CnC_Remastered_Collection

Command and Conquer: Red Alert
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CRC.cs (2017B)

      1 //
      2 // Copyright 2020 Electronic Arts Inc.
      3 //
      4 // The Command & Conquer Map Editor and corresponding source code is free 
      5 // software: you can redistribute it and/or modify it under the terms of 
      6 // the GNU General Public License as published by the Free Software Foundation, 
      7 // either version 3 of the License, or (at your option) any later version.
      8 
      9 // The Command & Conquer Map Editor and corresponding source code is distributed 
     10 // in the hope that it will be useful, but with permitted additional restrictions 
     11 // under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT 
     12 // distributed with this program. You should have received a copy of the 
     13 // GNU General Public License along with permitted additional restrictions 
     14 // with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection
     15 using System;
     16 
     17 namespace MobiusEditor.Utility
     18 {
     19     public class CRC
     20     {
     21         static CRC()
     22         {
     23             for (var i = 0U; i < 256U; ++i)
     24             {
     25                 uint crc = i;
     26                 for (var j = 0U; j < 8U; ++j)
     27                 {
     28                     if ((crc & 1U) != 0U)
     29                     {
     30                         crc = (crc >> 1) ^ polynomial;
     31                     }
     32                     else
     33                     {
     34                         crc >>= 1;
     35                     }
     36                 }
     37                 crcTable[i] = crc;
     38             }
     39         }
     40 
     41         public static uint Calculate(byte[] bytes)
     42         {
     43             if (bytes == null)
     44             {
     45                 throw new ArgumentNullException("bytes");
     46             }
     47 
     48             uint remainder = 0xFFFFFFFFU;
     49             for (var i = 0; i < bytes.Length; ++i)
     50             {
     51                 uint index = (remainder & 0xFF) ^ bytes[i];
     52                 remainder = (remainder >> 8) ^ crcTable[index];
     53             }
     54             return ~remainder;
     55         }
     56 
     57         private static readonly uint[] crcTable = new uint[256];
     58         private const uint polynomial = 0xEDB88320;
     59     }
     60 }