pv/data/analogsegment.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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <extdef.h>
  21
  22 #include <assert.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <cmath>
  26
  27 #include <algorithm>
  28
  29 #include "analogsegment.hpp"
  30
  31 using std::lock_guard;
  32 using std::recursive_mutex;
  33 using std::max;
  34 using std::max_element;
  35 using std::min;
  36 using std::min_element;
  37
  38 namespace pv {
  39 namespace data {
  40
  41 const int AnalogSegment::EnvelopeScalePower = 4;
  42 const int AnalogSegment::EnvelopeScaleFactor = 1 << EnvelopeScalePower;
  43 const float AnalogSegment::LogEnvelopeScaleFactor =
  44         logf(EnvelopeScaleFactor);
  45 const uint64_t AnalogSegment::EnvelopeDataUnit = 64*1024;       // bytes
  46
  47 AnalogSegment::AnalogSegment(
  48         uint64_t samplerate, const uint64_t expected_num_samples) :
  49         Segment(samplerate, sizeof(float))
  50 {
  51         set_capacity(expected_num_samples);
  52
  53         lock_guard<recursive_mutex> lock(mutex_);
  54         memset(envelope_levels_, 0, sizeof(envelope_levels_));
  55 }
  56
  57 AnalogSegment::~AnalogSegment()
  58 {
  59         lock_guard<recursive_mutex> lock(mutex_);
  60         for (Envelope &e : envelope_levels_)
  61                 free(e.samples);
  62 }
  63
  64 void AnalogSegment::append_interleaved_samples(const float *data,
  65         size_t sample_count, size_t stride)
  66 {
  67         assert(unit_size_ == sizeof(float));
  68
  69         lock_guard<recursive_mutex> lock(mutex_);
  70
  71         // If we're out of memory, this will throw std::bad_alloc
  72         data_.resize((sample_count_ + sample_count) * sizeof(float));
  73
  74         float *dst = (float*)data_.data() + sample_count_;
  75         const float *dst_end = dst + sample_count;
  76         while (dst != dst_end) {
  77                 *dst++ = *data;
  78                 data += stride;
  79         }
  80
  81         sample_count_ += sample_count;
  82
  83         // Generate the first mip-map from the data
  84         append_payload_to_envelope_levels();
  85 }
  86
  87 const float* AnalogSegment::get_samples(
  88         int64_t start_sample, int64_t end_sample) const
  89 {
  90         assert(start_sample >= 0);
  91         assert(start_sample < (int64_t)sample_count_);
  92         assert(end_sample >= 0);
  93         assert(end_sample < (int64_t)sample_count_);
  94         assert(start_sample <= end_sample);
  95
  96         lock_guard<recursive_mutex> lock(mutex_);
  97
  98         float *const data = new float[end_sample - start_sample];
  99         memcpy(data, (float*)data_.data() + start_sample, sizeof(float) *
 100                 (end_sample - start_sample));
 101         return data;
 102 }
 103
 104 void AnalogSegment::get_envelope_section(EnvelopeSection &s,
 105         uint64_t start, uint64_t end, float min_length) const
 106 {
 107         assert(end <= get_sample_count());
 108         assert(start <= end);
 109         assert(min_length > 0);
 110
 111         lock_guard<recursive_mutex> lock(mutex_);
 112
 113         const unsigned int min_level = max((int)floorf(logf(min_length) /
 114                 LogEnvelopeScaleFactor) - 1, 0);
 115         const unsigned int scale_power = (min_level + 1) *
 116                 EnvelopeScalePower;
 117         start >>= scale_power;
 118         end >>= scale_power;
 119
 120         s.start = start << scale_power;
 121         s.scale = 1 << scale_power;
 122         s.length = end - start;
 123         s.samples = new EnvelopeSample[s.length];
 124         memcpy(s.samples, envelope_levels_[min_level].samples + start,
 125                 s.length * sizeof(EnvelopeSample));
 126 }
 127
 128 void AnalogSegment::reallocate_envelope(Envelope &e)
 129 {
 130         const uint64_t new_data_length = ((e.length + EnvelopeDataUnit - 1) /
 131                 EnvelopeDataUnit) * EnvelopeDataUnit;
 132         if (new_data_length > e.data_length) {
 133                 e.data_length = new_data_length;
 134                 e.samples = (EnvelopeSample*)realloc(e.samples,
 135                         new_data_length * sizeof(EnvelopeSample));
 136         }
 137 }
 138
 139 void AnalogSegment::append_payload_to_envelope_levels()
 140 {
 141         Envelope &e0 = envelope_levels_[0];
 142         uint64_t prev_length;
 143         EnvelopeSample *dest_ptr;
 144
 145         // Expand the data buffer to fit the new samples
 146         prev_length = e0.length;
 147         e0.length = sample_count_ / EnvelopeScaleFactor;
 148
 149         // Break off if there are no new samples to compute
 150         if (e0.length == prev_length)
 151                 return;
 152
 153         reallocate_envelope(e0);
 154
 155         dest_ptr = e0.samples + prev_length;
 156
 157         // Iterate through the samples to populate the first level mipmap
 158         const float *const end_src_ptr = (float*)data_.data() +
 159                 e0.length * EnvelopeScaleFactor;
 160         for (const float *src_ptr = (float*)data_.data() +
 161                         prev_length * EnvelopeScaleFactor;
 162                         src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor) {
 163                 const EnvelopeSample sub_sample = {
 164                         *min_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 165                         *max_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 166                 };
 167
 168                 *dest_ptr++ = sub_sample;
 169         }
 170
 171         // Compute higher level mipmaps
 172         for (unsigned int level = 1; level < ScaleStepCount; level++) {
 173                 Envelope &e = envelope_levels_[level];
 174                 const Envelope &el = envelope_levels_[level-1];
 175
 176                 // Expand the data buffer to fit the new samples
 177                 prev_length = e.length;
 178                 e.length = el.length / EnvelopeScaleFactor;
 179
 180                 // Break off if there are no more samples to computed
 181                 if (e.length == prev_length)
 182                         break;
 183
 184                 reallocate_envelope(e);
 185
 186                 // Subsample the level lower level
 187                 const EnvelopeSample *src_ptr =
 188                         el.samples + prev_length * EnvelopeScaleFactor;
 189                 const EnvelopeSample *const end_dest_ptr = e.samples + e.length;
 190                 for (dest_ptr = e.samples + prev_length;
 191                                 dest_ptr < end_dest_ptr; dest_ptr++) {
 192                         const EnvelopeSample *const end_src_ptr =
 193                                 src_ptr + EnvelopeScaleFactor;
 194
 195                         EnvelopeSample sub_sample = *src_ptr++;
 196                         while (src_ptr < end_src_ptr) {
 197                                 sub_sample.min = min(sub_sample.min, src_ptr->min);
 198                                 sub_sample.max = max(sub_sample.max, src_ptr->max);
 199                                 src_ptr++;
 200                         }
 201
 202                         *dest_ptr = sub_sample;
 203                 }
 204         }
 205 }
 206
 207 } // namespace data
 208 } // namespace pv