Something went wrong on our end
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Yuichiro Hanada authored
Bug: 9618601 Change-Id: I161d2845906f07c1251deb8005fdffe49c5b7940
Yuichiro Hanada authoredBug: 9618601 Change-Id: I161d2845906f07c1251deb8005fdffe49c5b7940
FusionDictionary.java 39.00 KiB
/*
* Copyright (C) 2011 The Android Open Source Project
*
* 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.android.inputmethod.latin.makedict;
import com.android.inputmethod.annotations.UsedForTesting;
import com.android.inputmethod.latin.Constants;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
/**
* A dictionary that can fusion heads and tails of words for more compression.
*/
@UsedForTesting
public final class FusionDictionary implements Iterable<Word> {
private static final boolean DBG = MakedictLog.DBG;
private static int CHARACTER_NOT_FOUND_INDEX = -1;
/**
* A node array of the dictionary, containing several PtNodes.
*
* A PtNodeArray is but an ordered array of PtNodes, which essentially contain all the
* real information.
* This class also contains fields to cache size and address, to help with binary
* generation.
*/
public static final class PtNodeArray {
ArrayList<PtNode> mData;
// To help with binary generation
int mCachedSize = Integer.MIN_VALUE;
// mCachedAddressBefore/AfterUpdate are helpers for binary dictionary generation. They
// always hold the same value except between dictionary address compression, during which
// the update process needs to know about both values at the same time. Updating will
// update the AfterUpdate value, and the code will move them to BeforeUpdate before
// the next update pass.
int mCachedAddressBeforeUpdate = Integer.MIN_VALUE;
int mCachedAddressAfterUpdate = Integer.MIN_VALUE;
int mCachedParentAddress = 0;
public PtNodeArray() {
mData = new ArrayList<PtNode>();
}
public PtNodeArray(ArrayList<PtNode> data) {
mData = data;
}
}
/**
* A string with a frequency.
* * This represents an "attribute", that is either a bigram or a shortcut.
*/
public static final class WeightedString {
public final String mWord;
public int mFrequency;
public WeightedString(String word, int frequency) {
mWord = word;
mFrequency = frequency;
}
@Override
public int hashCode() {
return Arrays.hashCode(new Object[] { mWord, mFrequency });
}
@Override
public boolean equals(Object o) {
if (o == this) return true;
if (!(o instanceof WeightedString)) return false;
WeightedString w = (WeightedString)o;
return mWord.equals(w.mWord) && mFrequency == w.mFrequency;
}
}
/**
* PtNode is a group of characters, with a frequency, shortcut targets, bigrams, and children
* (Pt means Patricia Trie).
*
* This is the central class of the in-memory representation. A PtNode is what can
* be seen as a traditional "trie node", except it can hold several characters at the
* same time. A PtNode essentially represents one or several characters in the middle
* of the trie tree; as such, it can be a terminal, and it can have children.
* In this in-memory representation, whether the PtNode is a terminal or not is represented
* in the frequency, where NOT_A_TERMINAL (= -1) means this is not a terminal and any other
* value is the frequency of this terminal. A terminal may have non-null shortcuts and/or
* bigrams, but a non-terminal may not. Moreover, children, if present, are null.
*/
public static final class PtNode {
public static final int NOT_A_TERMINAL = -1;
final int mChars[];
ArrayList<WeightedString> mShortcutTargets;
ArrayList<WeightedString> mBigrams;
int mFrequency; // NOT_A_TERMINAL == mFrequency indicates this is not a terminal.
int mTerminalId; // NOT_A_TERMINAL == mTerminalId indicates this is not a terminal.
PtNodeArray mChildren;
boolean mIsNotAWord; // Only a shortcut
boolean mIsBlacklistEntry;
// mCachedSize and mCachedAddressBefore/AfterUpdate are helpers for binary dictionary
// generation. Before and After always hold the same value except during dictionary
// address compression, where the update process needs to know about both values at the
// same time. Updating will update the AfterUpdate value, and the code will move them
// to BeforeUpdate before the next update pass.
// The update process does not need two versions of mCachedSize.
int mCachedSize; // The size, in bytes, of this PtNode.
int mCachedAddressBeforeUpdate; // The address of this PtNode (before update)
int mCachedAddressAfterUpdate; // The address of this PtNode (after update)
public PtNode(final int[] chars, final ArrayList<WeightedString> shortcutTargets,
final ArrayList<WeightedString> bigrams, final int frequency,
final boolean isNotAWord, final boolean isBlacklistEntry) {
mChars = chars;
mFrequency = frequency;
mTerminalId = frequency;
mShortcutTargets = shortcutTargets;
mBigrams = bigrams;
mChildren = null;
mIsNotAWord = isNotAWord;
mIsBlacklistEntry = isBlacklistEntry;
}
public PtNode(final int[] chars, final ArrayList<WeightedString> shortcutTargets,
final ArrayList<WeightedString> bigrams, final int frequency,
final boolean isNotAWord, final boolean isBlacklistEntry,
final PtNodeArray children) {
mChars = chars;
mFrequency = frequency;
mShortcutTargets = shortcutTargets;
mBigrams = bigrams;
mChildren = children;
mIsNotAWord = isNotAWord;
mIsBlacklistEntry = isBlacklistEntry;
}
public void addChild(PtNode n) {
if (null == mChildren) {
mChildren = new PtNodeArray();
}
mChildren.mData.add(n);
}
public int getTerminalId() {
return mTerminalId;
}
public boolean isTerminal() {
return NOT_A_TERMINAL != mFrequency;
}
public int getFrequency() {
return mFrequency;
}
public boolean getIsNotAWord() {
return mIsNotAWord;
}
public boolean getIsBlacklistEntry() {
return mIsBlacklistEntry;
}
public ArrayList<WeightedString> getShortcutTargets() {
// We don't want write permission to escape outside the package, so we return a copy
if (null == mShortcutTargets) return null;
final ArrayList<WeightedString> copyOfShortcutTargets =
new ArrayList<WeightedString>(mShortcutTargets);
return copyOfShortcutTargets;
}
public ArrayList<WeightedString> getBigrams() {
// We don't want write permission to escape outside the package, so we return a copy
if (null == mBigrams) return null;
final ArrayList<WeightedString> copyOfBigrams = new ArrayList<WeightedString>(mBigrams);
return copyOfBigrams;
}
public boolean hasSeveralChars() {
assert(mChars.length > 0);
return 1 < mChars.length;
}
/**
* Adds a word to the bigram list. Updates the frequency if the word already
* exists.
*/
public void addBigram(final String word, final int frequency) {
if (mBigrams == null) {
mBigrams = new ArrayList<WeightedString>();
}
WeightedString bigram = getBigram(word);
if (bigram != null) { bigram.mFrequency = frequency;
} else {
bigram = new WeightedString(word, frequency);
mBigrams.add(bigram);
}
}
/**
* Gets the shortcut target for the given word. Returns null if the word is not in the
* shortcut list.
*/
public WeightedString getShortcut(final String word) {
// TODO: Don't do a linear search
if (mShortcutTargets != null) {
final int size = mShortcutTargets.size();
for (int i = 0; i < size; ++i) {
WeightedString shortcut = mShortcutTargets.get(i);
if (shortcut.mWord.equals(word)) {
return shortcut;
}
}
}
return null;
}
/**
* Gets the bigram for the given word.
* Returns null if the word is not in the bigrams list.
*/
public WeightedString getBigram(final String word) {
// TODO: Don't do a linear search
if (mBigrams != null) {
final int size = mBigrams.size();
for (int i = 0; i < size; ++i) {
WeightedString bigram = mBigrams.get(i);
if (bigram.mWord.equals(word)) {
return bigram;
}
}
}
return null;
}
/**
* Updates the PtNode with the given properties. Adds the shortcut and bigram lists to
* the existing ones if any. Note: unigram, bigram, and shortcut frequencies are only
* updated if they are higher than the existing ones.
*/
public void update(final int frequency, final ArrayList<WeightedString> shortcutTargets,
final ArrayList<WeightedString> bigrams,
final boolean isNotAWord, final boolean isBlacklistEntry) {
if (frequency > mFrequency) {
mFrequency = frequency;
}
if (shortcutTargets != null) {
if (mShortcutTargets == null) {
mShortcutTargets = shortcutTargets;
} else {
final int size = shortcutTargets.size();
for (int i = 0; i < size; ++i) {
final WeightedString shortcut = shortcutTargets.get(i);
final WeightedString existingShortcut = getShortcut(shortcut.mWord);
if (existingShortcut == null) {
mShortcutTargets.add(shortcut);
} else if (existingShortcut.mFrequency < shortcut.mFrequency) {
existingShortcut.mFrequency = shortcut.mFrequency;
}
}
}
} if (bigrams != null) {
if (mBigrams == null) {
mBigrams = bigrams;
} else {
final int size = bigrams.size();
for (int i = 0; i < size; ++i) {
final WeightedString bigram = bigrams.get(i);
final WeightedString existingBigram = getBigram(bigram.mWord);
if (existingBigram == null) {
mBigrams.add(bigram);
} else if (existingBigram.mFrequency < bigram.mFrequency) {
existingBigram.mFrequency = bigram.mFrequency;
}
}
}
}
mIsNotAWord = isNotAWord;
mIsBlacklistEntry = isBlacklistEntry;
}
}
/**
* Options global to the dictionary.
*/
public static final class DictionaryOptions {
public final boolean mGermanUmlautProcessing;
public final boolean mFrenchLigatureProcessing;
public final HashMap<String, String> mAttributes;
public DictionaryOptions(final HashMap<String, String> attributes,
final boolean germanUmlautProcessing, final boolean frenchLigatureProcessing) {
mAttributes = attributes;
mGermanUmlautProcessing = germanUmlautProcessing;
mFrenchLigatureProcessing = frenchLigatureProcessing;
}
@Override
public String toString() { // Convenience method
return toString(0, false);
}
public String toString(final int indentCount, final boolean plumbing) {
final StringBuilder indent = new StringBuilder();
if (plumbing) {
indent.append("H:");
} else {
for (int i = 0; i < indentCount; ++i) {
indent.append(" ");
}
}
final StringBuilder s = new StringBuilder();
for (final String optionKey : mAttributes.keySet()) {
s.append(indent);
s.append(optionKey);
s.append(" = ");
if ("date".equals(optionKey) && !plumbing) {
// Date needs a number of milliseconds, but the dictionary contains seconds
s.append(new Date(
1000 * Long.parseLong(mAttributes.get(optionKey))).toString());
} else {
s.append(mAttributes.get(optionKey));
}
s.append("\n");
}
if (mGermanUmlautProcessing) {
s.append(indent);
s.append("Needs German umlaut processing\n");
}
if (mFrenchLigatureProcessing) {
s.append(indent);
s.append("Needs French ligature processing\n");
}
return s.toString(); }
}
public final DictionaryOptions mOptions;
public final PtNodeArray mRootNodeArray;
public FusionDictionary(final PtNodeArray rootNodeArray, final DictionaryOptions options) {
mRootNodeArray = rootNodeArray;
mOptions = options;
}
public void addOptionAttribute(final String key, final String value) {
mOptions.mAttributes.put(key, value);
}
/**
* Helper method to convert a String to an int array.
*/
static int[] getCodePoints(final String word) {
// TODO: this is a copy-paste of the contents of StringUtils.toCodePointArray,
// which is not visible from the makedict package. Factor this code.
final char[] characters = word.toCharArray();
final int length = characters.length;
final int[] codePoints = new int[Character.codePointCount(characters, 0, length)];
int codePoint = Character.codePointAt(characters, 0);
int dsti = 0;
for (int srci = Character.charCount(codePoint);
srci < length; srci += Character.charCount(codePoint), ++dsti) {
codePoints[dsti] = codePoint;
codePoint = Character.codePointAt(characters, srci);
}
codePoints[dsti] = codePoint;
return codePoints;
}
/**
* Helper method to add a word as a string.
*
* This method adds a word to the dictionary with the given frequency. Optional
* lists of bigrams and shortcuts can be passed here. For each word inside,
* they will be added to the dictionary as necessary.
*
* @param word the word to add.
* @param frequency the frequency of the word, in the range [0..255].
* @param shortcutTargets a list of shortcut targets for this word, or null.
* @param isNotAWord true if this should not be considered a word (e.g. shortcut only)
*/
public void add(final String word, final int frequency,
final ArrayList<WeightedString> shortcutTargets, final boolean isNotAWord) {
add(getCodePoints(word), frequency, shortcutTargets, isNotAWord,
false /* isBlacklistEntry */);
}
/**
* Helper method to add a blacklist entry as a string.
*
* @param word the word to add as a blacklist entry.
* @param shortcutTargets a list of shortcut targets for this word, or null.
* @param isNotAWord true if this is not a word for spellcheking purposes (shortcut only or so)
*/
public void addBlacklistEntry(final String word,
final ArrayList<WeightedString> shortcutTargets, final boolean isNotAWord) {
add(getCodePoints(word), 0, shortcutTargets, isNotAWord, true /* isBlacklistEntry */);
}
/**
* Sanity check for a PtNode array.
*
* This method checks that all PtNodes in a node array are ordered as expected.
* If they are, nothing happens. If they aren't, an exception is thrown. */
private void checkStack(PtNodeArray ptNodeArray) {
ArrayList<PtNode> stack = ptNodeArray.mData;
int lastValue = -1;
for (int i = 0; i < stack.size(); ++i) {
int currentValue = stack.get(i).mChars[0];
if (currentValue <= lastValue)
throw new RuntimeException("Invalid stack");
else
lastValue = currentValue;
}
}
/**
* Helper method to add a new bigram to the dictionary.
*
* @param word1 the previous word of the context
* @param word2 the next word of the context
* @param frequency the bigram frequency
*/
public void setBigram(final String word1, final String word2, final int frequency) {
PtNode ptNode = findWordInTree(mRootNodeArray, word1);
if (ptNode != null) {
final PtNode ptNode2 = findWordInTree(mRootNodeArray, word2);
if (ptNode2 == null) {
add(getCodePoints(word2), 0, null, false /* isNotAWord */,
false /* isBlacklistEntry */);
// The PtNode for the first word may have moved by the above insertion,
// if word1 and word2 share a common stem that happens not to have been
// a cutting point until now. In this case, we need to refresh ptNode.
ptNode = findWordInTree(mRootNodeArray, word1);
}
ptNode.addBigram(word2, frequency);
} else {
throw new RuntimeException("First word of bigram not found");
}
}
/**
* Add a word to this dictionary.
*
* The shortcuts, if any, have to be in the dictionary already. If they aren't,
* an exception is thrown.
*
* @param word the word, as an int array.
* @param frequency the frequency of the word, in the range [0..255].
* @param shortcutTargets an optional list of shortcut targets for this word (null if none).
* @param isNotAWord true if this is not a word for spellcheking purposes (shortcut only or so)
* @param isBlacklistEntry true if this is a blacklisted word, false otherwise
*/
private void add(final int[] word, final int frequency,
final ArrayList<WeightedString> shortcutTargets,
final boolean isNotAWord, final boolean isBlacklistEntry) {
assert(frequency >= 0 && frequency <= 255);
if (word.length >= Constants.DICTIONARY_MAX_WORD_LENGTH) {
MakedictLog.w("Ignoring a word that is too long: word.length = " + word.length);
return;
}
PtNodeArray currentNodeArray = mRootNodeArray;
int charIndex = 0;
PtNode currentPtNode = null;
int differentCharIndex = 0; // Set by the loop to the index of the char that differs
int nodeIndex = findIndexOfChar(mRootNodeArray, word[charIndex]);
while (CHARACTER_NOT_FOUND_INDEX != nodeIndex) {
currentPtNode = currentNodeArray.mData.get(nodeIndex);
differentCharIndex = compareCharArrays(currentPtNode.mChars, word, charIndex);
if (ARRAYS_ARE_EQUAL != differentCharIndex
&& differentCharIndex < currentPtNode.mChars.length) break; if (null == currentPtNode.mChildren) break;
charIndex += currentPtNode.mChars.length;
if (charIndex >= word.length) break;
currentNodeArray = currentPtNode.mChildren;
nodeIndex = findIndexOfChar(currentNodeArray, word[charIndex]);
}
if (CHARACTER_NOT_FOUND_INDEX == nodeIndex) {
// No node at this point to accept the word. Create one.
final int insertionIndex = findInsertionIndex(currentNodeArray, word[charIndex]);
final PtNode newPtNode = new PtNode(Arrays.copyOfRange(word, charIndex, word.length),
shortcutTargets, null /* bigrams */, frequency, isNotAWord, isBlacklistEntry);
currentNodeArray.mData.add(insertionIndex, newPtNode);
if (DBG) checkStack(currentNodeArray);
} else {
// There is a word with a common prefix.
if (differentCharIndex == currentPtNode.mChars.length) {
if (charIndex + differentCharIndex >= word.length) {
// The new word is a prefix of an existing word, but the node on which it
// should end already exists as is. Since the old PtNode was not a terminal,
// make it one by filling in its frequency and other attributes
currentPtNode.update(frequency, shortcutTargets, null, isNotAWord,
isBlacklistEntry);
} else {
// The new word matches the full old word and extends past it.
// We only have to create a new node and add it to the end of this.
final PtNode newNode = new PtNode(
Arrays.copyOfRange(word, charIndex + differentCharIndex, word.length),
shortcutTargets, null /* bigrams */, frequency, isNotAWord,
isBlacklistEntry);
currentPtNode.mChildren = new PtNodeArray();
currentPtNode.mChildren.mData.add(newNode);
}
} else {
if (0 == differentCharIndex) {
// Exact same word. Update the frequency if higher. This will also add the
// new shortcuts to the existing shortcut list if it already exists.
currentPtNode.update(frequency, shortcutTargets, null,
currentPtNode.mIsNotAWord && isNotAWord,
currentPtNode.mIsBlacklistEntry || isBlacklistEntry);
} else {
// Partial prefix match only. We have to replace the current node with a node
// containing the current prefix and create two new ones for the tails.
PtNodeArray newChildren = new PtNodeArray();
final PtNode newOldWord = new PtNode(
Arrays.copyOfRange(currentPtNode.mChars, differentCharIndex,
currentPtNode.mChars.length), currentPtNode.mShortcutTargets,
currentPtNode.mBigrams, currentPtNode.mFrequency,
currentPtNode.mIsNotAWord, currentPtNode.mIsBlacklistEntry,
currentPtNode.mChildren);
newChildren.mData.add(newOldWord);
final PtNode newParent;
if (charIndex + differentCharIndex >= word.length) {
newParent = new PtNode(
Arrays.copyOfRange(currentPtNode.mChars, 0, differentCharIndex),
shortcutTargets, null /* bigrams */, frequency,
isNotAWord, isBlacklistEntry, newChildren);
} else {
newParent = new PtNode(
Arrays.copyOfRange(currentPtNode.mChars, 0, differentCharIndex),
null /* shortcutTargets */, null /* bigrams */, -1,
false /* isNotAWord */, false /* isBlacklistEntry */, newChildren);
final PtNode newWord = new PtNode(Arrays.copyOfRange(word,
charIndex + differentCharIndex, word.length),
shortcutTargets, null /* bigrams */, frequency,
isNotAWord, isBlacklistEntry);
final int addIndex = word[charIndex + differentCharIndex]
> currentPtNode.mChars[differentCharIndex] ? 1 : 0;
newChildren.mData.add(addIndex, newWord); }
currentNodeArray.mData.set(nodeIndex, newParent);
}
if (DBG) checkStack(currentNodeArray);
}
}
}
private static int ARRAYS_ARE_EQUAL = 0;
/**
* Custom comparison of two int arrays taken to contain character codes.
*
* This method compares the two arrays passed as an argument in a lexicographic way,
* with an offset in the dst string.
* This method does NOT test for the first character. It is taken to be equal.
* I repeat: this method starts the comparison at 1 <> dstOffset + 1.
* The index where the strings differ is returned. ARRAYS_ARE_EQUAL = 0 is returned if the
* strings are equal. This works BECAUSE we don't look at the first character.
*
* @param src the left-hand side string of the comparison.
* @param dst the right-hand side string of the comparison.
* @param dstOffset the offset in the right-hand side string.
* @return the index at which the strings differ, or ARRAYS_ARE_EQUAL = 0 if they don't.
*/
private static int compareCharArrays(final int[] src, final int[] dst, int dstOffset) {
// We do NOT test the first char, because we come from a method that already
// tested it.
for (int i = 1; i < src.length; ++i) {
if (dstOffset + i >= dst.length) return i;
if (src[i] != dst[dstOffset + i]) return i;
}
if (dst.length > src.length) return src.length;
return ARRAYS_ARE_EQUAL;
}
/**
* Helper class that compares and sorts two PtNodes according to their
* first element only. I repeat: ONLY the first element is considered, the rest
* is ignored.
* This comparator imposes orderings that are inconsistent with equals.
*/
static private final class PtNodeComparator implements java.util.Comparator<PtNode> {
@Override
public int compare(PtNode p1, PtNode p2) {
if (p1.mChars[0] == p2.mChars[0]) return 0;
return p1.mChars[0] < p2.mChars[0] ? -1 : 1;
}
}
final static private PtNodeComparator PTNODE_COMPARATOR = new PtNodeComparator();
/**
* Finds the insertion index of a character within a node array.
*/
private static int findInsertionIndex(final PtNodeArray nodeArray, int character) {
final ArrayList<PtNode> data = nodeArray.mData;
final PtNode reference = new PtNode(new int[] { character },
null /* shortcutTargets */, null /* bigrams */, 0, false /* isNotAWord */,
false /* isBlacklistEntry */);
int result = Collections.binarySearch(data, reference, PTNODE_COMPARATOR);
return result >= 0 ? result : -result - 1;
}
/**
* Find the index of a char in a node array, if it exists.
*
* @param nodeArray the node array to search in.
* @param character the character to search for.
* @return the position of the character if it's there, or CHARACTER_NOT_FOUND_INDEX = -1 else.
*/ private static int findIndexOfChar(final PtNodeArray nodeArray, int character) {
final int insertionIndex = findInsertionIndex(nodeArray, character);
if (nodeArray.mData.size() <= insertionIndex) return CHARACTER_NOT_FOUND_INDEX;
return character == nodeArray.mData.get(insertionIndex).mChars[0] ? insertionIndex
: CHARACTER_NOT_FOUND_INDEX;
}
/**
* Helper method to find a word in a given branch.
*/
@SuppressWarnings("unused")
public static PtNode findWordInTree(PtNodeArray nodeArray, final String string) {
int index = 0;
final StringBuilder checker = DBG ? new StringBuilder() : null;
final int[] codePoints = getCodePoints(string);
PtNode currentPtNode;
do {
int indexOfGroup = findIndexOfChar(nodeArray, codePoints[index]);
if (CHARACTER_NOT_FOUND_INDEX == indexOfGroup) return null;
currentPtNode = nodeArray.mData.get(indexOfGroup);
if (codePoints.length - index < currentPtNode.mChars.length) return null;
int newIndex = index;
while (newIndex < codePoints.length && newIndex - index < currentPtNode.mChars.length) {
if (currentPtNode.mChars[newIndex - index] != codePoints[newIndex]) return null;
newIndex++;
}
index = newIndex;
if (DBG) {
checker.append(new String(currentPtNode.mChars, 0, currentPtNode.mChars.length));
}
if (index < codePoints.length) {
nodeArray = currentPtNode.mChildren;
}
} while (null != nodeArray && index < codePoints.length);
if (index < codePoints.length) return null;
if (!currentPtNode.isTerminal()) return null;
if (DBG && !string.equals(checker.toString())) return null;
return currentPtNode;
}
/**
* Helper method to find out whether a word is in the dict or not.
*/
public boolean hasWord(final String s) {
if (null == s || "".equals(s)) {
throw new RuntimeException("Can't search for a null or empty string");
}
return null != findWordInTree(mRootNodeArray, s);
}
/**
* Recursively count the number of PtNodes in a given branch of the trie.
*
* @param nodeArray the parent node.
* @return the number of PtNodes in all the branch under this node.
*/
public static int countPtNodes(final PtNodeArray nodeArray) {
final int nodeSize = nodeArray.mData.size();
int size = nodeSize;
for (int i = nodeSize - 1; i >= 0; --i) {
PtNode ptNode = nodeArray.mData.get(i);
if (null != ptNode.mChildren)
size += countPtNodes(ptNode.mChildren);
}
return size;
}
/**
* Recursively count the number of nodes in a given branch of the trie.
*
* @param nodeArray the node array to count.
* @return the number of nodes in this branch.
*/
public static int countNodeArrays(final PtNodeArray nodeArray) {
int size = 1;
for (int i = nodeArray.mData.size() - 1; i >= 0; --i) {
PtNode ptNode = nodeArray.mData.get(i);
if (null != ptNode.mChildren)
size += countNodeArrays(ptNode.mChildren);
}
return size;
}
// Recursively find out whether there are any bigrams.
// This can be pretty expensive especially if there aren't any (we return as soon
// as we find one, so it's much cheaper if there are bigrams)
private static boolean hasBigramsInternal(final PtNodeArray nodeArray) {
if (null == nodeArray) return false;
for (int i = nodeArray.mData.size() - 1; i >= 0; --i) {
PtNode ptNode = nodeArray.mData.get(i);
if (null != ptNode.mBigrams) return true;
if (hasBigramsInternal(ptNode.mChildren)) return true;
}
return false;
}
/**
* Finds out whether there are any bigrams in this dictionary.
*
* @return true if there is any bigram, false otherwise.
*/
// TODO: this is expensive especially for large dictionaries without any bigram.
// The up side is, this is always accurate and correct and uses no memory. We should
// find a more efficient way of doing this, without compromising too much on memory
// and ease of use.
public boolean hasBigrams() {
return hasBigramsInternal(mRootNodeArray);
}
// Historically, the tails of the words were going to be merged to save space.
// However, that would prevent the code to search for a specific address in log(n)
// time so this was abandoned.
// The code is still of interest as it does add some compression to any dictionary
// that has no need for attributes. Implementations that does not read attributes should be
// able to read a dictionary with merged tails.
// Also, the following code does support frequencies, as in, it will only merges
// tails that share the same frequency. Though it would result in the above loss of
// performance while searching by address, it is still technically possible to merge
// tails that contain attributes, but this code does not take that into account - it does
// not compare attributes and will merge terminals with different attributes regardless.
public void mergeTails() {
MakedictLog.i("Do not merge tails");
return;
// MakedictLog.i("Merging PtNodes. Number of PtNodes : " + countPtNodes(root));
// MakedictLog.i("Number of PtNodes : " + countPtNodes(root));
//
// final HashMap<String, ArrayList<PtNodeArray>> repository =
// new HashMap<String, ArrayList<PtNodeArray>>();
// mergeTailsInner(repository, root);
//
// MakedictLog.i("Number of different pseudohashes : " + repository.size());
// int size = 0;
// for (ArrayList<PtNodeArray> a : repository.values()) {
// size += a.size();
// }// MakedictLog.i("Number of nodes after merge : " + (1 + size));
// MakedictLog.i("Recursively seen nodes : " + countNodes(root));
}
// The following methods are used by the deactivated mergeTails()
// private static boolean isEqual(PtNodeArray a, PtNodeArray b) {
// if (null == a && null == b) return true;
// if (null == a || null == b) return false;
// if (a.data.size() != b.data.size()) return false;
// final int size = a.data.size();
// for (int i = size - 1; i >= 0; --i) {
// PtNode aPtNode = a.data.get(i);
// PtNode bPtNode = b.data.get(i);
// if (aPtNode.frequency != bPtNode.frequency) return false;
// if (aPtNode.alternates == null && bPtNode.alternates != null) return false;
// if (aPtNode.alternates != null && !aPtNode.equals(bPtNode.alternates)) return false;
// if (!Arrays.equals(aPtNode.chars, bPtNode.chars)) return false;
// if (!isEqual(aPtNode.children, bPtNode.children)) return false;
// }
// return true;
// }
// static private HashMap<String, ArrayList<PtNodeArray>> mergeTailsInner(
// final HashMap<String, ArrayList<PtNodeArray>> map, final PtNodeArray nodeArray) {
// final ArrayList<PtNode> branches = nodeArray.data;
// final int nodeSize = branches.size();
// for (int i = 0; i < nodeSize; ++i) {
// PtNode ptNode = branches.get(i);
// if (null != ptNode.children) {
// String pseudoHash = getPseudoHash(ptNode.children);
// ArrayList<PtNodeArray> similarList = map.get(pseudoHash);
// if (null == similarList) {
// similarList = new ArrayList<PtNodeArray>();
// map.put(pseudoHash, similarList);
// }
// boolean merged = false;
// for (PtNodeArray similar : similarList) {
// if (isEqual(ptNode.children, similar)) {
// ptNode.children = similar;
// merged = true;
// break;
// }
// }
// if (!merged) {
// similarList.add(ptNode.children);
// }
// mergeTailsInner(map, ptNode.children);
// }
// }
// return map;
// }
// private static String getPseudoHash(final PtNodeArray nodeArray) {
// StringBuilder s = new StringBuilder();
// for (PtNode ptNode : nodeArray.data) {
// s.append(ptNode.frequency);
// for (int ch : ptNode.chars) {
// s.append(Character.toChars(ch));
// }
// }
// return s.toString();
// }
/**
* Iterator to walk through a dictionary.
*
* This is purely for convenience.
*/
public static final class DictionaryIterator implements Iterator<Word> {
private static final class Position { public Iterator<PtNode> pos;
public int length;
public Position(ArrayList<PtNode> ptNodes) {
pos = ptNodes.iterator();
length = 0;
}
}
final StringBuilder mCurrentString;
final LinkedList<Position> mPositions;
public DictionaryIterator(ArrayList<PtNode> ptRoot) {
mCurrentString = new StringBuilder();
mPositions = new LinkedList<Position>();
final Position rootPos = new Position(ptRoot);
mPositions.add(rootPos);
}
@Override
public boolean hasNext() {
for (Position p : mPositions) {
if (p.pos.hasNext()) {
return true;
}
}
return false;
}
@Override
public Word next() {
Position currentPos = mPositions.getLast();
mCurrentString.setLength(currentPos.length);
do {
if (currentPos.pos.hasNext()) {
final PtNode currentPtNode = currentPos.pos.next();
currentPos.length = mCurrentString.length();
for (int i : currentPtNode.mChars) {
mCurrentString.append(Character.toChars(i));
}
if (null != currentPtNode.mChildren) {
currentPos = new Position(currentPtNode.mChildren.mData);
currentPos.length = mCurrentString.length();
mPositions.addLast(currentPos);
}
if (currentPtNode.mFrequency >= 0) {
return new Word(mCurrentString.toString(), currentPtNode.mFrequency,
currentPtNode.mShortcutTargets, currentPtNode.mBigrams,
currentPtNode.mIsNotAWord, currentPtNode.mIsBlacklistEntry);
}
} else {
mPositions.removeLast();
currentPos = mPositions.getLast();
mCurrentString.setLength(mPositions.getLast().length);
}
} while (true);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Unsupported yet");
}
}
/**
* Method to return an iterator.
*
* This method enables Java's enhanced for loop. With this you can have a FusionDictionary x
* and say : for (Word w : x) {}
*/ @Override
public Iterator<Word> iterator() {
return new DictionaryIterator(mRootNodeArray.mData);
}
}