69 lines
1.6 KiB
C#
69 lines
1.6 KiB
C#
using Obfuz.Emit;
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Obfuz.Utils
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{
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public class RandomWithKey : IRandom
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{
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// LCG 参数（使用经典的数值）
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private const long a = 1664525;
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private const long c = 1013904223;
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private const long m = 4294967296; // 2^32
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private readonly int[] _key;
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private int _nextIndex;
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private int _seed;
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public RandomWithKey(byte[] key, int seed)
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{
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_key = ConvertToIntKey(key);
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_seed = seed;
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}
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private static int[] ConvertToIntKey(byte[] key)
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{
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// ignore last bytes if not aligned to 4
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int align4Length = key.Length / 4;
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int[] intKey = new int[align4Length];
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Buffer.BlockCopy(key, 0, intKey, 0, align4Length * 4);
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return intKey;
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}
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public int NextInt(int min, int max)
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{
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return min + NextInt(max - min);
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}
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public int NextInt(int max)
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{
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return (int)((uint)NextInt() % (uint)max);
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}
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private int GetNextKeyByte()
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{
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if (_nextIndex >= _key.Length)
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{
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_nextIndex = 0;
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}
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return _key[_nextIndex++];
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}
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public int NextInt()
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{
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_seed = (int)((a * _seed + c) % m);
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return _seed ^ GetNextKeyByte();
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}
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public long NextLong()
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{
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return ((long)NextInt() << 32) | (uint)NextInt();
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}
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}
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}
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