[Bind][ES][GL] Output entry points as byte[]

Moving from string[] to byte[] reduces startup memory allocations
tremendously (up to 70% lower memory use on Windows!)

Source/Bind/CSharpSpecWriter.cs

@@ -168,19 +168,42 @@ namespace Bind
             sw.WriteLine("static {0}()", Settings.OutputClass);
             sw.WriteLine("{");
             sw.Indent();
-            sw.WriteLine("EntryPointNames = new string[]", delegates.Count);
+            // Write entry point names.
+            // Instead of strings, which are costly to construct,
+            // we use a 1d array of ASCII bytes. Names are laid out
+            // sequentially, with a nul-terminator between them.
+            sw.WriteLine("EntryPointNames = new byte[]", delegates.Count);
             sw.WriteLine("{");
             sw.Indent();
             foreach (var d in delegates.Values.Select(d => d.First()))
             {
                 if (d.RequiresSlot(Settings))
                 {
-                    sw.WriteLine("\"{0}{1}\",", Settings.FunctionPrefix, d.Name);
+                    var name = Settings.FunctionPrefix + d.Name;
+                    sw.WriteLine("{0}, 0,", String.Join(", ",
+                        System.Text.Encoding.ASCII.GetBytes(name).Select(b => b.ToString()).ToArray()));
                 }
             }
             sw.Unindent();
             sw.WriteLine("};");
-            sw.WriteLine("EntryPoints = new IntPtr[EntryPointNames.Length];");
+            // Write entry point name offsets.
+            // This is an array of offsets into the EntryPointNames[] array above.
+            sw.WriteLine("EntryPointNameOffsets = new int[]", delegates.Count);
+            sw.WriteLine("{");
+            sw.Indent();
+            int offset = 0;
+            foreach (var d in delegates.Values.Select(d => d.First()))
+            {
+                if (d.RequiresSlot(Settings))
+                {
+                    sw.WriteLine("{0},", offset);
+                    var name = Settings.FunctionPrefix + d.Name;
+                    offset += name.Length + 1;
+                }
+            }
+            sw.Unindent();
+            sw.WriteLine("};");
+            sw.WriteLine("EntryPoints = new IntPtr[EntryPointNameOffsets.Length];");
             sw.Unindent();
             sw.WriteLine("}");
             sw.WriteLine();

Source/OpenTK/Graphics/ES11/Helper.cs

@@ -16,7 +16,8 @@ namespace OpenTK.Graphics.ES11
         static readonly object sync_root = new object();
 
         static IntPtr[] EntryPoints;
-        static string[] EntryPointNames;
+        static byte[] EntryPointNames;
+        static int[] EntryPointNameOffsets;
 
         #region Constructors
 
@@ -27,6 +28,7 @@ namespace OpenTK.Graphics.ES11
         {
             EntryPointsInstance = EntryPoints;
             EntryPointNamesInstance = EntryPointNames;
+            EntryPointNameOffsetsInstance = EntryPointNameOffsets;
         }
 
         #endregion

Source/OpenTK/Graphics/ES20/Helper.cs

@@ -44,7 +44,8 @@ namespace OpenTK.Graphics.ES20
         static readonly object sync_root = new object();
 
         static IntPtr[] EntryPoints;
-        static string[] EntryPointNames;
+        static byte[] EntryPointNames;
+        static int[] EntryPointNameOffsets;
 
         #region Constructors
 
@@ -55,6 +56,7 @@ namespace OpenTK.Graphics.ES20
         {
             EntryPointsInstance = EntryPoints;
             EntryPointNamesInstance = EntryPointNames;
+            EntryPointNameOffsetsInstance = EntryPointNameOffsets;
         }
 
         #endregion

Source/OpenTK/Graphics/ES30/Helper.cs

@@ -44,7 +44,8 @@ namespace OpenTK.Graphics.ES30
         static readonly object sync_root = new object();
 
         static IntPtr[] EntryPoints;
-        static string[] EntryPointNames;
+        static byte[] EntryPointNames;
+        static int[] EntryPointNameOffsets;
 
         #region Constructors
 
@@ -55,6 +56,7 @@ namespace OpenTK.Graphics.ES30
         {
             EntryPointsInstance = EntryPoints;
             EntryPointNamesInstance = EntryPointNames;
+            EntryPointNameOffsetsInstance = EntryPointNameOffsets;
         }
 
         #endregion

Source/OpenTK/Graphics/GraphicsBindingsBase.cs

@@ -45,7 +45,9 @@ namespace OpenTK.Graphics
         /// Contains the list of API entry point names.
         /// This field must be set by an inheriting class.
         /// </summary>
-        protected string[] EntryPointNamesInstance;
+        protected byte[] EntryPointNamesInstance;
+
+        protected int[] EntryPointNameOffsetsInstance;
 
         /// <summary>
         /// Retrieves an unmanaged function pointer to the specified function.
@@ -81,9 +83,16 @@ namespace OpenTK.Graphics
                 throw new GraphicsContextMissingException();
 
             IGraphicsContextInternal context_internal = context as IGraphicsContextInternal;
-            for (int i = 0; i < EntryPointsInstance.Length; i++)
+            unsafe
             {
-                EntryPointsInstance[i] = context_internal.GetAddress(EntryPointNamesInstance[i]);
+                fixed (byte* name = EntryPointNamesInstance)
+                {
+                    for (int i = 0; i < EntryPointsInstance.Length; i++)
+                    {
+                        EntryPointsInstance[i] = context_internal.GetAddress(
+                            new IntPtr(name + EntryPointNameOffsetsInstance[i]));
+                    }
+                }
             }
         }
     }

Source/OpenTK/Graphics/OpenGL/GLHelper.cs

@@ -79,7 +79,8 @@ namespace OpenTK.Graphics.OpenGL
         static readonly object sync_root = new object();
 
         static IntPtr[] EntryPoints;
-        static string[] EntryPointNames;
+        static byte[] EntryPointNames;
+        static int[] EntryPointNameOffsets;
 
         #endregion
 
@@ -92,6 +93,7 @@ namespace OpenTK.Graphics.OpenGL
         {
             EntryPointsInstance = EntryPoints;
             EntryPointNamesInstance = EntryPointNames;
+            EntryPointNameOffsetsInstance = EntryPointNameOffsets;
         }
 
         #endregion

Source/OpenTK/Graphics/OpenGL4/Helper.cs

@@ -44,7 +44,8 @@ namespace OpenTK.Graphics.OpenGL4
         static readonly object sync_root = new object();
 
         static IntPtr[] EntryPoints;
-        static string[] EntryPointNames;
+        static byte[] EntryPointNames;
+        static int[] EntryPointNameOffsets;
 
         #region Constructors
 
@@ -55,6 +56,7 @@ namespace OpenTK.Graphics.OpenGL4
         {
             EntryPointsInstance = EntryPoints;
             EntryPointNamesInstance = EntryPointNames;
+            EntryPointNameOffsetsInstance = EntryPointNameOffsets;
         }
 
         #endregion