63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
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#pragma once
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#if !defined(MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED)
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#define MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED 1
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#include <array>
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#include <cstddef>
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#include <cstdint>
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#include <limits>
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#include <memory>
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#include <vector>
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#include "../debug/assert.hpp"
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namespace mijin
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{
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template<typename TObject, std::size_t OBJECTS_PER_PAGE = 1024>
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class ObjectPool
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{
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private:
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struct GapInfo
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{
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std::uint32_t objectCount;
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std::uint32_t nextGap;
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};
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static constexpr std::size_t ALIGN = std::max(alignof(TObject), alignof(GapInfo));
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struct alignas(ALIGN) ObjectData
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{
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std::array<std::byte, sizeof(TObject)> bytes;
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};
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struct Page
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{
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std::uint32_t freeOffset = 0;
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std::array<ObjectData, OBJECTS_PER_PAGE> data;
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};
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std::vector<std::unique_ptr<Page>> pages;
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public:
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[[nodiscard]] TObject* allocate(std::size_t count = 1) noexcept;
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void free(TObject* object, std::size_t count = 1) noexcept;
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};
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template<typename TObject, std::size_t OBJECTS_PER_PAGE>
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TObject* ObjectPool<TObject, OBJECTS_PER_PAGE>::allocate(std::size_t count) noexcept
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{
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MIJIN_ASSERT(count <= OBJECTS_PER_PAGE, "Cannot allocate more than OBJECTS_PER_PAGE elements at once!");
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// first try to find a free spot in the existing pages
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for (std::unique_ptr<Page>& page : pages)
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{
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std::uint32_t offset = page->freeOffset;
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while (offset < OBJECTS_PER_PAGE)
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{
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GapInfo& gapInfo = *std::bit_cast<GapInfo*>(&page->data[offset]);
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}
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}
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}
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} // namespace mijin
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#endif // !defined(MIJIN_MEMORY_OBJECT_POOL_HPP_INCLUDED)
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