CRC-16校验，校验结果是2个字节，高字节在前，低字节在后，校验的多项式为G(X) = X^16 + X^12 + X^5 + 1。可是就是校验不对，请高手解决.

[angelmd]

public byte[] CRC(byte[] ArrB)
{
byte CRC16Lo, CRC16Hi;
byte CL, CH;
byte SaveHi, SaveLo;
int i, Flag;

CRC16Lo = 0xFF;
CRC16Hi = 0xFF;
CL = 0x21;
CH = 0x10;

for (i = 0; i < ArrB.Length - 2; i++)
{
CRC16Lo = Convert.ToByte(CRC16Lo ^ ArrB[i]);
for (Flag = 0; Flag < 8; Flag++)
{
SaveHi = CRC16Hi;
SaveLo = CRC16Lo;
CRC16Hi = Convert.ToByte(CRC16Hi / 2);
CRC16Lo = Convert.ToByte(CRC16Lo / 2);
if ((SaveHi & 0x1) == 0x1)
{
CRC16Lo = Convert.ToByte(CRC16Lo | 0x80);
}
if ((SaveLo & 0x1) == 0x1)
{
CRC16Hi = Convert.ToByte(CRC16Hi ^ CH);
CRC16Lo = Convert.ToByte(CRC16Lo ^ CL);
}
}
}

//result[result.Length - 1] = CRC16Lo;
//result[result.Length] = CRC16Hi;
return new byte[] { CRC16Hi, CRC16Lo };
}

[angelmd]

各位高手给点帮助啊,帮忙帮我看一下这段代码啊,小弟在这里先谢谢了!!!!!!!!!!

[Q_282898034]

看样子挺费脑子，楼主加到120分估计会有高人现身

[angelmd]

输入：{0, 1, 9, 7}
校验结果为16进制：{27, c5}

[angelmd]

已经把问题的点数加到120分了，高手们快来帮我解答下吧，小弟不胜感激！！！！！！！！！！！！

[王集鹄]

{0,1,9,7}计算出的结果是：{0xA5,0x05}
....
CRC16是个标准

[王集鹄]

贴出几个测试用例用来验证

比如：
输入：{1, 2, 3, 4}
输出：{5, 6}

输入：{0, 8, 9, 255}
输出：{5, 6}

之类。

[angelmd]

你说的这个结果是crc16的结果，我要算的是CRC-CCITT的结果。我要的校验多项式为G(X) = X^16 + X^12 + X^5 + 1.而不是G(X) = X^16 + X^15 + X^2 + 1

[王集鹄]

http://topic.csdn.net/u/20070221/23/a94474d8-cab8-486e-9e09-816bad2b17e1.html

CCITT上次也做过，但结果算出来和楼主的也不一样？楼主确定你的测试用例是对的？
{0, 1, 9, 7}-》{27, c5}怎么还有个“c5”十六进制？

public sealed class CRCCCITT
{
    private static ushort[] CCITT_TABLE =   
    { 
        0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF, 
        0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7, 
        0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E, 
        0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876, 
        0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD, 
        0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5, 
        0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C, 
        0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974, 
        0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB, 
        0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3, 
        0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A, 
        0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72, 
        0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9, 
        0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1, 
        0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738, 
        0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70, 
        0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7, 
        0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF, 
        0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036, 
        0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E, 
        0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5, 
        0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD, 
        0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134, 
        0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C, 
        0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3, 
        0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB, 
        0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232, 
        0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A, 
        0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1, 
        0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9, 
        0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330, 
        0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78 
    };
    public static ushort CRC(byte[] ABytes)
    {
        ushort Result = 0;
        foreach (byte vByte in ABytes)
            Result = (ushort)(CCITT_TABLE[(Result ^ vByte) & 0xff] ^ (Result >> 8));
        return Result;
    }
}

private void button1_Click(object sender, EventArgs e)
{
    byte[] vBuffer =   { 0xfc, 0x05, 0x11 };
    ushort vCRC = CRCCCITT.CRC(vBuffer);
    Text = BitConverter.ToString(BitConverter.GetBytes(vCRC)); 
}

[angelmd]

通过串口发送的是{0x30，0x31，0x39，0x37}，得到的校验结果应该是{0x27,0xC5}，楼上的结果还是不对啊。还有你提供的Crc_Table是不是不对啊，还是恳求高手给予帮助。

[angelmd]

我的这个问题沉了这么长时间了，怎么就没有高手来给我解答下啊，小弟在苦苦地煎熬等待中。。。。。。。。。。。。。。。。。。。。

[han_shuhua]

public class Crc16
{
public byte[] crc_table =
{
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01,
0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01,
0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81,
0x40,0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5,
0xC4,0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9,
0x09,0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F,
0xDD,0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13,
0xD3,0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32, 0x36, 0xF6,
0xF7,0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA,
0x3A,0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA,
0xEE,0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6,
0x26,0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3,
0xA2,0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF,
0x6F,0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79,
0xBB,0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75,
0xB5,0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0, 0x50, 0x90,
0x91,0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C,
0x5C,0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98,
0x88,0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C,
0x8C,0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81,
0x80,0x40
};


public int crc16(byte[] modbusframe,int Length)
{
int i;
int index;
int crc_Low = 0xFF;
int crc_High = 0xFF;

for (i = 0; i<Length; i++)
{
index = crc_High ^ (char)modbusframe[i];
crc_High = crc_Low ^ crc_table[index];
crc_Low = (byte)crc_table[index + 256];
}

return crc_High*256+crc_Low;
}

public byte[] CRC16Bytes(byte[] bytes)
{
int crc = crc16(bytes,bytes.Length);
return new byte[] { (byte)(crc >> 8), (byte)(crc & 0x00ff) };
}
}

[netsmu]

楼上的太感谢了，你真牛啊，完全正确