Line data Source code
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, 2016, D. R. Commander.
9 : * Copyright (C) 2013, Linaro Limited.
10 : * Copyright (C) 2015, Google, Inc.
11 : * For conditions of distribution and use, see the accompanying README.ijg
12 : * file.
13 : *
14 : * This file contains master control logic for the JPEG decompressor.
15 : * These routines are concerned with selecting the modules to be executed
16 : * and with determining the number of passes and the work to be done in each
17 : * pass.
18 : */
19 :
20 : #define JPEG_INTERNALS
21 : #include "jinclude.h"
22 : #include "jpeglib.h"
23 : #include "jpegcomp.h"
24 : #include "jdmaster.h"
25 : #include "jsimd.h"
26 :
27 :
28 : /*
29 : * Determine whether merged upsample/color conversion should be used.
30 : * CRUCIAL: this must match the actual capabilities of jdmerge.c!
31 : */
32 :
33 : LOCAL(boolean)
34 0 : use_merged_upsample (j_decompress_ptr cinfo)
35 : {
36 : #ifdef UPSAMPLE_MERGING_SUPPORTED
37 : /* Merging is the equivalent of plain box-filter upsampling */
38 0 : if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
39 0 : return FALSE;
40 : /* jdmerge.c only supports YCC=>RGB and YCC=>RGB565 color conversion */
41 0 : if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
42 0 : (cinfo->out_color_space != JCS_RGB &&
43 0 : cinfo->out_color_space != JCS_RGB565 &&
44 0 : cinfo->out_color_space != JCS_EXT_RGB &&
45 0 : cinfo->out_color_space != JCS_EXT_RGBX &&
46 0 : cinfo->out_color_space != JCS_EXT_BGR &&
47 0 : cinfo->out_color_space != JCS_EXT_BGRX &&
48 0 : cinfo->out_color_space != JCS_EXT_XBGR &&
49 0 : cinfo->out_color_space != JCS_EXT_XRGB &&
50 0 : cinfo->out_color_space != JCS_EXT_RGBA &&
51 0 : cinfo->out_color_space != JCS_EXT_BGRA &&
52 0 : cinfo->out_color_space != JCS_EXT_ABGR &&
53 0 : cinfo->out_color_space != JCS_EXT_ARGB))
54 0 : return FALSE;
55 0 : if ((cinfo->out_color_space == JCS_RGB565 &&
56 0 : cinfo->out_color_components != 3) ||
57 0 : (cinfo->out_color_space != JCS_RGB565 &&
58 0 : cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space]))
59 0 : return FALSE;
60 : /* and it only handles 2h1v or 2h2v sampling ratios */
61 0 : if (cinfo->comp_info[0].h_samp_factor != 2 ||
62 0 : cinfo->comp_info[1].h_samp_factor != 1 ||
63 0 : cinfo->comp_info[2].h_samp_factor != 1 ||
64 0 : cinfo->comp_info[0].v_samp_factor > 2 ||
65 0 : cinfo->comp_info[1].v_samp_factor != 1 ||
66 0 : cinfo->comp_info[2].v_samp_factor != 1)
67 0 : return FALSE;
68 : /* furthermore, it doesn't work if we've scaled the IDCTs differently */
69 0 : if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
70 0 : cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
71 0 : cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size)
72 0 : return FALSE;
73 : #ifdef WITH_SIMD
74 : /* If YCbCr-to-RGB color conversion is SIMD-accelerated but merged upsampling
75 : isn't, then disabling merged upsampling is likely to be faster when
76 : decompressing YCbCr JPEG images. */
77 0 : if (!jsimd_can_h2v2_merged_upsample() && !jsimd_can_h2v1_merged_upsample() &&
78 0 : jsimd_can_ycc_rgb() && cinfo->jpeg_color_space == JCS_YCbCr &&
79 0 : (cinfo->out_color_space == JCS_RGB ||
80 0 : (cinfo->out_color_space >= JCS_EXT_RGB &&
81 0 : cinfo->out_color_space <= JCS_EXT_ARGB)))
82 0 : return FALSE;
83 : #endif
84 : /* ??? also need to test for upsample-time rescaling, when & if supported */
85 0 : return TRUE; /* by golly, it'll work... */
86 : #else
87 : return FALSE;
88 : #endif
89 : }
90 :
91 :
92 : /*
93 : * Compute output image dimensions and related values.
94 : * NOTE: this is exported for possible use by application.
95 : * Hence it mustn't do anything that can't be done twice.
96 : */
97 :
98 : #if JPEG_LIB_VERSION >= 80
99 : GLOBAL(void)
100 : #else
101 : LOCAL(void)
102 : #endif
103 0 : jpeg_core_output_dimensions (j_decompress_ptr cinfo)
104 : /* Do computations that are needed before master selection phase.
105 : * This function is used for transcoding and full decompression.
106 : */
107 : {
108 : #ifdef IDCT_SCALING_SUPPORTED
109 : int ci;
110 : jpeg_component_info *compptr;
111 :
112 : /* Compute actual output image dimensions and DCT scaling choices. */
113 0 : if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) {
114 : /* Provide 1/block_size scaling */
115 0 : cinfo->output_width = (JDIMENSION)
116 0 : jdiv_round_up((long) cinfo->image_width, (long) DCTSIZE);
117 0 : cinfo->output_height = (JDIMENSION)
118 0 : jdiv_round_up((long) cinfo->image_height, (long) DCTSIZE);
119 0 : cinfo->_min_DCT_h_scaled_size = 1;
120 0 : cinfo->_min_DCT_v_scaled_size = 1;
121 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) {
122 : /* Provide 2/block_size scaling */
123 0 : cinfo->output_width = (JDIMENSION)
124 0 : jdiv_round_up((long) cinfo->image_width * 2L, (long) DCTSIZE);
125 0 : cinfo->output_height = (JDIMENSION)
126 0 : jdiv_round_up((long) cinfo->image_height * 2L, (long) DCTSIZE);
127 0 : cinfo->_min_DCT_h_scaled_size = 2;
128 0 : cinfo->_min_DCT_v_scaled_size = 2;
129 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) {
130 : /* Provide 3/block_size scaling */
131 0 : cinfo->output_width = (JDIMENSION)
132 0 : jdiv_round_up((long) cinfo->image_width * 3L, (long) DCTSIZE);
133 0 : cinfo->output_height = (JDIMENSION)
134 0 : jdiv_round_up((long) cinfo->image_height * 3L, (long) DCTSIZE);
135 0 : cinfo->_min_DCT_h_scaled_size = 3;
136 0 : cinfo->_min_DCT_v_scaled_size = 3;
137 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) {
138 : /* Provide 4/block_size scaling */
139 0 : cinfo->output_width = (JDIMENSION)
140 0 : jdiv_round_up((long) cinfo->image_width * 4L, (long) DCTSIZE);
141 0 : cinfo->output_height = (JDIMENSION)
142 0 : jdiv_round_up((long) cinfo->image_height * 4L, (long) DCTSIZE);
143 0 : cinfo->_min_DCT_h_scaled_size = 4;
144 0 : cinfo->_min_DCT_v_scaled_size = 4;
145 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) {
146 : /* Provide 5/block_size scaling */
147 0 : cinfo->output_width = (JDIMENSION)
148 0 : jdiv_round_up((long) cinfo->image_width * 5L, (long) DCTSIZE);
149 0 : cinfo->output_height = (JDIMENSION)
150 0 : jdiv_round_up((long) cinfo->image_height * 5L, (long) DCTSIZE);
151 0 : cinfo->_min_DCT_h_scaled_size = 5;
152 0 : cinfo->_min_DCT_v_scaled_size = 5;
153 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) {
154 : /* Provide 6/block_size scaling */
155 0 : cinfo->output_width = (JDIMENSION)
156 0 : jdiv_round_up((long) cinfo->image_width * 6L, (long) DCTSIZE);
157 0 : cinfo->output_height = (JDIMENSION)
158 0 : jdiv_round_up((long) cinfo->image_height * 6L, (long) DCTSIZE);
159 0 : cinfo->_min_DCT_h_scaled_size = 6;
160 0 : cinfo->_min_DCT_v_scaled_size = 6;
161 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) {
162 : /* Provide 7/block_size scaling */
163 0 : cinfo->output_width = (JDIMENSION)
164 0 : jdiv_round_up((long) cinfo->image_width * 7L, (long) DCTSIZE);
165 0 : cinfo->output_height = (JDIMENSION)
166 0 : jdiv_round_up((long) cinfo->image_height * 7L, (long) DCTSIZE);
167 0 : cinfo->_min_DCT_h_scaled_size = 7;
168 0 : cinfo->_min_DCT_v_scaled_size = 7;
169 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) {
170 : /* Provide 8/block_size scaling */
171 0 : cinfo->output_width = (JDIMENSION)
172 0 : jdiv_round_up((long) cinfo->image_width * 8L, (long) DCTSIZE);
173 0 : cinfo->output_height = (JDIMENSION)
174 0 : jdiv_round_up((long) cinfo->image_height * 8L, (long) DCTSIZE);
175 0 : cinfo->_min_DCT_h_scaled_size = 8;
176 0 : cinfo->_min_DCT_v_scaled_size = 8;
177 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) {
178 : /* Provide 9/block_size scaling */
179 0 : cinfo->output_width = (JDIMENSION)
180 0 : jdiv_round_up((long) cinfo->image_width * 9L, (long) DCTSIZE);
181 0 : cinfo->output_height = (JDIMENSION)
182 0 : jdiv_round_up((long) cinfo->image_height * 9L, (long) DCTSIZE);
183 0 : cinfo->_min_DCT_h_scaled_size = 9;
184 0 : cinfo->_min_DCT_v_scaled_size = 9;
185 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) {
186 : /* Provide 10/block_size scaling */
187 0 : cinfo->output_width = (JDIMENSION)
188 0 : jdiv_round_up((long) cinfo->image_width * 10L, (long) DCTSIZE);
189 0 : cinfo->output_height = (JDIMENSION)
190 0 : jdiv_round_up((long) cinfo->image_height * 10L, (long) DCTSIZE);
191 0 : cinfo->_min_DCT_h_scaled_size = 10;
192 0 : cinfo->_min_DCT_v_scaled_size = 10;
193 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) {
194 : /* Provide 11/block_size scaling */
195 0 : cinfo->output_width = (JDIMENSION)
196 0 : jdiv_round_up((long) cinfo->image_width * 11L, (long) DCTSIZE);
197 0 : cinfo->output_height = (JDIMENSION)
198 0 : jdiv_round_up((long) cinfo->image_height * 11L, (long) DCTSIZE);
199 0 : cinfo->_min_DCT_h_scaled_size = 11;
200 0 : cinfo->_min_DCT_v_scaled_size = 11;
201 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) {
202 : /* Provide 12/block_size scaling */
203 0 : cinfo->output_width = (JDIMENSION)
204 0 : jdiv_round_up((long) cinfo->image_width * 12L, (long) DCTSIZE);
205 0 : cinfo->output_height = (JDIMENSION)
206 0 : jdiv_round_up((long) cinfo->image_height * 12L, (long) DCTSIZE);
207 0 : cinfo->_min_DCT_h_scaled_size = 12;
208 0 : cinfo->_min_DCT_v_scaled_size = 12;
209 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) {
210 : /* Provide 13/block_size scaling */
211 0 : cinfo->output_width = (JDIMENSION)
212 0 : jdiv_round_up((long) cinfo->image_width * 13L, (long) DCTSIZE);
213 0 : cinfo->output_height = (JDIMENSION)
214 0 : jdiv_round_up((long) cinfo->image_height * 13L, (long) DCTSIZE);
215 0 : cinfo->_min_DCT_h_scaled_size = 13;
216 0 : cinfo->_min_DCT_v_scaled_size = 13;
217 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) {
218 : /* Provide 14/block_size scaling */
219 0 : cinfo->output_width = (JDIMENSION)
220 0 : jdiv_round_up((long) cinfo->image_width * 14L, (long) DCTSIZE);
221 0 : cinfo->output_height = (JDIMENSION)
222 0 : jdiv_round_up((long) cinfo->image_height * 14L, (long) DCTSIZE);
223 0 : cinfo->_min_DCT_h_scaled_size = 14;
224 0 : cinfo->_min_DCT_v_scaled_size = 14;
225 0 : } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) {
226 : /* Provide 15/block_size scaling */
227 0 : cinfo->output_width = (JDIMENSION)
228 0 : jdiv_round_up((long) cinfo->image_width * 15L, (long) DCTSIZE);
229 0 : cinfo->output_height = (JDIMENSION)
230 0 : jdiv_round_up((long) cinfo->image_height * 15L, (long) DCTSIZE);
231 0 : cinfo->_min_DCT_h_scaled_size = 15;
232 0 : cinfo->_min_DCT_v_scaled_size = 15;
233 : } else {
234 : /* Provide 16/block_size scaling */
235 0 : cinfo->output_width = (JDIMENSION)
236 0 : jdiv_round_up((long) cinfo->image_width * 16L, (long) DCTSIZE);
237 0 : cinfo->output_height = (JDIMENSION)
238 0 : jdiv_round_up((long) cinfo->image_height * 16L, (long) DCTSIZE);
239 0 : cinfo->_min_DCT_h_scaled_size = 16;
240 0 : cinfo->_min_DCT_v_scaled_size = 16;
241 : }
242 :
243 : /* Recompute dimensions of components */
244 0 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
245 0 : ci++, compptr++) {
246 0 : compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size;
247 0 : compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size;
248 : }
249 :
250 : #else /* !IDCT_SCALING_SUPPORTED */
251 :
252 : /* Hardwire it to "no scaling" */
253 : cinfo->output_width = cinfo->image_width;
254 : cinfo->output_height = cinfo->image_height;
255 : /* jdinput.c has already initialized DCT_scaled_size,
256 : * and has computed unscaled downsampled_width and downsampled_height.
257 : */
258 :
259 : #endif /* IDCT_SCALING_SUPPORTED */
260 0 : }
261 :
262 :
263 : /*
264 : * Compute output image dimensions and related values.
265 : * NOTE: this is exported for possible use by application.
266 : * Hence it mustn't do anything that can't be done twice.
267 : * Also note that it may be called before the master module is initialized!
268 : */
269 :
270 : GLOBAL(void)
271 0 : jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
272 : /* Do computations that are needed before master selection phase */
273 : {
274 : #ifdef IDCT_SCALING_SUPPORTED
275 : int ci;
276 : jpeg_component_info *compptr;
277 : #endif
278 :
279 : /* Prevent application from calling me at wrong times */
280 0 : if (cinfo->global_state != DSTATE_READY)
281 0 : ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
282 :
283 : /* Compute core output image dimensions and DCT scaling choices. */
284 0 : jpeg_core_output_dimensions(cinfo);
285 :
286 : #ifdef IDCT_SCALING_SUPPORTED
287 :
288 : /* In selecting the actual DCT scaling for each component, we try to
289 : * scale up the chroma components via IDCT scaling rather than upsampling.
290 : * This saves time if the upsampler gets to use 1:1 scaling.
291 : * Note this code adapts subsampling ratios which are powers of 2.
292 : */
293 0 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
294 0 : ci++, compptr++) {
295 0 : int ssize = cinfo->_min_DCT_scaled_size;
296 0 : while (ssize < DCTSIZE &&
297 0 : ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) %
298 0 : (compptr->h_samp_factor * ssize * 2) == 0) &&
299 0 : ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) %
300 0 : (compptr->v_samp_factor * ssize * 2) == 0)) {
301 0 : ssize = ssize * 2;
302 : }
303 : #if JPEG_LIB_VERSION >= 70
304 : compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize;
305 : #else
306 0 : compptr->DCT_scaled_size = ssize;
307 : #endif
308 : }
309 :
310 : /* Recompute downsampled dimensions of components;
311 : * application needs to know these if using raw downsampled data.
312 : */
313 0 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
314 0 : ci++, compptr++) {
315 : /* Size in samples, after IDCT scaling */
316 0 : compptr->downsampled_width = (JDIMENSION)
317 0 : jdiv_round_up((long) cinfo->image_width *
318 0 : (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size),
319 0 : (long) (cinfo->max_h_samp_factor * DCTSIZE));
320 0 : compptr->downsampled_height = (JDIMENSION)
321 0 : jdiv_round_up((long) cinfo->image_height *
322 0 : (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size),
323 0 : (long) (cinfo->max_v_samp_factor * DCTSIZE));
324 : }
325 :
326 : #else /* !IDCT_SCALING_SUPPORTED */
327 :
328 : /* Hardwire it to "no scaling" */
329 : cinfo->output_width = cinfo->image_width;
330 : cinfo->output_height = cinfo->image_height;
331 : /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
332 : * and has computed unscaled downsampled_width and downsampled_height.
333 : */
334 :
335 : #endif /* IDCT_SCALING_SUPPORTED */
336 :
337 : /* Report number of components in selected colorspace. */
338 : /* Probably this should be in the color conversion module... */
339 0 : switch (cinfo->out_color_space) {
340 : case JCS_GRAYSCALE:
341 0 : cinfo->out_color_components = 1;
342 0 : break;
343 : case JCS_RGB:
344 : case JCS_EXT_RGB:
345 : case JCS_EXT_RGBX:
346 : case JCS_EXT_BGR:
347 : case JCS_EXT_BGRX:
348 : case JCS_EXT_XBGR:
349 : case JCS_EXT_XRGB:
350 : case JCS_EXT_RGBA:
351 : case JCS_EXT_BGRA:
352 : case JCS_EXT_ABGR:
353 : case JCS_EXT_ARGB:
354 0 : cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space];
355 0 : break;
356 : case JCS_YCbCr:
357 : case JCS_RGB565:
358 0 : cinfo->out_color_components = 3;
359 0 : break;
360 : case JCS_CMYK:
361 : case JCS_YCCK:
362 0 : cinfo->out_color_components = 4;
363 0 : break;
364 : default: /* else must be same colorspace as in file */
365 0 : cinfo->out_color_components = cinfo->num_components;
366 0 : break;
367 : }
368 0 : cinfo->output_components = (cinfo->quantize_colors ? 1 :
369 : cinfo->out_color_components);
370 :
371 : /* See if upsampler will want to emit more than one row at a time */
372 0 : if (use_merged_upsample(cinfo))
373 0 : cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
374 : else
375 0 : cinfo->rec_outbuf_height = 1;
376 0 : }
377 :
378 :
379 : /*
380 : * Several decompression processes need to range-limit values to the range
381 : * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
382 : * due to noise introduced by quantization, roundoff error, etc. These
383 : * processes are inner loops and need to be as fast as possible. On most
384 : * machines, particularly CPUs with pipelines or instruction prefetch,
385 : * a (subscript-check-less) C table lookup
386 : * x = sample_range_limit[x];
387 : * is faster than explicit tests
388 : * if (x < 0) x = 0;
389 : * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
390 : * These processes all use a common table prepared by the routine below.
391 : *
392 : * For most steps we can mathematically guarantee that the initial value
393 : * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
394 : * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
395 : * limiting step (just after the IDCT), a wildly out-of-range value is
396 : * possible if the input data is corrupt. To avoid any chance of indexing
397 : * off the end of memory and getting a bad-pointer trap, we perform the
398 : * post-IDCT limiting thus:
399 : * x = range_limit[x & MASK];
400 : * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
401 : * samples. Under normal circumstances this is more than enough range and
402 : * a correct output will be generated; with bogus input data the mask will
403 : * cause wraparound, and we will safely generate a bogus-but-in-range output.
404 : * For the post-IDCT step, we want to convert the data from signed to unsigned
405 : * representation by adding CENTERJSAMPLE at the same time that we limit it.
406 : * So the post-IDCT limiting table ends up looking like this:
407 : * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
408 : * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
409 : * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
410 : * 0,1,...,CENTERJSAMPLE-1
411 : * Negative inputs select values from the upper half of the table after
412 : * masking.
413 : *
414 : * We can save some space by overlapping the start of the post-IDCT table
415 : * with the simpler range limiting table. The post-IDCT table begins at
416 : * sample_range_limit + CENTERJSAMPLE.
417 : */
418 :
419 : LOCAL(void)
420 0 : 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;
425 :
426 0 : table = (JSAMPLE *)
427 0 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
428 : (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * sizeof(JSAMPLE));
429 0 : table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
430 0 : cinfo->sample_range_limit = table;
431 : /* First segment of "simple" table: limit[x] = 0 for x < 0 */
432 0 : MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * sizeof(JSAMPLE));
433 : /* Main part of "simple" table: limit[x] = x */
434 0 : for (i = 0; i <= MAXJSAMPLE; i++)
435 0 : table[i] = (JSAMPLE) i;
436 0 : table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
437 : /* End of simple table, rest of first half of post-IDCT table */
438 0 : for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
439 0 : table[i] = MAXJSAMPLE;
440 : /* Second half of post-IDCT table */
441 0 : MEMZERO(table + (2 * (MAXJSAMPLE+1)),
442 : (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * sizeof(JSAMPLE));
443 0 : MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
444 : cinfo->sample_range_limit, CENTERJSAMPLE * sizeof(JSAMPLE));
445 0 : }
446 :
447 :
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 : */
458 :
459 : LOCAL(void)
460 0 : master_selection (j_decompress_ptr cinfo)
461 : {
462 0 : my_master_ptr master = (my_master_ptr) cinfo->master;
463 : boolean use_c_buffer;
464 : long samplesperrow;
465 : JDIMENSION jd_samplesperrow;
466 :
467 : /* Initialize dimensions and other stuff */
468 0 : jpeg_calc_output_dimensions(cinfo);
469 0 : prepare_range_limit_table(cinfo);
470 :
471 : /* Width of an output scanline must be representable as JDIMENSION. */
472 0 : samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
473 0 : jd_samplesperrow = (JDIMENSION) samplesperrow;
474 0 : if ((long) jd_samplesperrow != samplesperrow)
475 0 : ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
476 :
477 : /* Initialize my private state */
478 0 : master->pass_number = 0;
479 0 : master->using_merged_upsample = use_merged_upsample(cinfo);
480 :
481 : /* Color quantizer selection */
482 0 : master->quantizer_1pass = NULL;
483 0 : master->quantizer_2pass = NULL;
484 : /* No mode changes if not using buffered-image mode. */
485 0 : if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
486 0 : cinfo->enable_1pass_quant = FALSE;
487 0 : cinfo->enable_external_quant = FALSE;
488 0 : cinfo->enable_2pass_quant = FALSE;
489 : }
490 0 : if (cinfo->quantize_colors) {
491 0 : if (cinfo->raw_data_out)
492 0 : ERREXIT(cinfo, JERR_NOTIMPL);
493 : /* 2-pass quantizer only works in 3-component color space. */
494 0 : if (cinfo->out_color_components != 3) {
495 0 : cinfo->enable_1pass_quant = TRUE;
496 0 : cinfo->enable_external_quant = FALSE;
497 0 : cinfo->enable_2pass_quant = FALSE;
498 0 : cinfo->colormap = NULL;
499 0 : } else if (cinfo->colormap != NULL) {
500 0 : cinfo->enable_external_quant = TRUE;
501 0 : } else if (cinfo->two_pass_quantize) {
502 0 : cinfo->enable_2pass_quant = TRUE;
503 : } else {
504 0 : cinfo->enable_1pass_quant = TRUE;
505 : }
506 :
507 0 : if (cinfo->enable_1pass_quant) {
508 : #ifdef QUANT_1PASS_SUPPORTED
509 0 : jinit_1pass_quantizer(cinfo);
510 0 : master->quantizer_1pass = cinfo->cquantize;
511 : #else
512 : ERREXIT(cinfo, JERR_NOT_COMPILED);
513 : #endif
514 : }
515 :
516 : /* We use the 2-pass code to map to external colormaps. */
517 0 : if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
518 : #ifdef QUANT_2PASS_SUPPORTED
519 0 : jinit_2pass_quantizer(cinfo);
520 0 : 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 : }
529 :
530 : /* Post-processing: in particular, color conversion first */
531 0 : if (! cinfo->raw_data_out) {
532 0 : if (master->using_merged_upsample) {
533 : #ifdef UPSAMPLE_MERGING_SUPPORTED
534 0 : jinit_merged_upsampler(cinfo); /* does color conversion too */
535 : #else
536 : ERREXIT(cinfo, JERR_NOT_COMPILED);
537 : #endif
538 : } else {
539 0 : jinit_color_deconverter(cinfo);
540 0 : jinit_upsampler(cinfo);
541 : }
542 0 : jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
543 : }
544 : /* Inverse DCT */
545 0 : jinit_inverse_dct(cinfo);
546 : /* Entropy decoding: either Huffman or arithmetic coding. */
547 0 : if (cinfo->arith_code) {
548 : #ifdef D_ARITH_CODING_SUPPORTED
549 : jinit_arith_decoder(cinfo);
550 : #else
551 0 : ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
552 : #endif
553 : } else {
554 0 : if (cinfo->progressive_mode) {
555 : #ifdef D_PROGRESSIVE_SUPPORTED
556 0 : jinit_phuff_decoder(cinfo);
557 : #else
558 : ERREXIT(cinfo, JERR_NOT_COMPILED);
559 : #endif
560 : } else
561 0 : jinit_huff_decoder(cinfo);
562 : }
563 :
564 : /* Initialize principal buffer controllers. */
565 0 : use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
566 0 : jinit_d_coef_controller(cinfo, use_c_buffer);
567 :
568 0 : if (! cinfo->raw_data_out)
569 0 : jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
570 :
571 : /* We can now tell the memory manager to allocate virtual arrays. */
572 0 : (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
573 :
574 : /* Initialize input side of decompressor to consume first scan. */
575 0 : (*cinfo->inputctl->start_input_pass) (cinfo);
576 :
577 : /* Set the first and last iMCU columns to decompress from single-scan images.
578 : * By default, decompress all of the iMCU columns.
579 : */
580 0 : cinfo->master->first_iMCU_col = 0;
581 0 : cinfo->master->last_iMCU_col = cinfo->MCUs_per_row - 1;
582 :
583 : #ifdef D_MULTISCAN_FILES_SUPPORTED
584 : /* If jpeg_start_decompress will read the whole file, initialize
585 : * progress monitoring appropriately. The input step is counted
586 : * as one pass.
587 : */
588 0 : if (cinfo->progress != NULL && ! cinfo->buffered_image &&
589 0 : cinfo->inputctl->has_multiple_scans) {
590 : int nscans;
591 : /* Estimate number of scans to set pass_limit. */
592 0 : if (cinfo->progressive_mode) {
593 : /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
594 0 : nscans = 2 + 3 * cinfo->num_components;
595 : } else {
596 : /* For a nonprogressive multiscan file, estimate 1 scan per component. */
597 0 : nscans = cinfo->num_components;
598 : }
599 0 : cinfo->progress->pass_counter = 0L;
600 0 : cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
601 0 : cinfo->progress->completed_passes = 0;
602 0 : cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
603 : /* Count the input pass as done */
604 0 : master->pass_number++;
605 : }
606 : #endif /* D_MULTISCAN_FILES_SUPPORTED */
607 0 : }
608 :
609 :
610 : /*
611 : * Per-pass setup.
612 : * This is called at the beginning of each output pass. We determine which
613 : * modules will be active during this pass and give them appropriate
614 : * start_pass calls. We also set is_dummy_pass to indicate whether this
615 : * is a "real" output pass or a dummy pass for color quantization.
616 : * (In the latter case, jdapistd.c will crank the pass to completion.)
617 : */
618 :
619 : METHODDEF(void)
620 0 : prepare_for_output_pass (j_decompress_ptr cinfo)
621 : {
622 0 : my_master_ptr master = (my_master_ptr) cinfo->master;
623 :
624 0 : if (master->pub.is_dummy_pass) {
625 : #ifdef QUANT_2PASS_SUPPORTED
626 : /* Final pass of 2-pass quantization */
627 0 : master->pub.is_dummy_pass = FALSE;
628 0 : (*cinfo->cquantize->start_pass) (cinfo, FALSE);
629 0 : (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
630 0 : (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
631 : #else
632 : ERREXIT(cinfo, JERR_NOT_COMPILED);
633 : #endif /* QUANT_2PASS_SUPPORTED */
634 : } else {
635 0 : if (cinfo->quantize_colors && cinfo->colormap == NULL) {
636 : /* Select new quantization method */
637 0 : if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
638 0 : cinfo->cquantize = master->quantizer_2pass;
639 0 : master->pub.is_dummy_pass = TRUE;
640 0 : } else if (cinfo->enable_1pass_quant) {
641 0 : cinfo->cquantize = master->quantizer_1pass;
642 : } else {
643 0 : ERREXIT(cinfo, JERR_MODE_CHANGE);
644 : }
645 : }
646 0 : (*cinfo->idct->start_pass) (cinfo);
647 0 : (*cinfo->coef->start_output_pass) (cinfo);
648 0 : if (! cinfo->raw_data_out) {
649 0 : if (! master->using_merged_upsample)
650 0 : (*cinfo->cconvert->start_pass) (cinfo);
651 0 : (*cinfo->upsample->start_pass) (cinfo);
652 0 : if (cinfo->quantize_colors)
653 0 : (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
654 0 : (*cinfo->post->start_pass) (cinfo,
655 0 : (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
656 0 : (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
657 : }
658 : }
659 :
660 : /* Set up progress monitor's pass info if present */
661 0 : if (cinfo->progress != NULL) {
662 0 : cinfo->progress->completed_passes = master->pass_number;
663 0 : cinfo->progress->total_passes = master->pass_number +
664 0 : (master->pub.is_dummy_pass ? 2 : 1);
665 : /* In buffered-image mode, we assume one more output pass if EOI not
666 : * yet reached, but no more passes if EOI has been reached.
667 : */
668 0 : if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
669 0 : cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
670 : }
671 : }
672 0 : }
673 :
674 :
675 : /*
676 : * Finish up at end of an output pass.
677 : */
678 :
679 : METHODDEF(void)
680 0 : finish_output_pass (j_decompress_ptr cinfo)
681 : {
682 0 : my_master_ptr master = (my_master_ptr) cinfo->master;
683 :
684 0 : if (cinfo->quantize_colors)
685 0 : (*cinfo->cquantize->finish_pass) (cinfo);
686 0 : master->pass_number++;
687 0 : }
688 :
689 :
690 : #ifdef D_MULTISCAN_FILES_SUPPORTED
691 :
692 : /*
693 : * Switch to a new external colormap between output passes.
694 : */
695 :
696 : GLOBAL(void)
697 0 : jpeg_new_colormap (j_decompress_ptr cinfo)
698 : {
699 0 : my_master_ptr master = (my_master_ptr) cinfo->master;
700 :
701 : /* Prevent application from calling me at wrong times */
702 0 : if (cinfo->global_state != DSTATE_BUFIMAGE)
703 0 : ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
704 :
705 0 : if (cinfo->quantize_colors && cinfo->enable_external_quant &&
706 0 : cinfo->colormap != NULL) {
707 : /* Select 2-pass quantizer for external colormap use */
708 0 : cinfo->cquantize = master->quantizer_2pass;
709 : /* Notify quantizer of colormap change */
710 0 : (*cinfo->cquantize->new_color_map) (cinfo);
711 0 : master->pub.is_dummy_pass = FALSE; /* just in case */
712 : } else
713 0 : ERREXIT(cinfo, JERR_MODE_CHANGE);
714 0 : }
715 :
716 : #endif /* D_MULTISCAN_FILES_SUPPORTED */
717 :
718 :
719 : /*
720 : * Initialize master decompression control and select active modules.
721 : * This is performed at the start of jpeg_start_decompress.
722 : */
723 :
724 : GLOBAL(void)
725 0 : jinit_master_decompress (j_decompress_ptr cinfo)
726 : {
727 0 : my_master_ptr master = (my_master_ptr) cinfo->master;
728 :
729 0 : master->pub.prepare_for_output_pass = prepare_for_output_pass;
730 0 : master->pub.finish_output_pass = finish_output_pass;
731 :
732 0 : master->pub.is_dummy_pass = FALSE;
733 0 : master->pub.jinit_upsampler_no_alloc = FALSE;
734 :
735 0 : master_selection(cinfo);
736 0 : }
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