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/*
* libfud
* Copyright 2024 Dominick Allen
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FUD_ALLOCATOR_HPP
#define FUD_ALLOCATOR_HPP
#include "fud_result.hpp"
#include "fud_status.hpp"
#include <cstddef>
#include <limits>
namespace fud {
/** \brief The default allocation function for globalFudAllocator. */
extern std::byte* fudAlloc(size_t size);
/** \brief The default deallocation function for globalFudAllocator. */
extern void fudFree(std::byte* ptr);
class alignas(std::max_align_t) Allocator {
public:
virtual ~Allocator() = default;
virtual Result<std::byte*, FudStatus> allocate(size_t bytes, size_t alignment = alignof(std::max_align_t)) = 0;
virtual void deallocate(std::byte* pointer, size_t bytes) = 0;
virtual bool isEqual(const Allocator& rhs) const = 0;
};
constexpr bool operator==(const Allocator& lhs, const Allocator& rhs)
{
return &lhs == &rhs;
}
class FudAllocator : public Allocator {
public:
virtual ~FudAllocator() override = default;
virtual Result<std::byte*, FudStatus> allocate(size_t bytes, size_t alignment = alignof(std::max_align_t)) override;
virtual void deallocate(std::byte* pointer, size_t bytes) override;
virtual bool isEqual(const Allocator& rhs) const override;
};
extern FudAllocator globalFudAllocator;
class NullAllocator : public Allocator {
public:
virtual ~NullAllocator() override = default;
virtual Result<std::byte*, FudStatus> allocate(size_t bytes, size_t alignment = alignof(std::max_align_t)) override;
virtual void deallocate(std::byte* pointer, size_t bytes) override;
virtual bool isEqual(const Allocator& rhs) const override;
};
extern NullAllocator globalNullAllocator;
template <size_t Size>
class SimpleStackAllocator final : public Allocator {
private:
std::byte m_memory[Size]{};
size_t m_allocated{0};
public:
virtual ~SimpleStackAllocator() override final = default;
virtual Result<std::byte*, FudStatus> allocate(size_t bytes, size_t alignment = alignof(std::max_align_t)) override final {
using RetType = Result<std::byte*, FudStatus>;
static_cast<void>(alignment);
if (bytes > Size - m_allocated) {
return RetType::error(FudStatus::AllocFailure);
}
auto* data = m_memory + m_allocated;
m_allocated += bytes;
return RetType::okay(data);
}
virtual void deallocate(std::byte* pointer, size_t bytes) override final
{
if (pointer + bytes != m_memory + m_allocated) {
m_allocated = Size;
return;
}
m_allocated -= bytes;
}
virtual bool isEqual(const Allocator& rhs) const override final {
return &rhs == this;
}
};
} // namespace fud
#endif
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