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Diffstat (limited to 'src/atomic.h')
-rw-r--r-- | src/atomic.h | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/src/atomic.h b/src/atomic.h new file mode 100644 index 0000000..95a5e9d --- /dev/null +++ b/src/atomic.h @@ -0,0 +1,182 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/*************************************************************************** + * atomic.h + * + * Wed Mar 23 09:15:05 CET 2016 + * Copyright 2016 Christian Glöckner + * cgloeckner@freenet.de + ****************************************************************************/ + +/* + * This file is part of DrumGizmo. + * + * DrumGizmo is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * DrumGizmo is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with DrumGizmo; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ +#pragma once + +#include <type_traits> +#include <atomic> + +#include <mutex> +#include "mutex.h" + +template <typename T, typename = void> +class Atomic; + +// use std::atomic if possible +template <typename T> +class Atomic<T, typename std::enable_if<std::is_pod<T>::value>::type> + : public std::atomic<T> +{ +public: + // inherit methods + using std::atomic<T>::atomic; + using std::atomic<T>::operator=; +}; + +// else work around it using a mutex +template <typename T> +class Atomic<T, typename std::enable_if<!std::is_pod<T>::value>::type> +{ +public: + using self_type = + Atomic<T, typename std::enable_if<!std::is_pod<T>::value>::type>; + + Atomic() + : data{} + , mutex{} + { + } + + Atomic(T data) + : data{std::move(data)} + , mutex{} + { + } + + Atomic(self_type const & other) + : data{} + , mutex{} + { + std::lock_guard<std::mutex> lock{other.mutex}; + data = other.data; + } + + Atomic(self_type&& other) + : data{} + , mutex{} + { + std::lock_guard<std::mutex> lock{other.mutex}; + std::swap(data, other.data); + } + + T operator=(T data) + { + std::lock_guard<std::mutex> lock{mutex}; + this->data = std::move(data); + return this->data; + } + + operator T() const + { + return load(); + } + + bool is_lock_free() const + { + return false; + } + + void store(T data) + { + std::lock_guard<std::mutex> lock{mutex}; + this->data = std::move(data); + } + + T load() const { + std::lock_guard<std::mutex> lock{mutex}; + return data; + } + + T exchange(T data){ + std::lock_guard<std::mutex> lock{mutex}; + std::swap(data, this->data); + return data; + } + + bool operator==(const T& other) const + { + std::lock_guard<std::mutex> lock{mutex}; + return other == data; + } + + bool operator!=(const T& other) const + { + std::lock_guard<std::mutex> lock{mutex}; + return !(other == data); + } + + bool operator==(const Atomic<T>& other) const + { + std::lock_guard<std::mutex> lock{mutex}; + return other.load() == data; + } + + bool operator!=(const Atomic<T>& other) const + { + std::lock_guard<std::mutex> lock{mutex}; + return !(other.load() == data); + } + +private: + T data; + mutable std::mutex mutex; +}; + +//! Getter utility class. +template <typename T> class SettingRef +{ +public: + SettingRef(Atomic<T>& value) + : value(value) + { + // string isn't lock free either + assert((std::is_same<T, std::string>::value || value.is_lock_free())); + } + + bool hasChanged() + { + T tmp = cache; + cache.exchange(value); + + if(firstAccess) + { + firstAccess = false; + return true; + } + + return cache != tmp; + } + + T getValue() const + { + return cache; + } + +private: + bool firstAccess{true}; + Atomic<T>& value; + Atomic<T> cache; +}; |