53 lines
1.4 KiB
C#
53 lines
1.4 KiB
C#
using System;
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using System.Buffers.Binary;
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namespace AssetStudio
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{
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public class XORShift128
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{
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public uint x = 0, y = 0, z = 0, w = 0, initseed = 0;
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const long SEED = 0x61C8864E7A143579;
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const uint MT19937 = 0x6C078965;
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public void InitSeed(int seed)
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{
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initseed = (uint)seed;
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x = (uint)seed;
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y = MT19937 * x + 1;
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z = MT19937 * y + 1;
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w = MT19937 * z + 1;
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}
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public uint XORShift()
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{
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uint t = x ^ (x << 11);
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x = y; y = z; z = w;
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return w = w ^ (w >> 19) ^ t ^ (t >> 8);
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}
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public uint NextUInt32()
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{
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return XORShift();
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}
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public int NextDecryptInt() => BinaryPrimitives.ReadInt32LittleEndian(NextDecrypt(4));
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public uint NextDecryptUInt() => BinaryPrimitives.ReadUInt32LittleEndian(NextDecrypt(4));
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public long NextDecryptLong() => BinaryPrimitives.ReadInt64LittleEndian(NextDecrypt(8));
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public byte[] NextDecrypt(int size)
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{
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var valueBytes = new byte[size];
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var key = size * initseed - SEED;
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var keyBytes = BitConverter.GetBytes(key);
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for (int i = 0; i < size; i++)
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{
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var val = NextUInt32();
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valueBytes[i] = keyBytes[val % 8];
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}
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return valueBytes;
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}
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}
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}
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