| #ifndef _TCUMAYBE_HPP |
| #define _TCUMAYBE_HPP |
| /*------------------------------------------------------------------------- |
| * drawElements Quality Program Tester Core |
| * ---------------------------------------- |
| * |
| * Copyright 2015 The Android Open Source Project |
| * |
| * 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. |
| * |
| *//*! |
| * \file |
| * \brief Template for values that may not exist. |
| *//*--------------------------------------------------------------------*/ |
| |
| #include "tcuDefs.hpp" |
| |
| namespace tcu |
| { |
| |
| // Empty struct used to initialize Maybe objects without providing the type explicitly. |
| struct Nothing_T |
| { |
| explicit constexpr Nothing_T(int) |
| { |
| } |
| }; |
| constexpr Nothing_T Nothing(0); |
| |
| // \note Type T is always aligned to same alignment as uint64_t. |
| // \note This type always uses at least sizeof(T*) + sizeof(uint64_t) of memory. |
| template <typename T> |
| class Maybe |
| { |
| public: |
| Maybe(void); |
| Maybe(const Nothing_T &); |
| ~Maybe(void); |
| |
| Maybe(const T &val); |
| Maybe<T> &operator=(const T &val); |
| |
| Maybe(const Maybe<T> &other); |
| Maybe<T> &operator=(const Maybe<T> &other); |
| |
| const T &get(void) const; |
| T &get(void); |
| const T &operator*(void) const |
| { |
| return get(); |
| } |
| T &operator*(void) |
| { |
| return get(); |
| } |
| |
| const T *operator->(void) const; |
| T *operator->(void); |
| operator bool(void) const |
| { |
| return !!m_ptr; |
| } |
| |
| private: |
| T *m_ptr; |
| |
| union |
| { |
| uint8_t m_data[sizeof(T)]; |
| uint64_t m_align; |
| }; |
| } DE_WARN_UNUSED_TYPE; |
| |
| template <typename T> |
| Maybe<T> nothing(void) |
| { |
| return Maybe<T>(); |
| } |
| |
| template <typename T> |
| Maybe<T> just(const T &value) |
| { |
| return Maybe<T>(value); |
| } |
| |
| template <typename T> |
| Maybe<T>::Maybe(void) : m_ptr(nullptr) |
| { |
| } |
| |
| template <typename T> |
| Maybe<T>::Maybe(const Nothing_T &) : m_ptr(nullptr) |
| { |
| } |
| |
| template <typename T> |
| Maybe<T>::~Maybe(void) |
| { |
| if (m_ptr) |
| m_ptr->~T(); |
| } |
| |
| template <typename T> |
| Maybe<T>::Maybe(const T &val) : m_ptr(nullptr) |
| { |
| m_ptr = new (m_data) T(val); |
| } |
| |
| template <typename T> |
| Maybe<T> &Maybe<T>::operator=(const T &val) |
| { |
| if (m_ptr) |
| m_ptr->~T(); |
| |
| m_ptr = new (m_data) T(val); |
| |
| return *this; |
| } |
| |
| template <typename T> |
| Maybe<T>::Maybe(const Maybe<T> &other) : m_ptr(nullptr) |
| { |
| if (other.m_ptr) |
| m_ptr = new (m_data) T(*other.m_ptr); |
| } |
| |
| template <typename T> |
| Maybe<T> &Maybe<T>::operator=(const Maybe<T> &other) |
| { |
| if (this == &other) |
| return *this; |
| |
| if (m_ptr) |
| m_ptr->~T(); |
| |
| if (other.m_ptr) |
| m_ptr = new (m_data) T(*other.m_ptr); |
| else |
| m_ptr = nullptr; |
| |
| return *this; |
| } |
| |
| template <typename T> |
| const T *Maybe<T>::operator->(void) const |
| { |
| DE_ASSERT(m_ptr); |
| return m_ptr; |
| } |
| |
| template <typename T> |
| T *Maybe<T>::operator->(void) |
| { |
| DE_ASSERT(m_ptr); |
| return m_ptr; |
| } |
| |
| template <typename T> |
| const T &Maybe<T>::get(void) const |
| { |
| DE_ASSERT(m_ptr); |
| return *m_ptr; |
| } |
| |
| template <typename T> |
| T &Maybe<T>::get(void) |
| { |
| DE_ASSERT(m_ptr); |
| return *m_ptr; |
| } |
| |
| } // namespace tcu |
| |
| #endif // _TCUMAYBE_HPP |