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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <extdef.h>
  22
  23 #include <assert.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <cmath>
  27
  28 #include <algorithm>
  29
  30 #include "analogsegment.hpp"
  31
  32 using std::lock_guard;
  33 using std::recursive_mutex;
  34 using std::max;
  35 using std::max_element;
  36 using std::min;
  37 using std::min_element;
  38
  39 namespace pv {
  40 namespace data {
  41
  42 const int AnalogSegment::EnvelopeScalePower = 4;
  43 const int AnalogSegment::EnvelopeScaleFactor = 1 << EnvelopeScalePower;
  44 const float AnalogSegment::LogEnvelopeScaleFactor =
  45         logf(EnvelopeScaleFactor);
  46 const uint64_t AnalogSegment::EnvelopeDataUnit = 64*1024;       // bytes
  47
  48 AnalogSegment::AnalogSegment(
  49         uint64_t samplerate, const uint64_t expected_num_samples) :
  50         Segment(samplerate, sizeof(float))
  51 {
  52         set_capacity(expected_num_samples);
  53
  54         lock_guard<recursive_mutex> lock(mutex_);
  55         memset(envelope_levels_, 0, sizeof(envelope_levels_));
  56 }
  57
  58 AnalogSegment::~AnalogSegment()
  59 {
  60         lock_guard<recursive_mutex> lock(mutex_);
  61         for (Envelope &e : envelope_levels_)
  62                 free(e.samples);
  63 }
  64
  65 void AnalogSegment::append_interleaved_samples(const float *data,
  66         size_t sample_count, size_t stride)
  67 {
  68         assert(unit_size_ == sizeof(float));
  69
  70         lock_guard<recursive_mutex> lock(mutex_);
  71
  72         // If we're out of memory, this will throw std::bad_alloc
  73         data_.resize((sample_count_ + sample_count) * sizeof(float));
  74
  75         float *dst = (float*)data_.data() + sample_count_;
  76         const float *dst_end = dst + sample_count;
  77         while (dst != dst_end) {
  78                 *dst++ = *data;
  79                 data += stride;
  80         }
  81
  82         sample_count_ += sample_count;
  83
  84         // Generate the first mip-map from the data
  85         append_payload_to_envelope_levels();
  86 }
  87
  88 const float* AnalogSegment::get_samples(
  89         int64_t start_sample, int64_t end_sample) const
  90 {
  91         assert(start_sample >= 0);
  92         assert(start_sample < (int64_t)sample_count_);
  93         assert(end_sample >= 0);
  94         assert(end_sample < (int64_t)sample_count_);
  95         assert(start_sample <= end_sample);
  96
  97         lock_guard<recursive_mutex> lock(mutex_);
  98
  99         float *const data = new float[end_sample - start_sample];
 100         memcpy(data, (float*)data_.data() + start_sample, sizeof(float) *
 101                 (end_sample - start_sample));
 102         return data;
 103 }
 104
 105 void AnalogSegment::get_envelope_section(EnvelopeSection &s,
 106         uint64_t start, uint64_t end, float min_length) const
 107 {
 108         assert(end <= get_sample_count());
 109         assert(start <= end);
 110         assert(min_length > 0);
 111
 112         lock_guard<recursive_mutex> lock(mutex_);
 113
 114         const unsigned int min_level = max((int)floorf(logf(min_length) /
 115                 LogEnvelopeScaleFactor) - 1, 0);
 116         const unsigned int scale_power = (min_level + 1) *
 117                 EnvelopeScalePower;
 118         start >>= scale_power;
 119         end >>= scale_power;
 120
 121         s.start = start << scale_power;
 122         s.scale = 1 << scale_power;
 123         s.length = end - start;
 124         s.samples = new EnvelopeSample[s.length];
 125         memcpy(s.samples, envelope_levels_[min_level].samples + start,
 126                 s.length * sizeof(EnvelopeSample));
 127 }
 128
 129 void AnalogSegment::reallocate_envelope(Envelope &e)
 130 {
 131         const uint64_t new_data_length = ((e.length + EnvelopeDataUnit - 1) /
 132                 EnvelopeDataUnit) * EnvelopeDataUnit;
 133         if (new_data_length > e.data_length) {
 134                 e.data_length = new_data_length;
 135                 e.samples = (EnvelopeSample*)realloc(e.samples,
 136                         new_data_length * sizeof(EnvelopeSample));
 137         }
 138 }
 139
 140 void AnalogSegment::append_payload_to_envelope_levels()
 141 {
 142         Envelope &e0 = envelope_levels_[0];
 143         uint64_t prev_length;
 144         EnvelopeSample *dest_ptr;
 145
 146         // Expand the data buffer to fit the new samples
 147         prev_length = e0.length;
 148         e0.length = sample_count_ / EnvelopeScaleFactor;
 149
 150         // Break off if there are no new samples to compute
 151         if (e0.length == prev_length)
 152                 return;
 153
 154         reallocate_envelope(e0);
 155
 156         dest_ptr = e0.samples + prev_length;
 157
 158         // Iterate through the samples to populate the first level mipmap
 159         const float *const end_src_ptr = (float*)data_.data() +
 160                 e0.length * EnvelopeScaleFactor;
 161         for (const float *src_ptr = (float*)data_.data() +
 162                         prev_length * EnvelopeScaleFactor;
 163                         src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor) {
 164                 const EnvelopeSample sub_sample = {
 165                         *min_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 166                         *max_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 167                 };
 168
 169                 *dest_ptr++ = sub_sample;
 170         }
 171
 172         // Compute higher level mipmaps
 173         for (unsigned int level = 1; level < ScaleStepCount; level++) {
 174                 Envelope &e = envelope_levels_[level];
 175                 const Envelope &el = envelope_levels_[level-1];
 176
 177                 // Expand the data buffer to fit the new samples
 178                 prev_length = e.length;
 179                 e.length = el.length / EnvelopeScaleFactor;
 180
 181                 // Break off if there are no more samples to computed
 182                 if (e.length == prev_length)
 183                         break;
 184
 185                 reallocate_envelope(e);
 186
 187                 // Subsample the level lower level
 188                 const EnvelopeSample *src_ptr =
 189                         el.samples + prev_length * EnvelopeScaleFactor;
 190                 const EnvelopeSample *const end_dest_ptr = e.samples + e.length;
 191                 for (dest_ptr = e.samples + prev_length;
 192                                 dest_ptr < end_dest_ptr; dest_ptr++) {
 193                         const EnvelopeSample *const end_src_ptr =
 194                                 src_ptr + EnvelopeScaleFactor;
 195
 196                         EnvelopeSample sub_sample = *src_ptr++;
 197                         while (src_ptr < end_src_ptr) {
 198                                 sub_sample.min = min(sub_sample.min, src_ptr->min);
 199                                 sub_sample.max = max(sub_sample.max, src_ptr->max);
 200                                 src_ptr++;
 201                         }
 202
 203                         *dest_ptr = sub_sample;
 204                 }
 205         }
 206 }
 207
 208 } // namespace data
 209 } // namespace pv