89 lines
3.2 KiB
C++
89 lines
3.2 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 <cstring>
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#include <stdint.h>
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#include "defines.h"
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#include "binary_format.h"
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#include "hash_map_compat.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 uint8_t *const dicRoot, const int wordPosition,
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const int nextWordPosition, const int unigramProbability) {
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hash_map_compat<int, BigramMap>::const_iterator mapPosition =
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mBigramMaps.find(wordPosition);
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if (mapPosition != mBigramMaps.end()) {
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return mapPosition->second.getBigramProbability(nextWordPosition, unigramProbability);
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}
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if (mBigramMaps.size() < MAX_CACHED_PREV_WORDS_IN_BIGRAM_MAP) {
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addBigramsForWordPosition(dicRoot, wordPosition);
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return mBigramMaps[wordPosition].getBigramProbability(
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nextWordPosition, unigramProbability);
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}
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return BinaryFormat::getBigramProbability(
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dicRoot, wordPosition, nextWordPosition, unigramProbability);
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}
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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 {
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public:
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BigramMap() : mBigramMap(DEFAULT_HASH_MAP_SIZE_FOR_EACH_BIGRAM_MAP) {}
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~BigramMap() {}
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void init(const uint8_t *const dicRoot, int position) {
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BinaryFormat::fillBigramProbabilityToHashMap(dicRoot, position, &mBigramMap);
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}
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inline int getBigramProbability(const int nextWordPosition, const int unigramProbability)
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const {
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return BinaryFormat::getBigramProbabilityFromHashMap(
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nextWordPosition, &mBigramMap, unigramProbability);
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}
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private:
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// Note: Default copy constructor needed for use in hash_map.
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hash_map_compat<int, int> mBigramMap;
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};
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void addBigramsForWordPosition(const uint8_t *const dicRoot, const int position) {
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mBigramMaps[position].init(dicRoot, position);
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}
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hash_map_compat<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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