Text_Diff::_getTempDir

    function _getTempDir()
    {
        $tmp_locations = array('/tmp', '/var/tmp', 'c:\WUTemp', 'c:\temp',
                               'c:\windows\temp', 'c:\winnt\temp');

        /* Try PHP's upload_tmp_dir directive. */
        $tmp = ini_get('upload_tmp_dir');

        /* Otherwise, try to determine the TMPDIR environment variable. */
        if (!strlen($tmp)) {
            $tmp = getenv('TMPDIR');
        }

        /* If we still cannot determine a value, then cycle through a list of
         * preset possibilities. */
        while (!strlen($tmp) && count($tmp_locations)) {
            $tmp_check = array_shift($tmp_locations);
            if (@is_dir($tmp_check)) {
                $tmp = $tmp_check;
            }
        }

        /* If it is still empty, we have failed, so return false; otherwise
         * return the directory determined. */
        return strlen($tmp) ? $tmp : false;
    }