BinaryDictionary.java revision 18d76afa911f5b236901eed6eba48a801dfdaafa
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 android.content.Context; 20import android.text.TextUtils; 21 22import com.android.inputmethod.keyboard.ProximityInfo; 23import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo; 24 25import java.util.ArrayList; 26import java.util.Arrays; 27import java.util.Locale; 28 29/** 30 * Implements a static, compacted, binary dictionary of standard words. 31 */ 32public class BinaryDictionary extends Dictionary { 33 34 public static final String DICTIONARY_PACK_AUTHORITY = 35 "com.android.inputmethod.latin.dictionarypack"; 36 37 /** 38 * There is a difference between what java and native code can handle. 39 * This value should only be used in BinaryDictionary.java 40 * It is necessary to keep it at this value because some languages e.g. German have 41 * really long words. 42 */ 43 public static final int MAX_WORD_LENGTH = 48; 44 public static final int MAX_WORDS = 18; 45 public static final int MAX_SPACES = 16; 46 47 private static final String TAG = "BinaryDictionary"; 48 private static final int MAX_PREDICTIONS = 60; 49 private static final int MAX_RESULTS = Math.max(MAX_PREDICTIONS, MAX_WORDS); 50 51 private static final int TYPED_LETTER_MULTIPLIER = 2; 52 53 private long mNativeDict; 54 private final int[] mInputCodes = new int[MAX_WORD_LENGTH]; 55 private final char[] mOutputChars = new char[MAX_WORD_LENGTH * MAX_RESULTS]; 56 private final int[] mSpaceIndices = new int[MAX_SPACES]; 57 private final int[] mOutputScores = new int[MAX_RESULTS]; 58 59 private final boolean mUseFullEditDistance; 60 61 /** 62 * Constructor for the binary dictionary. This is supposed to be called from the 63 * dictionary factory. 64 * All implementations should pass null into flagArray, except for testing purposes. 65 * @param context the context to access the environment from. 66 * @param filename the name of the file to read through native code. 67 * @param offset the offset of the dictionary data within the file. 68 * @param length the length of the binary data. 69 * @param useFullEditDistance whether to use the full edit distance in suggestions 70 * @param dictType the dictionary type, as a human-readable string 71 */ 72 public BinaryDictionary(final Context context, 73 final String filename, final long offset, final long length, 74 final boolean useFullEditDistance, final Locale locale, final String dictType) { 75 super(dictType); 76 mUseFullEditDistance = useFullEditDistance; 77 loadDictionary(filename, offset, length); 78 } 79 80 static { 81 JniUtils.loadNativeLibrary(); 82 } 83 84 private native long openNative(String sourceDir, long dictOffset, long dictSize, 85 int typedLetterMultiplier, int fullWordMultiplier, int maxWordLength, int maxWords, 86 int maxPredictions); 87 private native void closeNative(long dict); 88 private native int getFrequencyNative(long dict, int[] word, int wordLength); 89 private native boolean isValidBigramNative(long dict, int[] word1, int[] word2); 90 private native int getSuggestionsNative(long dict, long proximityInfo, int[] xCoordinates, 91 int[] yCoordinates, int[] times, int[] pointerIds, int[] inputCodes, int codesSize, 92 int commitPoint, boolean isGesture, 93 int[] prevWordCodePointArray, boolean useFullEditDistance, char[] outputChars, 94 int[] scores, int[] outputIndices); 95 private static native float calcNormalizedScoreNative( 96 char[] before, int beforeLength, char[] after, int afterLength, int score); 97 private static native int editDistanceNative( 98 char[] before, int beforeLength, char[] after, int afterLength); 99 100 private final void loadDictionary(String path, long startOffset, long length) { 101 mNativeDict = openNative(path, startOffset, length, TYPED_LETTER_MULTIPLIER, 102 FULL_WORD_SCORE_MULTIPLIER, MAX_WORD_LENGTH, MAX_WORDS, MAX_PREDICTIONS); 103 } 104 105 @Override 106 public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer composer, 107 final CharSequence prevWord, final ProximityInfo proximityInfo) { 108 if (!isValidDictionary()) return null; 109 Arrays.fill(mInputCodes, WordComposer.NOT_A_CODE); 110 Arrays.fill(mOutputChars, (char) 0); 111 Arrays.fill(mOutputScores, 0); 112 // TODO: toLowerCase in the native code 113 final int[] prevWordCodePointArray = (null == prevWord) 114 ? null : StringUtils.toCodePointArray(prevWord.toString()); 115 final int composerSize = composer.size(); 116 117 final boolean isGesture = composer.isBatchMode(); 118 if (composerSize <= 1 || !isGesture) { 119 if (composerSize > MAX_WORD_LENGTH - 1) return null; 120 for (int i = 0; i < composerSize; i++) { 121 mInputCodes[i] = composer.getCodeAt(i); 122 } 123 } 124 125 // TODO: move this test to native code. 126 if (composerSize <= 1 && TextUtils.isEmpty(prevWord)) return null; 127 final InputPointers ips = composer.getInputPointers(); 128 final int codesSize = isGesture ? ips.getPointerSize() : composerSize; 129 // proximityInfo and/or prevWordForBigrams may not be null. 130 final int tmpCount = getSuggestionsNative(mNativeDict, 131 proximityInfo.getNativeProximityInfo(), ips.getXCoordinates(), 132 ips.getYCoordinates(), ips.getTimes(), ips.getPointerIds(), 133 mInputCodes, codesSize, 0 /* unused */, isGesture, prevWordCodePointArray, 134 mUseFullEditDistance, mOutputChars, mOutputScores, mSpaceIndices); 135 final int count = Math.min(tmpCount, MAX_PREDICTIONS); 136 137 final ArrayList<SuggestedWordInfo> suggestions = new ArrayList<SuggestedWordInfo>(); 138 for (int j = 0; j < count; ++j) { 139 if (composerSize > 0 && mOutputScores[j] < 1) break; 140 final int start = j * MAX_WORD_LENGTH; 141 int len = 0; 142 while (len < MAX_WORD_LENGTH && mOutputChars[start + len] != 0) { 143 ++len; 144 } 145 if (len > 0) { 146 suggestions.add(new SuggestedWordInfo( 147 new String(mOutputChars, start, len), 148 mOutputScores[j], SuggestedWordInfo.KIND_CORRECTION, mDictType)); 149 } 150 } 151 return suggestions; 152 } 153 154 /* package for test */ boolean isValidDictionary() { 155 return mNativeDict != 0; 156 } 157 158 public static float calcNormalizedScore(String before, String after, int score) { 159 return calcNormalizedScoreNative(before.toCharArray(), before.length(), 160 after.toCharArray(), after.length(), score); 161 } 162 163 public static int editDistance(String before, String after) { 164 return editDistanceNative( 165 before.toCharArray(), before.length(), after.toCharArray(), after.length()); 166 } 167 168 @Override 169 public boolean isValidWord(CharSequence word) { 170 return getFrequency(word) >= 0; 171 } 172 173 @Override 174 public int getFrequency(CharSequence word) { 175 if (word == null) return -1; 176 int[] chars = StringUtils.toCodePointArray(word.toString()); 177 return getFrequencyNative(mNativeDict, chars, chars.length); 178 } 179 180 // TODO: Add a batch process version (isValidBigramMultiple?) to avoid excessive numbers of jni 181 // calls when checking for changes in an entire dictionary. 182 public boolean isValidBigram(CharSequence word1, CharSequence word2) { 183 if (TextUtils.isEmpty(word1) || TextUtils.isEmpty(word2)) return false; 184 int[] chars1 = StringUtils.toCodePointArray(word1.toString()); 185 int[] chars2 = StringUtils.toCodePointArray(word2.toString()); 186 return isValidBigramNative(mNativeDict, chars1, chars2); 187 } 188 189 @Override 190 public synchronized void close() { 191 closeInternal(); 192 } 193 194 private void closeInternal() { 195 if (mNativeDict != 0) { 196 closeNative(mNativeDict); 197 mNativeDict = 0; 198 } 199 } 200 201 @Override 202 protected void finalize() throws Throwable { 203 try { 204 closeInternal(); 205 } finally { 206 super.finalize(); 207 } 208 } 209} 210