* ICANN. Examples of registry suffixes include {@code com}, {@code co.uk}, and {@code
   * pvt.k12.wy.us}. Examples of domain names that are <i>not</i> registry suffixes include {@code
   * google.com} and {@code foo.co.uk}.
   *
   * <p>Registry suffixes are a proper subset of {@linkplain #isPublicSuffix() public suffixes}. The
   * list of public suffixes additionally contains privately owned domain names under which Internet

@GwtCompatible
final class TrieParser {

  private static final Joiner DIRECT_JOINER = Joiner.on("");

  /**
   * Parses a serialized trie representation of a map of reversed public suffixes into an immutable
   * map of public suffixes. The encoded trie string may be broken into multiple chunks to avoid the
   * 64k limit on string literal size. In-memory strings can be much larger (2G).
   */

      ImmutableSet.of("www", "foo.ihopethiswillneverbeapublicsuffix", "x.y.z");

  /**
   * Having a public suffix is equivalent to having a registry suffix, because all registry suffixes
   * are public suffixes, and all public suffixes have registry suffixes.
   */
  private static final ImmutableSet<String> NO_RS = NO_PS;

  private static final ImmutableSet<String> NON_PS =
      ImmutableSet.of(
          // keep-sorted start

  /**
   * The elements in this map would pass the UNDER test, but are known not to be public suffixes and
   * are thus excluded from consideration. Since it refers to elements in UNDER of the same type,
   * the type is actually not important here. The map is simply used for consistency reasons.
   */