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[pulseview.git] / 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(const uint64_t expected_num_samples) :
51         Snapshot(sizeof(float))
52 {
53         set_capacity(expected_num_samples);
54
55         lock_guard<recursive_mutex> lock(_mutex);
56         memset(_envelope_levels, 0, sizeof(_envelope_levels));
57 }
58
59 AnalogSnapshot::~AnalogSnapshot()
60 {
61         lock_guard<recursive_mutex> lock(_mutex);
62         BOOST_FOREACH(Envelope &e, _envelope_levels)
63                 free(e.samples);
64 }
65
66 void AnalogSnapshot::append_interleaved_samples(const float *data,
67         size_t sample_count, size_t stride)
68 {
69         assert(_unit_size == sizeof(float));
70
71         lock_guard<recursive_mutex> lock(_mutex);
72
73         _data = realloc(_data, (_sample_count + sample_count) * sizeof(float));
74
75         float *dst = (float*)_data + _sample_count;
76         const float *dst_end = dst + sample_count;
77         while (dst != dst_end)
78         {
79                 *dst++ = *data;
80                 data += stride;
81         }
82
83         _sample_count += sample_count;
84
85         // Generate the first mip-map from the data
86         append_payload_to_envelope_levels();
87 }
88
89 const float* AnalogSnapshot::get_samples(
90         int64_t start_sample, int64_t end_sample) const
91 {
92         assert(start_sample >= 0);
93         assert(start_sample < (int64_t)_sample_count);
94         assert(end_sample >= 0);
95         assert(end_sample < (int64_t)_sample_count);
96         assert(start_sample <= end_sample);
97
98         lock_guard<recursive_mutex> lock(_mutex);
99
100         float *const data = new float[end_sample - start_sample];
101         memcpy(data, (float*)_data + start_sample, sizeof(float) *
102                 (end_sample - start_sample));
103         return data;
104 }
105
106 void AnalogSnapshot::get_envelope_section(EnvelopeSection &s,
107         uint64_t start, uint64_t end, float min_length) const
108 {
109         assert(end <= get_sample_count());
110         assert(start <= end);
111         assert(min_length > 0);
112
113         lock_guard<recursive_mutex> lock(_mutex);
114
115         const unsigned int min_level = max((int)floorf(logf(min_length) /
116                 LogEnvelopeScaleFactor) - 1, 0);
117         const unsigned int scale_power = (min_level + 1) *
118                 EnvelopeScalePower;
119         start >>= scale_power;
120         end >>= scale_power;
121
122         s.start = start << scale_power;
123         s.scale = 1 << scale_power;
124         s.length = end - start;
125         s.samples = new EnvelopeSample[s.length];
126         memcpy(s.samples, _envelope_levels[min_level].samples + start,
127                 s.length * sizeof(EnvelopeSample));
128 }
129
130 void AnalogSnapshot::reallocate_envelope(Envelope &e)
131 {
132         const uint64_t new_data_length = ((e.length + EnvelopeDataUnit - 1) /
133                 EnvelopeDataUnit) * EnvelopeDataUnit;
134         if (new_data_length > e.data_length)
135         {
136                 e.data_length = new_data_length;
137                 e.samples = (EnvelopeSample*)realloc(e.samples,
138                         new_data_length * sizeof(EnvelopeSample));
139         }
140 }
141
142 void AnalogSnapshot::append_payload_to_envelope_levels()
143 {
144         Envelope &e0 = _envelope_levels[0];
145         uint64_t prev_length;
146         EnvelopeSample *dest_ptr;
147
148         // Expand the data buffer to fit the new samples
149         prev_length = e0.length;
150         e0.length = _sample_count / EnvelopeScaleFactor;
151
152         // Break off if there are no new samples to compute
153         if (e0.length == prev_length)
154                 return;
155
156         reallocate_envelope(e0);
157
158         dest_ptr = e0.samples + prev_length;
159
160         // Iterate through the samples to populate the first level mipmap
161         const float *const end_src_ptr = (float*)_data +
162                 e0.length * EnvelopeScaleFactor;
163         for (const float *src_ptr = (float*)_data +
164                 prev_length * EnvelopeScaleFactor;
165                 src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor)
166         {
167                 const EnvelopeSample sub_sample = {
168                         *min_element(src_ptr, src_ptr + EnvelopeScaleFactor),
169                         *max_element(src_ptr, src_ptr + EnvelopeScaleFactor),
170                 };
171
172                 *dest_ptr++ = sub_sample;
173         }
174
175         // Compute higher level mipmaps
176         for (unsigned int level = 1; level < ScaleStepCount; level++)
177         {
178                 Envelope &e = _envelope_levels[level];
179                 const Envelope &el = _envelope_levels[level-1];
180
181                 // Expand the data buffer to fit the new samples
182                 prev_length = e.length;
183                 e.length = el.length / EnvelopeScaleFactor;
184
185                 // Break off if there are no more samples to computed
186                 if (e.length == prev_length)
187                         break;
188
189                 reallocate_envelope(e);
190
191                 // Subsample the level lower level
192                 const EnvelopeSample *src_ptr =
193                         el.samples + prev_length * EnvelopeScaleFactor;
194                 const EnvelopeSample *const end_dest_ptr = e.samples + e.length;
195                 for (dest_ptr = e.samples + prev_length;
196                         dest_ptr < end_dest_ptr; dest_ptr++)
197                 {
198                         const EnvelopeSample *const end_src_ptr =
199                                 src_ptr + EnvelopeScaleFactor;
200
201                         EnvelopeSample sub_sample = *src_ptr++;
202                         while (src_ptr < end_src_ptr)
203                         {
204                                 sub_sample.min = min(sub_sample.min, src_ptr->min);
205                                 sub_sample.max = max(sub_sample.max, src_ptr->max);
206                                 src_ptr++;
207                         }
208
209                         *dest_ptr = sub_sample;
210                 }
211         }
212 }
213
214 } // namespace data
215 } // namespace pv