text: /*
   * Copyright 2017 The Native Object Protocols Authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #ifndef LIBNOP_INCLUDE_NOP_BASE_ENUM_H_
  #define LIBNOP_INCLUDE_NOP_BASE_ENUM_H_
  
  #include <type_traits>
  
  #include <nop/base/encoding.h>
  
  namespace nop {
  
  // Enable if T is an enumeration type.
  template <typename T, typename ReturnType = void>
  using EnableIfEnum =
      typename std::enable_if<std::is_enum<T>::value, ReturnType>::type;
  
  //
  // enum encoding format matches the encoding format of the underlying integer
  // type.
  //
  
  template <typename T>
  struct Encoding<T, EnableIfEnum<T>> : EncodingIO<T> {
    static constexpr EncodingByte Prefix(const T& value) {
      return Encoding<IntegerType>::Prefix(static_cast<IntegerType>(value));
    }
  
    static constexpr std::size_t Size(const T& value) {
      return Encoding<IntegerType>::Size(static_cast<IntegerType>(value));
    }
  
    static constexpr bool Match(EncodingByte prefix) {
      return Encoding<IntegerType>::Match(prefix);
    }
  
    template <typename Writer>
    static constexpr Status<void> WritePayload(EncodingByte prefix,
                                               const T& value, Writer* writer) {
      return Encoding<IntegerType>::WritePayload(
          prefix, reinterpret_cast<const IntegerType&>(value), writer);
    }
  
    template <typename Reader>
    static constexpr Status<void> ReadPayload(EncodingByte prefix, T* value,
                                              Reader* reader) {
      return Encoding<IntegerType>::ReadPayload(
          prefix, reinterpret_cast<IntegerType*>(value), reader);
    }
  
   private:
    using IntegerType = typename std::underlying_type<T>::type;
  };
  
  }  // namespace nop
  
  #endif  // LIBNOP_INCLUDE_NOP_BASE_ENUM_H_
  