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