email_validation

protected function validateLocalPart()
{
    // First try to match the local part on the common dot-atom format
    $result = false;

    // Dot-atom characters are: 1*atext *("." 1*atext)
    // atext: ALPHA / DIGIT / and "!", "#", "$", "%", "&", "'", "*",
    //        "+", "-", "/", "=", "?", "^", "_", "`", "{", "|", "}", "~"
    $atext = 'a-zA-Z0-9\x21\x23\x24\x25\x26\x27\x2a\x2b\x2d\x2f\x3d\x3f\x5e\x5f\x60\x7b\x7c\x7d\x7e';
    if (preg_match('/^[' . $atext . ']+(\x2e+[' . $atext . ']+)*$/', $this->localPart)) {
        $result = true;
    } else {
        // Try quoted string format (RFC 5321 Chapter 4.1.2)

        // Quoted-string characters are: DQUOTE *(qtext/quoted-pair) DQUOTE
        $qtext      = '\x20-\x21\x23-\x5b\x5d-\x7e'; // %d32-33 / %d35-91 / %d93-126
        $quotedPair = '\x20-\x7e'; // %d92 %d32-126
        if (preg_match('/^"(['. $qtext .']|\x5c[' . $quotedPair . '])*"$/', $this->localPart)) {
            $result = true;
        } else {
            $this->error(self::DOT_ATOM);
            $this->error(self::QUOTED_STRING);
            $this->error(self::INVALID_LOCAL_PART);
        }
    }

    return $result;
}