containsMb4

containsMb4.php

<?php

// Download the bible from here: https://bereanbible.com/bsb.txt

ini_set('memory_limit', -1);

require_once 'helpers.php';

echo('Start: ' . convert(memory_get_usage()) . "\r\n");

$string = file_get_contents('bsb.txt');

echo('After File Read: ' . convert(memory_get_usage()) . "\r\n");

function containsMb4(string $str): bool
{
    echo('After containsMb4 Start: ' . convert(memory_get_usage()) . "\r\n");

    $str_splited = str_split($str);

    echo('After str_split: ' . convert(memory_get_usage()) . "\r\n");

    $str_splited_mapped = array_map('ord', $str_splited);

    echo('After array_map: ' . convert(memory_get_usage()) . "\r\n");

    $max = max($str_splited_mapped);

    echo('After max: ' . convert(memory_get_usage()) . "\r\n");

    return $max >= 240;
}

$executionTime = new ExecutionTime();
$executionTime->start();
var_dump(containsMb4($string));
$executionTime->end();
echo $executionTime . "\r\n";

echo('After containsMb4: ' . convert(memory_get_usage()) . "\r\n");
echo('Peak: ' . convert(memory_get_peak_usage()) . "\r\n");

containsMb4Fixed.php

<?php

// Download the bible from here: https://bereanbible.com/bsb.txt

ini_set('memory_limit', -1);

require_once 'helpers.php';

echo('Start: ' . convert(memory_get_usage()) . "\r\n");

$string = file_get_contents('bsb.txt');

echo('After File Read: ' . convert(memory_get_usage()) . "\r\n");

function containsMb4Fixed(string $str): bool
{
    echo('After containsMb4Fixed Start: ' . convert(memory_get_usage()) . "\r\n");

    $length = strlen($str);

    echo('After strlen: ' . convert(memory_get_usage()) . "\r\n");

    for ($i = 0; $i < $length; $i++) {
        if (ord($str[$i]) >= 240) {
            return true;
        }
    }

    echo('After for: ' . convert(memory_get_usage()) . "\r\n");

    return false;
}

$executionTime = new ExecutionTime();
$executionTime->start();
var_dump(containsMb4Fixed($string));
$executionTime->end();
echo $executionTime . "\r\n";

echo('After containsMb4Fixed: ' . convert(memory_get_usage()) . "\r\n");
echo('Peak: ' . convert(memory_get_peak_usage()) . "\r\n");

helpers.php

<?php

class ExecutionTime
{
    private $_startTime;
    private $_endTime;

    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 process 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';
    }
}

function convert($size)
{
    $unit = ['b', 'kb', 'mb', 'gb', 'tb', 'pb'];
    return @round($size / pow(1024, ( $i = floor(log($size, 1024)))), 2) . ' ' . $unit[$i];
}