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