<?php // execution-time.php file

$original = ' Lorem ipsum ';
$translation = ' Lorem ipsum dolor sit ';
$number_of_executions = 10000000;

$time_start = microtime(true);

for ($i=0; $i<$number_of_executions; $i++){
	preg_match( '/^( *)/D', $original, $m );
	$original_start_spaces = strlen( $m[0] );

	preg_match( '/^( *)/D', $translation, $m );
	$translation_start_spaces = strlen( $m[0] );

	preg_match( '/( *)$/D', $original, $m );
	$original_end_spaces = strlen( $m[0] );

	preg_match( '/( *)$/D', $translation, $m );
	$translation_end_spaces = strlen( $m[0] );
}

$time_end = microtime(true);

echo 'Total execution time with regex: '.($time_end - $time_start).' s' . PHP_EOL;

for ($i=0; $i<$number_of_executions; $i++){
	$original_start_spaces    = mb_strlen( $original ) - mb_strlen( ltrim( $original, ' ' ) );
	$original_end_spaces      = mb_strlen( $original ) - mb_strlen( rtrim( $original, ' ' ) );
	$translation_start_spaces = mb_strlen( $translation ) - mb_strlen( ltrim( $translation, ' ' ) );
	$translation_end_spaces   = mb_strlen( $translation ) - mb_strlen( rtrim( $translation, ' ' ) );
}

$time_end = microtime(true);

echo 'Total execution time with mb_strlen: '.($time_end - $time_start).' s'. PHP_EOL;

$ php execution-time.php
Total execution time with regex: 3.5283000469208 s
Total execution time with mb_strlen: 7.8940501213074 s