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1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef LIBTEXTCLASSIFIER_ANNOTATOR_GRAMMAR_GRAMMAR_ANNOTATOR_H_
18 #define LIBTEXTCLASSIFIER_ANNOTATOR_GRAMMAR_GRAMMAR_ANNOTATOR_H_
19 
20 #include <vector>
21 
22 #include "annotator/model_generated.h"
23 #include "annotator/types.h"
24 #include "utils/flatbuffers/mutable.h"
25 #include "utils/grammar/analyzer.h"
26 #include "utils/grammar/evaluated-derivation.h"
27 #include "utils/grammar/text-context.h"
28 #include "utils/i18n/locale.h"
29 #include "utils/tokenizer.h"
30 #include "utils/utf8/unicodetext.h"
31 #include "utils/utf8/unilib.h"
32 
33 namespace libtextclassifier3 {
34 
35 // Grammar backed annotator.
36 class GrammarAnnotator {
37  public:
38   explicit GrammarAnnotator(
39       const UniLib* unilib, const GrammarModel* model,
40       const MutableFlatbufferBuilder* entity_data_builder);
41 
42   // Annotates a given text.
43   // Returns true if the text was successfully annotated.
44   bool Annotate(const std::vector<Locale>& locales, const UnicodeText& text,
45                 std::vector<AnnotatedSpan>* result) const;
46 
47   // Classifies a span in a text.
48   // Returns true if the span was classified by a grammar rule.
49   bool ClassifyText(const std::vector<Locale>& locales, const UnicodeText& text,
50                     const CodepointSpan& selection,
51                     ClassificationResult* classification_result) const;
52 
53   // Suggests text selections in a text.
54   // Returns true if a span was suggested by a grammar rule.
55   bool SuggestSelection(const std::vector<Locale>& locales,
56                         const UnicodeText& text, const CodepointSpan& selection,
57                         AnnotatedSpan* result) const;
58 
59  private:
60   // Filters out derivations that do not overlap with a reference span.
61   std::vector<grammar::Derivation> OverlappingDerivations(
62       const CodepointSpan& selection,
63       const std::vector<grammar::Derivation>& derivations,
64       const bool only_exact_overlap) const;
65 
66   // Fills out an annotated span from a grammar match result.
67   bool InstantiateAnnotatedSpanFromDerivation(
68       const grammar::TextContext& input_context,
69       const grammar::ParseTree* parse_tree,
70       const GrammarModel_::RuleClassificationResult* interpretation,
71       AnnotatedSpan* result) const;
72 
73   // Instantiates a classification result from a rule match.
74   bool InstantiateClassificationFromDerivation(
75       const grammar::TextContext& input_context,
76       const grammar::ParseTree* parse_tree,
77       const GrammarModel_::RuleClassificationResult* interpretation,
78       ClassificationResult* classification) const;
79 
80   const UniLib& unilib_;
81   const GrammarModel* model_;
82   const Tokenizer tokenizer_;
83   const MutableFlatbufferBuilder* entity_data_builder_;
84   const grammar::Analyzer analyzer_;
85 };
86 
87 }  // namespace libtextclassifier3
88 
89 #endif  // LIBTEXTCLASSIFIER_ANNOTATOR_GRAMMAR_GRAMMAR_ANNOTATOR_H_
90