/proc/self/cwd/external/libjpeg_turbo/jdmainct.c
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1 | | /* |
2 | | * jdmainct.c |
3 | | * |
4 | | * This file was part of the Independent JPEG Group's software: |
5 | | * Copyright (C) 1994-1996, Thomas G. Lane. |
6 | | * libjpeg-turbo Modifications: |
7 | | * Copyright (C) 2010, 2016, D. R. Commander. |
8 | | * For conditions of distribution and use, see the accompanying README.ijg |
9 | | * file. |
10 | | * |
11 | | * This file contains the main buffer controller for decompression. |
12 | | * The main buffer lies between the JPEG decompressor proper and the |
13 | | * post-processor; it holds downsampled data in the JPEG colorspace. |
14 | | * |
15 | | * Note that this code is bypassed in raw-data mode, since the application |
16 | | * supplies the equivalent of the main buffer in that case. |
17 | | */ |
18 | | |
19 | | #include "jinclude.h" |
20 | | #include "jdmainct.h" |
21 | | #include "jconfigint.h" |
22 | | |
23 | | |
24 | | /* |
25 | | * In the current system design, the main buffer need never be a full-image |
26 | | * buffer; any full-height buffers will be found inside the coefficient or |
27 | | * postprocessing controllers. Nonetheless, the main controller is not |
28 | | * trivial. Its responsibility is to provide context rows for upsampling/ |
29 | | * rescaling, and doing this in an efficient fashion is a bit tricky. |
30 | | * |
31 | | * Postprocessor input data is counted in "row groups". A row group |
32 | | * is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size) |
33 | | * sample rows of each component. (We require DCT_scaled_size values to be |
34 | | * chosen such that these numbers are integers. In practice DCT_scaled_size |
35 | | * values will likely be powers of two, so we actually have the stronger |
36 | | * condition that DCT_scaled_size / min_DCT_scaled_size is an integer.) |
37 | | * Upsampling will typically produce max_v_samp_factor pixel rows from each |
38 | | * row group (times any additional scale factor that the upsampler is |
39 | | * applying). |
40 | | * |
41 | | * The coefficient controller will deliver data to us one iMCU row at a time; |
42 | | * each iMCU row contains v_samp_factor * DCT_scaled_size sample rows, or |
43 | | * exactly min_DCT_scaled_size row groups. (This amount of data corresponds |
44 | | * to one row of MCUs when the image is fully interleaved.) Note that the |
45 | | * number of sample rows varies across components, but the number of row |
46 | | * groups does not. Some garbage sample rows may be included in the last iMCU |
47 | | * row at the bottom of the image. |
48 | | * |
49 | | * Depending on the vertical scaling algorithm used, the upsampler may need |
50 | | * access to the sample row(s) above and below its current input row group. |
51 | | * The upsampler is required to set need_context_rows TRUE at global selection |
52 | | * time if so. When need_context_rows is FALSE, this controller can simply |
53 | | * obtain one iMCU row at a time from the coefficient controller and dole it |
54 | | * out as row groups to the postprocessor. |
55 | | * |
56 | | * When need_context_rows is TRUE, this controller guarantees that the buffer |
57 | | * passed to postprocessing contains at least one row group's worth of samples |
58 | | * above and below the row group(s) being processed. Note that the context |
59 | | * rows "above" the first passed row group appear at negative row offsets in |
60 | | * the passed buffer. At the top and bottom of the image, the required |
61 | | * context rows are manufactured by duplicating the first or last real sample |
62 | | * row; this avoids having special cases in the upsampling inner loops. |
63 | | * |
64 | | * The amount of context is fixed at one row group just because that's a |
65 | | * convenient number for this controller to work with. The existing |
66 | | * upsamplers really only need one sample row of context. An upsampler |
67 | | * supporting arbitrary output rescaling might wish for more than one row |
68 | | * group of context when shrinking the image; tough, we don't handle that. |
69 | | * (This is justified by the assumption that downsizing will be handled mostly |
70 | | * by adjusting the DCT_scaled_size values, so that the actual scale factor at |
71 | | * the upsample step needn't be much less than one.) |
72 | | * |
73 | | * To provide the desired context, we have to retain the last two row groups |
74 | | * of one iMCU row while reading in the next iMCU row. (The last row group |
75 | | * can't be processed until we have another row group for its below-context, |
76 | | * and so we have to save the next-to-last group too for its above-context.) |
77 | | * We could do this most simply by copying data around in our buffer, but |
78 | | * that'd be very slow. We can avoid copying any data by creating a rather |
79 | | * strange pointer structure. Here's how it works. We allocate a workspace |
80 | | * consisting of M+2 row groups (where M = min_DCT_scaled_size is the number |
81 | | * of row groups per iMCU row). We create two sets of redundant pointers to |
82 | | * the workspace. Labeling the physical row groups 0 to M+1, the synthesized |
83 | | * pointer lists look like this: |
84 | | * M+1 M-1 |
85 | | * master pointer --> 0 master pointer --> 0 |
86 | | * 1 1 |
87 | | * ... ... |
88 | | * M-3 M-3 |
89 | | * M-2 M |
90 | | * M-1 M+1 |
91 | | * M M-2 |
92 | | * M+1 M-1 |
93 | | * 0 0 |
94 | | * We read alternate iMCU rows using each master pointer; thus the last two |
95 | | * row groups of the previous iMCU row remain un-overwritten in the workspace. |
96 | | * The pointer lists are set up so that the required context rows appear to |
97 | | * be adjacent to the proper places when we pass the pointer lists to the |
98 | | * upsampler. |
99 | | * |
100 | | * The above pictures describe the normal state of the pointer lists. |
101 | | * At top and bottom of the image, we diddle the pointer lists to duplicate |
102 | | * the first or last sample row as necessary (this is cheaper than copying |
103 | | * sample rows around). |
104 | | * |
105 | | * This scheme breaks down if M < 2, ie, min_DCT_scaled_size is 1. In that |
106 | | * situation each iMCU row provides only one row group so the buffering logic |
107 | | * must be different (eg, we must read two iMCU rows before we can emit the |
108 | | * first row group). For now, we simply do not support providing context |
109 | | * rows when min_DCT_scaled_size is 1. That combination seems unlikely to |
110 | | * be worth providing --- if someone wants a 1/8th-size preview, they probably |
111 | | * want it quick and dirty, so a context-free upsampler is sufficient. |
112 | | */ |
113 | | |
114 | | |
115 | | /* Forward declarations */ |
116 | | METHODDEF(void) process_data_simple_main(j_decompress_ptr cinfo, |
117 | | JSAMPARRAY output_buf, |
118 | | JDIMENSION *out_row_ctr, |
119 | | JDIMENSION out_rows_avail); |
120 | | METHODDEF(void) process_data_context_main(j_decompress_ptr cinfo, |
121 | | JSAMPARRAY output_buf, |
122 | | JDIMENSION *out_row_ctr, |
123 | | JDIMENSION out_rows_avail); |
124 | | #ifdef QUANT_2PASS_SUPPORTED |
125 | | METHODDEF(void) process_data_crank_post(j_decompress_ptr cinfo, |
126 | | JSAMPARRAY output_buf, |
127 | | JDIMENSION *out_row_ctr, |
128 | | JDIMENSION out_rows_avail); |
129 | | #endif |
130 | | |
131 | | |
132 | | LOCAL(void) |
133 | | alloc_funny_pointers(j_decompress_ptr cinfo) |
134 | | /* Allocate space for the funny pointer lists. |
135 | | * This is done only once, not once per pass. |
136 | | */ |
137 | 19 | { |
138 | 19 | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
139 | 19 | int ci, rgroup; |
140 | 19 | int M = cinfo->_min_DCT_scaled_size; |
141 | 19 | jpeg_component_info *compptr; |
142 | 19 | JSAMPARRAY xbuf; |
143 | | |
144 | | /* Get top-level space for component array pointers. |
145 | | * We alloc both arrays with one call to save a few cycles. |
146 | | */ |
147 | 19 | main_ptr->xbuffer[0] = (JSAMPIMAGE) |
148 | 19 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
149 | 19 | cinfo->num_components * 2 * sizeof(JSAMPARRAY)); |
150 | 19 | main_ptr->xbuffer[1] = main_ptr->xbuffer[0] + cinfo->num_components; |
151 | | |
152 | 76 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
153 | 57 | ci++, compptr++) { |
154 | 57 | rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) / |
155 | 57 | cinfo->_min_DCT_scaled_size; /* height of a row group of component */ |
156 | | /* Get space for pointer lists --- M+4 row groups in each list. |
157 | | * We alloc both pointer lists with one call to save a few cycles. |
158 | | */ |
159 | 57 | xbuf = (JSAMPARRAY) |
160 | 57 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
161 | 57 | 2 * (rgroup * (M + 4)) * sizeof(JSAMPROW)); |
162 | 57 | xbuf += rgroup; /* want one row group at negative offsets */ |
163 | 57 | main_ptr->xbuffer[0][ci] = xbuf; |
164 | 57 | xbuf += rgroup * (M + 4); |
165 | 57 | main_ptr->xbuffer[1][ci] = xbuf; |
166 | 57 | } |
167 | 19 | } |
168 | | |
169 | | |
170 | | LOCAL(void) |
171 | | make_funny_pointers(j_decompress_ptr cinfo) |
172 | | /* Create the funny pointer lists discussed in the comments above. |
173 | | * The actual workspace is already allocated (in main_ptr->buffer), |
174 | | * and the space for the pointer lists is allocated too. |
175 | | * This routine just fills in the curiously ordered lists. |
176 | | * This will be repeated at the beginning of each pass. |
177 | | */ |
178 | 4 | { |
179 | 4 | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
180 | 4 | int ci, i, rgroup; |
181 | 4 | int M = cinfo->_min_DCT_scaled_size; |
182 | 4 | jpeg_component_info *compptr; |
183 | 4 | JSAMPARRAY buf, xbuf0, xbuf1; |
184 | | |
185 | 16 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
186 | 12 | ci++, compptr++) { |
187 | 12 | rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) / |
188 | 12 | cinfo->_min_DCT_scaled_size; /* height of a row group of component */ |
189 | 12 | xbuf0 = main_ptr->xbuffer[0][ci]; |
190 | 12 | xbuf1 = main_ptr->xbuffer[1][ci]; |
191 | | /* First copy the workspace pointers as-is */ |
192 | 12 | buf = main_ptr->buffer[ci]; |
193 | 172 | for (i = 0; i < rgroup * (M + 2); i++) { |
194 | 160 | xbuf0[i] = xbuf1[i] = buf[i]; |
195 | 160 | } |
196 | | /* In the second list, put the last four row groups in swapped order */ |
197 | 44 | for (i = 0; i < rgroup * 2; i++) { |
198 | 32 | xbuf1[rgroup * (M - 2) + i] = buf[rgroup * M + i]; |
199 | 32 | xbuf1[rgroup * M + i] = buf[rgroup * (M - 2) + i]; |
200 | 32 | } |
201 | | /* The wraparound pointers at top and bottom will be filled later |
202 | | * (see set_wraparound_pointers, below). Initially we want the "above" |
203 | | * pointers to duplicate the first actual data line. This only needs |
204 | | * to happen in xbuffer[0]. |
205 | | */ |
206 | 28 | for (i = 0; i < rgroup; i++) { |
207 | 16 | xbuf0[i - rgroup] = xbuf0[0]; |
208 | 16 | } |
209 | 12 | } |
210 | 4 | } |
211 | | |
212 | | |
213 | | LOCAL(void) |
214 | | set_bottom_pointers(j_decompress_ptr cinfo) |
215 | | /* Change the pointer lists to duplicate the last sample row at the bottom |
216 | | * of the image. whichptr indicates which xbuffer holds the final iMCU row. |
217 | | * Also sets rowgroups_avail to indicate number of nondummy row groups in row. |
218 | | */ |
219 | 3 | { |
220 | 3 | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
221 | 3 | int ci, i, rgroup, iMCUheight, rows_left; |
222 | 3 | jpeg_component_info *compptr; |
223 | 3 | JSAMPARRAY xbuf; |
224 | | |
225 | 12 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
226 | 9 | ci++, compptr++) { |
227 | | /* Count sample rows in one iMCU row and in one row group */ |
228 | 9 | iMCUheight = compptr->v_samp_factor * compptr->_DCT_scaled_size; |
229 | 9 | rgroup = iMCUheight / cinfo->_min_DCT_scaled_size; |
230 | | /* Count nondummy sample rows remaining for this component */ |
231 | 9 | rows_left = (int)(compptr->downsampled_height % (JDIMENSION)iMCUheight); |
232 | 9 | if (rows_left == 0) rows_left = iMCUheight; |
233 | | /* Count nondummy row groups. Should get same answer for each component, |
234 | | * so we need only do it once. |
235 | | */ |
236 | 9 | if (ci == 0) { |
237 | 3 | main_ptr->rowgroups_avail = (JDIMENSION)((rows_left - 1) / rgroup + 1); |
238 | 3 | } |
239 | | /* Duplicate the last real sample row rgroup*2 times; this pads out the |
240 | | * last partial rowgroup and ensures at least one full rowgroup of context. |
241 | | */ |
242 | 9 | xbuf = main_ptr->xbuffer[main_ptr->whichptr][ci]; |
243 | 33 | for (i = 0; i < rgroup * 2; i++) { |
244 | 24 | xbuf[rows_left + i] = xbuf[rows_left - 1]; |
245 | 24 | } |
246 | 9 | } |
247 | 3 | } |
248 | | |
249 | | |
250 | | /* |
251 | | * Initialize for a processing pass. |
252 | | */ |
253 | | |
254 | | METHODDEF(void) |
255 | | start_pass_main(j_decompress_ptr cinfo, J_BUF_MODE pass_mode) |
256 | 34 | { |
257 | 34 | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
258 | | |
259 | 34 | switch (pass_mode) { |
260 | 34 | case JBUF_PASS_THRU: |
261 | 34 | if (cinfo->upsample->need_context_rows) { |
262 | 4 | main_ptr->pub.process_data = process_data_context_main; |
263 | 4 | make_funny_pointers(cinfo); /* Create the xbuffer[] lists */ |
264 | 4 | main_ptr->whichptr = 0; /* Read first iMCU row into xbuffer[0] */ |
265 | 4 | main_ptr->context_state = CTX_PREPARE_FOR_IMCU; |
266 | 4 | main_ptr->iMCU_row_ctr = 0; |
267 | 30 | } else { |
268 | | /* Simple case with no context needed */ |
269 | 30 | main_ptr->pub.process_data = process_data_simple_main; |
270 | 30 | } |
271 | 34 | main_ptr->buffer_full = FALSE; /* Mark buffer empty */ |
272 | 34 | main_ptr->rowgroup_ctr = 0; |
273 | 34 | break; |
274 | 0 | #ifdef QUANT_2PASS_SUPPORTED |
275 | 0 | case JBUF_CRANK_DEST: |
276 | | /* For last pass of 2-pass quantization, just crank the postprocessor */ |
277 | 0 | main_ptr->pub.process_data = process_data_crank_post; |
278 | 0 | break; |
279 | 0 | #endif |
280 | 0 | default: |
281 | 0 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
282 | 0 | break; |
283 | 34 | } |
284 | 34 | } |
285 | | |
286 | | |
287 | | /* |
288 | | * Process some data. |
289 | | * This handles the simple case where no context is required. |
290 | | */ |
291 | | |
292 | | METHODDEF(void) |
293 | | process_data_simple_main(j_decompress_ptr cinfo, JSAMPARRAY output_buf, |
294 | | JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
295 | 73.7k | { |
296 | 73.7k | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
297 | 73.7k | JDIMENSION rowgroups_avail; |
298 | | |
299 | | /* Read input data if we haven't filled the main buffer yet */ |
300 | 73.7k | if (!main_ptr->buffer_full) { |
301 | 8.78k | if (!(*cinfo->coef->decompress_data) (cinfo, main_ptr->buffer)) |
302 | 10 | return; /* suspension forced, can do nothing more */ |
303 | 8.77k | main_ptr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */ |
304 | 8.77k | } |
305 | | |
306 | | /* There are always min_DCT_scaled_size row groups in an iMCU row. */ |
307 | 73.7k | rowgroups_avail = (JDIMENSION)cinfo->_min_DCT_scaled_size; |
308 | | /* Note: at the bottom of the image, we may pass extra garbage row groups |
309 | | * to the postprocessor. The postprocessor has to check for bottom |
310 | | * of image anyway (at row resolution), so no point in us doing it too. |
311 | | */ |
312 | | |
313 | | /* Feed the postprocessor */ |
314 | 73.7k | (*cinfo->post->post_process_data) (cinfo, main_ptr->buffer, |
315 | 73.7k | &main_ptr->rowgroup_ctr, rowgroups_avail, |
316 | 73.7k | output_buf, out_row_ctr, out_rows_avail); |
317 | | |
318 | | /* Has postprocessor consumed all the data yet? If so, mark buffer empty */ |
319 | 73.7k | if (main_ptr->rowgroup_ctr >= rowgroups_avail) { |
320 | 8.76k | main_ptr->buffer_full = FALSE; |
321 | 8.76k | main_ptr->rowgroup_ctr = 0; |
322 | 8.76k | } |
323 | 73.7k | } |
324 | | |
325 | | |
326 | | /* |
327 | | * Process some data. |
328 | | * This handles the case where context rows must be provided. |
329 | | */ |
330 | | |
331 | | METHODDEF(void) |
332 | | process_data_context_main(j_decompress_ptr cinfo, JSAMPARRAY output_buf, |
333 | | JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
334 | 10.9k | { |
335 | 10.9k | my_main_ptr main_ptr = (my_main_ptr)cinfo->main; |
336 | | |
337 | | /* Read input data if we haven't filled the main buffer yet */ |
338 | 10.9k | if (!main_ptr->buffer_full) { |
339 | 687 | if (!(*cinfo->coef->decompress_data) (cinfo, |
340 | 687 | main_ptr->xbuffer[main_ptr->whichptr])) |
341 | 1 | return; /* suspension forced, can do nothing more */ |
342 | 686 | main_ptr->buffer_full = TRUE; /* OK, we have an iMCU row to work with */ |
343 | 686 | main_ptr->iMCU_row_ctr++; /* count rows received */ |
344 | 686 | } |
345 | | |
346 | | /* Postprocessor typically will not swallow all the input data it is handed |
347 | | * in one call (due to filling the output buffer first). Must be prepared |
348 | | * to exit and restart. This switch lets us keep track of how far we got. |
349 | | * Note that each case falls through to the next on successful completion. |
350 | | */ |
351 | 10.9k | switch (main_ptr->context_state) { |
352 | 1.36k | case CTX_POSTPONED_ROW: |
353 | | /* Call postprocessor using previously set pointers for postponed row */ |
354 | 1.36k | (*cinfo->post->post_process_data) (cinfo, |
355 | 1.36k | main_ptr->xbuffer[main_ptr->whichptr], |
356 | 1.36k | &main_ptr->rowgroup_ctr, |
357 | 1.36k | main_ptr->rowgroups_avail, output_buf, |
358 | 1.36k | out_row_ctr, out_rows_avail); |
359 | 1.36k | if (main_ptr->rowgroup_ctr < main_ptr->rowgroups_avail) |
360 | 682 | return; /* Need to suspend */ |
361 | 682 | main_ptr->context_state = CTX_PREPARE_FOR_IMCU; |
362 | 682 | if (*out_row_ctr >= out_rows_avail) |
363 | 682 | return; /* Postprocessor exactly filled output buf */ |
364 | | FALLTHROUGH /*FALLTHROUGH*/ |
365 | 686 | case CTX_PREPARE_FOR_IMCU: |
366 | | /* Prepare to process first M-1 row groups of this iMCU row */ |
367 | 686 | main_ptr->rowgroup_ctr = 0; |
368 | 686 | main_ptr->rowgroups_avail = (JDIMENSION)(cinfo->_min_DCT_scaled_size - 1); |
369 | | /* Check for bottom of image: if so, tweak pointers to "duplicate" |
370 | | * the last sample row, and adjust rowgroups_avail to ignore padding rows. |
371 | | */ |
372 | 686 | if (main_ptr->iMCU_row_ctr == cinfo->total_iMCU_rows) |
373 | 3 | set_bottom_pointers(cinfo); |
374 | 686 | main_ptr->context_state = CTX_PROCESS_IMCU; |
375 | | FALLTHROUGH /*FALLTHROUGH*/ |
376 | 9.61k | case CTX_PROCESS_IMCU: |
377 | | /* Call postprocessor using previously set pointers */ |
378 | 9.61k | (*cinfo->post->post_process_data) (cinfo, |
379 | 9.61k | main_ptr->xbuffer[main_ptr->whichptr], |
380 | 9.61k | &main_ptr->rowgroup_ctr, |
381 | 9.61k | main_ptr->rowgroups_avail, output_buf, |
382 | 9.61k | out_row_ctr, out_rows_avail); |
383 | 9.61k | if (main_ptr->rowgroup_ctr < main_ptr->rowgroups_avail) |
384 | 8.92k | return; /* Need to suspend */ |
385 | | /* After the first iMCU, change wraparound pointers to normal state */ |
386 | 686 | if (main_ptr->iMCU_row_ctr == 1) |
387 | 4 | set_wraparound_pointers(cinfo); |
388 | | /* Prepare to load new iMCU row using other xbuffer list */ |
389 | 686 | main_ptr->whichptr ^= 1; /* 0=>1 or 1=>0 */ |
390 | 686 | main_ptr->buffer_full = FALSE; |
391 | | /* Still need to process last row group of this iMCU row, */ |
392 | | /* which is saved at index M+1 of the other xbuffer */ |
393 | 686 | main_ptr->rowgroup_ctr = (JDIMENSION)(cinfo->_min_DCT_scaled_size + 1); |
394 | 686 | main_ptr->rowgroups_avail = (JDIMENSION)(cinfo->_min_DCT_scaled_size + 2); |
395 | 686 | main_ptr->context_state = CTX_POSTPONED_ROW; |
396 | 10.9k | } |
397 | 10.9k | } |
398 | | |
399 | | |
400 | | /* |
401 | | * Process some data. |
402 | | * Final pass of two-pass quantization: just call the postprocessor. |
403 | | * Source data will be the postprocessor controller's internal buffer. |
404 | | */ |
405 | | |
406 | | #ifdef QUANT_2PASS_SUPPORTED |
407 | | |
408 | | METHODDEF(void) |
409 | | process_data_crank_post(j_decompress_ptr cinfo, JSAMPARRAY output_buf, |
410 | | JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail) |
411 | 0 | { |
412 | 0 | (*cinfo->post->post_process_data) (cinfo, (JSAMPIMAGE)NULL, |
413 | 0 | (JDIMENSION *)NULL, (JDIMENSION)0, |
414 | 0 | output_buf, out_row_ctr, out_rows_avail); |
415 | 0 | } |
416 | | |
417 | | #endif /* QUANT_2PASS_SUPPORTED */ |
418 | | |
419 | | |
420 | | /* |
421 | | * Initialize main buffer controller. |
422 | | */ |
423 | | |
424 | | GLOBAL(void) |
425 | | jinit_d_main_controller(j_decompress_ptr cinfo, boolean need_full_buffer) |
426 | 124 | { |
427 | 124 | my_main_ptr main_ptr; |
428 | 124 | int ci, rgroup, ngroups; |
429 | 124 | jpeg_component_info *compptr; |
430 | | |
431 | 124 | main_ptr = (my_main_ptr) |
432 | 124 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
433 | 124 | sizeof(my_main_controller)); |
434 | 124 | cinfo->main = (struct jpeg_d_main_controller *)main_ptr; |
435 | 124 | main_ptr->pub.start_pass = start_pass_main; |
436 | | |
437 | 124 | if (need_full_buffer) /* shouldn't happen */ |
438 | 0 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
439 | | |
440 | | /* Allocate the workspace. |
441 | | * ngroups is the number of row groups we need. |
442 | | */ |
443 | 124 | if (cinfo->upsample->need_context_rows) { |
444 | 19 | if (cinfo->_min_DCT_scaled_size < 2) /* unsupported, see comments above */ |
445 | 0 | ERREXIT(cinfo, JERR_NOTIMPL); |
446 | 19 | alloc_funny_pointers(cinfo); /* Alloc space for xbuffer[] lists */ |
447 | 19 | ngroups = cinfo->_min_DCT_scaled_size + 2; |
448 | 105 | } else { |
449 | 105 | ngroups = cinfo->_min_DCT_scaled_size; |
450 | 105 | } |
451 | | |
452 | 459 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
453 | 335 | ci++, compptr++) { |
454 | 335 | rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) / |
455 | 335 | cinfo->_min_DCT_scaled_size; /* height of a row group of component */ |
456 | 335 | main_ptr->buffer[ci] = (*cinfo->mem->alloc_sarray) |
457 | 335 | ((j_common_ptr)cinfo, JPOOL_IMAGE, |
458 | 335 | compptr->width_in_blocks * compptr->_DCT_scaled_size, |
459 | 335 | (JDIMENSION)(rgroup * ngroups)); |
460 | 335 | } |
461 | 124 | } |