two_step_value.h

Go to the documentation of this file.

#pragma once
#include <utility>
 
namespace hgps {
 
template <typename TYPE> struct TwoStepValue {
    TwoStepValue() = default;
 
    TwoStepValue(TYPE value) : value_{value}, old_value_{} {}
 
    TYPE value() const { return value_; }
 
    TYPE old_value() const { return old_value_; }
 
    void set_both_values(TYPE new_value) {
        value_ = new_value;
        old_value_ = new_value;
    }
 
    void set_value(TYPE new_value) { old_value_ = std::exchange(value_, new_value); }
 
    TYPE operator()() const { return value_; }
 
    void operator=(TYPE new_value) { set_value(new_value); }
 
    TwoStepValue<TYPE> clone() {
        auto clone = TwoStepValue<TYPE>{old_value()};
        clone = value();
        return clone;
    }
 
  private:
    TYPE value_{};
    TYPE old_value_{};
};
} // namespace hgps