pv/data/analogsnapshot.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 <math.h>
  27
  28 #include <algorithm>
  29
  30 #include <boost/foreach.hpp>
  31
  32 #include "analogsnapshot.h"
  33
  34 using boost::lock_guard;
  35 using boost::recursive_mutex;
  36 using std::max;
  37 using std::max_element;
  38 using std::min;
  39 using std::min_element;
  40
  41 namespace pv {
  42 namespace data {
  43
  44 const int AnalogSnapshot::EnvelopeScalePower = 4;
  45 const int AnalogSnapshot::EnvelopeScaleFactor = 1 << EnvelopeScalePower;
  46 const float AnalogSnapshot::LogEnvelopeScaleFactor =
  47         logf(EnvelopeScaleFactor);
  48 const uint64_t AnalogSnapshot::EnvelopeDataUnit = 64*1024;      // bytes
  49
  50 AnalogSnapshot::AnalogSnapshot() :
  51         Snapshot(sizeof(float))
  52 {
  53         lock_guard<recursive_mutex> lock(_mutex);
  54         memset(_envelope_levels, 0, sizeof(_envelope_levels));
  55 }
  56
  57 AnalogSnapshot::~AnalogSnapshot()
  58 {
  59         lock_guard<recursive_mutex> lock(_mutex);
  60         BOOST_FOREACH(Envelope &e, _envelope_levels)
  61                 free(e.samples);
  62 }
  63
  64 void AnalogSnapshot::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         _data = realloc(_data, (_sample_count + sample_count) * sizeof(float));
  72
  73         float *dst = (float*)_data + _sample_count;
  74         const float *dst_end = dst + sample_count;
  75         while (dst != dst_end)
  76         {
  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* AnalogSnapshot::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 + start_sample, sizeof(float) *
 100                 (end_sample - start_sample));
 101         return data;
 102 }
 103
 104 void AnalogSnapshot::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 AnalogSnapshot::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         {
 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 AnalogSnapshot::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 +
 160                 e0.length * EnvelopeScaleFactor;
 161         for (const float *src_ptr = (float*)_data +
 162                 prev_length * EnvelopeScaleFactor;
 163                 src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor)
 164         {
 165                 const EnvelopeSample sub_sample = {
 166                         *min_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 167                         *max_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 168                 };
 169
 170                 *dest_ptr++ = sub_sample;
 171         }
 172
 173         // Compute higher level mipmaps
 174         for (unsigned int level = 1; level < ScaleStepCount; level++)
 175         {
 176                 Envelope &e = _envelope_levels[level];
 177                 const Envelope &el = _envelope_levels[level-1];
 178
 179                 // Expand the data buffer to fit the new samples
 180                 prev_length = e.length;
 181                 e.length = el.length / EnvelopeScaleFactor;
 182
 183                 // Break off if there are no more samples to computed
 184                 if (e.length == prev_length)
 185                         break;
 186
 187                 reallocate_envelope(e);
 188
 189                 // Subsample the level lower level
 190                 const EnvelopeSample *src_ptr =
 191                         el.samples + prev_length * EnvelopeScaleFactor;
 192                 const EnvelopeSample *const end_dest_ptr = e.samples + e.length;
 193                 for (dest_ptr = e.samples + prev_length;
 194                         dest_ptr < end_dest_ptr; dest_ptr++)
 195                 {
 196                         const EnvelopeSample *const end_src_ptr =
 197                                 src_ptr + EnvelopeScaleFactor;
 198
 199                         EnvelopeSample sub_sample = *src_ptr++;
 200                         while (src_ptr < end_src_ptr)
 201                         {
 202                                 sub_sample.min = min(sub_sample.min, src_ptr->min);
 203                                 sub_sample.max = max(sub_sample.max, src_ptr->max);
 204                                 src_ptr++;
 205                         }
 206
 207                         *dest_ptr = sub_sample;
 208                 }
 209         }
 210 }
 211
 212 } // namespace data
 213 } // namespace pv