/// <summary>
/// Returns a new Query representing the original Query but without any duplicates.
/// The order of the elements in the returned query is undefined.
///
/// For example
/// (A, B, C, A, B, C, D).Query().Distinct()
/// Could result in
/// (B, A, C, D)
/// </summary>
public static Query <T> Distinct <T>(this Query <T> query)
{
T[] array;
int count;
query.Deconstruct(out array, out count);
HashSet <T> set = LightPool <HashSet <T> > .Spawn();
for (int i = 0; i < count; i++)
{
set.Add(array[i]);
}
Array.Clear(array, 0, array.Length);
count = 0;
foreach (var item in set)
{
array[count++] = item;
}
set.Clear();
LightPool <HashSet <T> > .Recycle(set);
return(new Query <T>(array, count));
}
/// <summary>
/// Constructs a new Query from the given IEnumerable
/// </summary>
public static Query <T> Query <T>(this IEnumerable <T> enumerable)
{
List <T> list = LightPool <List <T> > .Spawn();
try
{
list.AddRange(enumerable);
return(new Query <T>(list));
}
finally
{
list.Clear();
LightPool <List <T> > .Recycle(list);
}
}
/// <summary>
/// Constructs a new Query from the given IEnumerator
/// </summary>
public static Query <T> Query <T>(this IEnumerator <T> enumerator)
{
List <T> list = LightPool <List <T> > .Spawn();
try
{
while (enumerator.MoveNext())
{
list.Add(enumerator.Current);
}
return(new Query <T>(list));
}
finally
{
list.Clear();
LightPool <List <T> > .Recycle(list);
}
}
/// <summary>
/// Counts the number of distinct elements in the Query.
/// </summary>
public static int CountUnique <T>(this Query <T> query)
{
var slice = query.Deconstruct();
var set = LightPool <HashSet <T> > .Spawn();
try
{
for (int i = 0; i < slice.Count; i++)
{
set.Add(slice[i]);
}
return(set.Count);
}
finally
{
slice.Dispose();
set.Clear();
LightPool <HashSet <T> > .Recycle(set);
}
}
