From 63aef514d7b6e0793c01989a58eb0529d56052d9 Mon Sep 17 00:00:00 2001
From: Gregory Chamberlain <gregc@posteo.net>
Date: Sun, 31 May 2020 20:30:52 +0100
Subject: [PATCH] Refactor nettraf

No longer relies on paste(1p).
---
 .local/bin/statusbar/nettraf | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/.local/bin/statusbar/nettraf b/.local/bin/statusbar/nettraf
index 6972b7e..42da6d0 100755
--- a/.local/bin/statusbar/nettraf
+++ b/.local/bin/statusbar/nettraf
@@ -10,13 +10,19 @@ case $BLOCK_BUTTON in
 	6) "$TERMINAL" -e "$EDITOR" "$0" ;;
 esac
 
-logfile=${XDG_CACHE_HOME:-$HOME/.cache}/netlog
-[ -f "$logfile" ] || echo "0 0" > "$logfile"
-read -r rxprev txprev < "$logfile"
+update() {
+    sum=0
+    for arg; do
+        read -r i < "$arg"
+        sum=$(( "$sum" + "$i" ))
+    done
+    cache=${XDG_CACHE_HOME:-$HOME/.cache}/${1##*/}
+    [ -f "$cache" ] && read -r old < "$cache" || old=0
+    printf %d\\n "$sum" > "$cache"
+    printf %d\\n $(( ("$sum" - "$old") / 1024 ))
+}
 
-rxcurrent=$(($(paste -d '+' /sys/class/net/[ew]*/statistics/rx_bytes)))
-txcurrent=$(($(paste -d '+' /sys/class/net/[ew]*/statistics/tx_bytes)))
+rx=$(update /sys/class/net/[ew]*/statistics/rx_bytes)
+tx=$(update /sys/class/net/[ew]*/statistics/tx_bytes)
 
-printf "🔻%dKiB 🔺%dKiB\\n" "$(((rxcurrent-rxprev)/1024))" "$(((txcurrent-txprev)/1024))"
-
-echo "$rxcurrent $txcurrent" > "$logfile"
+printf "🔻%dKiB 🔺%dKiB\\n" "$rx" "$tx"