Added BlittableValueType struct that can be used to check whether any given value type is blittable.
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Source/OpenTK/BlittableValueType.cs
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Source/OpenTK/BlittableValueType.cs
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#region License
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//
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// The Open Toolkit Library License
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//
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// Copyright (c) 2006 - 2009 the Open Toolkit library.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights to
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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// the Software, and to permit persons to whom the Software is furnished to do
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// so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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// OTHER DEALINGS IN THE SOFTWARE.
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//
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#endregion
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using System;
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using System.Collections.Generic;
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using System.Text;
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using System.Runtime.InteropServices;
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using System.Diagnostics;
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using System.Reflection;
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namespace OpenTK
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{
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/// <summary>
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/// Checks whether the specified type parameter is a blittable value type.
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/// </summary>
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/// <remarks>
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/// A blittable value type is a struct that only references other value types recursively,
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/// which allows it to be passed to unmanaged code directly.
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/// </remarks>
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/// <typeparam name="T">The struct to check.</typeparam>
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/// <exception cref="System.NotSupportedException">Raised when T is not a blittable value type.</exception>
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public struct BlittableValueType<T> where T : struct
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{
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/// <summary>
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/// Gets the size of the type in bytes.
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/// </summary>
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public static readonly int Stride = Marshal.SizeOf(typeof(T));
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static BlittableValueType()
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{
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Type type = typeof(T);
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if (!CheckStructLayoutAttribute(type))
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Debug.Print("Warning: type {0} does not specify a StructLayoutAttribute with Pack=1. The memory layout of the struct may change between platforms.", type.Name);
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if (!CheckType(type))
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throw new NotSupportedException(String.Format("Type {0} contains non-primitive fields.", type.Name));
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}
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// Checks whether the parameter is a primitive type or consists of primitive types recursively.
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// Throws a NotSupportedException if it is not.
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static bool CheckType(Type type)
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{
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//Debug.Print("Checking type {0} (size: {1} bytes).", type.Name, Marshal.SizeOf(type));
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if (type.IsPrimitive)
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return true;
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FieldInfo[] fields = type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
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Debug.Indent();
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foreach (FieldInfo field in fields)
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{
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if (!CheckType(field.FieldType))
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return false;
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}
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Debug.Unindent();
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return true;
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}
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// Checks whether the specified struct defines [StructLayout(LayoutKind.Sequential, Pack=1)]
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// or [StructLayout(LayoutKind.Explicit)]
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static bool CheckStructLayoutAttribute(Type type)
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{
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StructLayoutAttribute[] attr = (StructLayoutAttribute[])
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type.GetCustomAttributes(typeof(StructLayoutAttribute), true);
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if ((attr == null) ||
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(attr != null && attr.Length > 0 && attr[0].Value != LayoutKind.Explicit && attr[0].Pack != 1))
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return false;
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return true;
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}
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}
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}
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