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