jpeg/jdinput.c

   1 /*
   2  * jdinput.c
   3  *
   4  * Copyright (C) 1991-1997, Thomas G. Lane.
   5  * Modified 2002-2009 by Guido Vollbeding.
   6  * Copyright (C) 2010, D. R. Commander.
   7  * This file is part of the Independent JPEG Group's software.
   8  * For conditions of distribution and use, see the accompanying README file.
   9  *
  10  * This file contains input control logic for the JPEG decompressor.
  11  * These routines are concerned with controlling the decompressor's input
  12  * processing (marker reading and coefficient decoding).  The actual input
  13  * reading is done in jdmarker.c, jdhuff.c, and jdphuff.c.
  14  */
  15
  16 #define JPEG_INTERNALS
  17 #include "jinclude.h"
  18 #include "jpeglib.h"
  19 #include "jpegcomp.h"
  20
  21
  22 /* Private state */
  23
  24 typedef struct {
  25   struct jpeg_input_controller pub; /* public fields */
  26
  27   boolean inheaders;            /* TRUE until first SOS is reached */
  28 } my_input_controller;
  29
  30 typedef my_input_controller * my_inputctl_ptr;
  31
  32
  33 /* Forward declarations */
  34 METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
  35
  36
  37 /*
  38  * Routines to calculate various quantities related to the size of the image.
  39  */
  40
  41
  42 #if JPEG_LIB_VERSION >= 80
  43 /*
  44  * Compute output image dimensions and related values.
  45  * NOTE: this is exported for possible use by application.
  46  * Hence it mustn't do anything that can't be done twice.
  47  */
  48
  49 GLOBAL(void)
  50 jpeg_core_output_dimensions (j_decompress_ptr cinfo)
  51 /* Do computations that are needed before master selection phase.
  52  * This function is used for transcoding and full decompression.
  53  */
  54 {
  55 #ifdef IDCT_SCALING_SUPPORTED
  56   int ci;
  57   jpeg_component_info *compptr;
  58
  59   /* Compute actual output image dimensions and DCT scaling choices. */
  60   if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) {
  61     /* Provide 1/block_size scaling */
  62     cinfo->output_width = (JDIMENSION)
  63       jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size);
  64     cinfo->output_height = (JDIMENSION)
  65       jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size);
  66     cinfo->min_DCT_h_scaled_size = 1;
  67     cinfo->min_DCT_v_scaled_size = 1;
  68   } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) {
  69     /* Provide 2/block_size scaling */
  70     cinfo->output_width = (JDIMENSION)
  71       jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size);
  72     cinfo->output_height = (JDIMENSION)
  73       jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size);
  74     cinfo->min_DCT_h_scaled_size = 2;
  75     cinfo->min_DCT_v_scaled_size = 2;
  76   } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) {
  77     /* Provide 4/block_size scaling */
  78     cinfo->output_width = (JDIMENSION)
  79       jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size);
  80     cinfo->output_height = (JDIMENSION)
  81       jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size);
  82     cinfo->min_DCT_h_scaled_size = 4;
  83     cinfo->min_DCT_v_scaled_size = 4;
  84   } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) {
  85     /* Provide 8/block_size scaling */
  86     cinfo->output_width = (JDIMENSION)
  87       jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size);
  88     cinfo->output_height = (JDIMENSION)
  89       jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size);
  90     cinfo->min_DCT_h_scaled_size = 8;
  91     cinfo->min_DCT_v_scaled_size = 8;
  92   }
  93   /* Recompute dimensions of components */
  94   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
  95        ci++, compptr++) {
  96     compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size;
  97     compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size;
  98   }
  99
 100 #else /* !IDCT_SCALING_SUPPORTED */
 101
 102   /* Hardwire it to "no scaling" */
 103   cinfo->output_width = cinfo->image_width;
 104   cinfo->output_height = cinfo->image_height;
 105   /* jdinput.c has already initialized DCT_scaled_size,
 106    * and has computed unscaled downsampled_width and downsampled_height.
 107    */
 108
 109 #endif /* IDCT_SCALING_SUPPORTED */
 110 }
 111 #endif
 112
 113
 114 LOCAL(void)
 115 initial_setup (j_decompress_ptr cinfo)
 116 /* Called once, when first SOS marker is reached */
 117 {
 118   int ci;
 119   jpeg_component_info *compptr;
 120
 121   /* Make sure image isn't bigger than I can handle */
 122   if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
 123       (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
 124     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
 125
 126   /* For now, precision must match compiled-in value... */
 127   if (cinfo->data_precision != BITS_IN_JSAMPLE)
 128     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
 129
 130   /* Check that number of components won't exceed internal array sizes */
 131   if (cinfo->num_components > MAX_COMPONENTS)
 132     ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
 133              MAX_COMPONENTS);
 134
 135   /* Compute maximum sampling factors; check factor validity */
 136   cinfo->max_h_samp_factor = 1;
 137   cinfo->max_v_samp_factor = 1;
 138   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 139        ci++, compptr++) {
 140     if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
 141         compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
 142       ERREXIT(cinfo, JERR_BAD_SAMPLING);
 143     cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
 144                                    compptr->h_samp_factor);
 145     cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
 146                                    compptr->v_samp_factor);
 147   }
 148
 149 #if JPEG_LIB_VERSION >=80
 150     cinfo->block_size = DCTSIZE;
 151     cinfo->natural_order = jpeg_natural_order;
 152     cinfo->lim_Se = DCTSIZE2-1;
 153 #endif
 154
 155   /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
 156    * In the full decompressor, this will be overridden by jdmaster.c;
 157    * but in the transcoder, jdmaster.c is not used, so we must do it here.
 158    */
 159 #if JPEG_LIB_VERSION >= 70
 160   cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
 161 #else
 162   cinfo->min_DCT_scaled_size = DCTSIZE;
 163 #endif
 164
 165   /* Compute dimensions of components */
 166   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 167        ci++, compptr++) {
 168 #if JPEG_LIB_VERSION >= 70
 169     compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
 170 #else
 171     compptr->DCT_scaled_size = DCTSIZE;
 172 #endif
 173     /* Size in DCT blocks */
 174     compptr->width_in_blocks = (JDIMENSION)
 175       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 176                     (long) (cinfo->max_h_samp_factor * DCTSIZE));
 177     compptr->height_in_blocks = (JDIMENSION)
 178       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 179                     (long) (cinfo->max_v_samp_factor * DCTSIZE));
 180     /* downsampled_width and downsampled_height will also be overridden by
 181      * jdmaster.c if we are doing full decompression.  The transcoder library
 182      * doesn't use these values, but the calling application might.
 183      */
 184     /* Size in samples */
 185     compptr->downsampled_width = (JDIMENSION)
 186       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
 187                     (long) cinfo->max_h_samp_factor);
 188     compptr->downsampled_height = (JDIMENSION)
 189       jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
 190                     (long) cinfo->max_v_samp_factor);
 191     /* Mark component needed, until color conversion says otherwise */
 192     compptr->component_needed = TRUE;
 193     /* Mark no quantization table yet saved for component */
 194     compptr->quant_table = NULL;
 195   }
 196
 197   /* Compute number of fully interleaved MCU rows. */
 198   cinfo->total_iMCU_rows = (JDIMENSION)
 199     jdiv_round_up((long) cinfo->image_height,
 200                   (long) (cinfo->max_v_samp_factor*DCTSIZE));
 201
 202   /* Decide whether file contains multiple scans */
 203   if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
 204     cinfo->inputctl->has_multiple_scans = TRUE;
 205   else
 206     cinfo->inputctl->has_multiple_scans = FALSE;
 207 }
 208
 209
 210 LOCAL(void)
 211 per_scan_setup (j_decompress_ptr cinfo)
 212 /* Do computations that are needed before processing a JPEG scan */
 213 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
 214 {
 215   int ci, mcublks, tmp;
 216   jpeg_component_info *compptr;
 217
 218   if (cinfo->comps_in_scan == 1) {
 219
 220     /* Noninterleaved (single-component) scan */
 221     compptr = cinfo->cur_comp_info[0];
 222
 223     /* Overall image size in MCUs */
 224     cinfo->MCUs_per_row = compptr->width_in_blocks;
 225     cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
 226
 227     /* For noninterleaved scan, always one block per MCU */
 228     compptr->MCU_width = 1;
 229     compptr->MCU_height = 1;
 230     compptr->MCU_blocks = 1;
 231     compptr->MCU_sample_width = compptr->_DCT_scaled_size;
 232     compptr->last_col_width = 1;
 233     /* For noninterleaved scans, it is convenient to define last_row_height
 234      * as the number of block rows present in the last iMCU row.
 235      */
 236     tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
 237     if (tmp == 0) tmp = compptr->v_samp_factor;
 238     compptr->last_row_height = tmp;
 239
 240     /* Prepare array describing MCU composition */
 241     cinfo->blocks_in_MCU = 1;
 242     cinfo->MCU_membership[0] = 0;
 243
 244   } else {
 245
 246     /* Interleaved (multi-component) scan */
 247     if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
 248       ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
 249                MAX_COMPS_IN_SCAN);
 250
 251     /* Overall image size in MCUs */
 252     cinfo->MCUs_per_row = (JDIMENSION)
 253       jdiv_round_up((long) cinfo->image_width,
 254                     (long) (cinfo->max_h_samp_factor*DCTSIZE));
 255     cinfo->MCU_rows_in_scan = (JDIMENSION)
 256       jdiv_round_up((long) cinfo->image_height,
 257                     (long) (cinfo->max_v_samp_factor*DCTSIZE));
 258
 259     cinfo->blocks_in_MCU = 0;
 260
 261     for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 262       compptr = cinfo->cur_comp_info[ci];
 263       /* Sampling factors give # of blocks of component in each MCU */
 264       compptr->MCU_width = compptr->h_samp_factor;
 265       compptr->MCU_height = compptr->v_samp_factor;
 266       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
 267       compptr->MCU_sample_width = compptr->MCU_width * compptr->_DCT_scaled_size;
 268       /* Figure number of non-dummy blocks in last MCU column & row */
 269       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
 270       if (tmp == 0) tmp = compptr->MCU_width;
 271       compptr->last_col_width = tmp;
 272       tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
 273       if (tmp == 0) tmp = compptr->MCU_height;
 274       compptr->last_row_height = tmp;
 275       /* Prepare array describing MCU composition */
 276       mcublks = compptr->MCU_blocks;
 277       if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
 278         ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
 279       while (mcublks-- > 0) {
 280         cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
 281       }
 282     }
 283
 284   }
 285 }
 286
 287
 288 /*
 289  * Save away a copy of the Q-table referenced by each component present
 290  * in the current scan, unless already saved during a prior scan.
 291  *
 292  * In a multiple-scan JPEG file, the encoder could assign different components
 293  * the same Q-table slot number, but change table definitions between scans
 294  * so that each component uses a different Q-table.  (The IJG encoder is not
 295  * currently capable of doing this, but other encoders might.)  Since we want
 296  * to be able to dequantize all the components at the end of the file, this
 297  * means that we have to save away the table actually used for each component.
 298  * We do this by copying the table at the start of the first scan containing
 299  * the component.
 300  * The JPEG spec prohibits the encoder from changing the contents of a Q-table
 301  * slot between scans of a component using that slot.  If the encoder does so
 302  * anyway, this decoder will simply use the Q-table values that were current
 303  * at the start of the first scan for the component.
 304  *
 305  * The decompressor output side looks only at the saved quant tables,
 306  * not at the current Q-table slots.
 307  */
 308
 309 LOCAL(void)
 310 latch_quant_tables (j_decompress_ptr cinfo)
 311 {
 312   int ci, qtblno;
 313   jpeg_component_info *compptr;
 314   JQUANT_TBL * qtbl;
 315
 316   for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
 317     compptr = cinfo->cur_comp_info[ci];
 318     /* No work if we already saved Q-table for this component */
 319     if (compptr->quant_table != NULL)
 320       continue;
 321     /* Make sure specified quantization table is present */
 322     qtblno = compptr->quant_tbl_no;
 323     if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
 324         cinfo->quant_tbl_ptrs[qtblno] == NULL)
 325       ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
 326     /* OK, save away the quantization table */
 327     qtbl = (JQUANT_TBL *)
 328       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 329                                   SIZEOF(JQUANT_TBL));
 330     MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
 331     compptr->quant_table = qtbl;
 332   }
 333 }
 334
 335
 336 /*
 337  * Initialize the input modules to read a scan of compressed data.
 338  * The first call to this is done by jdmaster.c after initializing
 339  * the entire decompressor (during jpeg_start_decompress).
 340  * Subsequent calls come from consume_markers, below.
 341  */
 342
 343 METHODDEF(void)
 344 start_input_pass (j_decompress_ptr cinfo)
 345 {
 346   per_scan_setup(cinfo);
 347   latch_quant_tables(cinfo);
 348   (*cinfo->entropy->start_pass) (cinfo);
 349   (*cinfo->coef->start_input_pass) (cinfo);
 350   cinfo->inputctl->consume_input = cinfo->coef->consume_data;
 351 }
 352
 353
 354 /*
 355  * Finish up after inputting a compressed-data scan.
 356  * This is called by the coefficient controller after it's read all
 357  * the expected data of the scan.
 358  */
 359
 360 METHODDEF(void)
 361 finish_input_pass (j_decompress_ptr cinfo)
 362 {
 363   cinfo->inputctl->consume_input = consume_markers;
 364 }
 365
 366
 367 /*
 368  * Read JPEG markers before, between, or after compressed-data scans.
 369  * Change state as necessary when a new scan is reached.
 370  * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
 371  *
 372  * The consume_input method pointer points either here or to the
 373  * coefficient controller's consume_data routine, depending on whether
 374  * we are reading a compressed data segment or inter-segment markers.
 375  */
 376
 377 METHODDEF(int)
 378 consume_markers (j_decompress_ptr cinfo)
 379 {
 380   my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
 381   int val;
 382
 383   if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
 384     return JPEG_REACHED_EOI;
 385
 386   val = (*cinfo->marker->read_markers) (cinfo);
 387
 388   switch (val) {
 389   case JPEG_REACHED_SOS:        /* Found SOS */
 390     if (inputctl->inheaders) {  /* 1st SOS */
 391       initial_setup(cinfo);
 392       inputctl->inheaders = FALSE;
 393       /* Note: start_input_pass must be called by jdmaster.c
 394        * before any more input can be consumed.  jdapimin.c is
 395        * responsible for enforcing this sequencing.
 396        */
 397     } else {                    /* 2nd or later SOS marker */
 398       if (! inputctl->pub.has_multiple_scans)
 399         ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
 400       start_input_pass(cinfo);
 401     }
 402     break;
 403   case JPEG_REACHED_EOI:        /* Found EOI */
 404     inputctl->pub.eoi_reached = TRUE;
 405     if (inputctl->inheaders) {  /* Tables-only datastream, apparently */
 406       if (cinfo->marker->saw_SOF)
 407         ERREXIT(cinfo, JERR_SOF_NO_SOS);
 408     } else {
 409       /* Prevent infinite loop in coef ctlr's decompress_data routine
 410        * if user set output_scan_number larger than number of scans.
 411        */
 412       if (cinfo->output_scan_number > cinfo->input_scan_number)
 413         cinfo->output_scan_number = cinfo->input_scan_number;
 414     }
 415     break;
 416   case JPEG_SUSPENDED:
 417     break;
 418   }
 419
 420   return val;
 421 }
 422
 423
 424 /*
 425  * Reset state to begin a fresh datastream.
 426  */
 427
 428 METHODDEF(void)
 429 reset_input_controller (j_decompress_ptr cinfo)
 430 {
 431   my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
 432
 433   inputctl->pub.consume_input = consume_markers;
 434   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
 435   inputctl->pub.eoi_reached = FALSE;
 436   inputctl->inheaders = TRUE;
 437   /* Reset other modules */
 438   (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
 439   (*cinfo->marker->reset_marker_reader) (cinfo);
 440   /* Reset progression state -- would be cleaner if entropy decoder did this */
 441   cinfo->coef_bits = NULL;
 442 }
 443
 444
 445 /*
 446  * Initialize the input controller module.
 447  * This is called only once, when the decompression object is created.
 448  */
 449
 450 GLOBAL(void)
 451 jinit_input_controller (j_decompress_ptr cinfo)
 452 {
 453   my_inputctl_ptr inputctl;
 454
 455   /* Create subobject in permanent pool */
 456   inputctl = (my_inputctl_ptr)
 457     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
 458                                 SIZEOF(my_input_controller));
 459   cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
 460   /* Initialize method pointers */
 461   inputctl->pub.consume_input = consume_markers;
 462   inputctl->pub.reset_input_controller = reset_input_controller;
 463   inputctl->pub.start_input_pass = start_input_pass;
 464   inputctl->pub.finish_input_pass = finish_input_pass;
 465   /* Initialize state: can't use reset_input_controller since we don't
 466    * want to try to reset other modules yet.
 467    */
 468   inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
 469   inputctl->pub.eoi_reached = FALSE;
 470   inputctl->inheaders = TRUE;
 471 }