map.put("ギ", new String[] { "gi" });
        map.put("グ", new String[] { "gu" });
        map.put("ゲ", new String[] { "ge" });
        map.put("ゴ", new String[] { "go" });

        map.put("ザ", new String[] { "za" });
        map.put("ジ", new String[] { "zi", "ji" });
        map.put("ズ", new String[] { "zu" });
        map.put("ゼ", new String[] { "ze" });
        map.put("ゾ", new String[] { "zo" });

     * @return the parsed charset name, or null if not found
     */
    protected String parseCharset(final String content) {
        final Pattern pattern = Pattern.compile("; *charset *= *([a-zA-Z0-9\\-_]+)", Pattern.CASE_INSENSITIVE);
        final Matcher matcher = pattern.matcher(content);
        if (matcher.find()) {
            return matcher.group(1);
        }
        return null;
    }