Legacy Dos Header Check

//http://waleedassar.blogspot.com
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    HANDLE h=CreateFile(buffer,GENERIC_READ,FILE_SHARE_READ|FILE_SHARE_WRITE,0,OPEN_EXISTING,0,0);
    if(h==INVALID_HANDLE_VALUE) return false;
    unsigned long FileSize=GetFileSize(h,0);
    if(FileSize<0x40)
    {
                  CloseHandle(h);
          return false;
    }
        unsigned long DOSFileSize=0;
        IMAGE_DOS_HEADER DOS={0};
    unsigned long read;
    ReadFile(h,&DOS,0x40,&read,0);
        IMAGE_DOS_HEADER* pDos=&DOS;
    if(pDos->e_cblp==0)        DOSFileSize=(pDos->e_cp)*512;
        else                       DOSFileSize= ((pDos->e_cp-1)*512)+pDos->e_cblp;
    if(FileSize<DOSFileSize)
    {
        CloseHandle(h);
        return false;
    }
    if(pDos->e_lfarlc>DOSFileSize)
    {
        CloseHandle(h);
        return false;
    }
    CloseHandle(h);
    return true;