[Last] improve last for IRefStructCollection

Author: reegeek

src/StructLinq/Last/RefStructCollection.Last.cs

@@ -0,0 +1,135 @@
+// ReSharper disable once CheckNamespace
+
+using System;
+using System.Runtime.CompilerServices;
+
+// ReSharper disable once CheckNamespace
+namespace StructLinq
+{
+    public static partial class StructEnumerable
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Last<T, TCollection, TEnumerator>(this TCollection collection, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+        {
+            T last = default;
+            if (TryLast(collection, ref last, x=>x))
+                return last;
+            throw new Exception("No Elements");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Last<T, TEnumerator>(this IRefStructCollection<T, TEnumerator> collection)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+        {
+            T last = default;
+            if (TryLast(collection, ref last))
+                return last;
+            throw new Exception("No Elements");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Last<T, TCollection, TEnumerator>(this TCollection collection, Func<T, bool> predicate, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+        {
+            T last = default;
+            if (TryLast(collection, predicate, ref last, x=>x))
+                return last;
+            throw new Exception("No Elements");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Last<T, TEnumerator>(this IRefStructCollection<T, TEnumerator> collection, Func<T, bool> predicate)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+        {
+            T last = default;
+            if (TryLast(collection, predicate, ref last))
+                return last;
+            throw new Exception("No Elements");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Last<T, TCollection, TEnumerator, TFunc>(this TCollection collection, ref TFunc predicate, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+            where TFunc : struct, IInFunction<T, bool>
+        {
+            T last = default;
+            if (TryLast(collection, ref predicate, ref last, x=>x))
+                return last;
+            throw new Exception("No Elements");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryLast<T, TCollection, TEnumerator>(this TCollection collection, ref T last, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+        {
+            if (collection.Count == 0)
+                return false;
+            last = collection.Get(collection.Count - 1);
+            return true;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryLast<T, TEnumerator>(this IRefStructCollection<T, TEnumerator> collection, ref T last)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+        {
+            if (collection.Count == 0)
+                return false;
+            last = collection.Get(collection.Count - 1);
+            return true;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryLast<T, TCollection, TEnumerator>(this TCollection collection, Func<T, bool> predicate, ref T last, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+        {
+            if (collection.Count == 0)
+                return false;
+            for (int i = collection.Count - 1; i >= 0; i--)
+            {
+                last = collection.Get(i);
+                if (predicate(last))
+                    return true;
+            }
+            return false;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryLast<T, TEnumerator>(this IRefStructCollection<T, TEnumerator> collection, Func<T, bool> predicate, ref T last)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+        {
+            if (collection.Count == 0)
+                return false;
+            for (int i = collection.Count - 1; i >= 0; i--)
+            {
+                last = collection.Get(i);
+                if (predicate(last))
+                    return true;
+            }
+            return false;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryLast<T, TCollection, TEnumerator, TFunc>(this TCollection collection, ref TFunc predicate, ref T last, Func<TCollection, IRefStructCollection<T, TEnumerator>> _)
+            where TEnumerator : struct, IRefStructEnumerator<T>
+            where TCollection : IRefStructCollection<T, TEnumerator>
+            where TFunc : struct, IInFunction<T, bool>
+        {
+            if (collection.Count == 0)
+                return false;
+            for (int i = collection.Count - 1; i >= 0; i--)
+            {
+                last = collection.Get(i);
+                if (predicate.Eval(in last))
+                    return true;
+            }
+            return false;
+        }
+
+    }
+}