pv/data/segment.cpp

   1 /*
   2  * This file is part of the PulseView project.
   3  *
   4  * Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
   5  * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "segment.hpp"
  22
  23 #include <cassert>
  24 #include <cstdlib>
  25 #include <cstring>
  26
  27 #include <QDebug>
  28
  29 using std::bad_alloc;
  30 using std::lock_guard;
  31 using std::min;
  32 using std::recursive_mutex;
  33
  34 namespace pv {
  35 namespace data {
  36
  37 const uint64_t Segment::MaxChunkSize = 10 * 1024 * 1024;  /* 10MiB */
  38
  39 Segment::Segment(uint32_t segment_id, uint64_t samplerate, unsigned int unit_size) :
  40         segment_id_(segment_id),
  41         sample_count_(0),
  42         start_time_(0),
  43         samplerate_(samplerate),
  44         unit_size_(unit_size),
  45         iterator_count_(0),
  46         mem_optimization_requested_(false),
  47         is_complete_(false)
  48 {
  49         lock_guard<recursive_mutex> lock(mutex_);
  50         assert(unit_size_ > 0);
  51
  52         // Determine the number of samples we can fit in one chunk
  53         // without exceeding MaxChunkSize
  54         chunk_size_ = min(MaxChunkSize, (MaxChunkSize / unit_size_) * unit_size_);
  55
  56         // Create the initial chunk
  57         current_chunk_ = new uint8_t[chunk_size_ + 7];  /* FIXME +7 is workaround for #1284 */
  58         data_chunks_.push_back(current_chunk_);
  59         used_samples_ = 0;
  60         unused_samples_ = chunk_size_ / unit_size_;
  61 }
  62
  63 Segment::~Segment()
  64 {
  65         lock_guard<recursive_mutex> lock(mutex_);
  66
  67         for (uint8_t* chunk : data_chunks_)
  68                 delete[] chunk;
  69 }
  70
  71 uint64_t Segment::get_sample_count() const
  72 {
  73         lock_guard<recursive_mutex> lock(mutex_);
  74         return sample_count_;
  75 }
  76
  77 const pv::util::Timestamp& Segment::start_time() const
  78 {
  79         return start_time_;
  80 }
  81
  82 double Segment::samplerate() const
  83 {
  84         return samplerate_;
  85 }
  86
  87 void Segment::set_samplerate(double samplerate)
  88 {
  89         samplerate_ = samplerate;
  90 }
  91
  92 unsigned int Segment::unit_size() const
  93 {
  94         return unit_size_;
  95 }
  96
  97 uint32_t Segment::segment_id() const
  98 {
  99         return segment_id_;
 100 }
 101
 102 void Segment::set_complete()
 103 {
 104         is_complete_ = true;
 105 }
 106
 107 bool Segment::is_complete() const
 108 {
 109         return is_complete_;
 110 }
 111
 112 void Segment::free_unused_memory()
 113 {
 114         lock_guard<recursive_mutex> lock(mutex_);
 115
 116         // Do not mess with the data chunks if we have iterators pointing at them
 117         if (iterator_count_ > 0) {
 118                 mem_optimization_requested_ = true;
 119                 return;
 120         }
 121
 122         if (current_chunk_) {
 123                 // No more data will come in, so re-create the last chunk accordingly
 124                 uint8_t* resized_chunk = new uint8_t[used_samples_ * unit_size_ + 7];  /* FIXME +7 is workaround for #1284 */
 125                 memcpy(resized_chunk, current_chunk_, used_samples_ * unit_size_);
 126
 127                 delete[] current_chunk_;
 128                 current_chunk_ = resized_chunk;
 129
 130                 data_chunks_.pop_back();
 131                 data_chunks_.push_back(resized_chunk);
 132         }
 133 }
 134
 135 void Segment::append_single_sample(void *data)
 136 {
 137         lock_guard<recursive_mutex> lock(mutex_);
 138
 139         // There will always be space for at least one sample in
 140         // the current chunk, so we do not need to test for space
 141
 142         memcpy(current_chunk_ + (used_samples_ * unit_size_), data, unit_size_);
 143         used_samples_++;
 144         unused_samples_--;
 145
 146         if (unused_samples_ == 0) {
 147                 current_chunk_ = new uint8_t[chunk_size_ + 7];  /* FIXME +7 is workaround for #1284 */
 148                 data_chunks_.push_back(current_chunk_);
 149                 used_samples_ = 0;
 150                 unused_samples_ = chunk_size_ / unit_size_;
 151         }
 152
 153         sample_count_++;
 154 }
 155
 156 void Segment::append_samples(void* data, uint64_t samples)
 157 {
 158         lock_guard<recursive_mutex> lock(mutex_);
 159
 160         const uint8_t* data_byte_ptr = (uint8_t*)data;
 161         uint64_t remaining_samples = samples;
 162         uint64_t data_offset = 0;
 163
 164         do {
 165                 uint64_t copy_count = 0;
 166
 167                 if (remaining_samples <= unused_samples_) {
 168                         // All samples fit into the current chunk
 169                         copy_count = remaining_samples;
 170                 } else {
 171                         // Only a part of the samples fit, fill up current chunk
 172                         copy_count = unused_samples_;
 173                 }
 174
 175                 const uint8_t* dest = &(current_chunk_[used_samples_ * unit_size_]);
 176                 const uint8_t* src = &(data_byte_ptr[data_offset]);
 177                 memcpy((void*)dest, (void*)src, (copy_count * unit_size_));
 178
 179                 used_samples_ += copy_count;
 180                 unused_samples_ -= copy_count;
 181                 remaining_samples -= copy_count;
 182                 data_offset += (copy_count * unit_size_);
 183
 184                 if (unused_samples_ == 0) {
 185                         try {
 186                                 // If we're out of memory, allocating a chunk will throw
 187                                 // std::bad_alloc. To give the application some usable memory
 188                                 // to work with in case chunk allocation fails, we allocate
 189                                 // extra memory and throw it away if it all succeeded.
 190                                 // This way, memory allocation will fail early enough to let
 191                                 // PV remain alive. Otherwise, PV will crash in a random
 192                                 // memory-allocating part of the application.
 193                                 current_chunk_ = new uint8_t[chunk_size_ + 7];  /* FIXME +7 is workaround for #1284 */
 194
 195                                 const int dummy_size = 2 * chunk_size_;
 196                                 auto dummy_chunk = new uint8_t[dummy_size];
 197                                 memset(dummy_chunk, 0xFF, dummy_size);
 198                                 delete[] dummy_chunk;
 199                         } catch (bad_alloc&) {
 200                                 delete[] current_chunk_;  // The new may have succeeded
 201                                 current_chunk_ = nullptr;
 202                                 throw;
 203                         }
 204
 205                         data_chunks_.push_back(current_chunk_);
 206                         used_samples_ = 0;
 207                         unused_samples_ = chunk_size_ / unit_size_;
 208                 }
 209         } while (remaining_samples > 0);
 210
 211         sample_count_ += samples;
 212 }
 213
 214 void Segment::get_raw_samples(uint64_t start, uint64_t count,
 215         uint8_t* dest) const
 216 {
 217         assert(start < sample_count_);
 218         assert(start + count <= sample_count_);
 219         assert(count > 0);
 220         assert(dest != nullptr);
 221
 222         lock_guard<recursive_mutex> lock(mutex_);
 223
 224         uint8_t* dest_ptr = dest;
 225
 226         uint64_t chunk_num = (start * unit_size_) / chunk_size_;
 227         uint64_t chunk_offs = (start * unit_size_) % chunk_size_;
 228
 229         while (count > 0) {
 230                 const uint8_t* chunk = data_chunks_[chunk_num];
 231
 232                 uint64_t copy_size = min(count * unit_size_,
 233                         chunk_size_ - chunk_offs);
 234
 235                 memcpy(dest_ptr, chunk + chunk_offs, copy_size);
 236
 237                 dest_ptr += copy_size;
 238                 count -= (copy_size / unit_size_);
 239
 240                 chunk_num++;
 241                 chunk_offs = 0;
 242         }
 243 }
 244
 245 SegmentDataIterator* Segment::begin_sample_iteration(uint64_t start)
 246 {
 247         SegmentDataIterator* it = new SegmentDataIterator;
 248
 249         assert(start < sample_count_);
 250
 251         iterator_count_++;
 252
 253         it->sample_index = start;
 254         it->chunk_num = (start * unit_size_) / chunk_size_;
 255         it->chunk_offs = (start * unit_size_) % chunk_size_;
 256         it->chunk = data_chunks_[it->chunk_num];
 257
 258         return it;
 259 }
 260
 261 void Segment::continue_sample_iteration(SegmentDataIterator* it, uint64_t increase)
 262 {
 263         it->sample_index += increase;
 264         it->chunk_offs += (increase * unit_size_);
 265
 266         if (it->chunk_offs > (chunk_size_ - 1)) {
 267                 it->chunk_num++;
 268                 it->chunk_offs -= chunk_size_;
 269                 it->chunk = data_chunks_[it->chunk_num];
 270         }
 271 }
 272
 273 void Segment::end_sample_iteration(SegmentDataIterator* it)
 274 {
 275         delete it;
 276
 277         iterator_count_--;
 278
 279         if ((iterator_count_ == 0) && mem_optimization_requested_) {
 280                 mem_optimization_requested_ = false;
 281                 free_unused_memory();
 282         }
 283 }
 284
 285 uint8_t* Segment::get_iterator_value(SegmentDataIterator* it)
 286 {
 287         assert(it->sample_index <= (sample_count_ - 1));
 288
 289         return (it->chunk + it->chunk_offs);
 290 }
 291
 292 uint64_t Segment::get_iterator_valid_length(SegmentDataIterator* it)
 293 {
 294         assert(it->sample_index <= (sample_count_ - 1));
 295
 296         return ((chunk_size_ - it->chunk_offs) / unit_size_);
 297 }
 298
 299 } // namespace data
 300 } // namespace pv