148 lines
3.5 KiB
C#
148 lines
3.5 KiB
C#
#region copyright
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// ------------------------------------------------------
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// Copyright (C) Dmitriy Yukhanov [https://codestage.net]
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// ------------------------------------------------------
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#endregion
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namespace CodeStage.AntiCheat.Utils
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{
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using System;
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/// <summary>
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/// Random utility which can be used from background threads.
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/// </summary>
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public static class ThreadSafeRandom
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{
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private static readonly Random Global = new Random();
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[ThreadStatic]
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private static Random local;
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/// <summary>
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/// Generates random <c>int</c> number within specified range.
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/// </summary>
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/// <param name="minInclusive">Minimal value, inclusive.</param>
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/// <param name="maxExclusive">Maximum value, exclusive.</param>
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/// <returns>Random value in specified range.</returns>
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public static int Next(int minInclusive, int maxExclusive)
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{
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var inst = local;
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if (inst != null)
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{
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return inst.Next(minInclusive, maxExclusive);
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}
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int seed;
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lock (Global)
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{
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seed = Global.Next();
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}
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local = inst = new Random(seed);
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return inst.Next(minInclusive, maxExclusive);
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}
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/// <summary>
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/// Generates random <c>long</c> number within specified range.
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/// </summary>
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/// <param name="minInclusive">Minimal value, inclusive.</param>
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/// <param name="maxExclusive">Maximum value, exclusive.</param>
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/// <returns>Random value in specified range.</returns>
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public static long NextLong(long minInclusive, long maxExclusive)
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{
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var inst = local;
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if (inst != null)
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{
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return NextLong(inst, minInclusive, maxExclusive);
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}
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int seed;
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lock (Global)
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{
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seed = Global.Next();
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}
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local = inst = new Random(seed);
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return NextLong(inst, minInclusive, maxExclusive);
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}
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/// <summary>
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/// Fills passed buffer with random bytes.
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/// </summary>
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/// <param name="buffer">Buffer filled with random bytes.</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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throw new ArgumentNullException(nameof(buffer));
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var inst = local;
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if (inst != null)
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{
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inst.NextBytes(buffer);
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return;
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}
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int seed;
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lock (Global)
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{
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seed = Global.Next();
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}
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local = inst = new Random(seed);
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inst.NextBytes(buffer);
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}
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/// <summary>
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/// Fills passed buffer with random <c>char</c> values.
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/// </summary>
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/// <param name="buffer">Buffer filled with random <c>char</c> values.</param>
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public static void NextChars(char[] buffer)
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{
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if (buffer == null)
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throw new ArgumentNullException(nameof(buffer));
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var inst = local;
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if (inst != null)
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{
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NextChars(inst, buffer);
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return;
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}
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int seed;
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lock (Global)
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{
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seed = Global.Next();
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}
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local = inst = new Random(seed);
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NextChars(inst, buffer);
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}
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private static long NextLong(Random random, long minInclusive, long maxExclusive)
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{
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var result = (long)random.Next((int)(minInclusive >> 32), (int)(maxExclusive >> 32));
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result <<= 32;
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result |= (uint)random.Next((int)minInclusive, (int)maxExclusive);
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return result;
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}
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private static void NextChars(Random random, char[] buffer)
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{
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for (var i = 0; i < buffer.Length; ++i)
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{
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// capping to byte value here to not exceed
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// 56 bit crypto keys length requirement by
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// Apple to avoid cryptography declaration
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buffer[i] = (char) (random.Next() % 256);
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}
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}
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}
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} |