php function for RFC822 - stadart php function and custom variant

validateEmail.php

<?php
// Use: custom regex pattern
function validateEmail($email, $bStrict=false) {
    $pattern = '/^("[\w-\.\s]+")|(?!(?:(?:\x22?\x5C[\x00-\x7E]\x22?)|(?:\x22?[^\x5C\x22]\x22?)){255,})(?!(?:(?:\x22?\x5C[\x00-\x7E]\x22?)|(?:\x22?[^\x5C\x22]\x22?)){65,}@)(?:(?:[\x21\x23-\x27\x2A\x2B\x2D\x2F-\x39\x3D\x3F\x5E-\x7E]+)|(?:\x22(?:[\x01-\x08\x0B\x0C\x0E-\x1F\x21\x23-\x5B\x5D-\x7F]|(?:\x5C[\x00-\x7F]))*\x22))(?:\.(?:(?:[\x21\x23-\x27\x2A\x2B\x2D\x2F-\x39\x3D\x3F\x5E-\x7E]+)|(?:\x22(?:[\x01-\x08\x0B\x0C\x0E-\x1F\x21\x23-\x5B\x5D-\x7F]|(?:\x5C[\x00-\x7F]))*\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-[a-z0-9]+)*\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-[a-z0-9]+)*)|(?:\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\]))$/i';
    if(preg_match($pattern, $email))
        return true;
    else
        return false;
}
// Use: filter_var (php standard function)
function validateEmail2($email) {
    $email = trim($email);
    if (strlen($email)<=0)
        return False;
    if (filter_var($email, FILTER_VALIDATE_EMAIL))
        return true;
    return false;
}
$emails = array(
    'niceandsimple@example.com',
    'very.common@example.com',
    'a.little.lengthy.but.fine@dept.example.com',
    'disposable.style.email.with+symbol@example.com',
    'other.email-with-_dash@example.com',
    'user@[IPv6:2001:db8:1ff::a0b:dbd0]',
    '"much.more unusual"@example.com',
    '"very.unusual.@.unusual.com"@example.com',
    '"very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual"@strange.example.com',
    'postbox@com',
    'admin@mailserver1',
    '!#$%&\'*+-/=?^_`{}|~@example.org',
    '"()<>[]:,;@\\\"!#$%&\'*+-/=?^_`{}| ~.a"@example.org',
    '" "@example.org',
    'üñîçøðé@example.com',
    'üñîçøðé@üñîçøðé.com',
);
$tmp = array();
foreach($emails as $email) {
    $tmp['custome_pattern:'][$email][] = validateEmail($email);
    $tmp['filter_var (php standard function):'][$email][] = validateEmail2($email);
}
var_dump($tmp);