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