Parse a human readable size back to bytes

from-human-readable.php

<?php

function parseSize($size)
{
    $unit = preg_replace('/[^bkmgtpezy]/i', '', $size); // Remove the non-unit characters from the size.
    $size = preg_replace('/[^0-9\.]/', '', $size); // Remove the non-numeric characters from the size.
    if ($unit) {
        // Find the position of the unit in the ordered string which is the power of magnitude to multiply a kilobyte by.
        return $bytesSize = $size * pow(1024, stripos('bkmgtpezy', $unit[0]));
    }
    return round($size);
}