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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using System.Runtime;
using Internal.Runtime.CompilerServices;
namespace System.Threading
{
//
// Methods for accessing memory with volatile semantics.
//
public static unsafe class Volatile
{
#region Boolean
private struct VolatileBoolean { public volatile bool Value; }
public static bool Read(ref bool location)
{
return Unsafe.As<bool, VolatileBoolean>(ref location).Value;
}
public static void Write(ref bool location, bool value)
{
Unsafe.As<bool, VolatileBoolean>(ref location).Value = value;
}
#endregion
#region Byte
private struct VolatileByte { public volatile byte Value; }
public static byte Read(ref byte location)
{
return Unsafe.As<byte, VolatileByte>(ref location).Value;
}
public static void Write(ref byte location, byte value)
{
Unsafe.As<byte, VolatileByte>(ref location).Value = value;
}
#endregion
#region Double
public static double Read(ref double location)
{
long result = Read(ref Unsafe.As<double, long>(ref location));
return *(double*)&result;
}
public static void Write(ref double location, double value)
{
Write(ref Unsafe.As<double, long>(ref location), *(long*)&value);
}
#endregion
#region Int16
private struct VolatileInt16 { public volatile short Value; }
public static short Read(ref short location)
{
return Unsafe.As<short, VolatileInt16>(ref location).Value;
}
public static void Write(ref short location, short value)
{
Unsafe.As<short, VolatileInt16>(ref location).Value = value;
}
#endregion
#region Int32
private struct VolatileInt32 { public volatile int Value; }
public static int Read(ref int location)
{
return Unsafe.As<int, VolatileInt32>(ref location).Value;
}
public static void Write(ref int location, int value)
{
Unsafe.As<int, VolatileInt32>(ref location).Value = value;
}
#endregion
#region Int64
public static long Read(ref long location)
{
#if BIT64
return (Int64)Unsafe.As<Int64, VolatileIntPtr>(ref location).Value;
#else
return Interlocked.CompareExchange(ref location, 0, 0);
#endif
}
public static void Write(ref long location, long value)
{
#if BIT64
Unsafe.As<Int64, VolatileIntPtr>(ref location).Value = (IntPtr)value;
#else
Interlocked.Exchange(ref location, value);
#endif
}
#endregion
#region IntPtr
private struct VolatileIntPtr { public volatile IntPtr Value; }
public static IntPtr Read(ref IntPtr location)
{
return Unsafe.As<IntPtr, VolatileIntPtr>(ref location).Value;
}
public static void Write(ref IntPtr location, IntPtr value)
{
fixed (IntPtr* p = &location)
{
((VolatileIntPtr*)p)->Value = value;
}
}
#endregion
#region SByte
private struct VolatileSByte { public volatile sbyte Value; }
[CLSCompliant(false)]
public static sbyte Read(ref sbyte location)
{
return Unsafe.As<sbyte, VolatileSByte>(ref location).Value;
}
[CLSCompliant(false)]
public static void Write(ref sbyte location, sbyte value)
{
Unsafe.As<sbyte, VolatileSByte>(ref location).Value = value;
}
#endregion
#region Single
private struct VolatileSingle { public volatile float Value; }
public static float Read(ref float location)
{
return Unsafe.As<float, VolatileSingle>(ref location).Value;
}
public static void Write(ref float location, float value)
{
Unsafe.As<float, VolatileSingle>(ref location).Value = value;
}
#endregion
#region UInt16
private struct VolatileUInt16 { public volatile ushort Value; }
[CLSCompliant(false)]
public static ushort Read(ref ushort location)
{
return Unsafe.As<ushort, VolatileUInt16>(ref location).Value;
}
[CLSCompliant(false)]
public static void Write(ref ushort location, ushort value)
{
Unsafe.As<ushort, VolatileUInt16>(ref location).Value = value;
}
#endregion
#region UInt32
private struct VolatileUInt32 { public volatile uint Value; }
[CLSCompliant(false)]
public static uint Read(ref uint location)
{
return Unsafe.As<uint, VolatileUInt32>(ref location).Value;
}
[CLSCompliant(false)]
public static void Write(ref uint location, uint value)
{
Unsafe.As<uint, VolatileUInt32>(ref location).Value = value;
}
#endregion
#region UInt64
[CLSCompliant(false)]
public static ulong Read(ref ulong location)
{
return (ulong)Read(ref Unsafe.As<ulong, long>(ref location));
}
[CLSCompliant(false)]
public static void Write(ref ulong location, ulong value)
{
Write(ref Unsafe.As<ulong, long>(ref location), (long)value);
}
#endregion
#region UIntPtr
private struct VolatileUIntPtr { public volatile UIntPtr Value; }
[CLSCompliant(false)]
public static UIntPtr Read(ref UIntPtr location)
{
return Unsafe.As<UIntPtr, VolatileUIntPtr>(ref location).Value;
}
[CLSCompliant(false)]
public static void Write(ref UIntPtr location, UIntPtr value)
{
Unsafe.As<UIntPtr, VolatileUIntPtr>(ref location).Value = value;
}
#endregion
#region T
private struct VolatileObject { public volatile object Value; }
public static T Read<T>(ref T location) where T : class
{
return Unsafe.As<T>(Unsafe.As<T, VolatileObject>(ref location).Value);
}
public static void Write<T>(ref T location, T value) where T : class
{
Unsafe.As<T, VolatileObject>(ref location).Value = value;
}
#endregion
}
}
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