rfc822.php

This is the script which used on 10minutemail.com for temporary email.

    }

    /**
     * A common function that will check an exploded string.
     *
     * @access private
     * @param array $parts The exloded string.
     * @param string $char  The char that was exploded on.
     * @return mixed False if the string contains unclosed quotes/brackets, or the string on success.
     */
    function _splitCheck($parts, $char)
    {
        $string = $parts[0];

        for ($i = 0; $i < count($parts); $i++) {
            if ($this->_hasUnclosedQuotes($string)
                || $this->_hasUnclosedBrackets($string, '<>')
                || $this->_hasUnclosedBrackets($string, '[]')
                || $this->_hasUnclosedBrackets($string, '()')
                || substr($string, -1) == '\\') {
                if (isset($parts[$i + 1])) {
                    $string = $string . $char . $parts[$i + 1];
                } else {
                    $this->error = 'Invalid address spec. Unclosed bracket or quotes';
                    return false;
                }
            } else {
                $this->index = $i;
                break;
            }
        }

        return $string;
    }

    /**
     * Checks if a string has an unclosed quotes or not.
     *
     * @access private
     * @param string $string The string to check.
     * @return boolean True if there are unclosed quotes inside the string, false otherwise.
     */
    function _hasUnclosedQuotes($string)
    {
        $string     = explode('"', $string);
        $string_cnt = count($string);

        for ($i = 0; $i < (count($string) - 1); $i++)
            if (substr($string[$i], -1) == '\\')
                $string_cnt--;

        return ($string_cnt % 2 === 0);
    }

    /**
     * Checks if a string has an unclosed brackets or not. IMPORTANT:
     * This function handles both angle brackets and square brackets;
     *
     * @access private
     * @param string $string The string to check.
     * @param string $chars  The characters to check for.
     * @return boolean True if there are unclosed brackets inside the string, false otherwise.
     */
    function _hasUnclosedBrackets($string, $chars)
    {
        $num_angle_start = substr_count($string, $chars[0]);
        $num_angle_end   = substr_count($string, $chars[1]);

        $this->_hasUnclosedBracketsSub($string, $num_angle_start, $chars[0]);
        $this->_hasUnclosedBracketsSub($string, $num_angle_end, $chars[1]);

        if ($num_angle_start < $num_angle_end) {
            $this->error = 'Invalid address spec. Unmatched quote or bracket (' . $chars . ')';
            return false;
        } else {
            return ($num_angle_start > $num_angle_end);
        }
    }

    /**
     * Sub function that is used only by hasUnclosedBrackets().
     *
     * @access private
     * @param string $string The string to check.
     * @param integer &$num    The number of occurences.
     * @param string $char   The character to count.
     * @return integer The number of occurences of $char in $string, adjusted for backslashes.
     */
    function _hasUnclosedBracketsSub($string, &$num, $char)
    {
        $parts = explode($char, $string);
        for ($i = 0; $i < count($parts); $i++){
            if (substr($parts[$i], -1) == '\\' || $this->_hasUnclosedQuotes($parts[$i]))
                $num--;
            if (isset($parts[$i + 1]))
                $parts[$i + 1] = $parts[$i] . $char . $parts[$i + 1];
        }

        return $num;
    }

    /**
     * Function to begin checking the address.
     *
     * @access private
     * @param string $address The address to validate.
     * @return mixed False on failure, or a structured array of address information on success.
     */
    function _validateAddress($address)
    {
        $is_group = false;
        $addresses = array();

        if ($address['group']) {
            $is_group = true;

            // Get the group part of the name
            $parts     = explode(':', $address['address']);
            $groupname = $this->_splitCheck($parts, ':');
            $structure = array();

            // And validate the group part of the name.
            if (!$this->_validatePhrase($groupname)){
                $this->error = 'Group name did not validate.';
                return false;
            } else {
                // Don't include groups if we are not nesting
                // them. This avoids returning invalid addresses.
                if ($this->nestGroups) {
                    $structure = new stdClass;
                    $structure->groupname = $groupname;
                }
            }

            $address['address'] = ltrim(substr($address['address'], strlen($groupname . ':')));
        }

        // If a group then split on comma and put into an array.
        // Otherwise, Just put the whole address in an array.
        if ($is_group) {
            while (strlen($address['address']) > 0) {
                $parts       = explode(',', $address['address']);
                $addresses[] = $this->_splitCheck($parts, ',');
                $address['address'] = trim(substr($address['address'], strlen(end($addresses) . ',')));
            }
        } else {
            $addresses[] = $address['address'];
        }

        // Check that $addresses is set, if address like this:
        // Groupname:;
        // Then errors were appearing.
        if (!count($addresses)){
            $this->error = 'Empty group.';
            return false;
        }

        // Trim the whitespace from all of the address strings.
        array_map('trim', $addresses);

        // Validate each mailbox.
        // Format could be one of: name <[e-mail]>
        //                         [e-mail]
        //                         geezer
        // ... or any other format valid by RFC 822.
        for ($i = 0; $i < count($addresses); $i++) {
            if (!$this->validateMailbox($addresses[$i])) {
                if (empty($this->error)) {
                    $this->error = 'Validation failed for: ' . $addresses[$i];
                }
                return false;
            }
        }

        // Nested format
        if ($this->nestGroups) {
            if ($is_group) {
                $structure->addresses = $addresses;
            } else {
                $structure = $addresses[0];
            }

        // Flat format
        } else {
            if ($is_group) {
                $structure = array_merge($structure, $addresses);
            } else {
                $structure = $addresses;
            }
        }

        return $structure;
    }

    /**
     * Function to validate a phrase.
     *
     * @access private
     * @param string $phrase The phrase to check.
     * @return boolean Success or failure.
     */
    function _validatePhrase($phrase)
    {
        // Splits on one or more Tab or space.
        $parts = preg_split('/[ \\x09]+/', $phrase, -1, PREG_SPLIT_NO_EMPTY);

        $phrase_parts = array();
        while (count($parts) > 0){
            $phrase_parts[] = $this->_splitCheck($parts, ' ');
            for ($i = 0; $i < $this->index + 1; $i++)
                array_shift($parts);
        }

        foreach ($phrase_parts as $part) {
            // If quoted string:
            if (substr($part, 0, 1) == '"') {
                if (!$this->_validateQuotedString($part)) {
                    return false;
                }
                continue;
            }

            // Otherwise it's an atom:
            if (!$this->_validateAtom($part)) return false;
        }

        return true;
    }

    /**
     * Function to validate an atom which from rfc822 is:
     * atom = 1*<any CHAR except specials, SPACE and CTLs>
     *
     * If validation ($this->validate) has been turned off, then
     * validateAtom() doesn't actually check anything. This is so that you
     * can split a list of addresses up before encoding personal names
     * (umlauts, etc.), for example.
     *
     * @access private
     * @param string $atom The string to check.
     * @return boolean Success or failure.
     */
    function _validateAtom($atom)
    {
        if (!$this->validate) {
            // Validation has been turned off; assume the atom is okay.
            return true;
        }

        // Check for any char from ASCII 0 - ASCII 127
        if (!preg_match('/^[\\x00-\\x7E]+$/i', $atom, $matches)) {
            return false;
        }

        // Check for specials:
        if (preg_match('/[][()<>@,;\\:". ]/', $atom)) {
            return false;
        }

        // Check for control characters (ASCII 0-31):
        if (preg_match('/[\\x00-\\x1F]+/', $atom)) {
            return false;
        }

        return true;
    }

    /**
     * Function to validate quoted string, which is:
     * quoted-string = <"> *(qtext/quoted-pair) <">
     *
     * @access private
     * @param string $qstring The string to check
     * @return boolean Success or failure.
     */
    function _validateQuotedString($qstring)
    {
        // Leading and trailing "
        $qstring = substr($qstring, 1, -1);

        // Perform check, removing quoted characters first.
        return !preg_match('/[\x0D\\\\"]/', preg_replace('/\\\\./', '', $qstring));
    }

    /**
     * Function to validate a mailbox, which is:
     * mailbox =   addr-spec         ; simple address
     *           / phrase route-addr ; name and route-addr
     *
     * @access public
     * @param string &$mailbox The string to check.
     * @return boolean Success or failure.
     */
    function validateMailbox(&$mailbox)
    {
        // A couple of defaults.
        $phrase  = '';
        $comment = '';
        $comments = array();

        // Catch any RFC822 comments and store them separately.
        $_mailbox = $mailbox;
        while (strlen(trim($_mailbox)) > 0) {
            $parts = explode('(', $_mailbox);
            $before_comment = $this->_splitCheck($parts, '(');
            if ($before_comment != $_mailbox) {
                // First char should be a (.
                $comment    = substr(str_replace($before_comment, '', $_mailbox), 1);