1 /*
2 * jdinput.c
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * Modified 2002-2013 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
22 typedef struct {
23 struct jpeg_input_controller pub; /* public fields */
24
25 int inheaders; /* Nonzero until first SOS is reached */
26 } my_input_controller;
27
28 typedef my_input_controller * my_inputctl_ptr;
29
30
31 /* Forward declarations */
32 METHODDEF(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
46 GLOBAL(void)
47 jpeg_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 /* initial_setup 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
207 LOCAL(void)
208 initial_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 /* Only 8 to 12 bits data precision are supported for DCT based JPEG */
220 if (cinfo->data_precision < 8 || cinfo->data_precision > 12)
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
387 LOCAL(void)
388 per_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
486 LOCAL(void)
487 latch_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
520 METHODDEF(void)
521 start_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
537 METHODDEF(void)
538 finish_input_pass (j_decompress_ptr cinfo)
539 {
540 (*cinfo->entropy->finish_pass) (cinfo);
541 cinfo->inputctl->consume_input = consume_markers;
542 }
543
544
545 /*
546 * Read JPEG markers before, between, or after compressed-data scans.
547 * Change state as necessary when a new scan is reached.
548 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
549 *
550 * The consume_input method pointer points either here or to the
551 * coefficient controller's consume_data routine, depending on whether
552 * we are reading a compressed data segment or inter-segment markers.
553 *
554 * Note: This function should NOT return a pseudo SOS marker (with zero
555 * component number) to the caller. A pseudo marker received by
556 * read_markers is processed and then skipped for other markers.
557 */
558
559 METHODDEF(int)
560 consume_markers (j_decompress_ptr cinfo)
561 {
562 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
563 int val;
564
565 if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
566 return JPEG_REACHED_EOI;
567
568 for (;;) { /* Loop to pass pseudo SOS marker */
569 val = (*cinfo->marker->read_markers) (cinfo);
570
571 switch (val) {
572 case JPEG_REACHED_SOS: /* Found SOS */
573 if (inputctl->inheaders) { /* 1st SOS */
574 if (inputctl->inheaders == 1)
575 initial_setup(cinfo);
576 if (cinfo->comps_in_scan == 0) { /* pseudo SOS marker */
577 inputctl->inheaders = 2;
578 break;
579 }
580 inputctl->inheaders = 0;
581 /* Note: start_input_pass must be called by jdmaster.c
582 * before any more input can be consumed. jdapimin.c is
583 * responsible for enforcing this sequencing.
584 */
585 } else { /* 2nd or later SOS marker */
586 if (! inputctl->pub.has_multiple_scans)
587 ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
588 if (cinfo->comps_in_scan == 0) /* unexpected pseudo SOS marker */
589 break;
590 start_input_pass(cinfo);
591 }
592 return val;
593 case JPEG_REACHED_EOI: /* Found EOI */
594 inputctl->pub.eoi_reached = TRUE;
595 if (inputctl->inheaders) { /* Tables-only datastream, apparently */
596 if (cinfo->marker->saw_SOF)
597 ERREXIT(cinfo, JERR_SOF_NO_SOS);
598 } else {
599 /* Prevent infinite loop in coef ctlr's decompress_data routine
600 * if user set output_scan_number larger than number of scans.
601 */
602 if (cinfo->output_scan_number > cinfo->input_scan_number)
603 cinfo->output_scan_number = cinfo->input_scan_number;
604 }
605 return val;
606 case JPEG_SUSPENDED:
607 return val;
608 default:
609 return val;
610 }
611 }
612 }
613
614
615 /*
616 * Reset state to begin a fresh datastream.
617 */
618
619 METHODDEF(void)
620 reset_input_controller (j_decompress_ptr cinfo)
621 {
622 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl;
623
624 inputctl->pub.consume_input = consume_markers;
625 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
626 inputctl->pub.eoi_reached = FALSE;
627 inputctl->inheaders = 1;
628 /* Reset other modules */
629 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
630 (*cinfo->marker->reset_marker_reader) (cinfo);
631 /* Reset progression state -- would be cleaner if entropy decoder did this */
632 cinfo->coef_bits = NULL;
633 }
634
635
636 /*
637 * Initialize the input controller module.
638 * This is called only once, when the decompression object is created.
639 */
640
641 GLOBAL(void)
642 jinit_input_controller (j_decompress_ptr cinfo)
643 {
644 my_inputctl_ptr inputctl;
645
646 /* Create subobject in permanent pool */
647 inputctl = (my_inputctl_ptr)
648 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
649 SIZEOF(my_input_controller));
650 cinfo->inputctl = &inputctl->pub;
651 /* Initialize method pointers */
652 inputctl->pub.consume_input = consume_markers;
653 inputctl->pub.reset_input_controller = reset_input_controller;
654 inputctl->pub.start_input_pass = start_input_pass;
655 inputctl->pub.finish_input_pass = finish_input_pass;
656 /* Initialize state: can't use reset_input_controller since we don't
657 * want to try to reset other modules yet.
658 */
659 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
660 inputctl->pub.eoi_reached = FALSE;
661 inputctl->inheaders = 1;
662 }