feat: native queue list

Runtime/Triangulator.cs

@@ -1266,6 +1266,56 @@ public static void DynamicInsertPoint(this UnsafeTriangulator<fp2> @this, Output
 #endif
     }
 
+    /// <summary>
+    /// Custom queue implementation which is a wrapper for <see cref="NativeList{T}"/>.
+    /// This implementation is memory <b>extensive</b>.
+    /// </summary>
+    internal struct NativeQueueList<T> : IDisposable where T : unmanaged
+    {
+        public readonly bool IsCreated => impl.IsCreated;
+        public readonly int Count => math.max(impl.Length - indexRef.Value, 0);
+
+        private NativeList<T> impl;
+        private NativeReference<int> indexRef;
+
+        public NativeQueueList(int capacity, Allocator allocator)
+        {
+            impl = new(capacity, allocator);
+            indexRef = new(0, allocator);
+        }
+
+        public NativeQueueList(Allocator allocator) : this(1, allocator) { }
+
+        public ReadOnlySpan<T> AsReadOnlySpan() => impl.AsReadOnly().AsReadOnlySpan()[indexRef.Value..];
+        public Span<T> AsSpan() => impl.AsArray().AsSpan()[indexRef.Value..];
+
+        public void Clear()
+        {
+            impl.Clear();
+            indexRef.Value = 0;
+        }
+
+        public void Dispose()
+        {
+            impl.Dispose();
+            indexRef.Dispose();
+        }
+
+        public void Enqueue(T item) => impl.Add(item);
+        public T Dequeue() => impl[indexRef.Value++];
+        public readonly bool IsEmpty() => Count == 0;
+        public bool TryDequeue(out T item)
+        {
+            var isEmpty = IsEmpty();
+            if (isEmpty)
+            {
+                Clear();
+            }
+            item = isEmpty ? default : Dequeue();
+            return !isEmpty;
+        }
+    }
+
     [BurstCompile]
     internal struct TriangulationJob<T, T2, TBig, TTransform, TUtils> : IJob
         where T : unmanaged, IComparable<T>

Tests/InternalUtilsTests.cs

@@ -1,6 +1,8 @@
 using andywiecko.BurstTriangulator.LowLevel.Unsafe;
 using NUnit.Framework;
+using System;
 using System.Linq;
+using Unity.Collections;
 using Unity.Mathematics;
 
 namespace andywiecko.BurstTriangulator.Editor.Tests
@@ -194,4 +196,136 @@ public void Area2Test(double2 a, double2 b, double2 c, double expected)
         [Test, TestCaseSource(nameof(pointInsideTriangleTestData))]
         public bool PointInsideTriangleTest(double2 p, double2 a, double2 b, double2 c) => default(UtilsDouble).PointInsideTriangle(p, a, b, c);
     }
+
+    public class NativeListQueueTests
+    {
+        [Test]
+        public void IsCreatedTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            Assert.That(queue.IsCreated, Is.True);
+        }
+
+        [Test]
+        public void CountTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+
+            var count0 = queue.Count;
+            queue.Enqueue(default);
+            queue.Enqueue(default);
+            queue.Enqueue(default);
+            var count3 = queue.Count;
+            queue.Dequeue();
+            queue.Dequeue();
+            var count1 = queue.Count;
+
+            Assert.That(count0, Is.EqualTo(0));
+            Assert.That(count3, Is.EqualTo(3));
+            Assert.That(count1, Is.EqualTo(1));
+        }
+
+        [Test]
+        public void AsReadOnlySpanTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(0);
+            queue.Enqueue(1);
+            queue.Enqueue(2);
+            queue.Enqueue(3);
+            queue.Dequeue();
+
+            var span = queue.AsReadOnlySpan();
+            Assert.That(span.ToArray(), Is.EqualTo(new[] { 1, 2, 3 }));
+        }
+
+        [Test]
+        public void AsSpanTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(0);
+            queue.Enqueue(1);
+            queue.Enqueue(2);
+            queue.Enqueue(3);
+            queue.Dequeue();
+
+            var span = queue.AsSpan();
+            Assert.That(span.ToArray(), Is.EqualTo(new[] { 1, 2, 3 }));
+        }
+
+        [Test]
+        public void ClearTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(0);
+            queue.Enqueue(1);
+            queue.Enqueue(2);
+            queue.Enqueue(3);
+
+            queue.Clear();
+
+            Assert.That(queue.Count, Is.EqualTo(0));
+            Assert.That(queue.AsReadOnlySpan().ToArray(), Is.Empty);
+        }
+
+        [Test]
+        public void DisposeTest()
+        {
+            var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Dispose();
+            Assert.That(queue.IsCreated, Is.False);
+        }
+
+        [Test]
+        public void EnqueueTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(42);
+            Assert.That(queue.AsReadOnlySpan()[0], Is.EqualTo(42));
+        }
+
+        [Test]
+        public void DequeueTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(1);
+            queue.Enqueue(2);
+            var el = queue.Dequeue();
+            Assert.That(el, Is.EqualTo(1));
+        }
+
+        [Test]
+        public void IsEmptyTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(1);
+            queue.Dequeue();
+            Assert.That(queue.IsEmpty(), Is.True);
+        }
+
+        [Test]
+        public void TryDequeueTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            queue.Enqueue(0);
+            queue.Enqueue(1);
+            queue.Enqueue(2);
+            queue.Enqueue(3);
+
+            using var tmp = new NativeList<int>(Allocator.Persistent);
+            while (queue.TryDequeue(out var el))
+            {
+                tmp.Add(el);
+            }
+
+            Assert.That(tmp.AsReadOnly(), Is.EqualTo(new[] { 0, 1, 2, 3 }));
+        }
+
+        [Test]
+        public void ThrowDequeueTest()
+        {
+            using var queue = new NativeQueueList<int>(Allocator.Persistent);
+            Assert.Throws<IndexOutOfRangeException>(() => queue.Dequeue());
+        }
+    }
 }