Buffered Decoding.

src/ImageSharp/Common/Extensions/StreamExtensions.cs

@@ -2,11 +2,9 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Buffers;
 using System.IO;
 using SixLabors.ImageSharp.Memory;
-#if !SUPPORTS_SPAN_STREAM
-using System.Buffers;
-#endif
 
 namespace SixLabors.ImageSharp
 {
@@ -40,7 +38,7 @@ public static int Read(this Stream stream, Span<byte> buffer, int offset, int co
         /// Skips the number of bytes in the given stream.
         /// </summary>
         /// <param name="stream">The stream.</param>
-        /// <param name="count">The count.</param>
+        /// <param name="count">A byte offset relative to the origin parameter.</param>
         public static void Skip(this Stream stream, int count)
         {
             if (count < 1)
@@ -51,21 +49,22 @@ public static void Skip(this Stream stream, int count)
             if (stream.CanSeek)
             {
                 stream.Seek(count, SeekOrigin.Current); // Position += count;
+                return;
             }
-            else
+
+            var buffer = ArrayPool<byte>.Shared.Rent(count);
+            while (count > 0)
             {
-                var foo = new byte[count];
-                while (count > 0)
+                int bytesRead = stream.Read(buffer, 0, count);
+                if (bytesRead == 0)
                 {
-                    int bytesRead = stream.Read(foo, 0, count);
-                    if (bytesRead == 0)
-                    {
-                        break;
-                    }
-
-                    count -= bytesRead;
+                    break;
                 }
+
+                count -= bytesRead;
             }
+
+            ArrayPool<byte>.Shared.Return(buffer);
         }
 
         public static void Read(this Stream stream, IManagedByteBuffer buffer)

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 DoubleBufferedStreamReader stream;
+        private readonly Stream stream;
 
         // The entropy encoded code buffer.
         private ulong data;
@@ -22,7 +22,7 @@ internal struct HuffmanScanBuffer
         // Whether there is no more good data to pull from the stream for the current mcu.
         private bool badData;
 
-        public HuffmanScanBuffer(DoubleBufferedStreamReader stream)
+        public HuffmanScanBuffer(Stream stream)
         {
             this.stream = stream;
             this.data = 0ul;

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

@@ -2,10 +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;
-using SixLabors.ImageSharp.Memory;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
 {
@@ -19,7 +18,7 @@ internal class HuffmanScanDecoder
         private readonly JpegFrame frame;
         private readonly HuffmanTable[] dcHuffmanTables;
         private readonly HuffmanTable[] acHuffmanTables;
-        private readonly DoubleBufferedStreamReader stream;
+        private readonly Stream stream;
         private readonly JpegComponent[] components;
 
         // The restart interval.
@@ -65,7 +64,7 @@ internal class HuffmanScanDecoder
         /// <param name="successiveHigh">The successive approximation bit high end.</param>
         /// <param name="successiveLow">The successive approximation bit low end.</param>
         public HuffmanScanDecoder(
-            DoubleBufferedStreamReader stream,
+            Stream stream,
             JpegFrame frame,
             HuffmanTable[] dcHuffmanTables,
             HuffmanTable[] acHuffmanTables,