private function createCharsetTableVariables(array $config, $encoding_type = 'utf8')
    {
        if (isset($config['sphinxsearch']) && file_exists(__DIR__ . '/config/sphinx.charset.utf8.config.php')) {
            $charsetConfig = include __DIR__ . '/config/sphinx.charset.utf8.config.php';
            $languages = $charsetConfig['languages'];
            $defaults = $charsetConfig['defaults'];
            $prefix = 'charset_' . $encoding_type . '_';
            // Inject default charset table variables
            foreach ($defaults as $name => $table) {
                $config['sphinxsearch']['variables'][$prefix . $name] = $table;
            }
            $default = implode(', ', $defaults);
            $config['sphinxsearch']['variables'][$prefix . 'default'] = $default;
            // Inject language charset table variables
            foreach ($languages as $lang => $table) {
                if (empty($table)) {
                    $config['sphinxsearch']['variables'][$prefix . $lang] = $default;
                } else {
                    $alphanum = '';
                    $alphanum .= $config['sphinxsearch']['variables'][$prefix . 'digits'] . ', ';
                    $alphanum .= $config['sphinxsearch']['variables'][$prefix . 'alphabet'];
                    $config['sphinxsearch']['variables'][$prefix . $lang] = $alphanum . ', ' . $table;
                }
            }
        }
        return $config;
    }