internal EntityReference ClaimReference()
{
int tempFreeIndex;
int newFreeIndex;
uint version;
do
{
tempFreeIndex = _nextFreeIndex;
// Check if we need to create a new EntityLocator or whether we can recycle an existing one.
if ((uint)tempFreeIndex >= _entityReferenceMap.count)
{
newFreeIndex = tempFreeIndex + 1;
version = 0;
}
else
{
ref EntityReferenceMapElement element = ref _entityReferenceMap[tempFreeIndex];
// The recycle entities form a linked list, using the egid.entityID to store the next element.
newFreeIndex = (int)element.egid.entityID;
version = element.version;
}
} while (tempFreeIndex != _nextFreeIndex.CompareExchange(newFreeIndex, tempFreeIndex));
#if DEBUG && !PROFILE_SVELTO
// This code should be safe since we own the tempFreeIndex, this allows us to later check that nothing went wrong.
if (tempFreeIndex < _entityReferenceMap.count)
{
_entityReferenceMap[tempFreeIndex] = new EntityReferenceMapElement(new EGID(0, 0), version);
}
#endif
return(new EntityReference((uint)tempFreeIndex + 1, version));
}
internal EntityReference CreateReferenceLocator(EGID egid)
{
// Check if we need to create a new EntityLocator or whether we can recycle an existing one.
EntityReference reference;
if (_nextReferenceIndex == _entityReferenceMap.count)
{
_entityReferenceMap.Add(new EntityReferenceMapElement(egid));
reference = new EntityReference(_nextReferenceIndex++);
}
//if _nextEntityId is not equivalent to the count of entity references added so far, it is
//pointing to the first deleted entity. A tombstone system recycles the entityID field to point
//it to the next deleted entity, similar to a linked list algorithm.
else
{
ref EntityReferenceMapElement element = ref _entityReferenceMap[_nextReferenceIndex];
reference = new EntityReference(_nextReferenceIndex, element.version);
// The recycle entities form a linked list, using the egid.entityID to store the next element.
_nextReferenceIndex = element.egid.entityID;
element.egid = egid;
}
