source: trunk/libjpeg/jcmaster.c @ 283

Last change on this file since 283 was 283, checked in by rbri, 12 years ago

JPEG plugin: libjpeg updated to version 7

File size: 27.6 KB
Line 
1/*
2 * jcmaster.c
3 *
4 * Copyright (C) 1991-1997, Thomas G. Lane.
5 * Modified 2003-2009 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 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
22typedef 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
28typedef 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
39typedef my_comp_master * my_master_ptr;
40
41
42/*
43 * Support routines that do various essential calculations.
44 */
45
46/*
47 * Compute JPEG image dimensions and related values.
48 * NOTE: this is exported for possible use by application.
49 * Hence it mustn't do anything that can't be done twice.
50 */
51
52GLOBAL(void)
53jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
54/* Do computations that are needed before master selection phase */
55{
56#ifdef DCT_SCALING_SUPPORTED
57
58  /* Compute actual JPEG image dimensions and DCT scaling choices. */
59  if (cinfo->scale_num >= cinfo->scale_denom * 8) {
60    /* Provide 8/1 scaling */
61    cinfo->jpeg_width = cinfo->image_width << 3;
62    cinfo->jpeg_height = cinfo->image_height << 3;
63    cinfo->min_DCT_h_scaled_size = 1;
64    cinfo->min_DCT_v_scaled_size = 1;
65  } else if (cinfo->scale_num >= cinfo->scale_denom * 4) {
66    /* Provide 4/1 scaling */
67    cinfo->jpeg_width = cinfo->image_width << 2;
68    cinfo->jpeg_height = cinfo->image_height << 2;
69    cinfo->min_DCT_h_scaled_size = 2;
70    cinfo->min_DCT_v_scaled_size = 2;
71  } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 8) {
72    /* Provide 8/3 scaling */
73    cinfo->jpeg_width = (cinfo->image_width << 1) + (JDIMENSION)
74      jdiv_round_up((long) cinfo->image_width * 2, 3L);
75    cinfo->jpeg_height = (cinfo->image_height << 1) + (JDIMENSION)
76      jdiv_round_up((long) cinfo->image_height * 2, 3L);
77    cinfo->min_DCT_h_scaled_size = 3;
78    cinfo->min_DCT_v_scaled_size = 3;
79  } else if (cinfo->scale_num >= cinfo->scale_denom * 2) {
80    /* Provide 2/1 scaling */
81    cinfo->jpeg_width = cinfo->image_width << 1;
82    cinfo->jpeg_height = cinfo->image_height << 1;
83    cinfo->min_DCT_h_scaled_size = 4;
84    cinfo->min_DCT_v_scaled_size = 4;
85  } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 8) {
86    /* Provide 8/5 scaling */
87    cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
88      jdiv_round_up((long) cinfo->image_width * 3, 5L);
89    cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
90      jdiv_round_up((long) cinfo->image_height * 3, 5L);
91    cinfo->min_DCT_h_scaled_size = 5;
92    cinfo->min_DCT_v_scaled_size = 5;
93  } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 4) {
94    /* Provide 4/3 scaling */
95    cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
96      jdiv_round_up((long) cinfo->image_width, 3L);
97    cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
98      jdiv_round_up((long) cinfo->image_height, 3L);
99    cinfo->min_DCT_h_scaled_size = 6;
100    cinfo->min_DCT_v_scaled_size = 6;
101  } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 8) {
102    /* Provide 8/7 scaling */
103    cinfo->jpeg_width = cinfo->image_width + (JDIMENSION)
104      jdiv_round_up((long) cinfo->image_width, 7L);
105    cinfo->jpeg_height = cinfo->image_height + (JDIMENSION)
106      jdiv_round_up((long) cinfo->image_height, 7L);
107    cinfo->min_DCT_h_scaled_size = 7;
108    cinfo->min_DCT_v_scaled_size = 7;
109  } else if (cinfo->scale_num >= cinfo->scale_denom) {
110    /* Provide 1/1 scaling */
111    cinfo->jpeg_width = cinfo->image_width;
112    cinfo->jpeg_height = cinfo->image_height;
113    cinfo->min_DCT_h_scaled_size = DCTSIZE;
114    cinfo->min_DCT_v_scaled_size = DCTSIZE;
115  } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * 8) {
116    /* Provide 8/9 scaling */
117    cinfo->jpeg_width = (JDIMENSION)
118      jdiv_round_up((long) cinfo->image_width * 8, 9L);
119    cinfo->jpeg_height = (JDIMENSION)
120      jdiv_round_up((long) cinfo->image_height * 8, 9L);
121    cinfo->min_DCT_h_scaled_size = 9;
122    cinfo->min_DCT_v_scaled_size = 9;
123  } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 4) {
124    /* Provide 4/5 scaling */
125    cinfo->jpeg_width = (JDIMENSION)
126      jdiv_round_up((long) cinfo->image_width * 4, 5L);
127    cinfo->jpeg_height = (JDIMENSION)
128      jdiv_round_up((long) cinfo->image_height * 4, 5L);
129    cinfo->min_DCT_h_scaled_size = 10;
130    cinfo->min_DCT_v_scaled_size = 10;
131  } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * 8) {
132    /* Provide 8/11 scaling */
133    cinfo->jpeg_width = (JDIMENSION)
134      jdiv_round_up((long) cinfo->image_width * 8, 11L);
135    cinfo->jpeg_height = (JDIMENSION)
136      jdiv_round_up((long) cinfo->image_height * 8, 11L);
137    cinfo->min_DCT_h_scaled_size = 11;
138    cinfo->min_DCT_v_scaled_size = 11;
139  } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 2) {
140    /* Provide 2/3 scaling */
141    cinfo->jpeg_width = (JDIMENSION)
142      jdiv_round_up((long) cinfo->image_width * 2, 3L);
143    cinfo->jpeg_height = (JDIMENSION)
144      jdiv_round_up((long) cinfo->image_height * 2, 3L);
145    cinfo->min_DCT_h_scaled_size = 12;
146    cinfo->min_DCT_v_scaled_size = 12;
147  } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * 8) {
148    /* Provide 8/13 scaling */
149    cinfo->jpeg_width = (JDIMENSION)
150      jdiv_round_up((long) cinfo->image_width * 8, 13L);
151    cinfo->jpeg_height = (JDIMENSION)
152      jdiv_round_up((long) cinfo->image_height * 8, 13L);
153    cinfo->min_DCT_h_scaled_size = 13;
154    cinfo->min_DCT_v_scaled_size = 13;
155  } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 4) {
156    /* Provide 4/7 scaling */
157    cinfo->jpeg_width = (JDIMENSION)
158      jdiv_round_up((long) cinfo->image_width * 4, 7L);
159    cinfo->jpeg_height = (JDIMENSION)
160      jdiv_round_up((long) cinfo->image_height * 4, 7L);
161    cinfo->min_DCT_h_scaled_size = 14;
162    cinfo->min_DCT_v_scaled_size = 14;
163  } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * 8) {
164    /* Provide 8/15 scaling */
165    cinfo->jpeg_width = (JDIMENSION)
166      jdiv_round_up((long) cinfo->image_width * 8, 15L);
167    cinfo->jpeg_height = (JDIMENSION)
168      jdiv_round_up((long) cinfo->image_height * 8, 15L);
169    cinfo->min_DCT_h_scaled_size = 15;
170    cinfo->min_DCT_v_scaled_size = 15;
171  } else {
172    /* Provide 1/2 scaling */
173    cinfo->jpeg_width = (JDIMENSION)
174      jdiv_round_up((long) cinfo->image_width, 2L);
175    cinfo->jpeg_height = (JDIMENSION)
176      jdiv_round_up((long) cinfo->image_height, 2L);
177    cinfo->min_DCT_h_scaled_size = 16;
178    cinfo->min_DCT_v_scaled_size = 16;
179  }
180
181#else /* !DCT_SCALING_SUPPORTED */
182
183  /* Hardwire it to "no scaling" */
184  cinfo->jpeg_width = cinfo->image_width;
185  cinfo->jpeg_height = cinfo->image_height;
186  cinfo->min_DCT_h_scaled_size = DCTSIZE;
187  cinfo->min_DCT_v_scaled_size = DCTSIZE;
188
189#endif /* DCT_SCALING_SUPPORTED */
190}
191
192
193LOCAL(void)
194initial_setup (j_compress_ptr cinfo)
195/* Do computations that are needed before master selection phase */
196{
197  int ci, ssize;
198  jpeg_component_info *compptr;
199  long samplesperrow;
200  JDIMENSION jd_samplesperrow;
201
202  jpeg_calc_jpeg_dimensions(cinfo);
203
204  /* Sanity check on image dimensions */
205  if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0
206      || cinfo->num_components <= 0 || cinfo->input_components <= 0)
207    ERREXIT(cinfo, JERR_EMPTY_IMAGE);
208
209  /* Make sure image isn't bigger than I can handle */
210  if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION ||
211      (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION)
212    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
213
214  /* Width of an input scanline must be representable as JDIMENSION. */
215  samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
216  jd_samplesperrow = (JDIMENSION) samplesperrow;
217  if ((long) jd_samplesperrow != samplesperrow)
218    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
219
220  /* For now, precision must match compiled-in value... */
221  if (cinfo->data_precision != BITS_IN_JSAMPLE)
222    ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
223
224  /* Check that number of components won't exceed internal array sizes */
225  if (cinfo->num_components > MAX_COMPONENTS)
226    ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
227             MAX_COMPONENTS);
228
229  /* Compute maximum sampling factors; check factor validity */
230  cinfo->max_h_samp_factor = 1;
231  cinfo->max_v_samp_factor = 1;
232  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
233       ci++, compptr++) {
234    if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
235        compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
236      ERREXIT(cinfo, JERR_BAD_SAMPLING);
237    cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
238                                   compptr->h_samp_factor);
239    cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
240                                   compptr->v_samp_factor);
241  }
242
243  /* Compute dimensions of components */
244  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
245       ci++, compptr++) {
246    /* Fill in the correct component_index value; don't rely on application */
247    compptr->component_index = ci;
248    /* In selecting the actual DCT scaling for each component, we try to
249     * scale down the chroma components via DCT scaling rather than downsampling.
250     * This saves time if the downsampler gets to use 1:1 scaling.
251     * Note this code adapts subsampling ratios which are powers of 2.
252     */
253    ssize = 1;
254#ifdef DCT_SCALING_SUPPORTED
255    while (cinfo->min_DCT_h_scaled_size * ssize <=
256           (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
257           (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) {
258      ssize = ssize * 2;
259    }
260#endif
261    compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize;
262    ssize = 1;
263#ifdef DCT_SCALING_SUPPORTED
264    while (cinfo->min_DCT_v_scaled_size * ssize <=
265           (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) &&
266           (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) {
267      ssize = ssize * 2;
268    }
269#endif
270    compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize;
271
272    /* We don't support DCT ratios larger than 2. */
273    if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2)
274        compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2;
275    else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2)
276        compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2;
277
278    /* Size in DCT blocks */
279    compptr->width_in_blocks = (JDIMENSION)
280      jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
281                    (long) (cinfo->max_h_samp_factor * DCTSIZE));
282    compptr->height_in_blocks = (JDIMENSION)
283      jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
284                    (long) (cinfo->max_v_samp_factor * DCTSIZE));
285    /* Size in samples */
286    compptr->downsampled_width = (JDIMENSION)
287      jdiv_round_up((long) cinfo->jpeg_width *
288                    (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
289                    (long) (cinfo->max_h_samp_factor * DCTSIZE));
290    compptr->downsampled_height = (JDIMENSION)
291      jdiv_round_up((long) cinfo->jpeg_height *
292                    (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
293                    (long) (cinfo->max_v_samp_factor * DCTSIZE));
294    /* Mark component needed (this flag isn't actually used for compression) */
295    compptr->component_needed = TRUE;
296  }
297
298  /* Compute number of fully interleaved MCU rows (number of times that
299   * main controller will call coefficient controller).
300   */
301  cinfo->total_iMCU_rows = (JDIMENSION)
302    jdiv_round_up((long) cinfo->jpeg_height,
303                  (long) (cinfo->max_v_samp_factor*DCTSIZE));
304}
305
306
307#ifdef C_MULTISCAN_FILES_SUPPORTED
308
309LOCAL(void)
310validate_script (j_compress_ptr cinfo)
311/* Verify that the scan script in cinfo->scan_info[] is valid; also
312 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
313 */
314{
315  const jpeg_scan_info * scanptr;
316  int scanno, ncomps, ci, coefi, thisi;
317  int Ss, Se, Ah, Al;
318  boolean component_sent[MAX_COMPONENTS];
319#ifdef C_PROGRESSIVE_SUPPORTED
320  int * last_bitpos_ptr;
321  int last_bitpos[MAX_COMPONENTS][DCTSIZE2];
322  /* -1 until that coefficient has been seen; then last Al for it */
323#endif
324
325  if (cinfo->num_scans <= 0)
326    ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);
327
328  /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
329   * for progressive JPEG, no scan can have this.
330   */
331  scanptr = cinfo->scan_info;
332  if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) {
333#ifdef C_PROGRESSIVE_SUPPORTED
334    cinfo->progressive_mode = TRUE;
335    last_bitpos_ptr = & last_bitpos[0][0];
336    for (ci = 0; ci < cinfo->num_components; ci++) 
337      for (coefi = 0; coefi < DCTSIZE2; coefi++)
338        *last_bitpos_ptr++ = -1;
339#else
340    ERREXIT(cinfo, JERR_NOT_COMPILED);
341#endif
342  } else {
343    cinfo->progressive_mode = FALSE;
344    for (ci = 0; ci < cinfo->num_components; ci++) 
345      component_sent[ci] = FALSE;
346  }
347
348  for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) {
349    /* Validate component indexes */
350    ncomps = scanptr->comps_in_scan;
351    if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
352      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
353    for (ci = 0; ci < ncomps; ci++) {
354      thisi = scanptr->component_index[ci];
355      if (thisi < 0 || thisi >= cinfo->num_components)
356        ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
357      /* Components must appear in SOF order within each scan */
358      if (ci > 0 && thisi <= scanptr->component_index[ci-1])
359        ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
360    }
361    /* Validate progression parameters */
362    Ss = scanptr->Ss;
363    Se = scanptr->Se;
364    Ah = scanptr->Ah;
365    Al = scanptr->Al;
366    if (cinfo->progressive_mode) {
367#ifdef C_PROGRESSIVE_SUPPORTED
368      /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that
369       * seems wrong: the upper bound ought to depend on data precision.
370       * Perhaps they really meant 0..N+1 for N-bit precision.
371       * Here we allow 0..10 for 8-bit data; Al larger than 10 results in
372       * out-of-range reconstructed DC values during the first DC scan,
373       * which might cause problems for some decoders.
374       */
375#if BITS_IN_JSAMPLE == 8
376#define MAX_AH_AL 10
377#else
378#define MAX_AH_AL 13
379#endif
380      if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 ||
381          Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL)
382        ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
383      if (Ss == 0) {
384        if (Se != 0)            /* DC and AC together not OK */
385          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
386      } else {
387        if (ncomps != 1)        /* AC scans must be for only one component */
388          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
389      }
390      for (ci = 0; ci < ncomps; ci++) {
391        last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0];
392        if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */
393          ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
394        for (coefi = Ss; coefi <= Se; coefi++) {
395          if (last_bitpos_ptr[coefi] < 0) {
396            /* first scan of this coefficient */
397            if (Ah != 0)
398              ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
399          } else {
400            /* not first scan */
401            if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1)
402              ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
403          }
404          last_bitpos_ptr[coefi] = Al;
405        }
406      }
407#endif
408    } else {
409      /* For sequential JPEG, all progression parameters must be these: */
410      if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0)
411        ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
412      /* Make sure components are not sent twice */
413      for (ci = 0; ci < ncomps; ci++) {
414        thisi = scanptr->component_index[ci];
415        if (component_sent[thisi])
416          ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
417        component_sent[thisi] = TRUE;
418      }
419    }
420  }
421
422  /* Now verify that everything got sent. */
423  if (cinfo->progressive_mode) {
424#ifdef C_PROGRESSIVE_SUPPORTED
425    /* For progressive mode, we only check that at least some DC data
426     * got sent for each component; the spec does not require that all bits
427     * of all coefficients be transmitted.  Would it be wiser to enforce
428     * transmission of all coefficient bits??
429     */
430    for (ci = 0; ci < cinfo->num_components; ci++) {
431      if (last_bitpos[ci][0] < 0)
432        ERREXIT(cinfo, JERR_MISSING_DATA);
433    }
434#endif
435  } else {
436    for (ci = 0; ci < cinfo->num_components; ci++) {
437      if (! component_sent[ci])
438        ERREXIT(cinfo, JERR_MISSING_DATA);
439    }
440  }
441}
442
443#endif /* C_MULTISCAN_FILES_SUPPORTED */
444
445
446LOCAL(void)
447select_scan_parameters (j_compress_ptr cinfo)
448/* Set up the scan parameters for the current scan */
449{
450  int ci;
451
452#ifdef C_MULTISCAN_FILES_SUPPORTED
453  if (cinfo->scan_info != NULL) {
454    /* Prepare for current scan --- the script is already validated */
455    my_master_ptr master = (my_master_ptr) cinfo->master;
456    const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number;
457
458    cinfo->comps_in_scan = scanptr->comps_in_scan;
459    for (ci = 0; ci < scanptr->comps_in_scan; ci++) {
460      cinfo->cur_comp_info[ci] =
461        &cinfo->comp_info[scanptr->component_index[ci]];
462    }
463    cinfo->Ss = scanptr->Ss;
464    cinfo->Se = scanptr->Se;
465    cinfo->Ah = scanptr->Ah;
466    cinfo->Al = scanptr->Al;
467  }
468  else
469#endif
470  {
471    /* Prepare for single sequential-JPEG scan containing all components */
472    if (cinfo->num_components > MAX_COMPS_IN_SCAN)
473      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
474               MAX_COMPS_IN_SCAN);
475    cinfo->comps_in_scan = cinfo->num_components;
476    for (ci = 0; ci < cinfo->num_components; ci++) {
477      cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
478    }
479    cinfo->Ss = 0;
480    cinfo->Se = DCTSIZE2-1;
481    cinfo->Ah = 0;
482    cinfo->Al = 0;
483  }
484}
485
486
487LOCAL(void)
488per_scan_setup (j_compress_ptr cinfo)
489/* Do computations that are needed before processing a JPEG scan */
490/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
491{
492  int ci, mcublks, tmp;
493  jpeg_component_info *compptr;
494 
495  if (cinfo->comps_in_scan == 1) {
496   
497    /* Noninterleaved (single-component) scan */
498    compptr = cinfo->cur_comp_info[0];
499   
500    /* Overall image size in MCUs */
501    cinfo->MCUs_per_row = compptr->width_in_blocks;
502    cinfo->MCU_rows_in_scan = compptr->height_in_blocks;
503   
504    /* For noninterleaved scan, always one block per MCU */
505    compptr->MCU_width = 1;
506    compptr->MCU_height = 1;
507    compptr->MCU_blocks = 1;
508    compptr->MCU_sample_width = compptr->DCT_h_scaled_size;
509    compptr->last_col_width = 1;
510    /* For noninterleaved scans, it is convenient to define last_row_height
511     * as the number of block rows present in the last iMCU row.
512     */
513    tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
514    if (tmp == 0) tmp = compptr->v_samp_factor;
515    compptr->last_row_height = tmp;
516   
517    /* Prepare array describing MCU composition */
518    cinfo->blocks_in_MCU = 1;
519    cinfo->MCU_membership[0] = 0;
520   
521  } else {
522   
523    /* Interleaved (multi-component) scan */
524    if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
525      ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
526               MAX_COMPS_IN_SCAN);
527   
528    /* Overall image size in MCUs */
529    cinfo->MCUs_per_row = (JDIMENSION)
530      jdiv_round_up((long) cinfo->jpeg_width,
531                    (long) (cinfo->max_h_samp_factor*DCTSIZE));
532    cinfo->MCU_rows_in_scan = (JDIMENSION)
533      jdiv_round_up((long) cinfo->jpeg_height,
534                    (long) (cinfo->max_v_samp_factor*DCTSIZE));
535   
536    cinfo->blocks_in_MCU = 0;
537   
538    for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
539      compptr = cinfo->cur_comp_info[ci];
540      /* Sampling factors give # of blocks of component in each MCU */
541      compptr->MCU_width = compptr->h_samp_factor;
542      compptr->MCU_height = compptr->v_samp_factor;
543      compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
544      compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size;
545      /* Figure number of non-dummy blocks in last MCU column & row */
546      tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
547      if (tmp == 0) tmp = compptr->MCU_width;
548      compptr->last_col_width = tmp;
549      tmp = (int) (compptr->height_in_blocks % compptr->MCU_height);
550      if (tmp == 0) tmp = compptr->MCU_height;
551      compptr->last_row_height = tmp;
552      /* Prepare array describing MCU composition */
553      mcublks = compptr->MCU_blocks;
554      if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
555        ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
556      while (mcublks-- > 0) {
557        cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
558      }
559    }
560   
561  }
562
563  /* Convert restart specified in rows to actual MCU count. */
564  /* Note that count must fit in 16 bits, so we provide limiting. */
565  if (cinfo->restart_in_rows > 0) {
566    long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row;
567    cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L);
568  }
569}
570
571
572/*
573 * Per-pass setup.
574 * This is called at the beginning of each pass.  We determine which modules
575 * will be active during this pass and give them appropriate start_pass calls.
576 * We also set is_last_pass to indicate whether any more passes will be
577 * required.
578 */
579
580METHODDEF(void)
581prepare_for_pass (j_compress_ptr cinfo)
582{
583  my_master_ptr master = (my_master_ptr) cinfo->master;
584
585  switch (master->pass_type) {
586  case main_pass:
587    /* Initial pass: will collect input data, and do either Huffman
588     * optimization or data output for the first scan.
589     */
590    select_scan_parameters(cinfo);
591    per_scan_setup(cinfo);
592    if (! cinfo->raw_data_in) {
593      (*cinfo->cconvert->start_pass) (cinfo);
594      (*cinfo->downsample->start_pass) (cinfo);
595      (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
596    }
597    (*cinfo->fdct->start_pass) (cinfo);
598    (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
599    (*cinfo->coef->start_pass) (cinfo,
600                                (master->total_passes > 1 ?
601                                 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
602    (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
603    if (cinfo->optimize_coding) {
604      /* No immediate data output; postpone writing frame/scan headers */
605      master->pub.call_pass_startup = FALSE;
606    } else {
607      /* Will write frame/scan headers at first jpeg_write_scanlines call */
608      master->pub.call_pass_startup = TRUE;
609    }
610    break;
611#ifdef ENTROPY_OPT_SUPPORTED
612  case huff_opt_pass:
613    /* Do Huffman optimization for a scan after the first one. */
614    select_scan_parameters(cinfo);
615    per_scan_setup(cinfo);
616    if (cinfo->Ss != 0 || cinfo->Ah == 0) {
617      (*cinfo->entropy->start_pass) (cinfo, TRUE);
618      (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
619      master->pub.call_pass_startup = FALSE;
620      break;
621    }
622    /* Special case: Huffman DC refinement scans need no Huffman table
623     * and therefore we can skip the optimization pass for them.
624     */
625    master->pass_type = output_pass;
626    master->pass_number++;
627    /*FALLTHROUGH*/
628#endif
629  case output_pass:
630    /* Do a data-output pass. */
631    /* We need not repeat per-scan setup if prior optimization pass did it. */
632    if (! cinfo->optimize_coding) {
633      select_scan_parameters(cinfo);
634      per_scan_setup(cinfo);
635    }
636    (*cinfo->entropy->start_pass) (cinfo, FALSE);
637    (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
638    /* We emit frame/scan headers now */
639    if (master->scan_number == 0)
640      (*cinfo->marker->write_frame_header) (cinfo);
641    (*cinfo->marker->write_scan_header) (cinfo);
642    master->pub.call_pass_startup = FALSE;
643    break;
644  default:
645    ERREXIT(cinfo, JERR_NOT_COMPILED);
646  }
647
648  master->pub.is_last_pass = (master->pass_number == master->total_passes-1);
649
650  /* Set up progress monitor's pass info if present */
651  if (cinfo->progress != NULL) {
652    cinfo->progress->completed_passes = master->pass_number;
653    cinfo->progress->total_passes = master->total_passes;
654  }
655}
656
657
658/*
659 * Special start-of-pass hook.
660 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
661 * In single-pass processing, we need this hook because we don't want to
662 * write frame/scan headers during jpeg_start_compress; we want to let the
663 * application write COM markers etc. between jpeg_start_compress and the
664 * jpeg_write_scanlines loop.
665 * In multi-pass processing, this routine is not used.
666 */
667
668METHODDEF(void)
669pass_startup (j_compress_ptr cinfo)
670{
671  cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */
672
673  (*cinfo->marker->write_frame_header) (cinfo);
674  (*cinfo->marker->write_scan_header) (cinfo);
675}
676
677
678/*
679 * Finish up at end of pass.
680 */
681
682METHODDEF(void)
683finish_pass_master (j_compress_ptr cinfo)
684{
685  my_master_ptr master = (my_master_ptr) cinfo->master;
686
687  /* The entropy coder always needs an end-of-pass call,
688   * either to analyze statistics or to flush its output buffer.
689   */
690  (*cinfo->entropy->finish_pass) (cinfo);
691
692  /* Update state for next pass */
693  switch (master->pass_type) {
694  case main_pass:
695    /* next pass is either output of scan 0 (after optimization)
696     * or output of scan 1 (if no optimization).
697     */
698    master->pass_type = output_pass;
699    if (! cinfo->optimize_coding)
700      master->scan_number++;
701    break;
702  case huff_opt_pass:
703    /* next pass is always output of current scan */
704    master->pass_type = output_pass;
705    break;
706  case output_pass:
707    /* next pass is either optimization or output of next scan */
708    if (cinfo->optimize_coding)
709      master->pass_type = huff_opt_pass;
710    master->scan_number++;
711    break;
712  }
713
714  master->pass_number++;
715}
716
717
718/*
719 * Initialize master compression control.
720 */
721
722GLOBAL(void)
723jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
724{
725  my_master_ptr master;
726
727  master = (my_master_ptr)
728      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
729                                  SIZEOF(my_comp_master));
730  cinfo->master = (struct jpeg_comp_master *) master;
731  master->pub.prepare_for_pass = prepare_for_pass;
732  master->pub.pass_startup = pass_startup;
733  master->pub.finish_pass = finish_pass_master;
734  master->pub.is_last_pass = FALSE;
735
736  /* Validate parameters, determine derived values */
737  initial_setup(cinfo);
738
739  if (cinfo->scan_info != NULL) {
740#ifdef C_MULTISCAN_FILES_SUPPORTED
741    validate_script(cinfo);
742#else
743    ERREXIT(cinfo, JERR_NOT_COMPILED);
744#endif
745  } else {
746    cinfo->progressive_mode = FALSE;
747    cinfo->num_scans = 1;
748  }
749
750  if (cinfo->progressive_mode && cinfo->arith_code == 0)        /*  TEMPORARY HACK ??? */
751    cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
752
753  /* Initialize my private state */
754  if (transcode_only) {
755    /* no main pass in transcoding */
756    if (cinfo->optimize_coding)
757      master->pass_type = huff_opt_pass;
758    else
759      master->pass_type = output_pass;
760  } else {
761    /* for normal compression, first pass is always this type: */
762    master->pass_type = main_pass;
763  }
764  master->scan_number = 0;
765  master->pass_number = 0;
766  if (cinfo->optimize_coding)
767    master->total_passes = cinfo->num_scans * 2;
768  else
769    master->total_passes = cinfo->num_scans;
770}
Note: See TracBrowser for help on using the repository browser.