add SI bytes TXRX

reporttypes.go

@@ -102,6 +102,8 @@ func GenerateReport(dev *wgtypes.Device, conf *DsnetConfig, oldReport *DsnetRepo
 			LastHandshakeTime: wgPeer.LastHandshakeTime,
 			ReceiveBytes:      wgPeer.ReceiveBytes,
 			TransmitBytes:     wgPeer.TransmitBytes,
+			ReceiveBytesSI:    BytesToSI(wgPeer.ReceiveBytes),
+			TransmitBytesSI:   BytesToSI(wgPeer.TransmitBytes),
 		}
 	}
 
@@ -161,4 +163,6 @@ type PeerReport struct {
 	LastHandshakeTime time.Time
 	ReceiveBytes      int64
 	TransmitBytes     int64
+	ReceiveBytesSI    string
+	TransmitBytesSI   string
 }

util.go

@@ -48,3 +48,17 @@ func ConfirmOrAbort(format string, a ...interface{}) {
 		ExitFail("Aborted.")
 	}
 }
+
+func BytesToSI(b int64) string {
+	const unit = 1000
+	if b < unit {
+		return fmt.Sprintf("%d B", b)
+	}
+	div, exp := int64(unit), 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.1f %cB",
+		float64(b)/float64(div), "kMGTPE"[exp])
+}