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