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132 lines
4.9 KiB
C#
132 lines
4.9 KiB
C#
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#region License Information (GPL v3)
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/*
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ShareX - A program that allows you to take screenshots and share any file type
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Copyright (c) 2007-2020 ShareX Team
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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Optionally you can also view the license at <http://www.gnu.org/licenses/>.
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*/
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#endregion License Information (GPL v3)
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using System;
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using System.Security.Cryptography;
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namespace ShareX.HelpersLib
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{
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// https://docs.microsoft.com/en-us/archive/msdn-magazine/2007/september/net-matters-tales-from-the-cryptorandom
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public static class RandomCrypto
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{
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private static readonly object randomLock = new object();
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private static readonly RNGCryptoServiceProvider random = new RNGCryptoServiceProvider();
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private static byte[] uint32Buffer = new byte[4];
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/// <summary>Returns a non-negative random integer.</summary>
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/// <returns>A 32-bit signed integer that is greater than or equal to 0 and less than <c>System.Int32.MaxValue.</c></returns>
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public static int Next()
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{
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lock (randomLock)
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{
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random.GetBytes(uint32Buffer);
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return BitConverter.ToInt32(uint32Buffer, 0) & 0x7FFFFFFF;
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}
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}
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/// <summary>Returns a non-negative random integer that is less than or equal to <paramref name="maxValue"/>.</summary>
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/// <param name="maxValue">The inclusive upper bound of the random number returned.</param>
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/// <returns>A 32-bit signed integer that is greater than or equal to 0 and less than or equal to <paramref name="maxValue"/>.</returns>
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public static int Next(int maxValue)
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{
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if (maxValue < 0)
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{
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throw new ArgumentOutOfRangeException("maxValue");
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}
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return Next(0, maxValue);
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}
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/// <summary>Returns a random integer that is within a specified range.</summary>
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/// <param name="minValue">The inclusive lower bound of the random number returned.</param>
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/// <param name="maxValue">The inclusive upper bound of the random number returned.</param>
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/// <returns>A 32-bit signed integer that is greater than or equal to <paramref name="minValue"/> and less than or equal to <paramref name="maxValue"/>.</returns>
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public static int Next(int minValue, int maxValue)
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{
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maxValue++;
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if (minValue > maxValue)
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{
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throw new ArgumentOutOfRangeException("minValue");
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}
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if (minValue == maxValue)
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{
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return minValue;
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}
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long diff = maxValue - minValue;
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lock (randomLock)
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{
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while (true)
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{
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random.GetBytes(uint32Buffer);
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uint rand = BitConverter.ToUInt32(uint32Buffer, 0);
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long max = 1 + (long)uint.MaxValue;
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long remainder = max % diff;
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if (rand < max - remainder)
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{
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return (int)(minValue + (rand % diff));
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}
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}
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}
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}
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/// <summary>Returns a random floating-point number that is greater than or equal to 0.0, and less than 1.0.</summary>
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/// <returns>A double-precision floating point number that is greater than or equal to 0.0, and less than 1.0.</returns>
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public static double NextDouble()
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{
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lock (randomLock)
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{
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random.GetBytes(uint32Buffer);
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uint rand = BitConverter.ToUInt32(uint32Buffer, 0);
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return rand / (1.0 + uint.MaxValue);
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}
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}
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/// <summary>Fills the elements of a specified array of bytes with random numbers.</summary>
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/// <param name="buffer">An array of bytes to contain random numbers.</param>
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public static void NextBytes(byte[] buffer)
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{
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if (buffer == null)
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{
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throw new ArgumentNullException("buffer");
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}
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lock (randomLock)
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{
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random.GetBytes(buffer);
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}
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}
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public static T Pick<T>(params T[] array)
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{
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return array[Next(array.Length - 1)];
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}
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}
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}
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