pv/data/logicsnapshot.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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <extdef.h>
  22
  23 #include <assert.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <math.h>
  27
  28 #include "logicsnapshot.hpp"
  29
  30 #include <libsigrok/libsigrok.hpp>
  31
  32 using std::lock_guard;
  33 using std::recursive_mutex;
  34 using std::max;
  35 using std::min;
  36 using std::pair;
  37 using std::shared_ptr;
  38
  39 using sigrok::Logic;
  40
  41 namespace pv {
  42 namespace data {
  43
  44 const int LogicSnapshot::MipMapScalePower = 4;
  45 const int LogicSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
  46 const float LogicSnapshot::LogMipMapScaleFactor = logf(MipMapScaleFactor);
  47 const uint64_t LogicSnapshot::MipMapDataUnit = 64*1024; // bytes
  48
  49 LogicSnapshot::LogicSnapshot(shared_ptr<Logic> logic, uint64_t samplerate,
  50                              const uint64_t expected_num_samples) :
  51         Snapshot(samplerate, logic->unit_size()),
  52         last_append_sample_(0)
  53 {
  54         set_capacity(expected_num_samples);
  55
  56         lock_guard<recursive_mutex> lock(mutex_);
  57         memset(mip_map_, 0, sizeof(mip_map_));
  58         append_payload(logic);
  59 }
  60
  61 LogicSnapshot::~LogicSnapshot()
  62 {
  63         lock_guard<recursive_mutex> lock(mutex_);
  64         for (MipMapLevel &l : mip_map_)
  65                 free(l.data);
  66 }
  67
  68 uint64_t LogicSnapshot::unpack_sample(const uint8_t *ptr) const
  69 {
  70 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
  71         return *(uint64_t*)ptr;
  72 #else
  73         uint64_t value = 0;
  74         switch(unit_size_) {
  75         default:
  76                 value |= ((uint64_t)ptr[7]) << 56;
  77                 /* FALLTHRU */
  78         case 7:
  79                 value |= ((uint64_t)ptr[6]) << 48;
  80                 /* FALLTHRU */
  81         case 6:
  82                 value |= ((uint64_t)ptr[5]) << 40;
  83                 /* FALLTHRU */
  84         case 5:
  85                 value |= ((uint64_t)ptr[4]) << 32;
  86                 /* FALLTHRU */
  87         case 4:
  88                 value |= ((uint32_t)ptr[3]) << 24;
  89                 /* FALLTHRU */
  90         case 3:
  91                 value |= ((uint32_t)ptr[2]) << 16;
  92                 /* FALLTHRU */
  93         case 2:
  94                 value |= ptr[1] << 8;
  95                 /* FALLTHRU */
  96         case 1:
  97                 value |= ptr[0];
  98                 /* FALLTHRU */
  99         case 0:
 100                 break;
 101         }
 102         return value;
 103 #endif
 104 }
 105
 106 void LogicSnapshot::pack_sample(uint8_t *ptr, uint64_t value)
 107 {
 108 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
 109         *(uint64_t*)ptr = value;
 110 #else
 111         switch(unit_size_) {
 112         default:
 113                 ptr[7] = value >> 56;
 114                 /* FALLTHRU */
 115         case 7:
 116                 ptr[6] = value >> 48;
 117                 /* FALLTHRU */
 118         case 6:
 119                 ptr[5] = value >> 40;
 120                 /* FALLTHRU */
 121         case 5:
 122                 ptr[4] = value >> 32;
 123                 /* FALLTHRU */
 124         case 4:
 125                 ptr[3] = value >> 24;
 126                 /* FALLTHRU */
 127         case 3:
 128                 ptr[2] = value >> 16;
 129                 /* FALLTHRU */
 130         case 2:
 131                 ptr[1] = value >> 8;
 132                 /* FALLTHRU */
 133         case 1:
 134                 ptr[0] = value;
 135                 /* FALLTHRU */
 136         case 0:
 137                 break;
 138         }
 139 #endif
 140 }
 141
 142 void LogicSnapshot::append_payload(shared_ptr<Logic> logic)
 143 {
 144         assert(unit_size_ == logic->unit_size());
 145         assert((logic->data_length() % unit_size_) == 0);
 146
 147         lock_guard<recursive_mutex> lock(mutex_);
 148
 149         append_data(logic->data_pointer(),
 150                 logic->data_length() / unit_size_);
 151
 152         // Generate the first mip-map from the data
 153         append_payload_to_mipmap();
 154 }
 155
 156 void LogicSnapshot::get_samples(uint8_t *const data,
 157         int64_t start_sample, int64_t end_sample) const
 158 {
 159         assert(data);
 160         assert(start_sample >= 0);
 161         assert(start_sample <= (int64_t)sample_count_);
 162         assert(end_sample >= 0);
 163         assert(end_sample <= (int64_t)sample_count_);
 164         assert(start_sample <= end_sample);
 165
 166         lock_guard<recursive_mutex> lock(mutex_);
 167
 168         const size_t size = (end_sample - start_sample) * unit_size_;
 169         memcpy(data, (const uint8_t*)data_.data() + start_sample * unit_size_, size);
 170 }
 171
 172 void LogicSnapshot::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         {
 178                 m.data_length = new_data_length;
 179
 180                 // Padding is added to allow for the uint64_t write word
 181                 m.data = realloc(m.data, new_data_length * unit_size_ +
 182                         sizeof(uint64_t));
 183         }
 184 }
 185
 186 void LogicSnapshot::append_payload_to_mipmap()
 187 {
 188         MipMapLevel &m0 = mip_map_[0];
 189         uint64_t prev_length;
 190         const uint8_t *src_ptr;
 191         uint8_t *dest_ptr;
 192         uint64_t accumulator;
 193         unsigned int diff_counter;
 194
 195         // Expand the data buffer to fit the new samples
 196         prev_length = m0.length;
 197         m0.length = sample_count_ / MipMapScaleFactor;
 198
 199         // Break off if there are no new samples to compute
 200         if (m0.length == prev_length)
 201                 return;
 202
 203         reallocate_mipmap_level(m0);
 204
 205         dest_ptr = (uint8_t*)m0.data + prev_length * unit_size_;
 206
 207         // Iterate through the samples to populate the first level mipmap
 208         const uint8_t *const end_src_ptr = (uint8_t*)data_.data() +
 209                 m0.length * unit_size_ * MipMapScaleFactor;
 210         for (src_ptr = (uint8_t*)data_.data() +
 211                 prev_length * unit_size_ * MipMapScaleFactor;
 212                 src_ptr < end_src_ptr;)
 213         {
 214                 // Accumulate transitions which have occurred in this sample
 215                 accumulator = 0;
 216                 diff_counter = MipMapScaleFactor;
 217                 while (diff_counter-- > 0)
 218                 {
 219                         const uint64_t sample = unpack_sample(src_ptr);
 220                         accumulator |= last_append_sample_ ^ sample;
 221                         last_append_sample_ = sample;
 222                         src_ptr += unit_size_;
 223                 }
 224
 225                 pack_sample(dest_ptr, accumulator);
 226                 dest_ptr += unit_size_;
 227         }
 228
 229         // Compute higher level mipmaps
 230         for (unsigned int level = 1; level < ScaleStepCount; level++)
 231         {
 232                 MipMapLevel &m = mip_map_[level];
 233                 const MipMapLevel &ml = mip_map_[level-1];
 234
 235                 // Expand the data buffer to fit the new samples
 236                 prev_length = m.length;
 237                 m.length = ml.length / MipMapScaleFactor;
 238
 239                 // Break off if there are no more samples to computed
 240                 if (m.length == prev_length)
 241                         break;
 242
 243                 reallocate_mipmap_level(m);
 244
 245                 // Subsample the level lower level
 246                 src_ptr = (uint8_t*)ml.data +
 247                         unit_size_ * prev_length * MipMapScaleFactor;
 248                 const uint8_t *const end_dest_ptr =
 249                         (uint8_t*)m.data + unit_size_ * m.length;
 250                 for (dest_ptr = (uint8_t*)m.data +
 251                         unit_size_ * prev_length;
 252                         dest_ptr < end_dest_ptr;
 253                         dest_ptr += unit_size_)
 254                 {
 255                         accumulator = 0;
 256                         diff_counter = MipMapScaleFactor;
 257                         while (diff_counter-- > 0)
 258                         {
 259                                 accumulator |= unpack_sample(src_ptr);
 260                                 src_ptr += unit_size_;
 261                         }
 262
 263                         pack_sample(dest_ptr, accumulator);
 264                 }
 265         }
 266 }
 267
 268 uint64_t LogicSnapshot::get_sample(uint64_t index) const
 269 {
 270         assert(index < sample_count_);
 271
 272         return unpack_sample((uint8_t*)data_.data() + index * unit_size_);
 273 }
 274
 275 void LogicSnapshot::get_subsampled_edges(
 276         std::vector<EdgePair> &edges,
 277         uint64_t start, uint64_t end,
 278         float min_length, int sig_index)
 279 {
 280         uint64_t index = start;
 281         unsigned int level;
 282         bool last_sample;
 283         bool fast_forward;
 284
 285         assert(end <= get_sample_count());
 286         assert(start <= end);
 287         assert(min_length > 0);
 288         assert(sig_index >= 0);
 289         assert(sig_index < 64);
 290
 291         lock_guard<recursive_mutex> lock(mutex_);
 292
 293         const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
 294         const unsigned int min_level = max((int)floorf(logf(min_length) /
 295                 LogMipMapScaleFactor) - 1, 0);
 296         const uint64_t sig_mask = 1ULL << sig_index;
 297
 298         // Store the initial state
 299         last_sample = (get_sample(start) & sig_mask) != 0;
 300         edges.push_back(pair<int64_t, bool>(index++, last_sample));
 301
 302         while (index + block_length <= end)
 303         {
 304                 //----- Continue to search -----//
 305                 level = min_level;
 306
 307                 // We cannot fast-forward if there is no mip-map data at
 308                 // at the minimum level.
 309                 fast_forward = (mip_map_[level].data != NULL);
 310
 311                 if (min_length < MipMapScaleFactor)
 312                 {
 313                         // Search individual samples up to the beginning of
 314                         // the next first level mip map block
 315                         const uint64_t final_index = min(end,
 316                                 pow2_ceil(index, MipMapScalePower));
 317
 318                         for (; index < final_index &&
 319                                 (index & ~(~0 << MipMapScalePower)) != 0;
 320                                 index++)
 321                         {
 322                                 const bool sample =
 323                                         (get_sample(index) & sig_mask) != 0;
 324
 325                                 // If there was a change we cannot fast forward
 326                                 if (sample != last_sample) {
 327                                         fast_forward = false;
 328                                         break;
 329                                 }
 330                         }
 331                 }
 332                 else
 333                 {
 334                         // If resolution is less than a mip map block,
 335                         // round up to the beginning of the mip-map block
 336                         // for this level of detail
 337                         const int min_level_scale_power =
 338                                 (level + 1) * MipMapScalePower;
 339                         index = pow2_ceil(index, min_level_scale_power);
 340                         if (index >= end)
 341                                 break;
 342
 343                         // We can fast forward only if there was no change
 344                         const bool sample =
 345                                 (get_sample(index) & sig_mask) != 0;
 346                         if (last_sample != sample)
 347                                 fast_forward = false;
 348                 }
 349
 350                 if (fast_forward) {
 351
 352                         // Fast forward: This involves zooming out to higher
 353                         // levels of the mip map searching for changes, then
 354                         // zooming in on them to find the point where the edge
 355                         // begins.
 356
 357                         // Slide right and zoom out at the beginnings of mip-map
 358                         // blocks until we encounter a change
 359                         while (1) {
 360                                 const int level_scale_power =
 361                                         (level + 1) * MipMapScalePower;
 362                                 const uint64_t offset =
 363                                         index >> level_scale_power;
 364
 365                                 // Check if we reached the last block at this
 366                                 // level, or if there was a change in this block
 367                                 if (offset >= mip_map_[level].length ||
 368                                         (get_subsample(level, offset) &
 369                                                 sig_mask))
 370                                         break;
 371
 372                                 if ((offset & ~(~0 << MipMapScalePower)) == 0) {
 373                                         // If we are now at the beginning of a
 374                                         // higher level mip-map block ascend one
 375                                         // level
 376                                         if (level + 1 >= ScaleStepCount ||
 377                                                 !mip_map_[level + 1].data)
 378                                                 break;
 379
 380                                         level++;
 381                                 } else {
 382                                         // Slide right to the beginning of the
 383                                         // next mip map block
 384                                         index = pow2_ceil(index + 1,
 385                                                 level_scale_power);
 386                                 }
 387                         }
 388
 389                         // Zoom in, and slide right until we encounter a change,
 390                         // and repeat until we reach min_level
 391                         while (1) {
 392                                 assert(mip_map_[level].data);
 393
 394                                 const int level_scale_power =
 395                                         (level + 1) * MipMapScalePower;
 396                                 const uint64_t offset =
 397                                         index >> level_scale_power;
 398
 399                                 // Check if we reached the last block at this
 400                                 // level, or if there was a change in this block
 401                                 if (offset >= mip_map_[level].length ||
 402                                         (get_subsample(level, offset) &
 403                                                 sig_mask)) {
 404                                         // Zoom in unless we reached the minimum
 405                                         // zoom
 406                                         if (level == min_level)
 407                                                 break;
 408
 409                                         level--;
 410                                 } else {
 411                                         // Slide right to the beginning of the
 412                                         // next mip map block
 413                                         index = pow2_ceil(index + 1,
 414                                                 level_scale_power);
 415                                 }
 416                         }
 417
 418                         // If individual samples within the limit of resolution,
 419                         // do a linear search for the next transition within the
 420                         // block
 421                         if (min_length < MipMapScaleFactor) {
 422                                 for (; index < end; index++) {
 423                                         const bool sample = (get_sample(index) &
 424                                                 sig_mask) != 0;
 425                                         if (sample != last_sample)
 426                                                 break;
 427                                 }
 428                         }
 429                 }
 430
 431                 //----- Store the edge -----//
 432
 433                 // Take the last sample of the quanization block
 434                 const int64_t final_index = index + block_length;
 435                 if (index + block_length > end)
 436                         break;
 437
 438                 // Store the final state
 439                 const bool final_sample =
 440                         (get_sample(final_index - 1) & sig_mask) != 0;
 441                 edges.push_back(pair<int64_t, bool>(index, final_sample));
 442
 443                 index = final_index;
 444                 last_sample = final_sample;
 445         }
 446
 447         // Add the final state
 448         const bool end_sample = get_sample(end) & sig_mask;
 449         if (last_sample != end_sample)
 450                 edges.push_back(pair<int64_t, bool>(end, end_sample));
 451         edges.push_back(pair<int64_t, bool>(end + 1, end_sample));
 452 }
 453
 454 uint64_t LogicSnapshot::get_subsample(int level, uint64_t offset) const
 455 {
 456         assert(level >= 0);
 457         assert(mip_map_[level].data);
 458         return unpack_sample((uint8_t*)mip_map_[level].data +
 459                 unit_size_ * offset);
 460 }
 461
 462 uint64_t LogicSnapshot::pow2_ceil(uint64_t x, unsigned int power)
 463 {
 464         const uint64_t p = 1 << power;
 465         return (x + p - 1) / p * p;
 466 }
 467
 468 } // namespace data
 469 } // namespace pv