pv/data/logicsegment.cpp

   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 <extdef.h>
  21
  22 #include <assert.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <cmath>
  26
  27 #include "logicsegment.hpp"
  28
  29 #include <libsigrokcxx/libsigrokcxx.hpp>
  30
  31 using std::lock_guard;
  32 using std::recursive_mutex;
  33 using std::max;
  34 using std::min;
  35 using std::pair;
  36 using std::shared_ptr;
  37
  38 using sigrok::Logic;
  39
  40 namespace pv {
  41 namespace data {
  42
  43 const int LogicSegment::MipMapScalePower = 4;
  44 const int LogicSegment::MipMapScaleFactor = 1 << MipMapScalePower;
  45 const float LogicSegment::LogMipMapScaleFactor = logf(MipMapScaleFactor);
  46 const uint64_t LogicSegment::MipMapDataUnit = 64*1024;  // bytes
  47
  48 LogicSegment::LogicSegment(shared_ptr<Logic> logic, uint64_t samplerate,
  49                                 const uint64_t expected_num_samples) :
  50         Segment(samplerate, logic->unit_size()),
  51         last_append_sample_(0)
  52 {
  53         set_capacity(expected_num_samples);
  54
  55         lock_guard<recursive_mutex> lock(mutex_);
  56         memset(mip_map_, 0, sizeof(mip_map_));
  57         append_payload(logic);
  58 }
  59
  60 LogicSegment::~LogicSegment()
  61 {
  62         lock_guard<recursive_mutex> lock(mutex_);
  63         for (MipMapLevel &l : mip_map_)
  64                 free(l.data);
  65 }
  66
  67 uint64_t LogicSegment::unpack_sample(const uint8_t *ptr) const
  68 {
  69 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
  70         return *(uint64_t*)ptr;
  71 #else
  72         uint64_t value = 0;
  73         switch (unit_size_) {
  74         default:
  75                 value |= ((uint64_t)ptr[7]) << 56;
  76                 /* FALLTHRU */
  77         case 7:
  78                 value |= ((uint64_t)ptr[6]) << 48;
  79                 /* FALLTHRU */
  80         case 6:
  81                 value |= ((uint64_t)ptr[5]) << 40;
  82                 /* FALLTHRU */
  83         case 5:
  84                 value |= ((uint64_t)ptr[4]) << 32;
  85                 /* FALLTHRU */
  86         case 4:
  87                 value |= ((uint32_t)ptr[3]) << 24;
  88                 /* FALLTHRU */
  89         case 3:
  90                 value |= ((uint32_t)ptr[2]) << 16;
  91                 /* FALLTHRU */
  92         case 2:
  93                 value |= ptr[1] << 8;
  94                 /* FALLTHRU */
  95         case 1:
  96                 value |= ptr[0];
  97                 /* FALLTHRU */
  98         case 0:
  99                 break;
 100         }
 101         return value;
 102 #endif
 103 }
 104
 105 void LogicSegment::pack_sample(uint8_t *ptr, uint64_t value)
 106 {
 107 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
 108         *(uint64_t*)ptr = value;
 109 #else
 110         switch (unit_size_) {
 111         default:
 112                 ptr[7] = value >> 56;
 113                 /* FALLTHRU */
 114         case 7:
 115                 ptr[6] = value >> 48;
 116                 /* FALLTHRU */
 117         case 6:
 118                 ptr[5] = value >> 40;
 119                 /* FALLTHRU */
 120         case 5:
 121                 ptr[4] = value >> 32;
 122                 /* FALLTHRU */
 123         case 4:
 124                 ptr[3] = value >> 24;
 125                 /* FALLTHRU */
 126         case 3:
 127                 ptr[2] = value >> 16;
 128                 /* FALLTHRU */
 129         case 2:
 130                 ptr[1] = value >> 8;
 131                 /* FALLTHRU */
 132         case 1:
 133                 ptr[0] = value;
 134                 /* FALLTHRU */
 135         case 0:
 136                 break;
 137         }
 138 #endif
 139 }
 140
 141 void LogicSegment::append_payload(shared_ptr<Logic> logic)
 142 {
 143         assert(unit_size_ == logic->unit_size());
 144         assert((logic->data_length() % unit_size_) == 0);
 145
 146         lock_guard<recursive_mutex> lock(mutex_);
 147
 148         append_data(logic->data_pointer(),
 149                 logic->data_length() / unit_size_);
 150
 151         // Generate the first mip-map from the data
 152         append_payload_to_mipmap();
 153 }
 154
 155 const uint8_t* LogicSegment::get_samples(int64_t start_sample,
 156         int64_t end_sample) const
 157 {
 158         assert(start_sample >= 0);
 159         assert(start_sample <= (int64_t)sample_count_);
 160         assert(end_sample >= 0);
 161         assert(end_sample <= (int64_t)sample_count_);
 162         assert(start_sample <= end_sample);
 163
 164         lock_guard<recursive_mutex> lock(mutex_);
 165
 166         uint8_t* data = new uint8_t[end_sample - start_sample];
 167         const size_t size = (end_sample - start_sample) * unit_size_;
 168         memcpy(data, (uint8_t*)data_.data() + start_sample * unit_size_, size);
 169         return data;
 170 }
 171
 172 void LogicSegment::reallocate_mipmap_level(MipMapLevel &m)
 173 {
 174         const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
 175                 MipMapDataUnit) * MipMapDataUnit;
 176         if (new_data_length > m.data_length) {
 177                 m.data_length = new_data_length;
 178
 179                 // Padding is added to allow for the uint64_t write word
 180                 m.data = realloc(m.data, new_data_length * unit_size_ +
 181                         sizeof(uint64_t));
 182         }
 183 }
 184
 185 void LogicSegment::append_payload_to_mipmap()
 186 {
 187         MipMapLevel &m0 = mip_map_[0];
 188         uint64_t prev_length;
 189         const uint8_t *src_ptr;
 190         uint8_t *dest_ptr;
 191         uint64_t accumulator;
 192         unsigned int diff_counter;
 193
 194         // Expand the data buffer to fit the new samples
 195         prev_length = m0.length;
 196         m0.length = sample_count_ / MipMapScaleFactor;
 197
 198         // Break off if there are no new samples to compute
 199         if (m0.length == prev_length)
 200                 return;
 201
 202         reallocate_mipmap_level(m0);
 203
 204         dest_ptr = (uint8_t*)m0.data + prev_length * unit_size_;
 205
 206         // Iterate through the samples to populate the first level mipmap
 207         const uint8_t *const end_src_ptr = (uint8_t*)data_.data() +
 208                 m0.length * unit_size_ * MipMapScaleFactor;
 209         for (src_ptr = (uint8_t*)data_.data() +
 210                         prev_length * unit_size_ * MipMapScaleFactor;
 211                         src_ptr < end_src_ptr;) {
 212                 // Accumulate transitions which have occurred in this sample
 213                 accumulator = 0;
 214                 diff_counter = MipMapScaleFactor;
 215                 while (diff_counter-- > 0) {
 216                         const uint64_t sample = unpack_sample(src_ptr);
 217                         accumulator |= last_append_sample_ ^ sample;
 218                         last_append_sample_ = sample;
 219                         src_ptr += unit_size_;
 220                 }
 221
 222                 pack_sample(dest_ptr, accumulator);
 223                 dest_ptr += unit_size_;
 224         }
 225
 226         // Compute higher level mipmaps
 227         for (unsigned int level = 1; level < ScaleStepCount; level++) {
 228                 MipMapLevel &m = mip_map_[level];
 229                 const MipMapLevel &ml = mip_map_[level-1];
 230
 231                 // Expand the data buffer to fit the new samples
 232                 prev_length = m.length;
 233                 m.length = ml.length / MipMapScaleFactor;
 234
 235                 // Break off if there are no more samples to computed
 236                 if (m.length == prev_length)
 237                         break;
 238
 239                 reallocate_mipmap_level(m);
 240
 241                 // Subsample the level lower level
 242                 src_ptr = (uint8_t*)ml.data +
 243                         unit_size_ * prev_length * MipMapScaleFactor;
 244                 const uint8_t *const end_dest_ptr =
 245                         (uint8_t*)m.data + unit_size_ * m.length;
 246                 for (dest_ptr = (uint8_t*)m.data +
 247                                 unit_size_ * prev_length;
 248                                 dest_ptr < end_dest_ptr;
 249                                 dest_ptr += unit_size_) {
 250                         accumulator = 0;
 251                         diff_counter = MipMapScaleFactor;
 252                         while (diff_counter-- > 0) {
 253                                 accumulator |= unpack_sample(src_ptr);
 254                                 src_ptr += unit_size_;
 255                         }
 256
 257                         pack_sample(dest_ptr, accumulator);
 258                 }
 259         }
 260 }
 261
 262 uint64_t LogicSegment::get_sample(uint64_t index) const
 263 {
 264         assert(index < sample_count_);
 265
 266         return unpack_sample((uint8_t*)data_.data() + index * unit_size_);
 267 }
 268
 269 void LogicSegment::get_subsampled_edges(
 270         std::vector<EdgePair> &edges,
 271         uint64_t start, uint64_t end,
 272         float min_length, int sig_index)
 273 {
 274         uint64_t index = start;
 275         unsigned int level;
 276         bool last_sample;
 277         bool fast_forward;
 278
 279         assert(end <= get_sample_count());
 280         assert(start <= end);
 281         assert(min_length > 0);
 282         assert(sig_index >= 0);
 283         assert(sig_index < 64);
 284
 285         lock_guard<recursive_mutex> lock(mutex_);
 286
 287         const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
 288         const unsigned int min_level = max((int)floorf(logf(min_length) /
 289                 LogMipMapScaleFactor) - 1, 0);
 290         const uint64_t sig_mask = 1ULL << sig_index;
 291
 292         // Store the initial state
 293         last_sample = (get_sample(start) & sig_mask) != 0;
 294         edges.push_back(pair<int64_t, bool>(index++, last_sample));
 295
 296         while (index + block_length <= end) {
 297                 //----- Continue to search -----//
 298                 level = min_level;
 299
 300                 // We cannot fast-forward if there is no mip-map data at
 301                 // at the minimum level.
 302                 fast_forward = (mip_map_[level].data != nullptr);
 303
 304                 if (min_length < MipMapScaleFactor) {
 305                         // Search individual samples up to the beginning of
 306                         // the next first level mip map block
 307                         const uint64_t final_index = min(end,
 308                                 pow2_ceil(index, MipMapScalePower));
 309
 310                         for (; index < final_index &&
 311                                         (index & ~((uint64_t)(~0) << MipMapScalePower)) != 0;
 312                                         index++) {
 313                                 const bool sample =
 314                                         (get_sample(index) & sig_mask) != 0;
 315
 316                                 // If there was a change we cannot fast forward
 317                                 if (sample != last_sample) {
 318                                         fast_forward = false;
 319                                         break;
 320                                 }
 321                         }
 322                 } else {
 323                         // If resolution is less than a mip map block,
 324                         // round up to the beginning of the mip-map block
 325                         // for this level of detail
 326                         const int min_level_scale_power =
 327                                 (level + 1) * MipMapScalePower;
 328                         index = pow2_ceil(index, min_level_scale_power);
 329                         if (index >= end)
 330                                 break;
 331
 332                         // We can fast forward only if there was no change
 333                         const bool sample =
 334                                 (get_sample(index) & sig_mask) != 0;
 335                         if (last_sample != sample)
 336                                 fast_forward = false;
 337                 }
 338
 339                 if (fast_forward) {
 340
 341                         // Fast forward: This involves zooming out to higher
 342                         // levels of the mip map searching for changes, then
 343                         // zooming in on them to find the point where the edge
 344                         // begins.
 345
 346                         // Slide right and zoom out at the beginnings of mip-map
 347                         // blocks until we encounter a change
 348                         while (1) {
 349                                 const int level_scale_power =
 350                                         (level + 1) * MipMapScalePower;
 351                                 const uint64_t offset =
 352                                         index >> level_scale_power;
 353
 354                                 // Check if we reached the last block at this
 355                                 // level, or if there was a change in this block
 356                                 if (offset >= mip_map_[level].length ||
 357                                         (get_subsample(level, offset) &
 358                                                 sig_mask))
 359                                         break;
 360
 361                                 if ((offset & ~((uint64_t)(~0) << MipMapScalePower)) == 0) {
 362                                         // If we are now at the beginning of a
 363                                         // higher level mip-map block ascend one
 364                                         // level
 365                                         if (level + 1 >= ScaleStepCount ||
 366                                                 !mip_map_[level + 1].data)
 367                                                 break;
 368
 369                                         level++;
 370                                 } else {
 371                                         // Slide right to the beginning of the
 372                                         // next mip map block
 373                                         index = pow2_ceil(index + 1,
 374                                                 level_scale_power);
 375                                 }
 376                         }
 377
 378                         // Zoom in, and slide right until we encounter a change,
 379                         // and repeat until we reach min_level
 380                         while (1) {
 381                                 assert(mip_map_[level].data);
 382
 383                                 const int level_scale_power =
 384                                         (level + 1) * MipMapScalePower;
 385                                 const uint64_t offset =
 386                                         index >> level_scale_power;
 387
 388                                 // Check if we reached the last block at this
 389                                 // level, or if there was a change in this block
 390                                 if (offset >= mip_map_[level].length ||
 391                                                 (get_subsample(level, offset) &
 392                                                 sig_mask)) {
 393                                         // Zoom in unless we reached the minimum
 394                                         // zoom
 395                                         if (level == min_level)
 396                                                 break;
 397
 398                                         level--;
 399                                 } else {
 400                                         // Slide right to the beginning of the
 401                                         // next mip map block
 402                                         index = pow2_ceil(index + 1,
 403                                                 level_scale_power);
 404                                 }
 405                         }
 406
 407                         // If individual samples within the limit of resolution,
 408                         // do a linear search for the next transition within the
 409                         // block
 410                         if (min_length < MipMapScaleFactor) {
 411                                 for (; index < end; index++) {
 412                                         const bool sample = (get_sample(index) &
 413                                                 sig_mask) != 0;
 414                                         if (sample != last_sample)
 415                                                 break;
 416                                 }
 417                         }
 418                 }
 419
 420                 //----- Store the edge -----//
 421
 422                 // Take the last sample of the quanization block
 423                 const int64_t final_index = index + block_length;
 424                 if (index + block_length > end)
 425                         break;
 426
 427                 // Store the final state
 428                 const bool final_sample =
 429                         (get_sample(final_index - 1) & sig_mask) != 0;
 430                 edges.push_back(pair<int64_t, bool>(index, final_sample));
 431
 432                 index = final_index;
 433                 last_sample = final_sample;
 434         }
 435
 436         // Add the final state
 437         const bool end_sample = get_sample(end) & sig_mask;
 438         if (last_sample != end_sample)
 439                 edges.push_back(pair<int64_t, bool>(end, end_sample));
 440         edges.push_back(pair<int64_t, bool>(end + 1, end_sample));
 441 }
 442
 443 uint64_t LogicSegment::get_subsample(int level, uint64_t offset) const
 444 {
 445         assert(level >= 0);
 446         assert(mip_map_[level].data);
 447         return unpack_sample((uint8_t*)mip_map_[level].data +
 448                 unit_size_ * offset);
 449 }
 450
 451 uint64_t LogicSegment::pow2_ceil(uint64_t x, unsigned int power)
 452 {
 453         const uint64_t p = 1 << power;
 454         return (x + p - 1) / p * p;
 455 }
 456
 457 } // namespace data
 458 } // namespace pv