1 /*
2 * jcmaster.c
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * Modified 2003-2017 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 master control logic for the JPEG compressor.
10 * These routines are concerned with parameter validation, initial setup,
11 * and inter-pass control (determining the number of passes and the work
12 * to be done in each pass).
13 */
14
15 #define JPEG_INTERNALS
16 #include "jinclude.h"
17 #include "jpeglib.h"
18
19
20 /* Private state */
21
22 typedef enum {
23 main_pass, /* input data, also do first output step */
24 huff_opt_pass, /* Huffman code optimization pass */
25 output_pass /* data output pass */
26 } c_pass_type;
27
28 typedef struct {
29 struct jpeg_comp_master pub; /* public fields */
30
31 c_pass_type pass_type; /* the type of the current pass */
32
33 int pass_number; /* # of passes completed */
34 int total_passes; /* total # of passes needed */
35
36 int scan_number; /* current index in scan_info[] */
37 } my_comp_master;
38
39 typedef my_comp_master * my_master_ptr;
40
41
42 /*
43 * Support routines that do various essential calculations.
44 */
45
46 LOCAL(void)
47 initial_setup (j_compress_ptr cinfo)
48 /* Do computations that are needed before master selection phase */
49 {
50 int ci, ssize;
51 jpeg_component_info *compptr;
52
53 /* Sanity check on block_size */
54 if (cinfo->block_size < 1 || cinfo->block_size > 16)
55 ERREXIT2(cinfo, JERR_BAD_DCTSIZE, cinfo->block_size, cinfo->block_size);
56
57 /* Derive natural_order from block_size */
58 switch (cinfo->block_size) {
59 case 2: cinfo->natural_order = jpeg_natural_order2; break;
60 case 3: cinfo->natural_order = jpeg_natural_order3; break;
61 case 4: cinfo->natural_order = jpeg_natural_order4; break;
62 case 5: cinfo->natural_order = jpeg_natural_order5; break;
63 case 6: cinfo->natural_order = jpeg_natural_order6; break;
64 case 7: cinfo->natural_order = jpeg_natural_order7; break;
65 default: cinfo->natural_order = jpeg_natural_order; break;
66 }
67
68 /* Derive lim_Se from block_size */
69 cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
70 cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
71
72 /* Sanity check on image dimensions */
73 if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
74 cinfo->num_components <= 0)
75 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
76
77 /* Make sure image isn't bigger than I can handle */
78 if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
79 (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
80 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
81
82 /* Only 8 to 12 bits data precision are supported for DCT based JPEG */
83 if (cinfo->data_precision < 8 || cinfo->data_precision > 12)
84 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
85
86 /* Check that number of components won't exceed internal array sizes */
87 if (cinfo->num_components > MAX_COMPONENTS)
88 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
89 MAX_COMPONENTS);
90
91 /* Compute maximum sampling factors; check factor validity */
92 cinfo->max_h_samp_factor = 1;
93 cinfo->max_v_samp_factor = 1;
94 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
95 ci++, compptr++) {
96 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
97 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
98 ERREXIT(cinfo, JERR_BAD_SAMPLING);
99 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
100 compptr->h_samp_factor);
101 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
102 compptr->v_samp_factor);
103 }
104
105 /* Compute dimensions of components */
106 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
107 ci++, compptr++) {
108 /* Fill in the correct component_index value; don't rely on application */
109 compptr->component_index = ci;
110 /* In selecting the actual DCT scaling for each component, we try to
111 * scale down the chroma components via DCT scaling rather than downsampling.
112 * This saves time if the downsampler gets to use 1:1 scaling.
113 * Note this code adapts subsampling ratios which are powers of 2.
114 */
115 ssize = 1;
116 #ifdef DCT_SCALING_SUPPORTED
117 while (cinfo->min_DCT_h_scaled_size * ssize <=
118 (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
119 (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
120 ssize = ssize * 2;
121 }
122 #endif
123 compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
124 ssize = 1;
125 #ifdef DCT_SCALING_SUPPORTED
126 while (cinfo->min_DCT_v_scaled_size * ssize <=
127 (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
128 (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
129 ssize = ssize * 2;
130 }
131 #endif
132 compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
133
134 /* We don't support DCT ratios larger than 2. */
135 if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
136 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
137 else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
138 compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
139
140 /* Size in DCT blocks */
141 compptr->width_in_blocks = (JDIMENSION)
142 jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
143 (long) (cinfo->max_h_samp_factor * cinfo->block_size));
144 compptr->height_in_blocks = (JDIMENSION)
145 jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
146 (long) (cinfo->max_v_samp_factor * cinfo->block_size));
147 /* Size in samples */
148 compptr->downsampled_width = (JDIMENSION)
149 jdiv_round_up((long) cinfo->jpeg_width *
150 (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
151 (long) (cinfo->max_h_samp_factor * cinfo->block_size));
152 compptr->downsampled_height = (JDIMENSION)
153 jdiv_round_up((long) cinfo->jpeg_height *
154 (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
155 (long) (cinfo->max_v_samp_factor * cinfo->block_size));
156 /* Don't need quantization scale after DCT,
157 * until color conversion says otherwise.
158 */
159 compptr->component_needed = FALSE;
160 }
161
162 /* Compute number of fully interleaved MCU rows (number of times that
163 * main controller will call coefficient controller).
164 */
165 cinfo->total_iMCU_rows = (JDIMENSION)
166 jdiv_round_up((long) cinfo->jpeg_height,
167 (long) (cinfo->max_v_samp_factor * cinfo->block_size));
168 }
169
170
171 #ifdef C_MULTISCAN_FILES_SUPPORTED
172
173 LOCAL(void)
174 validate_script (j_compress_ptr cinfo)
175 /* Verify that the scan script in cinfo->scan_info[] is valid; also
176 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
177 */
178 {
179 const jpeg_scan_info * scanptr;
180 int scanno, ncomps, ci, coefi, thisi;
181 int Ss, Se, Ah, Al;
182 boolean component_sent[MAX_COMPONENTS];
183 #ifdef C_PROGRESSIVE_SUPPORTED
184 int * last_bitpos_ptr;
185 int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
186 /* -1 until that coefficient has been seen; then last Al for it */
187 #endif
188
189 if (cinfo->num_scans <= 0)
190 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
191
192 /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
193 * for progressive JPEG, no scan can have this.
194 */
195 scanptr = cinfo->scan_info;
196 if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
197 #ifdef C_PROGRESSIVE_SUPPORTED
198 cinfo->progressive_mode = TRUE;
199 last_bitpos_ptr = & last_bitpos[0][0];
200 for (ci = 0; ci < cinfo->num_components; ci++)
201 for (coefi = 0; coefi < DCTSIZE2; coefi++)
202 *last_bitpos_ptr++ = -1;
203 #else
204 ERREXIT(cinfo, JERR_NOT_COMPILED);
205 #endif
206 } else {
207 cinfo->progressive_mode = FALSE;
208 for (ci = 0; ci < cinfo->num_components; ci++)
209 component_sent[ci] = FALSE;
210 }
211
212 for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
213 /* Validate component indexes */
214 ncomps = scanptr->comps_in_scan;
215 if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
216 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
217 for (ci = 0; ci < ncomps; ci++) {
218 thisi = scanptr->component_index[ci];
219 if (thisi < 0 || thisi >= cinfo->num_components)
220 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
221 /* Components must appear in SOF order within each scan */
222 if (ci > 0 && thisi <= scanptr->component_index[ci-1])
223 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
224 }
225 /* Validate progression parameters */
226 Ss = scanptr->Ss;
227 Se = scanptr->Se;
228 Ah = scanptr->Ah;
229 Al = scanptr->Al;
230 if (cinfo->progressive_mode) {
231 #ifdef C_PROGRESSIVE_SUPPORTED
232 /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
233 * seems wrong: the upper bound ought to depend on data precision.
234 * Perhaps they really meant 0..N+1 for N-bit precision.
235 * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
236 * out-of-range reconstructed DC values during the first DC scan,
237 * which might cause problems for some decoders.
238 */
239 if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
240 Ah < 0 || Ah > (cinfo->data_precision > 8 ? 13 : 10) ||
241 Al < 0 || Al > (cinfo->data_precision > 8 ? 13 : 10))
242 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
243 if (Ss == 0) {
244 if (Se != 0) /* DC and AC together not OK */
245 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
246 } else {
247 if (ncomps != 1) /* AC scans must be for only one component */
248 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
249 }
250 for (ci = 0; ci < ncomps; ci++) {
251 last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
252 if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
253 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
254 for (coefi = Ss; coefi <= Se; coefi++) {
255 if (last_bitpos_ptr[coefi] < 0) {
256 /* first scan of this coefficient */
257 if (Ah != 0)
258 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
259 } else {
260 /* not first scan */
261 if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
262 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
263 }
264 last_bitpos_ptr[coefi] = Al;
265 }
266 }
267 #endif
268 } else {
269 /* For sequential JPEG, all progression parameters must be these: */
270 if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
271 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
272 /* Make sure components are not sent twice */
273 for (ci = 0; ci < ncomps; ci++) {
274 thisi = scanptr->component_index[ci];
275 if (component_sent[thisi])
276 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
277 component_sent[thisi] = TRUE;
278 }
279 }
280 }
281
282 /* Now verify that everything got sent. */
283 if (cinfo->progressive_mode) {
284 #ifdef C_PROGRESSIVE_SUPPORTED
285 /* For progressive mode, we only check that at least some DC data
286 * got sent for each component; the spec does not require that all bits
287 * of all coefficients be transmitted. Would it be wiser to enforce
288 * transmission of all coefficient bits??
289 */
290 for (ci = 0; ci < cinfo->num_components; ci++) {
291 if (last_bitpos[ci][0] < 0)
292 ERREXIT(cinfo, JERR_MISSING_DATA);
293 }
294 #endif
295 } else {
296 for (ci = 0; ci < cinfo->num_components; ci++) {
297 if (! component_sent[ci])
298 ERREXIT(cinfo, JERR_MISSING_DATA);
299 }
300 }
301 }
302
303
304 LOCAL(void)
305 reduce_script (j_compress_ptr cinfo)
306 /* Adapt scan script for use with reduced block size;
307 * assume that script has been validated before.
308 */
309 {
310 jpeg_scan_info * scanptr;
311 int idxout, idxin;
312
313 /* Circumvent const declaration for this function */
314 scanptr = (jpeg_scan_info *) cinfo->scan_info;
315 idxout = 0;
316
317 for (idxin = 0; idxin < cinfo->num_scans; idxin++) {
318 /* After skipping, idxout becomes smaller than idxin */
319 if (idxin != idxout)
320 /* Copy rest of data;
321 * note we stay in given chunk of allocated memory.
322 */
323 scanptr[idxout] = scanptr[idxin];
324 if (scanptr[idxout].Ss > cinfo->lim_Se)
325 /* Entire scan out of range - skip this entry */
326 continue;
327 if (scanptr[idxout].Se > cinfo->lim_Se)
328 /* Limit scan to end of block */
329 scanptr[idxout].Se = cinfo->lim_Se;
330 idxout++;
331 }
332
333 cinfo->num_scans = idxout;
334 }
335
336 #endif /* C_MULTISCAN_FILES_SUPPORTED */
337
338
339 LOCAL(void)
340 select_scan_parameters (j_compress_ptr cinfo)
341 /* Set up the scan parameters for the current scan */
342 {
343 int ci;
344
345 #ifdef C_MULTISCAN_FILES_SUPPORTED
346 if (cinfo->scan_info != NULL) {
347 /* Prepare for current scan --- the script is already validated */
348 my_master_ptr master = (my_master_ptr) cinfo->master;
349 const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
350
351 cinfo->comps_in_scan = scanptr->comps_in_scan;
352 for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
353 cinfo->cur_comp_info[ci] =
354 &cinfo->comp_info[scanptr->component_index[ci]];
355 }
356 if (cinfo->progressive_mode) {
357 cinfo->Ss = scanptr->Ss;
358 cinfo->Se = scanptr->Se;
359 cinfo->Ah = scanptr->Ah;
360 cinfo->Al = scanptr->Al;
361 return;
362 }
363 }
364 else
365 #endif
366 {
367 /* Prepare for single sequential-JPEG scan containing all components */
368 if (cinfo->num_components > MAX_COMPS_IN_SCAN)
369 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
370 MAX_COMPS_IN_SCAN);
371 cinfo->comps_in_scan = cinfo->num_components;
372 for (ci = 0; ci < cinfo->num_components; ci++) {
373 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
374 }
375 }
376 cinfo->Ss = 0;
377 cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
378 cinfo->Ah = 0;
379 cinfo->Al = 0;
380 }
381
382
383 LOCAL(void)
384 per_scan_setup (j_compress_ptr cinfo)
385 /* Do computations that are needed before processing a JPEG scan */
386 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
387 {
388 int ci, mcublks, tmp;
389 jpeg_component_info *compptr;
390
391 if (cinfo->comps_in_scan == 1) {
392
393 /* Noninterleaved (single-component) scan */
394 compptr = cinfo->cur_comp_info[0];
395
396 /* Overall image size in MCUs */
397 cinfo->MCUs_per_row = compptr->width_in_blocks;
398 cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
399
400 /* For noninterleaved scan, always one block per MCU */
401 compptr->MCU_width = 1;
402 compptr->MCU_height = 1;
403 compptr->MCU_blocks = 1;
404 compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
405 compptr->last_col_width = 1;
406 /* For noninterleaved scans, it is convenient to define last_row_height
407 * as the number of block rows present in the last iMCU row.
408 */
409 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
410 if (tmp == 0) tmp = compptr->v_samp_factor;
411 compptr->last_row_height = tmp;
412
413 /* Prepare array describing MCU composition */
414 cinfo->blocks_in_MCU = 1;
415 cinfo->MCU_membership[0] = 0;
416
417 } else {
418
419 /* Interleaved (multi-component) scan */
420 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
421 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
422 MAX_COMPS_IN_SCAN);
423
424 /* Overall image size in MCUs */
425 cinfo->MCUs_per_row = (JDIMENSION)
426 jdiv_round_up((long) cinfo->jpeg_width,
427 (long) (cinfo->max_h_samp_factor * cinfo->block_size));
428 cinfo->MCU_rows_in_scan = (JDIMENSION)
429 jdiv_round_up((long) cinfo->jpeg_height,
430 (long) (cinfo->max_v_samp_factor * cinfo->block_size));
431
432 cinfo->blocks_in_MCU = 0;
433
434 for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
435 compptr = cinfo->cur_comp_info[ci];
436 /* Sampling factors give # of blocks of component in each MCU */
437 compptr->MCU_width = compptr->h_samp_factor;
438 compptr->MCU_height = compptr->v_samp_factor;
439 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
440 compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
441 /* Figure number of non-dummy blocks in last MCU column & row */
442 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
443 if (tmp == 0) tmp = compptr->MCU_width;
444 compptr->last_col_width = tmp;
445 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
446 if (tmp == 0) tmp = compptr->MCU_height;
447 compptr->last_row_height = tmp;
448 /* Prepare array describing MCU composition */
449 mcublks = compptr->MCU_blocks;
450 if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
451 ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
452 while (mcublks-- > 0) {
453 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
454 }
455 }
456
457 }
458
459 /* Convert restart specified in rows to actual MCU count. */
460 /* Note that count must fit in 16 bits, so we provide limiting. */
461 if (cinfo->restart_in_rows > 0) {
462 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
463 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
464 }
465 }
466
467
468 /*
469 * Per-pass setup.
470 * This is called at the beginning of each pass. We determine which modules
471 * will be active during this pass and give them appropriate start_pass calls.
472 * We also set is_last_pass to indicate whether any more passes will be
473 * required.
474 */
475
476 METHODDEF(void)
477 prepare_for_pass (j_compress_ptr cinfo)
478 {
479 my_master_ptr master = (my_master_ptr) cinfo->master;
480
481 switch (master->pass_type) {
482 case main_pass:
483 /* Initial pass: will collect input data, and do either Huffman
484 * optimization or data output for the first scan.
485 */
486 select_scan_parameters(cinfo);
487 per_scan_setup(cinfo);
488 if (! cinfo->raw_data_in) {
489 (*cinfo->cconvert->start_pass) (cinfo);
490 (*cinfo->downsample->start_pass) (cinfo);
491 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
492 }
493 (*cinfo->fdct->start_pass) (cinfo);
494 (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
495 (*cinfo->coef->start_pass) (cinfo,
496 (master->total_passes > 1 ?
497 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
498 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
499 if (cinfo->optimize_coding) {
500 /* No immediate data output; postpone writing frame/scan headers */
501 master->pub.call_pass_startup = FALSE;
502 } else {
503 /* Will write frame/scan headers at first jpeg_write_scanlines call */
504 master->pub.call_pass_startup = TRUE;
505 }
506 break;
507 #ifdef ENTROPY_OPT_SUPPORTED
508 case huff_opt_pass:
509 /* Do Huffman optimization for a scan after the first one. */
510 select_scan_parameters(cinfo);
511 per_scan_setup(cinfo);
512 if (cinfo->Ss != 0 || cinfo->Ah == 0) {
513 (*cinfo->entropy->start_pass) (cinfo, TRUE);
514 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
515 master->pub.call_pass_startup = FALSE;
516 break;
517 }
518 /* Special case: Huffman DC refinement scans need no Huffman table
519 * and therefore we can skip the optimization pass for them.
520 */
521 master->pass_type = output_pass;
522 master->pass_number++;
523 /*FALLTHROUGH*/
524 #endif
525 case output_pass:
526 /* Do a data-output pass. */
527 /* We need not repeat per-scan setup if prior optimization pass did it. */
528 if (! cinfo->optimize_coding) {
529 select_scan_parameters(cinfo);
530 per_scan_setup(cinfo);
531 }
532 (*cinfo->entropy->start_pass) (cinfo, FALSE);
533 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
534 /* We emit frame/scan headers now */
535 if (master->scan_number == 0)
536 (*cinfo->marker->write_frame_header) (cinfo);
537 (*cinfo->marker->write_scan_header) (cinfo);
538 master->pub.call_pass_startup = FALSE;
539 break;
540 default:
541 ERREXIT(cinfo, JERR_NOT_COMPILED);
542 }
543
544 master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
545
546 /* Set up progress monitor's pass info if present */
547 if (cinfo->progress != NULL) {
548 cinfo->progress->completed_passes = master->pass_number;
549 cinfo->progress->total_passes = master->total_passes;
550 }
551 }
552
553
554 /*
555 * Special start-of-pass hook.
556 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
557 * In single-pass processing, we need this hook because we don't want to
558 * write frame/scan headers during jpeg_start_compress; we want to let the
559 * application write COM markers etc. between jpeg_start_compress and the
560 * jpeg_write_scanlines loop.
561 * In multi-pass processing, this routine is not used.
562 */
563
564 METHODDEF(void)
565 pass_startup (j_compress_ptr cinfo)
566 {
567 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
568
569 (*cinfo->marker->write_frame_header) (cinfo);
570 (*cinfo->marker->write_scan_header) (cinfo);
571 }
572
573
574 /*
575 * Finish up at end of pass.
576 */
577
578 METHODDEF(void)
579 finish_pass_master (j_compress_ptr cinfo)
580 {
581 my_master_ptr master = (my_master_ptr) cinfo->master;
582
583 /* The entropy coder always needs an end-of-pass call,
584 * either to analyze statistics or to flush its output buffer.
585 */
586 (*cinfo->entropy->finish_pass) (cinfo);
587
588 /* Update state for next pass */
589 switch (master->pass_type) {
590 case main_pass:
591 /* next pass is either output of scan 0 (after optimization)
592 * or output of scan 1 (if no optimization).
593 */
594 master->pass_type = output_pass;
595 if (! cinfo->optimize_coding)
596 master->scan_number++;
597 break;
598 case huff_opt_pass:
599 /* next pass is always output of current scan */
600 master->pass_type = output_pass;
601 break;
602 case output_pass:
603 /* next pass is either optimization or output of next scan */
604 if (cinfo->optimize_coding)
605 master->pass_type = huff_opt_pass;
606 master->scan_number++;
607 break;
608 }
609
610 master->pass_number++;
611 }
612
613
614 /*
615 * Initialize master compression control.
616 */
617
618 GLOBAL(void)
619 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
620 {
621 my_master_ptr master;
622
623 master = (my_master_ptr)
624 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
625 SIZEOF(my_comp_master));
626 cinfo->master = &master->pub;
627 master->pub.prepare_for_pass = prepare_for_pass;
628 master->pub.pass_startup = pass_startup;
629 master->pub.finish_pass = finish_pass_master;
630 master->pub.is_last_pass = FALSE;
631
632 /* Validate parameters, determine derived values */
633 initial_setup(cinfo);
634
635 if (cinfo->scan_info != NULL) {
636 #ifdef C_MULTISCAN_FILES_SUPPORTED
637 validate_script(cinfo);
638 if (cinfo->block_size < DCTSIZE)
639 reduce_script(cinfo);
640 #else
641 ERREXIT(cinfo, JERR_NOT_COMPILED);
642 #endif
643 } else {
644 cinfo->progressive_mode = FALSE;
645 cinfo->num_scans = 1;
646 }
647
648 if (cinfo->optimize_coding)
649 cinfo->arith_code = FALSE; /* disable arithmetic coding */
650 else if (! cinfo->arith_code &&
651 (cinfo->progressive_mode ||
652 (cinfo->block_size > 1 && cinfo->block_size < DCTSIZE)))
653 /* TEMPORARY HACK ??? */
654 /* assume default tables no good for progressive or reduced AC mode */
655 cinfo->optimize_coding = TRUE; /* force Huffman optimization */
656
657 /* Initialize my private state */
658 if (transcode_only) {
659 /* no main pass in transcoding */
660 if (cinfo->optimize_coding)
661 master->pass_type = huff_opt_pass;
662 else
663 master->pass_type = output_pass;
664 } else {
665 /* for normal compression, first pass is always this type: */
666 master->pass_type = main_pass;
667 }
668 master->scan_number = 0;
669 master->pass_number = 0;
670 if (cinfo->optimize_coding)
671 master->total_passes = cinfo->num_scans * 2;
672 else
673 master->total_passes = cinfo->num_scans;
674 }