LatinIME/native/jni/src/bigram_dictionary.h
Jean Chalard 1ff8dc47be Fill up a map of bigram addresses for lookup.
We don't want to do a linear search on each terminal when there
may be 100+ bigrams for a given word because that would be
disastrous for performance. Also, we need to resolve each bigram
address anyway.
This change resolves the addresses at first and puts them in a
balanced tree so that lookup will be O(log(n)).

Bug: 6313806
Change-Id: Ibf088035870b9acb41e948f0ab7af4726f2cee24
2012-05-02 17:50:44 +09:00

59 lines
2.1 KiB
C++

/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LATINIME_BIGRAM_DICTIONARY_H
#define LATINIME_BIGRAM_DICTIONARY_H
#include <map>
#include <stdint.h>
namespace latinime {
class Dictionary;
class BigramDictionary {
public:
BigramDictionary(const unsigned char *dict, int maxWordLength, Dictionary *parentDictionary);
int getBigrams(const int32_t *word, int length, int *codes, int codesSize,
unsigned short *outWords, int *frequencies, int maxWordLength, int maxBigrams);
int getBigramListPositionForWord(const int32_t *prevWord, const int prevWordLength);
void fillBigramAddressToFrequencyMap(const int32_t *prevWord, const int prevWordLength,
std::map<int, int> *map);
~BigramDictionary();
private:
bool addWordBigram(unsigned short *word, int length, int frequency);
int getBigramAddress(int *pos, bool advance);
int getBigramFreq(int *pos);
void searchForTerminalNode(int addressLookingFor, int frequency);
bool getFirstBitOfByte(int *pos) { return (DICT[*pos] & 0x80) > 0; }
bool getSecondBitOfByte(int *pos) { return (DICT[*pos] & 0x40) > 0; }
bool checkFirstCharacter(unsigned short *word);
const unsigned char *DICT;
const int MAX_WORD_LENGTH;
// TODO: Re-implement proximity correction for bigram correction
static const int MAX_ALTERNATIVES = 1;
Dictionary *mParentDictionary;
int *mBigramFreq;
int mMaxBigrams;
unsigned short *mBigramChars;
int *mInputCodes;
int mInputLength;
};
} // namespace latinime
#endif // LATINIME_BIGRAM_DICTIONARY_H