etl/pool_base.h

///\file

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

Embedded Template Library.

Copyright(c) 2014 jwellbelove

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#ifndef __ETL_IN_IPOOL_H__
#error This header is a private element of etl::pool & etl::ipool
#endif

#ifndef __ETL_POOL_BASE__
#define __ETL_POOL_BASE__

#include <stddef.h>

#include "exception.h"

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

namespace etl
{
  //***************************************************************************
  /// The base class for pool exceptions.
  ///\ingroup pool
  //***************************************************************************
  class pool_exception : public exception
  {
  public:

    pool_exception(const char* what)
      : exception(what)
    {}
  };

  //***************************************************************************
  /// The exception thrown when the pool has no more free items.
  ///\ingroup pool
  //***************************************************************************
  class pool_no_allocation : public pool_exception
  {
  public:

    pool_no_allocation()
      : pool_exception("pool: no allocation")
    {}
  };

  //***************************************************************************
  /// The exception thrown when an object is released which does not belong to the pool.
  ///\ingroup pool
  //***************************************************************************
  class pool_object_not_in_pool : public pool_exception
  {
  public:

    pool_object_not_in_pool()
      : pool_exception("pool: not in pool")
    {}
  };
  
  //*************************************************************************
  /// The base class for all templated pool types.
  ///\ingroup pool
  //*************************************************************************
  class pool_base
  {
  public:

    //*************************************************************************
    /// Returns the number of free items in the pool.
    //*************************************************************************
    size_t available() const
    {
      return MAX_SIZE - items_allocated;
    }

    //*************************************************************************
    /// Checks to see if there are no free items in the pool.
    /// \return <b>true</b> if there are none free (or 'empty')
    //*************************************************************************
    bool empty() const
    {
      return items_allocated == MAX_SIZE;
    }

  protected:

    //*************************************************************************
    /// Constructor
    //*************************************************************************
    pool_base(size_t max_size)
      : next_free(0),
        items_allocated(0),
        MAX_SIZE(max_size)       
    {
    }

    size_t       next_free;       ///< The position of the next free item in the pool.
    size_t       items_allocated; ///< The number of items allocated.
    const size_t MAX_SIZE;        ///< The maximum number of objects that can be allocated.
  };
}
#endif