/*
* 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.s16.inputmethod.skeyboard;
import java.io.InputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.Channels;
import java.util.Arrays;
import android.content.Context;
import android.util.Log;
/**
* Implements a static, compacted, binary dictionary of standard words.
*/
public class BinaryDictionary extends Dictionary {
/**
* There is 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.
*/
protected static final int MAX_WORD_LENGTH = 48;
private static final String TAG = "BinaryDictionary";
private static final int MAX_ALTERNATIVES = 16;
private static final int MAX_WORDS = 18;
private static final int MAX_BIGRAMS = 60;
private static final int TYPED_LETTER_MULTIPLIER = 2;
private static final boolean ENABLE_MISSED_CHARACTERS = true;
private int mDicTypeId;
private int mNativeDict;
private int mDictLength;
private int[] mInputCodes = new int[MAX_WORD_LENGTH * MAX_ALTERNATIVES];
private char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_WORDS];
private char[] mOutputChars_bigrams = new char[MAX_WORD_LENGTH * MAX_BIGRAMS];
private int[] mFrequencies = new int[MAX_WORDS];
private int[] mFrequencies_bigrams = new int[MAX_BIGRAMS];
// Keep a reference to the native dict direct buffer in Java to avoid
// unexpected deallocation of the direct buffer.
private ByteBuffer mNativeDictDirectBuffer;
static {
try {
System.loadLibrary("jni_skeyboard");
} catch (UnsatisfiedLinkError ule) {
Log.e(TAG, "Could not load native library jni_skeyboard");
}
}
/**
* 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, int dicTypeId) {
if (resId != null && resId.length > 0 && resId[0] != 0) {
loadDictionary(context, resId);
}
mDicTypeId = dicTypeId;
}
/**
* Create a dictionary from input streams
* @param context application context for reading resources
* @param streams the resource streams containing the raw binary dictionary
*/
public BinaryDictionary(Context context, InputStream[] streams, int dicTypeId) {
if (streams != null && streams.length > 0) {
loadDictionary(streams);
}
mDicTypeId = dicTypeId;
}
/**
* Create a dictionary from a byte buffer. This is used for testing.
* @param context application context for reading resources
* @param byteBuffer a ByteBuffer containing the binary dictionary
*/
public BinaryDictionary(Context context, ByteBuffer byteBuffer, int dicTypeId) {
if (byteBuffer != null) {
if (byteBuffer.isDirect()) {
mNativeDictDirectBuffer = byteBuffer;
} else {
mNativeDictDirectBuffer = ByteBuffer.allocateDirect(byteBuffer.capacity());
byteBuffer.rewind();
mNativeDictDirectBuffer.put(byteBuffer);
}
mDictLength = byteBuffer.capacity();
mNativeDict = openNative(mNativeDictDirectBuffer,
TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER);
}
mDicTypeId = dicTypeId;
}
private native int openNative(ByteBuffer bb, 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, int[] nextLettersFrequencies, int nextLettersSize);
private native int getBigramsNative(int dict, char[] prevWord, int prevWordLength,
int[] inputCodes, int inputCodesLength, char[] outputChars, int[] frequencies,
int maxWordLength, int maxBigrams, int maxAlternatives);
private final void loadDictionary(InputStream[] is) {
try {
// merging separated dictionary into one if dictionary is separated
int total = 0;
for (int i = 0; i < is.length; i++) {
total += is[i].available();
}
mNativeDictDirectBuffer =
ByteBuffer.allocateDirect(total).order(ByteOrder.nativeOrder());
int got = 0;
for (int i = 0; i < is.length; i++) {
got += Channels.newChannel(is[i]).read(mNativeDictDirectBuffer);
}
if (got != total) {
Log.e(TAG, "Read " + got + " bytes, expected " + total);
} else {
mNativeDict = openNative(mNativeDictDirectBuffer,
TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER);
mDictLength = total;
}
if (mDictLength > 10000) Log.i(TAG, "Loaded dictionary, len=" + mDictLength);
} catch (IOException e) {
Log.w(TAG, "No available memory for binary dictionary");
} catch (UnsatisfiedLinkError e) {
Log.w(TAG, "Failed to load native dictionary", e);
} finally {
try {
if (is != null) {
for (int i = 0; i < is.length; i++) {
is[i].close();
}
}
} catch (IOException e) {
Log.w(TAG, "Failed to close input stream");
}
}
}
private final void loadDictionary(Context context, int[] resId) {
//Log.i(TAG, "loadDictionary, resId=" + (resId == null ? "null" : (resId.length > 0 ? String.format("0x%X", resId[0]) : "0")));
InputStream[] is = null;
try {
// merging separated dictionary into one if dictionary is separated
int total = 0;
is = new InputStream[resId.length];
for (int i = 0; i < resId.length; i++) {
is[i] = context.getResources().openRawResource(resId[i]);
total += is[i].available();
}
mNativeDictDirectBuffer =
ByteBuffer.allocateDirect(total).order(ByteOrder.nativeOrder());
int got = 0;
for (int i = 0; i < resId.length; i++) {
got += Channels.newChannel(is[i]).read(mNativeDictDirectBuffer);
}
if (got != total) {
Log.e(TAG, "Read " + got + " bytes, expected " + total);
} else {
mNativeDict = openNative(mNativeDictDirectBuffer,
TYPED_LETTER_MULTIPLIER, FULL_WORD_FREQ_MULTIPLIER);
mDictLength = total;
}
} catch (IOException e) {
Log.w(TAG, "No available memory for binary dictionary");
} finally {
try {
if (is != null) {
for (int i = 0; i < is.length; i++) {
is[i].close();
}
}
} catch (IOException e) {
Log.w(TAG, "Failed to close input stream");
}
}
}
@Override
public void getBigrams(final WordComposer codes, final CharSequence previousWord,
final WordCallback callback, int[] nextLettersFrequencies) {
char[] chars = previousWord.toString().toCharArray();
Arrays.fill(mOutputChars_bigrams, (char) 0);
Arrays.fill(mFrequencies_bigrams, 0);
int codesSize = codes.size();
Arrays.fill(mInputCodes, -1);
int[] alternatives = codes.getCodesAt(0);
System.arraycopy(alternatives, 0, mInputCodes, 0,
Math.min(alternatives.length, MAX_ALTERNATIVES));
int count = getBigramsNative(mNativeDict, chars, chars.length, mInputCodes, codesSize,
mOutputChars_bigrams, mFrequencies_bigrams, MAX_WORD_LENGTH, MAX_BIGRAMS,
MAX_ALTERNATIVES);
for (int j = 0; j < count; j++) {
if (mFrequencies_bigrams[j] < 1) break;
int start = j * MAX_WORD_LENGTH;
int len = 0;
while (mOutputChars_bigrams[start + len] != 0) {
len++;
}
if (len > 0) {
callback.addWord(mOutputChars_bigrams, start, len, mFrequencies_bigrams[j],
mDicTypeId, DataType.BIGRAM);
}
}
}
@Override
public void getWords(final WordComposer codes, final WordCallback callback,
int[] nextLettersFrequencies) {
final int codesSize = codes.size();
// Won't 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,
nextLettersFrequencies,
nextLettersFrequencies != null ? nextLettersFrequencies.length : 0);
// 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,
null, 0);
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], mDicTypeId,
DataType.UNIGRAM);
}
}
}
@Override
public boolean isValidWord(CharSequence word) {
if (word == null) return false;
char[] chars = word.toString().toCharArray();
return isValidWordNative(mNativeDict, chars, chars.length);
}
public int getSize() {
return mDictLength; // This value is initialized on the call to openNative()
}
@Override
public synchronized void close() {
if (mNativeDict != 0) {
closeNative(mNativeDict);
mNativeDict = 0;
}
}
@Override
protected void finalize() throws Throwable {
close();
super.finalize();
}
}