optional.h

// =====================================================================================================================
// Copyright 2024 Medusa Slockbower
// 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 OPTIONAL_H
#define OPTIONAL_H
 
namespace open_cpp_utils
{
    template<typename T>
    class optional
    {
    public:
        using value_type = T;
 
        optional() : data_(), valid_(false) { }
        optional(const value_type& data) : data_(data), valid_(true) { }
        optional(value_type&& data) : data_(data), valid_(true) { }
        optional(const optional& other) = default;
        optional(optional&& other) = default;
 
        optional& operator=(const optional& other) = default;
        optional& operator=(optional&& other) = default;
 
        optional& operator=(const value_type& data) { data_ = data; valid_ = true; return *this; }
        optional& operator=(value_type&& data) { data_ = data; valid_ = true; return *this; }
 
        value_type& operator+=(const value_type& data) { assert(valid_); data_ += data; return data_; }
        value_type& operator-=(const value_type& data) { assert(valid_); data_ += data; return data_; }
        value_type& operator*=(const value_type& data) { assert(valid_); data_ += data; return data_; }
        value_type& operator/=(const value_type& data) { assert(valid_); data_ += data; return data_; }
        value_type& operator%=(const value_type& data) { assert(valid_); data_ += data; return data_; }
 
        value_type& operator<<=(const value_type& data) { assert(valid_); data_ <<= data; return data_; }
        value_type& operator>>=(const value_type& data) { assert(valid_); data_ >>= data; return data_; }
        value_type& operator|=(const value_type& data)  { assert(valid_); data_ |= data;  return data_; }
        value_type& operator&=(const value_type& data)  { assert(valid_); data_ &= data;  return data_; }
        value_type& operator^=(const value_type& data)  { assert(valid_); data_ ^= data;  return data_; }
 
        [[nodiscard]] bool operator()() const { return valid_; }
 
        operator       value_type&()       { assert(valid_); return data_; }
        operator const value_type&() const { assert(valid_); return data_; }
 
              value_type* operator->()       { assert(valid_); return &data_; }
        const value_type* operator->() const { assert(valid_); return &data_; }
 
              value_type& operator*()        { assert(valid_); return data_; }
        const value_type& operator*() const  { assert(valid_); return data_; }
 
        void reset() { valid_ = false; }
 
    private:
        value_type data_;
        bool valid_;
    };
}
 
#endif //OPTIONAL_H