写日志类 vs2010 日志文件按月，每月写一个日志文件

#pragma once
class LogFile
{
protected:
    CRITICAL_SECTION _csLock;
    char * _szFileName;
    HANDLE _hFile;
    bool OpenFile();//打开文件， 指针到文件尾
    DWORD Write(LPCVOID lpBuffer, DWORD dwLength);
    virtual void WriteLog( LPCVOID lpBuffer, DWORD dwLength);//写日志, 可以扩展修改
    void Lock()  {::EnterCriticalSection(&_csLock); }
    void Unlock() {::LeaveCriticalSection(&_csLock);}
    char szFileSuffix[32]; //文件后缀
public:
    LogFile(char*szFileName);
    virtual ~LogFile();
    const char * GetFileName()
    {
        return _szFileName;
    }

    void SetFileName(const char *szName);//修改文件名， 同时关闭上一个日志文件
    bool IsOpen()
    {
        return _hFile != INVALID_HANDLE_VALUE;
    }

    void Close();
    void Log(LPCVOID lpBuffer, DWORD dwLength);//追加日志内容
    void Log(const char *szText){
        Log(szText, strlen(szText));}
    void Log(CString str);
    void Log(TCHAR *buffer);
private://屏蔽函数
    LogFile(const LogFile&);
    LogFile&operator = (const LogFile&);
};

#include "StdAfx.h"
#include "LogFile.h"

LogFile::LogFile(char*szFileNameParam)
{
    memset(szFileSuffix,0,sizeof(szFileSuffix));
    strcat_s(szFileSuffix,szFileNameParam);  //文件后辍，不带日期
    _szFileName = NULL;
    _hFile = INVALID_HANDLE_VALUE;
    ::InitializeCriticalSection(&_csLock);

    //求出当前日期
    time_t now;
    time(&now);
    char szCurDate[256] = {0};
    struct tm newtime;
    localtime_s(&newtime,&now);
    strftime(szCurDate,19,"%Y%m",&newtime);

    char szFileName[64] = {0};
    strcat_s(szFileName,10,szCurDate); //日期在前面
    strcat_s(szFileName,szFileSuffix);  //追加文件名
    SetFileName(szFileName);
}

//-------------------------------------------------------------------------
LogFile::~LogFile()
{
    ::DeleteCriticalSection(&_csLock);
    Close();
    if(_szFileName)
        delete [] _szFileName;
}
//-------------------------------------------------------------------------
bool LogFile::OpenFile()
{
    if(IsOpen())
        return true;
    if(!_szFileName)
        return false;

    _hFile = CreateFileA(
        _szFileName,
        GENERIC_WRITE,
        FILE_SHARE_READ | FILE_SHARE_WRITE,
        NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        NULL);

    if(!IsOpen() && GetLastError() == 2)//打开不成功， 且因为文件不存在， 创建文件
        _hFile = CreateFileA(
        _szFileName,
        GENERIC_WRITE,
        FILE_SHARE_READ | FILE_SHARE_WRITE,
        NULL,
        OPEN_ALWAYS,
        FILE_ATTRIBUTE_NORMAL,
        NULL);

    if(IsOpen())
        SetFilePointer(_hFile, 0, NULL, FILE_END);
    return IsOpen();
}
//-------------------------------------------------------------------------
DWORD LogFile::Write(LPCVOID lpBuffer, DWORD dwLength)
{
    DWORD dwWriteLength = 0;
    if(IsOpen())
        WriteFile(_hFile, lpBuffer, dwLength, &dwWriteLength, NULL);
    return dwWriteLength;
}
//-------------------------------------------------------------------------
void LogFile::WriteLog( LPCVOID lpBuffer, DWORD dwLength)
{
    DWORD dwWriteLength;
    char buf[1024]={0};
    strcat_s(buf,1000,(char*)lpBuffer);
    if(IsOpen())
    {
        time_t now;
        time(&now);
        char temp[1024];
        struct tm newtime;
        localtime_s(&newtime,&now);
        memset(temp,0,sizeof(temp));
        strftime(temp, 64, "%Y-%m-%d %H:%M:%S   :", &newtime);
        strcat_s(temp,128,"   :");
        strcat_s(temp,1024,buf);
        WriteFile(_hFile, temp,strlen(temp), &dwWriteLength, NULL);
        WriteFile(_hFile, "\r\n",2, &dwWriteLength, NULL);
        FlushFileBuffers(_hFile); //存硬盘

    }
    else
    {
        ;
    }
}
//-------------------------------------------------------------------------
void LogFile::SetFileName(const char *szName)
{
    //assert(szName);

    if(_szFileName != NULL)
    {
        //AfxMessageBox(_T("_szFileName is NULL"));
        delete []_szFileName;
    }
    Close();
    int len = strlen(szName);
    _szFileName = new char[32];
//    assert(_szFileName);
    strcpy_s(_szFileName,30,szName);
}
//-------------------------------------------------------------------------
void LogFile::Close()
{
    if(IsOpen())
    {
        CloseHandle(_hFile);
        _hFile = INVALID_HANDLE_VALUE;
    }
}
//-------------------------------------------------------------------------
void LogFile::Log(LPCVOID lpBuffer, DWORD dwLength)
{
//    assert(lpBuffer);
    __try
    {
        Lock();

        //算出现在应该写日志的文件名
        time_t now;
        time(&now);
        char szCurDate[256] = {0};
        struct tm newtime;
        localtime_s(&newtime,&now);
        strftime(szCurDate,19,"%Y%m",&newtime);
        char szCurFileName[64] = {0};
        strcat_s(szCurFileName,10,szCurDate); //日期在前面
        strcat_s(szCurFileName,szFileSuffix);  //追加文件名
        if(!PathFileExistsA(szCurFileName))
            SetFileName(szCurFileName);

        if(OpenFile())
            WriteLog(lpBuffer, dwLength);
    }
    __finally
    {
        Unlock();
    }
}

void LogFile::Log(TCHAR *buffer)
{
    CT2A buf_str(buffer);
    Log(buf_str);
}
void LogFile::Log(CString str)
{
    Log(str.GetBuffer());
}