1 #include "average.hpp"
2
3 #include <cassert>
4
5 std::optional<Average::averageValue>
getAverageValue(const Average::averageKey & sensorKey) const6 Average::getAverageValue(const Average::averageKey& sensorKey) const
7 {
8 const auto it = _previousAverageMap.find(sensorKey);
9 if (it == _previousAverageMap.end())
10 {
11 return {};
12 }
13
14 return std::optional(it->second);
15 }
16
setAverageValue(const Average::averageKey & sensorKey,const Average::averageValue & sensorValue)17 void Average::setAverageValue(const Average::averageKey& sensorKey,
18 const Average::averageValue& sensorValue)
19 {
20 _previousAverageMap[sensorKey] = sensorValue;
21 }
22
23 std::optional<int64_t>
calcAverage(int64_t preAverage,int64_t preInterval,int64_t curAverage,int64_t curInterval)24 Average::calcAverage(int64_t preAverage, int64_t preInterval,
25 int64_t curAverage, int64_t curInterval)
26 {
27 int64_t value = 0;
28 // Estimate that the interval will overflow about 292471
29 // years after it starts counting, so consider it won't
30 // overflow
31 int64_t delta = curInterval - preInterval;
32
33 assert(delta >= 0);
34 // 0 means the delta interval is too short, the value of
35 // power*_average_interval is not changed yet
36 if (delta == 0)
37 {
38 return {};
39 }
40 // Change formula (a2*i2-a1*i1)/(i2-i1) to be the
41 // following formula, to avoid multiplication overflow.
42 // (a2*i2-a1*i1)/(i2-i1) =
43 // (a2*(i1+delta)-a1*i1)/delta =
44 // (a2-a1)(i1/delta)+a2
45 value =
46 (curAverage - preAverage) * (static_cast<double>(preInterval) / delta) +
47 curAverage;
48
49 return value;
50 }
51