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      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 
     25 namespace latinime {
     26 
     27 class Dictionary;
     28 class BigramDictionary {
     29  public:
     30     BigramDictionary(const unsigned char *dict, int maxWordLength, Dictionary *parentDictionary);
     31     int getBigrams(const int32_t *word, int length, int *codes, int codesSize,
     32             unsigned short *outWords, int *frequencies, int maxWordLength, int maxBigrams);
     33     int getBigramListPositionForWord(const int32_t *prevWord, const int prevWordLength);
     34     void fillBigramAddressToFrequencyMapAndFilter(const int32_t *prevWord, const int prevWordLength,
     35             std::map<int, int> *map, uint8_t *filter);
     36     bool isValidBigram(const int32_t *word1, int length1, const int32_t *word2, int length2);
     37     ~BigramDictionary();
     38  private:
     39     bool addWordBigram(unsigned short *word, int length, int frequency);
     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);
     46 
     47     const unsigned char *DICT;
     48     const int MAX_WORD_LENGTH;
     49     // TODO: Re-implement proximity correction for bigram correction
     50     static const int MAX_ALTERNATIVES = 1;
     51 
     52     Dictionary *mParentDictionary;
     53     int *mBigramFreq;
     54     int mMaxBigrams;
     55     unsigned short *mBigramChars;
     56     int *mInputCodes;
     57     int mInputLength;
     58 };
     59 
     60 } // namespace latinime
     61 
     62 #endif // LATINIME_BIGRAM_DICTIONARY_H
     63