int RTFileData::GetData(tagFileResponse * stResponse, char * buf, int & buflen, tagGetDataParam * pParam)
{
unsigned long nsize, ret, readsize, rret;
int i;
int recordsize;
char * buf1 = buf;
unsigned long stDateTime;
int roffset;
MFile stFile;
MDateTime stTmpTime;
stResponse->nFlag = 0;
//从文件中获得数据
if(stFile.OpenRead(pParam->Name) != 1)
{
return FLAG_NO_FILE;
}
if(stFile.LockFile(0, stFile.GetFileLength()) != 1)
{
return FLAG_SERVER_RETRY;
}
pParam->stCreateTime = stFile.GetCreateDateTime();
pParam->nFileSize = stFile.GetFileLength();
stTmpTime = stFile.GetUpdateDateTime();
if(stTmpTime > pParam->stUpdateTime)
{
pParam->stUpdateTime = stTmpTime;
if(!pParam->inCall)
{
stFile.UnLockFile(0, stFile.GetFileLength());
return FLAG_CHANGED;
}
}
pParam->stUpdateTime = stTmpTime;
switch(pParam->updatemode)
{
case UPDATEMODE_DBF:
if(stResponse->stOffsetTime != -1)
{
ret = pParam->Dbf.GetData(stResponse, buf, buflen, pParam->inCall, &stFile);
if(ret < 0)
{
return ret;
}
else
break;
}
case UPDATEMODE_RECORD:
if(stResponse->stOffsetTime != -1)
{
recordsize = pParam->recordsize;
if(pParam->inCall)
{
roffset = pParam->fileheadsize;
i = (pParam->nFileSize - pParam->fileheadsize) / recordsize;
if(i > (buflen / recordsize))
roffset = pParam->fileheadsize + (i - (buflen / recordsize)) * recordsize;
stFile.Seek(roffset, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
memset(&stResponse->stOffsetTime, 0, sizeof(stResponse->stOffsetTime));
memcpy(&stResponse->stOffsetTime, &stDateTime, 4);
}
else
{
roffset = stResponse->nOffset;
if(roffset != -1)
{
stFile.Seek(roffset, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
roffset = -1;
}
if(RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
if(roffset >= pParam->fileheadsize + recordsize)
{
stFile.Seek(roffset - recordsize, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
roffset = -1;
}
if(*(unsigned long *)&stDateTime != *(unsigned long *)&stResponse->stOffsetTime)
{
roffset = -1;
}
}
else
{
roffset = -1;
}
}
else
{
roffset = -1;
}
}
if(roffset == -1)//无效的偏移量，需要计算偏移, 采用2分法查找。
{//返回大于指定日期的
int offset1, offset2;
offset1 = 0;
//begin lufubo add 20131008 for只包含文件头时更新失败
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
//end lufubo add 20131008 for只包含文件头时更新失败
offset2 = ((pParam->nFileSize - pParam->fileheadsize) / recordsize) - 1;
stFile.Seek(pParam->fileheadsize, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
if(RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
roffset = pParam->fileheadsize;
}
else
{
stFile.Seek(pParam->nFileSize - ((pParam->nFileSize - pParam->fileheadsize) % recordsize) - recordsize, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
if(!RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
roffset = pParam->nFileSize - ((pParam->nFileSize - pParam->fileheadsize) % recordsize);
}
else
{
while(1)
{
roffset = (offset1 + offset2)/2 * recordsize + pParam->fileheadsize;
stFile.Seek(roffset, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
if(RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
roffset -= recordsize;
stFile.Seek(roffset, 0);
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
if(!RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
roffset += recordsize;
break;
}
else
{
offset2 = (offset1 + offset2)/2;
}
}
else if(RTFile::IsNewer(&stResponse->stOffsetTime, &stDateTime))
{
roffset += recordsize;
stFile.Seek(roffset, 0);
//返回大于指定日期的
if(stFile.Read((char*)&stDateTime, 4) != 4)
{
return FLAG_FILE_ERROR;
}
if(RTFile::IsNewer(&stDateTime, &stResponse->stOffsetTime))
{
break;
}
else if(RTFile::IsNewer(&stResponse->stOffsetTime, &stDateTime))
{
offset1 = (offset1 + offset2)/2;
}
else
{
roffset += recordsize;
break;
}
}
else
{
roffset += recordsize;
break;
}
//if(offset1 == (offset1 + recordsize) / 2)
if(offset1 >= offset2)
{
return FLAG_FILE_ERROR;
}
}
}
}
stResponse->nOffset = roffset;
}
}
nsize = (buflen / recordsize) * recordsize;
if(pParam->nFileSize - roffset <= nsize)
{
nsize = pParam->nFileSize - roffset;
stResponse->nFlag |= FLAG_LAST_PACKET;
}
stFile.Seek(roffset, 0);
readsize = 0;
while(readsize < nsize){
rret = stFile.Read(buf1, nsize - readsize);
if(rret <= 0){
stResponse->nFlag |= FLAG_LAST_PACKET;
break;
}
readsize += rret;
buf1 += rret;
}
buflen = nsize;
stResponse->nNextOffset = stResponse->nOffset + nsize;
memset(&stResponse->stNextDateTime, 0, sizeof(stResponse->stNextDateTime));
memcpy(&stResponse->stNextDateTime, &buf[nsize - recordsize], 4);
break;
}
case UPDATEMODE_FILE:
nsize = buflen;
if(pParam->nFileSize - stResponse->nOffset <= nsize)
{
nsize = pParam->nFileSize - stResponse->nOffset;
stResponse->nFlag |= FLAG_LAST_PACKET;
}
stFile.Seek(stResponse->nOffset, 0);
readsize = 0;
while(readsize < nsize){
rret = stFile.Read(buf1, nsize - readsize);
if(rret <= 0){
stResponse->nFlag |= FLAG_LAST_PACKET;
break;
}
readsize += rret;
buf1 += rret;
}
buflen = nsize;
stResponse->nNextOffset = stResponse->nOffset + readsize;
stResponse->stNextDateTime = stResponse->stOffsetTime;
break;
default:
return FLAG_SERVER_ERROR;
}
stFile.UnLockFile(0, stFile.GetFileLength());
return stResponse->nFlag;
}
