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      1 /*
      2  * Copyright (C) 2016 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 V4L2_CAMERA_HAL_METADATA_DEFAULT_OPTION_DELEGATE_H_
     18 #define V4L2_CAMERA_HAL_METADATA_DEFAULT_OPTION_DELEGATE_H_
     19 
     20 #include <errno.h>
     21 
     22 #include <map>
     23 
     24 #include <hardware/camera3.h>
     25 
     26 namespace v4l2_camera_hal {
     27 
     28 // A constant that can be used to identify an overall default.
     29 static constexpr int OTHER_TEMPLATES = CAMERA3_TEMPLATE_COUNT;
     30 
     31 // DefaultingOptionDelegate provides an interface to get default options from.
     32 template <typename T>
     33 class DefaultOptionDelegate {
     34  public:
     35   // |defaults| maps template types to default values
     36   DefaultOptionDelegate(std::map<int, T> defaults)
     37       : defaults_(std::move(defaults)){};
     38   virtual ~DefaultOptionDelegate(){};
     39 
     40   // Get a default value for a template type. Returns false if no default
     41   // provided.
     42   virtual bool DefaultValueForTemplate(int template_type, T* default_value) {
     43     if (defaults_.count(template_type) > 0) {
     44       // Best option is template-specific.
     45       *default_value = defaults_[template_type];
     46       return true;
     47     } else if (defaults_.count(OTHER_TEMPLATES)) {
     48       // Fall back to a general default.
     49       *default_value = defaults_[OTHER_TEMPLATES];
     50       return true;
     51     }
     52 
     53     return false;
     54   };
     55 
     56  private:
     57   std::map<int, T> defaults_;
     58 };
     59 
     60 }  // namespace v4l2_camera_hal
     61 
     62 #endif  // V4L2_CAMERA_HAL_METADATA_DEFAULT_OPTION_DELEGATE_H_
     63