private static List <MergeRecord> RemoveOldValues(List <T> remainings, List <T> others, out List <int> existingPositions)
{
var result = new List <MergeRecord>();
var i = 0;
var dictionary = others.SafeToDictionary(item => item, item => i++);
var othersSet = others.ToHashSet();
existingPositions = new List <int>();
MergeRecord currentMergeRecord = null;
var index = 0;
var array = remainings.ToArray();
remainings.Clear();
foreach (var item in array)
{
if (!othersSet.Contains(item))
{
if (currentMergeRecord == null)
{
currentMergeRecord = new MergeRecord();
currentMergeRecord.Update(item, false, index++);
result.Add(currentMergeRecord);
}
else
{
currentMergeRecord.Update(item);
index++;
}
}
else
{
existingPositions.Add(dictionary[item]);
remainings.Add(item);
index++;
if (currentMergeRecord != null)
{
index -= currentMergeRecord.Items.Count;
currentMergeRecord = null;
}
}
}
return(result);
}
protected override IEnumerable <MergeRecord> UpdateOverride(IEnumerable <T> others)
{
if (others == null)
{
Clear();
return(Enumerable.Empty <MergeRecord>());
}
var myEnumerator = GetEnumerator();
var othersArray = others as T[] ?? others.ToArray();
var otherEnumerator = othersArray.GetEnumerator();
var thisHas = myEnumerator.MoveNext();
var otherHas = otherEnumerator.MoveNext();
if (!thisHas && otherHas)
{
ViewArray = (T[])othersArray.Clone();
return(new List <MergeRecord> {
new MergeRecord {
StartIndex = 0, IsAdd = true, Items = ViewArray
}
});
}
if (thisHas && !otherHas)
{
var oldItems = ViewArray;
ViewArray = new T[0];
return(new List <MergeRecord> {
new MergeRecord {
StartIndex = 0, IsAdd = false, Items = oldItems
}
});
}
var newArray = new T[othersArray.Count()];
var index = 0;
MergeRecord currentRecord = null;
var result = new List <MergeRecord>();
while (thisHas && otherHas)
{
var myItem = myEnumerator.Current;
var otherItem = (T)otherEnumerator.Current;
var compareResult = Comparison(myItem, otherItem);
if (compareResult < 0)
{
if (currentRecord == null || currentRecord.IsAdd)
{
var isAdd = currentRecord != null;
currentRecord = new MergeRecord();
result.Add(currentRecord);
currentRecord.Update(myItem, false, index + (isAdd ? 1 : 0));
}
else
{
currentRecord.Update(myItem);
}
thisHas = myEnumerator.MoveNext();
}
else if (compareResult > 0)
{
if (currentRecord == null || !currentRecord.IsAdd)
{
currentRecord = new MergeRecord();
result.Add(currentRecord);
currentRecord.Update(otherItem, true, index);
}
else
{
currentRecord.Update(otherItem);
}
newArray[index++] = otherItem;
otherHas = otherEnumerator.MoveNext();
}
else
{
if (!Equals(myItem, otherItem))
{
if (currentRecord == null || !currentRecord.IsReplace)
{
currentRecord = new MergeRecord();
result.Add(currentRecord);
currentRecord.UpdateReplace(myItem, otherItem, index);
}
else
{
currentRecord.UpdateReplace(myItem, otherItem);
}
newArray[index++] = otherItem;
}
else
{
currentRecord = null;
newArray[index] = otherItem;
index++;
}
thisHas = myEnumerator.MoveNext();
otherHas = otherEnumerator.MoveNext();
}
}
// Se acabó el primero pero le queda al segundo
if (otherHas)
{
if (currentRecord == null || currentRecord.IsReplace || !currentRecord.IsAdd)
{
currentRecord = new MergeRecord {
IsAdd = true, StartIndex = index
};
result.Add(currentRecord);
}
while (otherHas)
{
var current = (T)otherEnumerator.Current;
newArray[index++] = current;
currentRecord.Update(current);
otherHas = otherEnumerator.MoveNext();
}
}
// Se acabó el segundo pero le queda al primero
if (thisHas)
{
if (currentRecord == null || currentRecord.IsReplace || currentRecord.IsAdd)
{
currentRecord = new MergeRecord {
IsAdd = false, StartIndex = index
};
result.Add(currentRecord);
}
while (thisHas)
{
currentRecord.Update(myEnumerator.Current);
thisHas = myEnumerator.MoveNext();
}
}
ViewArray = newArray;
return(result);
}