Delete values that are older than 1 hour

include/timeseries.h

@@ -2,11 +2,11 @@
 
 #include <stdint.h>
 
-#include <vector>
+#include <deque>
 
 typedef struct {
     uint64_t tstart, tend, interval;
-    std::vector<float> data;
+    std::deque<float> data;
     const char *unit;
     const char *format;
 } timeseries_t;
@@ -14,3 +14,6 @@ typedef struct {
 void timeseries_init(timeseries_t *ts, uint64_t tstart, uint64_t interval, const char *unit, const char *format);
 
 void timeseries_append(timeseries_t *ts, float value);
+
+// remove oldest values
+void timeseries_prune(timeseries_t *ts, float duration);

src/epaper.cpp

@@ -65,7 +65,7 @@ void epaper_draw_and_hibernate(epaper_callback cb, bool full_refresh)
 
 // find minimum and maximum values in a vector. NaN is ignored.
 	template<typename T>
-void minmax(const std::vector<T> &vec, T *min, T *max)
+void minmax(const std::deque<T> &vec, T *min, T *max)
 {
 	bool first = true;
 

src/main.cpp

@@ -157,7 +157,7 @@ static void draw_epaper_initial_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLAS
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSans12pt7b);
-	display->print("Connected to WLAN: ");
+	display->print("WLAN verbunden: ");
 
 	y += FreeSans12pt7b.yAdvance;
 	display->setCursor(0, y);
@@ -181,7 +181,7 @@ static void draw_epaper_initial_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLAS
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSans12pt7b);
-	display->print("Initial time: ");
+	display->print("Synchronisierte Zeit: ");
 
 	y += FreeSans12pt7b.yAdvance;
 	display->setCursor(0, y);
@@ -348,6 +348,8 @@ void loop(void)
 		if((now - lastEPaperRefresh) >= 60000) {
 			lastEPaperRefresh = now;
 			epaper_draw_and_hibernate(draw_epaper_callback, false);
+
+			timeseries_prune(&ts_scd30_humidity, 3600); // keep the last hour
 		}
 
 		/*

src/timeseries.cpp

@@ -16,3 +16,17 @@ void timeseries_append(timeseries_t *ts, float value)
 	ts->data.push_back(value);
 	ts->tend += ts->interval;
 }
+
+
+void timeseries_prune(timeseries_t *ts, float duration)
+{
+	std::deque<float>::size_type to_keep = duration / ts->interval;
+	if(to_keep >= ts->data.size()) {
+		return;
+	}
+
+	std::deque<float>::size_type to_delete = ts->data.size() - to_keep;
+	ts->data.erase(ts->data.begin(), ts->data.begin() + to_delete);
+
+	ts->tstart += to_delete * ts->interval;
+}