EaglerForge/sources/main/java/com/google/thirdparty/publicsuffix/TrieParser.java

134 lines
4.1 KiB
Java

/*
* 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 java.util.List;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
/**
* Parser for a map of reversed domain names stored as a serialized radix tree.
*/
@GwtCompatible
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.
*/
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.subSequence(idx, encodedLen),
builder);
}
return builder.build();
}
/**
* Parses a trie node and returns the number of characters consumed.
*
* @param stack The prefixes that preceed the characters represented by this
* node. Each entry of the stack is in reverse order.
* @param encoded The serialized trie.
* @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,
ImmutableMap.Builder<String, PublicSuffixType> builder) {
int encodedLen = encoded.length();
int idx = 0;
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(0, idx)));
if (c == '!' || c == '?' || c == ':' || c == ',') {
// '!' represents an interior node that represents an ICANN entry in the map.
// '?' represents a leaf node, which represents an ICANN 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.subSequence(idx, encodedLen), 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;
}
/**
* Reverses a character sequence. This is borrowed from
* https://code.google.com/p/google-web-toolkit/source/detail?r=11591# and can
* be replaced with a simple {@code StringBuffer#reverse} once GWT 2.6 is
* available.
*/
private static CharSequence reverse(CharSequence s) {
int length = s.length();
if (length <= 1) {
return s;
}
char[] buffer = new char[length];
buffer[0] = s.charAt(length - 1);
for (int i = 1; i < length; i++) {
buffer[i] = s.charAt(length - 1 - i);
if (Character.isSurrogatePair(buffer[i], buffer[i - 1])) {
swap(buffer, i - 1, i);
}
}
return new String(buffer);
}
private static void swap(char[] buffer, int f, int s) {
char tmp = buffer[f];
buffer[f] = buffer[s];
buffer[s] = tmp;
}
}