| /* |
| * Copyright (C) 2018 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 LIBTEXTCLASSIFIER_ACTIONS_NGRAM_MODEL_H_ |
| #define LIBTEXTCLASSIFIER_ACTIONS_NGRAM_MODEL_H_ |
| |
| #include <memory> |
| |
| #include "actions/actions_model_generated.h" |
| #include "actions/sensitive-classifier-base.h" |
| #include "actions/types.h" |
| #include "utils/tokenizer.h" |
| #include "utils/utf8/unicodetext.h" |
| #include "utils/utf8/unilib.h" |
| |
| namespace libtextclassifier3 { |
| |
| class NGramSensitiveModel : public SensitiveTopicModelBase { |
| public: |
| static std::unique_ptr<NGramSensitiveModel> Create( |
| const UniLib* unilib, const NGramLinearRegressionModel* model, |
| const Tokenizer* tokenizer); |
| |
| // Evaluates an n-gram linear regression model, and tests against the |
| // threshold. Returns true in case of a positive classification. The caller |
| // may also optionally query the score. |
| std::pair<bool, float> Eval(const UnicodeText& text) const override; |
| |
| // Evaluates an n-gram linear regression model against all messages in a |
| // conversation and returns true in case of any positive classification. |
| std::pair<bool, float> EvalConversation(const Conversation& conversation, |
| int num_messages) const override; |
| |
| // Exposed for testing only. |
| static uint64 GetNumSkipGrams(int num_tokens, int max_ngram_length, |
| int max_skips); |
| |
| private: |
| explicit NGramSensitiveModel(const UniLib* unilib, |
| const NGramLinearRegressionModel* model, |
| const Tokenizer* tokenizer); |
| |
| // Returns the (begin,end] range of n-grams where the first hashed token |
| // matches the given value. |
| std::pair<int, int> GetFirstTokenMatches(uint32 token_hash) const; |
| |
| // Returns whether a given n-gram matches the token stream. |
| bool IsNGramMatch(const uint32* tokens, size_t num_tokens, |
| const uint32* ngram_tokens, size_t num_ngram_tokens, |
| int max_skips) const; |
| |
| const NGramLinearRegressionModel* model_; |
| const Tokenizer* tokenizer_; |
| std::unique_ptr<Tokenizer> owned_tokenizer_; |
| }; |
| |
| } // namespace libtextclassifier3 |
| |
| #endif // LIBTEXTCLASSIFIER_ACTIONS_NGRAM_MODEL_H_ |