/media/libjpeg/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
 24typedef struct {
 25  struct jpeg_input_controller pub; /* public fields */
 26
 27  boolean inheaders;		/* TRUE until first SOS is reached */
 28} my_input_controller;
 29
 30typedef my_input_controller * my_inputctl_ptr;
 31
 32
 33/* Forward declarations */
 34METHODDEF(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
 49GLOBAL(void)
 50jpeg_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
114LOCAL(void)
115initial_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
210LOCAL(void)
211per_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
309LOCAL(void)
310latch_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
343METHODDEF(void)
344start_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
360METHODDEF(void)
361finish_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
377METHODDEF(int)
378consume_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
428METHODDEF(void)
429reset_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
450GLOBAL(void)
451jinit_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}