CRC32算法C#中的实现

代码如下：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Text;
 4 using System.IO;
 5 
 6 namespace GetCRC32
 7 {
 8     class CRC32Cls
 9     {
10         protected ulong[] Crc32Table;
11         //生成CRC32码表
12         public void GetCRC32Table() 
13         {
14             ulong Crc;
15             Crc32Table = new ulong[256];
16             int i,j;
17             for(i = 0;i < 256; i++) 
18             {
19                 Crc = (ulong)i;
20                 for (j = 8; j > 0; j--)
21                 {
22                     if ((Crc & 1) == 1)
23                         Crc = (Crc >> 1) ^ 0xEDB88320;
24                     else
25                         Crc >>= 1;
26                 }
27                 Crc32Table[i] = Crc;
28             }
29         }
30 
31         //获取字符串的CRC32校验值
32         public ulong GetCRC32Str(string sInputString)
33         {
34             //生成码表
35             GetCRC32Table();
36             byte[] buffer = System.Text.ASCIIEncoding.ASCII.GetBytes(sInputString);
37             ulong value = 0xffffffff;
38             int len = buffer.Length;
39             for (int i = 0; i < len; i++)
40             {
41                 value = (value >> 8) ^ Crc32Table[(value & 0xFF)^ buffer[i]];
42             }
43             return value ^ 0xffffffff; 
44         }
45     }
46 }

调用代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace GetCRC32
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            CRC32Cls CRC = new CRC32Cls();
            textBox2.Text = String.Format("{0:X8}", CRC.GetCRC32Str(textBox1.Text));
        }

        private void button2_Click(object sender, EventArgs e)
        {

        }
    }
}