妯′簩榪愮畻// CrcMOD2鍑芥暟///////////////////////////////////////////////////////
// 浣滅敤錛氭ā2榪愮畻
// 鍙傛暟璇存槑錛?br>// m 鈥斺?nbsp;琚櫎鏁?br>// p 鈥斺?nbsp;闄ゆ暟
// 榪斿洖錛氫綑鏁?/span>
unsigned long CrcMOD2(unsigned long m, unsigned long p)
{
int m_bits = 0, p_bits = 0, a = 1, bit = 0, flag = 0;
unsigned long m_temp = m, p_temp = p;
unsigned long remainder = 0, andData = 0x00000001;
unsigned long dividend, divisor;
// 寰楀埌琚櫎鏁頒綅鏁?/span>
while (m_temp)
{
m_temp /= 2;
++m_bits;
}
// 寰楀埌闄ゆ暟浣嶆暟
while (p_temp)
{
p_temp /= 2;
++p_bits;
}
// 濡傛灉琚櫎鏁頒綅鏁板皬浜庨櫎鏁幫紝鍒欑洿鎺ヨ繑鍥炶闄ゆ暟浣滀負(fù)浣欐暟
if (m_bits < p_bits)
return m;
// 鍦ㄦ寮濮嬬涓嬈℃ā2榪愮畻
m_temp = m >> (m_bits - p_bits); // 琚櫎鏁板彸縐葷浉搴旂殑浣嶆暟
dividend = m_temp; // 寰楀埌絎竴嬈¤繘琛岃繍綆楃殑琚櫎鏁?/span>
divisor = p; // 寰楀埌闄ゆ暟
remainder = dividend ^ divisor; // 寰楀埌妯?榪愮畻鐨勭粨鏋滀綔涓轟綑鏁?/span>
m_bits -= p_bits; // 絎竴嬈¤綆楀畬鎴愶紝鍑忓幓宸茬粡璁＄畻榪囩殑浣嶆暟
while (m_bits)
{
if (!flag)
{
dividend = (remainder << 1); // 涓婁竴嬈″緱鍒扮殑浣欐暟浣滀負(fù)榪欐琚櫎鏁扮殑楂樹綅
m_temp = m >> (m_bits - 1);
bit = andData & m_temp;
dividend |= bit; // 鍘熻闄ゆ暟鐨勬煇涓浣嶄綔涓虹幇鍦ㄧ殑琚櫎鏁扮殑鏈浣庝綅
}
else
{
dividend <<= 1;
m_temp = m >> (m_bits - 1);
bit = andData & m_temp;
dividend |= bit;
}
// 姣旇緝闄ゆ暟鍜岃闄ゆ暟鐨勬渶楂樹綅澶у皬
if ((dividend & (andData << (p_bits - 1))) >= (divisor & (andData << (p_bits - 1))))
{
flag = 0;
remainder = dividend ^ divisor; // 寰楀埌妯?榪愮畻鐨勭粨鏋滀綔涓轟綑鏁?/span>
}
else
{
// 闇瑕佸熶綅
flag = 1;
}
--m_bits;
}
if (flag)
remainder = dividend;
return remainder;
}
銆銆CrcGetCode鍑芥暟鑾峰師濮嬫暟鎹拰CRC鐢熸垚澶氶」寮忥紝鍒╃敤妯′簩榪愮畻寰楀埌鏂扮殑鏁版嵁銆傜畻娉曞涓嬶細(xì)
緇欐暟鎹姞涓婃牎楠岀爜// CrcGetCode鍑芥暟///////////////////////////////////////////////////
// 浣滅敤錛氶氳繃鍘熷鏁版嵁涓嶤RC澶氶」寮忥紝寰楀埌鏁翠釜鏁版嵁鐨勭紪鐮?br>// 鍙傛暟璇存槑錛?br>// originalData 鈥斺?nbsp;鍘熷鏁版嵁
// crcPolynomial 鈥斺?nbsp;CRC鐢熸垚澶氶」寮?br>// 榪斿洖錛氬師濮嬫暟鎹?nbsp;+ 鏍￠獙鐮?/span>
int CrcGetCode(unsigned long originalData, unsigned long crcPolynomial)
{
unsigned long checkBits = 0, temp = crcPolynomial, m = originalData, fcs;
while (temp)
{
temp /= 2;
++checkBits; // 鏍￠獙浣嶄釜鏁板姞涓
}
-- checkBits; // 寰楀埌鏍￠獙浣嶄釜鏁幫紙姣旂敓鎴愬欏瑰紡灝?浣嶏級(jí)
m <<= checkBits; // 寰楀埌妯′簩榪愮畻鐨勮闄ゆ暟
if (checkBits == 0)
return m;
fcs = CrcMOD2(m, crcPolynomial);
m |= fcs; // 鍔犱笂FCS鏍￠獙瀛?/span>
return m; // 榪斿洖鏁翠釜緙栫爜
}
]]>