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