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