// <copyright file="SystemCrypto.cs" company="Math.NET">
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// Math.NET Numerics, part of the Math.NET Project
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// http://numerics.mathdotnet.com
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// http://github.com/mathnet/mathnet-numerics
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//
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// Copyright (c) 2009-2014 Math.NET
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//
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// Permission is hereby granted, free of charge, to any person
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// obtaining a copy of this software and associated documentation
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// files (the "Software"), to deal in the Software without
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// restriction, including without limitation the rights to use,
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// copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following
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// conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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// OTHER DEALINGS IN THE SOFTWARE.
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// </copyright>
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using System;
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using System.Collections.Generic;
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using System.Security.Cryptography;
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#if !NETSTANDARD1_3
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using System.Runtime;
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#endif
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namespace IStation.Numerics.Random
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{
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/// <summary>
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/// A random number generator based on the <see cref="System.Security.Cryptography.RandomNumberGenerator"/> class in the .NET library.
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/// </summary>
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public sealed class CryptoRandomSource : RandomSource, IDisposable
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{
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const double Reciprocal = 1.0/4294967296.0; // 1.0/(uint.MaxValue + 1.0)
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readonly RandomNumberGenerator _crypto;
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/// <summary>
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/// Construct a new random number generator with a random seed.
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/// </summary>
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/// <remarks>Uses <see cref="System.Security.Cryptography.RandomNumberGenerator"/> and uses the value of
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/// <see cref="Control.ThreadSafeRandomNumberGenerators"/> to set whether the instance is thread safe.</remarks>
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public CryptoRandomSource()
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{
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_crypto = RandomNumberGenerator.Create();
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}
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/// <summary>
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/// Construct a new random number generator with random seed.
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/// </summary>
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/// <param name="rng">The <see cref="RandomNumberGenerator"/> to use.</param>
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/// <remarks>Uses the value of <see cref="Control.ThreadSafeRandomNumberGenerators"/> to set whether the instance is thread safe.</remarks>
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public CryptoRandomSource(RandomNumberGenerator rng)
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{
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_crypto = rng;
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}
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/// <summary>
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/// Construct a new random number generator with random seed.
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/// </summary>
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/// <remarks>Uses <see cref="System.Security.Cryptography.RandomNumberGenerator"/></remarks>
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/// <param name="threadSafe">if set to <c>true</c> , the class is thread safe.</param>
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public CryptoRandomSource(bool threadSafe) : base(threadSafe)
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{
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_crypto = RandomNumberGenerator.Create();
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}
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/// <summary>
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/// Construct a new random number generator with random seed.
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/// </summary>
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/// <param name="rng">The <see cref="RandomNumberGenerator"/> to use.</param>
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/// <param name="threadSafe">if set to <c>true</c> , the class is thread safe.</param>
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public CryptoRandomSource(RandomNumberGenerator rng, bool threadSafe) : base(threadSafe)
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{
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_crypto = rng;
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}
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/// <summary>
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/// Fills the elements of a specified array of bytes with random numbers in full range, including zero and 255 (<see cref="F:System.Byte.MaxValue"/>).
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/// </summary>
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protected override void DoSampleBytes(byte[] buffer)
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{
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_crypto.GetBytes(buffer);
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}
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/// <summary>
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/// Returns a random double-precision floating point number greater than or equal to 0.0, and less than 1.0.
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/// </summary>
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protected sealed override double DoSample()
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{
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var bytes = new byte[4];
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_crypto.GetBytes(bytes);
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return BitConverter.ToUInt32(bytes, 0)*Reciprocal;
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}
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/// <summary>
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/// Returns a random 32-bit signed integer greater than or equal to zero and less than <see cref="F:System.Int32.MaxValue"/>
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/// </summary>
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protected sealed override int DoSampleInteger()
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{
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var bytes = new byte[4];
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_crypto.GetBytes(bytes);
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uint uint32 = BitConverter.ToUInt32(bytes, 0);
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int int31 = (int)(uint32 >> 1);
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if (int31 == int.MaxValue)
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{
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return DoSampleInteger();
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}
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return int31;
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}
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public void Dispose()
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{
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_crypto.Dispose();
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}
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/// <summary>
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/// Fills an array with random numbers greater than or equal to 0.0 and less than 1.0.
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/// </summary>
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/// <remarks>Supports being called in parallel from multiple threads.</remarks>
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public static void Doubles(double[] values)
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{
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var bytes = new byte[values.Length*4];
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using (var rnd = RandomNumberGenerator.Create())
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{
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rnd.GetBytes(bytes);
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}
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for (int i = 0; i < values.Length; i++)
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{
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values[i] = BitConverter.ToUInt32(bytes, i*4)*Reciprocal;
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}
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}
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/// <summary>
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/// Returns an array of random numbers greater than or equal to 0.0 and less than 1.0.
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/// </summary>
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/// <remarks>Supports being called in parallel from multiple threads.</remarks>
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[TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
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public static double[] Doubles(int length)
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{
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var data = new double[length];
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Doubles(data);
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return data;
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}
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/// <summary>
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/// Returns an infinite sequence of random numbers greater than or equal to 0.0 and less than 1.0.
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/// </summary>
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/// <remarks>Supports being called in parallel from multiple threads.</remarks>
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public static IEnumerable<double> DoubleSequence()
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{
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var rnd = RandomNumberGenerator.Create();
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var buffer = new byte[1024*4];
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while (true)
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{
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rnd.GetBytes(buffer);
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for (int i = 0; i < buffer.Length; i += 4)
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{
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yield return BitConverter.ToUInt32(buffer, i)*Reciprocal;
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}
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}
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}
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}
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}
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