| /* |
| * Copyright (C) 2013 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_MULTI_BIGRAM_MAP_H |
| #define LATINIME_MULTI_BIGRAM_MAP_H |
| |
| #include <cstddef> |
| #include <unordered_map> |
| |
| #include "defines.h" |
| #include "dictionary/interface/dictionary_structure_with_buffer_policy.h" |
| #include "dictionary/interface/ngram_listener.h" |
| #include "dictionary/utils/binary_dictionary_bigrams_iterator.h" |
| #include "dictionary/utils/bloom_filter.h" |
| #include "utils/int_array_view.h" |
| |
| namespace latinime { |
| |
| // Class for caching bigram maps for multiple previous word contexts. This is useful since the |
| // algorithm needs to look up the set of bigrams for every word pair that occurs in every |
| // multi-word suggestion. |
| class MultiBigramMap { |
| public: |
| MultiBigramMap() : mBigramMaps() {} |
| ~MultiBigramMap() {} |
| |
| // Look up the bigram probability for the given word pair from the cached bigram maps. |
| // Also caches the bigrams if there is space remaining and they have not been cached already. |
| int getBigramProbability(const DictionaryStructureWithBufferPolicy *const structurePolicy, |
| const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability); |
| |
| void clear() { |
| mBigramMaps.clear(); |
| } |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(MultiBigramMap); |
| |
| class BigramMap : public NgramListener { |
| public: |
| BigramMap() : mBigramMap(DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP), mBloomFilter() {} |
| // Copy constructor needed for std::unordered_map. |
| BigramMap(const BigramMap &bigramMap) |
| : mBigramMap(bigramMap.mBigramMap), mBloomFilter(bigramMap.mBloomFilter) {} |
| virtual ~BigramMap() {} |
| |
| void init(const DictionaryStructureWithBufferPolicy *const structurePolicy, |
| const WordIdArrayView prevWordIds); |
| int getBigramProbability( |
| const DictionaryStructureWithBufferPolicy *const structurePolicy, |
| const int nextWordId, const int unigramProbability) const; |
| virtual void onVisitEntry(const int ngramProbability, const int targetWordId); |
| |
| private: |
| static const int DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP; |
| std::unordered_map<int, int> mBigramMap; |
| BloomFilter mBloomFilter; |
| }; |
| |
| void addBigramsForWord(const DictionaryStructureWithBufferPolicy *const structurePolicy, |
| const WordIdArrayView prevWordIds); |
| |
| int readBigramProbabilityFromBinaryDictionary( |
| const DictionaryStructureWithBufferPolicy *const structurePolicy, |
| const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability); |
| |
| static const size_t MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP; |
| std::unordered_map<int, BigramMap> mBigramMaps; |
| }; |
| } // namespace latinime |
| #endif // LATINIME_MULTI_BIGRAM_MAP_H |