2 * This file is part of the PulseView project.
4 * Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
5 * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
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.
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.
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/>.
21 #include "segment.hpp"
28 using std::lock_guard;
30 using std::recursive_mutex;
35 const uint64_t Segment::MaxChunkSize = 10 * 1024 * 1024; /* 10MiB */
37 Segment::Segment(uint32_t segment_id, uint64_t samplerate, unsigned int unit_size) :
38 segment_id_(segment_id),
41 samplerate_(samplerate),
42 unit_size_(unit_size),
44 mem_optimization_requested_(false),
47 lock_guard<recursive_mutex> lock(mutex_);
48 assert(unit_size_ > 0);
50 // Determine the number of samples we can fit in one chunk
51 // without exceeding MaxChunkSize
52 chunk_size_ = min(MaxChunkSize, (MaxChunkSize / unit_size_) * unit_size_);
54 // Create the initial chunk
55 current_chunk_ = new uint8_t[chunk_size_];
56 data_chunks_.push_back(current_chunk_);
58 unused_samples_ = chunk_size_ / unit_size_;
63 lock_guard<recursive_mutex> lock(mutex_);
65 for (uint8_t* chunk : data_chunks_)
69 uint64_t Segment::get_sample_count() const
71 lock_guard<recursive_mutex> lock(mutex_);
75 const pv::util::Timestamp& Segment::start_time() const
80 double Segment::samplerate() const
85 void Segment::set_samplerate(double samplerate)
87 samplerate_ = samplerate;
90 unsigned int Segment::unit_size() const
95 uint32_t Segment::segment_id() const
100 void Segment::set_complete()
105 bool Segment::is_complete() const
110 void Segment::free_unused_memory()
112 lock_guard<recursive_mutex> lock(mutex_);
114 // Do not mess with the data chunks if we have iterators pointing at them
115 if (iterator_count_ > 0) {
116 mem_optimization_requested_ = true;
120 if (current_chunk_) {
121 // No more data will come in, so re-create the last chunk accordingly
122 uint8_t* resized_chunk = new uint8_t[used_samples_ * unit_size_];
123 memcpy(resized_chunk, current_chunk_, used_samples_ * unit_size_);
125 delete[] current_chunk_;
126 current_chunk_ = resized_chunk;
128 data_chunks_.pop_back();
129 data_chunks_.push_back(resized_chunk);
133 void Segment::append_single_sample(void *data)
135 lock_guard<recursive_mutex> lock(mutex_);
137 // There will always be space for at least one sample in
138 // the current chunk, so we do not need to test for space
140 memcpy(current_chunk_ + (used_samples_ * unit_size_), data, unit_size_);
144 if (unused_samples_ == 0) {
145 current_chunk_ = new uint8_t[chunk_size_];
146 data_chunks_.push_back(current_chunk_);
148 unused_samples_ = chunk_size_ / unit_size_;
154 void Segment::append_samples(void* data, uint64_t samples)
156 lock_guard<recursive_mutex> lock(mutex_);
158 const uint8_t* data_byte_ptr = (uint8_t*)data;
159 uint64_t remaining_samples = samples;
160 uint64_t data_offset = 0;
163 uint64_t copy_count = 0;
165 if (remaining_samples <= unused_samples_) {
166 // All samples fit into the current chunk
167 copy_count = remaining_samples;
169 // Only a part of the samples fit, fill up current chunk
170 copy_count = unused_samples_;
173 const uint8_t* dest = &(current_chunk_[used_samples_ * unit_size_]);
174 const uint8_t* src = &(data_byte_ptr[data_offset]);
175 memcpy((void*)dest, (void*)src, (copy_count * unit_size_));
177 used_samples_ += copy_count;
178 unused_samples_ -= copy_count;
179 remaining_samples -= copy_count;
180 data_offset += (copy_count * unit_size_);
182 if (unused_samples_ == 0) {
184 // If we're out of memory, allocating a chunk will throw
185 // std::bad_alloc. To give the application some usable memory
186 // to work with in case chunk allocation fails, we allocate
187 // extra memory and throw it away if it all succeeded.
188 // This way, memory allocation will fail early enough to let
189 // PV remain alive. Otherwise, PV will crash in a random
190 // memory-allocating part of the application.
191 current_chunk_ = new uint8_t[chunk_size_];
193 const int dummy_size = 2 * chunk_size_;
194 auto dummy_chunk = new uint8_t[dummy_size];
195 memset(dummy_chunk, 0xFF, dummy_size);
196 delete[] dummy_chunk;
197 } catch (bad_alloc) {
198 delete[] current_chunk_; // The new may have succeeded
199 current_chunk_ = nullptr;
203 data_chunks_.push_back(current_chunk_);
205 unused_samples_ = chunk_size_ / unit_size_;
207 } while (remaining_samples > 0);
209 sample_count_ += samples;
212 void Segment::get_raw_samples(uint64_t start, uint64_t count,
215 assert(start < sample_count_);
216 assert(start + count <= sample_count_);
218 assert(dest != nullptr);
220 lock_guard<recursive_mutex> lock(mutex_);
222 uint8_t* dest_ptr = dest;
224 uint64_t chunk_num = (start * unit_size_) / chunk_size_;
225 uint64_t chunk_offs = (start * unit_size_) % chunk_size_;
228 const uint8_t* chunk = data_chunks_[chunk_num];
230 uint64_t copy_size = min(count * unit_size_,
231 chunk_size_ - chunk_offs);
233 memcpy(dest_ptr, chunk + chunk_offs, copy_size);
235 dest_ptr += copy_size;
236 count -= (copy_size / unit_size_);
243 SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start)
245 SegmentRawDataIterator* it = new SegmentRawDataIterator;
247 assert(start < sample_count_);
251 it->sample_index = start;
252 it->chunk_num = (start * unit_size_) / chunk_size_;
253 it->chunk_offs = (start * unit_size_) % chunk_size_;
254 it->chunk = data_chunks_[it->chunk_num];
255 it->value = it->chunk + it->chunk_offs;
260 void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t increase)
262 // Fail gracefully if we are asked to deliver data we don't have
263 if (it->sample_index > sample_count_)
266 it->sample_index += increase;
267 it->chunk_offs += (increase * unit_size_);
269 if (it->chunk_offs > (chunk_size_ - 1)) {
271 it->chunk_offs -= chunk_size_;
272 it->chunk = data_chunks_[it->chunk_num];
275 it->value = it->chunk + it->chunk_offs;
278 void Segment::end_raw_sample_iteration(SegmentRawDataIterator* it)
284 if ((iterator_count_ == 0) && mem_optimization_requested_) {
285 mem_optimization_requested_ = false;
286 free_unused_memory();