stopwatch.bash

#!/bin/bash

function stopwatch {
	local start=${EPOCHREALTIME} diff_i diff_f stop_at= IFS=.
	trap 'stop_at=${EPOCHREALTIME}' INT
	printf '\r\e[K%s.%06d' 0 0

	function stopwatch_get_diff {
		set -- $1 $2
		diff_i=$(( 10#$3 - 10#$1 ))
		diff_f=$(( 10#$4 - 10#$2 ))
		(( diff_f < 0 )) && (( --diff_i, diff_f = 10#"1${4}" - 10#$2 ))
	}

	if enable sleep &>/dev/null; then
		function stopwatch_sleep_10ms { builtin sleep 0.01; }
	else
		function stopwatch_sleep_10ms { read -t0.01 -N1; }
	fi

	until
		stopwatch_sleep_10ms
		[[ ${stop_at} ]]
	do
		stopwatch_get_diff "${start}" "${EPOCHREALTIME}"
		printf '\r\e[K%s.%06d' "${diff_i}" "${diff_f}"
	done

	stopwatch_get_diff "${start}" "${stop_at}"
	printf '\r\e[K%s.%06d\n' "${diff_i}" "${diff_f}"
	unset -f stopwatch_get_diff stopwatch_sleep_10ms
}

# export -f stopwatch
# gnome-terminal -e '/bin/bash -c stopwatch'
stopwatch