#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* jdmaster.c | |
* | |
* Copyright (C) 1991-1997, 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 master control logic for the JPEG decompressor. | |
* These routines are concerned with selecting the modules to be executed | |
* and with 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 struct { | |
struct jpeg_decomp_master pub; /* public fields */ | |
int pass_number; /* # of passes completed */ | |
boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */ | |
/* Saved references to initialized quantizer modules, | |
* in case we need to switch modes. | |
*/ | |
struct jpeg_color_quantizer * quantizer_1pass; | |
struct jpeg_color_quantizer * quantizer_2pass; | |
} my_decomp_master; | |
typedef my_decomp_master * my_master_ptr; | |
/* | |
* Determine whether merged upsample/color conversion should be used. | |
* CRUCIAL: this must match the actual capabilities of jdmerge.c! | |
*/ | |
LOCAL(boolean) | |
use_merged_upsample (j_decompress_ptr cinfo) | |
{ | |
#ifdef UPSAMPLE_MERGING_SUPPORTED | |
/* Merging is the equivalent of plain box-filter upsampling */ | |
if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) | |
return FALSE; | |
/* jdmerge.c only supports YCC=>RGB color conversion */ | |
if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 || | |
cinfo->out_color_space != JCS_RGB || | |
cinfo->out_color_components != RGB_PIXELSIZE) | |
return FALSE; | |
/* and it only handles 2h1v or 2h2v sampling ratios */ | |
if (cinfo->comp_info[0].h_samp_factor != 2 || | |
cinfo->comp_info[1].h_samp_factor != 1 || | |
cinfo->comp_info[2].h_samp_factor != 1 || | |
cinfo->comp_info[0].v_samp_factor > 2 || | |
cinfo->comp_info[1].v_samp_factor != 1 || | |
cinfo->comp_info[2].v_samp_factor != 1) | |
return FALSE; | |
/* furthermore, it doesn't work if we've scaled the IDCTs differently */ | |
if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size || | |
cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size || | |
cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size) | |
return FALSE; | |
/* ??? also need to test for upsample-time rescaling, when & if supported */ | |
return TRUE; /* by golly, it'll work... */ | |
#else | |
return FALSE; | |
#endif | |
} | |
/* | |
* Compute output image dimensions and related values. | |
* NOTE: this is exported for possible use by application. | |
* Hence it mustn't do anything that can't be done twice. | |
* Also note that it may be called before the master module is initialized! | |
*/ | |
GLOBAL(void) | |
jpeg_calc_output_dimensions (j_decompress_ptr cinfo) | |
/* Do computations that are needed before master selection phase */ | |
{ | |
#ifdef IDCT_SCALING_SUPPORTED | |
int ci; | |
jpeg_component_info *compptr; | |
#endif | |
/* Prevent application from calling me at wrong times */ | |
if (cinfo->global_state != DSTATE_READY) | |
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
#ifdef IDCT_SCALING_SUPPORTED | |
/* Compute actual output image dimensions and DCT scaling choices. */ | |
if (cinfo->scale_num * 8 <= cinfo->scale_denom) { | |
/* Provide 1/8 scaling */ | |
cinfo->output_width = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_width, 8L); | |
cinfo->output_height = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_height, 8L); | |
cinfo->min_DCT_scaled_size = 1; | |
} else if (cinfo->scale_num * 4 <= cinfo->scale_denom) { | |
/* Provide 1/4 scaling */ | |
cinfo->output_width = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_width, 4L); | |
cinfo->output_height = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_height, 4L); | |
cinfo->min_DCT_scaled_size = 2; | |
} else if (cinfo->scale_num * 2 <= cinfo->scale_denom) { | |
/* Provide 1/2 scaling */ | |
cinfo->output_width = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_width, 2L); | |
cinfo->output_height = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_height, 2L); | |
cinfo->min_DCT_scaled_size = 4; | |
} else { | |
/* Provide 1/1 scaling */ | |
cinfo->output_width = cinfo->image_width; | |
cinfo->output_height = cinfo->image_height; | |
cinfo->min_DCT_scaled_size = DCTSIZE; | |
} | |
/* In selecting the actual DCT scaling for each component, we try to | |
* scale up the chroma components via IDCT scaling rather than upsampling. | |
* This saves time if the upsampler gets to use 1:1 scaling. | |
* Note this code assumes that the supported DCT scalings are powers of 2. | |
*/ | |
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
ci++, compptr++) { | |
int ssize = cinfo->min_DCT_scaled_size; | |
while (ssize < DCTSIZE && | |
(compptr->h_samp_factor * ssize * 2 <= | |
cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) && | |
(compptr->v_samp_factor * ssize * 2 <= | |
cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size)) { | |
ssize = ssize * 2; | |
} | |
compptr->DCT_scaled_size = ssize; | |
} | |
/* Recompute downsampled dimensions of components; | |
* application needs to know these if using raw downsampled data. | |
*/ | |
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
ci++, compptr++) { | |
/* Size in samples, after IDCT scaling */ | |
compptr->downsampled_width = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_width * | |
(long) (compptr->h_samp_factor * compptr->DCT_scaled_size), | |
(long) (cinfo->max_h_samp_factor * DCTSIZE)); | |
compptr->downsampled_height = (JDIMENSION) | |
jdiv_round_up((long) cinfo->image_height * | |
(long) (compptr->v_samp_factor * compptr->DCT_scaled_size), | |
(long) (cinfo->max_v_samp_factor * DCTSIZE)); | |
} | |
#else /* !IDCT_SCALING_SUPPORTED */ | |
/* Hardwire it to "no scaling" */ | |
cinfo->output_width = cinfo->image_width; | |
cinfo->output_height = cinfo->image_height; | |
/* jdinput.c has already initialized DCT_scaled_size to DCTSIZE, | |
* and has computed unscaled downsampled_width and downsampled_height. | |
*/ | |
#endif /* IDCT_SCALING_SUPPORTED */ | |
/* Report number of components in selected colorspace. */ | |
/* Probably this should be in the color conversion module... */ | |
switch (cinfo->out_color_space) { | |
case JCS_GRAYSCALE: | |
cinfo->out_color_components = 1; | |
break; | |
case JCS_RGB: | |
#if RGB_PIXELSIZE != 3 | |
cinfo->out_color_components = RGB_PIXELSIZE; | |
break; | |
#endif /* else share code with YCbCr */ | |
case JCS_YCbCr: | |
cinfo->out_color_components = 3; | |
break; | |
case JCS_CMYK: | |
case JCS_YCCK: | |
cinfo->out_color_components = 4; | |
break; | |
default: /* else must be same colorspace as in file */ | |
cinfo->out_color_components = cinfo->num_components; | |
break; | |
} | |
cinfo->output_components = (cinfo->quantize_colors ? 1 : | |
cinfo->out_color_components); | |
/* See if upsampler will want to emit more than one row at a time */ | |
if (use_merged_upsample(cinfo)) | |
cinfo->rec_outbuf_height = cinfo->max_v_samp_factor; | |
else | |
cinfo->rec_outbuf_height = 1; | |
} | |
/* | |
* Several decompression processes need to range-limit values to the range | |
* 0..MAXJSAMPLE; the input value may fall somewhat outside this range | |
* due to noise introduced by quantization, roundoff error, etc. These | |
* processes are inner loops and need to be as fast as possible. On most | |
* machines, particularly CPUs with pipelines or instruction prefetch, | |
* a (subscript-check-less) C table lookup | |
* x = sample_range_limit[x]; | |
* is faster than explicit tests | |
* if (x < 0) x = 0; | |
* else if (x > MAXJSAMPLE) x = MAXJSAMPLE; | |
* These processes all use a common table prepared by the routine below. | |
* | |
* For most steps we can mathematically guarantee that the initial value | |
* of x is within MAXJSAMPLE+1 of the legal range, so a table running from | |
* -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial | |
* limiting step (just after the IDCT), a wildly out-of-range value is | |
* possible if the input data is corrupt. To avoid any chance of indexing | |
* off the end of memory and getting a bad-pointer trap, we perform the | |
* post-IDCT limiting thus: | |
* x = range_limit[x & MASK]; | |
* where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit | |
* samples. Under normal circumstances this is more than enough range and | |
* a correct output will be generated; with bogus input data the mask will | |
* cause wraparound, and we will safely generate a bogus-but-in-range output. | |
* For the post-IDCT step, we want to convert the data from signed to unsigned | |
* representation by adding CENTERJSAMPLE at the same time that we limit it. | |
* So the post-IDCT limiting table ends up looking like this: | |
* CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE, | |
* MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), | |
* 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), | |
* 0,1,...,CENTERJSAMPLE-1 | |
* Negative inputs select values from the upper half of the table after | |
* masking. | |
* | |
* We can save some space by overlapping the start of the post-IDCT table | |
* with the simpler range limiting table. The post-IDCT table begins at | |
* sample_range_limit + CENTERJSAMPLE. | |
* | |
* Note that the table is allocated in near data space on PCs; it's small | |
* enough and used often enough to justify this. | |
*/ | |
LOCAL(void) | |
prepare_range_limit_table (j_decompress_ptr cinfo) | |
/* Allocate and fill in the sample_range_limit table */ | |
{ | |
JSAMPLE * table; | |
int i; | |
table = (JSAMPLE *) | |
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
(5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE)); | |
table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */ | |
cinfo->sample_range_limit = table; | |
/* First segment of "simple" table: limit[x] = 0 for x < 0 */ | |
MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE)); | |
/* Main part of "simple" table: limit[x] = x */ | |
for (i = 0; i <= MAXJSAMPLE; i++) | |
table[i] = (JSAMPLE) i; | |
table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */ | |
/* End of simple table, rest of first half of post-IDCT table */ | |
for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++) | |
table[i] = MAXJSAMPLE; | |
/* Second half of post-IDCT table */ | |
MEMZERO(table + (2 * (MAXJSAMPLE+1)), | |
(2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE)); | |
MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE), | |
cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE)); | |
} | |
/* | |
* Master selection of decompression modules. | |
* This is done once at jpeg_start_decompress time. We determine | |
* which modules will be used and give them appropriate initialization calls. | |
* We also initialize the decompressor input side to begin consuming data. | |
* | |
* Since jpeg_read_header has finished, we know what is in the SOF | |
* and (first) SOS markers. We also have all the application parameter | |
* settings. | |
*/ | |
LOCAL(void) | |
master_selection (j_decompress_ptr cinfo) | |
{ | |
my_master_ptr master = (my_master_ptr) cinfo->master; | |
boolean use_c_buffer; | |
long samplesperrow; | |
JDIMENSION jd_samplesperrow; | |
/* Initialize dimensions and other stuff */ | |
jpeg_calc_output_dimensions(cinfo); | |
prepare_range_limit_table(cinfo); | |
/* Width of an output scanline must be representable as JDIMENSION. */ | |
samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components; | |
jd_samplesperrow = (JDIMENSION) samplesperrow; | |
if ((long) jd_samplesperrow != samplesperrow) | |
ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); | |
/* Initialize my private state */ | |
master->pass_number = 0; | |
master->using_merged_upsample = use_merged_upsample(cinfo); | |
/* Color quantizer selection */ | |
master->quantizer_1pass = NULL; | |
master->quantizer_2pass = NULL; | |
/* No mode changes if not using buffered-image mode. */ | |
if (! cinfo->quantize_colors || ! cinfo->buffered_image) { | |
cinfo->enable_1pass_quant = FALSE; | |
cinfo->enable_external_quant = FALSE; | |
cinfo->enable_2pass_quant = FALSE; | |
} | |
if (cinfo->quantize_colors) { | |
if (cinfo->raw_data_out) | |
ERREXIT(cinfo, JERR_NOTIMPL); | |
/* 2-pass quantizer only works in 3-component color space. */ | |
if (cinfo->out_color_components != 3) { | |
cinfo->enable_1pass_quant = TRUE; | |
cinfo->enable_external_quant = FALSE; | |
cinfo->enable_2pass_quant = FALSE; | |
cinfo->colormap = NULL; | |
} else if (cinfo->colormap != NULL) { | |
cinfo->enable_external_quant = TRUE; | |
} else if (cinfo->two_pass_quantize) { | |
cinfo->enable_2pass_quant = TRUE; | |
} else { | |
cinfo->enable_1pass_quant = TRUE; | |
} | |
if (cinfo->enable_1pass_quant) { | |
#ifdef QUANT_1PASS_SUPPORTED | |
jinit_1pass_quantizer(cinfo); | |
master->quantizer_1pass = cinfo->cquantize; | |
#else | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
#endif | |
} | |
/* We use the 2-pass code to map to external colormaps. */ | |
if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) { | |
#ifdef QUANT_2PASS_SUPPORTED | |
jinit_2pass_quantizer(cinfo); | |
master->quantizer_2pass = cinfo->cquantize; | |
#else | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
#endif | |
} | |
/* If both quantizers are initialized, the 2-pass one is left active; | |
* this is necessary for starting with quantization to an external map. | |
*/ | |
} | |
/* Post-processing: in particular, color conversion first */ | |
if (! cinfo->raw_data_out) { | |
if (master->using_merged_upsample) { | |
#ifdef UPSAMPLE_MERGING_SUPPORTED | |
jinit_merged_upsampler(cinfo); /* does color conversion too */ | |
#else | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
#endif | |
} else { | |
jinit_color_deconverter(cinfo); | |
jinit_upsampler(cinfo); | |
} | |
jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant); | |
} | |
/* Inverse DCT */ | |
jinit_inverse_dct(cinfo); | |
/* Entropy decoding: either Huffman or arithmetic coding. */ | |
if (cinfo->arith_code) { | |
ERREXIT(cinfo, JERR_ARITH_NOTIMPL); | |
} else { | |
if (cinfo->progressive_mode) { | |
#ifdef D_PROGRESSIVE_SUPPORTED | |
jinit_phuff_decoder(cinfo); | |
#else | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
#endif | |
} else | |
jinit_huff_decoder(cinfo); | |
} | |
/* Initialize principal buffer controllers. */ | |
use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image; | |
jinit_d_coef_controller(cinfo, use_c_buffer); | |
if (! cinfo->raw_data_out) | |
jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */); | |
/* We can now tell the memory manager to allocate virtual arrays. */ | |
(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); | |
/* Initialize input side of decompressor to consume first scan. */ | |
(*cinfo->inputctl->start_input_pass) (cinfo); | |
#ifdef D_MULTISCAN_FILES_SUPPORTED | |
/* If jpeg_start_decompress will read the whole file, initialize | |
* progress monitoring appropriately. The input step is counted | |
* as one pass. | |
*/ | |
if (cinfo->progress != NULL && ! cinfo->buffered_image && | |
cinfo->inputctl->has_multiple_scans) { | |
int nscans; | |
/* Estimate number of scans to set pass_limit. */ | |
if (cinfo->progressive_mode) { | |
/* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */ | |
nscans = 2 + 3 * cinfo->num_components; | |
} else { | |
/* For a nonprogressive multiscan file, estimate 1 scan per component. */ | |
nscans = cinfo->num_components; | |
} | |
cinfo->progress->pass_counter = 0L; | |
cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans; | |
cinfo->progress->completed_passes = 0; | |
cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2); | |
/* Count the input pass as done */ | |
master->pass_number++; | |
} | |
#endif /* D_MULTISCAN_FILES_SUPPORTED */ | |
} | |
/* | |
* Per-pass setup. | |
* This is called at the beginning of each output pass. We determine which | |
* modules will be active during this pass and give them appropriate | |
* start_pass calls. We also set is_dummy_pass to indicate whether this | |
* is a "real" output pass or a dummy pass for color quantization. | |
* (In the latter case, jdapistd.c will crank the pass to completion.) | |
*/ | |
METHODDEF(void) | |
prepare_for_output_pass (j_decompress_ptr cinfo) | |
{ | |
my_master_ptr master = (my_master_ptr) cinfo->master; | |
if (master->pub.is_dummy_pass) { | |
#ifdef QUANT_2PASS_SUPPORTED | |
/* Final pass of 2-pass quantization */ | |
master->pub.is_dummy_pass = FALSE; | |
(*cinfo->cquantize->start_pass) (cinfo, FALSE); | |
(*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST); | |
(*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST); | |
#else | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
#endif /* QUANT_2PASS_SUPPORTED */ | |
} else { | |
if (cinfo->quantize_colors && cinfo->colormap == NULL) { | |
/* Select new quantization method */ | |
if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) { | |
cinfo->cquantize = master->quantizer_2pass; | |
master->pub.is_dummy_pass = TRUE; | |
} else if (cinfo->enable_1pass_quant) { | |
cinfo->cquantize = master->quantizer_1pass; | |
} else { | |
ERREXIT(cinfo, JERR_MODE_CHANGE); | |
} | |
} | |
(*cinfo->idct->start_pass) (cinfo); | |
(*cinfo->coef->start_output_pass) (cinfo); | |
if (! cinfo->raw_data_out) { | |
if (! master->using_merged_upsample) | |
(*cinfo->cconvert->start_pass) (cinfo); | |
(*cinfo->upsample->start_pass) (cinfo); | |
if (cinfo->quantize_colors) | |
(*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass); | |
(*cinfo->post->start_pass) (cinfo, | |
(master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); | |
(*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); | |
} | |
} | |
/* 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->pass_number + | |
(master->pub.is_dummy_pass ? 2 : 1); | |
/* In buffered-image mode, we assume one more output pass if EOI not | |
* yet reached, but no more passes if EOI has been reached. | |
*/ | |
if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) { | |
cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1); | |
} | |
} | |
} | |
/* | |
* Finish up at end of an output pass. | |
*/ | |
METHODDEF(void) | |
finish_output_pass (j_decompress_ptr cinfo) | |
{ | |
my_master_ptr master = (my_master_ptr) cinfo->master; | |
if (cinfo->quantize_colors) | |
(*cinfo->cquantize->finish_pass) (cinfo); | |
master->pass_number++; | |
} | |
#ifdef D_MULTISCAN_FILES_SUPPORTED | |
/* | |
* Switch to a new external colormap between output passes. | |
*/ | |
GLOBAL(void) | |
jpeg_new_colormap (j_decompress_ptr cinfo) | |
{ | |
my_master_ptr master = (my_master_ptr) cinfo->master; | |
/* Prevent application from calling me at wrong times */ | |
if (cinfo->global_state != DSTATE_BUFIMAGE) | |
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
if (cinfo->quantize_colors && cinfo->enable_external_quant && | |
cinfo->colormap != NULL) { | |
/* Select 2-pass quantizer for external colormap use */ | |
cinfo->cquantize = master->quantizer_2pass; | |
/* Notify quantizer of colormap change */ | |
(*cinfo->cquantize->new_color_map) (cinfo); | |
master->pub.is_dummy_pass = FALSE; /* just in case */ | |
} else | |
ERREXIT(cinfo, JERR_MODE_CHANGE); | |
} | |
#endif /* D_MULTISCAN_FILES_SUPPORTED */ | |
/* | |
* Initialize master decompression control and select active modules. | |
* This is performed at the start of jpeg_start_decompress. | |
*/ | |
GLOBAL(void) | |
jinit_master_decompress (j_decompress_ptr cinfo) | |
{ | |
my_master_ptr master; | |
master = (my_master_ptr) | |
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
SIZEOF(my_decomp_master)); | |
cinfo->master = (struct jpeg_decomp_master *) master; | |
master->pub.prepare_for_output_pass = prepare_for_output_pass; | |
master->pub.finish_output_pass = finish_output_pass; | |
master->pub.is_dummy_pass = FALSE; | |
master_selection(cinfo); | |
} | |
#endif //_FX_JPEG_TURBO_ |