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1 /*
2  * This file is part of the PulseView project.
3  *
4  * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19
20 #include "config.h" // For HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
21
22 #include <extdef.h>
23
24 #include <cassert>
25 #include <cmath>
26 #include <cstdlib>
27 #include <cstring>
28 #include <cstdint>
29
30 #include "logic.hpp"
31 #include "logicsegment.hpp"
32
33 #include <libsigrokcxx/libsigrokcxx.hpp>
34
35 using std::lock_guard;
36 using std::recursive_mutex;
37 using std::max;
38 using std::min;
39 using std::shared_ptr;
40 using std::vector;
41
42 using sigrok::Logic;
43
44 namespace pv {
45 namespace data {
46
47 const int LogicSegment::MipMapScalePower = 4;
48 const int LogicSegment::MipMapScaleFactor = 1 << MipMapScalePower;
49 const float LogicSegment::LogMipMapScaleFactor = logf(MipMapScaleFactor);
50 const uint64_t LogicSegment::MipMapDataUnit = 64 * 1024; // bytes
51
52 LogicSegment::LogicSegment(pv::data::Logic& owner, uint32_t segment_id,
53         unsigned int unit_size, uint64_t samplerate) :
54         Segment(segment_id, samplerate, unit_size),
55         owner_(owner),
56         last_append_sample_(0),
57         last_append_accumulator_(0),
58         last_append_extra_(0)
59 {
60         memset(mip_map_, 0, sizeof(mip_map_));
61 }
62
63 LogicSegment::~LogicSegment()
64 {
65         lock_guard<recursive_mutex> lock(mutex_);
66
67         for (MipMapLevel &l : mip_map_)
68                 free(l.data);
69 }
70
71 shared_ptr<const LogicSegment> LogicSegment::get_shared_ptr() const
72 {
73         shared_ptr<const Segment> ptr = nullptr;
74
75         try {
76                 ptr = shared_from_this();
77         } catch (std::exception& e) {
78                 /* Do nothing, ptr remains a null pointer */
79         }
80
81         return ptr ? std::dynamic_pointer_cast<const LogicSegment>(ptr) : nullptr;
82 }
83
84 template <class T>
85 void LogicSegment::downsampleTmain(const T*&in, T &acc, T &prev)
86 {
87         // Accumulate one sample at a time
88         for (uint64_t i = 0; i < MipMapScaleFactor; i++) {
89                 T sample = *in++;
90                 acc |= prev ^ sample;
91                 prev = sample;
92         }
93 }
94
95 template <>
96 void LogicSegment::downsampleTmain<uint8_t>(const uint8_t*&in, uint8_t &acc, uint8_t &prev)
97 {
98         // Handle 8 bit samples in 32 bit steps
99         uint32_t prev32 = prev | prev << 8 | prev << 16 | prev << 24;
100         uint32_t acc32 = acc;
101         const uint32_t *in32 = (const uint32_t*)in;
102         for (uint64_t i = 0; i < MipMapScaleFactor; i += 4) {
103                 uint32_t sample32 = *in32++;
104                 acc32 |= prev32 ^ sample32;
105                 prev32 = sample32;
106         }
107         // Reduce result back to uint8_t
108 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
109         prev = (prev32 >> 24) & 0xff; // MSB is last
110 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
111         prev = prev32 & 0xff; // LSB is last
112 #else
113 #error Endianness unknown
114 #endif
115         acc |= acc32 & 0xff;
116         acc |= (acc32 >> 8) & 0xff;
117         acc |= (acc32 >> 16) & 0xff;
118         acc |= (acc32 >> 24) & 0xff;
119         in = (const uint8_t*)in32;
120 }
121
122 template <>
123 void LogicSegment::downsampleTmain<uint16_t>(const uint16_t*&in, uint16_t &acc, uint16_t &prev)
124 {
125         // Handle 16 bit samples in 32 bit steps
126         uint32_t prev32 = prev | prev << 16;
127         uint32_t acc32 = acc;
128         const uint32_t *in32 = (const uint32_t*)in;
129         for (uint64_t i = 0; i < MipMapScaleFactor; i += 2) {
130                 uint32_t sample32 = *in32++;
131                 acc32 |= prev32 ^ sample32;
132                 prev32 = sample32;
133         }
134         // Reduce result back to uint16_t
135 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
136         prev = (prev32 >> 16) & 0xffff; // MSB is last
137 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
138         prev = prev32 & 0xffff; // LSB is last
139 #else
140 #error Endian unknown
141 #endif
142         acc |= acc32 & 0xffff;
143         acc |= (acc32 >> 16) & 0xffff;
144         in = (const uint16_t*)in32;
145 }
146
147 template <class T>
148 void LogicSegment::downsampleT(const uint8_t *in_, uint8_t *&out_, uint64_t len)
149 {
150         const T *in = (const T*)in_;
151         T *out = (T*)out_;
152         T prev = last_append_sample_;
153         T acc = last_append_accumulator_;
154
155         // Try to complete the previous downsample
156         if (last_append_extra_) {
157                 while (last_append_extra_ < MipMapScaleFactor && len > 0) {
158                         T sample = *in++;
159                         acc |= prev ^ sample;
160                         prev = sample;
161                         last_append_extra_++;
162                         len--;
163                 }
164                 if (!len) {
165                         // Not enough samples available to complete downsample
166                         last_append_sample_ = prev;
167                         last_append_accumulator_ = acc;
168                         return;
169                 }
170                 // We have a complete downsample
171                 *out++ = acc;
172                 acc = 0;
173                 last_append_extra_ = 0;
174         }
175
176         // Handle complete blocks of MipMapScaleFactor samples
177         while (len >= MipMapScaleFactor) {
178                 downsampleTmain<T>(in, acc, prev);
179                 len -= MipMapScaleFactor;
180                 // Output downsample
181                 *out++ = acc;
182                 acc = 0;
183         }
184
185         // Process remainder, not enough for a complete sample
186         while (len > 0) {
187                 T sample = *in++;
188                 acc |= prev ^ sample;
189                 prev = sample;
190                 last_append_extra_++;
191                 len--;
192         }
193
194         // Update context
195         last_append_sample_ = prev;
196         last_append_accumulator_ = acc;
197         out_ = (uint8_t *)out;
198 }
199
200 void LogicSegment::downsampleGeneric(const uint8_t *in, uint8_t *&out, uint64_t len)
201 {
202         // Downsample using the generic unpack_sample()
203         // which can handle any width between 1 and 8 bytes
204         uint64_t prev = last_append_sample_;
205         uint64_t acc = last_append_accumulator_;
206
207         // Try to complete the previous downsample
208         if (last_append_extra_) {
209                 while (last_append_extra_ < MipMapScaleFactor && len > 0) {
210                         const uint64_t sample = unpack_sample(in);
211                         in += unit_size_;
212                         acc |= prev ^ sample;
213                         prev = sample;
214                         last_append_extra_++;
215                         len--;
216                 }
217                 if (!len) {
218                         // Not enough samples available to complete downsample
219                         last_append_sample_ = prev;
220                         last_append_accumulator_ = acc;
221                         return;
222                 }
223                 // We have a complete downsample
224                 pack_sample(out, acc);
225                 out += unit_size_;
226                 acc = 0;
227                 last_append_extra_ = 0;
228         }
229
230         // Handle complete blocks of MipMapScaleFactor samples
231         while (len >= MipMapScaleFactor) {
232                 // Accumulate one sample at a time
233                 for (uint64_t i = 0; i < MipMapScaleFactor; i++) {
234                         const uint64_t sample = unpack_sample(in);
235                         in += unit_size_;
236                         acc |= prev ^ sample;
237                         prev = sample;
238                 }
239                 len -= MipMapScaleFactor;
240                 // Output downsample
241                 pack_sample(out, acc);
242                 out += unit_size_;
243                 acc = 0;
244         }
245
246         // Process remainder, not enough for a complete sample
247         while (len > 0) {
248                 const uint64_t sample = unpack_sample(in);
249                 in += unit_size_;
250                 acc |= prev ^ sample;
251                 prev = sample;
252                 last_append_extra_++;
253                 len--;
254         }
255
256         // Update context
257         last_append_sample_ = prev;
258         last_append_accumulator_ = acc;
259 }
260
261 inline uint64_t LogicSegment::unpack_sample(const uint8_t *ptr) const
262 {
263 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
264         return *(uint64_t*)ptr;
265 #else
266         uint64_t value = 0;
267         switch (unit_size_) {
268         default:
269                 value |= ((uint64_t)ptr[7]) << 56;
270                 /* FALLTHRU */
271         case 7:
272                 value |= ((uint64_t)ptr[6]) << 48;
273                 /* FALLTHRU */
274         case 6:
275                 value |= ((uint64_t)ptr[5]) << 40;
276                 /* FALLTHRU */
277         case 5:
278                 value |= ((uint64_t)ptr[4]) << 32;
279                 /* FALLTHRU */
280         case 4:
281                 value |= ((uint32_t)ptr[3]) << 24;
282                 /* FALLTHRU */
283         case 3:
284                 value |= ((uint32_t)ptr[2]) << 16;
285                 /* FALLTHRU */
286         case 2:
287                 value |= ptr[1] << 8;
288                 /* FALLTHRU */
289         case 1:
290                 value |= ptr[0];
291                 /* FALLTHRU */
292         case 0:
293                 break;
294         }
295         return value;
296 #endif
297 }
298
299 inline void LogicSegment::pack_sample(uint8_t *ptr, uint64_t value)
300 {
301 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
302         *(uint64_t*)ptr = value;
303 #else
304         switch (unit_size_) {
305         default:
306                 ptr[7] = value >> 56;
307                 /* FALLTHRU */
308         case 7:
309                 ptr[6] = value >> 48;
310                 /* FALLTHRU */
311         case 6:
312                 ptr[5] = value >> 40;
313                 /* FALLTHRU */
314         case 5:
315                 ptr[4] = value >> 32;
316                 /* FALLTHRU */
317         case 4:
318                 ptr[3] = value >> 24;
319                 /* FALLTHRU */
320         case 3:
321                 ptr[2] = value >> 16;
322                 /* FALLTHRU */
323         case 2:
324                 ptr[1] = value >> 8;
325                 /* FALLTHRU */
326         case 1:
327                 ptr[0] = value;
328                 /* FALLTHRU */
329         case 0:
330                 break;
331         }
332 #endif
333 }
334
335 void LogicSegment::append_payload(shared_ptr<sigrok::Logic> logic)
336 {
337         assert(unit_size_ == logic->unit_size());
338         assert((logic->data_length() % unit_size_) == 0);
339
340         append_payload(logic->data_pointer(), logic->data_length());
341 }
342
343 void LogicSegment::append_payload(void *data, uint64_t data_size)
344 {
345         assert(unit_size_ > 0);
346         assert((data_size % unit_size_) == 0);
347
348         lock_guard<recursive_mutex> lock(mutex_);
349
350         const uint64_t prev_sample_count = sample_count_;
351         const uint64_t sample_count = data_size / unit_size_;
352
353         append_samples(data, sample_count);
354
355         // Generate the first mip-map from the data
356         append_payload_to_mipmap();
357
358         if (sample_count > 1)
359                 owner_.notify_samples_added(SharedPtrToSegment(shared_from_this()),
360                         prev_sample_count + 1, prev_sample_count + 1 + sample_count);
361         else
362                 owner_.notify_samples_added(SharedPtrToSegment(shared_from_this()),
363                         prev_sample_count + 1, prev_sample_count + 1);
364 }
365
366 void LogicSegment::append_subsignal_payload(unsigned int index, void *data,
367         uint64_t data_size, vector<uint8_t>& destination)
368 {
369         if (index == 0)
370                 destination.resize(data_size * unit_size_, 0);
371
372         // Set the bits for this sub-signal where needed
373         // Note: the bytes in *data must either be 0 or 1, nothing else
374         unsigned int index_byte_offs = index / 8;
375         uint8_t* output_data = destination.data() + index_byte_offs;
376         uint8_t* input_data = (uint8_t*)data;
377
378         for (uint64_t i = 0; i < data_size; i++) {
379                 assert((i * unit_size_ + index_byte_offs) < destination.size());
380                 *output_data |= (input_data[i] << index);
381                 output_data += unit_size_;
382         }
383
384         if (index == owner_.num_channels() - 1) {
385                 // We gathered sample data of all sub-signals, let's append it
386                 append_payload(destination.data(), destination.size());
387                 destination.clear();
388         }
389 }
390
391 void LogicSegment::get_samples(int64_t start_sample,
392         int64_t end_sample, uint8_t* dest) const
393 {
394         assert(start_sample >= 0);
395         assert(start_sample <= (int64_t)sample_count_);
396         assert(end_sample >= 0);
397         assert(end_sample <= (int64_t)sample_count_);
398         assert(start_sample <= end_sample);
399         assert(dest != nullptr);
400
401         lock_guard<recursive_mutex> lock(mutex_);
402
403         get_raw_samples(start_sample, (end_sample - start_sample), dest);
404 }
405
406 void LogicSegment::get_subsampled_edges(
407         vector<EdgePair> &edges,
408         uint64_t start, uint64_t end,
409         float min_length, int sig_index, bool first_change_only)
410 {
411         uint64_t index = start;
412         unsigned int level;
413         bool last_sample;
414         bool fast_forward;
415
416         assert(start <= end);
417         assert(min_length > 0);
418         assert(sig_index >= 0);
419         assert(sig_index < 64);
420
421         lock_guard<recursive_mutex> lock(mutex_);
422
423         // Make sure we only process as many samples as we have
424         if (end > get_sample_count())
425                 end = get_sample_count();
426
427         const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
428         const unsigned int min_level = max((int)floorf(logf(min_length) /
429                 LogMipMapScaleFactor) - 1, 0);
430         const uint64_t sig_mask = 1ULL << sig_index;
431
432         // Store the initial state
433         last_sample = (get_unpacked_sample(start) & sig_mask) != 0;
434         if (!first_change_only)
435                 edges.emplace_back(index++, last_sample);
436
437         while (index + block_length <= end) {
438                 //----- Continue to search -----//
439                 level = min_level;
440
441                 // We cannot fast-forward if there is no mip-map data at
442                 // the minimum level.
443                 fast_forward = (mip_map_[level].data != nullptr);
444
445                 if (min_length < MipMapScaleFactor) {
446                         // Search individual samples up to the beginning of
447                         // the next first level mip map block
448                         const uint64_t final_index = min(end, pow2_ceil(index, MipMapScalePower));
449
450                         for (; index < final_index &&
451                                         (index & ~((uint64_t)(~0) << MipMapScalePower)) != 0;
452                                         index++) {
453
454                                 const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
455
456                                 // If there was a change we cannot fast forward
457                                 if (sample != last_sample) {
458                                         fast_forward = false;
459                                         break;
460                                 }
461                         }
462                 } else {
463                         // If resolution is less than a mip map block,
464                         // round up to the beginning of the mip-map block
465                         // for this level of detail
466                         const int min_level_scale_power = (level + 1) * MipMapScalePower;
467                         index = pow2_ceil(index, min_level_scale_power);
468                         if (index >= end)
469                                 break;
470
471                         // We can fast forward only if there was no change
472                         const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
473                         if (last_sample != sample)
474                                 fast_forward = false;
475                 }
476
477                 if (fast_forward) {
478
479                         // Fast forward: This involves zooming out to higher
480                         // levels of the mip map searching for changes, then
481                         // zooming in on them to find the point where the edge
482                         // begins.
483
484                         // Slide right and zoom out at the beginnings of mip-map
485                         // blocks until we encounter a change
486                         while (true) {
487                                 const int level_scale_power = (level + 1) * MipMapScalePower;
488                                 const uint64_t offset = index >> level_scale_power;
489
490                                 // Check if we reached the last block at this
491                                 // level, or if there was a change in this block
492                                 if (offset >= mip_map_[level].length ||
493                                         (get_subsample(level, offset) & sig_mask))
494                                         break;
495
496                                 if ((offset & ~((uint64_t)(~0) << MipMapScalePower)) == 0) {
497                                         // If we are now at the beginning of a
498                                         // higher level mip-map block ascend one
499                                         // level
500                                         if ((level + 1 >= ScaleStepCount) || (!mip_map_[level + 1].data))
501                                                 break;
502
503                                         level++;
504                                 } else {
505                                         // Slide right to the beginning of the
506                                         // next mip map block
507                                         index = pow2_ceil(index + 1, level_scale_power);
508                                 }
509                         }
510
511                         // Zoom in, and slide right until we encounter a change,
512                         // and repeat until we reach min_level
513                         while (true) {
514                                 assert(mip_map_[level].data);
515
516                                 const int level_scale_power = (level + 1) * MipMapScalePower;
517                                 const uint64_t offset = index >> level_scale_power;
518
519                                 // Check if we reached the last block at this
520                                 // level, or if there was a change in this block
521                                 if (offset >= mip_map_[level].length ||
522                                                 (get_subsample(level, offset) & sig_mask)) {
523                                         // Zoom in unless we reached the minimum
524                                         // zoom
525                                         if (level == min_level)
526                                                 break;
527
528                                         level--;
529                                 } else {
530                                         // Slide right to the beginning of the
531                                         // next mip map block
532                                         index = pow2_ceil(index + 1, level_scale_power);
533                                 }
534                         }
535
536                         // If individual samples within the limit of resolution,
537                         // do a linear search for the next transition within the
538                         // block
539                         if (min_length < MipMapScaleFactor) {
540                                 for (; index < end; index++) {
541                                         const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
542                                         if (sample != last_sample)
543                                                 break;
544                                 }
545                         }
546                 }
547
548                 //----- Store the edge -----//
549
550                 // Take the last sample of the quanization block
551                 const int64_t final_index = index + block_length;
552                 if (index + block_length > end)
553                         break;
554
555                 // Store the final state
556                 const bool final_sample = (get_unpacked_sample(final_index - 1) & sig_mask) != 0;
557                 edges.emplace_back(index, final_sample);
558
559                 index = final_index;
560                 last_sample = final_sample;
561
562                 if (first_change_only)
563                         break;
564         }
565
566         // Add the final state
567         if (!first_change_only) {
568                 const bool end_sample = get_unpacked_sample(end) & sig_mask;
569                 if (last_sample != end_sample)
570                         edges.emplace_back(end, end_sample);
571                 edges.emplace_back(end + 1, end_sample);
572         }
573 }
574
575 void LogicSegment::get_surrounding_edges(vector<EdgePair> &dest,
576         uint64_t origin_sample, float min_length, int sig_index)
577 {
578         if (origin_sample >= sample_count_)
579                 return;
580
581         // Put the edges vector on the heap, it can become quite big until we can
582         // use a get_subsampled_edges() implementation that searches backwards
583         vector<EdgePair>* edges = new vector<EdgePair>;
584
585         // Get all edges to the left of origin_sample
586         get_subsampled_edges(*edges, 0, origin_sample, min_length, sig_index, false);
587
588         // If we don't specify "first only", the first and last edge are the states
589         // at samples 0 and origin_sample. If only those exist, there are no edges
590         if (edges->size() == 2) {
591                 delete edges;
592                 return;
593         }
594
595         // Dismiss the entry for origin_sample so that back() gives us the
596         // real last entry
597         edges->pop_back();
598         dest.push_back(edges->back());
599         edges->clear();
600
601         // Get first edge to the right of origin_sample
602         get_subsampled_edges(*edges, origin_sample, sample_count_, min_length, sig_index, true);
603
604         // "first only" is specified, so nothing needs to be dismissed
605         if (edges->size() == 0) {
606                 delete edges;
607                 return;
608         }
609
610         dest.push_back(edges->front());
611
612         delete edges;
613 }
614
615 void LogicSegment::reallocate_mipmap_level(MipMapLevel &m)
616 {
617         lock_guard<recursive_mutex> lock(mutex_);
618
619         const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
620                 MipMapDataUnit) * MipMapDataUnit;
621
622         if (new_data_length > m.data_length) {
623                 m.data_length = new_data_length;
624
625                 // Padding is added to allow for the uint64_t write word
626                 m.data = realloc(m.data, new_data_length * unit_size_ +
627                         sizeof(uint64_t));
628         }
629 }
630
631 void LogicSegment::append_payload_to_mipmap()
632 {
633         MipMapLevel &m0 = mip_map_[0];
634         uint64_t prev_length;
635         uint8_t *dest_ptr;
636         SegmentDataIterator* it;
637         uint64_t accumulator;
638         unsigned int diff_counter;
639
640         // Expand the data buffer to fit the new samples
641         prev_length = m0.length;
642         m0.length = sample_count_ / MipMapScaleFactor;
643
644         // Break off if there are no new samples to compute
645         if (m0.length == prev_length)
646                 return;
647
648         reallocate_mipmap_level(m0);
649
650         dest_ptr = (uint8_t*)m0.data + prev_length * unit_size_;
651
652         // Iterate through the samples to populate the first level mipmap
653         const uint64_t start_sample = prev_length * MipMapScaleFactor;
654         const uint64_t end_sample = m0.length * MipMapScaleFactor;
655         uint64_t len_sample = end_sample - start_sample;
656         it = begin_sample_iteration(start_sample);
657         while (len_sample > 0) {
658                 // Number of samples available in this chunk
659                 uint64_t count = get_iterator_valid_length(it);
660                 // Reduce if less than asked for
661                 count = std::min(count, len_sample);
662                 uint8_t *src_ptr = get_iterator_value(it);
663                 // Submit these contiguous samples to downsampling in bulk
664                 if (unit_size_ == 1)
665                         downsampleT<uint8_t>(src_ptr, dest_ptr, count);
666                 else if (unit_size_ == 2)
667                         downsampleT<uint16_t>(src_ptr, dest_ptr, count);
668                 else if (unit_size_ == 4)
669                         downsampleT<uint32_t>(src_ptr, dest_ptr, count);
670                 else if (unit_size_ == 8)
671                         downsampleT<uint64_t>(src_ptr, dest_ptr, count);
672                 else
673                         downsampleGeneric(src_ptr, dest_ptr, count);
674                 len_sample -= count;
675                 // Advance iterator, should move to start of next chunk
676                 continue_sample_iteration(it, count);
677         }
678         end_sample_iteration(it);
679
680         // Compute higher level mipmaps
681         for (unsigned int level = 1; level < ScaleStepCount; level++) {
682                 MipMapLevel &m = mip_map_[level];
683                 const MipMapLevel &ml = mip_map_[level - 1];
684
685                 // Expand the data buffer to fit the new samples
686                 prev_length = m.length;
687                 m.length = ml.length / MipMapScaleFactor;
688
689                 // Break off if there are no more samples to be computed
690                 if (m.length == prev_length)
691                         break;
692
693                 reallocate_mipmap_level(m);
694
695                 // Subsample the lower level
696                 const uint8_t* src_ptr = (uint8_t*)ml.data +
697                         unit_size_ * prev_length * MipMapScaleFactor;
698                 const uint8_t *const end_dest_ptr =
699                         (uint8_t*)m.data + unit_size_ * m.length;
700
701                 for (dest_ptr = (uint8_t*)m.data +
702                                 unit_size_ * prev_length;
703                                 dest_ptr < end_dest_ptr;
704                                 dest_ptr += unit_size_) {
705                         accumulator = 0;
706                         diff_counter = MipMapScaleFactor;
707                         while (diff_counter-- > 0) {
708                                 accumulator |= unpack_sample(src_ptr);
709                                 src_ptr += unit_size_;
710                         }
711
712                         pack_sample(dest_ptr, accumulator);
713                 }
714         }
715 }
716
717 uint64_t LogicSegment::get_unpacked_sample(uint64_t index) const
718 {
719         assert(index < sample_count_);
720
721         assert(unit_size_ <= 8);  // 8 * 8 = 64 channels
722         uint8_t data[8];
723
724         get_raw_samples(index, 1, data);
725
726         return unpack_sample(data);
727 }
728
729 uint64_t LogicSegment::get_subsample(int level, uint64_t offset) const
730 {
731         assert(level >= 0);
732         assert(mip_map_[level].data);
733         return unpack_sample((uint8_t*)mip_map_[level].data +
734                 unit_size_ * offset);
735 }
736
737 uint64_t LogicSegment::pow2_ceil(uint64_t x, unsigned int power)
738 {
739         const uint64_t p = UINT64_C(1) << power;
740         return (x + p - 1) / p * p;
741 }
742
743 } // namespace data
744 } // namespace pv