allocator.h

//----------------------------------------------------------------------------//
//                                                                            //
// ozz-animation is hosted at http://github.com/guillaumeblanc/ozz-animation  //
// and distributed under the MIT License (MIT).                               //
//                                                                            //
// Copyright (c) Guillaume Blanc                                              //
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//----------------------------------------------------------------------------//
 
#ifndef OZZ_OZZ_BASE_MEMORY_ALLOCATOR_H_
#define OZZ_OZZ_BASE_MEMORY_ALLOCATOR_H_
 
#include <cstddef>
#include <new>
#include <utility>
 
#include "ozz/base/platform.h"
 
namespace ozz {
namespace memory {
 
// Forwards declare Allocator class.
class Allocator;
 
// Defines the default allocator accessor.
OZZ_BASE_DLL Allocator* default_allocator();
 
// Set the default allocator, used for all dynamic allocation inside ozz.
// Returns current memory allocator, such that in can be restored if needed.
OZZ_BASE_DLL Allocator* SetDefaulAllocator(Allocator* _allocator);
 
// Defines an abstract allocator class.
// Implements helper methods to allocate/deallocate POD typed objects instead of
// raw memory.
// Implements New and Delete function to allocate C++ objects, as a replacement
// of new and delete operators.
class OZZ_BASE_DLL Allocator {
 public:
  // Default virtual destructor.
  virtual ~Allocator() {}
 
  // Next functions are the pure virtual functions that must be implemented by
  // allocator concrete classes.
 
  // Allocates _size bytes on the specified _alignment boundaries.
  // Allocate function conforms with standard malloc function specifications.
  virtual void* Allocate(size_t _size, size_t _alignment) = 0;
 
  // Frees a block that was allocated with Allocate or Reallocate.
  // Argument _block can be nullptr.
  // Deallocate function conforms with standard free function specifications.
  virtual void Deallocate(void* _block) = 0;
};
}  // namespace memory
 
// ozz replacement for c++ operator new with, used to allocate with an
// ozz::memory::Allocator. Delete must be used to deallocate such object.
// It can be used for constructor with no argument:
// Type* object = New<Type>();
// or any number of argument:
// Type* object = New<Type>(1,2,3,4);
template <typename _Ty, typename... _Args>
_Ty* New(_Args&&... _args) {
  void* alloc =
      memory::default_allocator()->Allocate(sizeof(_Ty), alignof(_Ty));
  return new (alloc) _Ty(std::forward<_Args>(_args)...);
}
 
template <typename _Ty>
void Delete(_Ty* _object) {
  if (_object) {
    // Prevents from false "unreferenced parameter" warning when _Ty has no
    // explicit destructor.
    (void)_object;
    _object->~_Ty();
    memory::default_allocator()->Deallocate(_object);
  }
}
 
}  // namespace ozz
#endif  // OZZ_OZZ_BASE_MEMORY_ALLOCATOR_H_