better EOF handling logic

src/ImageSharp/Formats/Jpeg/GolangPort/Components/Decoder/DecoderThrowHelper.cs

@@ -18,20 +18,17 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort.Components.Decoder
         [MethodImpl(MethodImplOptions.NoInlining)]
         public static void ThrowExceptionForErrorCode(this OrigDecoderErrorCode errorCode)
         {
+            // REMARK: If this method throws for an image that is expected to be decodable,
+            // consider using the ***Unsafe variant of the parsing method that asks for ThrowExceptionForErrorCode()
+            // then verify the error code + implement fallback logic manually!
             switch (errorCode)
             {
                 case OrigDecoderErrorCode.NoError:
                     throw new ArgumentException("ThrowExceptionForErrorCode() called with NoError!", nameof(errorCode));
                 case OrigDecoderErrorCode.MissingFF00:
                     throw new MissingFF00Exception();
-
                 case OrigDecoderErrorCode.UnexpectedEndOfStream:
-
-                    // TODO:
-                    // Disabled for now since we want to avoid throwing for most bad eof.
-                    // Will probably delete
-                    // throw new EOFException();
-                    break;
+                    throw new EOFException();
                 default:
                     throw new ArgumentOutOfRangeException(nameof(errorCode), errorCode, null);
             }

src/ImageSharp/Formats/Jpeg/GolangPort/Components/Decoder/InputProcessor.cs

@@ -107,6 +107,13 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort.Components.Decoder
             return this.Bytes.ReadByte(this.InputStream);
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public OrigDecoderErrorCode ReadByteUnsafe(out byte result)
+        {
+            this.LastErrorCode = this.Bytes.ReadByteUnsafe(this.InputStream, out result);
+            return this.LastErrorCode;
+        }
+
         /// <summary>
         /// Decodes a single bit
         /// TODO: This method (and also the usages) could be optimized by batching!

src/ImageSharp/Formats/Jpeg/GolangPort/OrigJpegDecoderCore.cs

@@ -289,7 +289,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
                 {
                     // Section B.1.1.2 says, "Any marker may optionally be preceded by any
                     // number of fill bytes, which are bytes assigned code X'FF'".
-                    marker = this.InputProcessor.ReadByte();
+                    this.InputProcessor.ReadByteUnsafe(out marker);
 
                     if (this.InputProcessor.ReachedEOF)
                     {
@@ -318,7 +318,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.GolangPort
 
                 // Read the 16-bit length of the segment. The value includes the 2 bytes for the
                 // length itself, so we subtract 2 to get the number of remaining bytes.
-                this.InputProcessor.ReadFull(this.Temp, 0, 2);
+                this.InputProcessor.ReadFullUnsafe(this.Temp, 0, 2);
                 int remaining = (this.Temp[0] << 8) + this.Temp[1] - 2;
                 if (remaining < 0)
                 {