public static ArraySegment <T> ToImmutableArray <T> (this IEnumerable <T> enumerable, int maximumCount)
{
int count = maximumCount;
var buffer = ImmutableArrayPool <T> .Allocate(maximumCount);
using (var e = enumerable.GetEnumerator()) {
for (var i = 0; i < count; i++)
{
if (!e.MoveNext())
{
count = i;
break;
}
buffer.Array[i + buffer.Offset] = e.Current;
}
if (e.MoveNext())
{
throw new ArgumentException("Enumerable was longer", "maximumCount");
}
}
if (buffer.Array == null)
{
return(ImmutableArrayPool <T> .Empty);
}
else
{
return(new ArraySegment <T>(buffer.Array, buffer.Offset, count));
}
}
public static ArraySegment <T> ToImmutableArray <T> (this IEnumerable <T> enumerable)
{
var collection = enumerable as ICollection <T>;
#if TARGETTING_FX_4_5
var readOnlyCollection = enumerable as IReadOnlyCollection <T>;
#endif
var array = enumerable as T[];
if (collection != null)
{
var count = collection.Count;
var buffer = ImmutableArrayPool <T> .Allocate(count);
collection.CopyTo(buffer.Array, buffer.Offset);
return(buffer);
#if TARGETTING_FX_4_5
}
else if (readOnlyCollection != null)
{
return(ToImmutableArray(enumerable, readOnlyCollection.Count));
#endif
}
else if (array != null)
{
return(new ArraySegment <T>(array));
}
else
{
// Slow path =[
array = enumerable.ToArray();
return(new ArraySegment <T>(array));
}
}
