add socks_decoder, stratum_decoder and session_flags

decoders/session_flags/onlinemean.c

@@ -0,0 +1,37 @@
+#include <math.h>
+#include "onlinemean.h"
+
+void OnlineMean_Init(OnlineMean_t *oMean) {
+	OnlineMean_Reset(oMean);
+}
+
+void OnlineMean_Update(OnlineMean_t *oMean, float newValue) {
+	oMean->count++;
+	if (oMean->count > 1) {
+		float delta = newValue - oMean->mean;
+		oMean->mean += delta / oMean->count;
+		oMean->varsum += delta * (newValue - oMean->mean);
+	} else {
+		oMean->mean = newValue;
+	}
+}
+
+float OnlineMean_GetMean(OnlineMean_t *oMean) {
+	return oMean->mean;
+}
+
+float OnlineMean_GetStd(OnlineMean_t *oMean) {
+	if (oMean->count == 0)
+		return 0;
+#if UNBIASED_ESTIMATOR
+	return sqrt(oMean->varsum / (oMean->count - 1));
+#else
+	return sqrt(oMean->varsum / oMean->count);
+#endif  /* UNBIASED_ESTIMATOR */
+}
+
+void OnlineMean_Reset(OnlineMean_t *oMean) {
+	oMean->count = 0;
+	oMean->mean = 0.f;
+	oMean->varsum = 0.f;
+}