<?php
/*
 * $executionTime = new agile_tix_ExecutionTime('process name');
	$executionTime->start();
	// Code
	$executionTime->end();
	echo $executionTime;
 */
class agile_tix_ExecutionTime {

	private $startTime;
	private $endTime;
	private $processName;

	public function __construct( string $process ) {
		$this->processName = $process;
	}

	public function start() {
		$this->startTime = getrusage();
	}

	public function end() {
		$this->endTime = getrusage();
	}

	private function runTime( $ru, $rus, $index ) {
		return ( $ru[ "ru_$index.tv_sec" ] * 1000 + intval( $ru[ "ru_$index.tv_usec" ] / 1000 ) )
		- ( $rus[ "ru_$index.tv_sec" ] * 1000 + intval( $rus[ "ru_$index.tv_usec" ] / 1000 ) );
	}

	public function __toString() {
		return $this->processName . ' used ' . $this->runTime( $this->endTime, $this->startTime, 'utime' ) .
		" ms for its computations\nIt spent " . $this->runTime( $this->endTime, $this->startTime, 'stime' ) .
		" ms in system calls\n";
	}
}