clean up Buffer<T> API

src/ImageSharp/Memory/Buffer2D{T}.cs

@@ -21,7 +21,7 @@ namespace SixLabors.ImageSharp.Memory
         /// <param name="wrappedBuffer">The buffer to wrap</param>
         /// <param name="width">The number of elements in a row</param>
         /// <param name="height">The number of rows</param>
-        public Buffer2D(Buffer<T> wrappedBuffer, int width, int height)
+        public Buffer2D(IBuffer<T> wrappedBuffer, int width, int height)
         {
             this.Buffer = wrappedBuffer;
             this.Width = width;
@@ -36,7 +36,7 @@ namespace SixLabors.ImageSharp.Memory
 
         public Span<T> Span => this.Buffer.Span;
 
-        public Buffer<T> Buffer { get; }
+        public IBuffer<T> Buffer { get; }
 
         /// <summary>
         /// Gets a reference to the element at the specified position.

src/ImageSharp/Memory/Buffer{T}.cs

@@ -18,16 +18,6 @@ namespace SixLabors.ImageSharp.Memory
     {
         private MemoryManager memoryManager;
 
-        /// <summary>
-        /// A pointer to the first element of <see cref="array"/> when pinned.
-        /// </summary>
-        private IntPtr pointer;
-
-        /// <summary>
-        /// A handle that allows to access the managed <see cref="array"/> as an unmanaged memory by pinning.
-        /// </summary>
-        private GCHandle handle;
-
         // why is there such a rule? :S Protected should be fine for a field!
 #pragma warning disable SA1401 // Fields should be private
         /// <summary>
@@ -36,22 +26,7 @@ namespace SixLabors.ImageSharp.Memory
         protected T[] array;
 #pragma warning restore SA1401 // Fields should be private
 
-        /// <summary>
+        internal Buffer(T[] array, int length, MemoryManager memoryManager)
-        /// Initializes a new instance of the <see cref="Buffer{T}"/> class.
-        /// </summary>
-        /// <param name="array">The array to pin.</param>
-        public Buffer(T[] array)
-        {
-            this.Length = array.Length;
-            this.array = array;
-        }
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Buffer{T}"/> class.
-        /// </summary>
-        /// <param name="array">The array to pin.</param>
-        /// <param name="length">The count of "relevant" elements in 'array'.</param>
-        public Buffer(T[] array, int length)
         {
             if (array.Length < length)
             {
@@ -60,22 +35,9 @@ namespace SixLabors.ImageSharp.Memory
 
             this.Length = length;
             this.array = array;
-        }
-
-        internal Buffer(T[] array, int length, MemoryManager memoryManager)
-            : this(array, length)
-        {
             this.memoryManager = memoryManager;
         }
 
-        /// <summary>
-        /// Finalizes an instance of the <see cref="Buffer{T}"/> class.
-        /// </summary>
-        ~Buffer()
-        {
-            this.UnPin();
-        }
-
         /// <summary>
         /// Gets a value indicating whether this <see cref="Buffer{T}"/> instance is disposed, or has lost ownership of <see cref="array"/>.
         /// </summary>
@@ -140,7 +102,6 @@ namespace SixLabors.ImageSharp.Memory
             }
 
             this.IsDisposedOrLostArrayOwnership = true;
-            this.UnPin();
 
             this.memoryManager?.Release(this);
 
@@ -166,33 +127,10 @@ namespace SixLabors.ImageSharp.Memory
             }
 
             this.IsDisposedOrLostArrayOwnership = true;
-            this.UnPin();
+            T[] a = this.array;
-            T[] array = this.array;
             this.array = null;
             this.memoryManager = null;
-            return array;
+            return a;
-        }
-
-        /// <summary>
-        /// Pins <see cref="array"/>.
-        /// </summary>
-        /// <returns>The pinned pointer</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public IntPtr Pin()
-        {
-            if (this.IsDisposedOrLostArrayOwnership)
-            {
-                throw new InvalidOperationException(
-                    "Pin() is invalid on a buffer with IsDisposedOrLostArrayOwnership == true!");
-            }
-
-            if (this.pointer == IntPtr.Zero)
-            {
-                this.handle = GCHandle.Alloc(this.array, GCHandleType.Pinned);
-                this.pointer = this.handle.AddrOfPinnedObject();
-            }
-
-            return this.pointer;
         }
 
         /// <summary>
@@ -202,20 +140,5 @@ namespace SixLabors.ImageSharp.Memory
         {
             return this.array;
         }
-
-        /// <summary>
-        /// Unpins <see cref="array"/>.
-        /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private void UnPin()
-        {
-            if (this.pointer == IntPtr.Zero || !this.handle.IsAllocated)
-            {
-                return;
-            }
-
-            this.handle.Free();
-            this.pointer = IntPtr.Zero;
-        }
     }
 }

src/ImageSharp/Memory/SimpleManagedMemoryManager.cs

@@ -8,7 +8,7 @@
         /// <inheritdoc />
         internal override Buffer<T> Allocate<T>(int length, bool clear)
         {
-            return new Buffer<T>(new T[length], length);
+            return new Buffer<T>(new T[length], length, this);
         }
 
         internal override IManagedByteBuffer AllocateManagedByteBuffer(int length, bool clear)

src/ImageSharp/Processing/Processors/Transforms/WeightsWindow.cs

@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         /// <summary>
         /// The buffer containing the weights values.
         /// </summary>
-        private readonly Buffer<float> buffer;
+        private readonly IBuffer<float> buffer;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="WeightsWindow"/> struct.
@@ -57,7 +57,8 @@ namespace SixLabors.ImageSharp.Processing.Processors
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public ref float GetStartReference()
         {
-            return ref this.buffer[this.flatStartIndex];
+            Span<float> span = this.buffer.Span;
+            return ref span[this.flatStartIndex];
         }
 
         /// <summary>

tests/ImageSharp.Benchmarks/Color/Bulk/PackFromVector4ReferenceVsPointer.cs

@@ -1,77 +0,0 @@
-namespace SixLabors.ImageSharp.Benchmarks
-{
-    using System.Numerics;
-    using System.Runtime.CompilerServices;
-
-    using BenchmarkDotNet.Attributes;
-
-    using SixLabors.ImageSharp;
-    using SixLabors.ImageSharp.Memory;
-
-    /// <summary>
-    /// Compares two implementation candidates for general BulkPixelOperations.ToVector4():
-    /// - One iterating with pointers
-    /// - One iterating with ref locals
-    /// </summary>
-    public unsafe class PackFromVector4ReferenceVsPointer
-    {
-        private Buffer<Rgba32> destination;
-
-        private Buffer<Vector4> source;
-
-        [Params(16, 128, 1024)]
-        public int Count { get; set; }
-
-        [GlobalSetup]
-        public void Setup()
-        {
-            this.destination = Configuration.Default.MemoryManager.Allocate<Rgba32>(this.Count);
-            this.source = Configuration.Default.MemoryManager.Allocate<Vector4>(this.Count * 4);
-            this.source.Pin();
-            this.destination.Pin();
-        }
-
-        [GlobalCleanup]
-        public void Cleanup()
-        {
-            this.source.Dispose();
-            this.destination.Dispose();
-        }
-
-        [Benchmark(Baseline = true)]
-        public void PackUsingPointers()
-        {
-            Vector4* sp = (Vector4*)this.source.Pin();
-            byte* dp = (byte*)this.destination.Pin();
-            int count = this.Count;
-            int size = sizeof(Rgba32);
-
-            for (int i = 0; i < count; i++)
-            {
-                Vector4 v = Unsafe.Read<Vector4>(sp);
-                Rgba32 c = default(Rgba32);
-                c.PackFromVector4(v);
-                Unsafe.Write(dp, c);
-
-                sp++;
-                dp += size;
-            }
-        }
-
-        [Benchmark]
-        public void PackUsingReferences()
-        {
-            ref Vector4 sp = ref this.source.DangerousGetPinnableReference();
-            ref Rgba32 dp = ref this.destination.DangerousGetPinnableReference();
-            int count = this.Count;
-
-            for (int i = 0; i < count; i++)
-            {
-                dp.PackFromVector4(sp);
-
-                sp = Unsafe.Add(ref sp, 1);
-                dp = Unsafe.Add(ref dp, 1);
-            }
-        }
-    }
-}

tests/ImageSharp.Benchmarks/General/IterateArray.cs

@@ -1,73 +0,0 @@
-namespace SixLabors.ImageSharp.Benchmarks.General
-{
-    using System.Numerics;
-    using System.Runtime.CompilerServices;
-
-    using BenchmarkDotNet.Attributes;
-
-    using SixLabors.ImageSharp.Memory;
-
-    public class IterateArray
-    {
-        // Usual pinned stuff
-        private Buffer<Vector4> buffer;
-
-        // An array that's not pinned by intent!
-        private Vector4[] array;
-        
-        [Params(64, 1024)]
-        public int Length { get; set; }
-
-        [GlobalSetup]
-        public void Setup()
-        {
-            this.buffer = Configuration.Default.MemoryManager.Allocate<Vector4>(this.Length);
-            this.buffer.Pin();
-            this.array = new Vector4[this.Length];
-        }
-
-        [Benchmark(Baseline = true)]
-        public Vector4 IterateIndexed()
-        {
-            Vector4 sum = new Vector4();
-            Vector4[] a = this.array;
-
-            for (int i = 0; i < a.Length; i++)
-            {
-                sum += a[i];
-            }
-            return sum;
-        }
-
-        [Benchmark]
-        public unsafe Vector4 IterateUsingPointers()
-        {
-            Vector4 sum = new Vector4();
-
-            Vector4* ptr = (Vector4*) this.buffer.Pin();
-            Vector4* end = ptr + this.Length;
-
-            for (; ptr < end; ptr++)
-            {
-                sum += *ptr;
-            }
-
-            return sum;
-        }
-
-        [Benchmark]
-        public Vector4 IterateUsingReferences()
-        {
-            Vector4 sum = new Vector4();
-
-            ref Vector4 start = ref this.array[0];
-
-            for (int i = 0; i < this.Length; i++)
-            {
-                sum += Unsafe.Add(ref start, i);
-            }
-
-            return sum;
-        }
-    }
-}

tests/ImageSharp.Tests/Formats/Jpg/JpegColorConverterTests.cs

@@ -289,7 +289,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                 }
 
                 // no need to dispose when buffer is not array owner
-                buffers[i] = new Buffer2D<float>(new Buffer<float>(values, values.Length), values.Length, 1);
+                buffers[i] = new Buffer2D<float>(new FakeBuffer<float>(values), values.Length, 1);
             }
             return new JpegColorConverter.ComponentValues(buffers, 0);
         }

tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs

@@ -106,7 +106,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                 this.Output.WriteLine($"Component{i}: {diff}");
                 averageDifference += diff.average;
                 totalDifference += diff.total;
-                tolerance += libJpegComponent.SpectralBlocks.Buffer.Length;
+                tolerance += libJpegComponent.SpectralBlocks.Buffer.Span.Length;
             }
             averageDifference /= componentCount;
 

tests/ImageSharp.Tests/Memory/Buffer2DTests.cs

@@ -16,11 +16,11 @@ namespace SixLabors.ImageSharp.Tests.Memory
         // ReSharper disable once ClassNeverInstantiated.Local
         private class Assert : Xunit.Assert
         {
-            public static void SpanPointsTo<T>(Span<T> span, Buffer<T> buffer, int bufferOffset = 0)
+            public static void SpanPointsTo<T>(Span<T> span, IBuffer<T> buffer, int bufferOffset = 0)
                 where T : struct
             {
                 ref T actual = ref span.DangerousGetPinnableReference();
-                ref T expected = ref Unsafe.Add(ref buffer[0], bufferOffset);
+                ref T expected = ref Unsafe.Add(ref buffer.DangerousGetPinnableReference(), bufferOffset);
 
                 Assert.True(Unsafe.AreSame(ref expected, ref actual), "span does not point to the expected position");
             }
@@ -35,7 +35,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
             {
                 Assert.Equal(width, buffer.Width);
                 Assert.Equal(height, buffer.Height);
-                Assert.Equal(width * height, buffer.Buffer.Length);
+                Assert.Equal(width * height, buffer.Buffer.Length());
             }
         }
 
@@ -47,7 +47,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
                 using (Buffer2D<int> buffer = Configuration.Default.MemoryManager.Allocate2D<int>(42, 42, true))
                 {
                     Span<int> span = buffer.Span;
-                    for (int j = 0; j < buffer.Buffer.Length; j++)
+                    for (int j = 0; j < span.Length; j++)
                     {
                         Assert.Equal(0, span[j]);
                         span[j] = 666;

tests/ImageSharp.Tests/PixelFormats/PixelOperationsTests.cs

@@ -333,25 +333,23 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats
             where TSource : struct
             where TDest : struct
         {
-            public Buffer<TSource> SourceBuffer { get; }
+            public TSource[] SourceBuffer { get; }
             public Buffer<TDest> ActualDestBuffer { get; }
-            public Buffer<TDest> ExpectedDestBuffer { get; }
+            public TDest[] ExpectedDestBuffer { get; }
 
             public Span<TSource> Source => this.SourceBuffer;
             public Span<TDest> ActualDest => this.ActualDestBuffer;
 
             public TestBuffers(TSource[] source, TDest[] expectedDest)
             {
-                this.SourceBuffer = new Buffer<TSource>(source);
+                this.SourceBuffer = source;
-                this.ExpectedDestBuffer = new Buffer<TDest>(expectedDest);
+                this.ExpectedDestBuffer = expectedDest;
                 this.ActualDestBuffer = Configuration.Default.MemoryManager.Allocate<TDest>(expectedDest.Length);
             }
 
             public void Dispose()
             {
-                this.SourceBuffer.Dispose();
                 this.ActualDestBuffer.Dispose();
-                this.ExpectedDestBuffer.Dispose();
             }
 
             private const float Tolerance = 0.0001f;
@@ -363,7 +361,7 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats
                 if (typeof(TDest) == typeof(Vector4))
                 {
                     
-                    Span<Vector4> expected = this.ExpectedDestBuffer.Span.NonPortableCast<TDest, Vector4>();
+                    Span<Vector4> expected = this.ExpectedDestBuffer.AsSpan().NonPortableCast<TDest, Vector4>();
                     Span<Vector4> actual = this.ActualDestBuffer.Span.NonPortableCast<TDest, Vector4>();
 
                     for (int i = 0; i < count; i++)
@@ -375,7 +373,7 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats
                 }
                 else
                 {
-                    Span<TDest> expected = this.ExpectedDestBuffer.Span;
+                    Span<TDest> expected = this.ExpectedDestBuffer.AsSpan();
                     Span<TDest> actual = this.ActualDestBuffer.Span;
                     for (int i = 0; i < count; i++)
                     {
@@ -388,7 +386,7 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats
         internal static void TestOperation<TSource, TDest>(
             TSource[] source,
             TDest[] expected,
-            Action<Buffer<TSource>, Buffer<TDest>> action)
+            Action<TSource[], Buffer<TDest>> action)
             where TSource : struct
             where TDest : struct
         {

tests/ImageSharp.Tests/TestUtilities/ReferenceCodecs/SystemDrawingBridge.cs

@@ -96,18 +96,20 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs
 
             var image = new Image<TPixel>(w, h);
 
-            using (var workBuffer = Configuration.Default.MemoryManager.Allocate<Argb32>(w))
+            using (IBuffer<Argb32> workBuffer = Configuration.Default.MemoryManager.Allocate<Argb32>(w))
             {
-                var destPtr = (Argb32*)workBuffer.Pin();
+                fixed (Argb32* destPtr = &workBuffer.DangerousGetPinnableReference())
-                for (int y = 0; y < h; y++)
                 {
-                    Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
+                    for (int y = 0; y < h; y++)
+                    {
+                        Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
 
-                    byte* sourcePtr = sourcePtrBase + data.Stride * y;
+                        byte* sourcePtr = sourcePtrBase + data.Stride * y;
 
-                    Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
+                        Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
 
-                    FromArgb32(workBuffer, row);
+                        FromArgb32(workBuffer.Span, row);
+                    }
                 }
             }
 
@@ -138,18 +140,20 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs
 
             var image = new Image<TPixel>(w, h);
 
-            using (var workBuffer = Configuration.Default.MemoryManager.Allocate<Rgb24>(w))
+            using (IBuffer<Rgb24> workBuffer = Configuration.Default.MemoryManager.Allocate<Rgb24>(w))
             {
-                var destPtr = (Rgb24*)workBuffer.Pin();
+                fixed (Rgb24* destPtr = &workBuffer.DangerousGetPinnableReference())
-                for (int y = 0; y < h; y++)
                 {
-                    Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
+                    for (int y = 0; y < h; y++)
+                    {
+                        Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
 
-                    byte* sourcePtr = sourcePtrBase + data.Stride * y;
+                        byte* sourcePtr = sourcePtrBase + data.Stride * y;
 
-                    Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
+                        Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
 
-                    FromRgb24(workBuffer, row);
+                        FromRgb24(workBuffer.Span, row);
+                    }
                 }
             }
 
@@ -170,17 +174,19 @@ namespace SixLabors.ImageSharp.Tests.TestUtilities.ReferenceCodecs
             long destRowByteCount = data.Stride;
             long sourceRowByteCount = w * sizeof(Argb32);
 
-            using (var workBuffer = Configuration.Default.MemoryManager.Allocate<Argb32>(w))
+            using (IBuffer<Argb32> workBuffer = image.GetConfiguration().MemoryManager.Allocate<Argb32>(w))
             {
-                var sourcePtr = (Argb32*)workBuffer.Pin();
+                fixed (Argb32* sourcePtr = &workBuffer.DangerousGetPinnableReference())
-
-                for (int y = 0; y < h; y++)
                 {
-                    Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
-                    ToArgb32(row, workBuffer);
-                    byte* destPtr = destPtrBase + data.Stride * y;
 
-                    Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
+                    for (int y = 0; y < h; y++)
+                    {
+                        Span<TPixel> row = image.Frames.RootFrame.GetPixelRowSpan(y);
+                        ToArgb32(row, workBuffer.Span);
+                        byte* destPtr = destPtrBase + data.Stride * y;
+
+                        Buffer.MemoryCopy(sourcePtr, destPtr, destRowByteCount, sourceRowByteCount);
+                    }
                 }
             }
 

tests/ImageSharp.Tests/TestUtilities/TestImageExtensions.cs

@@ -151,7 +151,7 @@ namespace SixLabors.ImageSharp.Tests
             bool appendPixelTypeToFileName = true)
             where TPixel : struct, IPixel<TPixel>
         {
-            using (Image<TPixel> firstFrameOnlyImage = new Image<TPixel>(image.Width, image.Height))
+            using (var firstFrameOnlyImage = new Image<TPixel>(image.Width, image.Height))
             using (Image<TPixel> referenceImage = GetReferenceOutputImage<TPixel>(
                 provider,
                 testOutputDetails,
@@ -378,9 +378,11 @@ namespace SixLabors.ImageSharp.Tests
 
             Span<Rgba32> pixels = image.Frames.RootFrame.GetPixelSpan();
 
-            for (int i = 0; i < buffer.Buffer.Length; i++)
+            Span<float> bufferSpan = buffer.Span;
+
+            for (int i = 0; i < bufferSpan.Length; i++)
             {
-                float value = buffer.Buffer[i] * scale;
+                float value = bufferSpan[i] * scale;
                 var v = new Vector4(value, value, value, 1f);
                 pixels[i].PackFromVector4(v);
             }