AtomicBoolean.cs

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// AtomicBoolean.cs
//
// Copyright (c) 2008 Jérémie "Garuma" Laval
//
// 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.
//
//

using System;

#if INSIDE_MONO_PARALLEL
using System.Threading;

namespace Mono.Threading
#else
namespace System.Threading
#endif
{
#if INSIDE_MONO_PARALLEL
    public
#endif
    struct AtomicBooleanValue
    {
        int flag;
        const int UnSet = 0;
        const int Set = 1;

        public bool CompareAndExchange (bool expected, bool newVal)
        {
            int newTemp = newVal ? Set : UnSet;
            int expectedTemp = expected ? Set : UnSet;

            return AotInterlocked.CompareExchange (ref flag, newTemp, expectedTemp) == expectedTemp;
        }

        public static AtomicBooleanValue FromValue (bool value)
        {
            AtomicBooleanValue temp = new AtomicBooleanValue ();
            temp.Value = value;

            return temp;
        }

        public bool TrySet ()
        {
            return !Exchange (true);
        }

        public bool TryRelaxedSet ()
        {
            return flag == UnSet && !Exchange (true);
        }

        public bool Exchange (bool newVal)
        {
            int newTemp = newVal ? Set : UnSet;
            return AotInterlocked.Exchange (ref flag, newTemp) == Set;
        }

        public bool Value {
            get {
                return flag == Set;
            }
            set {
                Exchange (value);
            }
        }

        public bool Equals (AtomicBooleanValue rhs)
        {
            return this.flag == rhs.flag;
        }

        public override bool Equals (object rhs)
        {
            return rhs is AtomicBooleanValue ? Equals ((AtomicBooleanValue)rhs) : false;
        }

        public override int GetHashCode ()
        {
            return flag.GetHashCode ();
        }

        public static explicit operator bool (AtomicBooleanValue rhs)
        {
            return rhs.Value;
        }

        public static implicit operator AtomicBooleanValue (bool rhs)
        {
            return AtomicBooleanValue.FromValue (rhs);
        }
    }

#if INSIDE_MONO_PARALLEL
    public
#endif
    class AtomicBoolean
    {
        int flag;
        const int UnSet = 0;
        const int Set = 1;

        public bool CompareAndExchange (bool expected, bool newVal)
        {
            int newTemp = newVal ? Set : UnSet;
            int expectedTemp = expected ? Set : UnSet;

            return AotInterlocked.CompareExchange (ref flag, newTemp, expectedTemp) == expectedTemp;
        }

        public static AtomicBoolean FromValue (bool value)
        {
            AtomicBoolean temp = new AtomicBoolean ();
            temp.Value = value;

            return temp;
        }

        public bool TrySet ()
        {
            return !Exchange (true);
        }

        public bool TryRelaxedSet ()
        {
            return flag == UnSet && !Exchange (true);
        }

        public bool Exchange (bool newVal)
        {
            int newTemp = newVal ? Set : UnSet;
            return AotInterlocked.Exchange (ref flag, newTemp) == Set;
        }

        public bool Value {
            get {
                return flag == Set;
            }
            set {
                Exchange (value);
            }
        }

        public bool Equals (AtomicBoolean rhs)
        {
            return this.flag == rhs.flag;
        }

        public override bool Equals (object rhs)
        {
            return rhs is AtomicBoolean ? Equals ((AtomicBoolean)rhs) : false;
        }

        public override int GetHashCode ()
        {
            return flag.GetHashCode ();
        }

        public static explicit operator bool (AtomicBoolean rhs)
        {
            return rhs.Value;
        }

        public static implicit operator AtomicBoolean (bool rhs)
        {
            return AtomicBoolean.FromValue (rhs);
        }
    }
}