Opentk/Source/OpenTK/BlittableValueType.cs

98 lines
3.9 KiB
C#

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