/*
  BufferProvider  -  Abstraction for Buffer management during playback/render

  Copyright (C)         Lumiera.org
    2008,               Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of
  the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

* *****************************************************/


#include "proc/engine/buffer-provider.hpp"

namespace engine {
  
  
  namespace { // impl. details and definitions
    
    const uint DEFAULT_DESCRIPTOR = 0;
    
    typedef uint64_t LocalKey;
    typedef size_t HashVal;
    
    const LocalKey UNSPECIFIC = 0;
    
    struct TypeHandler
      {
        typedef void (*Ctor) (void*);
        typedef void (*Dtor) (void*);
        
        Ctor createAttached;
        Dtor destroyAttached;
        
        TypeHandler()
          : createAttached (0)
          , destroyAttached (0)
          { }
        
        template<class X>
        TypeHandler()
          : createAttached (0)    /////////TODO: how to attach the ctor function??? mabye better use a class with virtual functions?
          , destroyAttached (0)
          { }
      };
    
    const TypeHandler RAW_BUFFER;
    
    
    class Metadata
      {
      public:
        static HashVal
        key ( size_t storageSize
            , TypeHandler instanceFunc =RAW_BUFFER
            , LocalKey specifics =UNSPECIFIC)
        {
          UNIMPLEMENTED ("combine the distinguishing properties into a single hash");
        }
      };
  }


  BufferProvider::~BufferProvider() { }
  
  
  /** @internal verify the given descriptor.
   *  @return true if it corresponds to a buffer
   *          currently locked and usable by client code
   */
  bool
  BufferProvider::verifyValidity (BufferDescriptor const&)
  {
    UNIMPLEMENTED ("BufferProvider basic and default implementation");
  }
  
  
  BufferDescriptor
  BufferProvider::getDescriptorFor (size_t storageSize)
  {
    return BufferDescriptor (*this, Metadata::key (storageSize));
  }
      
      
  
  
  /* === BufferDescriptor and BuffHandle === */
  
  bool
  BufferDescriptor::verifyValidity()  const
  {
    return provider_->verifyValidity(*this);
  }
  
  
  void
  BuffHandle::release()
  {
    UNIMPLEMENTED ("forward buffer release call to buffer provider");
  }
  


} // namespace engine