source: trunk/libjpeg/jcmaster.c @ 15

Last change on this file since 15 was 15, checked in by Eugene Romanenko, 15 years ago

needed libs update

File size: 20.0 KB
Line 
1/*
2 * jcmaster.c
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains master control logic for the JPEG compressor.
9 * These routines are concerned with parameter validation, initial setup,
10 * and inter-pass control (determining the number of passes and the work
11 * to be done in each pass).
12 */
13
14#define JPEG_INTERNALS
15#include "jinclude.h"
16#include "jpeglib.h"
17
18
19/* Private state */
20
21typedef enum {
22        main_pass,              /* input data, also do first output step */
23        huff_opt_pass,          /* Huffman code optimization pass */
24        output_pass             /* data output pass */
25} c_pass_type;
26
27typedef struct {
28  struct jpeg_comp_master pub;  /* public fields */
29
30  c_pass_type pass_type;        /* the type of the current pass */
31
32  int pass_number;              /* # of passes completed */
33  int total_passes;             /* total # of passes needed */
34
35  int scan_number;              /* current index in scan_info[] */
36} my_comp_master;
37
38typedef my_comp_master * my_master_ptr;
39
40
41/*
42 * Support routines that do various essential calculations.
43 */
44
45LOCAL(void)
46initial_setup (j_compress_ptr cinfo)
47/* Do computations that are needed before master selection phase */
48{
49  int ci;
50  jpeg_component_info *compptr;
51  long samplesperrow;
52  JDIMENSION jd_samplesperrow;
53
54  /* Sanity check on image dimensions */
55  if (cinfo->image_height <= 0 || cinfo->image_width <= 0
56      || cinfo->num_components <= 0 || cinfo->input_components <= 0)
57    ERREXIT(cinfo, JERR_EMPTY_IMAGE);
58
59  /* Make sure image isn't bigger than I can handle */
60  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
61      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
62    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
63
64  /* Width of an input scanline must be representable as JDIMENSION. */
65  samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
66  jd_samplesperrow = (JDIMENSION) samplesperrow;
67  if ((long) jd_samplesperrow != samplesperrow)
68    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
69
70  /* For now, precision must match compiled-in value... */
71  if (cinfo->data_precision != BITS_IN_JSAMPLE)
72    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
73
74  /* Check that number of components won't exceed internal array sizes */
75  if (cinfo->num_components > MAX_COMPONENTS)
76    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
77             MAX_COMPONENTS);
78
79  /* Compute maximum sampling factors; check factor validity */
80  cinfo->max_h_samp_factor = 1;
81  cinfo->max_v_samp_factor = 1;
82  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
83       ci++, compptr++) {
84    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
85        compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
86      ERREXIT(cinfo, JERR_BAD_SAMPLING);
87    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
88                                   compptr->h_samp_factor);
89    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
90                                   compptr->v_samp_factor);
91  }
92
93  /* Compute dimensions of components */
94  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
95       ci++, compptr++) {
96    /* Fill in the correct component_index value; don't rely on application */
97    compptr->component_index = ci;
98    /* For compression, we never do DCT scaling. */
99    compptr->DCT_scaled_size = DCTSIZE;
100    /* Size in DCT blocks */
101    compptr->width_in_blocks = (JDIMENSION)
102      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
103                    (long) (cinfo->max_h_samp_factor * DCTSIZE));
104    compptr->height_in_blocks = (JDIMENSION)
105      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
106                    (long) (cinfo->max_v_samp_factor * DCTSIZE));
107    /* Size in samples */
108    compptr->downsampled_width = (JDIMENSION)
109      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
110                    (long) cinfo->max_h_samp_factor);
111    compptr->downsampled_height = (JDIMENSION)
112      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
113                    (long) cinfo->max_v_samp_factor);
114    /* Mark component needed (this flag isn't actually used for compression) */
115    compptr->component_needed = TRUE;
116  }
117
118  /* Compute number of fully interleaved MCU rows (number of times that
119   * main controller will call coefficient controller).
120   */
121  cinfo->total_iMCU_rows = (JDIMENSION)
122    jdiv_round_up((long) cinfo->image_height,
123                  (long) (cinfo->max_v_samp_factor*DCTSIZE));
124}
125
126
127#ifdef C_MULTISCAN_FILES_SUPPORTED
128
129LOCAL(void)
130validate_script (j_compress_ptr cinfo)
131/* Verify that the scan script in cinfo->scan_info[] is valid; also
132 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
133 */
134{
135  const jpeg_scan_info * scanptr;
136  int scanno, ncomps, ci, coefi, thisi;
137  int Ss, Se, Ah, Al;
138  boolean component_sent[MAX_COMPONENTS];
139#ifdef C_PROGRESSIVE_SUPPORTED
140  int * last_bitpos_ptr;
141  int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
142  /* -1 until that coefficient has been seen; then last Al for it */
143#endif
144
145  if (cinfo->num_scans <= 0)
146    ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
147
148  /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
149   * for progressive JPEG, no scan can have this.
150   */
151  scanptr = cinfo->scan_info;
152  if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
153#ifdef C_PROGRESSIVE_SUPPORTED
154    cinfo->progressive_mode = TRUE;
155    last_bitpos_ptr = & last_bitpos[0][0];
156    for (ci = 0; ci < cinfo->num_components; ci++) 
157      for (coefi = 0; coefi < DCTSIZE2; coefi++)
158        *last_bitpos_ptr++ = -1;
159#else
160    ERREXIT(cinfo, JERR_NOT_COMPILED);
161#endif
162  } else {
163    cinfo->progressive_mode = FALSE;
164    for (ci = 0; ci < cinfo->num_components; ci++) 
165      component_sent[ci] = FALSE;
166  }
167
168  for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
169    /* Validate component indexes */
170    ncomps = scanptr->comps_in_scan;
171    if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
172      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
173    for (ci = 0; ci < ncomps; ci++) {
174      thisi = scanptr->component_index[ci];
175      if (thisi < 0 || thisi >= cinfo->num_components)
176        ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
177      /* Components must appear in SOF order within each scan */
178      if (ci > 0 && thisi <= scanptr->component_index[ci-1])
179        ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
180    }
181    /* Validate progression parameters */
182    Ss = scanptr->Ss;
183    Se = scanptr->Se;
184    Ah = scanptr->Ah;
185    Al = scanptr->Al;
186    if (cinfo->progressive_mode) {
187#ifdef C_PROGRESSIVE_SUPPORTED
188      /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
189       * seems wrong: the upper bound ought to depend on data precision.
190       * Perhaps they really meant 0..N+1 for N-bit precision.
191       * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
192       * out-of-range reconstructed DC values during the first DC scan,
193       * which might cause problems for some decoders.
194       */
195#if BITS_IN_JSAMPLE == 8
196#define MAX_AH_AL 10
197#else
198#define MAX_AH_AL 13
199#endif
200      if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
201          Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
202        ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
203      if (Ss == 0) {
204        if (Se != 0)            /* DC and AC together not OK */
205          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
206      } else {
207        if (ncomps != 1)        /* AC scans must be for only one component */
208          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
209      }
210      for (ci = 0; ci < ncomps; ci++) {
211        last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
212        if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
213          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
214        for (coefi = Ss; coefi <= Se; coefi++) {
215          if (last_bitpos_ptr[coefi] < 0) {
216            /* first scan of this coefficient */
217            if (Ah != 0)
218              ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
219          } else {
220            /* not first scan */
221            if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
222              ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
223          }
224          last_bitpos_ptr[coefi] = Al;
225        }
226      }
227#endif
228    } else {
229      /* For sequential JPEG, all progression parameters must be these: */
230      if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
231        ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
232      /* Make sure components are not sent twice */
233      for (ci = 0; ci < ncomps; ci++) {
234        thisi = scanptr->component_index[ci];
235        if (component_sent[thisi])
236          ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
237        component_sent[thisi] = TRUE;
238      }
239    }
240  }
241
242  /* Now verify that everything got sent. */
243  if (cinfo->progressive_mode) {
244#ifdef C_PROGRESSIVE_SUPPORTED
245    /* For progressive mode, we only check that at least some DC data
246     * got sent for each component; the spec does not require that all bits
247     * of all coefficients be transmitted.  Would it be wiser to enforce
248     * transmission of all coefficient bits??
249     */
250    for (ci = 0; ci < cinfo->num_components; ci++) {
251      if (last_bitpos[ci][0] < 0)
252        ERREXIT(cinfo, JERR_MISSING_DATA);
253    }
254#endif
255  } else {
256    for (ci = 0; ci < cinfo->num_components; ci++) {
257      if (! component_sent[ci])
258        ERREXIT(cinfo, JERR_MISSING_DATA);
259    }
260  }
261}
262
263#endif /* C_MULTISCAN_FILES_SUPPORTED */
264
265
266LOCAL(void)
267select_scan_parameters (j_compress_ptr cinfo)
268/* Set up the scan parameters for the current scan */
269{
270  int ci;
271
272#ifdef C_MULTISCAN_FILES_SUPPORTED
273  if (cinfo->scan_info != NULL) {
274    /* Prepare for current scan --- the script is already validated */
275    my_master_ptr master = (my_master_ptr) cinfo->master;
276    const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
277
278    cinfo->comps_in_scan = scanptr->comps_in_scan;
279    for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
280      cinfo->cur_comp_info[ci] =
281        &cinfo->comp_info[scanptr->component_index[ci]];
282    }
283    cinfo->Ss = scanptr->Ss;
284    cinfo->Se = scanptr->Se;
285    cinfo->Ah = scanptr->Ah;
286    cinfo->Al = scanptr->Al;
287  }
288  else
289#endif
290  {
291    /* Prepare for single sequential-JPEG scan containing all components */
292    if (cinfo->num_components > MAX_COMPS_IN_SCAN)
293      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
294               MAX_COMPS_IN_SCAN);
295    cinfo->comps_in_scan = cinfo->num_components;
296    for (ci = 0; ci < cinfo->num_components; ci++) {
297      cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
298    }
299    cinfo->Ss = 0;
300    cinfo->Se = DCTSIZE2-1;
301    cinfo->Ah = 0;
302    cinfo->Al = 0;
303  }
304}
305
306
307LOCAL(void)
308per_scan_setup (j_compress_ptr cinfo)
309/* Do computations that are needed before processing a JPEG scan */
310/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
311{
312  int ci, mcublks, tmp;
313  jpeg_component_info *compptr;
314 
315  if (cinfo->comps_in_scan == 1) {
316   
317    /* Noninterleaved (single-component) scan */
318    compptr = cinfo->cur_comp_info[0];
319   
320    /* Overall image size in MCUs */
321    cinfo->MCUs_per_row = compptr->width_in_blocks;
322    cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
323   
324    /* For noninterleaved scan, always one block per MCU */
325    compptr->MCU_width = 1;
326    compptr->MCU_height = 1;
327    compptr->MCU_blocks = 1;
328    compptr->MCU_sample_width = DCTSIZE;
329    compptr->last_col_width = 1;
330    /* For noninterleaved scans, it is convenient to define last_row_height
331     * as the number of block rows present in the last iMCU row.
332     */
333    tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
334    if (tmp == 0) tmp = compptr->v_samp_factor;
335    compptr->last_row_height = tmp;
336   
337    /* Prepare array describing MCU composition */
338    cinfo->blocks_in_MCU = 1;
339    cinfo->MCU_membership[0] = 0;
340   
341  } else {
342   
343    /* Interleaved (multi-component) scan */
344    if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
345      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
346               MAX_COMPS_IN_SCAN);
347   
348    /* Overall image size in MCUs */
349    cinfo->MCUs_per_row = (JDIMENSION)
350      jdiv_round_up((long) cinfo->image_width,
351                    (long) (cinfo->max_h_samp_factor*DCTSIZE));
352    cinfo->MCU_rows_in_scan = (JDIMENSION)
353      jdiv_round_up((long) cinfo->image_height,
354                    (long) (cinfo->max_v_samp_factor*DCTSIZE));
355   
356    cinfo->blocks_in_MCU = 0;
357   
358    for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
359      compptr = cinfo->cur_comp_info[ci];
360      /* Sampling factors give # of blocks of component in each MCU */
361      compptr->MCU_width = compptr->h_samp_factor;
362      compptr->MCU_height = compptr->v_samp_factor;
363      compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
364      compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
365      /* Figure number of non-dummy blocks in last MCU column & row */
366      tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
367      if (tmp == 0) tmp = compptr->MCU_width;
368      compptr->last_col_width = tmp;
369      tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
370      if (tmp == 0) tmp = compptr->MCU_height;
371      compptr->last_row_height = tmp;
372      /* Prepare array describing MCU composition */
373      mcublks = compptr->MCU_blocks;
374      if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
375        ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
376      while (mcublks-- > 0) {
377        cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
378      }
379    }
380   
381  }
382
383  /* Convert restart specified in rows to actual MCU count. */
384  /* Note that count must fit in 16 bits, so we provide limiting. */
385  if (cinfo->restart_in_rows > 0) {
386    long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
387    cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
388  }
389}
390
391
392/*
393 * Per-pass setup.
394 * This is called at the beginning of each pass.  We determine which modules
395 * will be active during this pass and give them appropriate start_pass calls.
396 * We also set is_last_pass to indicate whether any more passes will be
397 * required.
398 */
399
400METHODDEF(void)
401prepare_for_pass (j_compress_ptr cinfo)
402{
403  my_master_ptr master = (my_master_ptr) cinfo->master;
404
405  switch (master->pass_type) {
406  case main_pass:
407    /* Initial pass: will collect input data, and do either Huffman
408     * optimization or data output for the first scan.
409     */
410    select_scan_parameters(cinfo);
411    per_scan_setup(cinfo);
412    if (! cinfo->raw_data_in) {
413      (*cinfo->cconvert->start_pass) (cinfo);
414      (*cinfo->downsample->start_pass) (cinfo);
415      (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
416    }
417    (*cinfo->fdct->start_pass) (cinfo);
418    (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
419    (*cinfo->coef->start_pass) (cinfo,
420                                (master->total_passes > 1 ?
421                                 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
422    (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
423    if (cinfo->optimize_coding) {
424      /* No immediate data output; postpone writing frame/scan headers */
425      master->pub.call_pass_startup = FALSE;
426    } else {
427      /* Will write frame/scan headers at first jpeg_write_scanlines call */
428      master->pub.call_pass_startup = TRUE;
429    }
430    break;
431#ifdef ENTROPY_OPT_SUPPORTED
432  case huff_opt_pass:
433    /* Do Huffman optimization for a scan after the first one. */
434    select_scan_parameters(cinfo);
435    per_scan_setup(cinfo);
436    if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) {
437      (*cinfo->entropy->start_pass) (cinfo, TRUE);
438      (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
439      master->pub.call_pass_startup = FALSE;
440      break;
441    }
442    /* Special case: Huffman DC refinement scans need no Huffman table
443     * and therefore we can skip the optimization pass for them.
444     */
445    master->pass_type = output_pass;
446    master->pass_number++;
447    /*FALLTHROUGH*/
448#endif
449  case output_pass:
450    /* Do a data-output pass. */
451    /* We need not repeat per-scan setup if prior optimization pass did it. */
452    if (! cinfo->optimize_coding) {
453      select_scan_parameters(cinfo);
454      per_scan_setup(cinfo);
455    }
456    (*cinfo->entropy->start_pass) (cinfo, FALSE);
457    (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
458    /* We emit frame/scan headers now */
459    if (master->scan_number == 0)
460      (*cinfo->marker->write_frame_header) (cinfo);
461    (*cinfo->marker->write_scan_header) (cinfo);
462    master->pub.call_pass_startup = FALSE;
463    break;
464  default:
465    ERREXIT(cinfo, JERR_NOT_COMPILED);
466  }
467
468  master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
469
470  /* Set up progress monitor's pass info if present */
471  if (cinfo->progress != NULL) {
472    cinfo->progress->completed_passes = master->pass_number;
473    cinfo->progress->total_passes = master->total_passes;
474  }
475}
476
477
478/*
479 * Special start-of-pass hook.
480 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
481 * In single-pass processing, we need this hook because we don't want to
482 * write frame/scan headers during jpeg_start_compress; we want to let the
483 * application write COM markers etc. between jpeg_start_compress and the
484 * jpeg_write_scanlines loop.
485 * In multi-pass processing, this routine is not used.
486 */
487
488METHODDEF(void)
489pass_startup (j_compress_ptr cinfo)
490{
491  cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
492
493  (*cinfo->marker->write_frame_header) (cinfo);
494  (*cinfo->marker->write_scan_header) (cinfo);
495}
496
497
498/*
499 * Finish up at end of pass.
500 */
501
502METHODDEF(void)
503finish_pass_master (j_compress_ptr cinfo)
504{
505  my_master_ptr master = (my_master_ptr) cinfo->master;
506
507  /* The entropy coder always needs an end-of-pass call,
508   * either to analyze statistics or to flush its output buffer.
509   */
510  (*cinfo->entropy->finish_pass) (cinfo);
511
512  /* Update state for next pass */
513  switch (master->pass_type) {
514  case main_pass:
515    /* next pass is either output of scan 0 (after optimization)
516     * or output of scan 1 (if no optimization).
517     */
518    master->pass_type = output_pass;
519    if (! cinfo->optimize_coding)
520      master->scan_number++;
521    break;
522  case huff_opt_pass:
523    /* next pass is always output of current scan */
524    master->pass_type = output_pass;
525    break;
526  case output_pass:
527    /* next pass is either optimization or output of next scan */
528    if (cinfo->optimize_coding)
529      master->pass_type = huff_opt_pass;
530    master->scan_number++;
531    break;
532  }
533
534  master->pass_number++;
535}
536
537
538/*
539 * Initialize master compression control.
540 */
541
542GLOBAL(void)
543jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
544{
545  my_master_ptr master;
546
547  master = (my_master_ptr)
548      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
549                                  SIZEOF(my_comp_master));
550  cinfo->master = (struct jpeg_comp_master *) master;
551  master->pub.prepare_for_pass = prepare_for_pass;
552  master->pub.pass_startup = pass_startup;
553  master->pub.finish_pass = finish_pass_master;
554  master->pub.is_last_pass = FALSE;
555
556  /* Validate parameters, determine derived values */
557  initial_setup(cinfo);
558
559  if (cinfo->scan_info != NULL) {
560#ifdef C_MULTISCAN_FILES_SUPPORTED
561    validate_script(cinfo);
562#else
563    ERREXIT(cinfo, JERR_NOT_COMPILED);
564#endif
565  } else {
566    cinfo->progressive_mode = FALSE;
567    cinfo->num_scans = 1;
568  }
569
570  if (cinfo->progressive_mode)  /*  TEMPORARY HACK ??? */
571    cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
572
573  /* Initialize my private state */
574  if (transcode_only) {
575    /* no main pass in transcoding */
576    if (cinfo->optimize_coding)
577      master->pass_type = huff_opt_pass;
578    else
579      master->pass_type = output_pass;
580  } else {
581    /* for normal compression, first pass is always this type: */
582    master->pass_type = main_pass;
583  }
584  master->scan_number = 0;
585  master->pass_number = 0;
586  if (cinfo->optimize_coding)
587    master->total_passes = cinfo->num_scans * 2;
588  else
589    master->total_passes = cinfo->num_scans;
590}
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