Merge pull request #1526 from jeffska/wrapmemory-size-guards

Change size guards for WrapMemory to allow Memory/IMemoryOwner blocks to be larger than the image size

Author: JimBobSquarePants

src/ImageSharp/Image.WrapMemory.cs

@@ -17,7 +17,7 @@ public abstract partial class Image
     {
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -52,15 +52,15 @@ public static Image<TPixel> WrapMemory<TPixel>(
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(metadata, nameof(metadata));
-            Guard.IsTrue(pixelMemory.Length == width * height, nameof(pixelMemory), "The length of the input memory doesn't match the specified image size");
+            Guard.IsTrue(pixelMemory.Length >= width * height, nameof(pixelMemory), "The length of the input memory is less than the specified image size");
 
             var memorySource = MemoryGroup<TPixel>.Wrap(pixelMemory);
             return new Image<TPixel>(configuration, memorySource, width, height, metadata);
         }
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -93,7 +93,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -122,7 +122,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
             => WrapMemory(Configuration.Default, pixelMemory, width, height);
 
         /// <summary>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels,
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels,
         /// allowing to view/manipulate it as an <see cref="Image{TPixel}"/> instance.
         /// The ownership of the <paramref name="pixelMemoryOwner"/> is being transferred to the new <see cref="Image{TPixel}"/> instance,
         /// meaning that the caller is not allowed to dispose <paramref name="pixelMemoryOwner"/>.
@@ -147,14 +147,14 @@ public static Image<TPixel> WrapMemory<TPixel>(
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(metadata, nameof(metadata));
-            Guard.IsTrue(pixelMemoryOwner.Memory.Length == width * height, nameof(pixelMemoryOwner), "The length of the input memory doesn't match the specified image size");
+            Guard.IsTrue(pixelMemoryOwner.Memory.Length >= width * height, nameof(pixelMemoryOwner), "The length of the input memory is less than the specified image size");
 
             var memorySource = MemoryGroup<TPixel>.Wrap(pixelMemoryOwner);
             return new Image<TPixel>(configuration, memorySource, width, height, metadata);
         }
 
         /// <summary>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels,
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels,
         /// allowing to view/manipulate it as an <see cref="Image{TPixel}"/> instance.
         /// The ownership of the <paramref name="pixelMemoryOwner"/> is being transferred to the new <see cref="Image{TPixel}"/> instance,
         /// meaning that the caller is not allowed to dispose <paramref name="pixelMemoryOwner"/>.
@@ -176,7 +176,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
             => WrapMemory(configuration, pixelMemoryOwner, width, height, new ImageMetadata());
 
         /// <summary>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels,
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels,
         /// allowing to view/manipulate it as an <see cref="Image{TPixel}"/> instance.
         /// The ownership of the <paramref name="pixelMemoryOwner"/> is being transferred to the new <see cref="Image{TPixel}"/> instance,
         /// meaning that the caller is not allowed to dispose <paramref name="pixelMemoryOwner"/>.
@@ -196,7 +196,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -234,15 +234,15 @@ public static Image<TPixel> WrapMemory<TPixel>(
 
             var memoryManager = new ByteMemoryManager<TPixel>(byteMemory);
 
-            Guard.IsTrue(memoryManager.Memory.Length == width * height, nameof(byteMemory), "The length of the input memory doesn't match the specified image size");
+            Guard.IsTrue(memoryManager.Memory.Length >= width * height, nameof(byteMemory), "The length of the input memory is less than the specified image size");
 
             var memorySource = MemoryGroup<TPixel>.Wrap(memoryManager.Memory);
             return new Image<TPixel>(configuration, memorySource, width, height, metadata);
         }
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -275,7 +275,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -305,7 +305,7 @@ public static Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -355,7 +355,7 @@ public static unsafe Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>
@@ -393,7 +393,7 @@ public static unsafe Image<TPixel> WrapMemory<TPixel>(
 
         /// <summary>
         /// <para>
-        /// Wraps an existing contiguous memory area of 'width' x 'height' pixels allowing viewing/manipulation as
+        /// Wraps an existing contiguous memory area of at least 'width' x 'height' pixels allowing viewing/manipulation as
         /// an <see cref="Image{TPixel}"/> instance.
         /// </para>
         /// <para>

tests/ImageSharp.Tests/Image/ImageTests.WrapMemory.cs

@@ -355,8 +355,6 @@ public unsafe void WrapSystemDrawingBitmap_FromPointer()
             [Theory]
             [InlineData(0, 5, 5)]
             [InlineData(20, 5, 5)]
-            [InlineData(26, 5, 5)]
-            [InlineData(2, 1, 1)]
             [InlineData(1023, 32, 32)]
             public void WrapMemory_MemoryOfT_InvalidSize(int size, int height, int width)
             {
@@ -366,6 +364,20 @@ public void WrapMemory_MemoryOfT_InvalidSize(int size, int height, int width)
                 Assert.Throws<ArgumentException>(() => Image.WrapMemory(memory, height, width));
             }
 
+            [Theory]
+            [InlineData(25, 5, 5)]
+            [InlineData(26, 5, 5)]
+            [InlineData(2, 1, 1)]
+            [InlineData(1024, 32, 32)]
+            [InlineData(2048, 32, 32)]
+            public void WrapMemory_MemoryOfT_ValidSize(int size, int height, int width)
+            {
+                var array = new Rgba32[size];
+                var memory = new Memory<Rgba32>(array);
+
+               Image.WrapMemory(memory, height, width);
+            }
+
             private class TestMemoryOwner<T> : IMemoryOwner<T>
             {
                 public Memory<T> Memory { get; set; }
@@ -378,8 +390,6 @@ public void Dispose()
             [Theory]
             [InlineData(0, 5, 5)]
             [InlineData(20, 5, 5)]
-            [InlineData(26, 5, 5)]
-            [InlineData(2, 1, 1)]
             [InlineData(1023, 32, 32)]
             public void WrapMemory_IMemoryOwnerOfT_InvalidSize(int size, int height, int width)
             {
@@ -390,10 +400,22 @@ public void WrapMemory_IMemoryOwnerOfT_InvalidSize(int size, int height, int wid
             }
 
             [Theory]
-            [InlineData(0, 5, 5)]
-            [InlineData(20, 5, 5)]
+            [InlineData(25, 5, 5)]
             [InlineData(26, 5, 5)]
             [InlineData(2, 1, 1)]
+            [InlineData(1024, 32, 32)]
+            [InlineData(2048, 32, 32)]
+            public void WrapMemory_IMemoryOwnerOfT_ValidSize(int size, int height, int width)
+            {
+                var array = new Rgba32[size];
+                var memory = new TestMemoryOwner<Rgba32> { Memory = array };
+
+                Image.WrapMemory(memory, height, width);
+            }
+
+            [Theory]
+            [InlineData(0, 5, 5)]
+            [InlineData(20, 5, 5)]
             [InlineData(1023, 32, 32)]
             public void WrapMemory_MemoryOfByte_InvalidSize(int size, int height, int width)
             {
@@ -403,6 +425,20 @@ public void WrapMemory_MemoryOfByte_InvalidSize(int size, int height, int width)
                 Assert.Throws<ArgumentException>(() => Image.WrapMemory<Rgba32>(memory, height, width));
             }
 
+            [Theory]
+            [InlineData(25, 5, 5)]
+            [InlineData(26, 5, 5)]
+            [InlineData(2, 1, 1)]
+            [InlineData(1024, 32, 32)]
+            [InlineData(2048, 32, 32)]
+            public void WrapMemory_MemoryOfByte_ValidSize(int size, int height, int width)
+            {
+                var array = new byte[size * Unsafe.SizeOf<Rgba32>()];
+                var memory = new Memory<byte>(array);
+
+                Image.WrapMemory<Rgba32>(memory, height, width);
+            }
+
             [Theory]
             [InlineData(0, 5, 5)]
             [InlineData(20, 5, 5)]