1/*
2 * Copyright (C) 2010 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
17#ifndef LATINIME_BIGRAM_DICTIONARY_H
18#define LATINIME_BIGRAM_DICTIONARY_H
19
20#include <map>
21#include <stdint.h>
22
23#include "defines.h"
24
25namespace latinime {
26
27class BigramDictionary {
28 public:
29    BigramDictionary(const unsigned char *dict, int maxWordLength, int maxPredictions);
30    int getBigrams(const int32_t *word, int length, int *inputCodes, int codesSize,
31            unsigned short *outWords, int *frequencies, int *outputTypes) const;
32    void fillBigramAddressToFrequencyMapAndFilter(const int32_t *prevWord, const int prevWordLength,
33            std::map<int, int> *map, uint8_t *filter) const;
34    bool isValidBigram(const int32_t *word1, int length1, const int32_t *word2, int length2) const;
35    ~BigramDictionary();
36 private:
37    DISALLOW_IMPLICIT_CONSTRUCTORS(BigramDictionary);
38    bool addWordBigram(unsigned short *word, int length, int frequency,
39            int *bigramFreq, unsigned short *bigramChars, int *outputTypes) const;
40    int getBigramAddress(int *pos, bool advance);
41    int getBigramFreq(int *pos);
42    void searchForTerminalNode(int addressLookingFor, int frequency);
43    bool getFirstBitOfByte(int *pos) { return (DICT[*pos] & 0x80) > 0; }
44    bool getSecondBitOfByte(int *pos) { return (DICT[*pos] & 0x40) > 0; }
45    bool checkFirstCharacter(unsigned short *word, int *inputCodes) const;
46    int getBigramListPositionForWord(const int32_t *prevWord, const int prevWordLength,
47            const bool forceLowerCaseSearch) const;
48
49    const unsigned char *DICT;
50    const int MAX_WORD_LENGTH;
51    const int MAX_PREDICTIONS;
52    // TODO: Re-implement proximity correction for bigram correction
53    static const int MAX_ALTERNATIVES = 1;
54};
55} // namespace latinime
56#endif // LATINIME_BIGRAM_DICTIONARY_H
57