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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_RANGED_CONVERTER_H_
     18 #define V4L2_CAMERA_HAL_METADATA_RANGED_CONVERTER_H_
     19 
     20 #include <memory>
     21 
     22 #include "../common.h"
     23 #include "converter_interface.h"
     24 
     25 namespace v4l2_camera_hal {
     26 
     27 // An RangedConverter fits values converted by a wrapped converter
     28 // to a stepped range (when going from metadata -> v4l2. The other
     29 // direction remains unchanged).
     30 template <typename TMetadata, typename TV4L2>
     31 class RangedConverter : public ConverterInterface<TMetadata, TV4L2> {
     32  public:
     33   RangedConverter(
     34       std::shared_ptr<ConverterInterface<TMetadata, TV4L2>> wrapped_converter,
     35       TV4L2 min,
     36       TV4L2 max,
     37       TV4L2 step);
     38 
     39   virtual int MetadataToV4L2(TMetadata value, TV4L2* conversion) override;
     40   virtual int V4L2ToMetadata(TV4L2 value, TMetadata* conversion) override;
     41 
     42  private:
     43   std::shared_ptr<ConverterInterface<TMetadata, TV4L2>> wrapped_converter_;
     44   const TV4L2 min_;
     45   const TV4L2 max_;
     46   const TV4L2 step_;
     47 
     48   DISALLOW_COPY_AND_ASSIGN(RangedConverter);
     49 };
     50 
     51 // -----------------------------------------------------------------------------
     52 
     53 template <typename TMetadata, typename TV4L2>
     54 RangedConverter<TMetadata, TV4L2>::RangedConverter(
     55     std::shared_ptr<ConverterInterface<TMetadata, TV4L2>> wrapped_converter,
     56     TV4L2 min,
     57     TV4L2 max,
     58     TV4L2 step)
     59     : wrapped_converter_(std::move(wrapped_converter)),
     60       min_(min),
     61       max_(max),
     62       step_(step) {
     63   HAL_LOG_ENTER();
     64 }
     65 
     66 template <typename TMetadata, typename TV4L2>
     67 int RangedConverter<TMetadata, TV4L2>::MetadataToV4L2(TMetadata value,
     68                                                       TV4L2* conversion) {
     69   HAL_LOG_ENTER();
     70 
     71   TV4L2 raw_conversion = 0;
     72   int res = wrapped_converter_->MetadataToV4L2(value, &raw_conversion);
     73   if (res) {
     74     HAL_LOGE("Failed to perform underlying conversion.");
     75     return res;
     76   }
     77 
     78   // Round down to step (steps start at min_).
     79   raw_conversion -= (raw_conversion - min_) % step_;
     80 
     81   // Clamp to range.
     82   if (raw_conversion < min_) {
     83     raw_conversion = min_;
     84   } else if (raw_conversion > max_) {
     85     raw_conversion = max_;
     86   }
     87 
     88   *conversion = raw_conversion;
     89   return 0;
     90 }
     91 
     92 template <typename TMetadata, typename TV4L2>
     93 int RangedConverter<TMetadata, TV4L2>::V4L2ToMetadata(TV4L2 value,
     94                                                       TMetadata* conversion) {
     95   HAL_LOG_ENTER();
     96 
     97   return wrapped_converter_->V4L2ToMetadata(value, conversion);
     98 }
     99 
    100 }  // namespace v4l2_camera_hal
    101 
    102 #endif  // V4L2_CAMERA_HAL_METADATA_RANGED_CONVERTER_H_
    103