// 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 ) )
			{
				log.info( $"Creating directory {path}" );
				Directory.CreateDirectory( path );
			}
			else
			{
				log.debug( $"{path} already exists." );
			}

		}


		/// <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 );
		}
	}
}