ipool.h

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/******************************************************************************
The MIT License(MIT)

Embedded Template Library.

Copyright(c) 2014 jwellbelove

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of this software and associated documentation files(the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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******************************************************************************/

#ifndef __ETL_IPOOL__
#define __ETL_IPOOL__
#define __ETL_IN_IPOOL_H__

#include "pool_base.h"
#include "nullptr.h"

#ifndef ETL_THROW_EXCEPTIONS
#include "error_handler.h"
#endif

namespace etl
{
  //*************************************************************************
  //*************************************************************************
  template <typename T>
  class ipool : public pool_base
  {
  public:

    //*************************************************************************
    //*************************************************************************
    T* allocate()
    {
      if (next_free != MAX_SIZE)
      {
        T* result = &p_buffer[next_free];
        in_use_flags.set(next_free);
        next_free = in_use_flags.find_first(false);
        ++items_allocated;
        return result;
      }
      else
      {
#ifdef ETL_THROW_EXCEPTIONS
        throw pool_no_allocation();
#else
        error_handler::error(pool_no_allocation());
#endif
        return nullptr;
      }
    }
    
    //*************************************************************************
    //*************************************************************************
    void release(const T& object)
    {
      release(&object);
    }

    //*************************************************************************
    //*************************************************************************
    void release(const T* const p_object)
    {
      // Does it belong to me?
      if (is_in_pool(p_object))
      {
        typename std::iterator_traits<T*>::difference_type distance = p_object - p_buffer;

        // Mark the object as available.
        next_free = static_cast<size_t>(distance);
        in_use_flags.reset(next_free);
        --items_allocated;
      }
      else
      {
#ifdef ETL_THROW_EXCEPTIONS
        throw pool_object_not_in_pool();
#else
        error_handler::error(pool_object_not_in_pool());
#endif
      }
    }

    //*************************************************************************
    //*************************************************************************
    bool is_in_pool(const T& object) const
    {
      return is_in_pool(&object);
    }

    //*************************************************************************
    //*************************************************************************
    bool is_in_pool(const T* const p_object) const
    {
      // Does this object belong to this pool?
      typename std::iterator_traits<T*>::difference_type distance = p_object - p_buffer;

      // Within the range of the buffer?
      return ((distance >= 0) && (distance < static_cast<typename std::iterator_traits<T*>::difference_type>(MAX_SIZE)));
    }

  protected:

    //*************************************************************************
    //*************************************************************************
    ipool(T* p_buffer, ibitset& in_use_flags, size_t size)
      : pool_base(size),
        p_buffer(nullptr),
        in_use_flags(in_use_flags)
    {
    }

    T* p_buffer;
    ibitset& in_use_flags;
  };
}
#endif