text: 
  //
  // This source file is part of appleseed.
  // Visit https://appleseedhq.net/ for additional information and resources.
  //
  // This software is released under the MIT license.
  //
  // Copyright (c) 2010-2013 Francois Beaune, Jupiter Jazz Limited
  // Copyright (c) 2014-2018 Francois Beaune, The appleseedhq Organization
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #pragma once
  
  // appleseed.foundation headers.
  #include "foundation/core/exceptions/exception.h"
  #include "foundation/platform/compiler.h"
  #include "foundation/utility/memory.h"
  
  // Standard headers.
  #include <cassert>
  #include <cstddef>
  #include <cstdint>
  
  namespace foundation
  {
  
  //
  // An arena is a temporary heap providing extremely cheap memory allocation.
  //
  
  class Arena
  {
    public:
      Arena();
  
      void clear();
  
      void* allocate(const size_t size);
  
      template <typename T> T* allocate();
      template <typename T> T* allocate_noinit();
  
      const std::uint8_t* get_storage() const;
  
    private:
      enum { ArenaSize = 384 * 1024 };    // bytes
  
      APPLESEED_SIMD4_ALIGN std::uint8_t  m_storage[ArenaSize];
      const std::uint8_t*                 m_end;
      std::uint8_t*                       m_current;
  };
  
  
  //
  // Arena class implementation.
  //
  
  inline Arena::Arena()
    : m_end(m_storage + ArenaSize)
    , m_current(m_storage)
  {
  }
  
  inline void Arena::clear()
  {
      m_current = m_storage;
  }
  
  inline void* Arena::allocate(const size_t size)
  {
      if (m_current + size > m_end)
          throw Exception("out of arena memory");
  
      void* ptr = m_current;
      m_current += align(size, 16);
  
      assert(is_aligned(ptr, 16));
  
      return ptr;
  }
  
  template <typename T>
  inline T* Arena::allocate()
  {
      T* ptr = static_cast<T*>(allocate(sizeof(T)));
  
      new (ptr) T();
  
      return ptr;
  }
  
  template <typename T>
  inline T* Arena::allocate_noinit()
  {
      return static_cast<T*>(allocate(sizeof(T)));
  }
  
  inline const std::uint8_t* Arena::get_storage() const
  {
      return m_storage;
  }
  
  }   // namespace foundation
  