jdinput.c (15069B)
1 /* 2 * jdinput.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * Lossless JPEG Modifications: 7 * Copyright (C) 1999, Ken Murchison. 8 * libjpeg-turbo Modifications: 9 * Copyright (C) 2010, 2016, 2018, 2022, D. R. Commander. 10 * Copyright (C) 2015, Google, Inc. 11 * For conditions of distribution and use, see the accompanying README.ijg 12 * file. 13 * 14 * This file contains input control logic for the JPEG decompressor. 15 * These routines are concerned with controlling the decompressor's input 16 * processing (marker reading and coefficient/difference decoding). 17 * The actual input reading is done in jdmarker.c, jdhuff.c, jdphuff.c, 18 * and jdlhuff.c. 19 */ 20 21 #define JPEG_INTERNALS 22 #include "jinclude.h" 23 #include "jpeglib.h" 24 #include "jpegapicomp.h" 25 26 27 /* Private state */ 28 29 typedef struct { 30 struct jpeg_input_controller pub; /* public fields */ 31 32 boolean inheaders; /* TRUE until first SOS is reached */ 33 } my_input_controller; 34 35 typedef my_input_controller *my_inputctl_ptr; 36 37 38 /* Forward declarations */ 39 METHODDEF(int) consume_markers(j_decompress_ptr cinfo); 40 41 42 /* 43 * Routines to calculate various quantities related to the size of the image. 44 */ 45 46 LOCAL(void) 47 initial_setup(j_decompress_ptr cinfo) 48 /* Called once, when first SOS marker is reached */ 49 { 50 int ci; 51 jpeg_component_info *compptr; 52 int data_unit = cinfo->master->lossless ? 1 : DCTSIZE; 53 54 /* Make sure image isn't bigger than I can handle */ 55 if ((long)cinfo->image_height > (long)JPEG_MAX_DIMENSION || 56 (long)cinfo->image_width > (long)JPEG_MAX_DIMENSION) 57 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)JPEG_MAX_DIMENSION); 58 59 /* For now, precision must match compiled-in value... */ 60 #ifdef D_LOSSLESS_SUPPORTED 61 if (cinfo->data_precision != 8 && cinfo->data_precision != 12 && 62 cinfo->data_precision != 16) 63 #else 64 if (cinfo->data_precision != 8 && cinfo->data_precision != 12) 65 #endif 66 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 67 68 /* Check that number of components won't exceed internal array sizes */ 69 if (cinfo->num_components > MAX_COMPONENTS) 70 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 71 MAX_COMPONENTS); 72 73 /* Compute maximum sampling factors; check factor validity */ 74 cinfo->max_h_samp_factor = 1; 75 cinfo->max_v_samp_factor = 1; 76 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 77 ci++, compptr++) { 78 if (compptr->h_samp_factor <= 0 || 79 compptr->h_samp_factor > MAX_SAMP_FACTOR || 80 compptr->v_samp_factor <= 0 || 81 compptr->v_samp_factor > MAX_SAMP_FACTOR) 82 ERREXIT(cinfo, JERR_BAD_SAMPLING); 83 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, 84 compptr->h_samp_factor); 85 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, 86 compptr->v_samp_factor); 87 } 88 89 #if JPEG_LIB_VERSION >= 80 90 cinfo->block_size = data_unit; 91 cinfo->natural_order = jpeg_natural_order; 92 cinfo->lim_Se = DCTSIZE2 - 1; 93 #endif 94 95 /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE in lossy 96 * mode. In the full decompressor, this will be overridden by jdmaster.c; 97 * but in the transcoder, jdmaster.c is not used, so we must do it here. 98 */ 99 #if JPEG_LIB_VERSION >= 70 100 cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = data_unit; 101 #else 102 cinfo->min_DCT_scaled_size = data_unit; 103 #endif 104 105 /* Compute dimensions of components */ 106 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 107 ci++, compptr++) { 108 #if JPEG_LIB_VERSION >= 70 109 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = data_unit; 110 #else 111 compptr->DCT_scaled_size = data_unit; 112 #endif 113 /* Size in data units */ 114 compptr->width_in_blocks = (JDIMENSION) 115 jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, 116 (long)(cinfo->max_h_samp_factor * data_unit)); 117 compptr->height_in_blocks = (JDIMENSION) 118 jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, 119 (long)(cinfo->max_v_samp_factor * data_unit)); 120 /* Set the first and last MCU columns to decompress from multi-scan images. 121 * By default, decompress all of the MCU columns. 122 */ 123 cinfo->master->first_MCU_col[ci] = 0; 124 cinfo->master->last_MCU_col[ci] = compptr->width_in_blocks - 1; 125 /* downsampled_width and downsampled_height will also be overridden by 126 * jdmaster.c if we are doing full decompression. The transcoder library 127 * doesn't use these values, but the calling application might. 128 */ 129 /* Size in samples */ 130 compptr->downsampled_width = (JDIMENSION) 131 jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, 132 (long)cinfo->max_h_samp_factor); 133 compptr->downsampled_height = (JDIMENSION) 134 jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, 135 (long)cinfo->max_v_samp_factor); 136 /* Mark component needed, until color conversion says otherwise */ 137 compptr->component_needed = TRUE; 138 /* Mark no quantization table yet saved for component */ 139 compptr->quant_table = NULL; 140 } 141 142 /* Compute number of fully interleaved MCU rows. */ 143 cinfo->total_iMCU_rows = (JDIMENSION) 144 jdiv_round_up((long)cinfo->image_height, 145 (long)(cinfo->max_v_samp_factor * data_unit)); 146 147 /* Decide whether file contains multiple scans */ 148 if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode) 149 cinfo->inputctl->has_multiple_scans = TRUE; 150 else 151 cinfo->inputctl->has_multiple_scans = FALSE; 152 } 153 154 155 LOCAL(void) 156 per_scan_setup(j_decompress_ptr cinfo) 157 /* Do computations that are needed before processing a JPEG scan */ 158 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */ 159 { 160 int ci, mcublks, tmp; 161 jpeg_component_info *compptr; 162 int data_unit = cinfo->master->lossless ? 1 : DCTSIZE; 163 164 if (cinfo->comps_in_scan == 1) { 165 166 /* Noninterleaved (single-component) scan */ 167 compptr = cinfo->cur_comp_info[0]; 168 169 /* Overall image size in MCUs */ 170 cinfo->MCUs_per_row = compptr->width_in_blocks; 171 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; 172 173 /* For noninterleaved scan, always one data unit per MCU */ 174 compptr->MCU_width = 1; 175 compptr->MCU_height = 1; 176 compptr->MCU_blocks = 1; 177 compptr->MCU_sample_width = compptr->_DCT_scaled_size; 178 compptr->last_col_width = 1; 179 /* For noninterleaved scans, it is convenient to define last_row_height 180 * as the number of data unit rows present in the last iMCU row. 181 */ 182 tmp = (int)(compptr->height_in_blocks % compptr->v_samp_factor); 183 if (tmp == 0) tmp = compptr->v_samp_factor; 184 compptr->last_row_height = tmp; 185 186 /* Prepare array describing MCU composition */ 187 cinfo->blocks_in_MCU = 1; 188 cinfo->MCU_membership[0] = 0; 189 190 } else { 191 192 /* Interleaved (multi-component) scan */ 193 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) 194 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, 195 MAX_COMPS_IN_SCAN); 196 197 /* Overall image size in MCUs */ 198 cinfo->MCUs_per_row = (JDIMENSION) 199 jdiv_round_up((long)cinfo->image_width, 200 (long)(cinfo->max_h_samp_factor * data_unit)); 201 cinfo->MCU_rows_in_scan = (JDIMENSION) 202 jdiv_round_up((long)cinfo->image_height, 203 (long)(cinfo->max_v_samp_factor * data_unit)); 204 205 cinfo->blocks_in_MCU = 0; 206 207 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 208 compptr = cinfo->cur_comp_info[ci]; 209 /* Sampling factors give # of data units of component in each MCU */ 210 compptr->MCU_width = compptr->h_samp_factor; 211 compptr->MCU_height = compptr->v_samp_factor; 212 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; 213 compptr->MCU_sample_width = compptr->MCU_width * 214 compptr->_DCT_scaled_size; 215 /* Figure number of non-dummy data units in last MCU column & row */ 216 tmp = (int)(compptr->width_in_blocks % compptr->MCU_width); 217 if (tmp == 0) tmp = compptr->MCU_width; 218 compptr->last_col_width = tmp; 219 tmp = (int)(compptr->height_in_blocks % compptr->MCU_height); 220 if (tmp == 0) tmp = compptr->MCU_height; 221 compptr->last_row_height = tmp; 222 /* Prepare array describing MCU composition */ 223 mcublks = compptr->MCU_blocks; 224 if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU) 225 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); 226 while (mcublks-- > 0) { 227 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; 228 } 229 } 230 231 } 232 } 233 234 235 /* 236 * Save away a copy of the Q-table referenced by each component present 237 * in the current scan, unless already saved during a prior scan. 238 * 239 * In a multiple-scan JPEG file, the encoder could assign different components 240 * the same Q-table slot number, but change table definitions between scans 241 * so that each component uses a different Q-table. (The IJG encoder is not 242 * currently capable of doing this, but other encoders might.) Since we want 243 * to be able to dequantize all the components at the end of the file, this 244 * means that we have to save away the table actually used for each component. 245 * We do this by copying the table at the start of the first scan containing 246 * the component. 247 * Rec. ITU-T T.81 | ISO/IEC 10918-1 prohibits the encoder from changing the 248 * contents of a Q-table slot between scans of a component using that slot. If 249 * the encoder does so anyway, this decoder will simply use the Q-table values 250 * that were current at the start of the first scan for the component. 251 * 252 * The decompressor output side looks only at the saved quant tables, 253 * not at the current Q-table slots. 254 */ 255 256 LOCAL(void) 257 latch_quant_tables(j_decompress_ptr cinfo) 258 { 259 int ci, qtblno; 260 jpeg_component_info *compptr; 261 JQUANT_TBL *qtbl; 262 263 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 264 compptr = cinfo->cur_comp_info[ci]; 265 /* No work if we already saved Q-table for this component */ 266 if (compptr->quant_table != NULL) 267 continue; 268 /* Make sure specified quantization table is present */ 269 qtblno = compptr->quant_tbl_no; 270 if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || 271 cinfo->quant_tbl_ptrs[qtblno] == NULL) 272 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); 273 /* OK, save away the quantization table */ 274 qtbl = (JQUANT_TBL *) 275 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, 276 sizeof(JQUANT_TBL)); 277 memcpy(qtbl, cinfo->quant_tbl_ptrs[qtblno], sizeof(JQUANT_TBL)); 278 compptr->quant_table = qtbl; 279 } 280 } 281 282 283 /* 284 * Initialize the input modules to read a scan of compressed data. 285 * The first call to this is done by jdmaster.c after initializing 286 * the entire decompressor (during jpeg_start_decompress). 287 * Subsequent calls come from consume_markers, below. 288 */ 289 290 METHODDEF(void) 291 start_input_pass(j_decompress_ptr cinfo) 292 { 293 per_scan_setup(cinfo); 294 if (!cinfo->master->lossless) 295 latch_quant_tables(cinfo); 296 (*cinfo->entropy->start_pass) (cinfo); 297 (*cinfo->coef->start_input_pass) (cinfo); 298 cinfo->inputctl->consume_input = cinfo->coef->consume_data; 299 } 300 301 302 /* 303 * Finish up after inputting a compressed-data scan. 304 * This is called by the coefficient or difference controller after it's read 305 * all the expected data of the scan. 306 */ 307 308 METHODDEF(void) 309 finish_input_pass(j_decompress_ptr cinfo) 310 { 311 cinfo->inputctl->consume_input = consume_markers; 312 } 313 314 315 /* 316 * Read JPEG markers before, between, or after compressed-data scans. 317 * Change state as necessary when a new scan is reached. 318 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 319 * 320 * The consume_input method pointer points either here or to the 321 * coefficient or difference controller's consume_data routine, depending on 322 * whether we are reading a compressed data segment or inter-segment markers. 323 */ 324 325 METHODDEF(int) 326 consume_markers(j_decompress_ptr cinfo) 327 { 328 my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl; 329 int val; 330 331 if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */ 332 return JPEG_REACHED_EOI; 333 334 val = (*cinfo->marker->read_markers) (cinfo); 335 336 switch (val) { 337 case JPEG_REACHED_SOS: /* Found SOS */ 338 if (inputctl->inheaders) { /* 1st SOS */ 339 initial_setup(cinfo); 340 inputctl->inheaders = FALSE; 341 /* Note: start_input_pass must be called by jdmaster.c 342 * before any more input can be consumed. jdapimin.c is 343 * responsible for enforcing this sequencing. 344 */ 345 } else { /* 2nd or later SOS marker */ 346 if (!inputctl->pub.has_multiple_scans) 347 ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */ 348 start_input_pass(cinfo); 349 } 350 break; 351 case JPEG_REACHED_EOI: /* Found EOI */ 352 inputctl->pub.eoi_reached = TRUE; 353 if (inputctl->inheaders) { /* Tables-only datastream, apparently */ 354 if (cinfo->marker->saw_SOF) 355 ERREXIT(cinfo, JERR_SOF_NO_SOS); 356 } else { 357 /* Prevent infinite loop in coef ctlr's decompress_data routine 358 * if user set output_scan_number larger than number of scans. 359 */ 360 if (cinfo->output_scan_number > cinfo->input_scan_number) 361 cinfo->output_scan_number = cinfo->input_scan_number; 362 } 363 break; 364 case JPEG_SUSPENDED: 365 break; 366 } 367 368 return val; 369 } 370 371 372 /* 373 * Reset state to begin a fresh datastream. 374 */ 375 376 METHODDEF(void) 377 reset_input_controller(j_decompress_ptr cinfo) 378 { 379 my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl; 380 381 inputctl->pub.consume_input = consume_markers; 382 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ 383 inputctl->pub.eoi_reached = FALSE; 384 inputctl->inheaders = TRUE; 385 /* Reset other modules */ 386 (*cinfo->err->reset_error_mgr) ((j_common_ptr)cinfo); 387 (*cinfo->marker->reset_marker_reader) (cinfo); 388 /* Reset progression state -- would be cleaner if entropy decoder did this */ 389 cinfo->coef_bits = NULL; 390 } 391 392 393 /* 394 * Initialize the input controller module. 395 * This is called only once, when the decompression object is created. 396 */ 397 398 GLOBAL(void) 399 jinit_input_controller(j_decompress_ptr cinfo) 400 { 401 my_inputctl_ptr inputctl; 402 403 /* Create subobject in permanent pool */ 404 inputctl = (my_inputctl_ptr) 405 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT, 406 sizeof(my_input_controller)); 407 cinfo->inputctl = (struct jpeg_input_controller *)inputctl; 408 /* Initialize method pointers */ 409 inputctl->pub.consume_input = consume_markers; 410 inputctl->pub.reset_input_controller = reset_input_controller; 411 inputctl->pub.start_input_pass = start_input_pass; 412 inputctl->pub.finish_input_pass = finish_input_pass; 413 /* Initialize state: can't use reset_input_controller since we don't 414 * want to try to reset other modules yet. 415 */ 416 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ 417 inputctl->pub.eoi_reached = FALSE; 418 inputctl->inheaders = TRUE; 419 }