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 "config.h"
  29 #include "logicsnapshot.h"
  30
  31 #include <libsigrok/libsigrok.hpp>
  32
  33 using std::lock_guard;
  34 using std::recursive_mutex;
  35 using std::max;
  36 using std::min;
  37 using std::pair;
  38 using std::shared_ptr;
  39
  40 using sigrok::Logic;
  41
  42 namespace pv {
  43 namespace data {
  44
  45 const int LogicSnapshot::MipMapScalePower = 4;
  46 const int LogicSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
  47 const float LogicSnapshot::LogMipMapScaleFactor = logf(MipMapScaleFactor);
  48 const uint64_t LogicSnapshot::MipMapDataUnit = 64*1024; // bytes
  49
  50 LogicSnapshot::LogicSnapshot(shared_ptr<Logic> logic,
  51                              const uint64_t expected_num_samples) :
  52         Snapshot(logic->unit_size()),
  53         _last_append_sample(0)
  54 {
  55         set_capacity(expected_num_samples);
  56
  57         lock_guard<recursive_mutex> lock(_mutex);
  58         memset(_mip_map, 0, sizeof(_mip_map));
  59         append_payload(logic);
  60 }
  61
  62 LogicSnapshot::~LogicSnapshot()
  63 {
  64         lock_guard<recursive_mutex> lock(_mutex);
  65         for (MipMapLevel &l : _mip_map)
  66                 free(l.data);
  67 }
  68
  69 uint64_t LogicSnapshot::unpack_sample(const uint8_t *ptr) const
  70 {
  71 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
  72         return *(uint64_t*)ptr;
  73 #else
  74         uint64_t value = 0;
  75         switch(_unit_size) {
  76         default:
  77                 value |= ((uint64_t)ptr[7]) << 56;
  78                 /* FALLTHRU */
  79         case 7:
  80                 value |= ((uint64_t)ptr[6]) << 48;
  81                 /* FALLTHRU */
  82         case 6:
  83                 value |= ((uint64_t)ptr[5]) << 40;
  84                 /* FALLTHRU */
  85         case 5:
  86                 value |= ((uint64_t)ptr[4]) << 32;
  87                 /* FALLTHRU */
  88         case 4:
  89                 value |= ((uint32_t)ptr[3]) << 24;
  90                 /* FALLTHRU */
  91         case 3:
  92                 value |= ((uint32_t)ptr[2]) << 16;
  93                 /* FALLTHRU */
  94         case 2:
  95                 value |= ptr[1] << 8;
  96                 /* FALLTHRU */
  97         case 1:
  98                 value |= ptr[0];
  99                 /* FALLTHRU */
 100         case 0:
 101                 break;
 102         }
 103         return value;
 104 #endif
 105 }
 106
 107 void LogicSnapshot::pack_sample(uint8_t *ptr, uint64_t value)
 108 {
 109 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
 110         *(uint64_t*)ptr = value;
 111 #else
 112         switch(_unit_size) {
 113         default:
 114                 ptr[7] = value >> 56;
 115                 /* FALLTHRU */
 116         case 7:
 117                 ptr[6] = value >> 48;
 118                 /* FALLTHRU */
 119         case 6:
 120                 ptr[5] = value >> 40;
 121                 /* FALLTHRU */
 122         case 5:
 123                 ptr[4] = value >> 32;
 124                 /* FALLTHRU */
 125         case 4:
 126                 ptr[3] = value >> 24;
 127                 /* FALLTHRU */
 128         case 3:
 129                 ptr[2] = value >> 16;
 130                 /* FALLTHRU */
 131         case 2:
 132                 ptr[1] = value >> 8;
 133                 /* FALLTHRU */
 134         case 1:
 135                 ptr[0] = value;
 136                 /* FALLTHRU */
 137         case 0:
 138                 break;
 139         }
 140 #endif
 141 }
 142
 143 void LogicSnapshot::append_payload(shared_ptr<Logic> logic)
 144 {
 145         assert(_unit_size == logic->unit_size());
 146         assert((logic->data_length() % _unit_size) == 0);
 147
 148         lock_guard<recursive_mutex> lock(_mutex);
 149
 150         append_data(logic->data_pointer(),
 151                 logic->data_length() / _unit_size);
 152
 153         // Generate the first mip-map from the data
 154         append_payload_to_mipmap();
 155 }
 156
 157 void LogicSnapshot::get_samples(uint8_t *const data,
 158         int64_t start_sample, int64_t end_sample) const
 159 {
 160         assert(data);
 161         assert(start_sample >= 0);
 162         assert(start_sample <= (int64_t)_sample_count);
 163         assert(end_sample >= 0);
 164         assert(end_sample <= (int64_t)_sample_count);
 165         assert(start_sample <= end_sample);
 166
 167         lock_guard<recursive_mutex> lock(_mutex);
 168
 169         const size_t size = (end_sample - start_sample) * _unit_size;
 170         memcpy(data, (const uint8_t*)_data.data() + start_sample * _unit_size, size);
 171 }
 172
 173 void LogicSnapshot::reallocate_mipmap_level(MipMapLevel &m)
 174 {
 175         const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
 176                 MipMapDataUnit) * MipMapDataUnit;
 177         if (new_data_length > m.data_length)
 178         {
 179                 m.data_length = new_data_length;
 180
 181                 // Padding is added to allow for the uint64_t write word
 182                 m.data = realloc(m.data, new_data_length * _unit_size +
 183                         sizeof(uint64_t));
 184         }
 185 }
 186
 187 void LogicSnapshot::append_payload_to_mipmap()
 188 {
 189         MipMapLevel &m0 = _mip_map[0];
 190         uint64_t prev_length;
 191         const uint8_t *src_ptr;
 192         uint8_t *dest_ptr;
 193         uint64_t accumulator;
 194         unsigned int diff_counter;
 195
 196         // Expand the data buffer to fit the new samples
 197         prev_length = m0.length;
 198         m0.length = _sample_count / MipMapScaleFactor;
 199
 200         // Break off if there are no new samples to compute
 201         if (m0.length == prev_length)
 202                 return;
 203
 204         reallocate_mipmap_level(m0);
 205
 206         dest_ptr = (uint8_t*)m0.data + prev_length * _unit_size;
 207
 208         // Iterate through the samples to populate the first level mipmap
 209         const uint8_t *const end_src_ptr = (uint8_t*)_data.data() +
 210                 m0.length * _unit_size * MipMapScaleFactor;
 211         for (src_ptr = (uint8_t*)_data.data() +
 212                 prev_length * _unit_size * MipMapScaleFactor;
 213                 src_ptr < end_src_ptr;)
 214         {
 215                 // Accumulate transitions which have occurred in this sample
 216                 accumulator = 0;
 217                 diff_counter = MipMapScaleFactor;
 218                 while (diff_counter-- > 0)
 219                 {
 220                         const uint64_t sample = unpack_sample(src_ptr);
 221                         accumulator |= _last_append_sample ^ sample;
 222                         _last_append_sample = sample;
 223                         src_ptr += _unit_size;
 224                 }
 225
 226                 pack_sample(dest_ptr, accumulator);
 227                 dest_ptr += _unit_size;
 228         }
 229
 230         // Compute higher level mipmaps
 231         for (unsigned int level = 1; level < ScaleStepCount; level++)
 232         {
 233                 MipMapLevel &m = _mip_map[level];
 234                 const MipMapLevel &ml = _mip_map[level-1];
 235
 236                 // Expand the data buffer to fit the new samples
 237                 prev_length = m.length;
 238                 m.length = ml.length / MipMapScaleFactor;
 239
 240                 // Break off if there are no more samples to computed
 241                 if (m.length == prev_length)
 242                         break;
 243
 244                 reallocate_mipmap_level(m);
 245
 246                 // Subsample the level lower level
 247                 src_ptr = (uint8_t*)ml.data +
 248                         _unit_size * prev_length * MipMapScaleFactor;
 249                 const uint8_t *const end_dest_ptr =
 250                         (uint8_t*)m.data + _unit_size * m.length;
 251                 for (dest_ptr = (uint8_t*)m.data +
 252                         _unit_size * prev_length;
 253                         dest_ptr < end_dest_ptr;
 254                         dest_ptr += _unit_size)
 255                 {
 256                         accumulator = 0;
 257                         diff_counter = MipMapScaleFactor;
 258                         while (diff_counter-- > 0)
 259                         {
 260                                 accumulator |= unpack_sample(src_ptr);
 261                                 src_ptr += _unit_size;
 262                         }
 263
 264                         pack_sample(dest_ptr, accumulator);
 265                 }
 266         }
 267 }
 268
 269 uint64_t LogicSnapshot::get_sample(uint64_t index) const
 270 {
 271         assert(index < _sample_count);
 272
 273         return unpack_sample((uint8_t*)_data.data() + index * _unit_size);
 274 }
 275
 276 void LogicSnapshot::get_subsampled_edges(
 277         std::vector<EdgePair> &edges,
 278         uint64_t start, uint64_t end,
 279         float min_length, int sig_index)
 280 {
 281         uint64_t index = start;
 282         unsigned int level;
 283         bool last_sample;
 284         bool fast_forward;
 285
 286         assert(end <= get_sample_count());
 287         assert(start <= end);
 288         assert(min_length > 0);
 289         assert(sig_index >= 0);
 290         assert(sig_index < 64);
 291
 292         lock_guard<recursive_mutex> lock(_mutex);
 293
 294         const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
 295         const unsigned int min_level = max((int)floorf(logf(min_length) /
 296                 LogMipMapScaleFactor) - 1, 0);
 297         const uint64_t sig_mask = 1ULL << sig_index;
 298
 299         // Store the initial state
 300         last_sample = (get_sample(start) & sig_mask) != 0;
 301         edges.push_back(pair<int64_t, bool>(index++, last_sample));
 302
 303         while (index + block_length <= end)
 304         {
 305                 //----- Continue to search -----//
 306                 level = min_level;
 307
 308                 // We cannot fast-forward if there is no mip-map data at
 309                 // at the minimum level.
 310                 fast_forward = (_mip_map[level].data != NULL);
 311
 312                 if (min_length < MipMapScaleFactor)
 313                 {
 314                         // Search individual samples up to the beginning of
 315                         // the next first level mip map block
 316                         const uint64_t final_index = min(end,
 317                                 pow2_ceil(index, MipMapScalePower));
 318
 319                         for (; index < final_index &&
 320                                 (index & ~(~0 << MipMapScalePower)) != 0;
 321                                 index++)
 322                         {
 323                                 const bool sample =
 324                                         (get_sample(index) & sig_mask) != 0;
 325
 326                                 // If there was a change we cannot fast forward
 327                                 if (sample != last_sample) {
 328                                         fast_forward = false;
 329                                         break;
 330                                 }
 331                         }
 332                 }
 333                 else
 334                 {
 335                         // If resolution is less than a mip map block,
 336                         // round up to the beginning of the mip-map block
 337                         // for this level of detail
 338                         const int min_level_scale_power =
 339                                 (level + 1) * MipMapScalePower;
 340                         index = pow2_ceil(index, min_level_scale_power);
 341                         if (index >= end)
 342                                 break;
 343
 344                         // We can fast forward only if there was no change
 345                         const bool sample =
 346                                 (get_sample(index) & sig_mask) != 0;
 347                         if (last_sample != sample)
 348                                 fast_forward = false;
 349                 }
 350
 351                 if (fast_forward) {
 352
 353                         // Fast forward: This involves zooming out to higher
 354                         // levels of the mip map searching for changes, then
 355                         // zooming in on them to find the point where the edge
 356                         // begins.
 357
 358                         // Slide right and zoom out at the beginnings of mip-map
 359                         // blocks until we encounter a change
 360                         while (1) {
 361                                 const int level_scale_power =
 362                                         (level + 1) * MipMapScalePower;
 363                                 const uint64_t offset =
 364                                         index >> level_scale_power;
 365
 366                                 // Check if we reached the last block at this
 367                                 // level, or if there was a change in this block
 368                                 if (offset >= _mip_map[level].length ||
 369                                         (get_subsample(level, offset) &
 370                                                 sig_mask))
 371                                         break;
 372
 373                                 if ((offset & ~(~0 << MipMapScalePower)) == 0) {
 374                                         // If we are now at the beginning of a
 375                                         // higher level mip-map block ascend one
 376                                         // level
 377                                         if (level + 1 >= ScaleStepCount ||
 378                                                 !_mip_map[level + 1].data)
 379                                                 break;
 380
 381                                         level++;
 382                                 } else {
 383                                         // Slide right to the beginning of the
 384                                         // next mip map block
 385                                         index = pow2_ceil(index + 1,
 386                                                 level_scale_power);
 387                                 }
 388                         }
 389
 390                         // Zoom in, and slide right until we encounter a change,
 391                         // and repeat until we reach min_level
 392                         while (1) {
 393                                 assert(_mip_map[level].data);
 394
 395                                 const int level_scale_power =
 396                                         (level + 1) * MipMapScalePower;
 397                                 const uint64_t offset =
 398                                         index >> level_scale_power;
 399
 400                                 // Check if we reached the last block at this
 401                                 // level, or if there was a change in this block
 402                                 if (offset >= _mip_map[level].length ||
 403                                         (get_subsample(level, offset) &
 404                                                 sig_mask)) {
 405                                         // Zoom in unless we reached the minimum
 406                                         // zoom
 407                                         if (level == min_level)
 408                                                 break;
 409
 410                                         level--;
 411                                 } else {
 412                                         // Slide right to the beginning of the
 413                                         // next mip map block
 414                                         index = pow2_ceil(index + 1,
 415                                                 level_scale_power);
 416                                 }
 417                         }
 418
 419                         // If individual samples within the limit of resolution,
 420                         // do a linear search for the next transition within the
 421                         // block
 422                         if (min_length < MipMapScaleFactor) {
 423                                 for (; index < end; index++) {
 424                                         const bool sample = (get_sample(index) &
 425                                                 sig_mask) != 0;
 426                                         if (sample != last_sample)
 427                                                 break;
 428                                 }
 429                         }
 430                 }
 431
 432                 //----- Store the edge -----//
 433
 434                 // Take the last sample of the quanization block
 435                 const int64_t final_index = index + block_length;
 436                 if (index + block_length > end)
 437                         break;
 438
 439                 // Store the final state
 440                 const bool final_sample =
 441                         (get_sample(final_index - 1) & sig_mask) != 0;
 442                 edges.push_back(pair<int64_t, bool>(index, final_sample));
 443
 444                 index = final_index;
 445                 last_sample = final_sample;
 446         }
 447
 448         // Add the final state
 449         const bool end_sample = get_sample(end) & sig_mask;
 450         if (last_sample != end_sample)
 451                 edges.push_back(pair<int64_t, bool>(end, end_sample));
 452         edges.push_back(pair<int64_t, bool>(end + 1, end_sample));
 453 }
 454
 455 uint64_t LogicSnapshot::get_subsample(int level, uint64_t offset) const
 456 {
 457         assert(level >= 0);
 458         assert(_mip_map[level].data);
 459         return unpack_sample((uint8_t*)_mip_map[level].data +
 460                 _unit_size * offset);
 461 }
 462
 463 uint64_t LogicSnapshot::pow2_ceil(uint64_t x, unsigned int power)
 464 {
 465         const uint64_t p = 1 << power;
 466         return (x + p - 1) / p * p;
 467 }
 468
 469 } // namespace data
 470 } // namespace pv