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70 lines
2.4 KiB
70 lines
2.4 KiB
/* |
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* Copyright (C) 2017 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 LIBTEXTCLASSIFIER_SMARTSELECT_TOKENIZER_H_ |
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#define LIBTEXTCLASSIFIER_SMARTSELECT_TOKENIZER_H_ |
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#include <string> |
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#include <vector> |
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#include "smartselect/tokenizer.pb.h" |
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#include "smartselect/types.h" |
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#include "util/base/integral_types.h" |
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namespace libtextclassifier { |
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// Tokenizer splits the input string into a sequence of tokens, according to the |
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// configuration. |
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class Tokenizer { |
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public: |
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explicit Tokenizer( |
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const std::vector<TokenizationCodepointRange>& codepoint_range_configs) { |
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PrepareTokenizationCodepointRanges(codepoint_range_configs); |
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} |
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// Tokenizes the input string using the selected tokenization method. |
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std::vector<Token> Tokenize(const std::string& utf8_text) const; |
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protected: |
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// Represents a codepoint range [start, end) with its role for tokenization. |
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struct CodepointRange { |
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int32 start; |
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int32 end; |
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TokenizationCodepointRange::Role role; |
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CodepointRange(int32 arg_start, int32 arg_end, |
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TokenizationCodepointRange::Role arg_role) |
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: start(arg_start), end(arg_end), role(arg_role) {} |
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}; |
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// Prepares tokenization codepoint ranges for use in tokenization. |
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void PrepareTokenizationCodepointRanges( |
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const std::vector<TokenizationCodepointRange>& codepoint_range_configs); |
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// Finds the tokenization role for given codepoint. |
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// If the character is not found returns DEFAULT_ROLE. |
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// Internally uses binary search so should be O(log(# of codepoint_ranges)). |
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TokenizationCodepointRange::Role FindTokenizationRole(int codepoint) const; |
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private: |
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// Codepoint ranges that determine how different codepoints are tokenized. |
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// The ranges must not overlap. |
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std::vector<CodepointRange> codepoint_ranges_; |
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}; |
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} // namespace libtextclassifier |
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#endif // LIBTEXTCLASSIFIER_SMARTSELECT_TOKENIZER_H_
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