mirror of https://github.com/bsnes-emu/bsnes.git
74 lines
2.8 KiB
C++
74 lines
2.8 KiB
C++
#ifndef NALL_FUNCTION_HPP
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#define NALL_FUNCTION_HPP
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#include <nall/traits.hpp>
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namespace nall {
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template<typename T> struct function;
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template<typename R, typename... P> struct function<auto (P...) -> R> {
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//value = true if auto L::operator()(P...) -> R exists
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template<typename L> struct is_compatible {
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template<typename T> static auto exists(T*) -> const typename is_same<R, decltype(declval<T>().operator()(declval<P>()...))>::type;
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template<typename T> static auto exists(...) -> const false_type;
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static constexpr bool value = decltype(exists<L>(0))::value;
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};
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function() = default;
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function(const function& source) { operator=(source); }
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function(void* function) { if(function) callback = new global((auto (*)(P...) -> R)function); }
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function(auto (*function)(P...) -> R) { callback = new global(function); }
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template<typename C> function(auto (C::*function)(P...) -> R, C* object) { callback = new member<C>(function, object); }
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template<typename C> function(auto (C::*function)(P...) const -> R, C* object) { callback = new member<C>((auto (C::*)(P...) -> R)function, object); }
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template<typename L, typename = enable_if<is_compatible<L>>> function(const L& object) { callback = new lambda<L>(object); }
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~function() { if(callback) delete callback; }
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explicit operator bool() const { return callback; }
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auto operator()(P... p) const -> R { return (*callback)(forward<P>(p)...); }
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auto reset() -> void { if(callback) { delete callback; callback = nullptr; } }
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auto operator=(const function& source) -> function& {
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if(this != &source) {
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if(callback) { delete callback; callback = nullptr; }
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if(source.callback) callback = source.callback->copy();
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}
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return *this;
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}
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private:
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struct container {
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virtual auto operator()(P... p) const -> R = 0;
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virtual auto copy() const -> container* = 0;
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virtual ~container() = default;
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};
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container* callback = nullptr;
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struct global : container {
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auto (*function)(P...) -> R;
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auto operator()(P... p) const -> R { return function(forward<P>(p)...); }
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auto copy() const -> container* { return new global(function); }
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global(auto (*function)(P...) -> R) : function(function) {}
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};
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template<typename C> struct member : container {
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auto (C::*function)(P...) -> R;
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C* object;
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auto operator()(P... p) const -> R { return (object->*function)(forward<P>(p)...); }
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auto copy() const -> container* { return new member(function, object); }
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member(auto (C::*function)(P...) -> R, C* object) : function(function), object(object) {}
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};
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template<typename L> struct lambda : container {
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mutable L object;
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auto operator()(P... p) const -> R { return object(forward<P>(p)...); }
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auto copy() const -> container* { return new lambda(object); }
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lambda(const L& object) : object(object) {}
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};
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};
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}
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#endif
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