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

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/*
* Copyright (C) 2008-2009 Google Inc.
*
* 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 java.util.Arrays;
import android.content.Context;
import android.content.res.AssetManager;
import android.util.Log;
/**
* Implements a static, compacted, binary dictionary of standard words.
*/
public class BinaryDictionary extends Dictionary {
public static final int MAX_WORD_LENGTH = 48;
private static final int MAX_ALTERNATIVES = 16;
private static final int MAX_WORDS = 16;
private static final int TYPED_LETTER_MULTIPLIER = 2;
private static final boolean ENABLE_MISSED_CHARACTERS = true;
private int mNativeDict;
private int[] mInputCodes = new int[MAX_WORD_LENGTH * MAX_ALTERNATIVES];
private WordCallback mWordCallback;
private char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_WORDS];
private int[] mFrequencies = new int[MAX_WORDS];
static {
try {
System.loadLibrary("jni_latinime");
} catch (UnsatisfiedLinkError ule) {
Log.e("BinaryDictionary", "Could not load native library jni_latinime");
}
}
/**
* Create a dictionary from a raw resource file
* @param context application context for reading resources
* @param resId the resource containing the raw binary dictionary
*/
public BinaryDictionary(Context context, int resId) {
if (resId != 0) {
loadDictionary(context, resId);
}
}
private native int openNative(AssetManager am, String resourcePath, int typedLetterMultiplier,
int fullWordMultiplier);
private native void closeNative(int dict);
private native boolean isValidWordNative(int nativeData, char[] word, int wordLength);
private native int getSuggestionsNative(int dict, int[] inputCodes, int codesSize,
char[] outputChars, int[] frequencies,
int maxWordLength, int maxWords, int maxAlternatives, int skipPos);
private final void loadDictionary(Context context, int resId) {
AssetManager am = context.getResources().getAssets();
String assetName = context.getResources().getString(resId);
mNativeDict = openNative(am, assetName, TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER);
}
@Override
public void getWords(final WordComposer codes, final WordCallback callback) {
mWordCallback = callback;
final int codesSize = codes.size();
// Wont deal with really long words.
if (codesSize > MAX_WORD_LENGTH - 1) return;
Arrays.fill(mInputCodes, -1);
for (int i = 0; i < codesSize; i++) {
int[] alternatives = codes.getCodesAt(i);
System.arraycopy(alternatives, 0, mInputCodes, i * MAX_ALTERNATIVES,
Math.min(alternatives.length, MAX_ALTERNATIVES));
}
Arrays.fill(mOutputChars, (char) 0);
Arrays.fill(mFrequencies, 0);
int count = getSuggestionsNative(mNativeDict, mInputCodes, codesSize,
mOutputChars, mFrequencies,
MAX_WORD_LENGTH, MAX_WORDS, MAX_ALTERNATIVES, -1);
// If there aren't sufficient suggestions, search for words by allowing wild cards at
// the different character positions. This feature is not ready for prime-time as we need
// to figure out the best ranking for such words compared to proximity corrections and
// completions.
if (ENABLE_MISSED_CHARACTERS && count < 5) {
for (int skip = 0; skip < codesSize; skip++) {
int tempCount = getSuggestionsNative(mNativeDict, mInputCodes, codesSize,
mOutputChars, mFrequencies,
MAX_WORD_LENGTH, MAX_WORDS, MAX_ALTERNATIVES, skip);
count = Math.max(count, tempCount);
if (tempCount > 0) break;
}
}
for (int j = 0; j < count; j++) {
if (mFrequencies[j] < 1) break;
int start = j * MAX_WORD_LENGTH;
int len = 0;
while (mOutputChars[start + len] != 0) {
len++;
}
if (len > 0) {
callback.addWord(mOutputChars, start, len, mFrequencies[j]);
}
}
}
@Override
public boolean isValidWord(CharSequence word) {
if (word == null) return false;
char[] chars = word.toString().toLowerCase().toCharArray();
return isValidWordNative(mNativeDict, chars, chars.length);
}
public synchronized void close() {
if (mNativeDict != 0) {
closeNative(mNativeDict);
mNativeDict = 0;
}
}
@Override
protected void finalize() throws Throwable {
close();
super.finalize();
}
}