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_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONST_EVAL_H_ 18 #define LIBTEXTCLASSIFIER_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONST_EVAL_H_ 19 20 #include "utils/base/arena.h" 21 #include "utils/grammar/semantics/eval-context.h" 22 #include "utils/grammar/semantics/evaluator.h" 23 #include "utils/grammar/semantics/expression_generated.h" 24 #include "utils/grammar/semantics/value.h" 25 26 namespace libtextclassifier3::grammar { 27 28 // Returns a constant value of a given type. 29 class ConstEvaluator : public SemanticExpressionEvaluator { 30 public: ConstEvaluator(const reflection::Schema * semantic_values_schema)31 explicit ConstEvaluator(const reflection::Schema* semantic_values_schema) 32 : semantic_values_schema_(semantic_values_schema) {} 33 Apply(const EvalContext &,const SemanticExpression * expression,UnsafeArena * arena)34 StatusOr<const SemanticValue*> Apply(const EvalContext&, 35 const SemanticExpression* expression, 36 UnsafeArena* arena) const override { 37 TC3_DCHECK_EQ(expression->expression_type(), 38 SemanticExpression_::Expression_ConstValueExpression); 39 const ConstValueExpression* const_value_expression = 40 expression->expression_as_ConstValueExpression(); 41 const reflection::BaseType base_type = 42 static_cast<reflection::BaseType>(const_value_expression->base_type()); 43 const StringPiece data = StringPiece( 44 reinterpret_cast<const char*>(const_value_expression->value()->data()), 45 const_value_expression->value()->size()); 46 47 if (base_type == reflection::BaseType::Obj) { 48 // Resolve the object type. 49 const int type_id = const_value_expression->type(); 50 if (type_id < 0 || 51 type_id >= semantic_values_schema_->objects()->size()) { 52 return Status(StatusCode::INVALID_ARGUMENT, "Invalid type."); 53 } 54 return SemanticValue::Create(semantic_values_schema_->objects()->Get( 55 const_value_expression->type()), 56 data, arena); 57 } else { 58 return SemanticValue::Create(base_type, data, arena); 59 } 60 } 61 62 private: 63 const reflection::Schema* semantic_values_schema_; 64 }; 65 66 } // namespace libtextclassifier3::grammar 67 68 #endif // LIBTEXTCLASSIFIER_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONST_EVAL_H_ 69