class PdfNameTree {

    private static final int leafSize = 64;


    /**
     * Writes a name tree to a PdfWriter.
     *
     * @param items  the item of the name tree. The key is a <CODE>String</CODE> and the value is a
     *               <CODE>PdfObject</CODE>. Note that although the keys are strings only the lower byte is used and no
     *               check is made for chars with the same lower byte and different upper byte. This will generate a
     *               wrong tree name.
     * @param writer the writer
     * @return the dictionary with the name tree. This dictionary is the one generally pointed to by the key /Dests, for
     * example
     * @throws IOException on error
     */
    public static PdfDictionary writeTree(HashMap<String, ? extends PdfObject> items, PdfWriter writer)
            throws IOException {
        return writeTree((Map<String, ? extends PdfObject>) items, writer);
    }

    /**
     * Writes a name tree to a PdfWriter.
     *
     * @param items  the item of the name tree. The key is a <CODE>String</CODE> and the value is a
     *               <CODE>PdfObject</CODE>. Note that although the keys are strings only the lower byte is used and no
     *               check is made for chars with the same lower byte and different upper byte. This will generate a
     *               wrong tree name.
     * @param writer the writer
     * @return the dictionary with the name tree. This dictionary is the one generally pointed to by the key /Dests, for
     * example
     * @throws IOException on error
     */
    public static PdfDictionary writeTree(Map<String, ? extends PdfObject> items, PdfWriter writer) throws IOException {<FILL_FUNCTION_BODY>}

    private static void iterateItems(PdfDictionary dic, HashMap<String, PdfObject> items) {
        PdfArray nn = (PdfArray) PdfReader.getPdfObjectRelease(dic.get(PdfName.NAMES));
        if (nn != null) {
            for (int k = 0; k < nn.size(); ++k) {
                PdfString s = (PdfString) PdfReader.getPdfObjectRelease(nn.getPdfObject(k++));
                items.put(PdfEncodings.convertToString(s.getBytes(), null), nn.getPdfObject(k));
            }
        } else if ((nn = (PdfArray) PdfReader.getPdfObjectRelease(dic.get(PdfName.KIDS))) != null) {
            for (int k = 0; k < nn.size(); ++k) {
                PdfDictionary kid = (PdfDictionary) PdfReader.getPdfObjectRelease(nn.getPdfObject(k));
                iterateItems(kid, items);
            }
        }
    }

    public static HashMap<String, PdfObject> readTree(PdfDictionary dic) {
        HashMap<String, PdfObject> items = new HashMap<>();
        if (dic != null) {
            iterateItems(dic, items);
        }
        return items;
    }
}

        if (items.isEmpty()) {
            return null;
        }
        String[] names = items.keySet().toArray(new String[0]);
        Arrays.sort(names);
        if (names.length <= leafSize) {
            PdfDictionary dic = new PdfDictionary();
            PdfArray ar = new PdfArray();
            for (String name : names) {
                ar.add(new PdfString(name, null));
                ar.add(items.get(name));
            }
            dic.put(PdfName.NAMES, ar);
            return dic;
        }
        int skip = leafSize;
        PdfIndirectReference[] kids = new PdfIndirectReference[(names.length + leafSize - 1) / leafSize];
        for (int k = 0; k < kids.length; ++k) {
            int offset = k * leafSize;
            int end = Math.min(offset + leafSize, names.length);
            PdfDictionary dic = new PdfDictionary();
            PdfArray arr = new PdfArray();
            arr.add(new PdfString(names[offset], null));
            arr.add(new PdfString(names[end - 1], null));
            dic.put(PdfName.LIMITS, arr);
            arr = new PdfArray();
            for (; offset < end; ++offset) {
                arr.add(new PdfString(names[offset], null));
                arr.add(items.get(names[offset]));
            }
            dic.put(PdfName.NAMES, arr);
            kids[k] = writer.addToBody(dic).getIndirectReference();
        }
        int top = kids.length;
        while (true) {
            if (top <= leafSize) {
                PdfArray arr = new PdfArray();
                for (int k = 0; k < top; ++k) {
                    arr.add(kids[k]);
                }
                PdfDictionary dic = new PdfDictionary();
                dic.put(PdfName.KIDS, arr);
                return dic;
            }
            skip *= leafSize;
            int tt = (names.length + skip - 1) / skip;
            for (int k = 0; k < tt; ++k) {
                int offset = k * leafSize;
                int end = Math.min(offset + leafSize, top);
                PdfDictionary dic = new PdfDictionary();
                PdfArray arr = new PdfArray();
                arr.add(new PdfString(names[k * skip], null));
                arr.add(new PdfString(names[Math.min((k + 1) * skip, names.length) - 1], null));
                dic.put(PdfName.LIMITS, arr);
                arr = new PdfArray();
                for (; offset < end; ++offset) {
                    arr.add(kids[offset]);
                }
                dic.put(PdfName.KIDS, arr);
                kids[k] = writer.addToBody(dic).getIndirectReference();
            }
            top = tt;
        }
    
<no_super_class>