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