245 lines
9.3 KiB
Java
245 lines
9.3 KiB
Java
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.android.inputmethod.latin;
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import android.content.Context;
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import android.util.Log;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.ByteBuffer;
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import java.nio.ByteOrder;
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import java.nio.channels.Channels;
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import java.util.Arrays;
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/**
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* Implements a static, compacted, binary dictionary of standard words.
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*/
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public class BinaryDictionary extends Dictionary {
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/**
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* There is difference between what java and native code can handle.
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* This value should only be used in BinaryDictionary.java
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* It is necessary to keep it at this value because some languages e.g. German have
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* really long words.
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*/
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protected static final int MAX_WORD_LENGTH = 48;
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private static final String TAG = "BinaryDictionary";
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private static final int MAX_ALTERNATIVES = 16;
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private static final int MAX_WORDS = 18;
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private static final int MAX_BIGRAMS = 60;
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private static final int TYPED_LETTER_MULTIPLIER = 2;
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private int mDicTypeId;
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private int mNativeDict;
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private int mDictLength;
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private final int[] mInputCodes = new int[MAX_WORD_LENGTH * MAX_ALTERNATIVES];
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private final char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_WORDS];
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private final char[] mOutputChars_bigrams = new char[MAX_WORD_LENGTH * MAX_BIGRAMS];
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private final int[] mFrequencies = new int[MAX_WORDS];
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private final int[] mFrequencies_bigrams = new int[MAX_BIGRAMS];
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// Keep a reference to the native dict direct buffer in Java to avoid
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// unexpected deallocation of the direct buffer.
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private ByteBuffer mNativeDictDirectBuffer;
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static {
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try {
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System.loadLibrary("jni_latinime");
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} catch (UnsatisfiedLinkError ule) {
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Log.e("BinaryDictionary", "Could not load native library jni_latinime");
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}
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}
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/**
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* Create a dictionary from a raw resource file
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* @param context application context for reading resources
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* @param resId the resource containing the raw binary dictionary
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*/
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public BinaryDictionary(Context context, int[] resId, int dicTypeId) {
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if (resId != null && resId.length > 0 && resId[0] != 0) {
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loadDictionary(context, resId);
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}
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mDicTypeId = dicTypeId;
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}
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/**
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* Create a dictionary from a byte buffer. This is used for testing.
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* @param context application context for reading resources
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* @param byteBuffer a ByteBuffer containing the binary dictionary
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*/
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public BinaryDictionary(Context context, ByteBuffer byteBuffer, int dicTypeId) {
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if (byteBuffer != null) {
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if (byteBuffer.isDirect()) {
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mNativeDictDirectBuffer = byteBuffer;
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} else {
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mNativeDictDirectBuffer = ByteBuffer.allocateDirect(byteBuffer.capacity());
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byteBuffer.rewind();
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mNativeDictDirectBuffer.put(byteBuffer);
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}
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mDictLength = byteBuffer.capacity();
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mNativeDict = openNative(mNativeDictDirectBuffer,
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TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER,
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MAX_WORD_LENGTH, MAX_WORDS, MAX_ALTERNATIVES);
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}
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mDicTypeId = dicTypeId;
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}
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private native int openNative(ByteBuffer bb, int typedLetterMultiplier,
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int fullWordMultiplier, int maxWordLength, int maxWords, int maxAlternatives);
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private native void closeNative(int dict);
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private native boolean isValidWordNative(int nativeData, char[] word, int wordLength);
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private native int getSuggestionsNative(int dict, int[] inputCodes, int codesSize,
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char[] outputChars, int[] frequencies,
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int[] nextLettersFrequencies, int nextLettersSize);
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private native int getBigramsNative(int dict, char[] prevWord, int prevWordLength,
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int[] inputCodes, int inputCodesLength, char[] outputChars, int[] frequencies,
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int maxWordLength, int maxBigrams, int maxAlternatives);
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private final void loadDictionary(Context context, int[] resId) {
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InputStream[] is = null;
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try {
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// merging separated dictionary into one if dictionary is separated
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int total = 0;
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is = new InputStream[resId.length];
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for (int i = 0; i < resId.length; i++) {
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is[i] = context.getResources().openRawResource(resId[i]);
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total += is[i].available();
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}
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mNativeDictDirectBuffer =
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ByteBuffer.allocateDirect(total).order(ByteOrder.nativeOrder());
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int got = 0;
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for (int i = 0; i < resId.length; i++) {
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got += Channels.newChannel(is[i]).read(mNativeDictDirectBuffer);
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}
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if (got != total) {
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Log.e(TAG, "Read " + got + " bytes, expected " + total);
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} else {
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mNativeDict = openNative(mNativeDictDirectBuffer,
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TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER,
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MAX_WORD_LENGTH, MAX_WORDS, MAX_ALTERNATIVES);
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mDictLength = total;
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}
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} catch (IOException e) {
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Log.w(TAG, "No available memory for binary dictionary");
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} finally {
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try {
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if (is != null) {
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for (int i = 0; i < is.length; i++) {
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is[i].close();
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}
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}
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} catch (IOException e) {
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Log.w(TAG, "Failed to close input stream");
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}
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}
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}
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@Override
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public void getBigrams(final WordComposer codes, final CharSequence previousWord,
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final WordCallback callback, int[] nextLettersFrequencies) {
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char[] chars = previousWord.toString().toCharArray();
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Arrays.fill(mOutputChars_bigrams, (char) 0);
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Arrays.fill(mFrequencies_bigrams, 0);
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int codesSize = codes.size();
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Arrays.fill(mInputCodes, -1);
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int[] alternatives = codes.getCodesAt(0);
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System.arraycopy(alternatives, 0, mInputCodes, 0,
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Math.min(alternatives.length, MAX_ALTERNATIVES));
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int count = getBigramsNative(mNativeDict, chars, chars.length, mInputCodes, codesSize,
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mOutputChars_bigrams, mFrequencies_bigrams, MAX_WORD_LENGTH, MAX_BIGRAMS,
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MAX_ALTERNATIVES);
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for (int j = 0; j < count; ++j) {
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if (mFrequencies_bigrams[j] < 1) break;
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final int start = j * MAX_WORD_LENGTH;
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int len = 0;
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while (len < MAX_WORD_LENGTH && mOutputChars_bigrams[start + len] != 0) {
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++len;
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}
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if (len > 0) {
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callback.addWord(mOutputChars_bigrams, start, len, mFrequencies_bigrams[j],
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mDicTypeId, DataType.BIGRAM);
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}
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}
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}
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@Override
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public void getWords(final WordComposer codes, final WordCallback callback,
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int[] nextLettersFrequencies) {
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final int codesSize = codes.size();
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// Won't deal with really long words.
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if (codesSize > MAX_WORD_LENGTH - 1) return;
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Arrays.fill(mInputCodes, -1);
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for (int i = 0; i < codesSize; i++) {
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int[] alternatives = codes.getCodesAt(i);
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System.arraycopy(alternatives, 0, mInputCodes, i * MAX_ALTERNATIVES,
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Math.min(alternatives.length, MAX_ALTERNATIVES));
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}
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Arrays.fill(mOutputChars, (char) 0);
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Arrays.fill(mFrequencies, 0);
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int count = getSuggestionsNative(mNativeDict, mInputCodes, codesSize, mOutputChars,
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mFrequencies, nextLettersFrequencies,
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nextLettersFrequencies != null ? nextLettersFrequencies.length : 0);
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for (int j = 0; j < count; ++j) {
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if (mFrequencies[j] < 1) break;
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final int start = j * MAX_WORD_LENGTH;
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int len = 0;
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while (len < MAX_WORD_LENGTH && mOutputChars[start + len] != 0) {
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++len;
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}
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if (len > 0) {
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callback.addWord(mOutputChars, start, len, mFrequencies[j], mDicTypeId,
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DataType.UNIGRAM);
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}
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}
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}
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@Override
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public boolean isValidWord(CharSequence word) {
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if (word == null) return false;
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char[] chars = word.toString().toCharArray();
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return isValidWordNative(mNativeDict, chars, chars.length);
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}
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public int getSize() {
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return mDictLength; // This value is initialized on the call to openNative()
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}
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@Override
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public synchronized void close() {
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if (mNativeDict != 0) {
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closeNative(mNativeDict);
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mNativeDict = 0;
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}
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}
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@Override
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protected void finalize() throws Throwable {
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close();
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super.finalize();
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}
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}
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