php upper lower for standard en chars

char_lo_up.php

<?php
setlocale(LC_CTYPE, 'de_DE.UTF8');
function myUpper($char){
    $lo = ord($char);
    $up = $lo & 0x5f;
    return $up;
}
function myLower($char){
    $up = ord($char);
    $lo = $up ^ 0x20;
    return $lo;
}

echo chr(myUpper('h'));
echo strtoupper('ô');
echo mb_convert_case('ô', MB_CASE_UPPER, "UTF-8");
// see also https://gitlab.snuipp.fr/snusoft/api_carte_scolaire/blob/master/vendor/symfony/polyfill-mbstring/Resources/unidata/lowerCase.php
?>