From ff6bc38826ea584061f7c575ab5de9a514eb4832 Mon Sep 17 00:00:00 2001
From: Denis Kolodin <DenisKolodin@gmail.com>
Date: Thu, 7 Oct 2021 18:37:41 +0300
Subject: [PATCH] fix: use intermediate u64 to calculate average (#3432)

Description
---
Calculates `AverageLatency` using `u64` intermediate state.

Motivation and Context
---
If the samples are large enough the average sum can overflow. Using `u64` makes this event less likely.

How Has This Been Tested?
---
Manually. Function only.
---
 base_layer/p2p/src/services/liveness/state.rs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/base_layer/p2p/src/services/liveness/state.rs b/base_layer/p2p/src/services/liveness/state.rs
index a4d9c50928..383652a2ab 100644
--- a/base_layer/p2p/src/services/liveness/state.rs
+++ b/base_layer/p2p/src/services/liveness/state.rs
@@ -24,6 +24,7 @@ use crate::proto::liveness::MetadataKey;
 use chrono::{NaiveDateTime, Utc};
 use std::{
     collections::{hash_map::RandomState, HashMap},
+    convert::TryInto,
     time::Duration,
 };
 use tari_comms::peer_manager::NodeId;
@@ -224,12 +225,14 @@ impl AverageLatency {
 
     /// Calculate the average of the recorded samples
     pub fn calc_average(&self) -> u32 {
-        let samples = &self.samples;
-        if samples.is_empty() {
-            return 0;
-        }
-
-        samples.iter().fold(0, |sum, x| sum + *x) / samples.len() as u32
+        self.samples
+            .iter()
+            .map(|x| u64::from(*x))
+            .fold(0, u64::saturating_add)
+            .checked_div(self.samples.len() as u64)
+            .unwrap_or_default()
+            .try_into()
+            .unwrap_or(u32::MAX)
     }
 }