BinaryDictionary.java revision e7a2512aa3666e1b891dc7dfc5a0cb28fd66bea9 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5 * use this file except in compliance with the License. You may obtain a copy of
6 * the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations under
14 * the License.
15 */
16
17package com.android.inputmethod.latin;
18
19import com.android.inputmethod.keyboard.Keyboard;
20import com.android.inputmethod.keyboard.KeyboardSwitcher;
21import com.android.inputmethod.keyboard.ProximityInfo;
22
23import android.content.Context;
24import android.content.res.AssetFileDescriptor;
25import android.util.Log;
26
27import java.io.File;
28import java.util.Arrays;
29
30/**
31 * Implements a static, compacted, binary dictionary of standard words.
32 */
33public class BinaryDictionary extends Dictionary {
34
35    /**
36     * There is difference between what java and native code can handle.
37     * This value should only be used in BinaryDictionary.java
38     * It is necessary to keep it at this value because some languages e.g. German have
39     * really long words.
40     */
41    public static final int MAX_WORD_LENGTH = 48;
42    public static final int MAX_WORDS = 18;
43
44    private static final String TAG = "BinaryDictionary";
45    private static final int MAX_PROXIMITY_CHARS_SIZE = ProximityInfo.MAX_PROXIMITY_CHARS_SIZE;
46    private static final int MAX_BIGRAMS = 60;
47
48    private static final int TYPED_LETTER_MULTIPLIER = 2;
49
50    private static final BinaryDictionary sInstance = new BinaryDictionary();
51    private int mDicTypeId;
52    private int mNativeDict;
53    private long mDictLength;
54    private final int[] mInputCodes = new int[MAX_WORD_LENGTH * MAX_PROXIMITY_CHARS_SIZE];
55    private final char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_WORDS];
56    private final char[] mOutputChars_bigrams = new char[MAX_WORD_LENGTH * MAX_BIGRAMS];
57    private final int[] mScores = new int[MAX_WORDS];
58    private final int[] mBigramScores = new int[MAX_BIGRAMS];
59
60    private final KeyboardSwitcher mKeyboardSwitcher = KeyboardSwitcher.getInstance();
61    private final SubtypeSwitcher mSubtypeSwitcher = SubtypeSwitcher.getInstance();
62
63    private static class Flags {
64        private static class FlagEntry {
65            public final String mName;
66            public final int mValue;
67            public FlagEntry(String name, int value) {
68                mName = name;
69                mValue = value;
70            }
71        }
72        public static final FlagEntry[] ALL_FLAGS = {
73            // Here should reside all flags that trigger some special processing
74            // These *must* match the definition in UnigramDictionary enum in
75            // unigram_dictionary.h so please update both at the same time.
76            new FlagEntry("requiresGermanUmlautProcessing", 0x1)
77        };
78    }
79    private int mFlags = 0;
80
81    private BinaryDictionary() {
82    }
83
84    /**
85     * Initialize a dictionary from a raw resource file
86     * @param context application context for reading resources
87     * @param resId the resource containing the raw binary dictionary
88     * @return initialized instance of BinaryDictionary
89     */
90    public static BinaryDictionary initDictionary(Context context, int resId, int dicTypeId) {
91        synchronized (sInstance) {
92            sInstance.closeInternal();
93            try {
94                final AssetFileDescriptor afd = context.getResources().openRawResourceFd(resId);
95                if (afd == null) {
96                    Log.e(TAG, "Found the resource but it is compressed. resId=" + resId);
97                    return null;
98                }
99                final String sourceDir = context.getApplicationInfo().sourceDir;
100                final File packagePath = new File(sourceDir);
101                // TODO: Come up with a way to handle a directory.
102                if (!packagePath.isFile()) {
103                    Log.e(TAG, "sourceDir is not a file: " + sourceDir);
104                    return null;
105                }
106                sInstance.loadDictionary(sourceDir, afd.getStartOffset(), afd.getLength());
107                sInstance.mDicTypeId = dicTypeId;
108            } catch (android.content.res.Resources.NotFoundException e) {
109                Log.e(TAG, "Could not find the resource. resId=" + resId);
110                return null;
111            }
112        }
113        sInstance.initFlags();
114        return sInstance;
115    }
116
117    /* package for test */ static BinaryDictionary initDictionary(File dictionary, long startOffset,
118            long length, int dicTypeId) {
119        synchronized (sInstance) {
120            sInstance.closeInternal();
121            if (dictionary.isFile()) {
122                sInstance.loadDictionary(dictionary.getAbsolutePath(), startOffset, length);
123                sInstance.mDicTypeId = dicTypeId;
124            } else {
125                Log.e(TAG, "Could not find the file. path=" + dictionary.getAbsolutePath());
126                return null;
127            }
128        }
129        return sInstance;
130    }
131
132    private void initFlags() {
133        int flags = 0;
134        for (Flags.FlagEntry entry : Flags.ALL_FLAGS) {
135            if (mSubtypeSwitcher.currentSubtypeContainsExtraValueKey(entry.mName))
136                flags |= entry.mValue;
137        }
138        mFlags = flags;
139    }
140
141    static {
142        Utils.loadNativeLibrary();
143    }
144
145    private native int openNative(String sourceDir, long dictOffset, long dictSize,
146            int typedLetterMultiplier, int fullWordMultiplier, int maxWordLength,
147            int maxWords, int maxAlternatives);
148    private native void closeNative(int dict);
149    private native boolean isValidWordNative(int nativeData, char[] word, int wordLength);
150    private native int getSuggestionsNative(int dict, int proximityInfo, int[] xCoordinates,
151            int[] yCoordinates, int[] inputCodes, int codesSize, int flags, char[] outputChars,
152            int[] scores);
153    private native int getBigramsNative(int dict, char[] prevWord, int prevWordLength,
154            int[] inputCodes, int inputCodesLength, char[] outputChars, int[] scores,
155            int maxWordLength, int maxBigrams, int maxAlternatives);
156
157    private final void loadDictionary(String path, long startOffset, long length) {
158        mNativeDict = openNative(path, startOffset, length,
159                    TYPED_LETTER_MULTIPLIER, FULL_WORD_SCORE_MULTIPLIER,
160                    MAX_WORD_LENGTH, MAX_WORDS, MAX_PROXIMITY_CHARS_SIZE);
161        mDictLength = length;
162    }
163
164    @Override
165    public void getBigrams(final WordComposer codes, final CharSequence previousWord,
166            final WordCallback callback) {
167        if (mNativeDict == 0) return;
168
169        char[] chars = previousWord.toString().toCharArray();
170        Arrays.fill(mOutputChars_bigrams, (char) 0);
171        Arrays.fill(mBigramScores, 0);
172
173        int codesSize = codes.size();
174        Arrays.fill(mInputCodes, -1);
175        int[] alternatives = codes.getCodesAt(0);
176        System.arraycopy(alternatives, 0, mInputCodes, 0,
177                Math.min(alternatives.length, MAX_PROXIMITY_CHARS_SIZE));
178
179        int count = getBigramsNative(mNativeDict, chars, chars.length, mInputCodes, codesSize,
180                mOutputChars_bigrams, mBigramScores, MAX_WORD_LENGTH, MAX_BIGRAMS,
181                MAX_PROXIMITY_CHARS_SIZE);
182
183        for (int j = 0; j < count; ++j) {
184            if (mBigramScores[j] < 1) break;
185            final int start = j * MAX_WORD_LENGTH;
186            int len = 0;
187            while (len <  MAX_WORD_LENGTH && mOutputChars_bigrams[start + len] != 0) {
188                ++len;
189            }
190            if (len > 0) {
191                callback.addWord(mOutputChars_bigrams, start, len, mBigramScores[j],
192                        mDicTypeId, DataType.BIGRAM);
193            }
194        }
195    }
196
197    @Override
198    public void getWords(final WordComposer codes, final WordCallback callback) {
199        final int count = getSuggestions(codes, mKeyboardSwitcher.getLatinKeyboard(),
200                mOutputChars, mScores);
201
202        for (int j = 0; j < count; ++j) {
203            if (mScores[j] < 1) break;
204            final int start = j * MAX_WORD_LENGTH;
205            int len = 0;
206            while (len < MAX_WORD_LENGTH && mOutputChars[start + len] != 0) {
207                ++len;
208            }
209            if (len > 0) {
210                callback.addWord(mOutputChars, start, len, mScores[j], mDicTypeId,
211                        DataType.UNIGRAM);
212            }
213        }
214    }
215
216    /* package for test */ boolean isValidDictionary() {
217        return mNativeDict != 0;
218    }
219
220    /* package for test */ int getSuggestions(final WordComposer codes, final Keyboard keyboard,
221            char[] outputChars, int[] scores) {
222        if (!isValidDictionary()) return -1;
223
224        final int codesSize = codes.size();
225        // Won't deal with really long words.
226        if (codesSize > MAX_WORD_LENGTH - 1) return -1;
227
228        Arrays.fill(mInputCodes, WordComposer.NOT_A_CODE);
229        for (int i = 0; i < codesSize; i++) {
230            int[] alternatives = codes.getCodesAt(i);
231            System.arraycopy(alternatives, 0, mInputCodes, i * MAX_PROXIMITY_CHARS_SIZE,
232                    Math.min(alternatives.length, MAX_PROXIMITY_CHARS_SIZE));
233        }
234        Arrays.fill(outputChars, (char) 0);
235        Arrays.fill(scores, 0);
236
237        return getSuggestionsNative(
238                mNativeDict, keyboard.getProximityInfo(),
239                codes.getXCoordinates(), codes.getYCoordinates(), mInputCodes, codesSize,
240                mFlags, outputChars, scores);
241    }
242
243    @Override
244    public boolean isValidWord(CharSequence word) {
245        if (word == null) return false;
246        char[] chars = word.toString().toCharArray();
247        return isValidWordNative(mNativeDict, chars, chars.length);
248    }
249
250    public long getSize() {
251        return mDictLength; // This value is initialized in loadDictionary()
252    }
253
254    @Override
255    public synchronized void close() {
256        closeInternal();
257    }
258
259    private void closeInternal() {
260        if (mNativeDict != 0) {
261            closeNative(mNativeDict);
262            mNativeDict = 0;
263            mDictLength = 0;
264        }
265    }
266
267    @Override
268    protected void finalize() throws Throwable {
269        try {
270            closeInternal();
271        } finally {
272            super.finalize();
273        }
274    }
275}
276