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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 | using std::bad_alloc; | |
28 | using std::lock_guard; | |
29 | using std::min; | |
30 | using std::recursive_mutex; | |
31 | ||
32 | namespace pv { | |
33 | namespace data { | |
34 | ||
35 | const uint64_t Segment::MaxChunkSize = 10 * 1024 * 1024; /* 10MiB */ | |
36 | ||
37 | Segment::Segment(uint32_t segment_id, uint64_t samplerate, unsigned int unit_size) : | |
38 | segment_id_(segment_id), | |
39 | sample_count_(0), | |
40 | start_time_(0), | |
41 | samplerate_(samplerate), | |
42 | unit_size_(unit_size), | |
43 | iterator_count_(0), | |
44 | mem_optimization_requested_(false), | |
45 | is_complete_(false) | |
46 | { | |
47 | lock_guard<recursive_mutex> lock(mutex_); | |
48 | assert(unit_size_ > 0); | |
49 | ||
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_); | |
53 | ||
54 | // Create the initial chunk | |
55 | current_chunk_ = new uint8_t[chunk_size_]; | |
56 | data_chunks_.push_back(current_chunk_); | |
57 | used_samples_ = 0; | |
58 | unused_samples_ = chunk_size_ / unit_size_; | |
59 | } | |
60 | ||
61 | Segment::~Segment() | |
62 | { | |
63 | lock_guard<recursive_mutex> lock(mutex_); | |
64 | ||
65 | for (uint8_t* chunk : data_chunks_) | |
66 | delete[] chunk; | |
67 | } | |
68 | ||
69 | uint64_t Segment::get_sample_count() const | |
70 | { | |
71 | lock_guard<recursive_mutex> lock(mutex_); | |
72 | return sample_count_; | |
73 | } | |
74 | ||
75 | const pv::util::Timestamp& Segment::start_time() const | |
76 | { | |
77 | return start_time_; | |
78 | } | |
79 | ||
80 | double Segment::samplerate() const | |
81 | { | |
82 | return samplerate_; | |
83 | } | |
84 | ||
85 | void Segment::set_samplerate(double samplerate) | |
86 | { | |
87 | samplerate_ = samplerate; | |
88 | } | |
89 | ||
90 | unsigned int Segment::unit_size() const | |
91 | { | |
92 | return unit_size_; | |
93 | } | |
94 | ||
95 | uint32_t Segment::segment_id() const | |
96 | { | |
97 | return segment_id_; | |
98 | } | |
99 | ||
100 | void Segment::set_complete() | |
101 | { | |
102 | is_complete_ = true; | |
103 | } | |
104 | ||
105 | bool Segment::is_complete() const | |
106 | { | |
107 | return is_complete_; | |
108 | } | |
109 | ||
110 | void Segment::free_unused_memory() | |
111 | { | |
112 | lock_guard<recursive_mutex> lock(mutex_); | |
113 | ||
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; | |
117 | return; | |
118 | } | |
119 | ||
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_); | |
124 | ||
125 | delete[] current_chunk_; | |
126 | current_chunk_ = resized_chunk; | |
127 | ||
128 | data_chunks_.pop_back(); | |
129 | data_chunks_.push_back(resized_chunk); | |
130 | } | |
131 | } | |
132 | ||
133 | void Segment::append_single_sample(void *data) | |
134 | { | |
135 | lock_guard<recursive_mutex> lock(mutex_); | |
136 | ||
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 | |
139 | ||
140 | memcpy(current_chunk_ + (used_samples_ * unit_size_), data, unit_size_); | |
141 | used_samples_++; | |
142 | unused_samples_--; | |
143 | ||
144 | if (unused_samples_ == 0) { | |
145 | current_chunk_ = new uint8_t[chunk_size_]; | |
146 | data_chunks_.push_back(current_chunk_); | |
147 | used_samples_ = 0; | |
148 | unused_samples_ = chunk_size_ / unit_size_; | |
149 | } | |
150 | ||
151 | sample_count_++; | |
152 | } | |
153 | ||
154 | void Segment::append_samples(void* data, uint64_t samples) | |
155 | { | |
156 | lock_guard<recursive_mutex> lock(mutex_); | |
157 | ||
158 | const uint8_t* data_byte_ptr = (uint8_t*)data; | |
159 | uint64_t remaining_samples = samples; | |
160 | uint64_t data_offset = 0; | |
161 | ||
162 | do { | |
163 | uint64_t copy_count = 0; | |
164 | ||
165 | if (remaining_samples <= unused_samples_) { | |
166 | // All samples fit into the current chunk | |
167 | copy_count = remaining_samples; | |
168 | } else { | |
169 | // Only a part of the samples fit, fill up current chunk | |
170 | copy_count = unused_samples_; | |
171 | } | |
172 | ||
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_)); | |
176 | ||
177 | used_samples_ += copy_count; | |
178 | unused_samples_ -= copy_count; | |
179 | remaining_samples -= copy_count; | |
180 | data_offset += (copy_count * unit_size_); | |
181 | ||
182 | if (unused_samples_ == 0) { | |
183 | try { | |
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_]; | |
192 | ||
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; | |
200 | throw; | |
201 | } | |
202 | ||
203 | data_chunks_.push_back(current_chunk_); | |
204 | used_samples_ = 0; | |
205 | unused_samples_ = chunk_size_ / unit_size_; | |
206 | } | |
207 | } while (remaining_samples > 0); | |
208 | ||
209 | sample_count_ += samples; | |
210 | } | |
211 | ||
212 | void Segment::get_raw_samples(uint64_t start, uint64_t count, | |
213 | uint8_t* dest) const | |
214 | { | |
215 | assert(start < sample_count_); | |
216 | assert(start + count <= sample_count_); | |
217 | assert(count > 0); | |
218 | assert(dest != nullptr); | |
219 | ||
220 | lock_guard<recursive_mutex> lock(mutex_); | |
221 | ||
222 | uint8_t* dest_ptr = dest; | |
223 | ||
224 | uint64_t chunk_num = (start * unit_size_) / chunk_size_; | |
225 | uint64_t chunk_offs = (start * unit_size_) % chunk_size_; | |
226 | ||
227 | while (count > 0) { | |
228 | const uint8_t* chunk = data_chunks_[chunk_num]; | |
229 | ||
230 | uint64_t copy_size = min(count * unit_size_, | |
231 | chunk_size_ - chunk_offs); | |
232 | ||
233 | memcpy(dest_ptr, chunk + chunk_offs, copy_size); | |
234 | ||
235 | dest_ptr += copy_size; | |
236 | count -= (copy_size / unit_size_); | |
237 | ||
238 | chunk_num++; | |
239 | chunk_offs = 0; | |
240 | } | |
241 | } | |
242 | ||
243 | SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start) | |
244 | { | |
245 | SegmentRawDataIterator* it = new SegmentRawDataIterator; | |
246 | ||
247 | assert(start < sample_count_); | |
248 | ||
249 | iterator_count_++; | |
250 | ||
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; | |
256 | ||
257 | return it; | |
258 | } | |
259 | ||
260 | void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t increase) | |
261 | { | |
262 | // Fail gracefully if we are asked to deliver data we don't have | |
263 | if (it->sample_index > sample_count_) | |
264 | return; | |
265 | ||
266 | it->sample_index += increase; | |
267 | it->chunk_offs += (increase * unit_size_); | |
268 | ||
269 | if (it->chunk_offs > (chunk_size_ - 1)) { | |
270 | it->chunk_num++; | |
271 | it->chunk_offs -= chunk_size_; | |
272 | it->chunk = data_chunks_[it->chunk_num]; | |
273 | } | |
274 | ||
275 | it->value = it->chunk + it->chunk_offs; | |
276 | } | |
277 | ||
278 | void Segment::end_raw_sample_iteration(SegmentRawDataIterator* it) | |
279 | { | |
280 | delete it; | |
281 | ||
282 | iterator_count_--; | |
283 | ||
284 | if ((iterator_count_ == 0) && mem_optimization_requested_) { | |
285 | mem_optimization_requested_ = false; | |
286 | free_unused_memory(); | |
287 | } | |
288 | } | |
289 | ||
290 | } // namespace data | |
291 | } // namespace pv |