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181 рядки
4.5 KiB
181 рядки
4.5 KiB
#pragma once
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#include <gp/algorithm/tmp_manip.hpp>
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#include <type_traits>
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#include <new>
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#include "gp_config.hpp"
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#include "gp/exception.hpp"
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#include "gp/memory.hpp"
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#include "gp/function.hpp"
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namespace gp{
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template<typename ...T>
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class fixed_variant{
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std::size_t index = std::numeric_limits<std::size_t>::max();
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char buffer[max_size<T...>()];
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gp::function<void(void*)> dtor = [](void*){};
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static_assert(all_of_fixed_size<T...>::value, "not fixed");
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public:
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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constexpr fixed_variant(U& value)
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: index{r_index_of<U, T...>::value}
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{
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new(buffer) U(value);
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dtor = gp::function([](void* thing){((U*)thing)->~U();});
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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constexpr fixed_variant(U&& value)
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: index{r_index_of<U, T...>::value}
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{
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new(buffer) U(std::move(value));
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dtor = gp::function([](void* thing){((U*)thing)->~U();});
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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void operator=(U& value)
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor((void*)buffer);
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}
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index = r_index_of<U, T...>::value;
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new(buffer) U(value);
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dtor = gp::function([](void* thing){((U*)thing)->~U();});
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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void operator=(U&& value)
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor((void*)buffer);
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}
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index = r_index_of<U, T...>::value;
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new(buffer) U(std::move(value));
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dtor = gp::function([](void* thing){((U*)thing)->~U();});
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}
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~fixed_variant()
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor((void*)buffer);
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}
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}
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template<typename U>
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constexpr U& value()
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{
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if constexpr (gp_config::has_exceptions)
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{
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if(r_index_of<U, T...>::value != index)
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{
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throw bad_variant_access<U>{};
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}
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}
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return *reinterpret_cast<U*>(buffer);
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}
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template<typename U>
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constexpr U& is_a()
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{
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if(r_index_of<U, T...>::value == index)
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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};
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template<typename allocator_t = gp_config::memory_module::default_allocator, typename ...T>
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class variant{
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std::size_t index = std::numeric_limits<std::size_t>::max();
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void* ptr;
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gp::function<void(void*)> dtor = [](void*){};
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allocator_t allocator;
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public:
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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constexpr variant(U& value)
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: index{r_index_of<U, T...>::value}
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{
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ptr = (void*)new(allocator.allocate(sizeof(U))) U(value);
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dtor = gp::function([](void* thing){((U*)thing)->~U();}); // TODO:replae with delete(p,t)
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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constexpr variant(U&& value)
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: index{r_index_of<U, T...>::value}
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{
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ptr = (void*)new(allocator.allocate(sizeof(U))) U(std::move(value));
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dtor = gp::function([](void* thing){((U*)thing)->~U();}); // TODO:replae with delete(p,t)
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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void operator=(U& value)
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor(ptr);
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allocator.deallocate(ptr);
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}
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index = r_index_of<U, T...>::value;
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ptr = (void*)new(allocator.allocate(sizeof(U))) U(value);
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dtor = gp::function([](void* thing){((U*)thing)->~U();}); // TODO:replae with delete(p,t)
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}
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template<typename U, typename std::enable_if<list_contains_class<U,T...>::value,int>::type>
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void operator=(U&& value)
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor(ptr);
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allocator.deallocate(ptr);
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}
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index = r_index_of<U, T...>::value;
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ptr = (void*)new(allocator.allocate(sizeof(U))) U(std::move(value));
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dtor = gp::function([](void* thing){((U*)thing)->~U();}); // TODO: replace with delete(p, t)
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}
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~variant()
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{
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if(index != std::numeric_limits<std::size_t>::max())
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{
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dtor(ptr);
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allocator.deallocate(ptr);
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}
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}
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template<typename U>
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constexpr U& value()
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{
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if constexpr (gp_config::has_exceptions)
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{
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if(r_index_of<U, T...>::value != index)
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{
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throw bad_variant_access<U>{};
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}
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}
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return *reinterpret_cast<U*>(ptr);
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}
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template<typename U>
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constexpr U& is_a()
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{
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if(r_index_of<U, T...>::value == index)
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{
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return true;
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}
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else
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{
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return false;
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}
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}
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};
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}
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