heap_allocator.hpp

/**************************************************************************/
/* heap_allocator.hpp                                                     */
/**************************************************************************/
/*                         This file is part of:                          */
/*                                Knoodle                                 */
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/**************************************************************************/
/* Copyright (c) 2025 Knoodle contributors (vide AUTHORS.md)              */
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#pragma once
 
#include <stdlib.h>
#include <memory>
#include <new>
#include "core_api.hpp"
#include "kn_assert.hpp"
 
namespace kn {
class KN_CORE_API HeapAllocator {
 public:
  HeapAllocator(const HeapAllocator&) = delete;
  HeapAllocator& operator=(const HeapAllocator&) = delete;
 
  HeapAllocator() = default;
  ~HeapAllocator() = default;
 
  [[nodiscard]] inline size_t get_allocated_size() const { return _allocated_size; }
  [[nodiscard]] inline size_t get_deallocated_size() const { return _deallocated_size; }
  [[nodiscard]] inline size_t get_total_size() const { return _allocated_size - _deallocated_size; }
 
  static HeapAllocator* get_instance();
 
  template <typename T>
  T* allocate(size_t count = 1, size_t alignment = 1) {
    size_t desired_size = count * sizeof(T);
    _allocated_size += desired_size;
 
    T* obj = nullptr;
 
    void* ptr = nullptr;
#if defined(_MSC_VER)
    ptr = _aligned_malloc(desired_size, alignment);
#else
    posix_memalign(&ptr, alignment, desired_size);
#endif
 
    if (ensure(ptr)) {
      obj = reinterpret_cast<T*>(ptr);
      for (uint32_t i = 0; i < count; ++i) {
        new (reinterpret_cast<T*>(ptr) + i) T;
      }
      return obj;
    }
 
    return nullptr;
  }
 
  template <typename T>
  void deallocate(T* ptr, size_t count = 1) {
    if (ensure(ptr)) {
      size_t desired_size = count * sizeof(T);
      _deallocated_size += desired_size;
      for (uint32_t i = 0; i < count; ++i) {
        ptr[i].~T();
      }
    }
  }
 
 private:
  static std::unique_ptr<HeapAllocator> instance;
 
  size_t _allocated_size = 0;
  size_t _deallocated_size = 0;
};
}  // namespace kn