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