Use explicit stream instance in core decoders.

src/ImageSharp/Formats/Bmp/BmpDecoder.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -29,7 +30,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         public RleSkippedPixelHandling RleSkippedPixelHandling { get; set; } = RleSkippedPixelHandling.Black;
 
         /// <inheritdoc/>
-        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -38,7 +39,8 @@ namespace SixLabors.ImageSharp.Formats.Bmp
 
             try
             {
-                return await decoder.DecodeAsync<TPixel>(stream).ConfigureAwait(false);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return decoder.Decode<TPixel>(bufferedStream);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -49,7 +51,11 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         }
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
+        public Image Decode(Configuration configuration, Stream stream)
+            => this.Decode<Rgba32>(configuration, stream);
+
+        /// <inheritdoc/>
+        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
            where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -58,7 +64,8 @@ namespace SixLabors.ImageSharp.Formats.Bmp
 
             try
             {
-                return decoder.Decode<TPixel>(stream);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return await decoder.DecodeAsync<TPixel>(bufferedStream).ConfigureAwait(false);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -69,17 +76,16 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         }
 
         /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
+        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream)
-
+            => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
-        /// <inheritdoc />
-        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream) => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
 
         /// <inheritdoc/>
         public IImageInfo Identify(Configuration configuration, Stream stream)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new BmpDecoderCore(configuration, this).Identify(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return new BmpDecoderCore(configuration, this).Identify(bufferedStream);
         }
 
         /// <inheritdoc/>
@@ -87,7 +93,8 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new BmpDecoderCore(configuration, this).IdentifyAsync(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return new BmpDecoderCore(configuration, this).IdentifyAsync(bufferedStream);
         }
     }
 }

src/ImageSharp/Formats/Bmp/BmpDecoderCore.cs

@@ -4,10 +4,8 @@
 using System;
 using System.Buffers;
 using System.Buffers.Binary;
-using System.IO;
 using System.Numerics;
 using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
 using SixLabors.ImageSharp.Common.Helpers;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
@@ -62,7 +60,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         /// <summary>
         /// The stream to decode from.
         /// </summary>
-        private Stream stream;
+        private BufferedReadStream stream;
 
         /// <summary>
         /// The metadata.
@@ -120,7 +118,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         public Size Dimensions => new Size(this.infoHeader.Width, this.infoHeader.Height);
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Stream stream)
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             try
@@ -199,7 +197,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         }
 
         /// <inheritdoc />
-        public IImageInfo Identify(Stream stream)
+        public IImageInfo Identify(BufferedReadStream stream)
         {
             this.ReadImageHeaders(stream, out _, out _);
             return new ImageInfo(new PixelTypeInfo(this.infoHeader.BitsPerPixel), this.infoHeader.Width, this.infoHeader.Height, this.metadata);
@@ -1355,7 +1353,7 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         /// </summary>
         /// <returns>Bytes per color palette entry. Usually 4 bytes, but in case of Windows 2.x bitmaps or OS/2 1.x bitmaps
         /// the bytes per color palette entry's can be 3 bytes instead of 4.</returns>
-        private int ReadImageHeaders(Stream stream, out bool inverted, out byte[] palette)
+        private int ReadImageHeaders(BufferedReadStream stream, out bool inverted, out byte[] palette)
         {
             this.stream = stream;
 

src/ImageSharp/Formats/Gif/GifDecoder.cs

@@ -1,9 +1,9 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
-using System;
 using System.IO;
 using System.Threading.Tasks;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.PixelFormats;
@@ -26,14 +26,15 @@ namespace SixLabors.ImageSharp.Formats.Gif
         public FrameDecodingMode DecodingMode { get; set; } = FrameDecodingMode.All;
 
         /// <inheritdoc/>
-        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var decoder = new GifDecoderCore(configuration, this);
 
             try
             {
-                return await decoder.DecodeAsync<TPixel>(stream).ConfigureAwait(false);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return decoder.Decode<TPixel>(bufferedStream);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -47,14 +48,19 @@ namespace SixLabors.ImageSharp.Formats.Gif
         }
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
+        public Image Decode(Configuration configuration, Stream stream)
+            => this.Decode<Rgba32>(configuration, stream);
+
+        /// <inheritdoc/>
+        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var decoder = new GifDecoderCore(configuration, this);
 
             try
             {
-                return decoder.Decode<TPixel>(stream);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return await decoder.DecodeAsync<TPixel>(bufferedStream).ConfigureAwait(false);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -67,13 +73,19 @@ namespace SixLabors.ImageSharp.Formats.Gif
             }
         }
 
+        /// <inheritdoc />
+        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream)
+            => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
+
         /// <inheritdoc/>
         public IImageInfo Identify(Configuration configuration, Stream stream)
         {
             Guard.NotNull(stream, nameof(stream));
 
             var decoder = new GifDecoderCore(configuration, this);
-            return decoder.Identify(stream);
+
+            using var bufferedStream = new BufferedReadStream(stream);
+            return decoder.Identify(bufferedStream);
         }
 
         /// <inheritdoc/>
@@ -82,13 +94,9 @@ namespace SixLabors.ImageSharp.Formats.Gif
             Guard.NotNull(stream, nameof(stream));
 
             var decoder = new GifDecoderCore(configuration, this);
-            return decoder.IdentifyAsync(stream);
-        }
 
-        /// <inheritdoc />
+            using var bufferedStream = new BufferedReadStream(stream);
-        public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
+            return decoder.IdentifyAsync(bufferedStream);
-
+        }
-        /// <inheritdoc />
-        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream) => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
     }
 }

src/ImageSharp/Formats/Gif/GifDecoderCore.cs

@@ -27,7 +27,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// The currently loaded stream.
         /// </summary>
-        private Stream stream;
+        private BufferedReadStream stream;
 
         /// <summary>
         /// The global color table.
@@ -97,7 +97,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         private MemoryAllocator MemoryAllocator => this.Configuration.MemoryAllocator;
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Stream stream)
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Image<TPixel> image = null;
@@ -158,7 +158,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         }
 
         /// <inheritdoc />
-        public IImageInfo Identify(Stream stream)
+        public IImageInfo Identify(BufferedReadStream stream)
         {
             try
             {
@@ -572,7 +572,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// Reads the logical screen descriptor and global color table blocks
         /// </summary>
         /// <param name="stream">The stream containing image data. </param>
-        private void ReadLogicalScreenDescriptorAndGlobalColorTable(Stream stream)
+        private void ReadLogicalScreenDescriptorAndGlobalColorTable(BufferedReadStream stream)
         {
             this.stream = stream;
 

src/ImageSharp/Formats/Gif/LzwDecoder.cs

@@ -3,10 +3,9 @@
 
 using System;
 using System.Buffers;
-using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 
 namespace SixLabors.ImageSharp.Formats.Gif
@@ -29,7 +28,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// <summary>
         /// The stream to decode.
         /// </summary>
-        private readonly Stream stream;
+        private readonly BufferedReadStream stream;
 
         /// <summary>
         /// The prefix buffer.
@@ -52,8 +51,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
         /// </summary>
         /// <param name="memoryAllocator">The <see cref="MemoryAllocator"/> to use for buffer allocations.</param>
         /// <param name="stream">The stream to read from.</param>
-        /// <exception cref="System.ArgumentNullException"><paramref name="stream"/> is null.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="stream"/> is null.</exception>
-        public LzwDecoder(MemoryAllocator memoryAllocator, Stream stream)
+        public LzwDecoder(MemoryAllocator memoryAllocator, BufferedReadStream stream)
         {
             this.stream = stream ?? throw new ArgumentNullException(nameof(stream));
 

src/ImageSharp/Formats/IImageDecoderInternals.cs

@@ -1,7 +1,8 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
-using System.IO;
+using System;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats
@@ -21,18 +22,16 @@ namespace SixLabors.ImageSharp.Formats
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="stream">The stream, where the image should be decoded from. Cannot be null.</param>
-        /// <exception cref="System.ArgumentNullException">
+        /// <exception cref="ArgumentNullException"><paramref name="stream"/> is null.</exception>
-        ///    <para><paramref name="stream"/> is null.</para>
-        /// </exception>
         /// <returns>The decoded image.</returns>
-        Image<TPixel> Decode<TPixel>(Stream stream)
+        Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>;
 
         /// <summary>
         /// Reads the raw image information from the specified stream.
         /// </summary>
-        /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
+        /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
         /// <returns>The <see cref="IImageInfo"/>.</returns>
-        IImageInfo Identify(Stream stream);
+        IImageInfo Identify(BufferedReadStream stream);
     }
 }

src/ImageSharp/Formats/ImageDecoderUtilities.cs

@@ -1,9 +1,9 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
-using System.IO;
+using System;
 using System.Threading.Tasks;
-using SixLabors.ImageSharp.Memory;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats
@@ -14,42 +14,21 @@ namespace SixLabors.ImageSharp.Formats
         /// Reads the raw image information from the specified stream.
         /// </summary>
         /// <param name="decoder">The decoder.</param>
-        /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
+        /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
-        public static async Task<IImageInfo> IdentifyAsync(this IImageDecoderInternals decoder, Stream stream)
+        /// <exception cref="ArgumentNullException"><paramref name="stream"/> is null.</exception>
-        {
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
-            if (stream.CanSeek)
+        public static Task<IImageInfo> IdentifyAsync(this IImageDecoderInternals decoder, BufferedReadStream stream)
-            {
+            => Task.FromResult(decoder.Identify(stream));
-                return decoder.Identify(stream);
-            }
-
-            using MemoryStream ms = decoder.Configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
-            await stream.CopyToAsync(ms).ConfigureAwait(false);
-            ms.Position = 0;
-            return decoder.Identify(ms);
-        }
 
         /// <summary>
         /// Decodes the image from the specified stream.
         /// </summary>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <param name="decoder">The decoder.</param>
-        /// <param name="stream">The stream, where the image should be decoded from. Cannot be null.</param>
+        /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
-        /// <exception cref="System.ArgumentNullException">
+        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
-        ///    <para><paramref name="stream"/> is null.</para>
+        public static Task<Image<TPixel>> DecodeAsync<TPixel>(this IImageDecoderInternals decoder, BufferedReadStream stream)
-        /// </exception>
-        /// <returns>The decoded image.</returns>
-        public static async Task<Image<TPixel>> DecodeAsync<TPixel>(this IImageDecoderInternals decoder, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
-        {
+            => Task.FromResult(decoder.Decode<TPixel>(stream));
-            if (stream.CanSeek)
-            {
-                return decoder.Decode<TPixel>(stream);
-            }
-
-            using MemoryStream ms = decoder.Configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
-            await stream.CopyToAsync(ms).ConfigureAwait(false);
-            ms.Position = 0;
-            return decoder.Decode<TPixel>(ms);
-        }
     }
 }

src/ImageSharp/Formats/Jpeg/Components/Decoder/HuffmanScanBuffer.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
-using System.IO;
 using System.Runtime.CompilerServices;
+using SixLabors.ImageSharp.IO;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 {
@@ -11,7 +11,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
     /// </summary>
     internal struct HuffmanScanBuffer
     {
-        private readonly Stream stream;
+        private readonly BufferedReadStream stream;
 
         // The entropy encoded code buffer.
         private ulong data;
@@ -22,7 +22,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
         // Whether there is no more good data to pull from the stream for the current mcu.
         private bool badData;
 
-        public HuffmanScanBuffer(Stream stream)
+        public HuffmanScanBuffer(BufferedReadStream stream)
         {
             this.stream = stream;
             this.data = 0ul;

src/ImageSharp/Formats/Jpeg/Components/Decoder/HuffmanScanDecoder.cs

@@ -2,9 +2,9 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using SixLabors.ImageSharp.IO;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 {
@@ -18,7 +18,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
         private readonly JpegFrame frame;
         private readonly HuffmanTable[] dcHuffmanTables;
         private readonly HuffmanTable[] acHuffmanTables;
-        private readonly Stream stream;
+        private readonly BufferedReadStream stream;
         private readonly JpegComponent[] components;
 
         // The restart interval.
@@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
         /// <param name="successiveHigh">The successive approximation bit high end.</param>
         /// <param name="successiveLow">The successive approximation bit low end.</param>
         public HuffmanScanDecoder(
-            Stream stream,
+            BufferedReadStream stream,
             JpegFrame frame,
             HuffmanTable[] dcHuffmanTables,
             HuffmanTable[] acHuffmanTables,

src/ImageSharp/Formats/Jpeg/JpegDecoder.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -13,13 +14,11 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
     /// </summary>
     public sealed class JpegDecoder : IImageDecoder, IJpegDecoderOptions, IImageInfoDetector
     {
-        /// <summary>
+        /// <inheritdoc/>
-        /// Gets or sets a value indicating whether the metadata should be ignored when the image is being decoded.
-        /// </summary>
         public bool IgnoreMetadata { get; set; }
 
         /// <inheritdoc/>
-        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -27,7 +26,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             using var decoder = new JpegDecoderCore(configuration, this);
             try
             {
-                return await decoder.DecodeAsync<TPixel>(stream).ConfigureAwait(false);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return decoder.Decode<TPixel>(bufferedStream);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -41,7 +41,11 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         }
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
+        public Image Decode(Configuration configuration, Stream stream)
+            => this.Decode<Rgba32>(configuration, stream);
+
+        /// <inheritdoc/>
+        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -49,7 +53,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             using var decoder = new JpegDecoderCore(configuration, this);
             try
             {
-                return decoder.Decode<TPixel>(stream);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return await decoder.DecodeAsync<TPixel>(bufferedStream).ConfigureAwait(false);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -62,10 +67,6 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             }
         }
 
-        /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream)
-            => this.Decode<Rgba32>(configuration, stream);
-
         /// <inheritdoc />
         public async Task<Image> DecodeAsync(Configuration configuration, Stream stream)
             => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
@@ -75,21 +76,21 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         {
             Guard.NotNull(stream, nameof(stream));
 
-            using (var decoder = new JpegDecoderCore(configuration, this))
+            using var decoder = new JpegDecoderCore(configuration, this);
-            {
+            using var bufferedStream = new BufferedReadStream(stream);
-                return decoder.Identify(stream);
+
-            }
+            return decoder.Identify(bufferedStream);
         }
 
         /// <inheritdoc/>
-        public async Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream)
+        public Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            using (var decoder = new JpegDecoderCore(configuration, this))
+            using var decoder = new JpegDecoderCore(configuration, this);
-            {
+            using var bufferedStream = new BufferedReadStream(stream);
-                return await decoder.IdentifyAsync(stream).ConfigureAwait(false);
+
-            }
+            return decoder.IdentifyAsync(bufferedStream);
         }
     }
 }

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -3,13 +3,12 @@
 
 using System;
 using System.Buffers.Binary;
-using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using System.Threading.Tasks;
 using SixLabors.ImageSharp.Common.Helpers;
 using SixLabors.ImageSharp.Formats.Jpeg.Components;
 using SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
@@ -174,7 +173,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// <param name="marker">The buffer to read file markers to</param>
         /// <param name="stream">The input stream</param>
         /// <returns>The <see cref="JpegFileMarker"/></returns>
-        public static JpegFileMarker FindNextFileMarker(byte[] marker, Stream stream)
+        public static JpegFileMarker FindNextFileMarker(byte[] marker, BufferedReadStream stream)
         {
             int value = stream.Read(marker, 0, 2);
 
@@ -206,7 +205,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         }
 
         /// <inheritdoc/>
-        public Image<TPixel> Decode<TPixel>(Stream stream)
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             this.ParseStream(stream);
@@ -218,7 +217,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         }
 
         /// <inheritdoc/>
-        public IImageInfo Identify(Stream stream)
+        public IImageInfo Identify(BufferedReadStream stream)
         {
             this.ParseStream(stream, true);
             this.InitExifProfile();
@@ -234,7 +233,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream</param>
         /// <param name="metadataOnly">Whether to decode metadata only.</param>
-        public void ParseStream(Stream stream, bool metadataOnly = false)
+        public void ParseStream(BufferedReadStream stream, bool metadataOnly = false)
         {
             this.Metadata = new ImageMetadata();
 
@@ -497,7 +496,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessApplicationHeaderMarker(Stream stream, int remaining)
+        private void ProcessApplicationHeaderMarker(BufferedReadStream stream, int remaining)
         {
             // We can only decode JFif identifiers.
             if (remaining < JFifMarker.Length)
@@ -524,7 +523,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessApp1Marker(Stream stream, int remaining)
+        private void ProcessApp1Marker(BufferedReadStream stream, int remaining)
         {
             const int Exif00 = 6;
             if (remaining < Exif00 || this.IgnoreMetadata)
@@ -558,7 +557,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessApp2Marker(Stream stream, int remaining)
+        private void ProcessApp2Marker(BufferedReadStream stream, int remaining)
         {
             // Length is 14 though we only need to check 12.
             const int Icclength = 14;
@@ -601,7 +600,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessApp13Marker(Stream stream, int remaining)
+        private void ProcessApp13Marker(BufferedReadStream stream, int remaining)
         {
             if (remaining < ProfileResolver.AdobePhotoshopApp13Marker.Length || this.IgnoreMetadata)
             {
@@ -691,7 +690,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessApp14Marker(Stream stream, int remaining)
+        private void ProcessApp14Marker(BufferedReadStream stream, int remaining)
         {
             const int MarkerLength = AdobeMarker.Length;
             if (remaining < MarkerLength)
@@ -720,7 +719,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// <exception cref="ImageFormatException">
         /// Thrown if the tables do not match the header
         /// </exception>
-        private void ProcessDefineQuantizationTablesMarker(Stream stream, int remaining)
+        private void ProcessDefineQuantizationTablesMarker(BufferedReadStream stream, int remaining)
         {
             while (remaining > 0)
             {
@@ -806,7 +805,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// <param name="remaining">The remaining bytes in the segment block.</param>
         /// <param name="frameMarker">The current frame marker.</param>
         /// <param name="metadataOnly">Whether to parse metadata only</param>
-        private void ProcessStartOfFrameMarker(Stream stream, int remaining, in JpegFileMarker frameMarker, bool metadataOnly)
+        private void ProcessStartOfFrameMarker(BufferedReadStream stream, int remaining, in JpegFileMarker frameMarker, bool metadataOnly)
         {
             if (this.Frame != null)
             {
@@ -907,7 +906,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessDefineHuffmanTablesMarker(Stream stream, int remaining)
+        private void ProcessDefineHuffmanTablesMarker(BufferedReadStream stream, int remaining)
         {
             int length = remaining;
 
@@ -974,7 +973,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// </summary>
         /// <param name="stream">The input stream.</param>
         /// <param name="remaining">The remaining bytes in the segment block.</param>
-        private void ProcessDefineRestartIntervalMarker(Stream stream, int remaining)
+        private void ProcessDefineRestartIntervalMarker(BufferedReadStream stream, int remaining)
         {
             if (remaining != 2)
             {
@@ -988,7 +987,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// Processes the SOS (Start of scan marker).
         /// </summary>
         /// <param name="stream">The input stream.</param>
-        private void ProcessStartOfScanMarker(Stream stream)
+        private void ProcessStartOfScanMarker(BufferedReadStream stream)
         {
             if (this.Frame is null)
             {
@@ -1061,7 +1060,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         /// <param name="stream">The input stream.</param>
         /// <returns>The <see cref="ushort"/></returns>
         [MethodImpl(InliningOptions.ShortMethod)]
-        private ushort ReadUint16(Stream stream)
+        private ushort ReadUint16(BufferedReadStream stream)
         {
             stream.Read(this.markerBuffer, 0, 2);
             return BinaryPrimitives.ReadUInt16BigEndian(this.markerBuffer);

src/ImageSharp/Formats/Png/PngDecoder.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -13,26 +14,19 @@ namespace SixLabors.ImageSharp.Formats.Png
     /// </summary>
     public sealed class PngDecoder : IImageDecoder, IPngDecoderOptions, IImageInfoDetector
     {
-        /// <summary>
+        /// <inheritdoc/>
-        /// Gets or sets a value indicating whether the metadata should be ignored when the image is being decoded.
-        /// </summary>
         public bool IgnoreMetadata { get; set; }
 
-        /// <summary>
+        /// <inheritdoc/>
-        /// Decodes the image from the specified stream to the <see cref="ImageFrame{TPixel}"/>.
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
-        /// </summary>
-        /// <typeparam name="TPixel">The pixel format.</typeparam>
-        /// <param name="configuration">The configuration for the image.</param>
-        /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
-        /// <returns>The decoded image.</returns>
-        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var decoder = new PngDecoderCore(configuration, this);
 
             try
             {
-                return await decoder.DecodeAsync<TPixel>(stream).ConfigureAwait(false);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return decoder.Decode<TPixel>(bufferedStream);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -45,21 +39,19 @@ namespace SixLabors.ImageSharp.Formats.Png
             }
         }
 
-        /// <summary>
+        /// <inheritdoc />
-        /// Decodes the image from the specified stream to the <see cref="ImageFrame{TPixel}"/>.
+        public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
-        /// </summary>
+
-        /// <typeparam name="TPixel">The pixel format.</typeparam>
+        /// <inheritdoc/>
-        /// <param name="configuration">The configuration for the image.</param>
+        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
-        /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
-        /// <returns>The decoded image.</returns>
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var decoder = new PngDecoderCore(configuration, this);
 
             try
             {
-                return decoder.Decode<TPixel>(stream);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return await decoder.DecodeAsync<TPixel>(bufferedStream).ConfigureAwait(false);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -72,24 +64,23 @@ namespace SixLabors.ImageSharp.Formats.Png
             }
         }
 
+        /// <inheritdoc />
+        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream) => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
+
         /// <inheritdoc/>
         public IImageInfo Identify(Configuration configuration, Stream stream)
         {
             var decoder = new PngDecoderCore(configuration, this);
-            return decoder.Identify(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return decoder.Identify(bufferedStream);
         }
 
         /// <inheritdoc/>
         public Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream)
         {
             var decoder = new PngDecoderCore(configuration, this);
-            return decoder.IdentifyAsync(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return decoder.IdentifyAsync(bufferedStream);
         }
-
-        /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
-
-        /// <inheritdoc />
-        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream) => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
     }
 }

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -44,7 +44,7 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// <summary>
         /// The stream to decode from.
         /// </summary>
-        private Stream currentStream;
+        private BufferedReadStream currentStream;
 
         /// <summary>
         /// The png header.
@@ -132,7 +132,7 @@ namespace SixLabors.ImageSharp.Formats.Png
         public Size Dimensions => new Size(this.header.Width, this.header.Height);
 
         /// <inheritdoc/>
-        public Image<TPixel> Decode<TPixel>(Stream stream)
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var metadata = new ImageMetadata();
@@ -224,7 +224,7 @@ namespace SixLabors.ImageSharp.Formats.Png
         }
 
         /// <inheritdoc/>
-        public IImageInfo Identify(Stream stream)
+        public IImageInfo Identify(BufferedReadStream stream)
         {
             var metadata = new ImageMetadata();
             PngMetadata pngMetadata = metadata.GetPngMetadata();
@@ -499,7 +499,7 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// <param name="compressedStream">The compressed pixel data stream.</param>
         /// <param name="image">The image to decode to.</param>
         /// <param name="pngMetadata">The png metadata</param>
-        private void DecodePixelData<TPixel>(Stream compressedStream, ImageFrame<TPixel> image, PngMetadata pngMetadata)
+        private void DecodePixelData<TPixel>(DeflateStream compressedStream, ImageFrame<TPixel> image, PngMetadata pngMetadata)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             while (this.currentRow < this.header.Height)
@@ -555,7 +555,7 @@ namespace SixLabors.ImageSharp.Formats.Png
         /// <param name="compressedStream">The compressed pixel data stream.</param>
         /// <param name="image">The current image.</param>
         /// <param name="pngMetadata">The png metadata.</param>
-        private void DecodeInterlacedPixelData<TPixel>(Stream compressedStream, ImageFrame<TPixel> image, PngMetadata pngMetadata)
+        private void DecodeInterlacedPixelData<TPixel>(DeflateStream compressedStream, ImageFrame<TPixel> image, PngMetadata pngMetadata)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             int pass = 0;
@@ -1027,7 +1027,8 @@ namespace SixLabors.ImageSharp.Formats.Png
         private bool TryUncompressTextData(ReadOnlySpan<byte> compressedData, Encoding encoding, out string value)
         {
             using (var memoryStream = new MemoryStream(compressedData.ToArray()))
-            using (var inflateStream = new ZlibInflateStream(memoryStream))
+            using (var bufferedStream = new BufferedReadStream(memoryStream))
+            using (var inflateStream = new ZlibInflateStream(bufferedStream))
             {
                 if (!inflateStream.AllocateNewBytes(compressedData.Length, false))
                 {

src/ImageSharp/Formats/Png/Zlib/ZlibInflateStream.cs

@@ -4,6 +4,7 @@
 using System;
 using System.IO;
 using System.IO.Compression;
+using SixLabors.ImageSharp.IO;
 
 namespace SixLabors.ImageSharp.Formats.Png.Zlib
 {
@@ -27,7 +28,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// <summary>
         /// The inner raw memory stream.
         /// </summary>
-        private readonly Stream innerStream;
+        private readonly BufferedReadStream innerStream;
 
         /// <summary>
         /// A value indicating whether this instance of the given entity has been disposed.
@@ -56,7 +57,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// Initializes a new instance of the <see cref="ZlibInflateStream"/> class.
         /// </summary>
         /// <param name="innerStream">The inner raw stream.</param>
-        public ZlibInflateStream(Stream innerStream)
+        public ZlibInflateStream(BufferedReadStream innerStream)
             : this(innerStream, GetDataNoOp)
         {
         }
@@ -66,7 +67,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
         /// </summary>
         /// <param name="innerStream">The inner raw stream.</param>
         /// <param name="getData">A delegate to get more data from the inner stream.</param>
-        public ZlibInflateStream(Stream innerStream, Func<int> getData)
+        public ZlibInflateStream(BufferedReadStream innerStream, Func<int> getData)
         {
             this.innerStream = innerStream;
             this.getData = getData;
@@ -272,7 +273,7 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib
                 this.currentDataRemaining -= 4;
             }
 
-            // Initialize the deflate Stream.
+            // Initialize the deflate BufferedReadStream.
             this.CompressedStream = new DeflateStream(this, CompressionMode.Decompress, true);
 
             return true;

src/ImageSharp/Formats/Tga/TgaDecoder.cs

@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -14,7 +15,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
     public sealed class TgaDecoder : IImageDecoder, ITgaDecoderOptions, IImageInfoDetector
     {
         /// <inheritdoc/>
-        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
+        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -23,7 +24,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
 
             try
             {
-                return await decoder.DecodeAsync<TPixel>(stream).ConfigureAwait(false);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return decoder.Decode<TPixel>(bufferedStream);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -37,7 +39,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
         }
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
+        public Image Decode(Configuration configuration, Stream stream)
+            => this.Decode<Rgba32>(configuration, stream);
+
+        /// <inheritdoc/>
+        public async Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             Guard.NotNull(stream, nameof(stream));
@@ -46,7 +52,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
 
             try
             {
-                return decoder.Decode<TPixel>(stream);
+                using var bufferedStream = new BufferedReadStream(stream);
+                return await decoder.DecodeAsync<TPixel>(bufferedStream).ConfigureAwait(false);
             }
             catch (InvalidMemoryOperationException ex)
             {
@@ -60,17 +67,16 @@ namespace SixLabors.ImageSharp.Formats.Tga
         }
 
         /// <inheritdoc />
-        public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
+        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream)
-
+            => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
-        /// <inheritdoc />
-        public async Task<Image> DecodeAsync(Configuration configuration, Stream stream) => await this.DecodeAsync<Rgba32>(configuration, stream).ConfigureAwait(false);
 
         /// <inheritdoc/>
         public IImageInfo Identify(Configuration configuration, Stream stream)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new TgaDecoderCore(configuration, this).Identify(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return new TgaDecoderCore(configuration, this).Identify(bufferedStream);
         }
 
         /// <inheritdoc/>
@@ -78,7 +84,8 @@ namespace SixLabors.ImageSharp.Formats.Tga
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new TgaDecoderCore(configuration, this).IdentifyAsync(stream);
+            using var bufferedStream = new BufferedReadStream(stream);
+            return new TgaDecoderCore(configuration, this).IdentifyAsync(bufferedStream);
         }
     }
 }

src/ImageSharp/Formats/Tga/TgaDecoderCore.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Buffers;
-using System.IO;
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
@@ -45,7 +44,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
         /// <summary>
         /// The stream to decode from.
         /// </summary>
-        private Stream currentStream;
+        private BufferedReadStream currentStream;
 
         /// <summary>
         /// The bitmap decoder options.
@@ -78,7 +77,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
         public Size Dimensions => new Size(this.fileHeader.Width, this.fileHeader.Height);
 
         /// <inheritdoc />
-        public Image<TPixel> Decode<TPixel>(Stream stream)
+        public Image<TPixel> Decode<TPixel>(BufferedReadStream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             try
@@ -641,7 +640,7 @@ namespace SixLabors.ImageSharp.Formats.Tga
         }
 
         /// <inheritdoc />
-        public IImageInfo Identify(Stream stream)
+        public IImageInfo Identify(BufferedReadStream stream)
         {
             this.ReadFileHeader(stream);
             return new ImageInfo(
@@ -868,9 +867,9 @@ namespace SixLabors.ImageSharp.Formats.Tga
         /// <summary>
         /// Reads the tga file header from the stream.
         /// </summary>
-        /// <param name="stream">The <see cref="Stream"/> containing image data.</param>
+        /// <param name="stream">The <see cref="BufferedReadStream"/> containing image data.</param>
         /// <returns>The image origin.</returns>
-        private TgaImageOrigin ReadFileHeader(Stream stream)
+        private TgaImageOrigin ReadFileHeader(BufferedReadStream stream)
         {
             this.currentStream = stream;
 

src/ImageSharp/IO/BufferedReadStream.cs

@@ -157,14 +157,38 @@ namespace SixLabors.ImageSharp.IO
             return this.ReadToBufferViaCopyFast(buffer, offset, count);
         }
 
+#if SUPPORTS_SPAN_STREAM
+        /// <inheritdoc/>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public override int Read(Span<byte> buffer)
+        {
+            // Too big for our buffer. Read directly from the stream.
+            int count = buffer.Length;
+            if (count > BufferLength)
+            {
+                return this.ReadToBufferDirectSlow(buffer);
+            }
+
+            // Too big for remaining buffer but less than entire buffer length
+            // Copy to buffer then read from there.
+            if (count + this.readBufferIndex > BufferLength)
+            {
+                return this.ReadToBufferViaCopySlow(buffer);
+            }
+
+            return this.ReadToBufferViaCopyFast(buffer);
+        }
+#endif
+
         /// <inheritdoc/>
         public override void Flush()
         {
             // Reset the stream position to match reader position.
-            if (this.readerPosition != this.BaseStream.Position)
+            Stream baseStream = this.BaseStream;
+            if (this.readerPosition != baseStream.Position)
             {
-                this.BaseStream.Seek(this.readerPosition, SeekOrigin.Begin);
+                baseStream.Seek(this.readerPosition, SeekOrigin.Begin);
-                this.readerPosition = (int)this.BaseStream.Position;
+                this.readerPosition = (int)baseStream.Position;
             }
 
             // Reset to trigger full read on next attempt.
@@ -231,9 +255,10 @@ namespace SixLabors.ImageSharp.IO
         [MethodImpl(MethodImplOptions.NoInlining)]
         private void FillReadBuffer()
         {
-            if (this.readerPosition != this.BaseStream.Position)
+            Stream baseStream = this.BaseStream;
+            if (this.readerPosition != baseStream.Position)
             {
-                this.BaseStream.Seek(this.readerPosition, SeekOrigin.Begin);
+                baseStream.Seek(this.readerPosition, SeekOrigin.Begin);
             }
 
             // Read doesn't always guarantee the full returned length so read a byte
@@ -242,7 +267,7 @@ namespace SixLabors.ImageSharp.IO
             int i;
             do
             {
-                i = this.BaseStream.Read(this.readBuffer, n, BufferLength - n);
+                i = baseStream.Read(this.readBuffer, n, BufferLength - n);
                 n += i;
             }
             while (n < BufferLength && i > 0);
@@ -250,6 +275,20 @@ namespace SixLabors.ImageSharp.IO
             this.readBufferIndex = 0;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private int ReadToBufferViaCopyFast(Span<byte> buffer)
+        {
+            int n = this.GetCopyCount(buffer.Length);
+
+            // Just straight copy. MemoryStream does the same so should be fast enough.
+            this.readBuffer.AsSpan(this.readBufferIndex, n).CopyTo(buffer);
+
+            this.readerPosition += n;
+            this.readBufferIndex += n;
+
+            return n;
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private int ReadToBufferViaCopyFast(byte[] buffer, int offset, int count)
         {
@@ -262,6 +301,15 @@ namespace SixLabors.ImageSharp.IO
             return n;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private int ReadToBufferViaCopySlow(Span<byte> buffer)
+        {
+            // Refill our buffer then copy.
+            this.FillReadBuffer();
+
+            return this.ReadToBufferViaCopyFast(buffer);
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private int ReadToBufferViaCopySlow(byte[] buffer, int offset, int count)
         {
@@ -271,13 +319,41 @@ namespace SixLabors.ImageSharp.IO
             return this.ReadToBufferViaCopyFast(buffer, offset, count);
         }
 
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private int ReadToBufferDirectSlow(Span<byte> buffer)
+        {
+            // Read to target but don't copy to our read buffer.
+            Stream baseStream = this.BaseStream;
+            if (this.readerPosition != baseStream.Position)
+            {
+                baseStream.Seek(this.readerPosition, SeekOrigin.Begin);
+            }
+
+            // Read doesn't always guarantee the full returned length so read a byte
+            // at a time until we get either our count or hit the end of the stream.
+            int count = buffer.Length;
+            int n = 0;
+            int i;
+            do
+            {
+                i = baseStream.Read(buffer.Slice(n, count - n));
+                n += i;
+            }
+            while (n < count && i > 0);
+
+            this.Position += n;
+
+            return n;
+        }
+
         [MethodImpl(MethodImplOptions.NoInlining)]
         private int ReadToBufferDirectSlow(byte[] buffer, int offset, int count)
         {
             // Read to target but don't copy to our read buffer.
-            if (this.readerPosition != this.BaseStream.Position)
+            Stream baseStream = this.BaseStream;
+            if (this.readerPosition != baseStream.Position)
             {
-                this.BaseStream.Seek(this.readerPosition, SeekOrigin.Begin);
+                baseStream.Seek(this.readerPosition, SeekOrigin.Begin);
             }
 
             // Read doesn't always guarantee the full returned length so read a byte
@@ -286,7 +362,7 @@ namespace SixLabors.ImageSharp.IO
             int i;
             do
             {
-                i = this.BaseStream.Read(buffer, n + offset, count - n);
+                i = baseStream.Read(buffer, n + offset, count - n);
                 n += i;
             }
             while (n < count && i > 0);

src/ImageSharp/Image.FromStream.cs

@@ -7,7 +7,6 @@ using System.IO;
 using System.Text;
 using System.Threading.Tasks;
 using SixLabors.ImageSharp.Formats;
-using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -38,7 +37,7 @@ namespace SixLabors.ImageSharp
         /// <exception cref="NotSupportedException">The stream is not readable.</exception>
         /// <returns>The format type or null if none found.</returns>
         public static IImageFormat DetectFormat(Configuration configuration, Stream stream)
-            => WithSeekableStream(configuration, stream, s => InternalDetectFormat(s, configuration), false);
+            => WithSeekableStream(configuration, stream, s => InternalDetectFormat(s, configuration));
 
         /// <summary>
         /// By reading the header on the provided stream this calculates the images format type.
@@ -63,8 +62,7 @@ namespace SixLabors.ImageSharp
             => WithSeekableStreamAsync(
                 configuration,
                 stream,
-                s => InternalDetectFormatAsync(s, configuration),
+                s => InternalDetectFormatAsync(s, configuration));
-                false);
 
         /// <summary>
         /// Reads the raw image information from the specified stream without fully decoding it.
@@ -663,17 +661,11 @@ namespace SixLabors.ImageSharp
         /// <param name="configuration">The configuration.</param>
         /// <param name="stream">The input stream.</param>
         /// <param name="action">The action to perform.</param>
-        /// <param name="buffer">
-        /// Whether to buffer the input stream.
-        /// Short intial reads like <see cref="DetectFormat(Configuration, Stream)"/> do not require
-        /// the overhead of reading the stream to the buffer. Defaults to <see langword="true"/>.
-        /// </param>
         /// <returns>The <typeparamref name="T"/>.</returns>
         private static T WithSeekableStream<T>(
             Configuration configuration,
             Stream stream,
-            Func<Stream, T> action,
+            Func<Stream, T> action)
-            bool buffer = true)
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(stream, nameof(stream));
@@ -690,30 +682,16 @@ namespace SixLabors.ImageSharp
                     stream.Position = 0;
                 }
 
-                if (buffer)
-                {
-                    using var bufferedStream = new BufferedReadStream(stream);
-                    return action(bufferedStream);
-                }
-
                 return action(stream);
             }
 
             // We want to be able to load images from things like HttpContext.Request.Body
-            using (MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length))
+            using MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
-            {
             stream.CopyTo(memoryStream);
             memoryStream.Position = 0;
 
-                if (buffer)
-                {
-                    using var bufferedStream = new BufferedReadStream(memoryStream);
-                    return action(bufferedStream);
-                }
-
             return action(memoryStream);
         }
-        }
 
         /// <summary>
         /// Performs the given action asynchronously against the stream ensuring that it is seekable.
@@ -722,17 +700,11 @@ namespace SixLabors.ImageSharp
         /// <param name="configuration">The configuration.</param>
         /// <param name="stream">The input stream.</param>
         /// <param name="action">The action to perform.</param>
-        /// <param name="buffer">
-        /// Whether to buffer the input stream.
-        /// Short intial reads like <see cref="DetectFormat(Configuration, Stream)"/> do not require
-        /// the overhead of reading the stream to the buffer. Defaults to <see langword="true"/>.
-        /// </param>
         /// <returns>The <see cref="Task{T}"/>.</returns>
         private static async Task<T> WithSeekableStreamAsync<T>(
             Configuration configuration,
             Stream stream,
-            Func<Stream, Task<T>> action,
+            Func<Stream, Task<T>> action)
-            bool buffer = true)
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(stream, nameof(stream));
@@ -753,28 +725,14 @@ namespace SixLabors.ImageSharp
                     stream.Position = 0;
                 }
 
-                if (buffer)
-                {
-                    using var bufferedStream = new BufferedReadStream(stream);
-                    return await action(bufferedStream).ConfigureAwait(false);
-                }
-
                 return await action(stream).ConfigureAwait(false);
             }
 
-            using (MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length))
+            using MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
-            {
             await stream.CopyToAsync(memoryStream).ConfigureAwait(false);
             memoryStream.Position = 0;
 
-                if (buffer)
-                {
-                    using var bufferedStream = new BufferedReadStream(memoryStream);
-                    return await action(bufferedStream).ConfigureAwait(false);
-                }
-
             return await action(memoryStream).ConfigureAwait(false);
         }
     }
 }
-}

tests/ImageSharp.Benchmarks/Codecs/Jpeg/DecodeJpegParseStreamOnly.cs

@@ -6,6 +6,7 @@ using System.IO;
 using BenchmarkDotNet.Attributes;
 
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Tests;
 using SDSize = System.Drawing.Size;
 
@@ -30,25 +31,21 @@ namespace SixLabors.ImageSharp.Benchmarks.Codecs.Jpeg
         [Benchmark(Baseline = true, Description = "System.Drawing FULL")]
         public SDSize JpegSystemDrawing()
         {
-            using (var memoryStream = new MemoryStream(this.jpegBytes))
+            using var memoryStream = new MemoryStream(this.jpegBytes);
-            {
+            using var image = System.Drawing.Image.FromStream(memoryStream);
-                using (var image = System.Drawing.Image.FromStream(memoryStream))
-                {
             return image.Size;
         }
-            }
-        }
 
         [Benchmark(Description = "JpegDecoderCore.ParseStream")]
         public void ParseStreamPdfJs()
         {
-            using (var memoryStream = new MemoryStream(this.jpegBytes))
+            using var memoryStream = new MemoryStream(this.jpegBytes);
-            {
+            using var bufferedStream = new BufferedReadStream(memoryStream);
-                var decoder = new JpegDecoderCore(Configuration.Default, new Formats.Jpeg.JpegDecoder { IgnoreMetadata = true });
+
-                decoder.ParseStream(memoryStream);
+            var decoder = new JpegDecoderCore(Configuration.Default, new JpegDecoder { IgnoreMetadata = true });
+            decoder.ParseStream(bufferedStream);
             decoder.Dispose();
         }
-        }
 
         // RESULTS (2019 April 23):
         //

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

@@ -6,6 +6,7 @@ using System.IO;
 using System.Linq;
 using Microsoft.DotNet.RemoteExecutor;
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.Formats.Jpg.Utils;
@@ -71,17 +72,16 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
         public void ParseStream_BasicPropertiesAreCorrect()
         {
             byte[] bytes = TestFile.Create(TestImages.Jpeg.Progressive.Progress).Bytes;
-            using (var ms = new MemoryStream(bytes))
+            using var ms = new MemoryStream(bytes);
-            {
+            using var bufferedStream = new BufferedReadStream(ms);
             var decoder = new JpegDecoderCore(Configuration.Default, new JpegDecoder());
-                decoder.ParseStream(ms);
+            decoder.ParseStream(bufferedStream);
 
             // I don't know why these numbers are different. All I know is that the decoder works
             // and spectral data is exactly correct also.
             // VerifyJpeg.VerifyComponentSizes3(decoder.Frame.Components, 43, 61, 22, 31, 22, 31);
             VerifyJpeg.VerifyComponentSizes3(decoder.Frame.Components, 44, 62, 22, 31, 22, 31);
         }
-        }
 
         public const string DecodeBaselineJpegOutputName = "DecodeBaselineJpeg";
 

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

@@ -6,6 +6,7 @@ using System.IO;
 using System.Linq;
 
 using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Tests.Formats.Jpg.Utils;
@@ -51,14 +52,13 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
 
             byte[] sourceBytes = TestFile.Create(provider.SourceFileOrDescription).Bytes;
 
-            using (var ms = new MemoryStream(sourceBytes))
+            using var ms = new MemoryStream(sourceBytes);
-            {
+            using var bufferedStream = new BufferedReadStream(ms);
-                decoder.ParseStream(ms);
+            decoder.ParseStream(bufferedStream);
 
             var data = LibJpegTools.SpectralData.LoadFromImageSharpDecoder(decoder);
             VerifyJpeg.SaveSpectralImage(provider, data);
         }
-        }
 
         [Theory]
         [WithFileCollection(nameof(AllTestJpegs), PixelTypes.Rgba32)]
@@ -74,14 +74,13 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
 
             byte[] sourceBytes = TestFile.Create(provider.SourceFileOrDescription).Bytes;
 
-            using (var ms = new MemoryStream(sourceBytes))
+            using var ms = new MemoryStream(sourceBytes);
-            {
+            using var bufferedStream = new BufferedReadStream(ms);
-                decoder.ParseStream(ms);
+            decoder.ParseStream(bufferedStream);
-                var imageSharpData = LibJpegTools.SpectralData.LoadFromImageSharpDecoder(decoder);
 
+            var imageSharpData = LibJpegTools.SpectralData.LoadFromImageSharpDecoder(decoder);
             this.VerifySpectralCorrectnessImpl(provider, imageSharpData);
         }
-        }
 
         private void VerifySpectralCorrectnessImpl<TPixel>(
             TestImageProvider<TPixel> provider,

tests/ImageSharp.Tests/Formats/Jpg/Utils/JpegFixture.cs

@@ -8,7 +8,7 @@ using System.Text;
 
 using SixLabors.ImageSharp.Formats.Jpeg;
 using SixLabors.ImageSharp.Formats.Jpeg.Components;
-
+using SixLabors.ImageSharp.IO;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -192,12 +192,13 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg.Utils
         internal static JpegDecoderCore ParseJpegStream(string testFileName, bool metaDataOnly = false)
         {
             byte[] bytes = TestFile.Create(testFileName).Bytes;
-            using (var ms = new MemoryStream(bytes))
+            using var ms = new MemoryStream(bytes);
-            {
+            using var bufferedStream = new BufferedReadStream(ms);
+
             var decoder = new JpegDecoderCore(Configuration.Default, new JpegDecoder());
-                decoder.ParseStream(ms, metaDataOnly);
+            decoder.ParseStream(bufferedStream, metaDataOnly);
+
             return decoder;
         }
     }
 }
-}

tests/ImageSharp.Tests/IO/BufferedReadStreamTests.cs

@@ -143,6 +143,42 @@ namespace SixLabors.ImageSharp.Tests.IO
             }
         }
 
+        [Fact]
+        public void BufferedStreamCanReadSubsequentMultipleByteSpanCorrectly()
+        {
+            using (MemoryStream stream = this.CreateTestStream())
+            {
+                Span<byte> buffer = new byte[2];
+                byte[] expected = stream.ToArray();
+                using (var reader = new BufferedReadStream(stream))
+                {
+                    for (int i = 0, o = 0; i < expected.Length / 2; i++, o += 2)
+                    {
+                        Assert.Equal(2, reader.Read(buffer, 0, 2));
+                        Assert.Equal(expected[o], buffer[0]);
+                        Assert.Equal(expected[o + 1], buffer[1]);
+                        Assert.Equal(o + 2, reader.Position);
+
+                        int offset = i * 2;
+                        if (offset < BufferedReadStream.BufferLength)
+                        {
+                            Assert.Equal(stream.Position, BufferedReadStream.BufferLength);
+                        }
+                        else if (offset >= BufferedReadStream.BufferLength && offset < BufferedReadStream.BufferLength * 2)
+                        {
+                            // We should have advanced to the second chunk now.
+                            Assert.Equal(stream.Position, BufferedReadStream.BufferLength * 2);
+                        }
+                        else
+                        {
+                            // We should have advanced to the third chunk now.
+                            Assert.Equal(stream.Position, BufferedReadStream.BufferLength * 3);
+                        }
+                    }
+                }
+            }
+        }
+
         [Fact]
         public void BufferedStreamCanSkip()
         {

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

@@ -2,10 +2,8 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.IO;
+
-using Moq;
 using SixLabors.ImageSharp.Formats;
-using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
 
 using Xunit;
@@ -44,11 +42,7 @@ namespace SixLabors.ImageSharp.Tests
                 var img = Image.Load<Rgba32>(this.TopLevelConfiguration, this.MockFilePath, this.localDecoder.Object);
 
                 Assert.NotNull(img);
-                this.localDecoder
+                this.localDecoder.Verify(x => x.Decode<Rgba32>(this.TopLevelConfiguration, this.DataStream));
-                    .Verify(
-                    x => x.Decode<Rgba32>(
-                        this.TopLevelConfiguration,
-                        It.Is<Stream>(x => ((BufferedReadStream)x).BaseStream == this.DataStream)));
             }
 
             [Fact]
@@ -57,10 +51,7 @@ namespace SixLabors.ImageSharp.Tests
                 var img = Image.Load(this.TopLevelConfiguration, this.MockFilePath, this.localDecoder.Object);
 
                 Assert.NotNull(img);
-                this.localDecoder.Verify(
+                this.localDecoder.Verify(x => x.Decode(this.TopLevelConfiguration, this.DataStream));
-                    x => x.Decode(
-                        this.TopLevelConfiguration,
-                        It.Is<Stream>(x => ((BufferedReadStream)x).BaseStream == this.DataStream)));
             }
 
             [Fact]

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

@@ -2,9 +2,8 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.IO;
-using Moq;
+
 using SixLabors.ImageSharp.Formats;
-using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.PixelFormats;
 
 using Xunit;
@@ -55,10 +54,7 @@ namespace SixLabors.ImageSharp.Tests
                 var img = Image.Load<Rgba32>(this.TopLevelConfiguration, stream, this.localDecoder.Object);
 
                 Assert.NotNull(img);
-                this.localDecoder.Verify(
+                this.localDecoder.Verify(x => x.Decode<Rgba32>(this.TopLevelConfiguration, stream));
-                    x => x.Decode<Rgba32>(
-                        this.TopLevelConfiguration,
-                        It.Is<Stream>(x => ((BufferedReadStream)x).BaseStream == stream)));
             }
 
             [Fact]
@@ -68,10 +64,7 @@ namespace SixLabors.ImageSharp.Tests
                 var img = Image.Load(this.TopLevelConfiguration, stream, this.localDecoder.Object);
 
                 Assert.NotNull(img);
-                this.localDecoder.Verify(
+                this.localDecoder.Verify(x => x.Decode(this.TopLevelConfiguration, stream));
-                    x => x.Decode(
-                        this.TopLevelConfiguration,
-                        It.Is<Stream>(x => ((BufferedReadStream)x).BaseStream == stream)));
             }
 
             [Fact]