LatinIME/java/src/com/android/inputmethod/latin/BinaryDictionary.java

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/*
* Copyright (C) 2008 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;
import android.content.Context;
import com.android.inputmethod.keyboard.ProximityInfo;
import java.util.Arrays;
import java.util.Locale;
/**
* Implements a static, compacted, binary dictionary of standard words.
*/
public class BinaryDictionary extends Dictionary {
public static final String DICTIONARY_PACK_AUTHORITY =
"com.android.inputmethod.latin.dictionarypack";
/**
* There is a difference between what java and native code can handle.
* This value should only be used in BinaryDictionary.java
* It is necessary to keep it at this value because some languages e.g. German have
* really long words.
*/
public static final int MAX_WORD_LENGTH = 48;
public static final int MAX_WORDS = 18;
private static final String TAG = "BinaryDictionary";
private static final int MAX_BIGRAMS = 60;
private static final int TYPED_LETTER_MULTIPLIER = 2;
private int mDicTypeId;
private long mNativeDict;
private final int[] mInputCodes = new int[MAX_WORD_LENGTH];
private final char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_WORDS];
private final char[] mOutputChars_bigrams = new char[MAX_WORD_LENGTH * MAX_BIGRAMS];
private final int[] mScores = new int[MAX_WORDS];
private final int[] mBigramScores = new int[MAX_BIGRAMS];
private final boolean mUseFullEditDistance;
/**
* Constructor for the binary dictionary. This is supposed to be called from the
* dictionary factory.
* All implementations should pass null into flagArray, except for testing purposes.
* @param context the context to access the environment from.
* @param filename the name of the file to read through native code.
* @param offset the offset of the dictionary data within the file.
* @param length the length of the binary data.
* @param useFullEditDistance whether to use the full edit distance in suggestions
*/
public BinaryDictionary(final Context context,
final String filename, final long offset, final long length,
final boolean useFullEditDistance, final Locale locale) {
// Note: at the moment a binary dictionary is always of the "main" type.
// Initializing this here will help transitioning out of the scheme where
// the Suggest class knows everything about every single dictionary.
mDicTypeId = Suggest.DIC_MAIN;
mUseFullEditDistance = useFullEditDistance;
loadDictionary(filename, offset, length);
}
static {
JniUtils.loadNativeLibrary();
}
private native long openNative(String sourceDir, long dictOffset, long dictSize,
int typedLetterMultiplier, int fullWordMultiplier, int maxWordLength, int maxWords);
private native void closeNative(long dict);
private native boolean isValidWordNative(long dict, char[] word, int wordLength);
private native int getSuggestionsNative(long dict, long proximityInfo, int[] xCoordinates,
int[] yCoordinates, int[] inputCodes, int codesSize, boolean useFullEditDistance,
char[] outputChars, int[] scores);
private native int getBigramsNative(long dict, char[] prevWord, int prevWordLength,
int[] inputCodes, int inputCodesLength, char[] outputChars, int[] scores,
int maxWordLength, int maxBigrams);
private static native double calcNormalizedScoreNative(
char[] before, int beforeLength, char[] after, int afterLength, int score);
private static native int editDistanceNative(
char[] before, int beforeLength, char[] after, int afterLength);
private final void loadDictionary(String path, long startOffset, long length) {
mNativeDict = openNative(path, startOffset, length,
TYPED_LETTER_MULTIPLIER, FULL_WORD_SCORE_MULTIPLIER, MAX_WORD_LENGTH, MAX_WORDS);
}
@Override
public void getBigrams(final WordComposer codes, final CharSequence previousWord,
final WordCallback callback) {
if (mNativeDict == 0) return;
char[] chars = previousWord.toString().toCharArray();
Arrays.fill(mOutputChars_bigrams, (char) 0);
Arrays.fill(mBigramScores, 0);
int codesSize = codes.size();
Arrays.fill(mInputCodes, -1);
if (codesSize > 0) {
mInputCodes[0] = codes.getCodeAt(0);
}
int count = getBigramsNative(mNativeDict, chars, chars.length, mInputCodes, codesSize,
mOutputChars_bigrams, mBigramScores, MAX_WORD_LENGTH, MAX_BIGRAMS);
if (count > MAX_BIGRAMS) {
count = MAX_BIGRAMS;
}
for (int j = 0; j < count; ++j) {
if (codesSize > 0 && mBigramScores[j] < 1) break;
final int start = j * MAX_WORD_LENGTH;
int len = 0;
while (len < MAX_WORD_LENGTH && mOutputChars_bigrams[start + len] != 0) {
++len;
}
if (len > 0) {
callback.addWord(mOutputChars_bigrams, start, len, mBigramScores[j],
mDicTypeId, Dictionary.BIGRAM);
}
}
}
// proximityInfo may not be null.
@Override
public void getWords(final WordComposer codes, final WordCallback callback,
final ProximityInfo proximityInfo) {
final int count = getSuggestions(codes, proximityInfo, mOutputChars, mScores);
for (int j = 0; j < count; ++j) {
if (mScores[j] < 1) break;
final int start = j * MAX_WORD_LENGTH;
int len = 0;
while (len < MAX_WORD_LENGTH && mOutputChars[start + len] != 0) {
++len;
}
if (len > 0) {
callback.addWord(mOutputChars, start, len, mScores[j], mDicTypeId,
Dictionary.UNIGRAM);
}
}
}
/* package for test */ boolean isValidDictionary() {
return mNativeDict != 0;
}
// proximityInfo may not be null.
/* package for test */ int getSuggestions(final WordComposer codes,
final ProximityInfo proximityInfo, char[] outputChars, int[] scores) {
if (!isValidDictionary()) return -1;
final int codesSize = codes.size();
// Won't deal with really long words.
if (codesSize > MAX_WORD_LENGTH - 1) return -1;
Arrays.fill(mInputCodes, WordComposer.NOT_A_CODE);
for (int i = 0; i < codesSize; i++) {
mInputCodes[i] = codes.getCodeAt(i);
}
Arrays.fill(outputChars, (char) 0);
Arrays.fill(scores, 0);
return getSuggestionsNative(
mNativeDict, proximityInfo.getNativeProximityInfo(),
codes.getXCoordinates(), codes.getYCoordinates(), mInputCodes, codesSize,
mUseFullEditDistance, outputChars, scores);
}
public static double calcNormalizedScore(String before, String after, int score) {
return calcNormalizedScoreNative(before.toCharArray(), before.length(),
after.toCharArray(), after.length(), score);
}
public static int editDistance(String before, String after) {
return editDistanceNative(
before.toCharArray(), before.length(), after.toCharArray(), after.length());
}
@Override
public boolean isValidWord(CharSequence word) {
if (word == null) return false;
char[] chars = word.toString().toCharArray();
return isValidWordNative(mNativeDict, chars, chars.length);
}
@Override
public synchronized void close() {
closeInternal();
}
private void closeInternal() {
if (mNativeDict != 0) {
closeNative(mNativeDict);
mNativeDict = 0;
}
}
@Override
protected void finalize() throws Throwable {
try {
closeInternal();
} finally {
super.finalize();
}
}
}