DefaultDnsRecordDecoder implements DnsRecordDecoder { public static String decodeName(ByteBuf in) { int position = -1; int checked = 0; final int end = in.writerIndex(); final int readable = in.readableBytes(); if (readable == 0) { return ROOT; } final StringBuilder name = new StringBuilder(readable << 1); while (in.isReadable()) { final int len = in.readUnsignedByte(); final boolean pointer = (len & 0xc0) == 0xc0; if (pointer) { if (position == -1) { position = in.readerIndex() + 1; } if (!in.isReadable()) { throw new CorruptedFrameException("truncated pointer in a name"); } final int next = (len & 0x3f) << 8 | in.readUnsignedByte(); if (next >= end) { throw new CorruptedFrameException("name has an out-of-range pointer"); } in.readerIndex(next); checked += 2; if (checked >= end) { throw new CorruptedFrameException("name contains a loop."); } } else if (len != 0) { if (!in.isReadable(len)) { throw new CorruptedFrameException("truncated label in a name"); } name.append(in.toString(in.readerIndex(), len, CharsetUtil.UTF_8)).append('.'); in.skipBytes(len); } else { break; } } if (position != -1) { in.readerIndex(position); } if (name.length() == 0) { return ROOT; } if (name.charAt(name.length() - 1) != '.') { name.append('.'); } return name.toString(); } protected  DefaultDnsRecordDecoder(); @Override final DnsQuestion decodeQuestion(ByteBuf in); @Override final T decodeRecord(ByteBuf in); static String decodeName(ByteBuf in);  }
@Test public void testDecodeName() { testDecodeName("netty.io.", Unpooled.wrappedBuffer(new byte[] { 5, 'n', 'e', 't', 't', 'y', 2, 'i', 'o', 0 })); }