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/src/FreeImage/Source/LibJPEG/jdinput.c

https://bitbucket.org/cabalistic/ogredeps/
C | 661 lines | 442 code | 66 blank | 153 comment | 81 complexity | 8f43a5fc211cc167969e93a26540c2df MD5 | raw file
  1/*
  2 * jdinput.c
  3 *
  4 * Copyright (C) 1991-1997, Thomas G. Lane.
  5 * Modified 2002-2009 by Guido Vollbeding.
  6 * This file is part of the Independent JPEG Group's software.
  7 * For conditions of distribution and use, see the accompanying README file.
  8 *
  9 * This file contains input control logic for the JPEG decompressor.
 10 * These routines are concerned with controlling the decompressor's input
 11 * processing (marker reading and coefficient decoding).  The actual input
 12 * reading is done in jdmarker.c, jdhuff.c, and jdarith.c.
 13 */
 14
 15#define JPEG_INTERNALS
 16#include "jinclude.h"
 17#include "jpeglib.h"
 18
 19
 20/* Private state */
 21
 22typedef struct {
 23  struct jpeg_input_controller pub; /* public fields */
 24
 25  int inheaders;		/* Nonzero until first SOS is reached */
 26} my_input_controller;
 27
 28typedef my_input_controller * my_inputctl_ptr;
 29
 30
 31/* Forward declarations */
 32METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
 33
 34
 35/*
 36 * Routines to calculate various quantities related to the size of the image.
 37 */
 38
 39
 40/*
 41 * Compute output image dimensions and related values.
 42 * NOTE: this is exported for possible use by application.
 43 * Hence it mustn't do anything that can't be done twice.
 44 */
 45
 46GLOBAL(void)
 47jpeg_core_output_dimensions (j_decompress_ptr cinfo)
 48/* Do computations that are needed before master selection phase.
 49 * This function is used for transcoding and full decompression.
 50 */
 51{
 52#ifdef IDCT_SCALING_SUPPORTED
 53  int ci;
 54  jpeg_component_info *compptr;
 55
 56  /* Compute actual output image dimensions and DCT scaling choices. */
 57  if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) {
 58    /* Provide 1/block_size scaling */
 59    cinfo->output_width = (JDIMENSION)
 60      jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size);
 61    cinfo->output_height = (JDIMENSION)
 62      jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size);
 63    cinfo->min_DCT_h_scaled_size = 1;
 64    cinfo->min_DCT_v_scaled_size = 1;
 65  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) {
 66    /* Provide 2/block_size scaling */
 67    cinfo->output_width = (JDIMENSION)
 68      jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size);
 69    cinfo->output_height = (JDIMENSION)
 70      jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size);
 71    cinfo->min_DCT_h_scaled_size = 2;
 72    cinfo->min_DCT_v_scaled_size = 2;
 73  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 3) {
 74    /* Provide 3/block_size scaling */
 75    cinfo->output_width = (JDIMENSION)
 76      jdiv_round_up((long) cinfo->image_width * 3L, (long) cinfo->block_size);
 77    cinfo->output_height = (JDIMENSION)
 78      jdiv_round_up((long) cinfo->image_height * 3L, (long) cinfo->block_size);
 79    cinfo->min_DCT_h_scaled_size = 3;
 80    cinfo->min_DCT_v_scaled_size = 3;
 81  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) {
 82    /* Provide 4/block_size scaling */
 83    cinfo->output_width = (JDIMENSION)
 84      jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size);
 85    cinfo->output_height = (JDIMENSION)
 86      jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size);
 87    cinfo->min_DCT_h_scaled_size = 4;
 88    cinfo->min_DCT_v_scaled_size = 4;
 89  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 5) {
 90    /* Provide 5/block_size scaling */
 91    cinfo->output_width = (JDIMENSION)
 92      jdiv_round_up((long) cinfo->image_width * 5L, (long) cinfo->block_size);
 93    cinfo->output_height = (JDIMENSION)
 94      jdiv_round_up((long) cinfo->image_height * 5L, (long) cinfo->block_size);
 95    cinfo->min_DCT_h_scaled_size = 5;
 96    cinfo->min_DCT_v_scaled_size = 5;
 97  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 6) {
 98    /* Provide 6/block_size scaling */
 99    cinfo->output_width = (JDIMENSION)
100      jdiv_round_up((long) cinfo->image_width * 6L, (long) cinfo->block_size);
101    cinfo->output_height = (JDIMENSION)
102      jdiv_round_up((long) cinfo->image_height * 6L, (long) cinfo->block_size);
103    cinfo->min_DCT_h_scaled_size = 6;
104    cinfo->min_DCT_v_scaled_size = 6;
105  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 7) {
106    /* Provide 7/block_size scaling */
107    cinfo->output_width = (JDIMENSION)
108      jdiv_round_up((long) cinfo->image_width * 7L, (long) cinfo->block_size);
109    cinfo->output_height = (JDIMENSION)
110      jdiv_round_up((long) cinfo->image_height * 7L, (long) cinfo->block_size);
111    cinfo->min_DCT_h_scaled_size = 7;
112    cinfo->min_DCT_v_scaled_size = 7;
113  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) {
114    /* Provide 8/block_size scaling */
115    cinfo->output_width = (JDIMENSION)
116      jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size);
117    cinfo->output_height = (JDIMENSION)
118      jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size);
119    cinfo->min_DCT_h_scaled_size = 8;
120    cinfo->min_DCT_v_scaled_size = 8;
121  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 9) {
122    /* Provide 9/block_size scaling */
123    cinfo->output_width = (JDIMENSION)
124      jdiv_round_up((long) cinfo->image_width * 9L, (long) cinfo->block_size);
125    cinfo->output_height = (JDIMENSION)
126      jdiv_round_up((long) cinfo->image_height * 9L, (long) cinfo->block_size);
127    cinfo->min_DCT_h_scaled_size = 9;
128    cinfo->min_DCT_v_scaled_size = 9;
129  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 10) {
130    /* Provide 10/block_size scaling */
131    cinfo->output_width = (JDIMENSION)
132      jdiv_round_up((long) cinfo->image_width * 10L, (long) cinfo->block_size);
133    cinfo->output_height = (JDIMENSION)
134      jdiv_round_up((long) cinfo->image_height * 10L, (long) cinfo->block_size);
135    cinfo->min_DCT_h_scaled_size = 10;
136    cinfo->min_DCT_v_scaled_size = 10;
137  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 11) {
138    /* Provide 11/block_size scaling */
139    cinfo->output_width = (JDIMENSION)
140      jdiv_round_up((long) cinfo->image_width * 11L, (long) cinfo->block_size);
141    cinfo->output_height = (JDIMENSION)
142      jdiv_round_up((long) cinfo->image_height * 11L, (long) cinfo->block_size);
143    cinfo->min_DCT_h_scaled_size = 11;
144    cinfo->min_DCT_v_scaled_size = 11;
145  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 12) {
146    /* Provide 12/block_size scaling */
147    cinfo->output_width = (JDIMENSION)
148      jdiv_round_up((long) cinfo->image_width * 12L, (long) cinfo->block_size);
149    cinfo->output_height = (JDIMENSION)
150      jdiv_round_up((long) cinfo->image_height * 12L, (long) cinfo->block_size);
151    cinfo->min_DCT_h_scaled_size = 12;
152    cinfo->min_DCT_v_scaled_size = 12;
153  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 13) {
154    /* Provide 13/block_size scaling */
155    cinfo->output_width = (JDIMENSION)
156      jdiv_round_up((long) cinfo->image_width * 13L, (long) cinfo->block_size);
157    cinfo->output_height = (JDIMENSION)
158      jdiv_round_up((long) cinfo->image_height * 13L, (long) cinfo->block_size);
159    cinfo->min_DCT_h_scaled_size = 13;
160    cinfo->min_DCT_v_scaled_size = 13;
161  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 14) {
162    /* Provide 14/block_size scaling */
163    cinfo->output_width = (JDIMENSION)
164      jdiv_round_up((long) cinfo->image_width * 14L, (long) cinfo->block_size);
165    cinfo->output_height = (JDIMENSION)
166      jdiv_round_up((long) cinfo->image_height * 14L, (long) cinfo->block_size);
167    cinfo->min_DCT_h_scaled_size = 14;
168    cinfo->min_DCT_v_scaled_size = 14;
169  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 15) {
170    /* Provide 15/block_size scaling */
171    cinfo->output_width = (JDIMENSION)
172      jdiv_round_up((long) cinfo->image_width * 15L, (long) cinfo->block_size);
173    cinfo->output_height = (JDIMENSION)
174      jdiv_round_up((long) cinfo->image_height * 15L, (long) cinfo->block_size);
175    cinfo->min_DCT_h_scaled_size = 15;
176    cinfo->min_DCT_v_scaled_size = 15;
177  } else {
178    /* Provide 16/block_size scaling */
179    cinfo->output_width = (JDIMENSION)
180      jdiv_round_up((long) cinfo->image_width * 16L, (long) cinfo->block_size);
181    cinfo->output_height = (JDIMENSION)
182      jdiv_round_up((long) cinfo->image_height * 16L, (long) cinfo->block_size);
183    cinfo->min_DCT_h_scaled_size = 16;
184    cinfo->min_DCT_v_scaled_size = 16;
185  }
186
187  /* Recompute dimensions of components */
188  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
189       ci++, compptr++) {
190    compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size;
191    compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size;
192  }
193
194#else /* !IDCT_SCALING_SUPPORTED */
195
196  /* Hardwire it to "no scaling" */
197  cinfo->output_width = cinfo->image_width;
198  cinfo->output_height = cinfo->image_height;
199  /* jdinput.c has already initialized DCT_scaled_size,
200   * and has computed unscaled downsampled_width and downsampled_height.
201   */
202
203#endif /* IDCT_SCALING_SUPPORTED */
204}
205
206
207LOCAL(void)
208initial_setup (j_decompress_ptr cinfo)
209/* Called once, when first SOS marker is reached */
210{
211  int ci;
212  jpeg_component_info *compptr;
213
214  /* Make sure image isn't bigger than I can handle */
215  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
216      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
217    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
218
219  /* For now, precision must match compiled-in value... */
220  if (cinfo->data_precision != BITS_IN_JSAMPLE)
221    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
222
223  /* Check that number of components won't exceed internal array sizes */
224  if (cinfo->num_components > MAX_COMPONENTS)
225    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
226	     MAX_COMPONENTS);
227
228  /* Compute maximum sampling factors; check factor validity */
229  cinfo->max_h_samp_factor = 1;
230  cinfo->max_v_samp_factor = 1;
231  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
232       ci++, compptr++) {
233    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
234	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
235      ERREXIT(cinfo, JERR_BAD_SAMPLING);
236    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
237				   compptr->h_samp_factor);
238    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
239				   compptr->v_samp_factor);
240  }
241
242  /* Derive block_size, natural_order, and lim_Se */
243  if (cinfo->is_baseline || (cinfo->progressive_mode &&
244      cinfo->comps_in_scan)) { /* no pseudo SOS marker */
245    cinfo->block_size = DCTSIZE;
246    cinfo->natural_order = jpeg_natural_order;
247    cinfo->lim_Se = DCTSIZE2-1;
248  } else
249    switch (cinfo->Se) {
250    case (1*1-1):
251      cinfo->block_size = 1;
252      cinfo->natural_order = jpeg_natural_order; /* not needed */
253      cinfo->lim_Se = cinfo->Se;
254      break;
255    case (2*2-1):
256      cinfo->block_size = 2;
257      cinfo->natural_order = jpeg_natural_order2;
258      cinfo->lim_Se = cinfo->Se;
259      break;
260    case (3*3-1):
261      cinfo->block_size = 3;
262      cinfo->natural_order = jpeg_natural_order3;
263      cinfo->lim_Se = cinfo->Se;
264      break;
265    case (4*4-1):
266      cinfo->block_size = 4;
267      cinfo->natural_order = jpeg_natural_order4;
268      cinfo->lim_Se = cinfo->Se;
269      break;
270    case (5*5-1):
271      cinfo->block_size = 5;
272      cinfo->natural_order = jpeg_natural_order5;
273      cinfo->lim_Se = cinfo->Se;
274      break;
275    case (6*6-1):
276      cinfo->block_size = 6;
277      cinfo->natural_order = jpeg_natural_order6;
278      cinfo->lim_Se = cinfo->Se;
279      break;
280    case (7*7-1):
281      cinfo->block_size = 7;
282      cinfo->natural_order = jpeg_natural_order7;
283      cinfo->lim_Se = cinfo->Se;
284      break;
285    case (8*8-1):
286      cinfo->block_size = 8;
287      cinfo->natural_order = jpeg_natural_order;
288      cinfo->lim_Se = DCTSIZE2-1;
289      break;
290    case (9*9-1):
291      cinfo->block_size = 9;
292      cinfo->natural_order = jpeg_natural_order;
293      cinfo->lim_Se = DCTSIZE2-1;
294      break;
295    case (10*10-1):
296      cinfo->block_size = 10;
297      cinfo->natural_order = jpeg_natural_order;
298      cinfo->lim_Se = DCTSIZE2-1;
299      break;
300    case (11*11-1):
301      cinfo->block_size = 11;
302      cinfo->natural_order = jpeg_natural_order;
303      cinfo->lim_Se = DCTSIZE2-1;
304      break;
305    case (12*12-1):
306      cinfo->block_size = 12;
307      cinfo->natural_order = jpeg_natural_order;
308      cinfo->lim_Se = DCTSIZE2-1;
309      break;
310    case (13*13-1):
311      cinfo->block_size = 13;
312      cinfo->natural_order = jpeg_natural_order;
313      cinfo->lim_Se = DCTSIZE2-1;
314      break;
315    case (14*14-1):
316      cinfo->block_size = 14;
317      cinfo->natural_order = jpeg_natural_order;
318      cinfo->lim_Se = DCTSIZE2-1;
319      break;
320    case (15*15-1):
321      cinfo->block_size = 15;
322      cinfo->natural_order = jpeg_natural_order;
323      cinfo->lim_Se = DCTSIZE2-1;
324      break;
325    case (16*16-1):
326      cinfo->block_size = 16;
327      cinfo->natural_order = jpeg_natural_order;
328      cinfo->lim_Se = DCTSIZE2-1;
329      break;
330    default:
331      ERREXIT4(cinfo, JERR_BAD_PROGRESSION,
332	       cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);
333      break;
334    }
335
336  /* We initialize DCT_scaled_size and min_DCT_scaled_size to block_size.
337   * In the full decompressor,
338   * this will be overridden by jpeg_calc_output_dimensions in jdmaster.c;
339   * but in the transcoder,
340   * jpeg_calc_output_dimensions is not used, so we must do it here.
341   */
342  cinfo->min_DCT_h_scaled_size = cinfo->block_size;
343  cinfo->min_DCT_v_scaled_size = cinfo->block_size;
344
345  /* Compute dimensions of components */
346  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
347       ci++, compptr++) {
348    compptr->DCT_h_scaled_size = cinfo->block_size;
349    compptr->DCT_v_scaled_size = cinfo->block_size;
350    /* Size in DCT blocks */
351    compptr->width_in_blocks = (JDIMENSION)
352      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
353		    (long) (cinfo->max_h_samp_factor * cinfo->block_size));
354    compptr->height_in_blocks = (JDIMENSION)
355      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
356		    (long) (cinfo->max_v_samp_factor * cinfo->block_size));
357    /* downsampled_width and downsampled_height will also be overridden by
358     * jdmaster.c if we are doing full decompression.  The transcoder library
359     * doesn't use these values, but the calling application might.
360     */
361    /* Size in samples */
362    compptr->downsampled_width = (JDIMENSION)
363      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
364		    (long) cinfo->max_h_samp_factor);
365    compptr->downsampled_height = (JDIMENSION)
366      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
367		    (long) cinfo->max_v_samp_factor);
368    /* Mark component needed, until color conversion says otherwise */
369    compptr->component_needed = TRUE;
370    /* Mark no quantization table yet saved for component */
371    compptr->quant_table = NULL;
372  }
373
374  /* Compute number of fully interleaved MCU rows. */
375  cinfo->total_iMCU_rows = (JDIMENSION)
376    jdiv_round_up((long) cinfo->image_height,
377	          (long) (cinfo->max_v_samp_factor * cinfo->block_size));
378
379  /* Decide whether file contains multiple scans */
380  if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
381    cinfo->inputctl->has_multiple_scans = TRUE;
382  else
383    cinfo->inputctl->has_multiple_scans = FALSE;
384}
385
386
387LOCAL(void)
388per_scan_setup (j_decompress_ptr cinfo)
389/* Do computations that are needed before processing a JPEG scan */
390/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
391{
392  int ci, mcublks, tmp;
393  jpeg_component_info *compptr;
394  
395  if (cinfo->comps_in_scan == 1) {
396    
397    /* Noninterleaved (single-component) scan */
398    compptr = cinfo->cur_comp_info[0];
399    
400    /* Overall image size in MCUs */
401    cinfo->MCUs_per_row = compptr->width_in_blocks;
402    cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
403    
404    /* For noninterleaved scan, always one block per MCU */
405    compptr->MCU_width = 1;
406    compptr->MCU_height = 1;
407    compptr->MCU_blocks = 1;
408    compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
409    compptr->last_col_width = 1;
410    /* For noninterleaved scans, it is convenient to define last_row_height
411     * as the number of block rows present in the last iMCU row.
412     */
413    tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
414    if (tmp == 0) tmp = compptr->v_samp_factor;
415    compptr->last_row_height = tmp;
416    
417    /* Prepare array describing MCU composition */
418    cinfo->blocks_in_MCU = 1;
419    cinfo->MCU_membership[0] = 0;
420    
421  } else {
422    
423    /* Interleaved (multi-component) scan */
424    if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
425      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
426	       MAX_COMPS_IN_SCAN);
427    
428    /* Overall image size in MCUs */
429    cinfo->MCUs_per_row = (JDIMENSION)
430      jdiv_round_up((long) cinfo->image_width,
431		    (long) (cinfo->max_h_samp_factor * cinfo->block_size));
432    cinfo->MCU_rows_in_scan = (JDIMENSION)
433      jdiv_round_up((long) cinfo->image_height,
434		    (long) (cinfo->max_v_samp_factor * cinfo->block_size));
435    
436    cinfo->blocks_in_MCU = 0;
437    
438    for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
439      compptr = cinfo->cur_comp_info[ci];
440      /* Sampling factors give # of blocks of component in each MCU */
441      compptr->MCU_width = compptr->h_samp_factor;
442      compptr->MCU_height = compptr->v_samp_factor;
443      compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
444      compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
445      /* Figure number of non-dummy blocks in last MCU column & row */
446      tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
447      if (tmp == 0) tmp = compptr->MCU_width;
448      compptr->last_col_width = tmp;
449      tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
450      if (tmp == 0) tmp = compptr->MCU_height;
451      compptr->last_row_height = tmp;
452      /* Prepare array describing MCU composition */
453      mcublks = compptr->MCU_blocks;
454      if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
455	ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
456      while (mcublks-- > 0) {
457	cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
458      }
459    }
460    
461  }
462}
463
464
465/*
466 * Save away a copy of the Q-table referenced by each component present
467 * in the current scan, unless already saved during a prior scan.
468 *
469 * In a multiple-scan JPEG file, the encoder could assign different components
470 * the same Q-table slot number, but change table definitions between scans
471 * so that each component uses a different Q-table.  (The IJG encoder is not
472 * currently capable of doing this, but other encoders might.)  Since we want
473 * to be able to dequantize all the components at the end of the file, this
474 * means that we have to save away the table actually used for each component.
475 * We do this by copying the table at the start of the first scan containing
476 * the component.
477 * The JPEG spec prohibits the encoder from changing the contents of a Q-table
478 * slot between scans of a component using that slot.  If the encoder does so
479 * anyway, this decoder will simply use the Q-table values that were current
480 * at the start of the first scan for the component.
481 *
482 * The decompressor output side looks only at the saved quant tables,
483 * not at the current Q-table slots.
484 */
485
486LOCAL(void)
487latch_quant_tables (j_decompress_ptr cinfo)
488{
489  int ci, qtblno;
490  jpeg_component_info *compptr;
491  JQUANT_TBL * qtbl;
492
493  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
494    compptr = cinfo->cur_comp_info[ci];
495    /* No work if we already saved Q-table for this component */
496    if (compptr->quant_table != NULL)
497      continue;
498    /* Make sure specified quantization table is present */
499    qtblno = compptr->quant_tbl_no;
500    if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
501	cinfo->quant_tbl_ptrs[qtblno] == NULL)
502      ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
503    /* OK, save away the quantization table */
504    qtbl = (JQUANT_TBL *)
505      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
506				  SIZEOF(JQUANT_TBL));
507    MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
508    compptr->quant_table = qtbl;
509  }
510}
511
512
513/*
514 * Initialize the input modules to read a scan of compressed data.
515 * The first call to this is done by jdmaster.c after initializing
516 * the entire decompressor (during jpeg_start_decompress).
517 * Subsequent calls come from consume_markers, below.
518 */
519
520METHODDEF(void)
521start_input_pass (j_decompress_ptr cinfo)
522{
523  per_scan_setup(cinfo);
524  latch_quant_tables(cinfo);
525  (*cinfo->entropy->start_pass) (cinfo);
526  (*cinfo->coef->start_input_pass) (cinfo);
527  cinfo->inputctl->consume_input = cinfo->coef->consume_data;
528}
529
530
531/*
532 * Finish up after inputting a compressed-data scan.
533 * This is called by the coefficient controller after it's read all
534 * the expected data of the scan.
535 */
536
537METHODDEF(void)
538finish_input_pass (j_decompress_ptr cinfo)
539{
540  cinfo->inputctl->consume_input = consume_markers;
541}
542
543
544/*
545 * Read JPEG markers before, between, or after compressed-data scans.
546 * Change state as necessary when a new scan is reached.
547 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
548 *
549 * The consume_input method pointer points either here or to the
550 * coefficient controller's consume_data routine, depending on whether
551 * we are reading a compressed data segment or inter-segment markers.
552 *
553 * Note: This function should NOT return a pseudo SOS marker (with zero
554 * component number) to the caller.  A pseudo marker received by
555 * read_markers is processed and then skipped for other markers.
556 */
557
558METHODDEF(int)
559consume_markers (j_decompress_ptr cinfo)
560{
561  my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
562  int val;
563
564  if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
565    return JPEG_REACHED_EOI;
566
567  for (;;) {			/* Loop to pass pseudo SOS marker */
568    val = (*cinfo->marker->read_markers) (cinfo);
569
570    switch (val) {
571    case JPEG_REACHED_SOS:	/* Found SOS */
572      if (inputctl->inheaders) { /* 1st SOS */
573	if (inputctl->inheaders == 1)
574	  initial_setup(cinfo);
575	if (cinfo->comps_in_scan == 0) { /* pseudo SOS marker */
576	  inputctl->inheaders = 2;
577	  break;
578	}
579	inputctl->inheaders = 0;
580	/* Note: start_input_pass must be called by jdmaster.c
581	 * before any more input can be consumed.  jdapimin.c is
582	 * responsible for enforcing this sequencing.
583	 */
584      } else {			/* 2nd or later SOS marker */
585	if (! inputctl->pub.has_multiple_scans)
586	  ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
587	if (cinfo->comps_in_scan == 0) /* unexpected pseudo SOS marker */
588	  break;
589	start_input_pass(cinfo);
590      }
591      return val;
592    case JPEG_REACHED_EOI:	/* Found EOI */
593      inputctl->pub.eoi_reached = TRUE;
594      if (inputctl->inheaders) { /* Tables-only datastream, apparently */
595	if (cinfo->marker->saw_SOF)
596	  ERREXIT(cinfo, JERR_SOF_NO_SOS);
597      } else {
598	/* Prevent infinite loop in coef ctlr's decompress_data routine
599	 * if user set output_scan_number larger than number of scans.
600	 */
601	if (cinfo->output_scan_number > cinfo->input_scan_number)
602	  cinfo->output_scan_number = cinfo->input_scan_number;
603      }
604      return val;
605    case JPEG_SUSPENDED:
606      return val;
607    default:
608      return val;
609    }
610  }
611}
612
613
614/*
615 * Reset state to begin a fresh datastream.
616 */
617
618METHODDEF(void)
619reset_input_controller (j_decompress_ptr cinfo)
620{
621  my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
622
623  inputctl->pub.consume_input = consume_markers;
624  inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
625  inputctl->pub.eoi_reached = FALSE;
626  inputctl->inheaders = 1;
627  /* Reset other modules */
628  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
629  (*cinfo->marker->reset_marker_reader) (cinfo);
630  /* Reset progression state -- would be cleaner if entropy decoder did this */
631  cinfo->coef_bits = NULL;
632}
633
634
635/*
636 * Initialize the input controller module.
637 * This is called only once, when the decompression object is created.
638 */
639
640GLOBAL(void)
641jinit_input_controller (j_decompress_ptr cinfo)
642{
643  my_inputctl_ptr inputctl;
644
645  /* Create subobject in permanent pool */
646  inputctl = (my_inputctl_ptr)
647    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
648				SIZEOF(my_input_controller));
649  cinfo->inputctl = (struct jpeg_input_controller *) inputctl;
650  /* Initialize method pointers */
651  inputctl->pub.consume_input = consume_markers;
652  inputctl->pub.reset_input_controller = reset_input_controller;
653  inputctl->pub.start_input_pass = start_input_pass;
654  inputctl->pub.finish_input_pass = finish_input_pass;
655  /* Initialize state: can't use reset_input_controller since we don't
656   * want to try to reset other modules yet.
657   */
658  inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
659  inputctl->pub.eoi_reached = FALSE;
660  inputctl->inheaders = 1;
661}