/// <summary>Removes an index from the map and returns whether things still seem to be consistent.</summary>
private protected static bool RemoveIndex(AllowNullDictionary <T, CircularList <int> > map, T item, int index)
{
if (!map.TryGetValue(item, out CircularList <int> indices) || !RemoveIndex(indices, index))
{
return(false);
}
if (indices.Count == 0)
{
map.Remove(item);
}
return(true);
}
private protected static bool AdjustIndex(AllowNullDictionary <T, CircularList <int> > map, T item, int startIndex, int diff, HashSet <T> adjustedValues)
{
if (adjustedValues.Contains(item))
{
return(true);
}
adjustedValues.Add(item);
if (!map.TryGetValue(item, out var indices))
{
return(false);
}
AdjustIndex(indices, startIndex, diff);
return(true);
}
private void BuildIndexMap(bool rebuild = true)
{
if (itemToIndex.Count > 0)
{
itemToIndex = new AllowNullDictionary <T, CircularList <int> >();
}
int length = Count;
for (int i = 0; i < length; i++)
{
T item = base.GetItem(i);
AddIndex(itemToIndex, item, i);
}
if (rebuild)
{
OnMapRebuilt();
}
}
/// <summary>Adds an index to the map and returns whether things still seem to be consistent.</summary>
private protected static bool AddIndex(AllowNullDictionary <T, CircularList <int> > map, T item, int index)
{
if (!map.TryGetValue(item, out CircularList <int> indices))
{
indices = new CircularList <int>(1);
map[item] = indices;
}
if (indices.Count == 0 || index > indices[indices.Count - 1])
{
indices.AddLast(index);
return(true);
}
var pos = indices.BinarySearch(index);
if (pos >= 0)
{
return(false);
}
indices.Insert(~pos, index);
return(true);
}
private void AssertConsistency <T>(FastLookupCollection <T> coll)
{
var itemToIndex = new AllowNullDictionary <T, CircularList <int> >();
for (int i = 0; i < coll.Count; i++)
{
T item = coll[i];
if (!itemToIndex.TryGetValue(item, out CircularList <int> indices))
{
indices = new CircularList <int>();
itemToIndex[item] = indices;
}
indices.Add(i);
}
var actualItemToIndex = (AllowNullDictionary <T, CircularList <int> >)Reflector.GetField(coll, "itemToIndex");
AssertItemsEqual(Sorted(itemToIndex), Sorted(actualItemToIndex));
IEnumerable Sorted(AllowNullDictionary <T, CircularList <int> > dict)
=> new AllowNullDictionary <T, CircularList <int> >(dict.OrderBy(item => item.Key));
}
private protected static bool ContainsIndex(AllowNullDictionary <T, CircularList <int> > map, T item, int index) => map.TryGetValue(item, out var indices) && indices.Contains(index);
private protected static int GetFirstIndex(AllowNullDictionary <T, CircularList <int> > map, T item) => map.TryGetValue(item, out CircularList <int> indices) ? indices[0] : -1;
