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 <assert.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include <vector>
  28
  29 using std::lock_guard;
  30 using std::recursive_mutex;
  31 using std::vector;
  32
  33 namespace pv {
  34 namespace data {
  35
  36 Segment::Segment(uint64_t samplerate, unsigned int unit_size) :
  37         sample_count_(0),
  38         start_time_(0),
  39         samplerate_(samplerate),
  40         unit_size_(unit_size)
  41 {
  42         lock_guard<recursive_mutex> lock(mutex_);
  43         assert(unit_size_ > 0);
  44
  45         // Determine the number of samples we can fit in one chunk
  46         // without exceeding MaxChunkSize
  47         chunk_size_ = std::min(MaxChunkSize,
  48                 (MaxChunkSize / unit_size_) * unit_size_);
  49
  50         // Create the initial chunk
  51         current_chunk_ = new uint8_t[chunk_size_];
  52         data_chunks_.push_back(current_chunk_);
  53         used_samples_ = 0;
  54         unused_samples_ = chunk_size_ / unit_size_;
  55 }
  56
  57 Segment::~Segment()
  58 {
  59         lock_guard<recursive_mutex> lock(mutex_);
  60
  61         for (uint8_t* chunk : data_chunks_)
  62                 delete[] chunk;
  63 }
  64
  65 uint64_t Segment::get_sample_count() const
  66 {
  67         lock_guard<recursive_mutex> lock(mutex_);
  68         return sample_count_;
  69 }
  70
  71 const pv::util::Timestamp& Segment::start_time() const
  72 {
  73         return start_time_;
  74 }
  75
  76 double Segment::samplerate() const
  77 {
  78         return samplerate_;
  79 }
  80
  81 void Segment::set_samplerate(double samplerate)
  82 {
  83         samplerate_ = samplerate;
  84 }
  85
  86 unsigned int Segment::unit_size() const
  87 {
  88         return unit_size_;
  89 }
  90
  91 void Segment::free_unused_memory()
  92 {
  93         lock_guard<recursive_mutex> lock(mutex_);
  94
  95         // No more data will come in, so re-create the last chunk accordingly
  96         uint8_t* resized_chunk = new uint8_t[used_samples_ * unit_size_];
  97         memcpy(resized_chunk, current_chunk_, used_samples_ * unit_size_);
  98
  99         delete[] current_chunk_;
 100         current_chunk_ = resized_chunk;
 101
 102         data_chunks_.pop_back();
 103         data_chunks_.push_back(resized_chunk);
 104 }
 105
 106 void Segment::append_single_sample(void *data)
 107 {
 108         lock_guard<recursive_mutex> lock(mutex_);
 109
 110         // There will always be space for at least one sample in
 111         // the current chunk, so we do not need to test for space
 112
 113         memcpy(current_chunk_ + (used_samples_ * unit_size_),
 114                 data, unit_size_);
 115         used_samples_++;
 116         unused_samples_--;
 117
 118         if (unused_samples_ == 0) {
 119                 current_chunk_ = new uint8_t[chunk_size_];
 120                 data_chunks_.push_back(current_chunk_);
 121                 used_samples_ = 0;
 122                 unused_samples_ = chunk_size_ / unit_size_;
 123         }
 124
 125         sample_count_++;
 126 }
 127
 128 void Segment::append_samples(void* data, uint64_t samples)
 129 {
 130         lock_guard<recursive_mutex> lock(mutex_);
 131
 132         if (unused_samples_ >= samples) {
 133                 // All samples fit into the current chunk
 134                 memcpy(current_chunk_ + (used_samples_ * unit_size_),
 135                         data, (samples * unit_size_));
 136                 used_samples_ += samples;
 137                 unused_samples_ -= samples;
 138         } else {
 139                 // Only a part of the samples fit, split data up between chunks
 140                 memcpy(current_chunk_ + (used_samples_ * unit_size_),
 141                         data, (unused_samples_ * unit_size_));
 142                 const uint64_t remaining_samples = samples - unused_samples_;
 143
 144                 // If we're out of memory, this will throw std::bad_alloc
 145                 current_chunk_ = new uint8_t[chunk_size_];
 146                 data_chunks_.push_back(current_chunk_);
 147                 memcpy(current_chunk_, (uint8_t*)data + (unused_samples_ * unit_size_),
 148                         (remaining_samples * unit_size_));
 149
 150                 used_samples_ = remaining_samples;
 151                 unused_samples_ = (chunk_size_ / unit_size_) - remaining_samples;
 152         }
 153
 154         if (unused_samples_ == 0) {
 155                 // If we're out of memory, this will throw std::bad_alloc
 156                 current_chunk_ = new uint8_t[chunk_size_];
 157                 data_chunks_.push_back(current_chunk_);
 158                 used_samples_ = 0;
 159                 unused_samples_ = chunk_size_ / unit_size_;
 160         }
 161
 162         sample_count_ += samples;
 163 }
 164
 165 uint8_t* Segment::get_raw_samples(uint64_t start, uint64_t count) const
 166 {
 167         assert(start < sample_count_);
 168         assert(start + count <= sample_count_);
 169         assert(count > 0);
 170
 171         lock_guard<recursive_mutex> lock(mutex_);
 172
 173         uint8_t* dest = new uint8_t[count * unit_size_];
 174         uint8_t* dest_ptr = dest;
 175
 176         uint64_t chunk_num = (start * unit_size_) / chunk_size_;
 177         uint64_t chunk_offs = (start * unit_size_) % chunk_size_;
 178
 179         while (count > 0) {
 180                 const uint8_t* chunk = data_chunks_[chunk_num];
 181
 182                 uint64_t copy_size = std::min(count * unit_size_,
 183                         chunk_size_ - chunk_offs);
 184
 185                 memcpy(dest_ptr, chunk + chunk_offs, copy_size);
 186
 187                 dest_ptr += copy_size;
 188                 count -= (copy_size / unit_size_);
 189
 190                 chunk_num++;
 191                 chunk_offs = 0;
 192         }
 193
 194         return dest;
 195 }
 196
 197 SegmentRawDataIterator* Segment::begin_raw_sample_iteration(uint64_t start) const
 198 {
 199         SegmentRawDataIterator* it = new SegmentRawDataIterator;
 200
 201         assert(start < sample_count_);
 202
 203         it->sample_index = start;
 204         it->chunk_num = (start * unit_size_) / chunk_size_;
 205         it->chunk_offs = (start * unit_size_) % chunk_size_;
 206         it->chunk = data_chunks_[it->chunk_num];
 207         it->value = it->chunk + it->chunk_offs;
 208
 209         return it;
 210 }
 211
 212 void Segment::continue_raw_sample_iteration(SegmentRawDataIterator* it, uint64_t increase) const
 213 {
 214         lock_guard<recursive_mutex> lock(mutex_);
 215
 216         if (it->sample_index > sample_count_)
 217         {
 218                 // Fail gracefully if we are asked to deliver data we don't have
 219                 return;
 220         } else {
 221                 it->sample_index += increase;
 222                 it->chunk_offs += (increase * unit_size_);
 223         }
 224
 225         if (it->chunk_offs > (chunk_size_ - 1)) {
 226                 it->chunk_num++;
 227                 it->chunk_offs -= chunk_size_;
 228                 it->chunk = data_chunks_[it->chunk_num];
 229         }
 230
 231         it->value = it->chunk + it->chunk_offs;
 232 }
 233
 234 void Segment::end_raw_sample_iteration(SegmentRawDataIterator* it) const
 235 {
 236         delete it;
 237 }
 238
 239
 240 } // namespace data
 241 } // namespace pv