/*
  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"
#include "proc/engine/buffer-metadata.hpp"
#include "lib/util.hpp"

using util::isSameObject;

namespace engine {
  
  
  namespace { // impl. details and definitions
    
    const uint DEFAULT_DESCRIPTOR = 0;
    
  }

  
  BufferProvider::BufferProvider (Literal implementationID)
    : meta_(new BufferMetadata (implementationID))
    { }
  
  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, meta_->key (storageSize));
  }
  
  
  BufferDescriptor
  BufferProvider::getDescriptorFor(size_t storageSize, TypeHandler specialTreatment)
  {
    return BufferDescriptor (*this, meta_->key (storageSize, specialTreatment));
  }
  
  
  BuffHandle
  BufferProvider::buildHandle (BufferDescriptor const& type, void* storage)
  {
    REQUIRE (was_created_by_this_provider (type));
    
    HashVal typeID (type.subClassification_);
    metadata::Key& typeKey = meta_->get (typeID);
    metadata::Entry& entry = meta_->markLocked(typeKey, newBlock);
    
    return BuffHandle (BufferDescriptor(*this, entry), newBlock);
  }
  
  
  bool
  was_created_by_this_provider (BufferDescriptor const& descr)  const
  {
    return isSameObject (this, descr.provider_);
  }
    
  
  
  
  
  /* === BufferDescriptor and BuffHandle === */
  
  bool
  BufferDescriptor::verifyValidity()  const
  {
    return provider_->verifyValidity(*this);
  }
  
  
  void
  BuffHandle::release()
  {
    UNIMPLEMENTED ("forward buffer release call to buffer provider");
  }
  


} // namespace engine