124 lines
4.1 KiB
C#
124 lines
4.1 KiB
C#
/*
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*
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* (c) Copyright Ascensio System Limited 2010-2018
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*
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* This program is freeware. You can redistribute it and/or modify it under the terms of the GNU
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* General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html).
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* In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that
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* Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
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*
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* THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
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* FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
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*
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* You can contact Ascensio System SIA by email at sales@onlyoffice.com
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*
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* The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display
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* Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
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*
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* Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains
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* relevant author attributions when distributing the software. If the display of the logo in its graphic
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* form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE"
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* in every copy of the program you distribute.
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* Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
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*
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*/
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using System;
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namespace ASC.Common.Security
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{
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public class AscRandom : Random
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{
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private int inext;
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private int inextp;
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private const int MBIG = int.MaxValue;
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private const int MSEED = 161803398;
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private const int MZ = 0;
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private readonly int[] seeds;
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public AscRandom() : this(Environment.TickCount)
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{
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}
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public AscRandom(int seed)
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{
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seeds = new int[56];
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var num4 = (seed == int.MinValue) ? int.MaxValue : Math.Abs(seed);
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var num2 = 161803398 - num4;
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seeds[^1] = num2;
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var num3 = 1;
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for (var i = 1; i < seeds.Length - 1; i++)
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{
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var index = (21 * i) % (seeds.Length - 1);
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seeds[index] = num3;
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num3 = num2 - num3;
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if (num3 < 0)
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{
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num3 += int.MaxValue;
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}
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num2 = seeds[index];
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}
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for (var j = 1; j < 5; j++)
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{
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for (var k = 1; k < seeds.Length; k++)
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{
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seeds[k] -= seeds[1 + ((k + 30) % (seeds.Length - 1))];
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if (seeds[k] < 0)
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{
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seeds[k] += int.MaxValue;
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}
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}
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}
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inext = 0;
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inextp = 21;
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}
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public override 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(nameof(maxValue));
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}
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return (int)(InternalSample() * 4.6566128752457969E-10 * maxValue);
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}
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public override void NextBytes(byte[] buffer)
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{
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if (buffer == null) throw new ArgumentNullException(nameof(buffer));
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for (var i = 0; i < buffer.Length; i++)
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{
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buffer[i] = (byte)(InternalSample() % (byte.MaxValue + 1));
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}
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}
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private int InternalSample()
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{
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var inext = this.inext;
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var inextp = this.inextp;
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if (++inext >= seeds.Length - 1)
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{
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inext = 1;
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}
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if (++inextp >= seeds.Length - 1)
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{
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inextp = 1;
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}
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var num = seeds[inext] - seeds[inextp];
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if (num == int.MaxValue)
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{
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num--;
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}
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if (num < 0)
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{
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num += int.MaxValue;
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}
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seeds[inext] = num;
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this.inext = inext;
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this.inextp = inextp;
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return num;
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}
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}
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} |