result.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2021 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
 
#ifndef ETL_RESULT_INCLUDED
#define ETL_RESULT_INCLUDED

 
#include "platform.h"
#include "optional.h"
#include "variant.h"
 
#if ETL_CPP11_NOT_SUPPORTED
  #if !defined(ETL_IN_UNIT_TEST)
    #error NOT SUPPORTED FOR C++03 OR BELOW
  #endif
#else
 
namespace etl
{
  //*****************************************************************************
  //*****************************************************************************
  template <typename TValue, typename TError>
  class result
  {
  public:
 
    typedef TValue value_type;
    typedef TError error_type;
 
    //*******************************************
    //*******************************************
    result() = delete;
 
    //*******************************************
    //*******************************************
    result(const result& other)
      : data(other.data)
    {
    }
 
  #if ETL_CPP11_SUPPORTED
    //*******************************************
    //*******************************************
    result(result&& other)
      : data(etl::move(other.data))
    {
    }
  #endif
 
    //*******************************************
    // Construct from a value
    //*******************************************
    result(const TValue& value)
      : data(value)
    {
    }
 
    //*******************************************
    // Move construct from a value
    //*******************************************
    result(TValue&& value)
      : data(etl::move(value))
    {
    }
 
    //*******************************************
    //*******************************************
    result(const TError& error)
      : data(error)
    {
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    result(TError&& error)
      : data(etl::move(error))
    {
    }
  #endif
 
    //*******************************************
    //*******************************************
    result& operator=(const result& other)
    {
      data = other.data;
      return *this;
    }
 
    //*******************************************
    //*******************************************
    result& operator=(result&& other)
    {
      data = etl::move(other.data);
      return *this;
    }
 
    //*******************************************
    //*******************************************
    result& operator=(const TValue& value)
    {
      data = value;
      return *this;
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    result& operator=(TValue&& value)
    {
      data = etl::move(value);
      return *this;
    }
  #endif
 
    //*******************************************
    //*******************************************
    result& operator=(const TError& error)
    {
      data = error;
      return *this;
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    result& operator=(TError&& error)
    {
      data = etl::move(error);
      return *this;
    }
  #endif
 
    //*******************************************
    //*******************************************
    bool has_value() const
    {
      return (data.index() == 0U);
    }
 
    //*******************************************
    //*******************************************
    bool is_value() const
    {
      return has_value();
    }
 
    //*******************************************
    //*******************************************
    bool is_error() const
    {
      return !has_value();
    }
 
    //*******************************************
    //*******************************************
    const TValue& value() const
    {
      return etl::get<TValue>(data);
    }
 
    //*******************************************
    //*******************************************
    TValue&& value()
    {
      return etl::move(etl::get<TValue>(data));
    }
 
    //*******************************************
    //*******************************************
    const TError& error() const
    {
      return etl::get<TError>(data);
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    TError&& error()
    {
      return etl::move(etl::get<TError>(data));
    }
  #endif
 
  private:
 
    etl::variant<TValue, TError> data;
  };
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename TError>
  class result<void, TError>
  {
  public:
 
    typedef void   value_type;
    typedef TError error_type;
 
    //*******************************************
    //*******************************************
    result() {}
 
    //*******************************************
    //*******************************************
    result(const result& other)
      : data(other.data)
    {
    }
 
    //*******************************************
    //*******************************************
    result(result&& other)
      : data(etl::move(other.data))
    {
    }
 
    //*******************************************
    //*******************************************
    result(const TError& error)
      : data(error)
    {
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    result(TError&& error)
      : data(etl::move(error))
    {
    }
  #endif
 
    //*******************************************
    //*******************************************
    result& operator=(const TError& error)
    {
      data = error;
      return *this;
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    result& operator=(TError&& error)
    {
      data = etl::move(error);
      return *this;
    }
  #endif
 
    //*******************************************
    //*******************************************
    bool has_value() const
    {
      return !data.has_value();
    }
 
    //*******************************************
    //*******************************************
    bool is_value() const
    {
      return has_value();
    }
 
    //*******************************************
    //*******************************************
    bool is_error() const
    {
      return !has_value();
    }
 
    //*******************************************
    //*******************************************
    const TError& error() const
    {
      return data.value();
    }
 
      //*******************************************
      //*******************************************
  #if ETL_CPP11_SUPPORTED
    TError&& error()
    {
      return etl::move(data.value());
    }
  #endif
 
  private:
 
    etl::optional<TError> data;
  };
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename TValue>
  class result<TValue, void>
  {
  public:
 
    //*******************************************
    //*******************************************
    result() {}
 
    //*******************************************
    //*******************************************
    result(const result& other)
      : data(other.data)
    {
    }
 
    //*******************************************
    //*******************************************
    result(result&& other)
      : data(etl::move(other.data))
    {
    }
 
    //*******************************************
    //*******************************************
    result(const TValue& value)
      : data(value)
    {
    }
 
    //*******************************************
    //*******************************************
    result(TValue&& value)
      : data(etl::move(value))
    {
    }
 
    //*******************************************
    //*******************************************
    result& operator=(const TValue& value)
    {
      data = value;
      return *this;
    }
 
    //*******************************************
    //*******************************************
    result& operator=(TValue&& value)
    {
      data = etl::move(value);
      return *this;
    }
 
    //*******************************************
    //*******************************************
    bool has_value() const
    {
      return data.has_value();
    }
 
    //*******************************************
    //*******************************************
    bool is_value() const
    {
      return has_value();
    }
 
    //*******************************************
    //*******************************************
    bool is_error() const
    {
      return !has_value();
    }
 
    //*******************************************
    //*******************************************
    const TValue& value() const
    {
      return data.value();
    }
 
    //*******************************************
    //*******************************************
    TValue&& value()
    {
      return etl::move(data.value());
    }
 
  private:
 
    etl::optional<TValue> data;
  };
} // namespace etl
#endif
 
#endif