85 lines
3.3 KiB
C++
85 lines
3.3 KiB
C++
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef LATINIME_MULTI_BIGRAM_MAP_H
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#define LATINIME_MULTI_BIGRAM_MAP_H
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#include <cstddef>
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#include <unordered_map>
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#include "defines.h"
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#include "dictionary/interface/dictionary_structure_with_buffer_policy.h"
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#include "dictionary/interface/ngram_listener.h"
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#include "dictionary/utils/binary_dictionary_bigrams_iterator.h"
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#include "dictionary/utils/bloom_filter.h"
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#include "utils/int_array_view.h"
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namespace latinime {
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// Class for caching bigram maps for multiple previous word contexts. This is useful since the
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// algorithm needs to look up the set of bigrams for every word pair that occurs in every
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// multi-word suggestion.
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class MultiBigramMap {
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public:
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MultiBigramMap() : mBigramMaps() {}
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~MultiBigramMap() {}
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// Look up the bigram probability for the given word pair from the cached bigram maps.
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// Also caches the bigrams if there is space remaining and they have not been cached already.
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int getBigramProbability(const DictionaryStructureWithBufferPolicy *const structurePolicy,
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const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability);
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void clear() {
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mBigramMaps.clear();
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}
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private:
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DISALLOW_COPY_AND_ASSIGN(MultiBigramMap);
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class BigramMap : public NgramListener {
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public:
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BigramMap() : mBigramMap(DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP), mBloomFilter() {}
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// Copy constructor needed for std::unordered_map.
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BigramMap(const BigramMap &bigramMap)
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: mBigramMap(bigramMap.mBigramMap), mBloomFilter(bigramMap.mBloomFilter) {}
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virtual ~BigramMap() {}
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void init(const DictionaryStructureWithBufferPolicy *const structurePolicy,
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const WordIdArrayView prevWordIds);
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int getBigramProbability(
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const DictionaryStructureWithBufferPolicy *const structurePolicy,
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const int nextWordId, const int unigramProbability) const;
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virtual void onVisitEntry(const int ngramProbability, const int targetWordId);
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private:
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static const int DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP;
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std::unordered_map<int, int> mBigramMap;
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BloomFilter mBloomFilter;
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};
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void addBigramsForWord(const DictionaryStructureWithBufferPolicy *const structurePolicy,
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const WordIdArrayView prevWordIds);
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int readBigramProbabilityFromBinaryDictionary(
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const DictionaryStructureWithBufferPolicy *const structurePolicy,
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const WordIdArrayView prevWordIds, const int nextWordId, const int unigramProbability);
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static const size_t MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP;
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std::unordered_map<int, BigramMap> mBigramMaps;
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};
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} // namespace latinime
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#endif // LATINIME_MULTI_BIGRAM_MAP_H
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