csharp/src/Google.Protobuf.Test/SampleNaNs.cs

#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2017 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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#endregion

using System;

namespace Google.Protobuf
{
    /// <summary>
    /// Samples of different not-a-number values, for testing equality comparisons.
    /// </summary>
    public static class SampleNaNs
    {
        public static double Regular { get; } = double.NaN;

        // Signalling bit is inverted compared with double.NaN. Doesn't really matter
        // whether that makes it quiet or signalling - it's different.
        public static double SignallingFlipped { get; } = 
            BitConverter.Int64BitsToDouble(BitConverter.DoubleToInt64Bits(double.NaN) ^ -0x8000_0000_0000_0000L);

        // A bit in the middle of the mantissa is flipped; this difference is preserved when casting to float.
        public static double PayloadFlipped { get; } =
            BitConverter.Int64BitsToDouble(BitConverter.DoubleToInt64Bits(double.NaN) ^ 0x1_0000_0000L);
    }
}