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int IsCheckSumRight(int iPos,int iKey)
{
//检查字符数组g_Data从iPos开始的iKey个字节异或结果是否为0
//是,返回1.否,返回0
char cSum = g_Data[iPos];
int i = 0;
for (i = 1;i < iKey;i++)
{
cSum ^= g_Data[iPos + i];
}
if (cSum == 0)
{
return 1;
}
return 0;
}
typedef struct
{
int m_iFrom;
int m_iTo;
char m_cResult;
}LOG;
char g_Data[MAX_DATA_LEN];
LOG g_Log[MAX_DATA_LEN];
int g_iCurLogCnt = 0;
char GetCheckSum(int iFrom,int iTo,int iIsCheckLog)
{
//计算g_Data从iFrom 到 iTo 的异或结果,
//iIsCheckLog = 1 检查g_Log再计算,iIsCheckLog = 0 直接计算
char cSum = g_Data[iFrom];
char cLeftResult = 0,cRightResult = 0,cLogResult = 0;
int i = 0,iFondLog = 0;
LOG *pLog;
if (iTo < iFrom)
{
//无效区段
return 0;
}
if (iIsCheckLog == 1)
{
for (i = 0;i < g_iCurLogCnt;i++)
{
if (g_Log[i].m_iFrom >= iFrom && g_Log[i].m_iTo <= iTo)
{
//找到Log
pLog = &g_Log[i];
iFondLog = 1;
break;
}
}
}
if (iFondLog == 1)
{
//在有记录的情况下,cSum = 左边结果 XOR 记录结果 XOR 右边结果
cLogResult = pLog->m_cResult;
//左边已经找过,设第三个参数为0
cLeftResult = GetCheckSum(iFrom,pLog->m_iFrom-1,0);
cRightResult = GetCheckSum(pLog->m_iTo+1,iTo,1);
cSum = cLogResult^cLeftResult^cRightResult;
}
else
{
for (i = iFrom+1;i <= iTo;i++)
{
cSum ^= g_Data[i];
}
g_Log[g_iCurLogCnt].m_iFrom = iFrom;
g_Log[g_iCurLogCnt].m_iTo = iTo;
g_Log[g_iCurLogCnt].m_cResult = cSum;
g_iCurLogCnt++;
}
return cSum;
}