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