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| 1 /* | |
| 2 * jdinput.c | |
| 3 * | |
| 4 * Copyright (C) 1991-1997, Thomas G. Lane. | |
| 5 * This file is part of the Independent JPEG Group's software. | |
| 6 * For conditions of distribution and use, see the accompanying README file. | |
| 7 * | |
| 8 * This file contains input control logic for the JPEG decompressor. | |
| 9 * These routines are concerned with controlling the decompressor's input | |
| 10 * processing (marker reading and coefficient decoding). The actual input | |
| 11 * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c. | |
| 12 */ | |
| 13 | |
| 14 #define JPEG_INTERNALS | |
| 15 #include "jinclude.h" | |
| 16 #include "jpeglib.h" | |
| 17 | |
| 18 | |
| 19 /* Private state */ | |
| 20 | |
| 21 typedef struct { | |
| 22 struct jpeg_input_controller pub; /* public fields */ | |
| 23 | |
| 24 boolean inheaders; /* TRUE until first SOS is reached */ | |
| 25 } my_input_controller; | |
| 26 | |
| 27 typedef my_input_controller * my_inputctl_ptr; | |
| 28 | |
| 29 | |
| 30 /* Forward declarations */ | |
| 31 METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo)); | |
| 32 | |
| 33 | |
| 34 /* | |
| 35 * Routines to calculate various quantities related to the size of the image. | |
| 36 */ | |
| 37 | |
| 38 LOCAL(void) | |
| 39 initial_setup (j_decompress_ptr cinfo) | |
| 40 /* Called once, when first SOS marker is reached */ | |
| 41 { | |
| 42 int ci; | |
| 43 jpeg_component_info *compptr; | |
| 44 | |
| 45 /* Make sure image isn't bigger than I can handle */ | |
| 46 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION || | |
| 47 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION) | |
| 48 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); | |
| 49 | |
| 50 /* For now, precision must match compiled-in value... */ | |
| 51 if (cinfo->data_precision != BITS_IN_JSAMPLE) | |
| 52 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); | |
| 53 | |
| 54 /* Check that number of components won't exceed internal array sizes */ | |
| 55 if (cinfo->num_components > MAX_COMPONENTS) | |
| 56 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, | |
| 57 MAX_COMPONENTS); | |
| 58 | |
| 59 /* Compute maximum sampling factors; check factor validity */ | |
| 60 cinfo->max_h_samp_factor = 1; | |
| 61 cinfo->max_v_samp_factor = 1; | |
| 62 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
| 63 ci++, compptr++) { | |
| 64 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR || | |
| 65 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR) | |
| 66 ERREXIT(cinfo, JERR_BAD_SAMPLING); | |
| 67 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, | |
| 68 compptr->h_samp_factor); | |
| 69 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, | |
| 70 compptr->v_samp_factor); | |
| 71 } | |
| 72 | |
| 73 /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE. | |
| 74 * In the full decompressor, this will be overridden by jdmaster.c; | |
| 75 * but in the transcoder, jdmaster.c is not used, so we must do it here. | |
| 76 */ | |
| 77 cinfo->min_DCT_scaled_size = DCTSIZE; | |
| 78 | |
| 79 /* Compute dimensions of components */ | |
| 80 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
| 81 ci++, compptr++) { | |
| 82 compptr->DCT_scaled_size = DCTSIZE; | |
| 83 /* Size in DCT blocks */ | |
| 84 compptr->width_in_blocks = (JDIMENSION) | |
| 85 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, | |
| 86 (long) (cinfo->max_h_samp_factor * DCTSIZE)); | |
| 87 compptr->height_in_blocks = (JDIMENSION) | |
| 88 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, | |
| 89 (long) (cinfo->max_v_samp_factor * DCTSIZE)); | |
| 90 /* downsampled_width and downsampled_height will also be overridden by | |
| 91 * jdmaster.c if we are doing full decompression. The transcoder library | |
| 92 * doesn't use these values, but the calling application might. | |
| 93 */ | |
| 94 /* Size in samples */ | |
| 95 compptr->downsampled_width = (JDIMENSION) | |
| 96 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, | |
| 97 (long) cinfo->max_h_samp_factor); | |
| 98 compptr->downsampled_height = (JDIMENSION) | |
| 99 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, | |
| 100 (long) cinfo->max_v_samp_factor); | |
| 101 /* Mark component needed, until color conversion says otherwise */ | |
| 102 compptr->component_needed = TRUE; | |
| 103 /* Mark no quantization table yet saved for component */ | |
| 104 compptr->quant_table = NULL; | |
| 105 } | |
| 106 | |
| 107 /* Compute number of fully interleaved MCU rows. */ | |
| 108 cinfo->total_iMCU_rows = (JDIMENSION) | |
| 109 jdiv_round_up((long) cinfo->image_height, | |
| 110 (long) (cinfo->max_v_samp_factor*DCTSIZE)); | |
| 111 | |
| 112 /* Decide whether file contains multiple scans */ | |
| 113 if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode) | |
| 114 cinfo->inputctl->has_multiple_scans = TRUE; | |
| 115 else | |
| 116 cinfo->inputctl->has_multiple_scans = FALSE; | |
| 117 } | |
| 118 | |
| 119 | |
| 120 LOCAL(void) | |
| 121 per_scan_setup (j_decompress_ptr cinfo) | |
| 122 /* Do computations that are needed before processing a JPEG scan */ | |
| 123 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */ | |
| 124 { | |
| 125 int ci, mcublks, tmp; | |
| 126 jpeg_component_info *compptr; | |
| 127 | |
| 128 if (cinfo->comps_in_scan == 1) { | |
| 129 | |
| 130 /* Noninterleaved (single-component) scan */ | |
| 131 compptr = cinfo->cur_comp_info[0]; | |
| 132 | |
| 133 /* Overall image size in MCUs */ | |
| 134 cinfo->MCUs_per_row = compptr->width_in_blocks; | |
| 135 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; | |
| 136 | |
| 137 /* For noninterleaved scan, always one block per MCU */ | |
| 138 compptr->MCU_width = 1; | |
| 139 compptr->MCU_height = 1; | |
| 140 compptr->MCU_blocks = 1; | |
| 141 compptr->MCU_sample_width = compptr->DCT_scaled_size; | |
| 142 compptr->last_col_width = 1; | |
| 143 /* For noninterleaved scans, it is convenient to define last_row_height | |
| 144 * as the number of block rows present in the last iMCU row. | |
| 145 */ | |
| 146 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); | |
| 147 if (tmp == 0) tmp = compptr->v_samp_factor; | |
| 148 compptr->last_row_height = tmp; | |
| 149 | |
| 150 /* Prepare array describing MCU composition */ | |
| 151 cinfo->blocks_in_MCU = 1; | |
| 152 cinfo->MCU_membership[0] = 0; | |
| 153 | |
| 154 } else { | |
| 155 | |
| 156 /* Interleaved (multi-component) scan */ | |
| 157 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) | |
| 158 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, | |
| 159 MAX_COMPS_IN_SCAN); | |
| 160 | |
| 161 /* Overall image size in MCUs */ | |
| 162 cinfo->MCUs_per_row = (JDIMENSION) | |
| 163 jdiv_round_up((long) cinfo->image_width, | |
| 164 (long) (cinfo->max_h_samp_factor*DCTSIZE)); | |
| 165 cinfo->MCU_rows_in_scan = (JDIMENSION) | |
| 166 jdiv_round_up((long) cinfo->image_height, | |
| 167 (long) (cinfo->max_v_samp_factor*DCTSIZE)); | |
| 168 | |
| 169 cinfo->blocks_in_MCU = 0; | |
| 170 | |
| 171 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | |
| 172 compptr = cinfo->cur_comp_info[ci]; | |
| 173 /* Sampling factors give # of blocks of component in each MCU */ | |
| 174 compptr->MCU_width = compptr->h_samp_factor; | |
| 175 compptr->MCU_height = compptr->v_samp_factor; | |
| 176 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; | |
| 177 compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_scaled_size; | |
| 178 /* Figure number of non-dummy blocks in last MCU column & row */ | |
| 179 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width); | |
| 180 if (tmp == 0) tmp = compptr->MCU_width; | |
| 181 compptr->last_col_width = tmp; | |
| 182 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height); | |
| 183 if (tmp == 0) tmp = compptr->MCU_height; | |
| 184 compptr->last_row_height = tmp; | |
| 185 /* Prepare array describing MCU composition */ | |
| 186 mcublks = compptr->MCU_blocks; | |
| 187 if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU) | |
| 188 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); | |
| 189 while (mcublks-- > 0) { | |
| 190 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; | |
| 191 } | |
| 192 } | |
| 193 | |
| 194 } | |
| 195 } | |
| 196 | |
| 197 | |
| 198 /* | |
| 199 * Save away a copy of the Q-table referenced by each component present | |
| 200 * in the current scan, unless already saved during a prior scan. | |
| 201 * | |
| 202 * In a multiple-scan JPEG file, the encoder could assign different components | |
| 203 * the same Q-table slot number, but change table definitions between scans | |
| 204 * so that each component uses a different Q-table. (The IJG encoder is not | |
| 205 * currently capable of doing this, but other encoders might.) Since we want | |
| 206 * to be able to dequantize all the components at the end of the file, this | |
| 207 * means that we have to save away the table actually used for each component. | |
| 208 * We do this by copying the table at the start of the first scan containing | |
| 209 * the component. | |
| 210 * The JPEG spec prohibits the encoder from changing the contents of a Q-table | |
| 211 * slot between scans of a component using that slot. If the encoder does so | |
| 212 * anyway, this decoder will simply use the Q-table values that were current | |
| 213 * at the start of the first scan for the component. | |
| 214 * | |
| 215 * The decompressor output side looks only at the saved quant tables, | |
| 216 * not at the current Q-table slots. | |
| 217 */ | |
| 218 | |
| 219 LOCAL(void) | |
| 220 latch_quant_tables (j_decompress_ptr cinfo) | |
| 221 { | |
| 222 int ci, qtblno; | |
| 223 jpeg_component_info *compptr; | |
| 224 JQUANT_TBL * qtbl; | |
| 225 | |
| 226 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { | |
| 227 compptr = cinfo->cur_comp_info[ci]; | |
| 228 /* No work if we already saved Q-table for this component */ | |
| 229 if (compptr->quant_table != NULL) | |
| 230 continue; | |
| 231 /* Make sure specified quantization table is present */ | |
| 232 qtblno = compptr->quant_tbl_no; | |
| 233 if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || | |
| 234 cinfo->quant_tbl_ptrs[qtblno] == NULL) | |
| 235 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); | |
| 236 /* OK, save away the quantization table */ | |
| 237 qtbl = (JQUANT_TBL *) | |
| 238 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 239 SIZEOF(JQUANT_TBL)); | |
| 240 MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL)); | |
| 241 compptr->quant_table = qtbl; | |
| 242 } | |
| 243 } | |
| 244 | |
| 245 | |
| 246 /* | |
| 247 * Initialize the input modules to read a scan of compressed data. | |
| 248 * The first call to this is done by jdmaster.c after initializing | |
| 249 * the entire decompressor (during jpeg_start_decompress). | |
| 250 * Subsequent calls come from consume_markers, below. | |
| 251 */ | |
| 252 | |
| 253 METHODDEF(void) | |
| 254 start_input_pass (j_decompress_ptr cinfo) | |
| 255 { | |
| 256 per_scan_setup(cinfo); | |
| 257 latch_quant_tables(cinfo); | |
| 258 (*cinfo->entropy->start_pass) (cinfo); | |
| 259 (*cinfo->coef->start_input_pass) (cinfo); | |
| 260 cinfo->inputctl->consume_input = cinfo->coef->consume_data; | |
| 261 } | |
| 262 | |
| 263 | |
| 264 /* | |
| 265 * Finish up after inputting a compressed-data scan. | |
| 266 * This is called by the coefficient controller after it's read all | |
| 267 * the expected data of the scan. | |
| 268 */ | |
| 269 | |
| 270 METHODDEF(void) | |
| 271 finish_input_pass (j_decompress_ptr cinfo) | |
| 272 { | |
| 273 cinfo->inputctl->consume_input = consume_markers; | |
| 274 } | |
| 275 | |
| 276 | |
| 277 /* | |
| 278 * Read JPEG markers before, between, or after compressed-data scans. | |
| 279 * Change state as necessary when a new scan is reached. | |
| 280 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. | |
| 281 * | |
| 282 * The consume_input method pointer points either here or to the | |
| 283 * coefficient controller's consume_data routine, depending on whether | |
| 284 * we are reading a compressed data segment or inter-segment markers. | |
| 285 */ | |
| 286 | |
| 287 METHODDEF(int) | |
| 288 consume_markers (j_decompress_ptr cinfo) | |
| 289 { | |
| 290 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl; | |
| 291 int val; | |
| 292 | |
| 293 if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */ | |
| 294 return JPEG_REACHED_EOI; | |
| 295 | |
| 296 val = (*cinfo->marker->read_markers) (cinfo); | |
| 297 | |
| 298 switch (val) { | |
| 299 case JPEG_REACHED_SOS: /* Found SOS */ | |
| 300 if (inputctl->inheaders) { /* 1st SOS */ | |
| 301 initial_setup(cinfo); | |
| 302 inputctl->inheaders = FALSE; | |
| 303 /* Note: start_input_pass must be called by jdmaster.c | |
| 304 * before any more input can be consumed. jdapimin.c is | |
| 305 * responsible for enforcing this sequencing. | |
| 306 */ | |
| 307 } else { /* 2nd or later SOS marker */ | |
| 308 if (! inputctl->pub.has_multiple_scans) | |
| 309 ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */ | |
| 310 start_input_pass(cinfo); | |
| 311 } | |
| 312 break; | |
| 313 case JPEG_REACHED_EOI: /* Found EOI */ | |
| 314 inputctl->pub.eoi_reached = TRUE; | |
| 315 if (inputctl->inheaders) { /* Tables-only datastream, apparently */ | |
| 316 if (cinfo->marker->saw_SOF) | |
| 317 ERREXIT(cinfo, JERR_SOF_NO_SOS); | |
| 318 } else { | |
| 319 /* Prevent infinite loop in coef ctlr's decompress_data routine | |
| 320 * if user set output_scan_number larger than number of scans. | |
| 321 */ | |
| 322 if (cinfo->output_scan_number > cinfo->input_scan_number) | |
| 323 cinfo->output_scan_number = cinfo->input_scan_number; | |
| 324 } | |
| 325 break; | |
| 326 case JPEG_SUSPENDED: | |
| 327 break; | |
| 328 } | |
| 329 | |
| 330 return val; | |
| 331 } | |
| 332 | |
| 333 | |
| 334 /* | |
| 335 * Reset state to begin a fresh datastream. | |
| 336 */ | |
| 337 | |
| 338 METHODDEF(void) | |
| 339 reset_input_controller (j_decompress_ptr cinfo) | |
| 340 { | |
| 341 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl; | |
| 342 | |
| 343 inputctl->pub.consume_input = consume_markers; | |
| 344 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ | |
| 345 inputctl->pub.eoi_reached = FALSE; | |
| 346 inputctl->inheaders = TRUE; | |
| 347 /* Reset other modules */ | |
| 348 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); | |
| 349 (*cinfo->marker->reset_marker_reader) (cinfo); | |
| 350 /* Reset progression state -- would be cleaner if entropy decoder did this */ | |
| 351 cinfo->coef_bits = NULL; | |
| 352 } | |
| 353 | |
| 354 | |
| 355 /* | |
| 356 * Initialize the input controller module. | |
| 357 * This is called only once, when the decompression object is created. | |
| 358 */ | |
| 359 | |
| 360 GLOBAL(void) | |
| 361 jinit_input_controller (j_decompress_ptr cinfo) | |
| 362 { | |
| 363 my_inputctl_ptr inputctl; | |
| 364 | |
| 365 /* Create subobject in permanent pool */ | |
| 366 inputctl = (my_inputctl_ptr) | |
| 367 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, | |
| 368 SIZEOF(my_input_controller)); | |
| 369 cinfo->inputctl = (struct jpeg_input_controller *) inputctl; | |
| 370 /* Initialize method pointers */ | |
| 371 inputctl->pub.consume_input = consume_markers; | |
| 372 inputctl->pub.reset_input_controller = reset_input_controller; | |
| 373 inputctl->pub.start_input_pass = start_input_pass; | |
| 374 inputctl->pub.finish_input_pass = finish_input_pass; | |
| 375 /* Initialize state: can't use reset_input_controller since we don't | |
| 376 * want to try to reset other modules yet. | |
| 377 */ | |
| 378 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ | |
| 379 inputctl->pub.eoi_reached = FALSE; | |
| 380 inputctl->inheaders = TRUE; | |
| 381 } | |
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Chromium Code Reviews
Issue 1705523002:
Remove libjpeg and libjpeg_turbo. (Closed)
Base URL: https://github.com/domokit/mojo.git@master