refactoring to support c# 7.3

src/Builtin/BaseProcesses.cs

@@ -35,8 +35,9 @@ namespace DCFApixels.DragonECS
 #if DEBUG && !DISABLE_DEBUG
                 for (int i = 0; i < targets.Length && targets.Length <= _markers.Length; i++)
                 {
-                    using (_markers[i].Auto())
+                    _markers[i].Begin();
-                        targets[i].PreInit(pipeline);
+                    targets[i].PreInit(pipeline);
+                    _markers[i].End();
                 }
 #else
             foreach (var item in targets) item.PreInit(pipeline);
@@ -64,8 +65,9 @@ namespace DCFApixels.DragonECS
 #if DEBUG && !DISABLE_DEBUG
                 for (int i = 0; i < targets.Length && targets.Length <= _markers.Length; i++)
                 {
-                    using (_markers[i].Auto())
+                    _markers[i].Begin();
-                        targets[i].Init(pipeline);
+                    targets[i].Init(pipeline);
+                    _markers[i].End();
                 }
 #else
             foreach (var item in targets) item.Init(pipeline);
@@ -93,9 +95,9 @@ namespace DCFApixels.DragonECS
 #if DEBUG && !DISABLE_DEBUG
                 for (int i = 0; i < targets.Length && targets.Length <= _markers.Length; i++)
                 {
-                    using (_markers[i].Auto())
+                    _markers[i].Begin();
-                        targets[i].Run(pipeline);
+                    targets[i].Run(pipeline);
-
+                    _markers[i].End();
                 }
 #else
             foreach (var item in targets) item.Run(pipeline);
@@ -123,8 +125,9 @@ namespace DCFApixels.DragonECS
 #if DEBUG && !DISABLE_DEBUG
                 for (int i = 0; i < targets.Length && targets.Length <= _markers.Length; i++)
                 {
-                    using (_markers[i].Auto())
+                    _markers[i].Begin();
-                        targets[i].Destroy(pipeline);
+                    targets[i].Destroy(pipeline);
+                    _markers[i].End();
                 }
 #else
             foreach (var item in targets) item.Destroy(pipeline);

src/EcsGroup.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -468,7 +469,7 @@ namespace DCFApixels.DragonECS
         #endregion
 
         #region Object
-        public override string ToString() => string.Join(", ", _dense.AsSpan(1, _count).ToArray());
+        public override string ToString() => string.Join(", ", _dense.Cast<string>(), 0, _count);
         public override bool Equals(object obj) => obj is EcsGroup group && Equals(group);
         public bool Equals(EcsReadonlyGroup other) => Equals(other.GetGroupInternal());
         public bool Equals(EcsGroup other)

src/EcsSubject.cs

@@ -45,8 +45,8 @@ namespace DCFApixels.DragonECS
             {
                 _world = world;
                 _subjects = new List<CombinedSubject>();
-                _inc = new HashSet<int>(8);
+                _inc = new HashSet<int>();
-                _exc = new HashSet<int>(4);
+                _exc = new HashSet<int>();
             }
             internal static TSubject Build<TSubject>(EcsWorld world) where TSubject : EcsSubject
             {

src/Executors/EcsWhereExecutor.cs

@@ -33,15 +33,14 @@
         public EcsReadonlyGroup ExecuteFor(EcsReadonlyGroup sourceGroup)
         {
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            using (_executeWhere.Auto())
+            _executeWhere.Begin();
+            if (sourceGroup.IsNull) throw new System.ArgumentNullException();//TODO составить текст исключения. 
 #endif
-            {
+            _subject.GetIteratorFor(sourceGroup).CopyTo(_filteredGroup);
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-                if (sourceGroup.IsNull) throw new System.ArgumentNullException();//TODO составить текст исключения. 
+            _executeWhere.End();
 #endif
-                _subject.GetIteratorFor(sourceGroup).CopyTo(_filteredGroup);
+            return _filteredGroup.Readonly;
-                return _filteredGroup.Readonly;
-            }
         }
 #endregion
     }

src/Utils/ReadOnlySpanDummy.cs

@@ -0,0 +1,187 @@
+#if ENABLE_DUMMY_SPAN
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using EditorBrowsableAttribute = System.ComponentModel.EditorBrowsableAttribute;
+using EditorBrowsableState = System.ComponentModel.EditorBrowsableState;
+
+namespace DCFApixels.DragonECS
+{
+    internal static class ThrowHelper
+    {
+        public static void ThrowIndexOutOfRangeException() => throw new IndexOutOfRangeException();
+        public static void ThrowArgumentOutOfRangeException() => throw new ArgumentOutOfRangeException();
+        public static void ThrowInvalidOperationException() => throw new InvalidOperationException();
+    }
+    [DebuggerDisplay("{ToString(),raw}")]
+    public readonly ref struct ReadOnlySpan<T>
+    {
+        public static ReadOnlySpan<T> Empty => new ReadOnlySpan<T>(null);
+
+        internal readonly T[] _array;
+        private readonly int _start;
+        private readonly int _length;
+
+        #region Properties
+        public int Length => _length;
+        public bool IsEmpty => _length == 0;
+        public ref readonly T this[int index]
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get
+            {
+                if ((uint)index >= (uint)_length || (uint)index < 0)
+                    ThrowHelper.ThrowIndexOutOfRangeException();
+                return ref _array[index + _start];
+            }
+        }
+        #endregion
+
+        #region Constructors
+        public ReadOnlySpan(T[] array)
+        {
+            _array = array ?? Array.Empty<T>();
+            _start = 0;
+            _length = array.Length;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public ReadOnlySpan(T[] array, int start, int length)
+        {
+            if (array == null)
+            {
+                if (start != 0 || length != 0)
+                    ThrowHelper.ThrowArgumentOutOfRangeException();
+                _array = Array.Empty<T>();
+                _start = 0;
+                _length = 0;
+                return;
+            }
+
+            if ((uint)start > (uint)array.Length || (uint)length > (uint)(array.Length - start))
+                ThrowHelper.ThrowArgumentOutOfRangeException();
+
+            _array = array;
+            _start = start;
+            _length = length;
+        }
+        #endregion
+
+        #region Object
+        [Obsolete("Equals() on ReadOnlySpan will always throw an exception. Use the equality operator instead.")]
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override bool Equals(object obj) => throw new NotSupportedException();
+        [Obsolete("GetHashCode() on ReadOnlySpan will always throw an exception.")]
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override int GetHashCode() => throw new NotSupportedException();
+        public override string ToString()
+        {
+            //if (typeof(T) == typeof(char))
+            //    return new string(new ReadOnlySpan<char>(ref Unsafe.As<T, char>(ref _reference), _length));
+            return $"System.ReadOnlySpan<{typeof(T).Name}>[{_length}]";
+        }
+        #endregion
+
+        #region operators
+        public static bool operator !=(ReadOnlySpan<T> left, ReadOnlySpan<T> right) => !(left == right);
+
+        public static implicit operator ReadOnlySpan<T>(T[] array) => new ReadOnlySpan<T>(array);
+
+        public static implicit operator ReadOnlySpan<T>(ArraySegment<T> segment) => new ReadOnlySpan<T>(segment.Array, segment.Offset, segment.Count);
+        public static bool operator ==(ReadOnlySpan<T> left, ReadOnlySpan<T> right) => left._length == right._length && left._array == right._array;
+        #endregion
+
+        #region Enumerator
+        public Enumerator GetEnumerator() => new Enumerator(this);
+        public ref struct Enumerator
+        {
+            private readonly ReadOnlySpan<T> _span;
+            private int _index;
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            internal Enumerator(ReadOnlySpan<T> span)
+            {
+                _span = span;
+                _index = span._start - 1;
+            }
+            public ref readonly T Current
+            {
+                [MethodImpl(MethodImplOptions.AggressiveInlining)]
+                get => ref _span[_index];
+            }
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public bool MoveNext()
+            {
+                int index = _index + 1;
+                if (index < _span.Length)
+                {
+                    _index = index;
+                    return true;
+                }
+                return false;
+            }
+        }
+        #endregion
+
+        #region Other
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public ref readonly T GetPinnableReference()
+        {
+            if (_length != 0) ThrowHelper.ThrowInvalidOperationException();
+            return ref _array[0];
+        }
+
+        //[MethodImpl(MethodImplOptions.AggressiveInlining)]
+        //public void CopyTo(Span<T> destination)
+        //{
+        //    if ((uint)_length <= (uint)destination.Length)
+        //    {
+        //        Buffer.Memmove(ref destination._reference, ref _reference, (uint)_length);
+        //    }
+        //    else
+        //    {
+        //        ThrowHelper.ThrowArgumentException_DestinationTooShort();
+        //    }
+        //}
+
+        //public bool TryCopyTo(Span<T> destination)
+        //{
+        //    bool retVal = false;
+        //    if ((uint)_length <= (uint)destination.Length)
+        //    {
+        //        Buffer.Memmove(ref destination._reference, ref _reference, (uint)_length);
+        //        retVal = true;
+        //    }
+        //    return retVal;
+        //}
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public ReadOnlySpan<T> Slice(int start)
+        {
+            if ((uint)start > (uint)_length)
+                ThrowHelper.ThrowArgumentOutOfRangeException();
+
+            return new ReadOnlySpan<T>(_array, _start + start, _length - start);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public ReadOnlySpan<T> Slice(int start, int length)
+        {
+            if ((uint)start > (uint)_length || (uint)length > (uint)(_length - start))
+                ThrowHelper.ThrowArgumentOutOfRangeException();
+
+            return new ReadOnlySpan<T>(_array, _start + start, length);
+        }
+
+        public T[] ToArray()
+        {
+            if (_length == 0)
+                return Array.Empty<T>();
+            var result = new T[_length];
+            Array.Copy(_array, _start, result, 0, _length);
+            return result;
+        }
+        #endregion
+    }
+}
+#endif

src/Utils/ReadOnlySpanDummy.cs.meta

@@ -0,0 +1,11 @@
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