bump-allocator.hh

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/*
 
MIT License
 
Copyright (c) 2024 PCSX-Redux authors
 
Permission is hereby granted, free of charge, to any person obtaining a copy
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The above copyright notice and this permission notice shall be included in all
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SOFTWARE.
 
*/
 
#pragma once
 
#include <EASTL/utility.h>
#include <stdint.h>
 
#include "psyqo/fragments.hh"
#include "psyqo/kernel.hh"
#include "psyqo/primitive-concept.hh"
#include "psyqo/shared.hh"
 
namespace psyqo {
 
template <size_t N, Safe safety = Safe::Yes>
class BumpAllocator {
  public:
    template <Primitive P, typename... Args>
    Fragments::SimpleFragment<P> &allocateFragment(Args &&...args) {
        static constexpr size_t size = sizeof(Fragments::SimpleFragment<P>);
        if constexpr (safety == Safe::Yes) {
            psyqo::Kernel::assert(remaining() >= size, "BumpAllocator: Out of memory");
        }
        uint8_t *ptr = m_current;
        m_current += size;
        return *new (ptr) Fragments::SimpleFragment<P>(eastl::forward<Args>(args)...);
    }
    template <typename T, typename... Args>
    T &allocate(Args &&...args) {
        size_t size = sizeof(T);
        uint8_t *ptr = m_current;
        if constexpr (alignof(T) > 1) {
            static constexpr size_t a = alignof(T) - 1;
            auto alignedptr = reinterpret_cast<uint8_t *>((reinterpret_cast<uintptr_t>(ptr) + a) & ~a);
            size += alignedptr - ptr;
            ptr = alignedptr;
        }
        if constexpr (safety == Safe::Yes) {
            psyqo::Kernel::assert(remaining() >= size, "BumpAllocator: Out of memory");
        }
        m_current += size;
        return *new (ptr) T(eastl::forward<Args>(args)...);
    }
    void reset() { m_current = m_memory; }
    size_t remaining() const { return N - (m_current - m_memory); }
    size_t used() const { return m_current - m_memory; }
 
  private:
    uint8_t m_memory[N] __attribute__((aligned(4)));
    uint8_t *m_current = m_memory;
};
 
}  // namespace psyqo