dbf-halloween2015

annotate libs/libjpeg/jdmaster.c @ 3:c37fe5d8a4ed

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windows port
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 01 Nov 2015 06:04:28 +0200
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rev   line source
nuclear@1 1 /*
nuclear@1 2 * jdmaster.c
nuclear@1 3 *
nuclear@1 4 * Copyright (C) 1991-1997, Thomas G. Lane.
nuclear@1 5 * This file is part of the Independent JPEG Group's software.
nuclear@1 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@1 7 *
nuclear@1 8 * This file contains master control logic for the JPEG decompressor.
nuclear@1 9 * These routines are concerned with selecting the modules to be executed
nuclear@1 10 * and with determining the number of passes and the work to be done in each
nuclear@1 11 * pass.
nuclear@1 12 */
nuclear@1 13
nuclear@1 14 #define JPEG_INTERNALS
nuclear@1 15 #include "jinclude.h"
nuclear@1 16 #include "jpeglib.h"
nuclear@1 17
nuclear@1 18
nuclear@1 19 /* Private state */
nuclear@1 20
nuclear@1 21 typedef struct {
nuclear@1 22 struct jpeg_decomp_master pub; /* public fields */
nuclear@1 23
nuclear@1 24 int pass_number; /* # of passes completed */
nuclear@1 25
nuclear@1 26 boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
nuclear@1 27
nuclear@1 28 /* Saved references to initialized quantizer modules,
nuclear@1 29 * in case we need to switch modes.
nuclear@1 30 */
nuclear@1 31 struct jpeg_color_quantizer * quantizer_1pass;
nuclear@1 32 struct jpeg_color_quantizer * quantizer_2pass;
nuclear@1 33 } my_decomp_master;
nuclear@1 34
nuclear@1 35 typedef my_decomp_master * my_master_ptr;
nuclear@1 36
nuclear@1 37
nuclear@1 38 /*
nuclear@1 39 * Determine whether merged upsample/color conversion should be used.
nuclear@1 40 * CRUCIAL: this must match the actual capabilities of jdmerge.c!
nuclear@1 41 */
nuclear@1 42
nuclear@1 43 LOCAL(boolean)
nuclear@1 44 use_merged_upsample (j_decompress_ptr cinfo)
nuclear@1 45 {
nuclear@1 46 #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@1 47 /* Merging is the equivalent of plain box-filter upsampling */
nuclear@1 48 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
nuclear@1 49 return FALSE;
nuclear@1 50 /* jdmerge.c only supports YCC=>RGB color conversion */
nuclear@1 51 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
nuclear@1 52 cinfo->out_color_space != JCS_RGB ||
nuclear@1 53 cinfo->out_color_components != RGB_PIXELSIZE)
nuclear@1 54 return FALSE;
nuclear@1 55 /* and it only handles 2h1v or 2h2v sampling ratios */
nuclear@1 56 if (cinfo->comp_info[0].h_samp_factor != 2 ||
nuclear@1 57 cinfo->comp_info[1].h_samp_factor != 1 ||
nuclear@1 58 cinfo->comp_info[2].h_samp_factor != 1 ||
nuclear@1 59 cinfo->comp_info[0].v_samp_factor > 2 ||
nuclear@1 60 cinfo->comp_info[1].v_samp_factor != 1 ||
nuclear@1 61 cinfo->comp_info[2].v_samp_factor != 1)
nuclear@1 62 return FALSE;
nuclear@1 63 /* furthermore, it doesn't work if we've scaled the IDCTs differently */
nuclear@1 64 if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@1 65 cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@1 66 cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size)
nuclear@1 67 return FALSE;
nuclear@1 68 /* ??? also need to test for upsample-time rescaling, when & if supported */
nuclear@1 69 return TRUE; /* by golly, it'll work... */
nuclear@1 70 #else
nuclear@1 71 return FALSE;
nuclear@1 72 #endif
nuclear@1 73 }
nuclear@1 74
nuclear@1 75
nuclear@1 76 /*
nuclear@1 77 * Compute output image dimensions and related values.
nuclear@1 78 * NOTE: this is exported for possible use by application.
nuclear@1 79 * Hence it mustn't do anything that can't be done twice.
nuclear@1 80 * Also note that it may be called before the master module is initialized!
nuclear@1 81 */
nuclear@1 82
nuclear@1 83 GLOBAL(void)
nuclear@1 84 jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
nuclear@1 85 /* Do computations that are needed before master selection phase */
nuclear@1 86 {
nuclear@1 87 #ifdef IDCT_SCALING_SUPPORTED
nuclear@1 88 int ci;
nuclear@1 89 jpeg_component_info *compptr;
nuclear@1 90 #endif
nuclear@1 91
nuclear@1 92 /* Prevent application from calling me at wrong times */
nuclear@1 93 if (cinfo->global_state != DSTATE_READY)
nuclear@1 94 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@1 95
nuclear@1 96 #ifdef IDCT_SCALING_SUPPORTED
nuclear@1 97
nuclear@1 98 /* Compute actual output image dimensions and DCT scaling choices. */
nuclear@1 99 if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
nuclear@1 100 /* Provide 1/8 scaling */
nuclear@1 101 cinfo->output_width = (JDIMENSION)
nuclear@1 102 jdiv_round_up((long) cinfo->image_width, 8L);
nuclear@1 103 cinfo->output_height = (JDIMENSION)
nuclear@1 104 jdiv_round_up((long) cinfo->image_height, 8L);
nuclear@1 105 cinfo->min_DCT_scaled_size = 1;
nuclear@1 106 } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
nuclear@1 107 /* Provide 1/4 scaling */
nuclear@1 108 cinfo->output_width = (JDIMENSION)
nuclear@1 109 jdiv_round_up((long) cinfo->image_width, 4L);
nuclear@1 110 cinfo->output_height = (JDIMENSION)
nuclear@1 111 jdiv_round_up((long) cinfo->image_height, 4L);
nuclear@1 112 cinfo->min_DCT_scaled_size = 2;
nuclear@1 113 } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
nuclear@1 114 /* Provide 1/2 scaling */
nuclear@1 115 cinfo->output_width = (JDIMENSION)
nuclear@1 116 jdiv_round_up((long) cinfo->image_width, 2L);
nuclear@1 117 cinfo->output_height = (JDIMENSION)
nuclear@1 118 jdiv_round_up((long) cinfo->image_height, 2L);
nuclear@1 119 cinfo->min_DCT_scaled_size = 4;
nuclear@1 120 } else {
nuclear@1 121 /* Provide 1/1 scaling */
nuclear@1 122 cinfo->output_width = cinfo->image_width;
nuclear@1 123 cinfo->output_height = cinfo->image_height;
nuclear@1 124 cinfo->min_DCT_scaled_size = DCTSIZE;
nuclear@1 125 }
nuclear@1 126 /* In selecting the actual DCT scaling for each component, we try to
nuclear@1 127 * scale up the chroma components via IDCT scaling rather than upsampling.
nuclear@1 128 * This saves time if the upsampler gets to use 1:1 scaling.
nuclear@1 129 * Note this code assumes that the supported DCT scalings are powers of 2.
nuclear@1 130 */
nuclear@1 131 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@1 132 ci++, compptr++) {
nuclear@1 133 int ssize = cinfo->min_DCT_scaled_size;
nuclear@1 134 while (ssize < DCTSIZE &&
nuclear@1 135 (compptr->h_samp_factor * ssize * 2 <=
nuclear@1 136 cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) &&
nuclear@1 137 (compptr->v_samp_factor * ssize * 2 <=
nuclear@1 138 cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size)) {
nuclear@1 139 ssize = ssize * 2;
nuclear@1 140 }
nuclear@1 141 compptr->DCT_scaled_size = ssize;
nuclear@1 142 }
nuclear@1 143
nuclear@1 144 /* Recompute downsampled dimensions of components;
nuclear@1 145 * application needs to know these if using raw downsampled data.
nuclear@1 146 */
nuclear@1 147 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@1 148 ci++, compptr++) {
nuclear@1 149 /* Size in samples, after IDCT scaling */
nuclear@1 150 compptr->downsampled_width = (JDIMENSION)
nuclear@1 151 jdiv_round_up((long) cinfo->image_width *
nuclear@1 152 (long) (compptr->h_samp_factor * compptr->DCT_scaled_size),
nuclear@1 153 (long) (cinfo->max_h_samp_factor * DCTSIZE));
nuclear@1 154 compptr->downsampled_height = (JDIMENSION)
nuclear@1 155 jdiv_round_up((long) cinfo->image_height *
nuclear@1 156 (long) (compptr->v_samp_factor * compptr->DCT_scaled_size),
nuclear@1 157 (long) (cinfo->max_v_samp_factor * DCTSIZE));
nuclear@1 158 }
nuclear@1 159
nuclear@1 160 #else /* !IDCT_SCALING_SUPPORTED */
nuclear@1 161
nuclear@1 162 /* Hardwire it to "no scaling" */
nuclear@1 163 cinfo->output_width = cinfo->image_width;
nuclear@1 164 cinfo->output_height = cinfo->image_height;
nuclear@1 165 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
nuclear@1 166 * and has computed unscaled downsampled_width and downsampled_height.
nuclear@1 167 */
nuclear@1 168
nuclear@1 169 #endif /* IDCT_SCALING_SUPPORTED */
nuclear@1 170
nuclear@1 171 /* Report number of components in selected colorspace. */
nuclear@1 172 /* Probably this should be in the color conversion module... */
nuclear@1 173 switch (cinfo->out_color_space) {
nuclear@1 174 case JCS_GRAYSCALE:
nuclear@1 175 cinfo->out_color_components = 1;
nuclear@1 176 break;
nuclear@1 177 case JCS_RGB:
nuclear@1 178 #if RGB_PIXELSIZE != 3
nuclear@1 179 cinfo->out_color_components = RGB_PIXELSIZE;
nuclear@1 180 break;
nuclear@1 181 #endif /* else share code with YCbCr */
nuclear@1 182 case JCS_YCbCr:
nuclear@1 183 cinfo->out_color_components = 3;
nuclear@1 184 break;
nuclear@1 185 case JCS_CMYK:
nuclear@1 186 case JCS_YCCK:
nuclear@1 187 cinfo->out_color_components = 4;
nuclear@1 188 break;
nuclear@1 189 default: /* else must be same colorspace as in file */
nuclear@1 190 cinfo->out_color_components = cinfo->num_components;
nuclear@1 191 break;
nuclear@1 192 }
nuclear@1 193 cinfo->output_components = (cinfo->quantize_colors ? 1 :
nuclear@1 194 cinfo->out_color_components);
nuclear@1 195
nuclear@1 196 /* See if upsampler will want to emit more than one row at a time */
nuclear@1 197 if (use_merged_upsample(cinfo))
nuclear@1 198 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
nuclear@1 199 else
nuclear@1 200 cinfo->rec_outbuf_height = 1;
nuclear@1 201 }
nuclear@1 202
nuclear@1 203
nuclear@1 204 /*
nuclear@1 205 * Several decompression processes need to range-limit values to the range
nuclear@1 206 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
nuclear@1 207 * due to noise introduced by quantization, roundoff error, etc. These
nuclear@1 208 * processes are inner loops and need to be as fast as possible. On most
nuclear@1 209 * machines, particularly CPUs with pipelines or instruction prefetch,
nuclear@1 210 * a (subscript-check-less) C table lookup
nuclear@1 211 * x = sample_range_limit[x];
nuclear@1 212 * is faster than explicit tests
nuclear@1 213 * if (x < 0) x = 0;
nuclear@1 214 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
nuclear@1 215 * These processes all use a common table prepared by the routine below.
nuclear@1 216 *
nuclear@1 217 * For most steps we can mathematically guarantee that the initial value
nuclear@1 218 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
nuclear@1 219 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
nuclear@1 220 * limiting step (just after the IDCT), a wildly out-of-range value is
nuclear@1 221 * possible if the input data is corrupt. To avoid any chance of indexing
nuclear@1 222 * off the end of memory and getting a bad-pointer trap, we perform the
nuclear@1 223 * post-IDCT limiting thus:
nuclear@1 224 * x = range_limit[x & MASK];
nuclear@1 225 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
nuclear@1 226 * samples. Under normal circumstances this is more than enough range and
nuclear@1 227 * a correct output will be generated; with bogus input data the mask will
nuclear@1 228 * cause wraparound, and we will safely generate a bogus-but-in-range output.
nuclear@1 229 * For the post-IDCT step, we want to convert the data from signed to unsigned
nuclear@1 230 * representation by adding CENTERJSAMPLE at the same time that we limit it.
nuclear@1 231 * So the post-IDCT limiting table ends up looking like this:
nuclear@1 232 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
nuclear@1 233 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@1 234 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@1 235 * 0,1,...,CENTERJSAMPLE-1
nuclear@1 236 * Negative inputs select values from the upper half of the table after
nuclear@1 237 * masking.
nuclear@1 238 *
nuclear@1 239 * We can save some space by overlapping the start of the post-IDCT table
nuclear@1 240 * with the simpler range limiting table. The post-IDCT table begins at
nuclear@1 241 * sample_range_limit + CENTERJSAMPLE.
nuclear@1 242 *
nuclear@1 243 * Note that the table is allocated in near data space on PCs; it's small
nuclear@1 244 * enough and used often enough to justify this.
nuclear@1 245 */
nuclear@1 246
nuclear@1 247 LOCAL(void)
nuclear@1 248 prepare_range_limit_table (j_decompress_ptr cinfo)
nuclear@1 249 /* Allocate and fill in the sample_range_limit table */
nuclear@1 250 {
nuclear@1 251 JSAMPLE * table;
nuclear@1 252 int i;
nuclear@1 253
nuclear@1 254 table = (JSAMPLE *)
nuclear@1 255 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@1 256 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@1 257 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
nuclear@1 258 cinfo->sample_range_limit = table;
nuclear@1 259 /* First segment of "simple" table: limit[x] = 0 for x < 0 */
nuclear@1 260 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
nuclear@1 261 /* Main part of "simple" table: limit[x] = x */
nuclear@1 262 for (i = 0; i <= MAXJSAMPLE; i++)
nuclear@1 263 table[i] = (JSAMPLE) i;
nuclear@1 264 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
nuclear@1 265 /* End of simple table, rest of first half of post-IDCT table */
nuclear@1 266 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
nuclear@1 267 table[i] = MAXJSAMPLE;
nuclear@1 268 /* Second half of post-IDCT table */
nuclear@1 269 MEMZERO(table + (2 * (MAXJSAMPLE+1)),
nuclear@1 270 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@1 271 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
nuclear@1 272 cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
nuclear@1 273 }
nuclear@1 274
nuclear@1 275
nuclear@1 276 /*
nuclear@1 277 * Master selection of decompression modules.
nuclear@1 278 * This is done once at jpeg_start_decompress time. We determine
nuclear@1 279 * which modules will be used and give them appropriate initialization calls.
nuclear@1 280 * We also initialize the decompressor input side to begin consuming data.
nuclear@1 281 *
nuclear@1 282 * Since jpeg_read_header has finished, we know what is in the SOF
nuclear@1 283 * and (first) SOS markers. We also have all the application parameter
nuclear@1 284 * settings.
nuclear@1 285 */
nuclear@1 286
nuclear@1 287 LOCAL(void)
nuclear@1 288 master_selection (j_decompress_ptr cinfo)
nuclear@1 289 {
nuclear@1 290 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@1 291 boolean use_c_buffer;
nuclear@1 292 long samplesperrow;
nuclear@1 293 JDIMENSION jd_samplesperrow;
nuclear@1 294
nuclear@1 295 /* Initialize dimensions and other stuff */
nuclear@1 296 jpeg_calc_output_dimensions(cinfo);
nuclear@1 297 prepare_range_limit_table(cinfo);
nuclear@1 298
nuclear@1 299 /* Width of an output scanline must be representable as JDIMENSION. */
nuclear@1 300 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
nuclear@1 301 jd_samplesperrow = (JDIMENSION) samplesperrow;
nuclear@1 302 if ((long) jd_samplesperrow != samplesperrow)
nuclear@1 303 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
nuclear@1 304
nuclear@1 305 /* Initialize my private state */
nuclear@1 306 master->pass_number = 0;
nuclear@1 307 master->using_merged_upsample = use_merged_upsample(cinfo);
nuclear@1 308
nuclear@1 309 /* Color quantizer selection */
nuclear@1 310 master->quantizer_1pass = NULL;
nuclear@1 311 master->quantizer_2pass = NULL;
nuclear@1 312 /* No mode changes if not using buffered-image mode. */
nuclear@1 313 if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
nuclear@1 314 cinfo->enable_1pass_quant = FALSE;
nuclear@1 315 cinfo->enable_external_quant = FALSE;
nuclear@1 316 cinfo->enable_2pass_quant = FALSE;
nuclear@1 317 }
nuclear@1 318 if (cinfo->quantize_colors) {
nuclear@1 319 if (cinfo->raw_data_out)
nuclear@1 320 ERREXIT(cinfo, JERR_NOTIMPL);
nuclear@1 321 /* 2-pass quantizer only works in 3-component color space. */
nuclear@1 322 if (cinfo->out_color_components != 3) {
nuclear@1 323 cinfo->enable_1pass_quant = TRUE;
nuclear@1 324 cinfo->enable_external_quant = FALSE;
nuclear@1 325 cinfo->enable_2pass_quant = FALSE;
nuclear@1 326 cinfo->colormap = NULL;
nuclear@1 327 } else if (cinfo->colormap != NULL) {
nuclear@1 328 cinfo->enable_external_quant = TRUE;
nuclear@1 329 } else if (cinfo->two_pass_quantize) {
nuclear@1 330 cinfo->enable_2pass_quant = TRUE;
nuclear@1 331 } else {
nuclear@1 332 cinfo->enable_1pass_quant = TRUE;
nuclear@1 333 }
nuclear@1 334
nuclear@1 335 if (cinfo->enable_1pass_quant) {
nuclear@1 336 #ifdef QUANT_1PASS_SUPPORTED
nuclear@1 337 jinit_1pass_quantizer(cinfo);
nuclear@1 338 master->quantizer_1pass = cinfo->cquantize;
nuclear@1 339 #else
nuclear@1 340 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@1 341 #endif
nuclear@1 342 }
nuclear@1 343
nuclear@1 344 /* We use the 2-pass code to map to external colormaps. */
nuclear@1 345 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
nuclear@1 346 #ifdef QUANT_2PASS_SUPPORTED
nuclear@1 347 jinit_2pass_quantizer(cinfo);
nuclear@1 348 master->quantizer_2pass = cinfo->cquantize;
nuclear@1 349 #else
nuclear@1 350 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@1 351 #endif
nuclear@1 352 }
nuclear@1 353 /* If both quantizers are initialized, the 2-pass one is left active;
nuclear@1 354 * this is necessary for starting with quantization to an external map.
nuclear@1 355 */
nuclear@1 356 }
nuclear@1 357
nuclear@1 358 /* Post-processing: in particular, color conversion first */
nuclear@1 359 if (! cinfo->raw_data_out) {
nuclear@1 360 if (master->using_merged_upsample) {
nuclear@1 361 #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@1 362 jinit_merged_upsampler(cinfo); /* does color conversion too */
nuclear@1 363 #else
nuclear@1 364 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@1 365 #endif
nuclear@1 366 } else {
nuclear@1 367 jinit_color_deconverter(cinfo);
nuclear@1 368 jinit_upsampler(cinfo);
nuclear@1 369 }
nuclear@1 370 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
nuclear@1 371 }
nuclear@1 372 /* Inverse DCT */
nuclear@1 373 jinit_inverse_dct(cinfo);
nuclear@1 374 /* Entropy decoding: either Huffman or arithmetic coding. */
nuclear@1 375 if (cinfo->arith_code) {
nuclear@1 376 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
nuclear@1 377 } else {
nuclear@1 378 if (cinfo->progressive_mode) {
nuclear@1 379 #ifdef D_PROGRESSIVE_SUPPORTED
nuclear@1 380 jinit_phuff_decoder(cinfo);
nuclear@1 381 #else
nuclear@1 382 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@1 383 #endif
nuclear@1 384 } else
nuclear@1 385 jinit_huff_decoder(cinfo);
nuclear@1 386 }
nuclear@1 387
nuclear@1 388 /* Initialize principal buffer controllers. */
nuclear@1 389 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
nuclear@1 390 jinit_d_coef_controller(cinfo, use_c_buffer);
nuclear@1 391
nuclear@1 392 if (! cinfo->raw_data_out)
nuclear@1 393 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
nuclear@1 394
nuclear@1 395 /* We can now tell the memory manager to allocate virtual arrays. */
nuclear@1 396 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
nuclear@1 397
nuclear@1 398 /* Initialize input side of decompressor to consume first scan. */
nuclear@1 399 (*cinfo->inputctl->start_input_pass) (cinfo);
nuclear@1 400
nuclear@1 401 #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@1 402 /* If jpeg_start_decompress will read the whole file, initialize
nuclear@1 403 * progress monitoring appropriately. The input step is counted
nuclear@1 404 * as one pass.
nuclear@1 405 */
nuclear@1 406 if (cinfo->progress != NULL && ! cinfo->buffered_image &&
nuclear@1 407 cinfo->inputctl->has_multiple_scans) {
nuclear@1 408 int nscans;
nuclear@1 409 /* Estimate number of scans to set pass_limit. */
nuclear@1 410 if (cinfo->progressive_mode) {
nuclear@1 411 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
nuclear@1 412 nscans = 2 + 3 * cinfo->num_components;
nuclear@1 413 } else {
nuclear@1 414 /* For a nonprogressive multiscan file, estimate 1 scan per component. */
nuclear@1 415 nscans = cinfo->num_components;
nuclear@1 416 }
nuclear@1 417 cinfo->progress->pass_counter = 0L;
nuclear@1 418 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
nuclear@1 419 cinfo->progress->completed_passes = 0;
nuclear@1 420 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
nuclear@1 421 /* Count the input pass as done */
nuclear@1 422 master->pass_number++;
nuclear@1 423 }
nuclear@1 424 #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@1 425 }
nuclear@1 426
nuclear@1 427
nuclear@1 428 /*
nuclear@1 429 * Per-pass setup.
nuclear@1 430 * This is called at the beginning of each output pass. We determine which
nuclear@1 431 * modules will be active during this pass and give them appropriate
nuclear@1 432 * start_pass calls. We also set is_dummy_pass to indicate whether this
nuclear@1 433 * is a "real" output pass or a dummy pass for color quantization.
nuclear@1 434 * (In the latter case, jdapistd.c will crank the pass to completion.)
nuclear@1 435 */
nuclear@1 436
nuclear@1 437 METHODDEF(void)
nuclear@1 438 prepare_for_output_pass (j_decompress_ptr cinfo)
nuclear@1 439 {
nuclear@1 440 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@1 441
nuclear@1 442 if (master->pub.is_dummy_pass) {
nuclear@1 443 #ifdef QUANT_2PASS_SUPPORTED
nuclear@1 444 /* Final pass of 2-pass quantization */
nuclear@1 445 master->pub.is_dummy_pass = FALSE;
nuclear@1 446 (*cinfo->cquantize->start_pass) (cinfo, FALSE);
nuclear@1 447 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@1 448 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@1 449 #else
nuclear@1 450 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@1 451 #endif /* QUANT_2PASS_SUPPORTED */
nuclear@1 452 } else {
nuclear@1 453 if (cinfo->quantize_colors && cinfo->colormap == NULL) {
nuclear@1 454 /* Select new quantization method */
nuclear@1 455 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
nuclear@1 456 cinfo->cquantize = master->quantizer_2pass;
nuclear@1 457 master->pub.is_dummy_pass = TRUE;
nuclear@1 458 } else if (cinfo->enable_1pass_quant) {
nuclear@1 459 cinfo->cquantize = master->quantizer_1pass;
nuclear@1 460 } else {
nuclear@1 461 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@1 462 }
nuclear@1 463 }
nuclear@1 464 (*cinfo->idct->start_pass) (cinfo);
nuclear@1 465 (*cinfo->coef->start_output_pass) (cinfo);
nuclear@1 466 if (! cinfo->raw_data_out) {
nuclear@1 467 if (! master->using_merged_upsample)
nuclear@1 468 (*cinfo->cconvert->start_pass) (cinfo);
nuclear@1 469 (*cinfo->upsample->start_pass) (cinfo);
nuclear@1 470 if (cinfo->quantize_colors)
nuclear@1 471 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
nuclear@1 472 (*cinfo->post->start_pass) (cinfo,
nuclear@1 473 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
nuclear@1 474 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
nuclear@1 475 }
nuclear@1 476 }
nuclear@1 477
nuclear@1 478 /* Set up progress monitor's pass info if present */
nuclear@1 479 if (cinfo->progress != NULL) {
nuclear@1 480 cinfo->progress->completed_passes = master->pass_number;
nuclear@1 481 cinfo->progress->total_passes = master->pass_number +
nuclear@1 482 (master->pub.is_dummy_pass ? 2 : 1);
nuclear@1 483 /* In buffered-image mode, we assume one more output pass if EOI not
nuclear@1 484 * yet reached, but no more passes if EOI has been reached.
nuclear@1 485 */
nuclear@1 486 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
nuclear@1 487 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
nuclear@1 488 }
nuclear@1 489 }
nuclear@1 490 }
nuclear@1 491
nuclear@1 492
nuclear@1 493 /*
nuclear@1 494 * Finish up at end of an output pass.
nuclear@1 495 */
nuclear@1 496
nuclear@1 497 METHODDEF(void)
nuclear@1 498 finish_output_pass (j_decompress_ptr cinfo)
nuclear@1 499 {
nuclear@1 500 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@1 501
nuclear@1 502 if (cinfo->quantize_colors)
nuclear@1 503 (*cinfo->cquantize->finish_pass) (cinfo);
nuclear@1 504 master->pass_number++;
nuclear@1 505 }
nuclear@1 506
nuclear@1 507
nuclear@1 508 #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@1 509
nuclear@1 510 /*
nuclear@1 511 * Switch to a new external colormap between output passes.
nuclear@1 512 */
nuclear@1 513
nuclear@1 514 GLOBAL(void)
nuclear@1 515 jpeg_new_colormap (j_decompress_ptr cinfo)
nuclear@1 516 {
nuclear@1 517 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@1 518
nuclear@1 519 /* Prevent application from calling me at wrong times */
nuclear@1 520 if (cinfo->global_state != DSTATE_BUFIMAGE)
nuclear@1 521 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@1 522
nuclear@1 523 if (cinfo->quantize_colors && cinfo->enable_external_quant &&
nuclear@1 524 cinfo->colormap != NULL) {
nuclear@1 525 /* Select 2-pass quantizer for external colormap use */
nuclear@1 526 cinfo->cquantize = master->quantizer_2pass;
nuclear@1 527 /* Notify quantizer of colormap change */
nuclear@1 528 (*cinfo->cquantize->new_color_map) (cinfo);
nuclear@1 529 master->pub.is_dummy_pass = FALSE; /* just in case */
nuclear@1 530 } else
nuclear@1 531 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@1 532 }
nuclear@1 533
nuclear@1 534 #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@1 535
nuclear@1 536
nuclear@1 537 /*
nuclear@1 538 * Initialize master decompression control and select active modules.
nuclear@1 539 * This is performed at the start of jpeg_start_decompress.
nuclear@1 540 */
nuclear@1 541
nuclear@1 542 GLOBAL(void)
nuclear@1 543 jinit_master_decompress (j_decompress_ptr cinfo)
nuclear@1 544 {
nuclear@1 545 my_master_ptr master;
nuclear@1 546
nuclear@1 547 master = (my_master_ptr)
nuclear@1 548 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@1 549 SIZEOF(my_decomp_master));
nuclear@1 550 cinfo->master = (struct jpeg_decomp_master *) master;
nuclear@1 551 master->pub.prepare_for_output_pass = prepare_for_output_pass;
nuclear@1 552 master->pub.finish_output_pass = finish_output_pass;
nuclear@1 553
nuclear@1 554 master->pub.is_dummy_pass = FALSE;
nuclear@1 555
nuclear@1 556 master_selection(cinfo);
nuclear@1 557 }