C++切割文件

1void CFileCutter::DoSplit()
2{
3    int nCompleted = 0;   //计数
4    CString strSourceFile = m_strSource;  //取得全局变量赋值给局部变量，方便操作
5    CString strDestDir = m_strDest;
6    CFile sourceFile, destFile;
7    //打开文件
8    BOOL bOK = sourceFile.Open(strSourceFile, CFile::modeRead | CFile::shareDenyWrite | CFile::typeBinary);
9    if (!bOK)//打不开就报错退出
10    {
11        ::PostMessage(m_hWndNotify, WM_CUTTERSTOP, exitSourceErr, nCompleted);
12        return;
13    }
14    int nPos = 0;
15    //逐层创建文件夹（不存在就创建）
16    while ((nPos = strDestDir.Find('\\', nPos + 1)) != -1)//少了个括号
17    {
18        ::CreateDirectory(strDestDir.Left(nPos),NULL);
19    }
20    ::CreateDirectory(strDestDir, NULL);  //创建最底层文件夹
21    if (strDestDir.Right(1) != '\\')   
22    {
23        strDestDir += '\\';
24    }
25    int nTotalFiles = sourceFile.GetLength() / m_uFileSize + 1;//判断切割后文件数
26    ::PostMessage(m_hWndNotify,WM_CUTTERSTART,nTotalFiles,TRUE); //设置进度条长度
27    const int c_page = 4 * 1024;  //每次读取大小
28    char buff[c_page]; //缓冲区
29    DWORD dwRead;
30
31    CString sDestName;
32    int nPreCount = 1;
33    UINT uWriteBytes;
34
35    do 
36    {
37        //设置文件名并创建文件
38        sDestName.Format(TEXT("%d_"), nPreCount);
39        sDestName += sourceFile.GetFileName();
40        if (!destFile.Open(strDestDir + sDestName, CFile::modeWrite | CFile::modeCreate))
41        {
42            PostMessage(m_hWndNotify, WM_CUTTERSTOP, exitDestErr, nCompleted);
43            sourceFile.Close();
44            return;
45        }
46        uWriteBytes = 0;
47        do
48        {
49            //读写操作
50            if (!m_bContinue)  //stopCutter函数
51            {
52                destFile.Close();
53                sourceFile.Close();
54                if (!m_bExitThread)  //析构函数
55                {
56                    ::PostMessage(m_hWndNotify, WM_CUTTERSTOP, exitUserForce, nCompleted);
57                }
58                return;
59            }
60            dwRead = sourceFile.Read(buff, c_page);//读
61            destFile.Write(buff, dwRead); //写
62            uWriteBytes += dwRead;  //计数
63
64        } while (dwRead > 0 && uWriteBytes < m_uFileSize);//读出了数据并且一共写的数据量小于用户要求的数据量
65        destFile.Close();    //当前文件写完了，关闭
66        nCompleted = nPreCount++;  //计数
67        ::PostMessage(m_hWndNotify, WM_CUTTERSTATUS, 0, nCompleted);
68
69    } while (dwRead > 0); //只要读出了数据就循环继续，直到源文件全部读出。
70    sourceFile.Close(); //最后关闭原文件
71    ::PostMessage(m_hWndNotify, WM_CUTTERSTOP, exitSuccess, nCompleted);
72}