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annotate libs/libjpeg/jdmaster.c @ 19:94b8ef9b8caa

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restored C++
author John Tsiombikas <nuclear@member.fsf.org>
date Wed, 10 Jun 2015 22:28:48 +0300
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nuclear@14 1 /*
nuclear@14 2 * jdmaster.c
nuclear@14 3 *
nuclear@14 4 * Copyright (C) 1991-1997, Thomas G. Lane.
nuclear@14 5 * This file is part of the Independent JPEG Group's software.
nuclear@14 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@14 7 *
nuclear@14 8 * This file contains master control logic for the JPEG decompressor.
nuclear@14 9 * These routines are concerned with selecting the modules to be executed
nuclear@14 10 * and with determining the number of passes and the work to be done in each
nuclear@14 11 * pass.
nuclear@14 12 */
nuclear@14 13
nuclear@14 14 #define JPEG_INTERNALS
nuclear@14 15 #include "jinclude.h"
nuclear@14 16 #include "jpeglib.h"
nuclear@14 17
nuclear@14 18
nuclear@14 19 /* Private state */
nuclear@14 20
nuclear@14 21 typedef struct {
nuclear@14 22 struct jpeg_decomp_master pub; /* public fields */
nuclear@14 23
nuclear@14 24 int pass_number; /* # of passes completed */
nuclear@14 25
nuclear@14 26 boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
nuclear@14 27
nuclear@14 28 /* Saved references to initialized quantizer modules,
nuclear@14 29 * in case we need to switch modes.
nuclear@14 30 */
nuclear@14 31 struct jpeg_color_quantizer * quantizer_1pass;
nuclear@14 32 struct jpeg_color_quantizer * quantizer_2pass;
nuclear@14 33 } my_decomp_master;
nuclear@14 34
nuclear@14 35 typedef my_decomp_master * my_master_ptr;
nuclear@14 36
nuclear@14 37
nuclear@14 38 /*
nuclear@14 39 * Determine whether merged upsample/color conversion should be used.
nuclear@14 40 * CRUCIAL: this must match the actual capabilities of jdmerge.c!
nuclear@14 41 */
nuclear@14 42
nuclear@14 43 LOCAL(boolean)
nuclear@14 44 use_merged_upsample (j_decompress_ptr cinfo)
nuclear@14 45 {
nuclear@14 46 #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@14 47 /* Merging is the equivalent of plain box-filter upsampling */
nuclear@14 48 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
nuclear@14 49 return FALSE;
nuclear@14 50 /* jdmerge.c only supports YCC=>RGB color conversion */
nuclear@14 51 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
nuclear@14 52 cinfo->out_color_space != JCS_RGB ||
nuclear@14 53 cinfo->out_color_components != RGB_PIXELSIZE)
nuclear@14 54 return FALSE;
nuclear@14 55 /* and it only handles 2h1v or 2h2v sampling ratios */
nuclear@14 56 if (cinfo->comp_info[0].h_samp_factor != 2 ||
nuclear@14 57 cinfo->comp_info[1].h_samp_factor != 1 ||
nuclear@14 58 cinfo->comp_info[2].h_samp_factor != 1 ||
nuclear@14 59 cinfo->comp_info[0].v_samp_factor > 2 ||
nuclear@14 60 cinfo->comp_info[1].v_samp_factor != 1 ||
nuclear@14 61 cinfo->comp_info[2].v_samp_factor != 1)
nuclear@14 62 return FALSE;
nuclear@14 63 /* furthermore, it doesn't work if we've scaled the IDCTs differently */
nuclear@14 64 if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@14 65 cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
nuclear@14 66 cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size)
nuclear@14 67 return FALSE;
nuclear@14 68 /* ??? also need to test for upsample-time rescaling, when & if supported */
nuclear@14 69 return TRUE; /* by golly, it'll work... */
nuclear@14 70 #else
nuclear@14 71 return FALSE;
nuclear@14 72 #endif
nuclear@14 73 }
nuclear@14 74
nuclear@14 75
nuclear@14 76 /*
nuclear@14 77 * Compute output image dimensions and related values.
nuclear@14 78 * NOTE: this is exported for possible use by application.
nuclear@14 79 * Hence it mustn't do anything that can't be done twice.
nuclear@14 80 * Also note that it may be called before the master module is initialized!
nuclear@14 81 */
nuclear@14 82
nuclear@14 83 GLOBAL(void)
nuclear@14 84 jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
nuclear@14 85 /* Do computations that are needed before master selection phase */
nuclear@14 86 {
nuclear@14 87 #ifdef IDCT_SCALING_SUPPORTED
nuclear@14 88 int ci;
nuclear@14 89 jpeg_component_info *compptr;
nuclear@14 90 #endif
nuclear@14 91
nuclear@14 92 /* Prevent application from calling me at wrong times */
nuclear@14 93 if (cinfo->global_state != DSTATE_READY)
nuclear@14 94 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@14 95
nuclear@14 96 #ifdef IDCT_SCALING_SUPPORTED
nuclear@14 97
nuclear@14 98 /* Compute actual output image dimensions and DCT scaling choices. */
nuclear@14 99 if (cinfo->scale_num * 8 <= cinfo->scale_denom) {
nuclear@14 100 /* Provide 1/8 scaling */
nuclear@14 101 cinfo->output_width = (JDIMENSION)
nuclear@14 102 jdiv_round_up((long) cinfo->image_width, 8L);
nuclear@14 103 cinfo->output_height = (JDIMENSION)
nuclear@14 104 jdiv_round_up((long) cinfo->image_height, 8L);
nuclear@14 105 cinfo->min_DCT_scaled_size = 1;
nuclear@14 106 } else if (cinfo->scale_num * 4 <= cinfo->scale_denom) {
nuclear@14 107 /* Provide 1/4 scaling */
nuclear@14 108 cinfo->output_width = (JDIMENSION)
nuclear@14 109 jdiv_round_up((long) cinfo->image_width, 4L);
nuclear@14 110 cinfo->output_height = (JDIMENSION)
nuclear@14 111 jdiv_round_up((long) cinfo->image_height, 4L);
nuclear@14 112 cinfo->min_DCT_scaled_size = 2;
nuclear@14 113 } else if (cinfo->scale_num * 2 <= cinfo->scale_denom) {
nuclear@14 114 /* Provide 1/2 scaling */
nuclear@14 115 cinfo->output_width = (JDIMENSION)
nuclear@14 116 jdiv_round_up((long) cinfo->image_width, 2L);
nuclear@14 117 cinfo->output_height = (JDIMENSION)
nuclear@14 118 jdiv_round_up((long) cinfo->image_height, 2L);
nuclear@14 119 cinfo->min_DCT_scaled_size = 4;
nuclear@14 120 } else {
nuclear@14 121 /* Provide 1/1 scaling */
nuclear@14 122 cinfo->output_width = cinfo->image_width;
nuclear@14 123 cinfo->output_height = cinfo->image_height;
nuclear@14 124 cinfo->min_DCT_scaled_size = DCTSIZE;
nuclear@14 125 }
nuclear@14 126 /* In selecting the actual DCT scaling for each component, we try to
nuclear@14 127 * scale up the chroma components via IDCT scaling rather than upsampling.
nuclear@14 128 * This saves time if the upsampler gets to use 1:1 scaling.
nuclear@14 129 * Note this code assumes that the supported DCT scalings are powers of 2.
nuclear@14 130 */
nuclear@14 131 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@14 132 ci++, compptr++) {
nuclear@14 133 int ssize = cinfo->min_DCT_scaled_size;
nuclear@14 134 while (ssize < DCTSIZE &&
nuclear@14 135 (compptr->h_samp_factor * ssize * 2 <=
nuclear@14 136 cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) &&
nuclear@14 137 (compptr->v_samp_factor * ssize * 2 <=
nuclear@14 138 cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size)) {
nuclear@14 139 ssize = ssize * 2;
nuclear@14 140 }
nuclear@14 141 compptr->DCT_scaled_size = ssize;
nuclear@14 142 }
nuclear@14 143
nuclear@14 144 /* Recompute downsampled dimensions of components;
nuclear@14 145 * application needs to know these if using raw downsampled data.
nuclear@14 146 */
nuclear@14 147 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@14 148 ci++, compptr++) {
nuclear@14 149 /* Size in samples, after IDCT scaling */
nuclear@14 150 compptr->downsampled_width = (JDIMENSION)
nuclear@14 151 jdiv_round_up((long) cinfo->image_width *
nuclear@14 152 (long) (compptr->h_samp_factor * compptr->DCT_scaled_size),
nuclear@14 153 (long) (cinfo->max_h_samp_factor * DCTSIZE));
nuclear@14 154 compptr->downsampled_height = (JDIMENSION)
nuclear@14 155 jdiv_round_up((long) cinfo->image_height *
nuclear@14 156 (long) (compptr->v_samp_factor * compptr->DCT_scaled_size),
nuclear@14 157 (long) (cinfo->max_v_samp_factor * DCTSIZE));
nuclear@14 158 }
nuclear@14 159
nuclear@14 160 #else /* !IDCT_SCALING_SUPPORTED */
nuclear@14 161
nuclear@14 162 /* Hardwire it to "no scaling" */
nuclear@14 163 cinfo->output_width = cinfo->image_width;
nuclear@14 164 cinfo->output_height = cinfo->image_height;
nuclear@14 165 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
nuclear@14 166 * and has computed unscaled downsampled_width and downsampled_height.
nuclear@14 167 */
nuclear@14 168
nuclear@14 169 #endif /* IDCT_SCALING_SUPPORTED */
nuclear@14 170
nuclear@14 171 /* Report number of components in selected colorspace. */
nuclear@14 172 /* Probably this should be in the color conversion module... */
nuclear@14 173 switch (cinfo->out_color_space) {
nuclear@14 174 case JCS_GRAYSCALE:
nuclear@14 175 cinfo->out_color_components = 1;
nuclear@14 176 break;
nuclear@14 177 case JCS_RGB:
nuclear@14 178 #if RGB_PIXELSIZE != 3
nuclear@14 179 cinfo->out_color_components = RGB_PIXELSIZE;
nuclear@14 180 break;
nuclear@14 181 #endif /* else share code with YCbCr */
nuclear@14 182 case JCS_YCbCr:
nuclear@14 183 cinfo->out_color_components = 3;
nuclear@14 184 break;
nuclear@14 185 case JCS_CMYK:
nuclear@14 186 case JCS_YCCK:
nuclear@14 187 cinfo->out_color_components = 4;
nuclear@14 188 break;
nuclear@14 189 default: /* else must be same colorspace as in file */
nuclear@14 190 cinfo->out_color_components = cinfo->num_components;
nuclear@14 191 break;
nuclear@14 192 }
nuclear@14 193 cinfo->output_components = (cinfo->quantize_colors ? 1 :
nuclear@14 194 cinfo->out_color_components);
nuclear@14 195
nuclear@14 196 /* See if upsampler will want to emit more than one row at a time */
nuclear@14 197 if (use_merged_upsample(cinfo))
nuclear@14 198 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
nuclear@14 199 else
nuclear@14 200 cinfo->rec_outbuf_height = 1;
nuclear@14 201 }
nuclear@14 202
nuclear@14 203
nuclear@14 204 /*
nuclear@14 205 * Several decompression processes need to range-limit values to the range
nuclear@14 206 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
nuclear@14 207 * due to noise introduced by quantization, roundoff error, etc. These
nuclear@14 208 * processes are inner loops and need to be as fast as possible. On most
nuclear@14 209 * machines, particularly CPUs with pipelines or instruction prefetch,
nuclear@14 210 * a (subscript-check-less) C table lookup
nuclear@14 211 * x = sample_range_limit[x];
nuclear@14 212 * is faster than explicit tests
nuclear@14 213 * if (x < 0) x = 0;
nuclear@14 214 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
nuclear@14 215 * These processes all use a common table prepared by the routine below.
nuclear@14 216 *
nuclear@14 217 * For most steps we can mathematically guarantee that the initial value
nuclear@14 218 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
nuclear@14 219 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
nuclear@14 220 * limiting step (just after the IDCT), a wildly out-of-range value is
nuclear@14 221 * possible if the input data is corrupt. To avoid any chance of indexing
nuclear@14 222 * off the end of memory and getting a bad-pointer trap, we perform the
nuclear@14 223 * post-IDCT limiting thus:
nuclear@14 224 * x = range_limit[x & MASK];
nuclear@14 225 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
nuclear@14 226 * samples. Under normal circumstances this is more than enough range and
nuclear@14 227 * a correct output will be generated; with bogus input data the mask will
nuclear@14 228 * cause wraparound, and we will safely generate a bogus-but-in-range output.
nuclear@14 229 * For the post-IDCT step, we want to convert the data from signed to unsigned
nuclear@14 230 * representation by adding CENTERJSAMPLE at the same time that we limit it.
nuclear@14 231 * So the post-IDCT limiting table ends up looking like this:
nuclear@14 232 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
nuclear@14 233 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@14 234 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
nuclear@14 235 * 0,1,...,CENTERJSAMPLE-1
nuclear@14 236 * Negative inputs select values from the upper half of the table after
nuclear@14 237 * masking.
nuclear@14 238 *
nuclear@14 239 * We can save some space by overlapping the start of the post-IDCT table
nuclear@14 240 * with the simpler range limiting table. The post-IDCT table begins at
nuclear@14 241 * sample_range_limit + CENTERJSAMPLE.
nuclear@14 242 *
nuclear@14 243 * Note that the table is allocated in near data space on PCs; it's small
nuclear@14 244 * enough and used often enough to justify this.
nuclear@14 245 */
nuclear@14 246
nuclear@14 247 LOCAL(void)
nuclear@14 248 prepare_range_limit_table (j_decompress_ptr cinfo)
nuclear@14 249 /* Allocate and fill in the sample_range_limit table */
nuclear@14 250 {
nuclear@14 251 JSAMPLE * table;
nuclear@14 252 int i;
nuclear@14 253
nuclear@14 254 table = (JSAMPLE *)
nuclear@14 255 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 256 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@14 257 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
nuclear@14 258 cinfo->sample_range_limit = table;
nuclear@14 259 /* First segment of "simple" table: limit[x] = 0 for x < 0 */
nuclear@14 260 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
nuclear@14 261 /* Main part of "simple" table: limit[x] = x */
nuclear@14 262 for (i = 0; i <= MAXJSAMPLE; i++)
nuclear@14 263 table[i] = (JSAMPLE) i;
nuclear@14 264 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
nuclear@14 265 /* End of simple table, rest of first half of post-IDCT table */
nuclear@14 266 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
nuclear@14 267 table[i] = MAXJSAMPLE;
nuclear@14 268 /* Second half of post-IDCT table */
nuclear@14 269 MEMZERO(table + (2 * (MAXJSAMPLE+1)),
nuclear@14 270 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
nuclear@14 271 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
nuclear@14 272 cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
nuclear@14 273 }
nuclear@14 274
nuclear@14 275
nuclear@14 276 /*
nuclear@14 277 * Master selection of decompression modules.
nuclear@14 278 * This is done once at jpeg_start_decompress time. We determine
nuclear@14 279 * which modules will be used and give them appropriate initialization calls.
nuclear@14 280 * We also initialize the decompressor input side to begin consuming data.
nuclear@14 281 *
nuclear@14 282 * Since jpeg_read_header has finished, we know what is in the SOF
nuclear@14 283 * and (first) SOS markers. We also have all the application parameter
nuclear@14 284 * settings.
nuclear@14 285 */
nuclear@14 286
nuclear@14 287 LOCAL(void)
nuclear@14 288 master_selection (j_decompress_ptr cinfo)
nuclear@14 289 {
nuclear@14 290 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@14 291 boolean use_c_buffer;
nuclear@14 292 long samplesperrow;
nuclear@14 293 JDIMENSION jd_samplesperrow;
nuclear@14 294
nuclear@14 295 /* Initialize dimensions and other stuff */
nuclear@14 296 jpeg_calc_output_dimensions(cinfo);
nuclear@14 297 prepare_range_limit_table(cinfo);
nuclear@14 298
nuclear@14 299 /* Width of an output scanline must be representable as JDIMENSION. */
nuclear@14 300 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
nuclear@14 301 jd_samplesperrow = (JDIMENSION) samplesperrow;
nuclear@14 302 if ((long) jd_samplesperrow != samplesperrow)
nuclear@14 303 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
nuclear@14 304
nuclear@14 305 /* Initialize my private state */
nuclear@14 306 master->pass_number = 0;
nuclear@14 307 master->using_merged_upsample = use_merged_upsample(cinfo);
nuclear@14 308
nuclear@14 309 /* Color quantizer selection */
nuclear@14 310 master->quantizer_1pass = NULL;
nuclear@14 311 master->quantizer_2pass = NULL;
nuclear@14 312 /* No mode changes if not using buffered-image mode. */
nuclear@14 313 if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
nuclear@14 314 cinfo->enable_1pass_quant = FALSE;
nuclear@14 315 cinfo->enable_external_quant = FALSE;
nuclear@14 316 cinfo->enable_2pass_quant = FALSE;
nuclear@14 317 }
nuclear@14 318 if (cinfo->quantize_colors) {
nuclear@14 319 if (cinfo->raw_data_out)
nuclear@14 320 ERREXIT(cinfo, JERR_NOTIMPL);
nuclear@14 321 /* 2-pass quantizer only works in 3-component color space. */
nuclear@14 322 if (cinfo->out_color_components != 3) {
nuclear@14 323 cinfo->enable_1pass_quant = TRUE;
nuclear@14 324 cinfo->enable_external_quant = FALSE;
nuclear@14 325 cinfo->enable_2pass_quant = FALSE;
nuclear@14 326 cinfo->colormap = NULL;
nuclear@14 327 } else if (cinfo->colormap != NULL) {
nuclear@14 328 cinfo->enable_external_quant = TRUE;
nuclear@14 329 } else if (cinfo->two_pass_quantize) {
nuclear@14 330 cinfo->enable_2pass_quant = TRUE;
nuclear@14 331 } else {
nuclear@14 332 cinfo->enable_1pass_quant = TRUE;
nuclear@14 333 }
nuclear@14 334
nuclear@14 335 if (cinfo->enable_1pass_quant) {
nuclear@14 336 #ifdef QUANT_1PASS_SUPPORTED
nuclear@14 337 jinit_1pass_quantizer(cinfo);
nuclear@14 338 master->quantizer_1pass = cinfo->cquantize;
nuclear@14 339 #else
nuclear@14 340 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 341 #endif
nuclear@14 342 }
nuclear@14 343
nuclear@14 344 /* We use the 2-pass code to map to external colormaps. */
nuclear@14 345 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
nuclear@14 346 #ifdef QUANT_2PASS_SUPPORTED
nuclear@14 347 jinit_2pass_quantizer(cinfo);
nuclear@14 348 master->quantizer_2pass = cinfo->cquantize;
nuclear@14 349 #else
nuclear@14 350 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 351 #endif
nuclear@14 352 }
nuclear@14 353 /* If both quantizers are initialized, the 2-pass one is left active;
nuclear@14 354 * this is necessary for starting with quantization to an external map.
nuclear@14 355 */
nuclear@14 356 }
nuclear@14 357
nuclear@14 358 /* Post-processing: in particular, color conversion first */
nuclear@14 359 if (! cinfo->raw_data_out) {
nuclear@14 360 if (master->using_merged_upsample) {
nuclear@14 361 #ifdef UPSAMPLE_MERGING_SUPPORTED
nuclear@14 362 jinit_merged_upsampler(cinfo); /* does color conversion too */
nuclear@14 363 #else
nuclear@14 364 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 365 #endif
nuclear@14 366 } else {
nuclear@14 367 jinit_color_deconverter(cinfo);
nuclear@14 368 jinit_upsampler(cinfo);
nuclear@14 369 }
nuclear@14 370 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
nuclear@14 371 }
nuclear@14 372 /* Inverse DCT */
nuclear@14 373 jinit_inverse_dct(cinfo);
nuclear@14 374 /* Entropy decoding: either Huffman or arithmetic coding. */
nuclear@14 375 if (cinfo->arith_code) {
nuclear@14 376 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
nuclear@14 377 } else {
nuclear@14 378 if (cinfo->progressive_mode) {
nuclear@14 379 #ifdef D_PROGRESSIVE_SUPPORTED
nuclear@14 380 jinit_phuff_decoder(cinfo);
nuclear@14 381 #else
nuclear@14 382 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 383 #endif
nuclear@14 384 } else
nuclear@14 385 jinit_huff_decoder(cinfo);
nuclear@14 386 }
nuclear@14 387
nuclear@14 388 /* Initialize principal buffer controllers. */
nuclear@14 389 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
nuclear@14 390 jinit_d_coef_controller(cinfo, use_c_buffer);
nuclear@14 391
nuclear@14 392 if (! cinfo->raw_data_out)
nuclear@14 393 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
nuclear@14 394
nuclear@14 395 /* We can now tell the memory manager to allocate virtual arrays. */
nuclear@14 396 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
nuclear@14 397
nuclear@14 398 /* Initialize input side of decompressor to consume first scan. */
nuclear@14 399 (*cinfo->inputctl->start_input_pass) (cinfo);
nuclear@14 400
nuclear@14 401 #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@14 402 /* If jpeg_start_decompress will read the whole file, initialize
nuclear@14 403 * progress monitoring appropriately. The input step is counted
nuclear@14 404 * as one pass.
nuclear@14 405 */
nuclear@14 406 if (cinfo->progress != NULL && ! cinfo->buffered_image &&
nuclear@14 407 cinfo->inputctl->has_multiple_scans) {
nuclear@14 408 int nscans;
nuclear@14 409 /* Estimate number of scans to set pass_limit. */
nuclear@14 410 if (cinfo->progressive_mode) {
nuclear@14 411 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
nuclear@14 412 nscans = 2 + 3 * cinfo->num_components;
nuclear@14 413 } else {
nuclear@14 414 /* For a nonprogressive multiscan file, estimate 1 scan per component. */
nuclear@14 415 nscans = cinfo->num_components;
nuclear@14 416 }
nuclear@14 417 cinfo->progress->pass_counter = 0L;
nuclear@14 418 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
nuclear@14 419 cinfo->progress->completed_passes = 0;
nuclear@14 420 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
nuclear@14 421 /* Count the input pass as done */
nuclear@14 422 master->pass_number++;
nuclear@14 423 }
nuclear@14 424 #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@14 425 }
nuclear@14 426
nuclear@14 427
nuclear@14 428 /*
nuclear@14 429 * Per-pass setup.
nuclear@14 430 * This is called at the beginning of each output pass. We determine which
nuclear@14 431 * modules will be active during this pass and give them appropriate
nuclear@14 432 * start_pass calls. We also set is_dummy_pass to indicate whether this
nuclear@14 433 * is a "real" output pass or a dummy pass for color quantization.
nuclear@14 434 * (In the latter case, jdapistd.c will crank the pass to completion.)
nuclear@14 435 */
nuclear@14 436
nuclear@14 437 METHODDEF(void)
nuclear@14 438 prepare_for_output_pass (j_decompress_ptr cinfo)
nuclear@14 439 {
nuclear@14 440 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@14 441
nuclear@14 442 if (master->pub.is_dummy_pass) {
nuclear@14 443 #ifdef QUANT_2PASS_SUPPORTED
nuclear@14 444 /* Final pass of 2-pass quantization */
nuclear@14 445 master->pub.is_dummy_pass = FALSE;
nuclear@14 446 (*cinfo->cquantize->start_pass) (cinfo, FALSE);
nuclear@14 447 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@14 448 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
nuclear@14 449 #else
nuclear@14 450 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 451 #endif /* QUANT_2PASS_SUPPORTED */
nuclear@14 452 } else {
nuclear@14 453 if (cinfo->quantize_colors && cinfo->colormap == NULL) {
nuclear@14 454 /* Select new quantization method */
nuclear@14 455 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
nuclear@14 456 cinfo->cquantize = master->quantizer_2pass;
nuclear@14 457 master->pub.is_dummy_pass = TRUE;
nuclear@14 458 } else if (cinfo->enable_1pass_quant) {
nuclear@14 459 cinfo->cquantize = master->quantizer_1pass;
nuclear@14 460 } else {
nuclear@14 461 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@14 462 }
nuclear@14 463 }
nuclear@14 464 (*cinfo->idct->start_pass) (cinfo);
nuclear@14 465 (*cinfo->coef->start_output_pass) (cinfo);
nuclear@14 466 if (! cinfo->raw_data_out) {
nuclear@14 467 if (! master->using_merged_upsample)
nuclear@14 468 (*cinfo->cconvert->start_pass) (cinfo);
nuclear@14 469 (*cinfo->upsample->start_pass) (cinfo);
nuclear@14 470 if (cinfo->quantize_colors)
nuclear@14 471 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
nuclear@14 472 (*cinfo->post->start_pass) (cinfo,
nuclear@14 473 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
nuclear@14 474 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
nuclear@14 475 }
nuclear@14 476 }
nuclear@14 477
nuclear@14 478 /* Set up progress monitor's pass info if present */
nuclear@14 479 if (cinfo->progress != NULL) {
nuclear@14 480 cinfo->progress->completed_passes = master->pass_number;
nuclear@14 481 cinfo->progress->total_passes = master->pass_number +
nuclear@14 482 (master->pub.is_dummy_pass ? 2 : 1);
nuclear@14 483 /* In buffered-image mode, we assume one more output pass if EOI not
nuclear@14 484 * yet reached, but no more passes if EOI has been reached.
nuclear@14 485 */
nuclear@14 486 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
nuclear@14 487 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
nuclear@14 488 }
nuclear@14 489 }
nuclear@14 490 }
nuclear@14 491
nuclear@14 492
nuclear@14 493 /*
nuclear@14 494 * Finish up at end of an output pass.
nuclear@14 495 */
nuclear@14 496
nuclear@14 497 METHODDEF(void)
nuclear@14 498 finish_output_pass (j_decompress_ptr cinfo)
nuclear@14 499 {
nuclear@14 500 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@14 501
nuclear@14 502 if (cinfo->quantize_colors)
nuclear@14 503 (*cinfo->cquantize->finish_pass) (cinfo);
nuclear@14 504 master->pass_number++;
nuclear@14 505 }
nuclear@14 506
nuclear@14 507
nuclear@14 508 #ifdef D_MULTISCAN_FILES_SUPPORTED
nuclear@14 509
nuclear@14 510 /*
nuclear@14 511 * Switch to a new external colormap between output passes.
nuclear@14 512 */
nuclear@14 513
nuclear@14 514 GLOBAL(void)
nuclear@14 515 jpeg_new_colormap (j_decompress_ptr cinfo)
nuclear@14 516 {
nuclear@14 517 my_master_ptr master = (my_master_ptr) cinfo->master;
nuclear@14 518
nuclear@14 519 /* Prevent application from calling me at wrong times */
nuclear@14 520 if (cinfo->global_state != DSTATE_BUFIMAGE)
nuclear@14 521 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@14 522
nuclear@14 523 if (cinfo->quantize_colors && cinfo->enable_external_quant &&
nuclear@14 524 cinfo->colormap != NULL) {
nuclear@14 525 /* Select 2-pass quantizer for external colormap use */
nuclear@14 526 cinfo->cquantize = master->quantizer_2pass;
nuclear@14 527 /* Notify quantizer of colormap change */
nuclear@14 528 (*cinfo->cquantize->new_color_map) (cinfo);
nuclear@14 529 master->pub.is_dummy_pass = FALSE; /* just in case */
nuclear@14 530 } else
nuclear@14 531 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@14 532 }
nuclear@14 533
nuclear@14 534 #endif /* D_MULTISCAN_FILES_SUPPORTED */
nuclear@14 535
nuclear@14 536
nuclear@14 537 /*
nuclear@14 538 * Initialize master decompression control and select active modules.
nuclear@14 539 * This is performed at the start of jpeg_start_decompress.
nuclear@14 540 */
nuclear@14 541
nuclear@14 542 GLOBAL(void)
nuclear@14 543 jinit_master_decompress (j_decompress_ptr cinfo)
nuclear@14 544 {
nuclear@14 545 my_master_ptr master;
nuclear@14 546
nuclear@14 547 master = (my_master_ptr)
nuclear@14 548 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 549 SIZEOF(my_decomp_master));
nuclear@14 550 cinfo->master = (struct jpeg_decomp_master *) master;
nuclear@14 551 master->pub.prepare_for_output_pass = prepare_for_output_pass;
nuclear@14 552 master->pub.finish_output_pass = finish_output_pass;
nuclear@14 553
nuclear@14 554 master->pub.is_dummy_pass = FALSE;
nuclear@14 555
nuclear@14 556 master_selection(cinfo);
nuclear@14 557 }