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