jankily reimplement gif parser using gwaredd/mgGif

MelonStartScreen/EnumExtensions.cs

@@ -0,0 +1,30 @@
+using System;
+
+namespace MelonLoader.MelonStartScreen
+{
+    /// <summary>
+    /// Extentions for enums.
+    /// </summary>
+    public static class EnumExtensions
+    {
+        /// <summary>
+        /// A FX 3.5 way to mimic the FX4 "HasFlag" method.
+        /// </summary>
+        /// <param name="variable">The tested enum.</param>
+        /// <param name="value">The value to test.</param>
+        /// <returns>True if the flag is set. Otherwise false.</returns>
+        public static bool HasFlag(this Enum variable, Enum value)
+        {
+            // check if from the same type.
+            if (variable.GetType() != value.GetType())
+            {
+                throw new ArgumentException("The checked flag is not from the same type as the checked variable.");
+            }
+
+            ulong num = Convert.ToUInt64(value);
+            ulong num2 = Convert.ToUInt64(variable);
+
+            return (num2 & num) == num;
+        }
+    }
+}