177 lines
3.3 KiB
C++
177 lines
3.3 KiB
C++
#ifndef _TCUMAYBE_HPP
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#define _TCUMAYBE_HPP
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/*-------------------------------------------------------------------------
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* drawElements Quality Program Tester Core
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* ----------------------------------------
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*
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* Copyright 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*//*!
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* \file
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* \brief Template for values that may not exist.
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*//*--------------------------------------------------------------------*/
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#include "tcuDefs.hpp"
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namespace tcu
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{
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// Empty struct used to initialize Maybe objects without providing the type explicitly.
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struct Nothing_T {
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explicit constexpr Nothing_T (int) {}
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};
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constexpr Nothing_T Nothing (0);
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// \note Type T is always aligned to same alignment as deUint64.
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// \note This type always uses at least sizeof(T*) + sizeof(deUint64) of memory.
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template<typename T>
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class Maybe
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{
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public:
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Maybe (void);
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Maybe (const Nothing_T&);
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~Maybe (void);
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Maybe (const T& val);
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Maybe<T>& operator= (const T& val);
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Maybe (const Maybe<T>& other);
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Maybe<T>& operator= (const Maybe<T>& other);
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const T& get (void) const;
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T& get (void);
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const T& operator* (void) const { return get(); }
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T& operator* (void) { return get(); }
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const T* operator-> (void) const;
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T* operator-> (void);
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operator bool (void) const { return !!m_ptr; }
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private:
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T* m_ptr;
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union
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{
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deUint8 m_data[sizeof(T)];
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deUint64 m_align;
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};
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} DE_WARN_UNUSED_TYPE;
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template<typename T>
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Maybe<T> nothing (void)
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{
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return Maybe<T>();
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}
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template<typename T>
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Maybe<T> just (const T& value)
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{
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return Maybe<T>(value);
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}
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template<typename T>
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Maybe<T>::Maybe (void)
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: m_ptr (nullptr)
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{
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}
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template<typename T>
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Maybe<T>::Maybe (const Nothing_T&)
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: m_ptr (nullptr)
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{
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}
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template<typename T>
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Maybe<T>::~Maybe (void)
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{
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if (m_ptr)
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m_ptr->~T();
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}
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template<typename T>
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Maybe<T>::Maybe (const T& val)
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: m_ptr (nullptr)
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{
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m_ptr = new(m_data)T(val);
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}
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template<typename T>
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Maybe<T>& Maybe<T>::operator= (const T& val)
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{
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if (m_ptr)
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m_ptr->~T();
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m_ptr = new(m_data)T(val);
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return *this;
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}
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template<typename T>
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Maybe<T>::Maybe (const Maybe<T>& other)
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: m_ptr (nullptr)
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{
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if (other.m_ptr)
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m_ptr = new(m_data)T(*other.m_ptr);
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}
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template<typename T>
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Maybe<T>& Maybe<T>::operator= (const Maybe<T>& other)
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{
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if (this == &other)
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return *this;
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if (m_ptr)
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m_ptr->~T();
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if (other.m_ptr)
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m_ptr = new(m_data)T(*other.m_ptr);
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else
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m_ptr = nullptr;
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return *this;
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}
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template<typename T>
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const T* Maybe<T>::operator-> (void) const
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{
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DE_ASSERT(m_ptr);
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return m_ptr;
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}
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template<typename T>
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T* Maybe<T>::operator-> (void)
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{
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DE_ASSERT(m_ptr);
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return m_ptr;
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}
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template<typename T>
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const T& Maybe<T>::get (void) const
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{
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DE_ASSERT(m_ptr);
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return *m_ptr;
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}
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template<typename T>
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T& Maybe<T>::get (void)
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{
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DE_ASSERT(m_ptr);
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return *m_ptr;
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}
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} // tcu
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#endif // _TCUMAYBE_HPP
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