/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.thirdparty.publicsuffix;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import java.util.List;

Parser for a map of reversed domain names stored as a serialized radix tree.
/** Parser for a map of reversed domain names stored as a serialized radix tree. */
@GwtCompatible final class TrieParser { private static final Joiner PREFIX_JOINER = Joiner.on("");
Parses a serialized trie representation of a map of reversed public suffixes into an immutable map of public suffixes.
/** * Parses a serialized trie representation of a map of reversed public suffixes into an immutable * map of public suffixes. */
static ImmutableMap<String, PublicSuffixType> parseTrie(CharSequence encoded) { ImmutableMap.Builder<String, PublicSuffixType> builder = ImmutableMap.builder(); int encodedLen = encoded.length(); int idx = 0; while (idx < encodedLen) { idx += doParseTrieToBuilder(Lists.<CharSequence>newLinkedList(), encoded, idx, builder); } return builder.build(); }
Parses a trie node and returns the number of characters consumed.
Params:
  • stack – The prefixes that precede the characters represented by this node. Each entry of the stack is in reverse order.
  • encoded – The serialized trie.
  • start – An index in the encoded serialized trie to begin reading characters from.
  • builder – A map builder to which all entries will be added.
Returns:The number of characters consumed from encoded.
/** * Parses a trie node and returns the number of characters consumed. * * @param stack The prefixes that precede the characters represented by this node. Each entry of * the stack is in reverse order. * @param encoded The serialized trie. * @param start An index in the encoded serialized trie to begin reading characters from. * @param builder A map builder to which all entries will be added. * @return The number of characters consumed from {@code encoded}. */
private static int doParseTrieToBuilder( List<CharSequence> stack, CharSequence encoded, int start, ImmutableMap.Builder<String, PublicSuffixType> builder) { int encodedLen = encoded.length(); int idx = start; char c = '\0'; // Read all of the characters for this node. for (; idx < encodedLen; idx++) { c = encoded.charAt(idx); if (c == '&' || c == '?' || c == '!' || c == ':' || c == ',') { break; } } stack.add(0, reverse(encoded.subSequence(start, idx))); if (c == '!' || c == '?' || c == ':' || c == ',') { // '!' represents an interior node that represents a REGISTRY entry in the map. // '?' represents a leaf node, which represents a REGISTRY entry in map. // ':' represents an interior node that represents a private entry in the map // ',' represents a leaf node, which represents a private entry in the map. String domain = PREFIX_JOINER.join(stack); if (domain.length() > 0) { builder.put(domain, PublicSuffixType.fromCode(c)); } } idx++; if (c != '?' && c != ',') { while (idx < encodedLen) { // Read all the children idx += doParseTrieToBuilder(stack, encoded, idx, builder); if (encoded.charAt(idx) == '?' || encoded.charAt(idx) == ',') { // An extra '?' or ',' after a child node indicates the end of all children of this node. idx++; break; } } } stack.remove(0); return idx - start; } private static CharSequence reverse(CharSequence s) { return new StringBuilder(s).reverse(); } }