PHP 函数扩展对性能有何影响？

// 通过函数扩展添加字符串反转函数

function strrev_ext($str) {

    return strrev($str);

}

// 使用原始 PHP 函数实现字符串反转

function strrev_php($str) {

    $len = strlen($str);

    $rev = '';

    for ($i = $len - 1; $i >= 0; $i--) {

        $rev .= $str[$i];

    }

    return $rev;

}

// 基准测试

$str = 'Long and complex string';

$iterations = 100000;

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {

    strrev_ext($str);

}

$time_ext = microtime(true) - $start;

$start = microtime(true);

for ($i = 0; $i < $iterations; $i++) {

    strrev_php($str);

}

$time_php = microtime(true) - $start;

// 输出结果

echo "strrev_ext: $time_ext seconds\n";

echo "strrev_php: $time_php seconds\n";