rows_in_mem;
/* Expand first row group of this set */
expand(cinfo, subsampled_data[whichss], fullsize_data, fullsize_width,
(short) (DCTSIZE+1), (short) 0, (short) 1,
(short) 0);
} else {
/* Expand first row group with dummy above-context */
expand(cinfo, subsampled_data[whichss], fullsize_data, fullsize_width,
(short) (-1), (short) 0, (short) 1,
(short) 0);
}
/* Expand second through next-to-last row groups of this set */
for (i = 1; i <= DCTSIZE-2; i++) {
expand(cinfo, subsampled_data[whichss], fullsize_data, fullsize_width,
(short) (i-1), (short) i, (short) (i+1),
(short) i);
}
} /* end of outer loop */
/* Expand the last row group with dummy below-context */
/* Note whichss points to last buffer side used */
expand(cinfo, subsampled_data[whichss], fullsize_data, fullsize_width,
(short) (DCTSIZE-2), (short) (DCTSIZE-1), (short) (-1),
(short) (DCTSIZE-1));
/* and dump the remaining data (may be less than full height) */
emit_1pass (cinfo, (int) (cinfo->image_height - pixel_rows_output),
fullsize_data, NULL);
/* Clean up after the scan */
(*cinfo->methods->disassemble_term) (cinfo);
(*cinfo->methods->unsubsample_term) (cinfo);
(*cinfo->methods->entropy_decoder_term) (cinfo);
(*cinfo->methods->read_scan_trailer) (cinfo);
cinfo->completed_passes++;
/* Verify that we've seen the whole input file */
if ((*cinfo->methods->read_scan_header) (cinfo))
ERREXIT(cinfo->emethods, "Didn't expect more than one scan");
/* Release working memory */
/* (no work -- we let free_all release what's needful) */
}
/*
* Decompression pipeline controller used for multiple-scan files
* and/or 2-pass color quantization.
*
* The current implementation places the "big" buffer at the stage of
* desubsampled, non-color-processed data. This is the only place that
* makes sense when doing 2-pass quantization. For processing multiple-scan
* files without 2-pass quantization, it would be possible to develop another
* controller that buffers the subsampled data instead, thus reducing the size
* of the temp files (by about a factor of 2 in typical cases). However,
* our present unsubsampling logic is dependent on the assumption that
* unsubsampling occurs during a scan, so it's much easier to do the
* enlargement as the JPEG file is read. This also simplifies life for the
* memory manager, which would otherwise have to deal with overlapping
* access_big_sarray() requests.
* At present it appears that most JPEG files will be single-scan,
* so it doesn't seem worthwhile to worry about this optimization.
*/
#ifdef NEED_COMPLEX_CONTROLLER
METHODDEF void
complex_dcontroller (decompress_info_ptr cinfo)
{
long fullsize_width; /* # of samples per row in full-size buffers */
long cur_mcu_row; /* counts # of MCU rows processed */
long pixel_rows_output; /* # of pixel rows actually emitted */
int mcu_rows_per_loop; /* # of MCU rows processed per outer loop */
/* Work buffer for dequantized coefficients (IDCT input) */
JBLOCKIMAGE coeff_data;
/* Work buffer for cross-block smoothing input */
#ifdef BLOCK_SMOOTHING_SUPPORTED
JBLOCKIMAGE bsmooth[3]; /* this is optional */
int whichb;
#endif
/* Work buffer for subsampled image data (see comments at head of file) */
JSAMPIMAGE subsampled_data[2];
int whichss, ri;
short ci, i;
boolean single_scan;
/* Compute dimensions of full-size pixel buffers */
/* Note these are the same whether interleaved or not. */
rows_in_mem = cinfo->max_v_samp_factor * DCTSIZE;
fullsize_width = jround_up(cinfo->image_width,
(long) (cinfo->max_h_samp_factor * DCTSIZE));
/* Allocate all working memory that doesn't depend on scan info */
/* output_workspace is the color-processed data */
output_workspace = alloc_sampimage(cinfo, (int) cinfo->final_out_comps,
(long) rows_in_mem, fullsize_width);
/* Get a big image: fullsize_image is sample data after unsubsampling. */
fullsize_image = (big_sarray_ptr *) (*cinfo->emethods->alloc_small)
(cinfo->num_components * SIZEOF(big_sarray_ptr));
for (ci = 0; ci < cinfo->num_components; ci++) {
fullsize_image[ci] = (*cinfo->emethods->request_big_sarray)
(fullsize_width,
jround_up(cinfo->image_height, (long) rows_in_mem),
(long) rows_in_mem);
}
/* Also get an area for pointers to currently accessible chunks */
fullsize_ptrs = (JSAMPIMAGE) (*cinfo->emethods->alloc_small)
(cinfo->num_components * SIZEOF(JSAMPARRAY));
/* Tell the memory manager to instantiate big arrays */
(*cinfo->emethods->alloc_big_arrays)
/* extra sarray space is for subsampled-data buffers: */
((long) (fullsize_width /* max width in samples */
* cinfo->max_v_samp_factor*(DCTSIZE+2) /* max height */
* cinfo->num_components), /* max components per scan */
/* extra barray space is for MCU-row buffers: */
(long) ((fullsize_width / DCTSIZE) /* max width in blocks */
* cinfo->max_v_samp_factor /* max height */
* cinfo->num_components /* max components per scan */
* (cinfo->do_block_smoothing ? 4 : 1)),/* how many of these we need */
/* no extra "medium"-object space */
(long) 0);
/* NB: if quantizer needs any "medium" size objects, it must get them */
/* at color_quant_init time */
/* If file is single-scan, we can do color quantization prescan on-the-fly
* during the scan (we must be doing 2-pass quantization, else this method
* would not have been selected). If it is multiple scans, we have to make
* a separate pass after we've collected all the components. (We could save
* some I/O by doing CQ prescan during the last scan, but the extra logic
* doesn't seem worth the trouble.)
*/
single_scan = (cinfo->comps_in_scan == cinfo->num_components);
/* Account for passes needed (color quantizer adds its passes separately).
* If multiscan file, we guess that each component has its own scan,
* and increment completed_passes by the number of components in the scan.
*/
if (single_scan)
cinfo->total_passes++; /* the single scan */
else {
cinfo->total_passes += cinfo->num_components; /* guessed # of scans */
if (cinfo->two_pass_quantize)
cinfo->total_passes++; /* account for separate CQ prescan pass */
}
if (! cinfo->two_pass_quantize)
cinfo->total_passes++; /* count output pass unless quantizer does it */
/* Loop over scans in file */
do {
/* Prepare for this scan */
if (cinfo->comps_in_scan == 1) {
noninterleaved_scan_setup(cinfo);
/* Need to read Vk MCU rows to obtain Vk block rows */
mcu_rows_per_loop = cinfo->cur_comp_info[0]->v_samp_factor;
} else {
interleaved_scan_setup(cinfo);
/* in an interleaved scan, one MCU row provides Vk block rows */
mcu_rows_per_loop = 1;
}
/* Allocate scan-local working memory */
/* coeff_data holds a single MCU row of coefficient blocks */
coeff_data = alloc_MCU_row(cinfo);
/* if doing cross-block smoothing, need extra space for its input */
#ifdef BLOCK_SMOOTHING_SUPPORTED
if (cinfo->do_block_smoothing) {
bsmooth[0] = alloc_MCU_row(cinfo);
bsmooth[1] = alloc_MCU_row(cinfo);
bsmooth[2] = alloc_MCU_row(cinfo);
}
#endif
/* subsampled_data is sample data before unsubsampling */
alloc_sampling_buffer(cinfo, subsampled_data);
/* line up the big buffers for components in this scan */
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
fullsize_ptrs[ci] = (*cinfo->emethods->access_big_sarray)
(fullsize_image[cinfo->cur_comp_info[ci]->component_index],
(long) 0, TRUE);
}
/* Initialize to read scan data */
(*cinfo->methods->entropy_decoder_init) (cinfo);
(*cinfo->methods->unsubsample_init) (cinfo);
(*cinfo->methods->disassemble_init) (cinfo);
/* Loop over scan's data: rows_in_mem pixel rows are processed per loop */
pixel_rows_output = 0;
whichss = 1; /* arrange to start with subsampled_data[0] */
for (cur_mcu_row = 0; cur_mcu_row < cinfo->MCU_rows_in_scan;
cur_mcu_row += mcu_rows_per_loop) {
(*cinfo->methods->progress_monitor) (cinfo, cur_mcu_row,
cinfo->MCU_rows_in_scan);
whichss ^= 1; /* switch to other subsample buffer */
/* Obtain v_samp_factor block rows of each component in the scan. */
/* This is a single MCU row if interleaved, multiple MCU rows if not. */
/* In the noninterleaved case there might be fewer than v_samp_factor */
/* block rows remaining; if so, pad with copies of the last pixel row */
/* so that unsubsampling doesn't have to treat it as a special case. */
for (ri = 0; ri < mcu_rows_per_loop; ri++) {
if (cur_mcu_row + ri < cinfo->MCU_rows_in_scan) {
/* OK to actually read an MCU row. */
#ifdef BLOCK_SMOOTHING_SUPPORTED
if (cinfo->do_block_smoothing)
get_smoothed_row(cinfo, coeff_data,
bsmooth, &whichb, cur_mcu_row + ri);
else
#endif
(*cinfo->methods->disassemble_MCU) (cinfo, coeff_data);
(*cinfo->methods->reverse_DCT) (cinfo, coeff_data,
subsampled_data[whichss],
ri * DCTSIZE);
} else {
/* Need to pad out with copies of the last subsampled row. */
/* This can only happen if there is just one component. */
duplicate_row(subsampled_data[whichss][0],
cinfo->cur_comp_info[0]->subsampled_width,
ri * DCTSIZE - 1, DCTSIZE);
}
}
/* Unsubsample the data */
/* First time through is a special case */
if (cur_mcu_row) {
/* Expand last row group of previous set */
expand(cinfo, subsampled_data[whichss], fullsize_ptrs, fullsize_width,
(short) DCTSIZE, (short) (DCTSIZE+1), (short) 0,
(short) (DCTSIZE-1));
/* If single scan, can do color quantization prescan on-the-fly */
if (single_scan)
(*cinfo->methods->color_quant_prescan) (cinfo, rows_in_mem,
fullsize_ptrs,
output_workspace[0]);
/* Realign the big buffers */
pixel_rows_output += rows_in_mem;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
fullsize_ptrs[ci] = (*cinfo->emethods->access_big_sarray)
(fullsize_image[cinfo->cur_comp_info[ci]->component_index],
pixel_rows_output, TRUE);
}
/* Expand first row group of this set */
expand(cinfo, subsampled_data[whichss], fullsize_ptrs, fullsize_width,
(short) (DCTSIZE+1), (short) 0, (short) 1,
(short) 0);
} else {
/* Expand first row group with dummy above-context */
expand(cinfo, subsampled_data[whichss], fullsize_ptrs, fullsize_width,
(short) (-1), (short) 0, (short) 1,
(short) 0);
}
/* Expand second through next-to-last row groups of this set */
for (i = 1; i <= DCTSIZE-2; i++) {
expand(cinfo, subsampled_data[whichss], fullsize_ptrs, fullsize_width,
(short) (i-1), (short) i, (short) (i+1),
(short) i);
}
} /* end of loop over scan's data */
/* Expand the last row group with dummy below-context */
/* Note whichss points to last buffer side used */
expand(cinfo, subsampled_data[whichss], fullsize_ptrs, fullsize_width,
(short) (DCTSIZE-2), (short) (DCTSIZE-1), (short) (-1),
(short) (DCTSIZE-1));
/* If single scan, finish on-the-fly color quantization prescan */
if (single_scan)
(*cinfo->methods->color_quant_prescan) (cinfo,
(int) (cinfo->image_height - pixel_rows_output),
fullsize_ptrs, output_workspace[0]);
/* Clean up after the scan */
(*cinfo->methods->disassemble_term) (cinfo);
(*cinfo->methods->unsubsample_term) (cinfo);
(*cinfo->methods->entropy_decoder_term) (cinfo);
(*cinfo->methods->read_scan_trailer) (cinfo);
if (single_scan)
cinfo->completed_passes++;
else
cinfo->completed_passes += cinfo->comps_in_scan;
/* Release scan-local working memory */
free_MCU_row(cinfo, coeff_data);
#ifdef BLOCK_SMOOTHING_SUPPORTED
if (cinfo->do_block_smoothing) {
free_MCU_row(cinfo, bsmooth[0]);
free_MCU_row(cinfo, bsmooth[1]);
free_MCU_row(cinfo, bsmooth[2]);
}
#endif
free_sampling_buffer(cinfo, subsampled_data);
/* Repeat if there is another scan */
} while ((!single_scan) && (*cinfo->methods->read_scan_header) (cinfo));
if (single_scan) {
/* If we expected just one scan, make SURE there's just one */
if ((*cinfo->methods->read_scan_header) (cinfo))
ERREXIT(cinfo->emethods, "Didn't expect more than one scan");
/* We did the CQ prescan on-the-fly, so we are all set. */
} else {
/* For multiple-scan file, do the CQ prescan as a separate pass. */
/* The main reason why prescan is passed the output_workspace is */
/* so that we can use scan_big_image to call it... */
if (cinfo->two_pass_quantize)
scan_big_image(cinfo, cinfo->methods->color_quant_prescan);
}
/* Now that we've collected the data, do color processing and output */
if (cinfo->two_pass_quantize)
(*cinfo->methods->color_quant_doit) (cinfo, scan_big_image);
else
scan_big_image(cinfo, emit_1pass);
/* Release working memory */
/* (no work -- we let free_all release what's needful) */
}
#endif /* NEED_COMPLEX_CONTROLLER */
/*
* The method selection routine for decompression pipeline controllers.
* Note that at this point we've already read the JPEG header and first SOS,
* so we can tell whether the input is one scan or not.
*/
GLOBAL void
jseldpipeline (decompress_info_ptr cinfo)
{
/* simplify subsequent tests on color quantization */
if (! cinfo->quantize_colors)
cinfo->two_pass_quantize = FALSE;
if (cinfo->comps_in_scan == cinfo->num_components) {
/* It's a single-scan file */
if (cinfo->two_pass_quantize) {
#ifdef NEED_COMPLEX_CONTROLLER
cinfo->methods->d_pipeline_controller = complex_dcontroller;
#else
ERREXIT(cinfo->emethods, "2-pass quantization support was not compiled");
#endif
} else
cinfo->methods->d_pipeline_controller = simple_dcontroller;
} else {
/* It's a multiple-scan file */
#ifdef NEED_COMPLEX_CONTROLLER
cinfo->methods->d_pipeline_controller = complex_dcontroller;
#else
ERREXIT(cinfo->emethods, "Multiple-scan support was not compiled");
#endif
}
}
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