DynamicAllocator.hpp

#pragma once
 
#include <string>
#include <functional>
#include <stdint.h>
#include <map>
#include <utility>
 
#include "../SmartPointers.hpp"
 
namespace Grindstone::Memory::Allocators {
    class DynamicAllocator {
    public:
        struct FreeHeader {
            size_t blockSize;
            FreeHeader* nextFreeBlock = nullptr;
        };
 
        struct AllocationHeader {
            size_t blockSize;
            char padding;
        };
 
        enum class SearchPolicy {
            FirstSearch = 0,
            BestSearch
        };
 
        ~DynamicAllocator();
 
        bool Initialize(size_t size);
        void Initialize(void* ownedMemory, size_t size);
 
        void* AllocateRaw(size_t size, size_t alignment, const char* debugName);
        bool Free(void* memPtr);
 
        bool IsEmpty() const;
 
        size_t GetTotalMemorySize() const;
        size_t GetPeakSize() const;
        size_t GetUsedSize() const;
        void* GetMemory() const;
 
        template<typename T, typename... Args>
        Grindstone::Memory::SmartPointers::SharedPtr<T> AllocateShared(Args&&... params) {
            T* ptr = static_cast<T*>(AllocateRaw(sizeof(T), alignof(T), typeid(T).name()));
            if (ptr != nullptr) {
                // Call the constructor on the newly allocated memory
                new (ptr) T(std::forward<Args>(params)...);
            }
 
            return SharedPtr<T>(ptr, deleterFn);
        }
 
        template<typename T, typename... Args>
        Grindstone::Memory::SmartPointers::UniquePtr<T> AllocateUnique(Args&&... params) {
            T* ptr = static_cast<T*>(AllocateRaw(sizeof(T), alignof(T), typeid(T).name()));
            if (ptr != nullptr) {
                // Call the constructor on the newly allocated memory
                new (ptr) T(std::forward<Args>(params)...);
            }
 
            return UniquePtr<T>(ptr, deleterFn);
        }
 
        template<typename T, typename... Args>
        T* AllocateRaw(Args&&... params) {
            T* ptr = static_cast<T*>(AllocateRaw(sizeof(T), alignof(T), typeid(T).name()));
            if (ptr != nullptr) {
                // Call the constructor on the newly allocated memory
                new (ptr) T(std::forward<Args>(params)...);
            }
 
            return ptr;
        }
 
        template<typename T>
        bool Free(void* memPtr) {
            if (memPtr != nullptr) {
                return false;
            }
 
            reinterpret_cast<T*>(memPtr)->~T();
            Free(memPtr);
 
            return true;
        }
 
    private:
        void FindAvailable(size_t size, size_t alignment, size_t& padding, FreeHeader*& previousFreeHeader, FreeHeader*& freeHeader) const;
        void FindAvailableFirst(size_t size, size_t alignment, size_t& padding, FreeHeader*& previousFreeHeader, FreeHeader*& freeHeader) const;
        void FindAvailableBest(size_t size, size_t alignment, size_t& padding, FreeHeader*& previousFreeHeader, FreeHeader*& freeHeader) const;
        void Coalesce(FreeHeader* previousNode, FreeHeader* freeNode);
        void InitializeImpl(void* ownedMemory, size_t size);
 
        void* startMemory = nullptr;
        void* endMemory = nullptr;
        FreeHeader* firstFreeHeader = nullptr;
 
        std::function<void(void*)> deleterFn;
        size_t totalMemorySize = 0;
        size_t usedSize = 0;
        size_t peakSize = 0;
        SearchPolicy searchPolicy = SearchPolicy::BestSearch;
        bool shouldClear = false;
        bool hasAllocatedOwnMemory = false;
 
#ifdef _DEBUG
        std::map<void*, const char*> nameMap;
#endif
    };
}