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