stateless_allocators.h

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#ifndef INCLUDED_STATELESS_ALLOCATORS
#define INCLUDED_STATELESS_ALLOCATORS

#include "lib/sysdep/rtl.h"
#include "lib/sysdep/vm.h"

#include <memory>

// NB: STL allocators are parameterized on the object type and indicate
// the number of elements to [de]allocate. however, these adapters are
// only used for allocating storage and receive the number of bytes.

struct Allocator_Heap
{
    void* allocate(size_t size)
    {
        return malloc(size);
    }

    void deallocate(void* p, size_t UNUSED(size))
    {
        return free(p);
    }
};

template<size_t alignment = allocationAlignment>
struct Allocator_Aligned
{
    void* allocate(size_t size)
    {
        return rtl_AllocateAligned(size, alignment);
    }

    void deallocate(void* p, size_t UNUSED(size))
    {
        return rtl_FreeAligned(p);
    }
};

template<vm::PageType pageType = vm::kDefault, int prot = PROT_READ|PROT_WRITE>
struct Allocator_VM
{
    void* allocate(size_t size)
    {
        return vm::Allocate(size, pageType, prot);
    }

    void deallocate(void* p, size_t size)
    {
        vm::Free(p, size);
    }
};

template<size_t commitSize = g_LargePageSize, vm::PageType pageType = vm::kDefault, int prot = PROT_READ|PROT_WRITE>
struct Allocator_AddressSpace
{
    void* allocate(size_t size)
    {
        return vm::ReserveAddressSpace(size, commitSize, pageType, prot);
    }

    void deallocate(void* p, size_t size)
    {
        vm::ReleaseAddressSpace(p, size);
    }
};

#endif  // INCLUDED_STATELESS_ALLOCATORS