[Skip] Optimize Skip for IRefStructCollection

Author: reegeek

src/StructLinq.Tests/RefSkipTests.cs

@@ -1,18 +1,19 @@
 using System.Linq;
 using StructLinq.Array;
 using StructLinq.Skip;
+using StructLinq.Where;
 using Xunit;
 
 namespace StructLinq.Tests
 {
     public class RefSkipTests : AbstractRefEnumerableTests<int,
-        RefSkipEnumerable<int, ArrayRefEnumerable<int>, ArrayRefStructEnumerator<int>>,
-        RefSkipEnumerator<int, ArrayRefStructEnumerator<int>>>
+        RefSkipEnumerable<int, RefWhereEnumerable<int, ArrayRefEnumerable<int>, ArrayRefStructEnumerator<int>, StructInFunction<int, bool>>, RefWhereEnumerator<int, ArrayRefStructEnumerator<int>, StructInFunction<int, bool>>> ,
+        RefSkipEnumerator<int, RefWhereEnumerator<int, ArrayRefStructEnumerator<int>, StructInFunction<int, bool>>>>
     {
-        protected override RefSkipEnumerable<int, ArrayRefEnumerable<int>, ArrayRefStructEnumerator<int>> Build(int size)
+        protected override RefSkipEnumerable<int, RefWhereEnumerable<int, ArrayRefEnumerable<int>, ArrayRefStructEnumerator<int>, StructInFunction<int, bool>>, RefWhereEnumerator<int, ArrayRefStructEnumerator<int>, StructInFunction<int, bool>>>  Build(int size)
         {
-            return StructEnumerable.Range(-1, size + 5).ToArray().ToRefStructEnumerable().Skip(5, x=> x);
-
+            var refSkipEnumerable = StructEnumerable.Range(-1, size + 5).ToArray().ToRefStructEnumerable().Where((in int x) => true, x=>x).Skip(5, x=> x);
+            return refSkipEnumerable;
         }
 
         [Theory]

src/StructLinq/Skip/StructCollection.Skip.cs

@@ -24,5 +24,24 @@ public static IStructCollection<T, TEnumerator> Skip<T, TEnumerator>(this IStruc
             newCollection.Slice(count, null);
             return newCollection;
         }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static TStructCollection Skip<T,TStructCollection, TEnumerator>(this TStructCollection collection, uint count, Func<TStructCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TStructCollection : struct, IRefStructCollection<T, TEnumerator>
+        {
+            var newCollection = collection;
+            newCollection.Slice(count, null);
+            return newCollection;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static IRefStructCollection<T, TEnumerator> Skip<T, TEnumerator>(this IRefStructCollection<T, TEnumerator> collection, uint count)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+        {
+            var newCollection = (IRefStructCollection<T, TEnumerator>)collection.Clone();
+            newCollection.Slice(count, null);
+            return newCollection;
+        }
     }
 }