文件问题．．．谢．．．

[gxh2004]

我用一个文件来接收数据包．每个数据包有包号，我想客观做：把文件前５１２Ｋ划出来存包号．然后后面就用来依次存数据，在每次收到数据包后都要读前５１２Ｋ改存在里面的包号．然后在后面存数据．要用到哪几个函数？怎么做？

[gxh2004]

就是怎么把数据和包号写进文件

[yo_jo]

用read()加上memcpy()完全可以实现你的需求

bool CControlSDT::ReadSDTFILE()
{
/*
*********************************************************************
* 函数说明：从硬盘记录的sdt文件中提取相关数据
* 将这些数据赋给相应的结构体
* 输 入 值：strEdition -> 记录文件的版本号
* Channel_ID -> 通道号
* pbData -> 缓存的数据
* lDataLength -> 数据长度
* ltime -> 记录开始的时间
* 输 出 值：
* 返 回 值：bool型，操作是否成功
* 编 写 人：yo_jo
* 创建时间：2004-10-20 pm
*********************************************************************
*/

try
{
// 打开文件
CFile f((LPCTSTR)m_strFileName, CFile::modeRead);

// 定义一个内存块，并将文件内容读出后保存在这个内存块中
BYTE* pt = new BYTE[m_lFileSize];

f.Read(pt, m_lFileSize);

// 构造各个文件结构体变量的内容
long lTmp=0;
CString strTmp;
int iSaveYear, iSaveMonth, iSaveDay, iSaveHour, iSaveMin, iSaveSec;

// 构造[文件头]结构体
memcpy(&m_FileHeadInfo, pt+lTmp, sizeof(struct _HEAD_SDTFILE));
lTmp += (long)sizeof(struct _HEAD_SDTFILE);

FILEHEAD_strType = unchar2string(m_FileHeadInfo.cType, 16);
// <-- 在此处加上文件的判断
// 是speechdata文件才继续读取，不是则提示并返回
if (FILEHEAD_strType != "HJ08A-SpeechData")
{
AfxMessageBox("文件的格式不正确，读取文件失败！");
return false;
}
strTmp = unchar2string(m_FileHeadInfo.cChangeTime, 16);
iSaveYear = atoi(strTmp.Mid(0,4));
iSaveMonth = atoi(strTmp.Mid(4,2));
iSaveDay = atoi(strTmp.Mid(6,2));
iSaveHour = atoi(strTmp.Mid(9,2));
iSaveMin = atoi(strTmp.Mid(11,2));
iSaveSec = atoi(strTmp.Mid(13,2));
FILEHEAD_tmSaveTime = CTime(iSaveYear, iSaveMonth, iSaveDay, iSaveHour, iSaveMin, iSaveSec);
FILEHEAD_strEdition = unchar2string(m_FileHeadInfo.cEditonNo, 6);
strTmp = unchar2string(m_FileHeadInfo.cStartEndTime, 32);
iSaveYear = atoi(strTmp.Mid(0,4));
iSaveMonth = atoi(strTmp.Mid(4,2));
iSaveDay = atoi(strTmp.Mid(6,2));
iSaveHour = atoi(strTmp.Mid(9,2));
iSaveMin = atoi(strTmp.Mid(11,2));
iSaveSec = atoi(strTmp.Mid(13,2));
FILEHEAD_tmStartTime = CTime(iSaveYear, iSaveMonth, iSaveDay, iSaveHour, iSaveMin, iSaveSec);
iSaveYear = atoi(strTmp.Mid(16,4));
iSaveMonth = atoi(strTmp.Mid(20,2));
iSaveDay = atoi(strTmp.Mid(22,2));
iSaveHour = atoi(strTmp.Mid(25,2));
iSaveMin = atoi(strTmp.Mid(27,2));
iSaveSec = atoi(strTmp.Mid(29,2));
FILEHEAD_tmEndTime = CTime(iSaveYear, iSaveMonth, iSaveDay, iSaveHour, iSaveMin, iSaveSec);
FILEHEAD_uiDataAddress = (unsigned int)unchar2int(m_FileHeadInfo.cDataAdd, 6);
FILEHEAD_strTrainNo = unchar2string(m_FileHeadInfo.cTrainNo, 4);

// 构造[数据头]结构体
memcpy(&m_DataHeadInfo[0], pt+lTmp, sizeof(struct _HEAD_SDTDATA));
lTmp += (long)sizeof(struct _HEAD_SDTDATA);

DATAHEAD_uiChannelNo = (unsigned int)unchar2int(m_DataHeadInfo[0].cChannelNo, 2);
strTmp = unchar2string(m_DataHeadInfo[0].cSaveTime, 16);
iSaveYear = atoi(strTmp.Mid(0,4));
iSaveMonth = atoi(strTmp.Mid(4,2));
iSaveDay = atoi(strTmp.Mid(6,2));
iSaveHour = atoi(strTmp.Mid(9,2));
iSaveMin = atoi(strTmp.Mid(11,2));
iSaveSec = atoi(strTmp.Mid(13,2));
DATAHEAD_tmSaveTime = CTime(iSaveYear, iSaveMonth, iSaveDay, iSaveHour, iSaveMin, iSaveSec);
DATAHEAD_ulDataLength = (unsigned long)unchar2int(m_DataHeadInfo[0].cDataLength, 8);

// 构造[数据部分]结构体
DATADETAIL_ulLength = DATAHEAD_ulDataLength;
DATADETAIL_pbData = new BYTE[DATADETAIL_ulLength];

memcpy(DATADETAIL_pbData, pt+lTmp, DATADETAIL_ulLength);
lTmp += (long)DATADETAIL_ulLength;


// 构造[数据尾]结构体
memcpy(&m_DataTailInfo[0], pt+lTmp, sizeof(struct _TAIL_SDTDATA));
lTmp += (long)sizeof(struct _TAIL_SDTDATA);

DATATAIL_strEnd = unchar2string(m_DataTailInfo[0].cEnd, 3);
if (DATATAIL_strEnd != ".ND")
{
AfxMessageBox("文件尾验证失败，读取文件失败！");
delete []pt;
return false;
}

// 构造结束，释放pt
delete []pt;
return true;
}
catch (CFileException *e) // 捕捉错误
{
e->ReportError();
e->Delete();

return false;
}
}

[fallhunter]

up

是问什么函数啊，接收？读写文件？