jdmaster.c (34487B)
1 /* 2 * jdmaster.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * Modified 2002-2009 by Guido Vollbeding. 7 * Lossless JPEG Modifications: 8 * Copyright (C) 1999, Ken Murchison. 9 * libjpeg-turbo Modifications: 10 * Copyright (C) 2009-2011, 2016, 2019, 2022-2023, D. R. Commander. 11 * Copyright (C) 2013, Linaro Limited. 12 * Copyright (C) 2015, Google, Inc. 13 * For conditions of distribution and use, see the accompanying README.ijg 14 * file. 15 * 16 * This file contains master control logic for the JPEG decompressor. 17 * These routines are concerned with selecting the modules to be executed 18 * and with determining the number of passes and the work to be done in each 19 * pass. 20 */ 21 22 #define JPEG_INTERNALS 23 #include "jinclude.h" 24 #include "jpeglib.h" 25 #include "jpegapicomp.h" 26 #include "jdmaster.h" 27 28 29 /* 30 * Determine whether merged upsample/color conversion should be used. 31 * CRUCIAL: this must match the actual capabilities of jdmerge.c! 32 */ 33 34 LOCAL(boolean) 35 use_merged_upsample(j_decompress_ptr cinfo) 36 { 37 #ifdef UPSAMPLE_MERGING_SUPPORTED 38 /* Colorspace conversion is not supported with lossless JPEG images */ 39 if (cinfo->master->lossless) 40 return FALSE; 41 /* Merging is the equivalent of plain box-filter upsampling */ 42 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) 43 return FALSE; 44 /* jdmerge.c only supports YCC=>RGB and YCC=>RGB565 color conversion */ 45 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 || 46 (cinfo->out_color_space != JCS_RGB && 47 cinfo->out_color_space != JCS_RGB565 && 48 cinfo->out_color_space != JCS_EXT_RGB && 49 cinfo->out_color_space != JCS_EXT_RGBX && 50 cinfo->out_color_space != JCS_EXT_BGR && 51 cinfo->out_color_space != JCS_EXT_BGRX && 52 cinfo->out_color_space != JCS_EXT_XBGR && 53 cinfo->out_color_space != JCS_EXT_XRGB && 54 cinfo->out_color_space != JCS_EXT_RGBA && 55 cinfo->out_color_space != JCS_EXT_BGRA && 56 cinfo->out_color_space != JCS_EXT_ABGR && 57 cinfo->out_color_space != JCS_EXT_ARGB)) 58 return FALSE; 59 if ((cinfo->out_color_space == JCS_RGB565 && 60 cinfo->out_color_components != 3) || 61 (cinfo->out_color_space != JCS_RGB565 && 62 cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space])) 63 return FALSE; 64 /* and it only handles 2h1v or 2h2v sampling ratios */ 65 if (cinfo->comp_info[0].h_samp_factor != 2 || 66 cinfo->comp_info[1].h_samp_factor != 1 || 67 cinfo->comp_info[2].h_samp_factor != 1 || 68 cinfo->comp_info[0].v_samp_factor > 2 || 69 cinfo->comp_info[1].v_samp_factor != 1 || 70 cinfo->comp_info[2].v_samp_factor != 1) 71 return FALSE; 72 /* furthermore, it doesn't work if we've scaled the IDCTs differently */ 73 if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 74 cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 75 cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size) 76 return FALSE; 77 /* ??? also need to test for upsample-time rescaling, when & if supported */ 78 return TRUE; /* by golly, it'll work... */ 79 #else 80 return FALSE; 81 #endif 82 } 83 84 85 /* 86 * Compute output image dimensions and related values. 87 * NOTE: this is exported for possible use by application. 88 * Hence it mustn't do anything that can't be done twice. 89 */ 90 91 #if JPEG_LIB_VERSION >= 80 92 GLOBAL(void) 93 #else 94 LOCAL(void) 95 #endif 96 jpeg_core_output_dimensions(j_decompress_ptr cinfo) 97 /* Do computations that are needed before master selection phase. 98 * This function is used for transcoding and full decompression. 99 */ 100 { 101 #ifdef IDCT_SCALING_SUPPORTED 102 int ci; 103 jpeg_component_info *compptr; 104 105 if (!cinfo->master->lossless) { 106 /* Compute actual output image dimensions and DCT scaling choices. */ 107 if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) { 108 /* Provide 1/block_size scaling */ 109 cinfo->output_width = (JDIMENSION) 110 jdiv_round_up((long)cinfo->image_width, (long)DCTSIZE); 111 cinfo->output_height = (JDIMENSION) 112 jdiv_round_up((long)cinfo->image_height, (long)DCTSIZE); 113 cinfo->_min_DCT_h_scaled_size = 1; 114 cinfo->_min_DCT_v_scaled_size = 1; 115 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) { 116 /* Provide 2/block_size scaling */ 117 cinfo->output_width = (JDIMENSION) 118 jdiv_round_up((long)cinfo->image_width * 2L, (long)DCTSIZE); 119 cinfo->output_height = (JDIMENSION) 120 jdiv_round_up((long)cinfo->image_height * 2L, (long)DCTSIZE); 121 cinfo->_min_DCT_h_scaled_size = 2; 122 cinfo->_min_DCT_v_scaled_size = 2; 123 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) { 124 /* Provide 3/block_size scaling */ 125 cinfo->output_width = (JDIMENSION) 126 jdiv_round_up((long)cinfo->image_width * 3L, (long)DCTSIZE); 127 cinfo->output_height = (JDIMENSION) 128 jdiv_round_up((long)cinfo->image_height * 3L, (long)DCTSIZE); 129 cinfo->_min_DCT_h_scaled_size = 3; 130 cinfo->_min_DCT_v_scaled_size = 3; 131 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) { 132 /* Provide 4/block_size scaling */ 133 cinfo->output_width = (JDIMENSION) 134 jdiv_round_up((long)cinfo->image_width * 4L, (long)DCTSIZE); 135 cinfo->output_height = (JDIMENSION) 136 jdiv_round_up((long)cinfo->image_height * 4L, (long)DCTSIZE); 137 cinfo->_min_DCT_h_scaled_size = 4; 138 cinfo->_min_DCT_v_scaled_size = 4; 139 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) { 140 /* Provide 5/block_size scaling */ 141 cinfo->output_width = (JDIMENSION) 142 jdiv_round_up((long)cinfo->image_width * 5L, (long)DCTSIZE); 143 cinfo->output_height = (JDIMENSION) 144 jdiv_round_up((long)cinfo->image_height * 5L, (long)DCTSIZE); 145 cinfo->_min_DCT_h_scaled_size = 5; 146 cinfo->_min_DCT_v_scaled_size = 5; 147 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) { 148 /* Provide 6/block_size scaling */ 149 cinfo->output_width = (JDIMENSION) 150 jdiv_round_up((long)cinfo->image_width * 6L, (long)DCTSIZE); 151 cinfo->output_height = (JDIMENSION) 152 jdiv_round_up((long)cinfo->image_height * 6L, (long)DCTSIZE); 153 cinfo->_min_DCT_h_scaled_size = 6; 154 cinfo->_min_DCT_v_scaled_size = 6; 155 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) { 156 /* Provide 7/block_size scaling */ 157 cinfo->output_width = (JDIMENSION) 158 jdiv_round_up((long)cinfo->image_width * 7L, (long)DCTSIZE); 159 cinfo->output_height = (JDIMENSION) 160 jdiv_round_up((long)cinfo->image_height * 7L, (long)DCTSIZE); 161 cinfo->_min_DCT_h_scaled_size = 7; 162 cinfo->_min_DCT_v_scaled_size = 7; 163 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) { 164 /* Provide 8/block_size scaling */ 165 cinfo->output_width = (JDIMENSION) 166 jdiv_round_up((long)cinfo->image_width * 8L, (long)DCTSIZE); 167 cinfo->output_height = (JDIMENSION) 168 jdiv_round_up((long)cinfo->image_height * 8L, (long)DCTSIZE); 169 cinfo->_min_DCT_h_scaled_size = 8; 170 cinfo->_min_DCT_v_scaled_size = 8; 171 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) { 172 /* Provide 9/block_size scaling */ 173 cinfo->output_width = (JDIMENSION) 174 jdiv_round_up((long)cinfo->image_width * 9L, (long)DCTSIZE); 175 cinfo->output_height = (JDIMENSION) 176 jdiv_round_up((long)cinfo->image_height * 9L, (long)DCTSIZE); 177 cinfo->_min_DCT_h_scaled_size = 9; 178 cinfo->_min_DCT_v_scaled_size = 9; 179 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) { 180 /* Provide 10/block_size scaling */ 181 cinfo->output_width = (JDIMENSION) 182 jdiv_round_up((long)cinfo->image_width * 10L, (long)DCTSIZE); 183 cinfo->output_height = (JDIMENSION) 184 jdiv_round_up((long)cinfo->image_height * 10L, (long)DCTSIZE); 185 cinfo->_min_DCT_h_scaled_size = 10; 186 cinfo->_min_DCT_v_scaled_size = 10; 187 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) { 188 /* Provide 11/block_size scaling */ 189 cinfo->output_width = (JDIMENSION) 190 jdiv_round_up((long)cinfo->image_width * 11L, (long)DCTSIZE); 191 cinfo->output_height = (JDIMENSION) 192 jdiv_round_up((long)cinfo->image_height * 11L, (long)DCTSIZE); 193 cinfo->_min_DCT_h_scaled_size = 11; 194 cinfo->_min_DCT_v_scaled_size = 11; 195 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) { 196 /* Provide 12/block_size scaling */ 197 cinfo->output_width = (JDIMENSION) 198 jdiv_round_up((long)cinfo->image_width * 12L, (long)DCTSIZE); 199 cinfo->output_height = (JDIMENSION) 200 jdiv_round_up((long)cinfo->image_height * 12L, (long)DCTSIZE); 201 cinfo->_min_DCT_h_scaled_size = 12; 202 cinfo->_min_DCT_v_scaled_size = 12; 203 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) { 204 /* Provide 13/block_size scaling */ 205 cinfo->output_width = (JDIMENSION) 206 jdiv_round_up((long)cinfo->image_width * 13L, (long)DCTSIZE); 207 cinfo->output_height = (JDIMENSION) 208 jdiv_round_up((long)cinfo->image_height * 13L, (long)DCTSIZE); 209 cinfo->_min_DCT_h_scaled_size = 13; 210 cinfo->_min_DCT_v_scaled_size = 13; 211 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) { 212 /* Provide 14/block_size scaling */ 213 cinfo->output_width = (JDIMENSION) 214 jdiv_round_up((long)cinfo->image_width * 14L, (long)DCTSIZE); 215 cinfo->output_height = (JDIMENSION) 216 jdiv_round_up((long)cinfo->image_height * 14L, (long)DCTSIZE); 217 cinfo->_min_DCT_h_scaled_size = 14; 218 cinfo->_min_DCT_v_scaled_size = 14; 219 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) { 220 /* Provide 15/block_size scaling */ 221 cinfo->output_width = (JDIMENSION) 222 jdiv_round_up((long)cinfo->image_width * 15L, (long)DCTSIZE); 223 cinfo->output_height = (JDIMENSION) 224 jdiv_round_up((long)cinfo->image_height * 15L, (long)DCTSIZE); 225 cinfo->_min_DCT_h_scaled_size = 15; 226 cinfo->_min_DCT_v_scaled_size = 15; 227 } else { 228 /* Provide 16/block_size scaling */ 229 cinfo->output_width = (JDIMENSION) 230 jdiv_round_up((long)cinfo->image_width * 16L, (long)DCTSIZE); 231 cinfo->output_height = (JDIMENSION) 232 jdiv_round_up((long)cinfo->image_height * 16L, (long)DCTSIZE); 233 cinfo->_min_DCT_h_scaled_size = 16; 234 cinfo->_min_DCT_v_scaled_size = 16; 235 } 236 237 /* Recompute dimensions of components */ 238 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 239 ci++, compptr++) { 240 compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size; 241 compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size; 242 } 243 } else 244 #endif /* !IDCT_SCALING_SUPPORTED */ 245 { 246 /* Hardwire it to "no scaling" */ 247 cinfo->output_width = cinfo->image_width; 248 cinfo->output_height = cinfo->image_height; 249 /* jdinput.c has already initialized DCT_scaled_size, 250 * and has computed unscaled downsampled_width and downsampled_height. 251 */ 252 } 253 } 254 255 256 /* 257 * Compute output image dimensions and related values. 258 * NOTE: this is exported for possible use by application. 259 * Hence it mustn't do anything that can't be done twice. 260 * Also note that it may be called before the master module is initialized! 261 */ 262 263 GLOBAL(void) 264 jpeg_calc_output_dimensions(j_decompress_ptr cinfo) 265 /* Do computations that are needed before master selection phase */ 266 { 267 #ifdef IDCT_SCALING_SUPPORTED 268 int ci; 269 jpeg_component_info *compptr; 270 #endif 271 272 /* Prevent application from calling me at wrong times */ 273 if (cinfo->global_state != DSTATE_READY) 274 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 275 276 /* Compute core output image dimensions and DCT scaling choices. */ 277 jpeg_core_output_dimensions(cinfo); 278 279 #ifdef IDCT_SCALING_SUPPORTED 280 281 if (!cinfo->master->lossless) { 282 /* In selecting the actual DCT scaling for each component, we try to 283 * scale up the chroma components via IDCT scaling rather than upsampling. 284 * This saves time if the upsampler gets to use 1:1 scaling. 285 * Note this code adapts subsampling ratios which are powers of 2. 286 */ 287 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 288 ci++, compptr++) { 289 int ssize = cinfo->_min_DCT_scaled_size; 290 while (ssize < DCTSIZE && 291 ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) % 292 (compptr->h_samp_factor * ssize * 2) == 0) && 293 ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) % 294 (compptr->v_samp_factor * ssize * 2) == 0)) { 295 ssize = ssize * 2; 296 } 297 #if JPEG_LIB_VERSION >= 70 298 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize; 299 #else 300 compptr->DCT_scaled_size = ssize; 301 #endif 302 } 303 304 /* Recompute downsampled dimensions of components; 305 * application needs to know these if using raw downsampled data. 306 */ 307 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 308 ci++, compptr++) { 309 /* Size in samples, after IDCT scaling */ 310 compptr->downsampled_width = (JDIMENSION) 311 jdiv_round_up((long)cinfo->image_width * 312 (long)(compptr->h_samp_factor * 313 compptr->_DCT_scaled_size), 314 (long)(cinfo->max_h_samp_factor * DCTSIZE)); 315 compptr->downsampled_height = (JDIMENSION) 316 jdiv_round_up((long)cinfo->image_height * 317 (long)(compptr->v_samp_factor * 318 compptr->_DCT_scaled_size), 319 (long)(cinfo->max_v_samp_factor * DCTSIZE)); 320 } 321 } else 322 #endif /* IDCT_SCALING_SUPPORTED */ 323 { 324 /* Hardwire it to "no scaling" */ 325 cinfo->output_width = cinfo->image_width; 326 cinfo->output_height = cinfo->image_height; 327 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE, 328 * and has computed unscaled downsampled_width and downsampled_height. 329 */ 330 } 331 332 /* Report number of components in selected colorspace. */ 333 /* Probably this should be in the color conversion module... */ 334 switch (cinfo->out_color_space) { 335 case JCS_GRAYSCALE: 336 cinfo->out_color_components = 1; 337 break; 338 case JCS_RGB: 339 case JCS_EXT_RGB: 340 case JCS_EXT_RGBX: 341 case JCS_EXT_BGR: 342 case JCS_EXT_BGRX: 343 case JCS_EXT_XBGR: 344 case JCS_EXT_XRGB: 345 case JCS_EXT_RGBA: 346 case JCS_EXT_BGRA: 347 case JCS_EXT_ABGR: 348 case JCS_EXT_ARGB: 349 cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space]; 350 break; 351 case JCS_YCbCr: 352 case JCS_RGB565: 353 cinfo->out_color_components = 3; 354 break; 355 case JCS_CMYK: 356 case JCS_YCCK: 357 cinfo->out_color_components = 4; 358 break; 359 default: /* else must be same colorspace as in file */ 360 cinfo->out_color_components = cinfo->num_components; 361 break; 362 } 363 cinfo->output_components = (cinfo->quantize_colors ? 1 : 364 cinfo->out_color_components); 365 366 /* See if upsampler will want to emit more than one row at a time */ 367 if (use_merged_upsample(cinfo)) 368 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor; 369 else 370 cinfo->rec_outbuf_height = 1; 371 } 372 373 374 /* 375 * Several decompression processes need to range-limit values to the range 376 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range 377 * due to noise introduced by quantization, roundoff error, etc. These 378 * processes are inner loops and need to be as fast as possible. On most 379 * machines, particularly CPUs with pipelines or instruction prefetch, 380 * a (subscript-check-less) C table lookup 381 * x = sample_range_limit[x]; 382 * is faster than explicit tests 383 * if (x < 0) x = 0; 384 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE; 385 * These processes all use a common table prepared by the routine below. 386 * 387 * For most steps we can mathematically guarantee that the initial value 388 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from 389 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial 390 * limiting step (just after the IDCT), a wildly out-of-range value is 391 * possible if the input data is corrupt. To avoid any chance of indexing 392 * off the end of memory and getting a bad-pointer trap, we perform the 393 * post-IDCT limiting thus: 394 * x = range_limit[x & MASK]; 395 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit 396 * samples. Under normal circumstances this is more than enough range and 397 * a correct output will be generated; with bogus input data the mask will 398 * cause wraparound, and we will safely generate a bogus-but-in-range output. 399 * For the post-IDCT step, we want to convert the data from signed to unsigned 400 * representation by adding CENTERJSAMPLE at the same time that we limit it. 401 * So the post-IDCT limiting table ends up looking like this: 402 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE, 403 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 404 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 405 * 0,1,...,CENTERJSAMPLE-1 406 * Negative inputs select values from the upper half of the table after 407 * masking. 408 * 409 * We can save some space by overlapping the start of the post-IDCT table 410 * with the simpler range limiting table. The post-IDCT table begins at 411 * sample_range_limit + CENTERJSAMPLE. 412 */ 413 414 LOCAL(void) 415 prepare_range_limit_table(j_decompress_ptr cinfo) 416 /* Allocate and fill in the sample_range_limit table */ 417 { 418 JSAMPLE *table; 419 J12SAMPLE *table12; 420 #ifdef D_LOSSLESS_SUPPORTED 421 J16SAMPLE *table16; 422 #endif 423 int i; 424 425 if (cinfo->data_precision == 16) { 426 #ifdef D_LOSSLESS_SUPPORTED 427 table16 = (J16SAMPLE *) 428 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, 429 (5 * (MAXJ16SAMPLE + 1) + CENTERJ16SAMPLE) * 430 sizeof(J16SAMPLE)); 431 table16 += (MAXJ16SAMPLE + 1); /* allow negative subscripts of simple 432 table */ 433 cinfo->sample_range_limit = (JSAMPLE *)table16; 434 /* First segment of "simple" table: limit[x] = 0 for x < 0 */ 435 memset(table16 - (MAXJ16SAMPLE + 1), 0, 436 (MAXJ16SAMPLE + 1) * sizeof(J16SAMPLE)); 437 /* Main part of "simple" table: limit[x] = x */ 438 for (i = 0; i <= MAXJ16SAMPLE; i++) 439 table16[i] = (J16SAMPLE)i; 440 table16 += CENTERJ16SAMPLE; /* Point to where post-IDCT table starts */ 441 /* End of simple table, rest of first half of post-IDCT table */ 442 for (i = CENTERJ16SAMPLE; i < 2 * (MAXJ16SAMPLE + 1); i++) 443 table16[i] = MAXJ16SAMPLE; 444 /* Second half of post-IDCT table */ 445 memset(table16 + (2 * (MAXJ16SAMPLE + 1)), 0, 446 (2 * (MAXJ16SAMPLE + 1) - CENTERJ16SAMPLE) * sizeof(J16SAMPLE)); 447 memcpy(table16 + (4 * (MAXJ16SAMPLE + 1) - CENTERJ16SAMPLE), 448 cinfo->sample_range_limit, CENTERJ16SAMPLE * sizeof(J16SAMPLE)); 449 #else 450 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 451 #endif 452 } else if (cinfo->data_precision == 12) { 453 table12 = (J12SAMPLE *) 454 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, 455 (5 * (MAXJ12SAMPLE + 1) + CENTERJ12SAMPLE) * 456 sizeof(J12SAMPLE)); 457 table12 += (MAXJ12SAMPLE + 1); /* allow negative subscripts of simple 458 table */ 459 cinfo->sample_range_limit = (JSAMPLE *)table12; 460 /* First segment of "simple" table: limit[x] = 0 for x < 0 */ 461 memset(table12 - (MAXJ12SAMPLE + 1), 0, 462 (MAXJ12SAMPLE + 1) * sizeof(J12SAMPLE)); 463 /* Main part of "simple" table: limit[x] = x */ 464 for (i = 0; i <= MAXJ12SAMPLE; i++) 465 table12[i] = (J12SAMPLE)i; 466 table12 += CENTERJ12SAMPLE; /* Point to where post-IDCT table starts */ 467 /* End of simple table, rest of first half of post-IDCT table */ 468 for (i = CENTERJ12SAMPLE; i < 2 * (MAXJ12SAMPLE + 1); i++) 469 table12[i] = MAXJ12SAMPLE; 470 /* Second half of post-IDCT table */ 471 memset(table12 + (2 * (MAXJ12SAMPLE + 1)), 0, 472 (2 * (MAXJ12SAMPLE + 1) - CENTERJ12SAMPLE) * sizeof(J12SAMPLE)); 473 memcpy(table12 + (4 * (MAXJ12SAMPLE + 1) - CENTERJ12SAMPLE), 474 cinfo->sample_range_limit, CENTERJ12SAMPLE * sizeof(J12SAMPLE)); 475 } else { 476 table = (JSAMPLE *) 477 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, 478 (5 * (MAXJSAMPLE + 1) + CENTERJSAMPLE) * sizeof(JSAMPLE)); 479 table += (MAXJSAMPLE + 1); /* allow negative subscripts of simple table */ 480 cinfo->sample_range_limit = table; 481 /* First segment of "simple" table: limit[x] = 0 for x < 0 */ 482 memset(table - (MAXJSAMPLE + 1), 0, (MAXJSAMPLE + 1) * sizeof(JSAMPLE)); 483 /* Main part of "simple" table: limit[x] = x */ 484 for (i = 0; i <= MAXJSAMPLE; i++) 485 table[i] = (JSAMPLE)i; 486 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */ 487 /* End of simple table, rest of first half of post-IDCT table */ 488 for (i = CENTERJSAMPLE; i < 2 * (MAXJSAMPLE + 1); i++) 489 table[i] = MAXJSAMPLE; 490 /* Second half of post-IDCT table */ 491 memset(table + (2 * (MAXJSAMPLE + 1)), 0, 492 (2 * (MAXJSAMPLE + 1) - CENTERJSAMPLE) * sizeof(JSAMPLE)); 493 memcpy(table + (4 * (MAXJSAMPLE + 1) - CENTERJSAMPLE), 494 cinfo->sample_range_limit, CENTERJSAMPLE * sizeof(JSAMPLE)); 495 } 496 } 497 498 499 /* 500 * Master selection of decompression modules. 501 * This is done once at jpeg_start_decompress time. We determine 502 * which modules will be used and give them appropriate initialization calls. 503 * We also initialize the decompressor input side to begin consuming data. 504 * 505 * Since jpeg_read_header has finished, we know what is in the SOF 506 * and (first) SOS markers. We also have all the application parameter 507 * settings. 508 */ 509 510 LOCAL(void) 511 master_selection(j_decompress_ptr cinfo) 512 { 513 my_master_ptr master = (my_master_ptr)cinfo->master; 514 boolean use_c_buffer; 515 long samplesperrow; 516 JDIMENSION jd_samplesperrow; 517 518 /* Disable IDCT scaling and raw (downsampled) data output in lossless mode. 519 * IDCT scaling is not useful in lossless mode, and it must be disabled in 520 * order to properly calculate the output dimensions. Raw data output isn't 521 * particularly useful without subsampling and has not been tested in 522 * lossless mode. 523 */ 524 if (cinfo->master->lossless) { 525 cinfo->raw_data_out = FALSE; 526 cinfo->scale_num = cinfo->scale_denom = 1; 527 } 528 529 /* Initialize dimensions and other stuff */ 530 jpeg_calc_output_dimensions(cinfo); 531 prepare_range_limit_table(cinfo); 532 533 /* Width of an output scanline must be representable as JDIMENSION. */ 534 samplesperrow = (long)cinfo->output_width * 535 (long)cinfo->out_color_components; 536 jd_samplesperrow = (JDIMENSION)samplesperrow; 537 if ((long)jd_samplesperrow != samplesperrow) 538 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 539 540 /* Initialize my private state */ 541 master->pass_number = 0; 542 master->using_merged_upsample = use_merged_upsample(cinfo); 543 544 /* Color quantizer selection */ 545 master->quantizer_1pass = NULL; 546 master->quantizer_2pass = NULL; 547 /* No mode changes if not using buffered-image mode. */ 548 if (!cinfo->quantize_colors || !cinfo->buffered_image) { 549 cinfo->enable_1pass_quant = FALSE; 550 cinfo->enable_external_quant = FALSE; 551 cinfo->enable_2pass_quant = FALSE; 552 } 553 if (cinfo->quantize_colors) { 554 if (cinfo->raw_data_out) 555 ERREXIT(cinfo, JERR_NOTIMPL); 556 /* 2-pass quantizer only works in 3-component color space. */ 557 if (cinfo->out_color_components != 3 || 558 cinfo->out_color_space == JCS_RGB565) { 559 cinfo->enable_1pass_quant = TRUE; 560 cinfo->enable_external_quant = FALSE; 561 cinfo->enable_2pass_quant = FALSE; 562 cinfo->colormap = NULL; 563 } else if (cinfo->colormap != NULL) { 564 cinfo->enable_external_quant = TRUE; 565 } else if (cinfo->two_pass_quantize) { 566 cinfo->enable_2pass_quant = TRUE; 567 } else { 568 cinfo->enable_1pass_quant = TRUE; 569 } 570 571 if (cinfo->enable_1pass_quant) { 572 #ifdef QUANT_1PASS_SUPPORTED 573 if (cinfo->data_precision == 16) 574 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 575 else if (cinfo->data_precision == 12) 576 j12init_1pass_quantizer(cinfo); 577 else 578 jinit_1pass_quantizer(cinfo); 579 master->quantizer_1pass = cinfo->cquantize; 580 #else 581 ERREXIT(cinfo, JERR_NOT_COMPILED); 582 #endif 583 } 584 585 /* We use the 2-pass code to map to external colormaps. */ 586 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) { 587 #ifdef QUANT_2PASS_SUPPORTED 588 if (cinfo->data_precision == 16) 589 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 590 else if (cinfo->data_precision == 12) 591 j12init_2pass_quantizer(cinfo); 592 else 593 jinit_2pass_quantizer(cinfo); 594 master->quantizer_2pass = cinfo->cquantize; 595 #else 596 ERREXIT(cinfo, JERR_NOT_COMPILED); 597 #endif 598 } 599 /* If both quantizers are initialized, the 2-pass one is left active; 600 * this is necessary for starting with quantization to an external map. 601 */ 602 } 603 604 /* Post-processing: in particular, color conversion first */ 605 if (!cinfo->raw_data_out) { 606 if (master->using_merged_upsample) { 607 #ifdef UPSAMPLE_MERGING_SUPPORTED 608 if (cinfo->data_precision == 16) 609 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 610 else if (cinfo->data_precision == 12) 611 j12init_merged_upsampler(cinfo); /* does color conversion too */ 612 else 613 jinit_merged_upsampler(cinfo); /* does color conversion too */ 614 #else 615 ERREXIT(cinfo, JERR_NOT_COMPILED); 616 #endif 617 } else { 618 if (cinfo->data_precision == 16) { 619 #ifdef D_LOSSLESS_SUPPORTED 620 j16init_color_deconverter(cinfo); 621 j16init_upsampler(cinfo); 622 #else 623 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 624 #endif 625 } else if (cinfo->data_precision == 12) { 626 j12init_color_deconverter(cinfo); 627 j12init_upsampler(cinfo); 628 } else { 629 jinit_color_deconverter(cinfo); 630 jinit_upsampler(cinfo); 631 } 632 } 633 if (cinfo->data_precision == 16) 634 #ifdef D_LOSSLESS_SUPPORTED 635 j16init_d_post_controller(cinfo, cinfo->enable_2pass_quant); 636 #else 637 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 638 #endif 639 else if (cinfo->data_precision == 12) 640 j12init_d_post_controller(cinfo, cinfo->enable_2pass_quant); 641 else 642 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant); 643 } 644 645 if (cinfo->master->lossless) { 646 #ifdef D_LOSSLESS_SUPPORTED 647 /* Prediction, sample undifferencing, point transform, and sample size 648 * scaling 649 */ 650 if (cinfo->data_precision == 16) 651 j16init_lossless_decompressor(cinfo); 652 else if (cinfo->data_precision == 12) 653 j12init_lossless_decompressor(cinfo); 654 else 655 jinit_lossless_decompressor(cinfo); 656 /* Entropy decoding: either Huffman or arithmetic coding. */ 657 if (cinfo->arith_code) { 658 ERREXIT(cinfo, JERR_ARITH_NOTIMPL); 659 } else { 660 jinit_lhuff_decoder(cinfo); 661 } 662 663 /* Initialize principal buffer controllers. */ 664 use_c_buffer = cinfo->inputctl->has_multiple_scans || 665 cinfo->buffered_image; 666 if (cinfo->data_precision == 16) 667 j16init_d_diff_controller(cinfo, use_c_buffer); 668 else if (cinfo->data_precision == 12) 669 j12init_d_diff_controller(cinfo, use_c_buffer); 670 else 671 jinit_d_diff_controller(cinfo, use_c_buffer); 672 #else 673 ERREXIT(cinfo, JERR_NOT_COMPILED); 674 #endif 675 } else { 676 if (cinfo->data_precision == 16) 677 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 678 /* Inverse DCT */ 679 if (cinfo->data_precision == 12) 680 j12init_inverse_dct(cinfo); 681 else 682 jinit_inverse_dct(cinfo); 683 /* Entropy decoding: either Huffman or arithmetic coding. */ 684 if (cinfo->arith_code) { 685 #ifdef D_ARITH_CODING_SUPPORTED 686 jinit_arith_decoder(cinfo); 687 #else 688 ERREXIT(cinfo, JERR_ARITH_NOTIMPL); 689 #endif 690 } else { 691 if (cinfo->progressive_mode) { 692 #ifdef D_PROGRESSIVE_SUPPORTED 693 jinit_phuff_decoder(cinfo); 694 #else 695 ERREXIT(cinfo, JERR_NOT_COMPILED); 696 #endif 697 } else 698 jinit_huff_decoder(cinfo); 699 } 700 701 /* Initialize principal buffer controllers. */ 702 use_c_buffer = cinfo->inputctl->has_multiple_scans || 703 cinfo->buffered_image; 704 if (cinfo->data_precision == 12) 705 j12init_d_coef_controller(cinfo, use_c_buffer); 706 else 707 jinit_d_coef_controller(cinfo, use_c_buffer); 708 } 709 710 if (!cinfo->raw_data_out) { 711 if (cinfo->data_precision == 16) 712 #ifdef D_LOSSLESS_SUPPORTED 713 j16init_d_main_controller(cinfo, 714 FALSE /* never need full buffer here */); 715 #else 716 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 717 #endif 718 else if (cinfo->data_precision == 12) 719 j12init_d_main_controller(cinfo, 720 FALSE /* never need full buffer here */); 721 else 722 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */); 723 } 724 725 /* We can now tell the memory manager to allocate virtual arrays. */ 726 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr)cinfo); 727 728 /* Initialize input side of decompressor to consume first scan. */ 729 (*cinfo->inputctl->start_input_pass) (cinfo); 730 731 /* Set the first and last iMCU columns to decompress from single-scan images. 732 * By default, decompress all of the iMCU columns. 733 */ 734 cinfo->master->first_iMCU_col = 0; 735 cinfo->master->last_iMCU_col = cinfo->MCUs_per_row - 1; 736 cinfo->master->last_good_iMCU_row = 0; 737 738 #ifdef D_MULTISCAN_FILES_SUPPORTED 739 /* If jpeg_start_decompress will read the whole file, initialize 740 * progress monitoring appropriately. The input step is counted 741 * as one pass. 742 */ 743 if (cinfo->progress != NULL && !cinfo->buffered_image && 744 cinfo->inputctl->has_multiple_scans) { 745 int nscans; 746 /* Estimate number of scans to set pass_limit. */ 747 if (cinfo->progressive_mode) { 748 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */ 749 nscans = 2 + 3 * cinfo->num_components; 750 } else { 751 /* For a nonprogressive multiscan file, estimate 1 scan per component. */ 752 nscans = cinfo->num_components; 753 } 754 cinfo->progress->pass_counter = 0L; 755 cinfo->progress->pass_limit = (long)cinfo->total_iMCU_rows * nscans; 756 cinfo->progress->completed_passes = 0; 757 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2); 758 /* Count the input pass as done */ 759 master->pass_number++; 760 } 761 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 762 } 763 764 765 /* 766 * Per-pass setup. 767 * This is called at the beginning of each output pass. We determine which 768 * modules will be active during this pass and give them appropriate 769 * start_pass calls. We also set is_dummy_pass to indicate whether this 770 * is a "real" output pass or a dummy pass for color quantization. 771 * (In the latter case, jdapistd.c will crank the pass to completion.) 772 */ 773 774 METHODDEF(void) 775 prepare_for_output_pass(j_decompress_ptr cinfo) 776 { 777 my_master_ptr master = (my_master_ptr)cinfo->master; 778 779 if (master->pub.is_dummy_pass) { 780 #ifdef QUANT_2PASS_SUPPORTED 781 /* Final pass of 2-pass quantization */ 782 master->pub.is_dummy_pass = FALSE; 783 (*cinfo->cquantize->start_pass) (cinfo, FALSE); 784 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST); 785 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST); 786 #else 787 ERREXIT(cinfo, JERR_NOT_COMPILED); 788 #endif /* QUANT_2PASS_SUPPORTED */ 789 } else { 790 if (cinfo->quantize_colors && cinfo->colormap == NULL) { 791 /* Select new quantization method */ 792 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) { 793 cinfo->cquantize = master->quantizer_2pass; 794 master->pub.is_dummy_pass = TRUE; 795 } else if (cinfo->enable_1pass_quant) { 796 cinfo->cquantize = master->quantizer_1pass; 797 } else { 798 ERREXIT(cinfo, JERR_MODE_CHANGE); 799 } 800 } 801 (*cinfo->idct->start_pass) (cinfo); 802 (*cinfo->coef->start_output_pass) (cinfo); 803 if (!cinfo->raw_data_out) { 804 if (!master->using_merged_upsample) 805 (*cinfo->cconvert->start_pass) (cinfo); 806 (*cinfo->upsample->start_pass) (cinfo); 807 if (cinfo->quantize_colors) 808 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass); 809 (*cinfo->post->start_pass) (cinfo, 810 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 811 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 812 } 813 } 814 815 /* Set up progress monitor's pass info if present */ 816 if (cinfo->progress != NULL) { 817 cinfo->progress->completed_passes = master->pass_number; 818 cinfo->progress->total_passes = master->pass_number + 819 (master->pub.is_dummy_pass ? 2 : 1); 820 /* In buffered-image mode, we assume one more output pass if EOI not 821 * yet reached, but no more passes if EOI has been reached. 822 */ 823 if (cinfo->buffered_image && !cinfo->inputctl->eoi_reached) { 824 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1); 825 } 826 } 827 } 828 829 830 /* 831 * Finish up at end of an output pass. 832 */ 833 834 METHODDEF(void) 835 finish_output_pass(j_decompress_ptr cinfo) 836 { 837 my_master_ptr master = (my_master_ptr)cinfo->master; 838 839 if (cinfo->quantize_colors) 840 (*cinfo->cquantize->finish_pass) (cinfo); 841 master->pass_number++; 842 } 843 844 845 #ifdef D_MULTISCAN_FILES_SUPPORTED 846 847 /* 848 * Switch to a new external colormap between output passes. 849 */ 850 851 GLOBAL(void) 852 jpeg_new_colormap(j_decompress_ptr cinfo) 853 { 854 my_master_ptr master = (my_master_ptr)cinfo->master; 855 856 /* Prevent application from calling me at wrong times */ 857 if (cinfo->global_state != DSTATE_BUFIMAGE) 858 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 859 860 if (cinfo->quantize_colors && cinfo->enable_external_quant && 861 cinfo->colormap != NULL) { 862 /* Select 2-pass quantizer for external colormap use */ 863 cinfo->cquantize = master->quantizer_2pass; 864 /* Notify quantizer of colormap change */ 865 (*cinfo->cquantize->new_color_map) (cinfo); 866 master->pub.is_dummy_pass = FALSE; /* just in case */ 867 } else 868 ERREXIT(cinfo, JERR_MODE_CHANGE); 869 } 870 871 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 872 873 874 /* 875 * Initialize master decompression control and select active modules. 876 * This is performed at the start of jpeg_start_decompress. 877 */ 878 879 GLOBAL(void) 880 jinit_master_decompress(j_decompress_ptr cinfo) 881 { 882 my_master_ptr master = (my_master_ptr)cinfo->master; 883 884 master->pub.prepare_for_output_pass = prepare_for_output_pass; 885 master->pub.finish_output_pass = finish_output_pass; 886 887 master->pub.is_dummy_pass = FALSE; 888 master->pub.jinit_upsampler_no_alloc = FALSE; 889 890 master_selection(cinfo); 891 }