pv/logicdatasnapshot.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 "logicdatasnapshot.h"
  31
  32 using namespace std;
  33
  34 namespace pv {
  35
  36 const int LogicDataSnapshot::MipMapScalePower = 4;
  37 const int LogicDataSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
  38 const float LogicDataSnapshot::LogMipMapScaleFactor = logf(MipMapScaleFactor);
  39 const uint64_t LogicDataSnapshot::MipMapDataUnit = 64*1024;     // bytes
  40
  41 LogicDataSnapshot::LogicDataSnapshot(
  42         const sr_datafeed_logic &logic) :
  43         DataSnapshot(logic.unitsize),
  44         _last_append_sample(0)
  45 {
  46         memset(_mip_map, 0, sizeof(_mip_map));
  47         append_payload(logic);
  48 }
  49
  50 LogicDataSnapshot::~LogicDataSnapshot()
  51 {
  52         BOOST_FOREACH(MipMapLevel &l, _mip_map)
  53                 free(l.data);
  54 }
  55
  56 void LogicDataSnapshot::append_payload(
  57         const sr_datafeed_logic &logic)
  58 {
  59         assert(_unit_size == logic.unitsize);
  60
  61         append_data(logic.data, logic.length);
  62
  63         // Generate the first mip-map from the data
  64         append_payload_to_mipmap();
  65 }
  66
  67 void LogicDataSnapshot::reallocate_mip_map(MipMapLevel &m)
  68 {
  69         const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
  70                 MipMapDataUnit) * MipMapDataUnit;
  71         if(new_data_length > m.data_length)
  72         {
  73                 m.data_length = new_data_length;
  74                 m.data = realloc(m.data, new_data_length * _unit_size);
  75         }
  76 }
  77
  78 void LogicDataSnapshot::append_payload_to_mipmap()
  79 {
  80         MipMapLevel &m0 = _mip_map[0];
  81         uint64_t prev_length;
  82         const uint8_t *src_ptr;
  83         uint8_t *dest_ptr;
  84         uint64_t accumulator;
  85         unsigned int diff_counter;
  86
  87         // Expand the data buffer to fit the new samples
  88         prev_length = m0.length;
  89         m0.length = _sample_count / MipMapScaleFactor;
  90
  91         // Break off if there are no new samples to compute
  92         if(m0.length == prev_length)
  93                 return;
  94
  95         reallocate_mip_map(m0);
  96
  97         dest_ptr = (uint8_t*)m0.data + prev_length * _unit_size;
  98
  99         // Iterate through the samples to populate the first level mipmap
 100         accumulator = 0;
 101         diff_counter = MipMapScaleFactor;
 102         const uint8_t *end_src_ptr = (uint8_t*)_data +
 103                 m0.length * _unit_size * MipMapScaleFactor;
 104         for(src_ptr = (uint8_t*)_data +
 105                 prev_length * _unit_size * MipMapScaleFactor;
 106                 src_ptr < end_src_ptr;)
 107         {
 108                 // Accumulate transitions which have occurred in this sample
 109                 accumulator = 0;
 110                 diff_counter = MipMapScaleFactor;
 111                 while(diff_counter-- > 0)
 112                 {
 113                         const uint64_t sample = *(uint64_t*)src_ptr;
 114                         accumulator |= _last_append_sample ^ sample;
 115                         _last_append_sample = sample;
 116                         src_ptr += _unit_size;
 117                 }
 118
 119                 *(uint64_t*)dest_ptr = accumulator;
 120                 dest_ptr += _unit_size;
 121         }
 122
 123         // Compute higher level mipmaps
 124         for(unsigned int level = 1; level < ScaleStepCount; level++)
 125         {
 126                 MipMapLevel &m = _mip_map[level];
 127                 const MipMapLevel &ml = _mip_map[level-1];
 128
 129                 // Expand the data buffer to fit the new samples
 130                 prev_length = m.length;
 131                 m.length = ml.length / MipMapScaleFactor;
 132
 133                 // Break off if there are no more samples to computed
 134                 if(m.length == prev_length)
 135                         break;
 136
 137                 reallocate_mip_map(m);
 138
 139                 // Subsample the level lower level
 140                 src_ptr = (uint8_t*)ml.data +
 141                         _unit_size * prev_length * MipMapScaleFactor;
 142                 const uint8_t *end_dest_ptr =
 143                         (uint8_t*)m.data + _unit_size * m.length;
 144                 for(dest_ptr = (uint8_t*)m.data +
 145                         _unit_size * prev_length;
 146                         dest_ptr < end_dest_ptr;
 147                         dest_ptr += _unit_size)
 148                 {
 149                         accumulator = 0;
 150                         diff_counter = MipMapScaleFactor;
 151                         while(diff_counter-- > 0)
 152                         {
 153                                 accumulator |= *(uint64_t*)src_ptr;
 154                                 src_ptr += _unit_size;
 155                         }
 156
 157                         *(uint64_t*)dest_ptr = accumulator;
 158                 }
 159         }
 160 }
 161
 162 uint64_t LogicDataSnapshot::get_sample(uint64_t index) const
 163 {
 164         assert(_data);
 165         assert(index >= 0 && index < _sample_count);
 166
 167         return *(uint64_t*)((uint8_t*)_data + index * _unit_size);
 168 }
 169
 170 void LogicDataSnapshot::get_subsampled_edges(
 171         std::vector<EdgePair> &edges,
 172         uint64_t start, uint64_t end,
 173         float min_length, int sig_index)
 174 {
 175         uint64_t index = start;
 176         unsigned int level;
 177         bool last_sample;
 178         bool fast_forward;
 179
 180         assert(start >= 0);
 181         assert(end <= get_sample_count());
 182         assert(start <= end);
 183         assert(min_length > 0);
 184         assert(sig_index >= 0);
 185         assert(sig_index < SR_MAX_NUM_PROBES);
 186
 187         const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
 188         const unsigned int min_level = max((int)floorf(logf(min_length) /
 189                 LogMipMapScaleFactor) - 1, 0);
 190         const uint64_t sig_mask = 1ULL << sig_index;
 191
 192         // Store the initial state
 193         last_sample = (get_sample(start) & sig_mask) != 0;
 194         edges.push_back(pair<int64_t, bool>(index++, last_sample));
 195
 196         while(index + block_length <= end)
 197         {
 198                 //----- Continue to search -----//
 199                 level = min_level;
 200                 fast_forward = true;
 201
 202                 if(min_length < MipMapScaleFactor)
 203                 {
 204                         // Search individual samples up to the beginning of
 205                         // the next first level mip map block
 206                         const uint64_t final_index = min(end,
 207                                 pow2_ceil(index, MipMapScalePower));
 208
 209                         for(; index < final_index &&
 210                                 (index & ~(~0 << MipMapScalePower)) != 0;
 211                                 index++)
 212                         {
 213                                 const bool sample =
 214                                         (get_sample(index) & sig_mask) != 0;
 215
 216                                 // If there was a change we cannot fast forward
 217                                 if(sample != last_sample) {
 218                                         fast_forward = false;
 219                                         break;
 220                                 }
 221                         }
 222                 }
 223                 else
 224                 {
 225                         // If resolution is less than a mip map block,
 226                         // round up to the beginning of the mip-map block
 227                         // for this level of detail
 228                         const int min_level_scale_power =
 229                                 (level + 1) * MipMapScalePower;
 230                         index = pow2_ceil(index, min_level_scale_power);
 231                         if(index >= end)
 232                                 break;
 233
 234                         // We can fast forward only if there was no change
 235                         const bool sample =
 236                                 (get_sample(index) & sig_mask) != 0;
 237                         fast_forward = last_sample == sample;
 238                 }
 239
 240                 if(fast_forward) {
 241
 242                         // Fast forward: This involves zooming out to higher
 243                         // levels of the mip map searching for changes, then
 244                         // zooming in on them to find the point where the edge
 245                         // begins.
 246
 247                         // Slide right and zoom out at the beginnings of mip-map
 248                         // blocks until we encounter a change
 249                         while(1) {
 250                                 const int level_scale_power =
 251                                         (level + 1) * MipMapScalePower;
 252                                 const uint64_t offset =
 253                                         index >> level_scale_power;
 254                                 assert(offset >= 0);
 255
 256                                 // Check if we reached the last block at this
 257                                 // level, or if there was a change in this block
 258                                 if(offset >= _mip_map[level].length ||
 259                                         (get_subsample(level, offset) &
 260                                                 sig_mask))
 261                                         break;
 262
 263                                 if((offset & ~(~0 << MipMapScalePower)) == 0) {
 264                                         // If we are now at the beginning of a
 265                                         // higher level mip-map block ascend one
 266                                         // level
 267                                         if(level + 1 >= ScaleStepCount ||
 268                                                 !_mip_map[level + 1].data)
 269                                                 break;
 270
 271                                         level++;
 272                                 } else {
 273                                         // Slide right to the beginning of the
 274                                         // next mip map block
 275                                         index = pow2_ceil(index + 1,
 276                                                 level_scale_power);
 277                                 }
 278                         }
 279
 280                         // Zoom in, and slide right until we encounter a change,
 281                         // and repeat until we reach min_level
 282                         while(1) {
 283                                 assert(_mip_map[level].data);
 284
 285                                 const int level_scale_power =
 286                                         (level + 1) * MipMapScalePower;
 287                                 const uint64_t offset =
 288                                         index >> level_scale_power;
 289                                 assert(offset >= 0);
 290
 291                                 // Check if we reached the last block at this
 292                                 // level, or if there was a change in this block
 293                                 if(offset >= _mip_map[level].length ||
 294                                         (get_subsample(level, offset) &
 295                                                 sig_mask)) {
 296                                         // Zoom in unless we reached the minimum
 297                                         // zoom
 298                                         if(level == min_level)
 299                                                 break;
 300
 301                                         level--;
 302                                 } else {
 303                                         // Slide right to the beginning of the
 304                                         // next mip map block
 305                                         index = pow2_ceil(index + 1,
 306                                                 level_scale_power);
 307                                 }
 308                         }
 309
 310                         // If individual samples within the limit of resolution,
 311                         // do a linear search for the next transition within the
 312                         // block
 313                         if(min_length < MipMapScaleFactor) {
 314                                 for(; index < end; index++) {
 315                                         const bool sample = (get_sample(index) &
 316                                                 sig_mask) != 0;
 317                                         if(sample != last_sample)
 318                                                 break;
 319                                 }
 320                         }
 321                 }
 322
 323                 //----- Store the edge -----//
 324
 325                 // Take the last sample of the quanization block
 326                 const int64_t final_index = index + block_length;
 327                 if(index + block_length > end)
 328                         break;
 329
 330                 // Store the final state
 331                 const bool final_sample =
 332                         (get_sample(final_index - 1) & sig_mask) != 0;
 333                 edges.push_back(pair<int64_t, bool>(index, final_sample));
 334
 335                 index = final_index;
 336                 last_sample = final_sample;
 337         }
 338
 339         // Add the final state
 340         edges.push_back(pair<int64_t, bool>(end,
 341                 get_sample(end) & sig_mask));
 342 }
 343
 344 uint64_t LogicDataSnapshot::get_subsample(int level, uint64_t offset) const
 345 {
 346         assert(level >= 0);
 347         assert(_mip_map[level].data);
 348         return *(uint64_t*)((uint8_t*)_mip_map[level].data +
 349                 _unit_size * offset);
 350 }
 351
 352 uint64_t LogicDataSnapshot::pow2_ceil(uint64_t x, unsigned int power)
 353 {
 354         const uint64_t p = 1 << power;
 355         return (x + p - 1) / p * p;
 356 }
 357
 358 } // namespace pv