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