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10fdbde7bf
libjpeg-turbo/jcmaster.c
Vadim Zeitlin 10fdbde7bf The Independent JPEG Group's JPEG software v9c 
Import libjpeg 9c from https://www.ijg.org/files/jpegsrc.v9c.tar.gz
2020-04-04 00:29:08 +02:00

675 lines
22 KiB
C
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/*
* jcmaster.c
*
* Copyright (C) 1991-1997, Thomas G. Lane.
* Modified 2003-2017 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 master control logic for the JPEG compressor.
* These routines are concerned with parameter validation, initial setup,
* and inter-pass control (determining the number of passes and the work
* to be done in each pass).
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/* Private state */
typedef enum {
main_pass, /* input data, also do first output step */
huff_opt_pass, /* Huffman code optimization pass */
output_pass /* data output pass */
} c_pass_type;
typedef struct {
struct jpeg_comp_master pub; /* public fields */
c_pass_type pass_type; /* the type of the current pass */
int pass_number; /* # of passes completed */
int total_passes; /* total # of passes needed */
int scan_number; /* current index in scan_info[] */
} my_comp_master;
typedef my_comp_master * my_master_ptr;
/*
* Support routines that do various essential calculations.
*/
LOCAL(void)
initial_setup (j_compress_ptr cinfo)
/* Do computations that are needed before master selection phase */
{
int ci, ssize;
jpeg_component_info *compptr;
/* Sanity check on block_size */
if (cinfo->block_size < 1 || cinfo->block_size > 16)
ERREXIT2(cinfo, JERR_BAD_DCTSIZE, cinfo->block_size, cinfo->block_size);
/* Derive natural_order from block_size */
switch (cinfo->block_size) {
case 2: cinfo->natural_order = jpeg_natural_order2; break;
case 3: cinfo->natural_order = jpeg_natural_order3; break;
case 4: cinfo->natural_order = jpeg_natural_order4; break;
case 5: cinfo->natural_order = jpeg_natural_order5; break;
case 6: cinfo->natural_order = jpeg_natural_order6; break;
case 7: cinfo->natural_order = jpeg_natural_order7; break;
default: cinfo->natural_order = jpeg_natural_order; break;
}
/* Derive lim_Se from block_size */
cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
/* Sanity check on image dimensions */
if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
cinfo->num_components <= 0)
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
/* Make sure image isn't bigger than I can handle */
if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
(long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
/* Only 8 to 12 bits data precision are supported for DCT based JPEG */
if (cinfo->data_precision < 8 || cinfo->data_precision > 12)
ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
/* Check that number of components won't exceed internal array sizes */
if (cinfo->num_components > MAX_COMPONENTS)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
MAX_COMPONENTS);
/* Compute maximum sampling factors; check factor validity */
cinfo->max_h_samp_factor = 1;
cinfo->max_v_samp_factor = 1;
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
ERREXIT(cinfo, JERR_BAD_SAMPLING);
cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
compptr->h_samp_factor);
cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
compptr->v_samp_factor);
}
/* Compute dimensions of components */
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
ci++, compptr++) {
/* Fill in the correct component_index value; don't rely on application */
compptr->component_index = ci;
/* In selecting the actual DCT scaling for each component, we try to
* scale down the chroma components via DCT scaling rather than downsampling.
* This saves time if the downsampler gets to use 1:1 scaling.
* Note this code adapts subsampling ratios which are powers of 2.
*/
ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
while (cinfo->min_DCT_h_scaled_size * ssize <=
(cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
(cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
ssize = ssize * 2;
}
#endif
compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
ssize = 1;
#ifdef DCT_SCALING_SUPPORTED
while (cinfo->min_DCT_v_scaled_size * ssize <=
(cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
(cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
ssize = ssize * 2;
}
#endif
compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
/* We don't support DCT ratios larger than 2. */
if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
/* Size in DCT blocks */
compptr->width_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
(long) (cinfo->max_h_samp_factor * cinfo->block_size));
compptr->height_in_blocks = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
/* Size in samples */
compptr->downsampled_width = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_width *
(long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
(long) (cinfo->max_h_samp_factor * cinfo->block_size));
compptr->downsampled_height = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height *
(long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
/* Don't need quantization scale after DCT,
* until color conversion says otherwise.
*/
compptr->component_needed = FALSE;
}
/* Compute number of fully interleaved MCU rows (number of times that
* main controller will call coefficient controller).
*/
cinfo->total_iMCU_rows = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height,
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
}
#ifdef C_MULTISCAN_FILES_SUPPORTED
LOCAL(void)
validate_script (j_compress_ptr cinfo)
/* Verify that the scan script in cinfo->scan_info[] is valid; also
* determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
*/
{
const jpeg_scan_info * scanptr;
int scanno, ncomps, ci, coefi, thisi;
int Ss, Se, Ah, Al;
boolean component_sent[MAX_COMPONENTS];
#ifdef C_PROGRESSIVE_SUPPORTED
int * last_bitpos_ptr;
int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
/* -1 until that coefficient has been seen; then last Al for it */
#endif
if (cinfo->num_scans <= 0)
ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
/* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
* for progressive JPEG, no scan can have this.
*/
scanptr = cinfo->scan_info;
if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
#ifdef C_PROGRESSIVE_SUPPORTED
cinfo->progressive_mode = TRUE;
last_bitpos_ptr = & last_bitpos[0][0];
for (ci = 0; ci < cinfo->num_components; ci++)
for (coefi = 0; coefi < DCTSIZE2; coefi++)
*last_bitpos_ptr++ = -1;
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
} else {
cinfo->progressive_mode = FALSE;
for (ci = 0; ci < cinfo->num_components; ci++)
component_sent[ci] = FALSE;
}
for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
/* Validate component indexes */
ncomps = scanptr->comps_in_scan;
if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
for (ci = 0; ci < ncomps; ci++) {
thisi = scanptr->component_index[ci];
if (thisi < 0 || thisi >= cinfo->num_components)
ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
/* Components must appear in SOF order within each scan */
if (ci > 0 && thisi <= scanptr->component_index[ci-1])
ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
}
/* Validate progression parameters */
Ss = scanptr->Ss;
Se = scanptr->Se;
Ah = scanptr->Ah;
Al = scanptr->Al;
if (cinfo->progressive_mode) {
#ifdef C_PROGRESSIVE_SUPPORTED
/* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
* seems wrong: the upper bound ought to depend on data precision.
* Perhaps they really meant 0..N+1 for N-bit precision.
* Here we allow 0..10 for 8-bit data; Al larger than 10 results in
* out-of-range reconstructed DC values during the first DC scan,
* which might cause problems for some decoders.
*/
if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
Ah < 0 || Ah > (cinfo->data_precision > 8 ? 13 : 10) ||
Al < 0 || Al > (cinfo->data_precision > 8 ? 13 : 10))
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
if (Ss == 0) {
if (Se != 0) /* DC and AC together not OK */
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
} else {
if (ncomps != 1) /* AC scans must be for only one component */
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
}
for (ci = 0; ci < ncomps; ci++) {
last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
for (coefi = Ss; coefi <= Se; coefi++) {
if (last_bitpos_ptr[coefi] < 0) {
/* first scan of this coefficient */
if (Ah != 0)
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
} else {
/* not first scan */
if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
}
last_bitpos_ptr[coefi] = Al;
}
}
#endif
} else {
/* For sequential JPEG, all progression parameters must be these: */
if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
/* Make sure components are not sent twice */
for (ci = 0; ci < ncomps; ci++) {
thisi = scanptr->component_index[ci];
if (component_sent[thisi])
ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
component_sent[thisi] = TRUE;
}
}
}
/* Now verify that everything got sent. */
if (cinfo->progressive_mode) {
#ifdef C_PROGRESSIVE_SUPPORTED
/* For progressive mode, we only check that at least some DC data
* got sent for each component; the spec does not require that all bits
* of all coefficients be transmitted. Would it be wiser to enforce
* transmission of all coefficient bits??
*/
for (ci = 0; ci < cinfo->num_components; ci++) {
if (last_bitpos[ci][0] < 0)
ERREXIT(cinfo, JERR_MISSING_DATA);
}
#endif
} else {
for (ci = 0; ci < cinfo->num_components; ci++) {
if (! component_sent[ci])
ERREXIT(cinfo, JERR_MISSING_DATA);
}
}
}
LOCAL(void)
reduce_script (j_compress_ptr cinfo)
/* Adapt scan script for use with reduced block size;
* assume that script has been validated before.
*/
{
jpeg_scan_info * scanptr;
int idxout, idxin;
/* Circumvent const declaration for this function */
scanptr = (jpeg_scan_info *) cinfo->scan_info;
idxout = 0;
for (idxin = 0; idxin < cinfo->num_scans; idxin++) {
/* After skipping, idxout becomes smaller than idxin */
if (idxin != idxout)
/* Copy rest of data;
* note we stay in given chunk of allocated memory.
*/
scanptr[idxout] = scanptr[idxin];
if (scanptr[idxout].Ss > cinfo->lim_Se)
/* Entire scan out of range - skip this entry */
continue;
if (scanptr[idxout].Se > cinfo->lim_Se)
/* Limit scan to end of block */
scanptr[idxout].Se = cinfo->lim_Se;
idxout++;
}
cinfo->num_scans = idxout;
}
#endif /* C_MULTISCAN_FILES_SUPPORTED */
LOCAL(void)
select_scan_parameters (j_compress_ptr cinfo)
/* Set up the scan parameters for the current scan */
{
int ci;
#ifdef C_MULTISCAN_FILES_SUPPORTED
if (cinfo->scan_info != NULL) {
/* Prepare for current scan --- the script is already validated */
my_master_ptr master = (my_master_ptr) cinfo->master;
const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
cinfo->comps_in_scan = scanptr->comps_in_scan;
for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
cinfo->cur_comp_info[ci] =
&cinfo->comp_info[scanptr->component_index[ci]];
}
if (cinfo->progressive_mode) {
cinfo->Ss = scanptr->Ss;
cinfo->Se = scanptr->Se;
cinfo->Ah = scanptr->Ah;
cinfo->Al = scanptr->Al;
return;
}
}
else
#endif
{
/* Prepare for single sequential-JPEG scan containing all components */
if (cinfo->num_components > MAX_COMPS_IN_SCAN)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
MAX_COMPS_IN_SCAN);
cinfo->comps_in_scan = cinfo->num_components;
for (ci = 0; ci < cinfo->num_components; ci++) {
cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
}
}
cinfo->Ss = 0;
cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
cinfo->Ah = 0;
cinfo->Al = 0;
}
LOCAL(void)
per_scan_setup (j_compress_ptr cinfo)
/* Do computations that are needed before processing a JPEG scan */
/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
{
int ci, mcublks, tmp;
jpeg_component_info *compptr;
if (cinfo->comps_in_scan == 1) {
/* Noninterleaved (single-component) scan */
compptr = cinfo->cur_comp_info[0];
/* Overall image size in MCUs */
cinfo->MCUs_per_row = compptr->width_in_blocks;
cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
/* For noninterleaved scan, always one block per MCU */
compptr->MCU_width = 1;
compptr->MCU_height = 1;
compptr->MCU_blocks = 1;
compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
compptr->last_col_width = 1;
/* For noninterleaved scans, it is convenient to define last_row_height
* as the number of block rows present in the last iMCU row.
*/
tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
if (tmp == 0) tmp = compptr->v_samp_factor;
compptr->last_row_height = tmp;
/* Prepare array describing MCU composition */
cinfo->blocks_in_MCU = 1;
cinfo->MCU_membership[0] = 0;
} else {
/* Interleaved (multi-component) scan */
if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
MAX_COMPS_IN_SCAN);
/* Overall image size in MCUs */
cinfo->MCUs_per_row = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_width,
(long) (cinfo->max_h_samp_factor * cinfo->block_size));
cinfo->MCU_rows_in_scan = (JDIMENSION)
jdiv_round_up((long) cinfo->jpeg_height,
(long) (cinfo->max_v_samp_factor * cinfo->block_size));
cinfo->blocks_in_MCU = 0;
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* Sampling factors give # of blocks of component in each MCU */
compptr->MCU_width = compptr->h_samp_factor;
compptr->MCU_height = compptr->v_samp_factor;
compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
/* Figure number of non-dummy blocks in last MCU column & row */
tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
if (tmp == 0) tmp = compptr->MCU_width;
compptr->last_col_width = tmp;
tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
if (tmp == 0) tmp = compptr->MCU_height;
compptr->last_row_height = tmp;
/* Prepare array describing MCU composition */
mcublks = compptr->MCU_blocks;
if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
while (mcublks-- > 0) {
cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
}
}
}
/* Convert restart specified in rows to actual MCU count. */
/* Note that count must fit in 16 bits, so we provide limiting. */
if (cinfo->restart_in_rows > 0) {
long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
}
}
/*
* Per-pass setup.
* This is called at the beginning of each pass. We determine which modules
* will be active during this pass and give them appropriate start_pass calls.
* We also set is_last_pass to indicate whether any more passes will be
* required.
*/
METHODDEF(void)
prepare_for_pass (j_compress_ptr cinfo)
{
my_master_ptr master = (my_master_ptr) cinfo->master;
switch (master->pass_type) {
case main_pass:
/* Initial pass: will collect input data, and do either Huffman
* optimization or data output for the first scan.
*/
select_scan_parameters(cinfo);
per_scan_setup(cinfo);
if (! cinfo->raw_data_in) {
(*cinfo->cconvert->start_pass) (cinfo);
(*cinfo->downsample->start_pass) (cinfo);
(*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
}
(*cinfo->fdct->start_pass) (cinfo);
(*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
(*cinfo->coef->start_pass) (cinfo,
(master->total_passes > 1 ?
JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
(*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
if (cinfo->optimize_coding) {
/* No immediate data output; postpone writing frame/scan headers */
master->pub.call_pass_startup = FALSE;
} else {
/* Will write frame/scan headers at first jpeg_write_scanlines call */
master->pub.call_pass_startup = TRUE;
}
break;
#ifdef ENTROPY_OPT_SUPPORTED
case huff_opt_pass:
/* Do Huffman optimization for a scan after the first one. */
select_scan_parameters(cinfo);
per_scan_setup(cinfo);
if (cinfo->Ss != 0 || cinfo->Ah == 0) {
(*cinfo->entropy->start_pass) (cinfo, TRUE);
(*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
master->pub.call_pass_startup = FALSE;
break;
}
/* Special case: Huffman DC refinement scans need no Huffman table
* and therefore we can skip the optimization pass for them.
*/
master->pass_type = output_pass;
master->pass_number++;
/*FALLTHROUGH*/
#endif
case output_pass:
/* Do a data-output pass. */
/* We need not repeat per-scan setup if prior optimization pass did it. */
if (! cinfo->optimize_coding) {
select_scan_parameters(cinfo);
per_scan_setup(cinfo);
}
(*cinfo->entropy->start_pass) (cinfo, FALSE);
(*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
/* We emit frame/scan headers now */
if (master->scan_number == 0)
(*cinfo->marker->write_frame_header) (cinfo);
(*cinfo->marker->write_scan_header) (cinfo);
master->pub.call_pass_startup = FALSE;
break;
default:
ERREXIT(cinfo, JERR_NOT_COMPILED);
}
master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
/* Set up progress monitor's pass info if present */
if (cinfo->progress != NULL) {
cinfo->progress->completed_passes = master->pass_number;
cinfo->progress->total_passes = master->total_passes;
}
}
/*
* Special start-of-pass hook.
* This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
* In single-pass processing, we need this hook because we don't want to
* write frame/scan headers during jpeg_start_compress; we want to let the
* application write COM markers etc. between jpeg_start_compress and the
* jpeg_write_scanlines loop.
* In multi-pass processing, this routine is not used.
*/
METHODDEF(void)
pass_startup (j_compress_ptr cinfo)
{
cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
(*cinfo->marker->write_frame_header) (cinfo);
(*cinfo->marker->write_scan_header) (cinfo);
}
/*
* Finish up at end of pass.
*/
METHODDEF(void)
finish_pass_master (j_compress_ptr cinfo)
{
my_master_ptr master = (my_master_ptr) cinfo->master;
/* The entropy coder always needs an end-of-pass call,
* either to analyze statistics or to flush its output buffer.
*/
(*cinfo->entropy->finish_pass) (cinfo);
/* Update state for next pass */
switch (master->pass_type) {
case main_pass:
/* next pass is either output of scan 0 (after optimization)
* or output of scan 1 (if no optimization).
*/
master->pass_type = output_pass;
if (! cinfo->optimize_coding)
master->scan_number++;
break;
case huff_opt_pass:
/* next pass is always output of current scan */
master->pass_type = output_pass;
break;
case output_pass:
/* next pass is either optimization or output of next scan */
if (cinfo->optimize_coding)
master->pass_type = huff_opt_pass;
master->scan_number++;
break;
}
master->pass_number++;
}
/*
* Initialize master compression control.
*/
GLOBAL(void)
jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
{
my_master_ptr master;
master = (my_master_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(my_comp_master));
cinfo->master = &master->pub;
master->pub.prepare_for_pass = prepare_for_pass;
master->pub.pass_startup = pass_startup;
master->pub.finish_pass = finish_pass_master;
master->pub.is_last_pass = FALSE;
/* Validate parameters, determine derived values */
initial_setup(cinfo);
if (cinfo->scan_info != NULL) {
#ifdef C_MULTISCAN_FILES_SUPPORTED
validate_script(cinfo);
if (cinfo->block_size < DCTSIZE)
reduce_script(cinfo);
#else
ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
} else {
cinfo->progressive_mode = FALSE;
cinfo->num_scans = 1;
}
if (cinfo->optimize_coding)
cinfo->arith_code = FALSE; /* disable arithmetic coding */
else if (! cinfo->arith_code &&
(cinfo->progressive_mode ||
(cinfo->block_size > 1 && cinfo->block_size < DCTSIZE)))
/* TEMPORARY HACK ??? */
/* assume default tables no good for progressive or reduced AC mode */
cinfo->optimize_coding = TRUE; /* force Huffman optimization */
/* Initialize my private state */
if (transcode_only) {
/* no main pass in transcoding */
if (cinfo->optimize_coding)
master->pass_type = huff_opt_pass;
else
master->pass_type = output_pass;
} else {
/* for normal compression, first pass is always this type: */
master->pass_type = main_pass;
}
master->scan_number = 0;
master->pass_number = 0;
if (cinfo->optimize_coding)
master->total_passes = cinfo->num_scans * 2;
else
master->total_passes = cinfo->num_scans;
}
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