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      1 /* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
      2 
      3 Licensed under the Apache License, Version 2.0 (the "License");
      4 you may not use this file except in compliance with the License.
      5 You may obtain a copy of the License at
      6 
      7     http://www.apache.org/licenses/LICENSE-2.0
      8 
      9 Unless required by applicable law or agreed to in writing, software
     10 distributed under the License is distributed on an "AS IS" BASIS,
     11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 See the License for the specific language governing permissions and
     13 limitations under the License.
     14 ==============================================================================*/
     15 #ifndef TENSORFLOW_CONTRIB_LITE_TOCO_TFLITE_CUSTOM_OPERATOR_H_
     16 #define TENSORFLOW_CONTRIB_LITE_TOCO_TFLITE_CUSTOM_OPERATOR_H_
     17 
     18 #include "flatbuffers/flexbuffers.h"
     19 #include "absl/memory/memory.h"
     20 #include "tensorflow/contrib/lite/toco/tflite/operator.h"
     21 
     22 namespace toco {
     23 
     24 namespace tflite {
     25 
     26 // Custom operators have a generic byte buffer describing their options. This
     27 // class provides the boilerplate code for populating those options using
     28 // flexbuffers. Note that most of toco's operators will likely be supported
     29 // as builtin operators in TF Lite.
     30 //
     31 // Template argument T must derive from ::toco::Operator.
     32 template <typename T>
     33 class CustomOperator : public BaseOperator {
     34  public:
     35   using TocoOperator = T;
     36   using BaseOperator::BaseOperator;
     37 
     38   // Populate the given flexbuffer with options obtained from the tf.mini
     39   // operator.
     40   virtual void WriteOptions(const TocoOperator& op,
     41                             flexbuffers::Builder* fbb) const {}
     42 
     43   // Set options in the given tf.mini operator using values from the flexbuffer
     44   // map.
     45   virtual void ReadOptions(const flexbuffers::Map& m, TocoOperator* op) const {}
     46 
     47   Options Serialize(const Operator& op,
     48                     flatbuffers::FlatBufferBuilder* builder) const override {
     49     flexbuffers::Builder fbb;
     50     fbb.Map(
     51         [&]() { WriteOptions(static_cast<const TocoOperator&>(op), &fbb); });
     52     fbb.Finish();
     53     return Options::Custom(builder->CreateVector(fbb.GetBuffer()));
     54   }
     55 
     56   std::unique_ptr<Operator> Deserialize(
     57       const BuiltinOptions* builtin_options,
     58       const CustomOptions* custom_options) const override {
     59     auto op = absl::make_unique<TocoOperator>();
     60     if (custom_options) {
     61       auto flexbuffer_map =
     62           flexbuffers::GetRoot(custom_options->data(), custom_options->size())
     63               .AsMap();
     64       ReadOptions(flexbuffer_map, op.get());
     65     }
     66     return std::unique_ptr<Operator>(op.release());
     67   }
     68 };
     69 
     70 }  // namespace tflite
     71 
     72 }  // namespace toco
     73 
     74 #endif  // TENSORFLOW_CONTRIB_LITE_TOCO_TFLITE_CUSTOM_OPERATOR_H_
     75