Opentk/Source/OpenTK/BlittableValueType.cs

291 lines
10 KiB
C#

#region License
//
// The Open Toolkit Library License
//
// Copyright (c) 2006 - 2010 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
{
#region BlittableValueType<T>
/// <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>
public static class BlittableValueType<T>
{
#region Fields
static readonly Type Type;
static readonly int stride;
#endregion
#region Constructors
static BlittableValueType()
{
Type = typeof(T);
if (Type.IsValueType && !Type.IsGenericType)
{
// Does this support generic types? On Mono 2.4.3 it does
// On .Net it doesn't.
// http://msdn.microsoft.com/en-us/library/5s4920fa.aspx
stride = Marshal.SizeOf(typeof(T));
}
}
#endregion
#region Public Members
/// <summary>
/// Gets the size of the type in bytes or 0 for non-blittable types.
/// </summary>
/// <remarks>
/// This property returns 0 for non-blittable types.
/// </remarks>
public static int Stride { get { return stride; } }
#region Check
/// <summary>
/// Checks whether the current typename T is blittable.
/// </summary>
/// <returns>True if T is blittable; false otherwise.</returns>
public static bool Check()
{
return Check(Type);
}
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">A System.Type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
public static bool Check(Type type)
{
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);
return CheckType(type);
}
#endregion
#endregion
#region Private Members
// 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;
if (!type.IsValueType)
return false;
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 Stride != 0;
}
// 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;
}
#endregion
}
#endregion
#region BlittableValueType
/// <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>
public static class BlittableValueType
{
#region Check
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">An instance of the type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
public static bool Check<T>(T type)
{
return BlittableValueType<T>.Check();
}
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">An instance of the type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
[CLSCompliant(false)]
public static bool Check<T>(T[] type)
{
return BlittableValueType<T>.Check();
}
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">An instance of the type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
[CLSCompliant(false)]
public static bool Check<T>(T[,] type)
{
return BlittableValueType<T>.Check();
}
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">An instance of the type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
[CLSCompliant(false)]
public static bool Check<T>(T[, ,] type)
{
return BlittableValueType<T>.Check();
}
/// <summary>
/// Checks whether type is a blittable value type.
/// </summary>
/// <param name="type">An instance of the type to check.</param>
/// <returns>True if T is blittable; false otherwise.</returns>
[CLSCompliant(false)]
public static bool Check<T>(T[][] type)
{
return BlittableValueType<T>.Check();
}
#endregion
#region StrideOf
/// <summary>
/// Returns the size of the specified value type in bytes or 0 if the type is not blittable.
/// </summary>
/// <typeparam name="T">The value type. Must be blittable.</typeparam>
/// <param name="type">An instance of the value type.</param>
/// <returns>An integer, specifying the size of the type in bytes.</returns>
/// <exception cref="System.ArgumentException">Occurs when type is not blittable.</exception>
public static int StrideOf<T>(T type)
{
if (!Check(type))
throw new ArgumentException("type");
return BlittableValueType<T>.Stride;
}
/// <summary>
/// Returns the size of a single array element in bytes or 0 if the element is not blittable.
/// </summary>
/// <typeparam name="T">The value type.</typeparam>
/// <param name="type">An instance of the value type.</param>
/// <returns>An integer, specifying the size of the type in bytes.</returns>
/// <exception cref="System.ArgumentException">Occurs when type is not blittable.</exception>
[CLSCompliant(false)]
public static int StrideOf<T>(T[] type)
{
if (!Check(type))
throw new ArgumentException("type");
return BlittableValueType<T>.Stride;
}
/// <summary>
/// Returns the size of a single array element in bytes or 0 if the element is not blittable.
/// </summary>
/// <typeparam name="T">The value type.</typeparam>
/// <param name="type">An instance of the value type.</param>
/// <returns>An integer, specifying the size of the type in bytes.</returns>
/// <exception cref="System.ArgumentException">Occurs when type is not blittable.</exception>
[CLSCompliant(false)]
public static int StrideOf<T>(T[,] type)
{
if (!Check(type))
throw new ArgumentException("type");
return BlittableValueType<T>.Stride;
}
/// <summary>
/// Returns the size of a single array element in bytes or 0 if the element is not blittable.
/// </summary>
/// <typeparam name="T">The value type.</typeparam>
/// <param name="type">An instance of the value type.</param>
/// <returns>An integer, specifying the size of the type in bytes.</returns>
/// <exception cref="System.ArgumentException">Occurs when type is not blittable.</exception>
[CLSCompliant(false)]
public static int StrideOf<T>(T[, ,] type)
{
if (!Check(type))
throw new ArgumentException("type");
return BlittableValueType<T>.Stride;
}
#endregion
}
#endregion
}