media/libjpeg/jdinput.c

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