// Filename: deletedBufferChain.I
// Created by:  drose (20Jul07)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001 - 2004, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://etc.cmu.edu/panda3d/docs/license/ .
//
// To contact the maintainers of this program write to
// panda3d-general@lists.sourceforge.net .
//
////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////
//     Function: DeletedBufferChain::validate
//       Access: Public
//  Description: Returns true if the pointer is valid, false if it has
//               been deleted or if it was never a valid pointer.
//
//               This is only meaningful in debug mode, where
//               USE_DELETEDCHAINFLAG is defined.  If not, this
//               trivially returns true.
////////////////////////////////////////////////////////////////////
INLINE bool DeletedBufferChain::
validate(void *ptr) {
  TAU_PROFILE("bool DeletedBufferChain::validate(void *)", " ", TAU_USER);
  if (ptr == (void *)NULL) {
    return false;
  }

#ifdef USE_DELETEDCHAINFLAG
  const ObjectNode *obj = buffer_to_node(ptr);
  return AtomicAdjust::get(obj->_flag) == DCF_alive;
#else
  return true;
#endif  // USE_DELETEDCHAINFLAG
}

////////////////////////////////////////////////////////////////////
//     Function: DeletedBufferChain::get_buffer_size
//       Access: Public
//  Description: Returns the size of the buffer that is actually
//               returned at each request.
////////////////////////////////////////////////////////////////////
INLINE size_t DeletedBufferChain::
get_buffer_size() const {
  return _buffer_size;
}

////////////////////////////////////////////////////////////////////
//     Function: DeletedBufferChain::node_to_buffer
//       Access: Private, Static
//  Description: Casts an ObjectNode* to a void* buffer.
////////////////////////////////////////////////////////////////////
INLINE void *DeletedBufferChain::
node_to_buffer(DeletedBufferChain::ObjectNode *node) {
#ifdef USE_DELETEDCHAINFLAG
  // In development mode, we increment the pointer so that the
  // returned data does not overlap our _flags member.
  return (void *)(((PN_int32 *)node) + 1);
#else
  return (void *)node;
#endif  // NDEBUG
}

////////////////////////////////////////////////////////////////////
//     Function: DeletedBufferChain::buffer_to_node
//       Access: Private, Static
//  Description: Casts a void* buffer to an ObjectNode* .
////////////////////////////////////////////////////////////////////
INLINE DeletedBufferChain::ObjectNode *DeletedBufferChain::
buffer_to_node(void *ptr) {
#ifdef USE_DELETEDCHAINFLAG
  // In development mode, we decrement the pointer to undo the
  // increment we did above.
  return (ObjectNode *)(((PN_int32 *)ptr) - 1);
#else
  return (ObjectNode *)ptr;
#endif  // NDEBUG
}