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