[php] <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); /** * CodeIgniter * * An open source application development framework for PHP 5.1.6 or newer * * @package CodeIgniter * @author ExpressionEngine Dev Team * @copyright Copyright (c) 2008 - 2011, EllisLab, Inc. * @license http://codeigniter.com/user_guide/license.html * @link http://codeigniter.com * @since Version 1.0 * @filesource */ // ------------------------------------------------------------------------ /** * CodeIgniter Benchmark Class * * This class enables 能夠 you to mark points and calculate 計算 the time difference 差異 * between them. Memory consumption can also be displayed. * * @package CodeIgniter * @subpackage Libraries * @category Libraries * @author ExpressionEngine Dev Team * @link http://codeigniter.com/user_guide/libraries/benchmark.html */ class CI_Benchmark { /** * List of all benchmark markers and when they were added * 用來存儲基准測試類標記的數組 * @var array */ var $marker = array(); // -------------------------------------------------------------------- /** * Set a benchmark marker * 設置一個標記點 * Multiple calls to this function can be made so that several * execution points can be timed * * @access public * @param string $name name of the marker * @return void */ function mark($name) { // 在程序的任意地方調用方法時，會記錄當前的時間點。 $this->marker[$name] = microtime(); } // -------------------------------------------------------------------- /** * Calculates the time difference between two marked points. * 計算出兩個時間點之間的時間。 * If the first parameter is empty this function instead returns the * {elapsed_time} pseudo-variable 虛假變量. This permits 許可 the full system * execution time to be shown in a template. The output class will * swap the real value for this variable. * * @access public * @param string a particular marked point * @param string a particular marked point * @param integer the number of decimal places * @return mixed */ function elapsed_time($point1 = '', $point2 = '', $decimals = 4) { /* * 如果沒有給出明確的時間點，那麼會計算出整個程序運行的時間。 * 怎麼可以做到計算出整個程序的運行時間的呢？其實執行此計算的是Output組件。 * 而調用Benchmark::elapsed_time();（無參數）的時候，實質上先返回的並不是 * 整個程序運行的時間，也不可能做到，實質返回的是一個{elapsed_time}標簽，然後 * Output在處理輸出的時候，再計算出整個程序運行時間，因為處理輸出階段程序可以視 * 為處於最後階段，於是可以近似計算出總時間，然後把輸出中的{elapsed_time}替換掉。 * 下面的memory_usage()原理相同。 */ if ($point1 == '') { return '{elapsed_time}'; } if ( ! isset($this->marker[$point1])) { return ''; } if ( ! isset($this->marker[$point2])) { $this->marker[$point2] = microtime(); } //這裡為什麼要用到list，是因為microtime();返回值是“msec sec”的格式。 list($sm, $ss) = explode(' ', $this->marker[$point1]); list($em, $es) = explode(' ', $this->marker[$point2]); return number_format(($em + $es) - ($sm + $ss), $decimals); } // -------------------------------------------------------------------- /** * Memory Usage * * This function returns the {memory_usage} pseudo-variable. * This permits it to be put it anywhere in a template * without the memory being calculated until the end. * The output class will swap the real value for this variable. * www.2cto.com * @access public * @return string */ function memory_usage() { return '{memory_usage}'; } } // END CI_Benchmark class /* End of file Benchmark.php */ /* Location: ./system/core/Benchmark.php */
