Tidying up file detection

Former-commit-id: d8bb807d08a118f2ba387eae4d75bb9959b9b6f3

src/ImageProcessor/Imaging/Formats/BitmapFormat.cs

@@ -21,11 +21,11 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public override byte[][] FileHeaders
+        public override byte[] FileHeader
         {
             get
             {
-                return new[] { Encoding.ASCII.GetBytes("BM") };
+                return Encoding.ASCII.GetBytes("BM");
             }
         }
 

src/ImageProcessor/Imaging/Formats/FormatBase.cs

@@ -23,7 +23,7 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public abstract byte[][] FileHeaders { get; }
+        public abstract byte[] FileHeader { get; }
 
         /// <summary>
         /// Gets the list of file extensions.

src/ImageProcessor/Imaging/Formats/FormatUtilities.cs

@@ -43,15 +43,11 @@ namespace ImageProcessor.Imaging.Formats
             // ReSharper disable once LoopCanBeConvertedToQuery
             foreach (ISupportedImageFormat supportedImageFormat in supportedImageFormats)
             {
-                byte[][] headers = supportedImageFormat.FileHeaders;
-
-                foreach (byte[] header in headers)
+                byte[] header = supportedImageFormat.FileHeader;
+                if (header.SequenceEqual(buffer.Take(header.Length)))
                 {
-                    if (header.SequenceEqual(buffer.Take(header.Length)))
-                    {
-                        stream.Position = 0;
-                        return supportedImageFormat;
-                    }
+                    stream.Position = 0;
+                    return supportedImageFormat;
                 }
             }
 

src/ImageProcessor/Imaging/Formats/GifFormat.cs

@@ -25,11 +25,11 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public override byte[][] FileHeaders
+        public override byte[] FileHeader
         {
             get
             {
-                return new[] { Encoding.ASCII.GetBytes("GIF") };
+                return Encoding.ASCII.GetBytes("GIF");
             }
         }
 

src/ImageProcessor/Imaging/Formats/ISupportedImageFormat.cs

@@ -23,7 +23,7 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        byte[][] FileHeaders { get; }
+        byte[] FileHeader { get; }
 
         /// <summary>
         /// Gets the list of file extensions.

src/ImageProcessor/Imaging/Formats/JpegFormat.cs

@@ -25,18 +25,11 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public override byte[][] FileHeaders
+        public override byte[] FileHeader
         {
             get
             {
-                return new[]
-                           {
-                               new byte[] { 255, 216, 255, 232 },
-                               new byte[] { 255, 216, 255, 227 },
-                               new byte[] { 255, 216, 255, 226 },
-                               new byte[] { 255, 216, 255, 224 },
-                               new byte[] { 255, 216, 255, 225 }
-                           };
+                return new byte[] { 255, 216, 255 };
             }
         }
 

src/ImageProcessor/Imaging/Formats/PngFormat.cs

@@ -22,11 +22,11 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public override byte[][] FileHeaders
+        public override byte[] FileHeader
         {
             get
             {
-                return new[] { new byte[] { 137, 80, 78, 71 } };
+                return new byte[] { 137, 80, 78, 71 };
             }
         }
 

src/ImageProcessor/Imaging/Formats/TiffFormat.cs

@@ -23,11 +23,11 @@ namespace ImageProcessor.Imaging.Formats
         /// <summary>
         /// Gets the file header.
         /// </summary>
-        public override byte[][] FileHeaders
+        public override byte[] FileHeader
         {
             get
             {
-                return new[] { new byte[] { 77, 77, 42 } };
+                return new byte[] { 77, 77, 42 };
             }
         }