1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of 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,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.inputmethod.latin.makedict;
18
19import com.android.inputmethod.annotations.UsedForTesting;
20import com.android.inputmethod.latin.BinaryDictionary;
21import com.android.inputmethod.latin.common.FileUtils;
22
23import java.io.File;
24import java.io.FileNotFoundException;
25import java.io.IOException;
26import java.util.ArrayList;
27
28/**
29 * An implementation of binary dictionary decoder for version 4 binary dictionary.
30 */
31@UsedForTesting
32public class Ver4DictDecoder extends AbstractDictDecoder {
33    final File mDictDirectory;
34
35    @UsedForTesting
36    /* package */ Ver4DictDecoder(final File dictDirectory) {
37        mDictDirectory = dictDirectory;
38
39    }
40
41    @Override
42    public DictionaryHeader readHeader() throws IOException, UnsupportedFormatException {
43        // dictType is not being used in dicttool. Passing an empty string.
44        final BinaryDictionary binaryDictionary= new BinaryDictionary(
45              mDictDirectory.getAbsolutePath(), 0 /* offset */, 0 /* length */,
46              true /* useFullEditDistance */, null /* locale */,
47              "" /* dictType */, true /* isUpdatable */);
48        final DictionaryHeader header = binaryDictionary.getHeader();
49        binaryDictionary.close();
50        if (header == null) {
51            throw new IOException("Cannot read the dictionary header.");
52        }
53        return header;
54    }
55
56    @Override
57    public FusionDictionary readDictionaryBinary(final boolean deleteDictIfBroken)
58            throws FileNotFoundException, IOException, UnsupportedFormatException {
59        // dictType is not being used in dicttool. Passing an empty string.
60        final BinaryDictionary binaryDictionary = new BinaryDictionary(
61              mDictDirectory.getAbsolutePath(), 0 /* offset */, 0 /* length */,
62              true /* useFullEditDistance */, null /* locale */,
63              "" /* dictType */, true /* isUpdatable */);
64        final DictionaryHeader header = readHeader();
65        final FusionDictionary fusionDict =
66                new FusionDictionary(new FusionDictionary.PtNodeArray(), header.mDictionaryOptions);
67        int token = 0;
68        final ArrayList<WordProperty> wordProperties = new ArrayList<>();
69        do {
70            final BinaryDictionary.GetNextWordPropertyResult result =
71                    binaryDictionary.getNextWordProperty(token);
72            final WordProperty wordProperty = result.mWordProperty;
73            if (wordProperty == null) {
74                binaryDictionary.close();
75                if (deleteDictIfBroken) {
76                    FileUtils.deleteRecursively(mDictDirectory);
77                }
78                return null;
79            }
80            wordProperties.add(wordProperty);
81            token = result.mNextToken;
82        } while (token != 0);
83
84        // Insert unigrams into the fusion dictionary.
85        for (final WordProperty wordProperty : wordProperties) {
86            fusionDict.add(wordProperty.mWord, wordProperty.mProbabilityInfo,
87                    wordProperty.mIsNotAWord,
88                    wordProperty.mIsPossiblyOffensive);
89        }
90        // Insert bigrams into the fusion dictionary.
91        // TODO: Support ngrams.
92        for (final WordProperty wordProperty : wordProperties) {
93            if (!wordProperty.mHasNgrams) {
94                continue;
95            }
96            final String word0 = wordProperty.mWord;
97            for (final WeightedString bigram : wordProperty.getBigrams()) {
98                fusionDict.setBigram(word0, bigram.mWord, bigram.mProbabilityInfo);
99            }
100        }
101        binaryDictionary.close();
102        return fusionDict;
103    }
104}
105