?? rs232.cpp
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////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232 ////
//// ////
//// Author: MonkeyKing Aug 31th, 2003 ////
//// ////
////////////////////////////////////////////////////////////////////////////////
#include <windows.h>
class RS232 {
public:
RS232( void );
RS232( LPCSTR lpszPortNum );
~RS232();
// For more definitions see <winbase.h>
int open( LPCSTR lpszPortNum = "com1", // 串口號
DWORD dwBaudRate = CBR_9600, // 波特率
BYTE byParity = NOPARITY, // 奇偶校驗
BYTE byStopBits = ONESTOPBIT,// 停止位個數(shù)
BYTE byByteSize = 8 ); // 字節(jié)長度
DWORD output( LPCVOID pdata, DWORD len );
DWORD input( LPVOID pdest, DWORD len, DWORD dwMaxWait = 500 );
LPSTR GetErrorMessage( void );
void close();
private:
VOID ErrorToString( LPCSTR lpszMessage );
BOOL IsNT( void );
TCHAR m_lpszErrorMessage[256];
HANDLE m_hCom; // 串口句柄
OVERLAPPED m_ov; // 包含異步輸入輸出操作信息的結(jié)構(gòu)
};
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::RS232() ////
//// ////
////////////////////////////////////////////////////////////////////////////////
RS232::RS232( void )
{
m_hCom = 0;
m_lpszErrorMessage[0] = '\0';
ZeroMemory(&m_ov, sizeof(m_ov));
}
RS232::RS232( LPCSTR lpszPortNum )
{
RS232::RS232();
RS232::open( lpszPortNum );
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::~RS232() ////
//// ////
////////////////////////////////////////////////////////////////////////////////
RS232::~RS232() {
close();
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::GetErrorMessage ////
//// ////
////////////////////////////////////////////////////////////////////////////////
LPSTR RS232::GetErrorMessage( void ) {
return m_lpszErrorMessage;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::open( ) ////
//// ////
////////////////////////////////////////////////////////////////////////////////
int RS232::open( LPCSTR lpszPortNum,
DWORD dwBaudRate,
BYTE byParity,
BYTE byStopBits,
BYTE byByteSize ) {
DCB dcb; //串口設備控制塊 Device Control Block
BOOL bSuccess;
// m_hCom即為函數(shù)返回的串口的句柄
m_hCom = CreateFile( lpszPortNum, // pointer to name of the file
GENERIC_READ|GENERIC_WRITE, // 允許讀寫。
0, // 通訊設備必須以獨占方式打開。
NULL, // 無安全屬性，表示該串口不可
// 被子程序繼承。
OPEN_EXISTING, // 通訊設備已存在。
FILE_FLAG_OVERLAPPED, // 使用異步方式 overlapped I/O。
NULL); // 通訊設備不能用模板打開。
if ( m_hCom == INVALID_HANDLE_VALUE ) {
RS232::ErrorToString("RS232::open() CreateFile() failed, invalid handle value");
return FALSE;
}
// 與串口相關的參數(shù)非常多，當需要設置串口參數(shù)時，通常是先取得串口
// 的參數(shù)結(jié)構(gòu)，修改部分參數(shù)后再將參數(shù)結(jié)構(gòu)寫入
bSuccess = GetCommState(m_hCom, &dcb);
if ( !bSuccess ) {
RS232::close();
RS232::ErrorToString("RS232::open() GetCommState() failed");
return FALSE;
}
dcb.BaudRate = dwBaudRate; // 串口波特率。
dcb.Parity = byParity; // 校驗方式，值0~4分別對應無校驗、奇
// 校驗、偶校驗、校驗、置位、校驗清零。
dcb.fParity = 0; // 為1的話激活奇偶校驗檢查。
dcb.ByteSize = byByteSize; // 一個字節(jié)的數(shù)據(jù)位個數(shù)，范圍是5~8。
dcb.StopBits = byStopBits; // 停止位個數(shù)，0~2分別對應1位、1.5位、
// 2位停止位。
if ( !bSuccess ) {
RS232::close();
RS232::ErrorToString("RS232::open() SetCommState() failed");
return FALSE;
}
return TRUE;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::output() ////
//// ////
////////////////////////////////////////////////////////////////////////////////
DWORD RS232::output( LPCVOID pdata, DWORD len ) {
BOOL bSuccess;
DWORD written = 0;
if ( len < 1 )
return 0;
// create event for overlapped I/O
m_ov.hEvent = CreateEvent( NULL, // pointer to security attributes
FALSE, // flag for manual-reset event
FALSE, // flag for initial state
""); // pointer to event-object name
if ( m_ov.hEvent == INVALID_HANDLE_VALUE ) {
RS232::ErrorToString( "RS232::output() CreateEvent() failed" );
return -1;
}
bSuccess = WriteFile( m_hCom, // handle to file to write to
pdata, // pointer to data to write to file
len, // number of bytes to write
&written, // pointer to number of bytes written
&m_ov ); // pointer to structure needed for overlapped I/O
// 如果函數(shù)執(zhí)行成功的話檢查written的值為寫入的字節(jié)數(shù)，WriteFile函數(shù)執(zhí)行完畢后
// 自行填充的，利用此變量的填充值可以用來檢查該函數(shù)是否將所有的數(shù)據(jù)成功寫入串口
if ( RS232::IsNT() ) {
bSuccess = GetOverlappedResult( m_hCom, &m_ov, &written, TRUE );
if ( !bSuccess ) {
CloseHandle( m_ov.hEvent );
RS232::ErrorToString( "RS232::output() GetOverlappedResult() failed" );
return -1;
}
}
else if ( len != written ) {
CloseHandle( m_ov.hEvent );
RS232::ErrorToString( "RS232::output() WriteFile() failed" );
return -1;
}
CloseHandle( m_ov.hEvent );
return written;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::input() ////
//// ////
////////////////////////////////////////////////////////////////////////////////
DWORD RS232::input( LPVOID pdest, DWORD len, DWORD dwMaxWait ) {
BOOL bSuccess;
DWORD result = 0,
read = 0, // num read bytes
mask = 0; // a 32-bit variable that receives a mask
// indicating the type of event that occurred
if ( len < 1 )
return(0);
// create event for overlapped I/O
m_ov.hEvent = CreateEvent( NULL, // pointer to security attributes
FALSE, // flag for manual-reset event
FALSE, // flag for initial state
"" ); // pointer to event-object name
if ( m_ov.hEvent == INVALID_HANDLE_VALUE ) {
RS232::ErrorToString( "RS232::input() CreateEvent() failed" );
return -1;
}
// Specify here the event to be enabled
bSuccess = SetCommMask( m_hCom, EV_RXCHAR );
if ( ! bSuccess ) {
CloseHandle(m_ov.hEvent);
RS232::ErrorToString("RS232::input() SetCommMask() failed");
return -1;
}
// WaitForSingleObject
bSuccess = WaitCommEvent(m_hCom, &mask, &m_ov);
if ( !bSuccess ) {
int err = GetLastError();
if ( err == ERROR_IO_PENDING ) {
result = WaitForSingleObject(m_ov.hEvent, dwMaxWait); //wait dwMaxWait
// milli seconds before returning
if ( result == WAIT_FAILED ) {
CloseHandle(m_ov.hEvent);
RS232::ErrorToString( "RS232::input() WaitForSingleObject() failed" );
return -1;
}
}
}
// The specified event occured?
if ( mask & EV_RXCHAR )
{
bSuccess = ReadFile( m_hCom, // handle of file to read
pdest, // address of buffer that receives data
len, // number of bytes to read
&read, // address of number of bytes read
&m_ov); // address of structure for data
if ( RS232::IsNT() ) {
bSuccess = GetOverlappedResult(m_hCom, &m_ov, &read, TRUE);
if ( !bSuccess ) {
CloseHandle( m_ov.hEvent );
RS232::ErrorToString( "RS232::input() GetOverlappedResult() failed" );
return -1;
}
}
else if ( !bSuccess ) {
CloseHandle(m_ov.hEvent);
RS232::ErrorToString( "RS232::input() ReadFile() failed" );
return -1;
}
}
else {
CloseHandle(m_ov.hEvent);
wsprintf( m_lpszErrorMessage, "RS232::input() No EV_RXCHAR occured\n" );
return -1;
}
CloseHandle(m_ov.hEvent);
return read;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::Close() ////
//// ////
////////////////////////////////////////////////////////////////////////////////
void RS232::close( void ) {
if ( m_hCom > 0 )
CloseHandle( m_hCom );
m_hCom = 0;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::IsNT ////
//// ////
////////////////////////////////////////////////////////////////////////////////
VOID RS232::ErrorToString( LPCSTR lpszMessage ) {
LPVOID lpMessageBuffer;
DWORD error = GetLastError();
FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM, // source and processing options
NULL, // pointer to message source
error, // requested message identifie
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // the user default language.
( LPTSTR ) &lpMessageBuffer, // pointer to message buffer
0, // maximum size of message buffer
NULL); // address of array of message inserts
// and copy it in our error string
wsprintf(m_lpszErrorMessage,"%s: (%d) %s\n", lpszMessage, error, lpMessageBuffer);
LocalFree(lpMessageBuffer);
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// RS232::IsNT ////
//// ////
////////////////////////////////////////////////////////////////////////////////
BOOL RS232::IsNT( void ) {
OSVERSIONINFO osvi;
osvi.dwOSVersionInfoSize = sizeof( OSVERSIONINFO );
GetVersionEx( &osvi );
if ( osvi.dwPlatformId == VER_PLATFORM_WIN32_NT )
return TRUE;
else
return FALSE;
}
////////////////////////////////////////////////////////////////////////////////
//// ////
//// The End of RS232 ////
//// ////
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