public function writeToString(array $config, $header = '')
    {
        $ini = $header;

        $sectionNames = array_keys($config);

        foreach ($sectionNames as $sectionName) {
            $section = $config[$sectionName];

            // no point in writing empty sections
            if (empty($section)) {
                continue;
            }

            if (! is_array($section)) {
                throw new IniWritingException(sprintf("Section \"%s\" doesn't contain an array of values", $sectionName));
            }

            $ini .= "[$sectionName]\n";

            foreach ($section as $option => $value) {
                if (is_numeric($option)) {
                    $option = $sectionName;
                    $value = array($value);
                }

                if (is_array($value)) {
                    foreach ($value as $currentValue) {
                        $ini .= $option . '[] = ' . $this->encodeValue($currentValue) . "\n";
                    }
                } else {
                    $ini .= $option . ' = ' . $this->encodeValue($value) . "\n";
                }
            }

            $ini .= "\n";
        }

        return $ini;
    }