media/libjpeg/jdmaster.c@b8a032363ba2
media/libjpeg/jdmaster.c
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
1 /*
2 * jdmaster.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * Modified 2002-2009 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2009-2011, D. R. Commander.
9 * For conditions of distribution and use, see the accompanying README file.
10 *
11 * This file contains master control logic for the JPEG decompressor.
12 * These routines are concerned with selecting the modules to be executed
13 * and with determining the number of passes and the work to be done in each
14 * pass.
15 */
17 #define JPEG_INTERNALS
18 #include "jinclude.h"
19 #include "jpeglib.h"
20 #include "jpegcomp.h"
23 /* Private state */
25 typedef struct {
26 struct jpeg_decomp_master pub; /* public fields */
28 int pass_number; /* # of passes completed */
30 boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */
32 /* Saved references to initialized quantizer modules,
33 * in case we need to switch modes.
34 */
35 struct jpeg_color_quantizer * quantizer_1pass;
36 struct jpeg_color_quantizer * quantizer_2pass;
37 } my_decomp_master;
39 typedef my_decomp_master * my_master_ptr;
42 /*
43 * Determine whether merged upsample/color conversion should be used.
44 * CRUCIAL: this must match the actual capabilities of jdmerge.c!
45 */
47 LOCAL(boolean)
48 use_merged_upsample (j_decompress_ptr cinfo)
49 {
50 #ifdef UPSAMPLE_MERGING_SUPPORTED
51 /* Merging is the equivalent of plain box-filter upsampling */
52 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
53 return FALSE;
54 /* jdmerge.c only supports YCC=>RGB color conversion */
55 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
56 (cinfo->out_color_space != JCS_RGB &&
57 cinfo->out_color_space != JCS_EXT_RGB &&
58 cinfo->out_color_space != JCS_EXT_RGBX &&
59 cinfo->out_color_space != JCS_EXT_BGR &&
60 cinfo->out_color_space != JCS_EXT_BGRX &&
61 cinfo->out_color_space != JCS_EXT_XBGR &&
62 cinfo->out_color_space != JCS_EXT_XRGB &&
63 cinfo->out_color_space != JCS_EXT_RGBA &&
64 cinfo->out_color_space != JCS_EXT_BGRA &&
65 cinfo->out_color_space != JCS_EXT_ABGR &&
66 cinfo->out_color_space != JCS_EXT_ARGB) ||
67 cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space])
68 return FALSE;
69 /* and it only handles 2h1v or 2h2v sampling ratios */
70 if (cinfo->comp_info[0].h_samp_factor != 2 ||
71 cinfo->comp_info[1].h_samp_factor != 1 ||
72 cinfo->comp_info[2].h_samp_factor != 1 ||
73 cinfo->comp_info[0].v_samp_factor > 2 ||
74 cinfo->comp_info[1].v_samp_factor != 1 ||
75 cinfo->comp_info[2].v_samp_factor != 1)
76 return FALSE;
77 /* furthermore, it doesn't work if we've scaled the IDCTs differently */
78 if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
79 cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
80 cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size)
81 return FALSE;
82 /* ??? also need to test for upsample-time rescaling, when & if supported */
83 return TRUE; /* by golly, it'll work... */
84 #else
85 return FALSE;
86 #endif
87 }
90 /*
91 * Compute output image dimensions and related values.
92 * NOTE: this is exported for possible use by application.
93 * Hence it mustn't do anything that can't be done twice.
94 */
96 #if JPEG_LIB_VERSION >= 80
97 GLOBAL(void)
98 #else
99 LOCAL(void)
100 #endif
101 jpeg_core_output_dimensions (j_decompress_ptr cinfo)
102 /* Do computations that are needed before master selection phase.
103 * This function is used for transcoding and full decompression.
104 */
105 {
106 #ifdef IDCT_SCALING_SUPPORTED
107 int ci;
108 jpeg_component_info *compptr;
110 /* Compute actual output image dimensions and DCT scaling choices. */
111 if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) {
112 /* Provide 1/block_size scaling */
113 cinfo->output_width = (JDIMENSION)
114 jdiv_round_up((long) cinfo->image_width, (long) DCTSIZE);
115 cinfo->output_height = (JDIMENSION)
116 jdiv_round_up((long) cinfo->image_height, (long) DCTSIZE);
117 cinfo->_min_DCT_h_scaled_size = 1;
118 cinfo->_min_DCT_v_scaled_size = 1;
119 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) {
120 /* Provide 2/block_size scaling */
121 cinfo->output_width = (JDIMENSION)
122 jdiv_round_up((long) cinfo->image_width * 2L, (long) DCTSIZE);
123 cinfo->output_height = (JDIMENSION)
124 jdiv_round_up((long) cinfo->image_height * 2L, (long) DCTSIZE);
125 cinfo->_min_DCT_h_scaled_size = 2;
126 cinfo->_min_DCT_v_scaled_size = 2;
127 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) {
128 /* Provide 3/block_size scaling */
129 cinfo->output_width = (JDIMENSION)
130 jdiv_round_up((long) cinfo->image_width * 3L, (long) DCTSIZE);
131 cinfo->output_height = (JDIMENSION)
132 jdiv_round_up((long) cinfo->image_height * 3L, (long) DCTSIZE);
133 cinfo->_min_DCT_h_scaled_size = 3;
134 cinfo->_min_DCT_v_scaled_size = 3;
135 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) {
136 /* Provide 4/block_size scaling */
137 cinfo->output_width = (JDIMENSION)
138 jdiv_round_up((long) cinfo->image_width * 4L, (long) DCTSIZE);
139 cinfo->output_height = (JDIMENSION)
140 jdiv_round_up((long) cinfo->image_height * 4L, (long) DCTSIZE);
141 cinfo->_min_DCT_h_scaled_size = 4;
142 cinfo->_min_DCT_v_scaled_size = 4;
143 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) {
144 /* Provide 5/block_size scaling */
145 cinfo->output_width = (JDIMENSION)
146 jdiv_round_up((long) cinfo->image_width * 5L, (long) DCTSIZE);
147 cinfo->output_height = (JDIMENSION)
148 jdiv_round_up((long) cinfo->image_height * 5L, (long) DCTSIZE);
149 cinfo->_min_DCT_h_scaled_size = 5;
150 cinfo->_min_DCT_v_scaled_size = 5;
151 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) {
152 /* Provide 6/block_size scaling */
153 cinfo->output_width = (JDIMENSION)
154 jdiv_round_up((long) cinfo->image_width * 6L, (long) DCTSIZE);
155 cinfo->output_height = (JDIMENSION)
156 jdiv_round_up((long) cinfo->image_height * 6L, (long) DCTSIZE);
157 cinfo->_min_DCT_h_scaled_size = 6;
158 cinfo->_min_DCT_v_scaled_size = 6;
159 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) {
160 /* Provide 7/block_size scaling */
161 cinfo->output_width = (JDIMENSION)
162 jdiv_round_up((long) cinfo->image_width * 7L, (long) DCTSIZE);
163 cinfo->output_height = (JDIMENSION)
164 jdiv_round_up((long) cinfo->image_height * 7L, (long) DCTSIZE);
165 cinfo->_min_DCT_h_scaled_size = 7;
166 cinfo->_min_DCT_v_scaled_size = 7;
167 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) {
168 /* Provide 8/block_size scaling */
169 cinfo->output_width = (JDIMENSION)
170 jdiv_round_up((long) cinfo->image_width * 8L, (long) DCTSIZE);
171 cinfo->output_height = (JDIMENSION)
172 jdiv_round_up((long) cinfo->image_height * 8L, (long) DCTSIZE);
173 cinfo->_min_DCT_h_scaled_size = 8;
174 cinfo->_min_DCT_v_scaled_size = 8;
175 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) {
176 /* Provide 9/block_size scaling */
177 cinfo->output_width = (JDIMENSION)
178 jdiv_round_up((long) cinfo->image_width * 9L, (long) DCTSIZE);
179 cinfo->output_height = (JDIMENSION)
180 jdiv_round_up((long) cinfo->image_height * 9L, (long) DCTSIZE);
181 cinfo->_min_DCT_h_scaled_size = 9;
182 cinfo->_min_DCT_v_scaled_size = 9;
183 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) {
184 /* Provide 10/block_size scaling */
185 cinfo->output_width = (JDIMENSION)
186 jdiv_round_up((long) cinfo->image_width * 10L, (long) DCTSIZE);
187 cinfo->output_height = (JDIMENSION)
188 jdiv_round_up((long) cinfo->image_height * 10L, (long) DCTSIZE);
189 cinfo->_min_DCT_h_scaled_size = 10;
190 cinfo->_min_DCT_v_scaled_size = 10;
191 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) {
192 /* Provide 11/block_size scaling */
193 cinfo->output_width = (JDIMENSION)
194 jdiv_round_up((long) cinfo->image_width * 11L, (long) DCTSIZE);
195 cinfo->output_height = (JDIMENSION)
196 jdiv_round_up((long) cinfo->image_height * 11L, (long) DCTSIZE);
197 cinfo->_min_DCT_h_scaled_size = 11;
198 cinfo->_min_DCT_v_scaled_size = 11;
199 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) {
200 /* Provide 12/block_size scaling */
201 cinfo->output_width = (JDIMENSION)
202 jdiv_round_up((long) cinfo->image_width * 12L, (long) DCTSIZE);
203 cinfo->output_height = (JDIMENSION)
204 jdiv_round_up((long) cinfo->image_height * 12L, (long) DCTSIZE);
205 cinfo->_min_DCT_h_scaled_size = 12;
206 cinfo->_min_DCT_v_scaled_size = 12;
207 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) {
208 /* Provide 13/block_size scaling */
209 cinfo->output_width = (JDIMENSION)
210 jdiv_round_up((long) cinfo->image_width * 13L, (long) DCTSIZE);
211 cinfo->output_height = (JDIMENSION)
212 jdiv_round_up((long) cinfo->image_height * 13L, (long) DCTSIZE);
213 cinfo->_min_DCT_h_scaled_size = 13;
214 cinfo->_min_DCT_v_scaled_size = 13;
215 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) {
216 /* Provide 14/block_size scaling */
217 cinfo->output_width = (JDIMENSION)
218 jdiv_round_up((long) cinfo->image_width * 14L, (long) DCTSIZE);
219 cinfo->output_height = (JDIMENSION)
220 jdiv_round_up((long) cinfo->image_height * 14L, (long) DCTSIZE);
221 cinfo->_min_DCT_h_scaled_size = 14;
222 cinfo->_min_DCT_v_scaled_size = 14;
223 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) {
224 /* Provide 15/block_size scaling */
225 cinfo->output_width = (JDIMENSION)
226 jdiv_round_up((long) cinfo->image_width * 15L, (long) DCTSIZE);
227 cinfo->output_height = (JDIMENSION)
228 jdiv_round_up((long) cinfo->image_height * 15L, (long) DCTSIZE);
229 cinfo->_min_DCT_h_scaled_size = 15;
230 cinfo->_min_DCT_v_scaled_size = 15;
231 } else {
232 /* Provide 16/block_size scaling */
233 cinfo->output_width = (JDIMENSION)
234 jdiv_round_up((long) cinfo->image_width * 16L, (long) DCTSIZE);
235 cinfo->output_height = (JDIMENSION)
236 jdiv_round_up((long) cinfo->image_height * 16L, (long) DCTSIZE);
237 cinfo->_min_DCT_h_scaled_size = 16;
238 cinfo->_min_DCT_v_scaled_size = 16;
239 }
241 /* Recompute dimensions of components */
242 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
243 ci++, compptr++) {
244 compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size;
245 compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size;
246 }
248 #else /* !IDCT_SCALING_SUPPORTED */
250 /* Hardwire it to "no scaling" */
251 cinfo->output_width = cinfo->image_width;
252 cinfo->output_height = cinfo->image_height;
253 /* jdinput.c has already initialized DCT_scaled_size,
254 * and has computed unscaled downsampled_width and downsampled_height.
255 */
257 #endif /* IDCT_SCALING_SUPPORTED */
258 }
261 /*
262 * Compute output image dimensions and related values.
263 * NOTE: this is exported for possible use by application.
264 * Hence it mustn't do anything that can't be done twice.
265 * Also note that it may be called before the master module is initialized!
266 */
268 GLOBAL(void)
269 jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
270 /* Do computations that are needed before master selection phase */
271 {
272 #ifdef IDCT_SCALING_SUPPORTED
273 int ci;
274 jpeg_component_info *compptr;
275 #endif
277 /* Prevent application from calling me at wrong times */
278 if (cinfo->global_state != DSTATE_READY)
279 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
281 /* Compute core output image dimensions and DCT scaling choices. */
282 jpeg_core_output_dimensions(cinfo);
284 #ifdef IDCT_SCALING_SUPPORTED
286 /* In selecting the actual DCT scaling for each component, we try to
287 * scale up the chroma components via IDCT scaling rather than upsampling.
288 * This saves time if the upsampler gets to use 1:1 scaling.
289 * Note this code adapts subsampling ratios which are powers of 2.
290 */
291 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
292 ci++, compptr++) {
293 int ssize = cinfo->_min_DCT_scaled_size;
294 while (ssize < DCTSIZE &&
295 ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) %
296 (compptr->h_samp_factor * ssize * 2) == 0) &&
297 ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) %
298 (compptr->v_samp_factor * ssize * 2) == 0)) {
299 ssize = ssize * 2;
300 }
301 #if JPEG_LIB_VERSION >= 70
302 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize;
303 #else
304 compptr->DCT_scaled_size = ssize;
305 #endif
306 }
308 /* Recompute downsampled dimensions of components;
309 * application needs to know these if using raw downsampled data.
310 */
311 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
312 ci++, compptr++) {
313 /* Size in samples, after IDCT scaling */
314 compptr->downsampled_width = (JDIMENSION)
315 jdiv_round_up((long) cinfo->image_width *
316 (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size),
317 (long) (cinfo->max_h_samp_factor * DCTSIZE));
318 compptr->downsampled_height = (JDIMENSION)
319 jdiv_round_up((long) cinfo->image_height *
320 (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size),
321 (long) (cinfo->max_v_samp_factor * DCTSIZE));
322 }
324 #else /* !IDCT_SCALING_SUPPORTED */
326 /* Hardwire it to "no scaling" */
327 cinfo->output_width = cinfo->image_width;
328 cinfo->output_height = cinfo->image_height;
329 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
330 * and has computed unscaled downsampled_width and downsampled_height.
331 */
333 #endif /* IDCT_SCALING_SUPPORTED */
335 /* Report number of components in selected colorspace. */
336 /* Probably this should be in the color conversion module... */
337 switch (cinfo->out_color_space) {
338 case JCS_GRAYSCALE:
339 cinfo->out_color_components = 1;
340 break;
341 case JCS_RGB:
342 case JCS_EXT_RGB:
343 case JCS_EXT_RGBX:
344 case JCS_EXT_BGR:
345 case JCS_EXT_BGRX:
346 case JCS_EXT_XBGR:
347 case JCS_EXT_XRGB:
348 case JCS_EXT_RGBA:
349 case JCS_EXT_BGRA:
350 case JCS_EXT_ABGR:
351 case JCS_EXT_ARGB:
352 cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space];
353 break;
354 case JCS_YCbCr:
355 cinfo->out_color_components = 3;
356 break;
357 case JCS_CMYK:
358 case JCS_YCCK:
359 cinfo->out_color_components = 4;
360 break;
361 default: /* else must be same colorspace as in file */
362 cinfo->out_color_components = cinfo->num_components;
363 break;
364 }
365 cinfo->output_components = (cinfo->quantize_colors ? 1 :
366 cinfo->out_color_components);
368 /* See if upsampler will want to emit more than one row at a time */
369 if (use_merged_upsample(cinfo))
370 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
371 else
372 cinfo->rec_outbuf_height = 1;
373 }
376 /*
377 * Several decompression processes need to range-limit values to the range
378 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
379 * due to noise introduced by quantization, roundoff error, etc. These
380 * processes are inner loops and need to be as fast as possible. On most
381 * machines, particularly CPUs with pipelines or instruction prefetch,
382 * a (subscript-check-less) C table lookup
383 * x = sample_range_limit[x];
384 * is faster than explicit tests
385 * if (x < 0) x = 0;
386 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
387 * These processes all use a common table prepared by the routine below.
388 *
389 * For most steps we can mathematically guarantee that the initial value
390 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
391 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
392 * limiting step (just after the IDCT), a wildly out-of-range value is
393 * possible if the input data is corrupt. To avoid any chance of indexing
394 * off the end of memory and getting a bad-pointer trap, we perform the
395 * post-IDCT limiting thus:
396 * x = range_limit[x & MASK];
397 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
398 * samples. Under normal circumstances this is more than enough range and
399 * a correct output will be generated; with bogus input data the mask will
400 * cause wraparound, and we will safely generate a bogus-but-in-range output.
401 * For the post-IDCT step, we want to convert the data from signed to unsigned
402 * representation by adding CENTERJSAMPLE at the same time that we limit it.
403 * So the post-IDCT limiting table ends up looking like this:
404 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
405 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
406 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
407 * 0,1,...,CENTERJSAMPLE-1
408 * Negative inputs select values from the upper half of the table after
409 * masking.
410 *
411 * We can save some space by overlapping the start of the post-IDCT table
412 * with the simpler range limiting table. The post-IDCT table begins at
413 * sample_range_limit + CENTERJSAMPLE.
414 *
415 * Note that the table is allocated in near data space on PCs; it's small
416 * enough and used often enough to justify this.
417 */
419 LOCAL(void)
420 prepare_range_limit_table (j_decompress_ptr cinfo)
421 /* Allocate and fill in the sample_range_limit table */
422 {
423 JSAMPLE * table;
424 int i;
426 table = (JSAMPLE *)
427 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
428 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
429 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
430 cinfo->sample_range_limit = table;
431 /* First segment of "simple" table: limit[x] = 0 for x < 0 */
432 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE));
433 /* Main part of "simple" table: limit[x] = x */
434 for (i = 0; i <= MAXJSAMPLE; i++)
435 table[i] = (JSAMPLE) i;
436 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
437 /* End of simple table, rest of first half of post-IDCT table */
438 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
439 table[i] = MAXJSAMPLE;
440 /* Second half of post-IDCT table */
441 MEMZERO(table + (2 * (MAXJSAMPLE+1)),
442 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
443 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
444 cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
445 }
448 /*
449 * Master selection of decompression modules.
450 * This is done once at jpeg_start_decompress time. We determine
451 * which modules will be used and give them appropriate initialization calls.
452 * We also initialize the decompressor input side to begin consuming data.
453 *
454 * Since jpeg_read_header has finished, we know what is in the SOF
455 * and (first) SOS markers. We also have all the application parameter
456 * settings.
457 */
459 LOCAL(void)
460 master_selection (j_decompress_ptr cinfo)
461 {
462 my_master_ptr master = (my_master_ptr) cinfo->master;
463 boolean use_c_buffer;
464 long samplesperrow;
465 JDIMENSION jd_samplesperrow;
467 /* Initialize dimensions and other stuff */
468 jpeg_calc_output_dimensions(cinfo);
469 prepare_range_limit_table(cinfo);
471 /* Width of an output scanline must be representable as JDIMENSION. */
472 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
473 jd_samplesperrow = (JDIMENSION) samplesperrow;
474 if ((long) jd_samplesperrow != samplesperrow)
475 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
477 /* Initialize my private state */
478 master->pass_number = 0;
479 master->using_merged_upsample = use_merged_upsample(cinfo);
481 /* Color quantizer selection */
482 master->quantizer_1pass = NULL;
483 master->quantizer_2pass = NULL;
484 /* No mode changes if not using buffered-image mode. */
485 if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
486 cinfo->enable_1pass_quant = FALSE;
487 cinfo->enable_external_quant = FALSE;
488 cinfo->enable_2pass_quant = FALSE;
489 }
490 if (cinfo->quantize_colors) {
491 if (cinfo->raw_data_out)
492 ERREXIT(cinfo, JERR_NOTIMPL);
493 /* 2-pass quantizer only works in 3-component color space. */
494 if (cinfo->out_color_components != 3) {
495 cinfo->enable_1pass_quant = TRUE;
496 cinfo->enable_external_quant = FALSE;
497 cinfo->enable_2pass_quant = FALSE;
498 cinfo->colormap = NULL;
499 } else if (cinfo->colormap != NULL) {
500 cinfo->enable_external_quant = TRUE;
501 } else if (cinfo->two_pass_quantize) {
502 cinfo->enable_2pass_quant = TRUE;
503 } else {
504 cinfo->enable_1pass_quant = TRUE;
505 }
507 if (cinfo->enable_1pass_quant) {
508 #ifdef QUANT_1PASS_SUPPORTED
509 jinit_1pass_quantizer(cinfo);
510 master->quantizer_1pass = cinfo->cquantize;
511 #else
512 ERREXIT(cinfo, JERR_NOT_COMPILED);
513 #endif
514 }
516 /* We use the 2-pass code to map to external colormaps. */
517 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
518 #ifdef QUANT_2PASS_SUPPORTED
519 jinit_2pass_quantizer(cinfo);
520 master->quantizer_2pass = cinfo->cquantize;
521 #else
522 ERREXIT(cinfo, JERR_NOT_COMPILED);
523 #endif
524 }
525 /* If both quantizers are initialized, the 2-pass one is left active;
526 * this is necessary for starting with quantization to an external map.
527 */
528 }
530 /* Post-processing: in particular, color conversion first */
531 if (! cinfo->raw_data_out) {
532 if (master->using_merged_upsample) {
533 #ifdef UPSAMPLE_MERGING_SUPPORTED
534 jinit_merged_upsampler(cinfo); /* does color conversion too */
535 #else
536 ERREXIT(cinfo, JERR_NOT_COMPILED);
537 #endif
538 } else {
539 jinit_color_deconverter(cinfo);
540 jinit_upsampler(cinfo);
541 }
542 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
543 }
544 /* Inverse DCT */
545 jinit_inverse_dct(cinfo);
546 /* Entropy decoding: either Huffman or arithmetic coding. */
547 if (cinfo->arith_code) {
548 #ifdef D_ARITH_CODING_SUPPORTED
549 jinit_arith_decoder(cinfo);
550 #else
551 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
552 #endif
553 } else {
554 if (cinfo->progressive_mode) {
555 #ifdef D_PROGRESSIVE_SUPPORTED
556 jinit_phuff_decoder(cinfo);
557 #else
558 ERREXIT(cinfo, JERR_NOT_COMPILED);
559 #endif
560 } else
561 jinit_huff_decoder(cinfo);
562 }
564 /* Initialize principal buffer controllers. */
565 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
566 jinit_d_coef_controller(cinfo, use_c_buffer);
568 if (! cinfo->raw_data_out)
569 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
571 /* We can now tell the memory manager to allocate virtual arrays. */
572 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
574 /* Initialize input side of decompressor to consume first scan. */
575 (*cinfo->inputctl->start_input_pass) (cinfo);
577 #ifdef D_MULTISCAN_FILES_SUPPORTED
578 /* If jpeg_start_decompress will read the whole file, initialize
579 * progress monitoring appropriately. The input step is counted
580 * as one pass.
581 */
582 if (cinfo->progress != NULL && ! cinfo->buffered_image &&
583 cinfo->inputctl->has_multiple_scans) {
584 int nscans;
585 /* Estimate number of scans to set pass_limit. */
586 if (cinfo->progressive_mode) {
587 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
588 nscans = 2 + 3 * cinfo->num_components;
589 } else {
590 /* For a nonprogressive multiscan file, estimate 1 scan per component. */
591 nscans = cinfo->num_components;
592 }
593 cinfo->progress->pass_counter = 0L;
594 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
595 cinfo->progress->completed_passes = 0;
596 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
597 /* Count the input pass as done */
598 master->pass_number++;
599 }
600 #endif /* D_MULTISCAN_FILES_SUPPORTED */
601 }
604 /*
605 * Per-pass setup.
606 * This is called at the beginning of each output pass. We determine which
607 * modules will be active during this pass and give them appropriate
608 * start_pass calls. We also set is_dummy_pass to indicate whether this
609 * is a "real" output pass or a dummy pass for color quantization.
610 * (In the latter case, jdapistd.c will crank the pass to completion.)
611 */
613 METHODDEF(void)
614 prepare_for_output_pass (j_decompress_ptr cinfo)
615 {
616 my_master_ptr master = (my_master_ptr) cinfo->master;
618 if (master->pub.is_dummy_pass) {
619 #ifdef QUANT_2PASS_SUPPORTED
620 /* Final pass of 2-pass quantization */
621 master->pub.is_dummy_pass = FALSE;
622 (*cinfo->cquantize->start_pass) (cinfo, FALSE);
623 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
624 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
625 #else
626 ERREXIT(cinfo, JERR_NOT_COMPILED);
627 #endif /* QUANT_2PASS_SUPPORTED */
628 } else {
629 if (cinfo->quantize_colors && cinfo->colormap == NULL) {
630 /* Select new quantization method */
631 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
632 cinfo->cquantize = master->quantizer_2pass;
633 master->pub.is_dummy_pass = TRUE;
634 } else if (cinfo->enable_1pass_quant) {
635 cinfo->cquantize = master->quantizer_1pass;
636 } else {
637 ERREXIT(cinfo, JERR_MODE_CHANGE);
638 }
639 }
640 (*cinfo->idct->start_pass) (cinfo);
641 (*cinfo->coef->start_output_pass) (cinfo);
642 if (! cinfo->raw_data_out) {
643 if (! master->using_merged_upsample)
644 (*cinfo->cconvert->start_pass) (cinfo);
645 (*cinfo->upsample->start_pass) (cinfo);
646 if (cinfo->quantize_colors)
647 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
648 (*cinfo->post->start_pass) (cinfo,
649 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
650 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
651 }
652 }
654 /* Set up progress monitor's pass info if present */
655 if (cinfo->progress != NULL) {
656 cinfo->progress->completed_passes = master->pass_number;
657 cinfo->progress->total_passes = master->pass_number +
658 (master->pub.is_dummy_pass ? 2 : 1);
659 /* In buffered-image mode, we assume one more output pass if EOI not
660 * yet reached, but no more passes if EOI has been reached.
661 */
662 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
663 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
664 }
665 }
666 }
669 /*
670 * Finish up at end of an output pass.
671 */
673 METHODDEF(void)
674 finish_output_pass (j_decompress_ptr cinfo)
675 {
676 my_master_ptr master = (my_master_ptr) cinfo->master;
678 if (cinfo->quantize_colors)
679 (*cinfo->cquantize->finish_pass) (cinfo);
680 master->pass_number++;
681 }
684 #ifdef D_MULTISCAN_FILES_SUPPORTED
686 /*
687 * Switch to a new external colormap between output passes.
688 */
690 GLOBAL(void)
691 jpeg_new_colormap (j_decompress_ptr cinfo)
692 {
693 my_master_ptr master = (my_master_ptr) cinfo->master;
695 /* Prevent application from calling me at wrong times */
696 if (cinfo->global_state != DSTATE_BUFIMAGE)
697 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
699 if (cinfo->quantize_colors && cinfo->enable_external_quant &&
700 cinfo->colormap != NULL) {
701 /* Select 2-pass quantizer for external colormap use */
702 cinfo->cquantize = master->quantizer_2pass;
703 /* Notify quantizer of colormap change */
704 (*cinfo->cquantize->new_color_map) (cinfo);
705 master->pub.is_dummy_pass = FALSE; /* just in case */
706 } else
707 ERREXIT(cinfo, JERR_MODE_CHANGE);
708 }
710 #endif /* D_MULTISCAN_FILES_SUPPORTED */
713 /*
714 * Initialize master decompression control and select active modules.
715 * This is performed at the start of jpeg_start_decompress.
716 */
718 GLOBAL(void)
719 jinit_master_decompress (j_decompress_ptr cinfo)
720 {
721 my_master_ptr master;
723 master = (my_master_ptr)
724 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
725 SIZEOF(my_decomp_master));
726 cinfo->master = (struct jpeg_decomp_master *) master;
727 master->pub.prepare_for_output_pass = prepare_for_output_pass;
728 master->pub.finish_output_pass = finish_output_pass;
730 master->pub.is_dummy_pass = FALSE;
732 master_selection(cinfo);
733 }
