// Copyright (c) Xenko contributors (https://xenko.com) and Silicon Studio Corp. (https://www.siliconstudio.co.jp)
// Distributed under the MIT license. See the LICENSE.md file in the project root for more information.
//
// Copyright (c) 2010-2012 SharpDX - Alexandre Mutel
// 
// 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.
#pragma warning disable SA1405 // Debug.Assert must provide message text
using att;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;
using System.Threading;

namespace lib
{
    /// <summary>
    /// Utility class.
    /// </summary>
    public static class Util
    {

		/*
		#if XENKO_PLATFORM_UWP
						public static unsafe void CopyMemory(IntPtr dest, IntPtr src, int sizeInBytesToCopy)
						{
								Interop.memcpy((void*)dest, (void*)src, sizeInBytesToCopy);
						}
		#else
		#if XENKO_PLATFORM_WINDOWS_DESKTOP
						private const string MemcpyDll = "msvcrt.dll";
		#elif XENKO_PLATFORM_ANDROID
						private const string MemcpyDll = "libc.so";
		#elif XENKO_PLATFORM_UNIX
						// We do not specifiy the .so extension as libc.so on Linux
						// is actually not a .so files but a script. Using just libc
						// will automatically find the corresponding .so.
						private const string MemcpyDll = "libc";
		#elif XENKO_PLATFORM_IOS
						private const string MemcpyDll = ObjCRuntime.Constants.SystemLibrary;
		#else
		#   error Unsupported platform
		#endif
						[DllImport(MemcpyDll, EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]
		#if !XENKO_RUNTIME_CORECLR
						[SuppressUnmanagedCodeSecurity]
		#endif
						private static extern IntPtr CopyMemory(IntPtr dest, IntPtr src, ulong sizeInBytesToCopy);

						/// <summary>
						/// Copy memory.
						/// </summary>
						/// <param name="dest">The destination memory location</param>
						/// <param name="src">The source memory location.</param>
						/// <param name="sizeInBytesToCopy">The count.</param>
						public static void CopyMemory(IntPtr dest, IntPtr src, int sizeInBytesToCopy)
						{
								CopyMemory(dest, src, (ulong)sizeInBytesToCopy);
						}
		#endif
		*/



		public static void checkAndAddDirectory( string path )
		{
			if( !Directory.Exists( path ) )
			{
				lib.Log.info( "Creating directory {0}", path );
				Directory.CreateDirectory( path );
			}

		}


		/// <summary>
		/// Compares two block of memory.
		/// </summary>
		/// <param name="from">The pointer to compare from.</param>
		/// <param name="against">The pointer to compare against.</param>
		/// <param name="sizeToCompare">The size in bytes to compare.</param>
		/// <returns>True if the buffers are equivalent, false otherwise.</returns>
		public static unsafe bool CompareMemory(IntPtr from, IntPtr against, int sizeToCompare)
        {
            var pSrc = (byte*)from;
            var pDst = (byte*)against;

            // Compare 8 bytes.
            var numberOf = sizeToCompare >> 3;
            while (numberOf > 0)
            {
                if (*(long*)pSrc != *(long*)pDst)
                    return false;
                pSrc += 8;
                pDst += 8;
                numberOf--;
            }

            // Compare remaining bytes.
            numberOf = sizeToCompare & 7;
            while (numberOf > 0)
            {
                if (*pSrc != *pDst)
                    return false;
                pSrc++;
                pDst++;
                numberOf--;
            }

            return true;
        }

        /// <summary>
        /// Clears the memory.
        /// </summary>
        /// <param name="dest">The dest.</param>
        /// <param name="value">The value.</param>
        /// <param name="sizeInBytesToClear">The size in bytes to clear.</param>
        public static void ClearMemory(IntPtr dest, byte value, int sizeInBytesToClear)
        {
            unsafe
            {
                Interop.memset((void*)dest, value, sizeInBytesToClear);
            }
        }

        /// <summary>
        /// Return the sizeof a struct from a CLR. Equivalent to sizeof operator but works on generics too.
        /// </summary>
        /// <typeparam name="T">a struct to evaluate</typeparam>
        /// <returns>sizeof this struct</returns>
        public static int SizeOf<T>() where T : struct
        {
            return Interop.SizeOf<T>();
        }

        /// <summary>
        /// Return the sizeof an array of struct. Equivalent to sizeof operator but works on generics too.
        /// </summary>
        /// <typeparam name="T">a struct</typeparam>
        /// <param name="array">The array of struct to evaluate.</param>
        /// <returns>sizeof in bytes of this array of struct</returns>
        public static int SizeOf<T>(T[] array) where T : struct
        {
            return array == null ? 0 : array.Length * Interop.SizeOf<T>();
        }

        /// <summary>
        /// Pins the specified source and call an action with the pinned pointer.
        /// </summary>
        /// <typeparam name="T">The type of the structure to pin</typeparam>
        /// <param name="source">The source.</param>
        /// <param name="pinAction">The pin action to perform on the pinned pointer.</param>
        public static void Pin<T>(ref T source, Action<IntPtr> pinAction) where T : struct
        {
            unsafe
            {
                pinAction((IntPtr)Interop.Fixed(ref source));
            }
        }

        /// <summary>
        /// Pins the specified source and call an action with the pinned pointer.
        /// </summary>
        /// <typeparam name="T">The type of the structure to pin</typeparam>
        /// <param name="source">The source array.</param>
        /// <param name="pinAction">The pin action to perform on the pinned pointer.</param>
        public static void Pin<T>(T[] source, [NotNull] Action<IntPtr> pinAction) where T : struct
        {
            unsafe
            {
                pinAction(source == null ? IntPtr.Zero : (IntPtr)Interop.Fixed(source));
            }
        }

        /// <summary>
        /// Covnerts a structured array to an equivalent byte array.
        /// </summary>
        /// <param name="source">The source.</param>
        /// <returns>The byte array.</returns>
        public static byte[] ToByteArray<T>(T[] source) where T : struct
        {
            if (source == null) return null;

            var buffer = new byte[SizeOf<T>() * source.Length];

            if (source.Length == 0)
                return buffer;

            unsafe
            {
                fixed (void* pBuffer = buffer)
                    Interop.Write(pBuffer, source, 0, source.Length);
            }
            return buffer;
        }

        /// <summary>
        /// Reads the specified T data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <returns>The data read from the memory location</returns>
        public static T Read<T>(IntPtr source) where T : struct
        {
            unsafe
            {
                return Interop.ReadInline<T>((void*)source);
            }
        }

        /// <summary>
        /// Reads the specified T data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <param name="data">The data write to.</param>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void Read<T>(IntPtr source, ref T data) where T : struct
        {
            unsafe
            {
                Interop.CopyInline(ref data, (void*)source);
            }
        }

        /// <summary>
        /// Reads the specified T data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <param name="data">The data write to.</param>
        public static void ReadOut<T>(IntPtr source, out T data) where T : struct
        {
            unsafe
            {
                Interop.CopyInlineOut(out data, (void*)source);
            }
        }

        /// <summary>
        /// Reads the specified T data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <param name="data">The data write to.</param>
        /// <returns>source pointer + sizeof(T)</returns>
        public static IntPtr ReadAndPosition<T>(IntPtr source, ref T data) where T : struct
        {
            unsafe
            {
                return (IntPtr)Interop.Read((void*)source, ref data);
            }
        }

        /// <summary>
        /// Reads the specified array T[] data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <param name="data">The data write to.</param>
        /// <param name="offset">The offset in the array to write to.</param>
        /// <param name="count">The number of T element to read from the memory location</param>
        /// <returns>source pointer + sizeof(T) * count</returns>
        public static IntPtr Read<T>(IntPtr source, T[] data, int offset, int count) where T : struct
        {
            unsafe
            {
                return (IntPtr)Interop.Read((void*)source, data, offset, count);
            }
        }

        /// <summary>
        /// Writes the specified T data to a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to write</typeparam>
        /// <param name="destination">Memory location to write to.</param>
        /// <param name="data">The data to write.</param>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void Write<T>(IntPtr destination, ref T data) where T : struct
        {
            unsafe
            {
                Interop.CopyInline((void*)destination, ref data);
            }
        }

        /// <summary>
        /// Writes the specified T data to a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to write</typeparam>
        /// <param name="destination">Memory location to write to.</param>
        /// <param name="data">The data to write.</param>
        /// <returns>destination pointer + sizeof(T)</returns>
        public static IntPtr WriteAndPosition<T>(IntPtr destination, ref T data) where T : struct
        {
            unsafe
            {
                return (IntPtr)Interop.Write((void*)destination, ref data);
            }
        }

        /// <summary>
        /// Writes the specified array T[] data to a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to write</typeparam>
        /// <param name="destination">Memory location to write to.</param>
        /// <param name="data">The array of T data to write.</param>
        /// <param name="offset">The offset in the array to read from.</param>
        /// <param name="count">The number of T element to write to the memory location</param>
        public static void Write<T>(byte[] destination, T[] data, int offset, int count) where T : struct
        {
            unsafe
            {
                fixed (void* pDest = destination)
                {
                    Write((IntPtr)pDest, data, offset, count);
                }
            }
        }

        /// <summary>
        /// Writes the specified array T[] data to a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to write</typeparam>
        /// <param name="destination">Memory location to write to.</param>
        /// <param name="data">The array of T data to write.</param>
        /// <param name="offset">The offset in the array to read from.</param>
        /// <param name="count">The number of T element to write to the memory location</param>
        /// <returns>destination pointer + sizeof(T) * count</returns>
        public static IntPtr Write<T>(IntPtr destination, T[] data, int offset, int count) where T : struct
        {
            unsafe
            {
                return (IntPtr)Interop.Write((void*)destination, data, offset, count);
            }
        }

        /// <summary>
        /// Allocate an aligned memory buffer.
        /// </summary>
        /// <param name="sizeInBytes">Size of the buffer to allocate.</param>
        /// <param name="align">Alignment, a positive value which is a power of 2. 16 bytes by default.</param>
        /// <returns>A pointer to a buffer aligned.</returns>
        /// <remarks>
        /// To free this buffer, call <see cref="FreeMemory"/>
        /// </remarks>
        public static unsafe IntPtr AllocateMemory(int sizeInBytes, int align = 16)
        {
            var mask = align - 1;
            if ((align & mask) != 0)
            {
                throw new ArgumentException("Alignment is not power of 2", nameof(align));
            }
            var memPtr = Marshal.AllocHGlobal(sizeInBytes + mask + sizeof(void*));
            var ptr = (byte*)((ulong)(memPtr.ToInt32() + sizeof(void*) + mask) & ~(ulong)mask);
            ((IntPtr*)ptr)[-1] = memPtr;
            return new IntPtr(ptr);
        }

        /// <summary>
        /// Allocate an aligned memory buffer and clear it with a specified value (0 by defaault).
        /// </summary>
        /// <param name="sizeInBytes">Size of the buffer to allocate.</param>
        /// <param name="clearValue">Default value used to clear the buffer.</param>
        /// <param name="align">Alignment, 16 bytes by default.</param>
        /// <returns>A pointer to a buffer aligned.</returns>
        /// <remarks>
        /// To free this buffer, call <see cref="FreeMemory"/>
        /// </remarks>
        public static IntPtr AllocateClearedMemory(int sizeInBytes, byte clearValue = 0, int align = 16)
        {
            var ptr = AllocateMemory(sizeInBytes, align);
            ClearMemory(ptr, clearValue, sizeInBytes);
            return ptr;
        }

        /// <summary>
        /// Determines whether the specified memory pointer is aligned in memory.
        /// </summary>
        /// <param name="memoryPtr">The memory pointer.</param>
        /// <param name="align">The align.</param>
        /// <returns><c>true</c> if the specified memory pointer is aligned in memory; otherwise, <c>false</c>.</returns>
        public static bool IsMemoryAligned(IntPtr memoryPtr, int align = 16)
        {
            return (memoryPtr.ToInt64() & (align - 1)) == 0;
        }

        /// <summary>
        /// Allocate an aligned memory buffer.
        /// </summary>
        /// <remarks>
        /// The buffer must have been allocated with <see cref="AllocateMemory"/>
        /// </remarks>
        public static unsafe void FreeMemory(IntPtr alignedBuffer)
        {
            Marshal.FreeHGlobal(((IntPtr*)alignedBuffer)[-1]);
        }

        /// <summary>
        /// If non-null, disposes the specified object and set it to null, otherwise do nothing.
        /// </summary>
        /// <param name="disposable">The disposable.</param>
        public static void Dispose<T>(ref T disposable) where T : class, IDisposable
        {
            if (disposable != null)
            {
                disposable.Dispose();
                disposable = null;
            }
        }

        /// <summary>
        /// String helper join method to display an array of object as a single string.
        /// </summary>
        /// <param name="separator">The separator.</param>
        /// <param name="array">The array.</param>
        /// <returns>a string with array elements serparated by the seperator</returns>
        [NotNull]
        public static string Join<T>(string separator, T[] array)
        {
            var text = new StringBuilder();
            if (array != null)
            {
                for (var i = 0; i < array.Length; i++)
                {
                    if (i > 0) text.Append(separator);
                    text.Append(array[i]);
                }
            }
            return text.ToString();
        }

        /// <summary>
        /// String helper join method to display an enumrable of object as a single string.
        /// </summary>
        /// <param name="separator">The separator.</param>
        /// <param name="elements">The enumerable.</param>
        /// <returns>a string with array elements serparated by the seperator</returns>
        [NotNull]
        public static string Join(string separator, [NotNull] IEnumerable elements)
        {
            var elementList = new List<string>();
            foreach (var element in elements)
                elementList.Add(element.ToString());

            var text = new StringBuilder();
            for (var i = 0; i < elementList.Count; i++)
            {
                var element = elementList[i];
                if (i > 0) text.Append(separator);
                text.Append(element);
            }
            return text.ToString();
        }

        /// <summary>
        /// String helper join method to display an enumrable of object as a single string.
        /// </summary>
        /// <param name="separator">The separator.</param>
        /// <param name="elements">The enumerable.</param>
        /// <returns>a string with array elements serparated by the seperator</returns>
        [NotNull]
        public static string Join(string separator, [NotNull] IEnumerator elements)
        {
            var elementList = new List<string>();
            while (elements.MoveNext())
                elementList.Add(elements.Current.ToString());

            var text = new StringBuilder();
            for (var i = 0; i < elementList.Count; i++)
            {
                var element = elementList[i];
                if (i > 0) text.Append(separator);
                text.Append(element);
            }
            return text.ToString();
        }

        /// <summary>
        ///   Read stream to a byte[] buffer
        /// </summary>
        /// <param name = "stream">input stream</param>
        /// <returns>a byte[] buffer</returns>
        [NotNull]
        public static byte[] ReadStream([NotNull] Stream stream)
        {
            var readLength = 0;
            return ReadStream(stream, ref readLength);
        }

        /// <summary>
        ///   Read stream to a byte[] buffer
        /// </summary>
        /// <param name = "stream">input stream</param>
        /// <param name = "readLength">length to read</param>
        /// <returns>a byte[] buffer</returns>
        [NotNull]
        public static byte[] ReadStream([NotNull] Stream stream, ref int readLength)
        {
            System.Diagnostics.Debug.Assert(stream != null);
            System.Diagnostics.Debug.Assert(stream.CanRead);
            var num = readLength;
            System.Diagnostics.Debug.Assert(num <= (stream.Length - stream.Position));
            if (num == 0)
                readLength = (int)(stream.Length - stream.Position);
            num = readLength;

            System.Diagnostics.Debug.Assert(num >= 0);
            if (num == 0)
                return new byte[0];

            var buffer = new byte[num];
            var bytesRead = 0;
            if (num > 0)
            {
                do
                {
                    bytesRead += stream.Read(buffer, bytesRead, readLength - bytesRead);
                } while (bytesRead < readLength);
            }
            return buffer;
        }

        /// <summary>
        /// Computes a hashcode for a dictionary.
        /// </summary>
        /// <returns>Hashcode for the list.</returns>
        public static int GetHashCode(IDictionary dict)
        {
            if (dict == null)
                return 0;

            var hashCode = 0;
            foreach (DictionaryEntry keyValue in dict)
            {
                hashCode = (hashCode * 397) ^ keyValue.Key.GetHashCode();
                hashCode = (hashCode * 397) ^ (keyValue.Value?.GetHashCode() ?? 0);
            }
            return hashCode;
        }

        /// <summary>
        /// Computes a hashcode for an enumeration
        /// </summary>
        /// <param name="it">An enumerator.</param>
        /// <returns>Hashcode for the list.</returns>
        public static int GetHashCode(IEnumerable it)
        {
            if (it == null)
                return 0;

            var hashCode = 0;
            foreach (var current in it)
            {
                hashCode = (hashCode * 397) ^ (current?.GetHashCode() ?? 0);
            }
            return hashCode;
        }

        /// <summary>
        /// Computes a hashcode for an enumeration
        /// </summary>
        /// <param name="it">An enumerator.</param>
        /// <returns>Hashcode for the list.</returns>
        public static int GetHashCode(IEnumerator it)
        {
            if (it == null)
                return 0;

            var hashCode = 0;
            while (it.MoveNext())
            {
                var current = it.Current;
                hashCode = (hashCode * 397) ^ (current?.GetHashCode() ?? 0);
            }
            return hashCode;
        }

        /// <summary>
        /// Compares two collection, element by elements.
        /// </summary>
        /// <param name="left">A "from" enumerator.</param>
        /// <param name="right">A "to" enumerator.</param>
        /// <returns>True if lists are identical. False otherwise.</returns>
        public static bool Compare(IEnumerable left, IEnumerable right)
        {
            if (ReferenceEquals(left, right))
                return true;
            if (ReferenceEquals(left, null) || ReferenceEquals(right, null))
                return false;

            return Compare(left.GetEnumerator(), right.GetEnumerator());
        }

        /// <summary>
        /// Compares two collection, element by elements.
        /// </summary>
        /// <param name="leftIt">A "from" enumerator.</param>
        /// <param name="rightIt">A "to" enumerator.</param>
        /// <returns>True if lists are identical. False otherwise.</returns>
        public static bool Compare(IEnumerator leftIt, IEnumerator rightIt)
        {
            if (ReferenceEquals(leftIt, rightIt))
                return true;
            if (ReferenceEquals(leftIt, null) || ReferenceEquals(rightIt, null))
                return false;

            bool hasLeftNext;
            bool hasRightNext;
            while (true)
            {
                hasLeftNext = leftIt.MoveNext();
                hasRightNext = rightIt.MoveNext();
                if (!hasLeftNext || !hasRightNext)
                    break;

                if (!Equals(leftIt.Current, rightIt.Current))
                    return false;
            }

            // If there is any left element
            if (hasLeftNext != hasRightNext)
                return false;

            return true;
        }

        /// <summary>
        /// Compares two collection, element by elements.
        /// </summary>
        /// <param name="first">The collection to compare from.</param>
        /// <param name="second">The colllection to compare to.</param>
        /// <returns>True if lists are identical (but no necessarely of the same time). False otherwise.</returns>
        public static bool Compare<TKey, TValue>(IDictionary<TKey, TValue> first, IDictionary<TKey, TValue> second)
        {
            if (ReferenceEquals(first, second)) return true;
            if (ReferenceEquals(first, null) || ReferenceEquals(second, null)) return false;
            if (first.Count != second.Count) return false;

            var comparer = EqualityComparer<TValue>.Default;

            foreach (var keyValue in first)
            {
                TValue secondValue;
                if (!second.TryGetValue(keyValue.Key, out secondValue)) return false;
                if (!comparer.Equals(keyValue.Value, secondValue)) return false;
            }

            // Check that all keys in second are in first
            return second.Keys.All(first.ContainsKey);
        }

        public static bool Compare<T>(T[] left, T[] right)
        {
            if (ReferenceEquals(left, right))
                return true;
            if (ReferenceEquals(left, null) || ReferenceEquals(right, null))
                return false;

            if (left.Length != right.Length)
                return false;

            var comparer = EqualityComparer<T>.Default;
            for (var i = 0; i < left.Length; ++i)
            {
                if (!comparer.Equals(left[i], right[i]))
                    return false;
            }

            return true;
        }

        /// <summary>
        /// Compares two collection, element by elements.
        /// </summary>
        /// <param name="left">The collection to compare from.</param>
        /// <param name="right">The colllection to compare to.</param>
        /// <returns>True if lists are identical (but no necessarely of the same time). False otherwise.</returns>
        public static bool Compare<T>(ICollection<T> left, ICollection<T> right)
        {
            if (ReferenceEquals(left, right))
                return true;
            if (ReferenceEquals(left, null) || ReferenceEquals(right, null))
                return false;

            if (left.Count != right.Count)
                return false;

            var count = 0;
            var leftIt = left.GetEnumerator();
            var rightIt = right.GetEnumerator();
            var comparer = EqualityComparer<T>.Default;
            while (leftIt.MoveNext() && rightIt.MoveNext())
            {
                if (!comparer.Equals(leftIt.Current, rightIt.Current))
                    return false;
                count++;
            }

            // Just double check to make sure that the iterator actually returns
            // the exact number of elements
            if (count != left.Count)
                return false;

            return true;
        }

        /// <summary>
        /// Swaps the value between two references.
        /// </summary>
        /// <typeparam name="T">Type of a data to swap.</typeparam>
        /// <param name="left">The left value.</param>
        /// <param name="right">The right value.</param>
        public static void Swap<T>(ref T left, ref T right)
        {
            var temp = left;
            left = right;
            right = temp;
        }

        /// <summary>
        /// Suspends current thread for a <see cref="sleepTime"/>.
        /// </summary>
        /// <param name="sleepTime">The duration of sleep.</param>
        public static void Sleep(TimeSpan sleepTime)
        {
            var ms = (long)sleepTime.TotalMilliseconds;
            if (ms < 0 || ms > int.MaxValue)
            {
                throw new ArgumentOutOfRangeException(nameof(sleepTime), "Sleep time must be a duration less than '2^31 - 1' milliseconds.");
            }
            // MH PORTED NativeInvoke.Sleep((int)ms);
						Thread.Sleep( (int)ms );
        }

        /// <summary>
        /// Suspends current thread for a <see cref="sleepTimeInMillis"/>.
        /// </summary>
        /// <param name="sleepTimeInMillis">The duration of sleep in milliseconds.</param>
        public static void Sleep(int sleepTimeInMillis)
        {
          // MH PORTED NativeInvoke.Sleep(sleepTimeInMillis);
					Thread.Sleep( sleepTimeInMillis );
				}

		/// <summary>
		/// Writes the specified T data to a memory location.
		/// </summary>
		/// <typeparam name="T">Type of a data to write</typeparam>
		/// <param name="destination">Memory location to write to.</param>
		/// <param name="data">The data to write.</param>
		internal static void UnsafeWrite<T>(IntPtr destination, ref T data)
        {
            unsafe
            {
                Interop.CopyInline((void*)destination, ref data);
            }
        }

        /// <summary>
        /// Reads the specified T data from a memory location.
        /// </summary>
        /// <typeparam name="T">Type of a data to read</typeparam>
        /// <param name="source">Memory location to read from.</param>
        /// <param name="data">The data write to.</param>
        internal static void UnsafeReadOut<T>(IntPtr source, out T data)
        {
            unsafe
            {
                Interop.CopyInlineOut(out data, (void*)source);
            }
        }

        /// <summary>
        /// Return the sizeof a struct from a CLR. Equivalent to sizeof operator but works on generics too.
        /// </summary>
        /// <typeparam name="T">a struct to evaluate</typeparam>
        /// <returns>sizeof this struct</returns>
        internal static int UnsafeSizeOf<T>()
        {
            return Interop.SizeOf<T>();
        }

        /// <summary>
        /// Linq assisted full tree iteration and collection in a single line.
        /// Warning, could be slow.
        /// </summary>
        /// <typeparam name="T">The type to iterate.</typeparam>
        /// <param name="root">The root item</param>
        /// <param name="childrenF">The function to retrieve a child</param>
        public static IEnumerable<T> IterateTree<T>(T root, Func<T, IEnumerable<T>> childrenF)
        {
            var q = new List<T> { root };
            while (q.Any())
            {
                var c = q[0];
                q.RemoveAt(0);
                q.AddRange(childrenF(c) ?? Enumerable.Empty<T>());
                yield return c;
            }
        }

        /// <summary>
        /// Converts a <see cref="Stopwatch" /> raw time to a <see cref="TimeSpan" />.
        /// </summary>
        /// <param name="delta">The delta.</param>
        /// <returns>The <see cref="TimeSpan" />.</returns>
        public static TimeSpan ConvertRawToTimestamp(long delta)
        {
            return new TimeSpan(delta == 0 ? 0 : (delta * TimeSpan.TicksPerSecond) / Stopwatch.Frequency);
        }
    }
}