Merge branch 'release/3.1.x' into port/v3

Author: JimBobSquarePants

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter{TPixel}.cs

@@ -201,7 +201,8 @@ public override void PrepareForDecoding()
         this.pixelBuffer = allocator.Allocate2D<TPixel>(
             pixelSize.Width,
             pixelSize.Height,
-            this.Configuration.PreferContiguousImageBuffers);
+            this.Configuration.PreferContiguousImageBuffers,
+            AllocationOptions.Clean);
         this.paddedProxyPixelRow = allocator.Allocate<TPixel>(pixelSize.Width + 3);
 
         // Component processors from spectral to RGB

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -1983,6 +1983,9 @@ private IMemoryOwner<byte> ReadChunkData(int length)
         }
 
         // We rent the buffer here to return it afterwards in Decode()
+        // We don't want to throw a degenerated memory exception here as we want to allow partial decoding
+        // so limit the length.
+        length = (int)Math.Min(length, this.currentStream.Length - this.currentStream.Position);
         IMemoryOwner<byte> buffer = this.configuration.MemoryAllocator.Allocate<byte>(length, AllocationOptions.Clean);
 
         this.currentStream.Read(buffer.GetSpan(), 0, length);

src/ImageSharp/Formats/Png/PngScanlineProcessor.cs

@@ -181,11 +181,12 @@ public static void ProcessInterlacedPaletteScanline<TPixel>(
         ref TPixel rowSpanRef = ref MemoryMarshal.GetReference(rowSpan);
         ref Color paletteBase = ref MemoryMarshal.GetReference(palette.Value.Span);
         uint offset = pixelOffset + frameControl.XOffset;
+        int maxIndex = palette.Value.Length - 1;
 
         for (nuint x = offset, o = 0; x < frameControl.XMax; x += increment, o++)
         {
             uint index = Unsafe.Add(ref scanlineSpanRef, o);
-            Unsafe.Add(ref rowSpanRef, x) = TPixel.FromRgba32(Unsafe.Add(ref paletteBase, index).ToPixel<Rgba32>());
+            Unsafe.Add(ref rowSpanRef, x) = TPixel.FromRgba32(Unsafe.Add(ref paletteBase, (int)Math.Min(index, maxIndex)).ToPixel<Rgba32>());
         }
     }
 

src/ImageSharp/Formats/Tga/TgaDecoderCore.cs

@@ -84,7 +84,7 @@ public Image<TPixel> Decode<TPixel>(BufferedReadStream stream, CancellationToken
                 throw new UnknownImageFormatException("Width or height cannot be 0");
             }
 
-            Image<TPixel> image = Image.CreateUninitialized<TPixel>(this.configuration, this.fileHeader.Width, this.fileHeader.Height, this.metadata);
+            Image<TPixel> image = new(this.configuration, this.fileHeader.Width, this.fileHeader.Height, this.metadata);
             Buffer2D<TPixel> pixels = image.GetRootFramePixelBuffer();
 
             if (this.fileHeader.ColorMapType == 1)

src/ImageSharp/Memory/Allocators/Internals/UnmanagedMemoryHandle.cs

@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.Memory.Internals;
 internal struct UnmanagedMemoryHandle : IEquatable<UnmanagedMemoryHandle>
 {
     // Number of allocation re-attempts when detecting OutOfMemoryException.
-    private const int MaxAllocationAttempts = 1000;
+    private const int MaxAllocationAttempts = 10;
 
     // Track allocations for testing purposes:
     private static int totalOutstandingHandles;

src/ImageSharp/Memory/Allocators/MemoryAllocator.cs

@@ -2,6 +2,7 @@
 // Licensed under the Six Labors Split License.
 
 using System.Buffers;
+using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Memory;
 
@@ -10,6 +11,8 @@ namespace SixLabors.ImageSharp.Memory;
 /// </summary>
 public abstract class MemoryAllocator
 {
+    private const int OneGigabyte = 1 << 30;
+
     /// <summary>
     /// Gets the default platform-specific global <see cref="MemoryAllocator"/> instance that
     /// serves as the default value for <see cref="Configuration.MemoryAllocator"/>.
@@ -20,6 +23,10 @@ public abstract class MemoryAllocator
     /// </summary>
     public static MemoryAllocator Default { get; } = Create();
 
+    internal long MemoryGroupAllocationLimitBytes { get; private set; } = Environment.Is64BitProcess ? 4L * OneGigabyte : OneGigabyte;
+
+    internal int SingleBufferAllocationLimitBytes { get; private set; } = OneGigabyte;
+
     /// <summary>
     /// Gets the length of the largest contiguous buffer that can be handled by this allocator instance in bytes.
     /// </summary>
@@ -30,16 +37,24 @@ public abstract class MemoryAllocator
     /// Creates a default instance of a <see cref="MemoryAllocator"/> optimized for the executing platform.
     /// </summary>
     /// <returns>The <see cref="MemoryAllocator"/>.</returns>
-    public static MemoryAllocator Create() =>
-        new UniformUnmanagedMemoryPoolMemoryAllocator(null);
+    public static MemoryAllocator Create() => Create(default);
 
     /// <summary>
     /// Creates the default <see cref="MemoryAllocator"/> using the provided options.
     /// </summary>
     /// <param name="options">The <see cref="MemoryAllocatorOptions"/>.</param>
     /// <returns>The <see cref="MemoryAllocator"/>.</returns>
-    public static MemoryAllocator Create(MemoryAllocatorOptions options) =>
-        new UniformUnmanagedMemoryPoolMemoryAllocator(options.MaximumPoolSizeMegabytes);
+    public static MemoryAllocator Create(MemoryAllocatorOptions options)
+    {
+        UniformUnmanagedMemoryPoolMemoryAllocator allocator = new(options.MaximumPoolSizeMegabytes);
+        if (options.AllocationLimitMegabytes.HasValue)
+        {
+            allocator.MemoryGroupAllocationLimitBytes = options.AllocationLimitMegabytes.Value * 1024 * 1024;
+            allocator.SingleBufferAllocationLimitBytes = (int)Math.Min(allocator.SingleBufferAllocationLimitBytes, allocator.MemoryGroupAllocationLimitBytes);
+        }
+
+        return allocator;
+    }
 
     /// <summary>
     /// Allocates an <see cref="IMemoryOwner{T}" />, holding a <see cref="Memory{T}"/> of length <paramref name="length"/>.
@@ -64,15 +79,34 @@ public virtual void ReleaseRetainedResources()
     /// <summary>
     /// Allocates a <see cref="MemoryGroup{T}"/>.
     /// </summary>
+    /// <typeparam name="T">The type of element to allocate.</typeparam>
     /// <param name="totalLength">The total length of the buffer.</param>
     /// <param name="bufferAlignment">The expected alignment (eg. to make sure image rows fit into single buffers).</param>
     /// <param name="options">The <see cref="AllocationOptions"/>.</param>
     /// <returns>A new <see cref="MemoryGroup{T}"/>.</returns>
     /// <exception cref="InvalidMemoryOperationException">Thrown when 'blockAlignment' converted to bytes is greater than the buffer capacity of the allocator.</exception>
-    internal virtual MemoryGroup<T> AllocateGroup<T>(
+    internal MemoryGroup<T> AllocateGroup<T>(
         long totalLength,
         int bufferAlignment,
         AllocationOptions options = AllocationOptions.None)
         where T : struct
-        => MemoryGroup<T>.Allocate(this, totalLength, bufferAlignment, options);
+    {
+        if (totalLength < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(totalLength);
+        }
+
+        ulong totalLengthInBytes = (ulong)totalLength * (ulong)Unsafe.SizeOf<T>();
+        if (totalLengthInBytes > (ulong)this.MemoryGroupAllocationLimitBytes)
+        {
+            InvalidMemoryOperationException.ThrowAllocationOverLimitException(totalLengthInBytes, this.MemoryGroupAllocationLimitBytes);
+        }
+
+        // Cast to long is safe because we already checked that the total length is within the limit.
+        return this.AllocateGroupCore<T>(totalLength, (long)totalLengthInBytes, bufferAlignment, options);
+    }
+
+    internal virtual MemoryGroup<T> AllocateGroupCore<T>(long totalLengthInElements, long totalLengthInBytes, int bufferAlignment, AllocationOptions options)
+        where T : struct
+        => MemoryGroup<T>.Allocate(this, totalLengthInElements, bufferAlignment, options);
 }

src/ImageSharp/Memory/Allocators/MemoryAllocatorOptions.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
 namespace SixLabors.ImageSharp.Memory;
@@ -9,6 +9,7 @@ namespace SixLabors.ImageSharp.Memory;
 public struct MemoryAllocatorOptions
 {
     private int? maximumPoolSizeMegabytes;
+    private int? allocationLimitMegabytes;
 
     /// <summary>
     /// Gets or sets a value defining the maximum size of the <see cref="MemoryAllocator"/>'s internal memory pool
@@ -27,4 +28,22 @@ public int? MaximumPoolSizeMegabytes
             this.maximumPoolSizeMegabytes = value;
         }
     }
+
+    /// <summary>
+    /// Gets or sets a value defining the maximum (discontiguous) buffer size that can be allocated by the allocator in Megabytes.
+    /// <see langword="null"/> means platform default: 1GB on 32-bit processes, 4GB on 64-bit processes.
+    /// </summary>
+    public int? AllocationLimitMegabytes
+    {
+        get => this.allocationLimitMegabytes;
+        set
+        {
+            if (value.HasValue)
+            {
+                Guard.MustBeGreaterThan(value.Value, 0, nameof(this.AllocationLimitMegabytes));
+            }
+
+            this.allocationLimitMegabytes = value;
+        }
+    }
 }

src/ImageSharp/Memory/Allocators/SimpleGcMemoryAllocator.cs

@@ -1,7 +1,8 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
 using System.Buffers;
+using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Memory.Internals;
 
 namespace SixLabors.ImageSharp.Memory;
@@ -17,7 +18,16 @@ public sealed class SimpleGcMemoryAllocator : MemoryAllocator
     /// <inheritdoc />
     public override IMemoryOwner<T> Allocate<T>(int length, AllocationOptions options = AllocationOptions.None)
     {
-        Guard.MustBeGreaterThanOrEqualTo(length, 0, nameof(length));
+        if (length < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(length);
+        }
+
+        ulong lengthInBytes = (ulong)length * (ulong)Unsafe.SizeOf<T>();
+        if (lengthInBytes > (ulong)this.SingleBufferAllocationLimitBytes)
+        {
+            InvalidMemoryOperationException.ThrowAllocationOverLimitException(lengthInBytes, this.SingleBufferAllocationLimitBytes);
+        }
 
         return new BasicArrayBuffer<T>(new T[length]);
     }

src/ImageSharp/Memory/Allocators/UniformUnmanagedMemoryPoolMemoryAllocator.cs

@@ -83,10 +83,18 @@ public override IMemoryOwner<T> Allocate<T>(
         int length,
         AllocationOptions options = AllocationOptions.None)
     {
-        Guard.MustBeGreaterThanOrEqualTo(length, 0, nameof(length));
-        int lengthInBytes = length * Unsafe.SizeOf<T>();
+        if (length < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(length);
+        }
+
+        ulong lengthInBytes = (ulong)length * (ulong)Unsafe.SizeOf<T>();
+        if (lengthInBytes > (ulong)this.SingleBufferAllocationLimitBytes)
+        {
+            InvalidMemoryOperationException.ThrowAllocationOverLimitException(lengthInBytes, this.SingleBufferAllocationLimitBytes);
+        }
 
-        if (lengthInBytes <= this.sharedArrayPoolThresholdInBytes)
+        if (lengthInBytes <= (ulong)this.sharedArrayPoolThresholdInBytes)
         {
             var buffer = new SharedArrayPoolBuffer<T>(length);
             if (options.Has(AllocationOptions.Clean))
@@ -97,7 +105,7 @@ public override IMemoryOwner<T> Allocate<T>(
             return buffer;
         }
 
-        if (lengthInBytes <= this.poolBufferSizeInBytes)
+        if (lengthInBytes <= (ulong)this.poolBufferSizeInBytes)
         {
             UnmanagedMemoryHandle mem = this.pool.Rent();
             if (mem.IsValid)
@@ -111,20 +119,15 @@ public override IMemoryOwner<T> Allocate<T>(
     }
 
     /// <inheritdoc />
-    internal override MemoryGroup<T> AllocateGroup<T>(
-        long totalLength,
+    internal override MemoryGroup<T> AllocateGroupCore<T>(
+        long totalLengthInElements,
+        long totalLengthInBytes,
         int bufferAlignment,
         AllocationOptions options = AllocationOptions.None)
     {
-        long totalLengthInBytes = totalLength * Unsafe.SizeOf<T>();
-        if (totalLengthInBytes < 0)
-        {
-            throw new InvalidMemoryOperationException("Attempted to allocate a MemoryGroup of a size that is not representable.");
-        }
-
         if (totalLengthInBytes <= this.sharedArrayPoolThresholdInBytes)
         {
-            var buffer = new SharedArrayPoolBuffer<T>((int)totalLength);
+            var buffer = new SharedArrayPoolBuffer<T>((int)totalLengthInElements);
             return MemoryGroup<T>.CreateContiguous(buffer, options.Has(AllocationOptions.Clean));
         }
 
@@ -134,18 +137,18 @@ internal override MemoryGroup<T> AllocateGroup<T>(
             UnmanagedMemoryHandle mem = this.pool.Rent();
             if (mem.IsValid)
             {
-                UnmanagedBuffer<T> buffer = this.pool.CreateGuardedBuffer<T>(mem, (int)totalLength, options.Has(AllocationOptions.Clean));
+                UnmanagedBuffer<T> buffer = this.pool.CreateGuardedBuffer<T>(mem, (int)totalLengthInElements, options.Has(AllocationOptions.Clean));
                 return MemoryGroup<T>.CreateContiguous(buffer, options.Has(AllocationOptions.Clean));
             }
         }
 
         // Attempt to rent the whole group from the pool, allocate a group of unmanaged buffers if the attempt fails:
-        if (MemoryGroup<T>.TryAllocate(this.pool, totalLength, bufferAlignment, options, out MemoryGroup<T>? poolGroup))
+        if (MemoryGroup<T>.TryAllocate(this.pool, totalLengthInElements, bufferAlignment, options, out MemoryGroup<T>? poolGroup))
         {
             return poolGroup;
         }
 
-        return MemoryGroup<T>.Allocate(this.nonPoolAllocator, totalLength, bufferAlignment, options);
+        return MemoryGroup<T>.Allocate(this.nonPoolAllocator, totalLengthInElements, bufferAlignment, options);
     }
 
     public override void ReleaseRetainedResources() => this.pool.Release();

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroup{T}.cs

@@ -83,15 +83,16 @@ public static MemoryGroup<T> Allocate(
     {
         int bufferCapacityInBytes = allocator.GetBufferCapacityInBytes();
         Guard.NotNull(allocator, nameof(allocator));
-        Guard.MustBeGreaterThanOrEqualTo(totalLengthInElements, 0, nameof(totalLengthInElements));
-        Guard.MustBeGreaterThanOrEqualTo(bufferAlignmentInElements, 0, nameof(bufferAlignmentInElements));
 
-        int blockCapacityInElements = bufferCapacityInBytes / ElementSize;
+        if (totalLengthInElements < 0)
+        {
+            InvalidMemoryOperationException.ThrowNegativeAllocationException(totalLengthInElements);
+        }
 
-        if (bufferAlignmentInElements > blockCapacityInElements)
+        int blockCapacityInElements = bufferCapacityInBytes / ElementSize;
+        if (bufferAlignmentInElements < 0 || bufferAlignmentInElements > blockCapacityInElements)
         {
-            throw new InvalidMemoryOperationException(
-                $"The buffer capacity of the provided MemoryAllocator is insufficient for the requested buffer alignment: {bufferAlignmentInElements}.");
+            InvalidMemoryOperationException.ThrowInvalidAlignmentException(bufferAlignmentInElements);
         }
 
         if (totalLengthInElements == 0)