delphi编写串口程序使用串口控件spcomm，Comm1ReceiveData（）这个接收函数由什么触发？
delphi编写串口程序使用串口控件spcomm，Comm1ReceiveData（）这个接收函数由什么触发，还由一个线程来操作的？在程序中也没有这么一个线程啊！高手指点一下原函数代码如下：
procedure TFrmMain.Comm1ReceiveData(Sender: TObject; Buffer: Pointer;
BufferLength: Word);
var str :string;
begin
//Memo自动清空
if cbAutoClean.Checked and (Memo1.Lines.Count > 50) then
Memo1.Clear;
SetLength(Str,BufferLength);
move(buffer^,pchar(@Str)^,bufferlength);
if FShowText then
begin
if cbRecHex.Checked then
Memo1.Text:=Memo1.Text+StrToHexStr(Str)+' '
else
Memo1.Text := Memo1.Text + Str;
Memo1.SelStart := Length(Memo1.Text);
Memo1.SelLength:= 0;
Memo1.Perform(EM_SCROLLCARET,0,0);
end;
end; 靠.麻烦你穿上全文........就这个吊样子怎么给你看啊 unit SPComm;
//
// 硂琌梆硄癟じン, ㄑ Delphi 2.0 莱ノ祘Αㄏノ. 続ノㄓ暗穨北の
// 虏虫肚块. じン㊣ Win32 API ㄓ笷Θ┮惠, 叫ǎCommunications场
//
// じン把σ David Wann. ┮籹 COMM32.PAS Version 1.0﹍弧
// This Communications Component is implemented using separate Read and Write
// threads. Messages from the threads are posted to the Comm control which is
// an invisible window. To handle data from the comm port, simply
// attach a handler to 'OnReceiveData'. There is no need to free the memory
// buffer passed to this handler. If TAPI is used to open the comm port, some
// changes to this component are needed ('StartComm' currently opens the comm
// port). The 'OnRequestHangup' event is included to assist this.
//
// David Wann
// Stamina Software
// 28/02/96
// davidwann@hunterlink.net.au
//
//
// 硂じンЧ禣, 舧ī' э┪暗ヴㄤウノ硚. 埃虫縒砪芥じン.
// This component is totally free(copyleft), you can do anything in any
// purpose EXCEPT SELL IT ALONE.
//
//
// Author?: 睫 Small-Pig Team in Taiwan R.O.C.
// Email : spigteam@vlsi.ice.cycu.edu.tw
// Date ? : 1997/5/9
//
// Version 1.01 1996/9/4
// - Add setting Parity, Databits, StopBits
// - Add setting Flowcontrol:Dtr-Dsr, Cts-Rts, Xon-Xoff
// - Add setting Timeout information for read/write
//
// Version 1.02 1996/12/24
// - Add Sender parameter to TReceiveDataEvent
//
// Version 2.0 1997/4/15
// - Support separatly DTR/DSR and RTS/CTS hardware flow control setting
// - Support separatly OutX and InX software flow control setting
// - Log file(for debug) may used by many comms at the same time
// - Add DSR sensitivity property
// - You can set error char. replacement when parity error
// - Let XonLim/XoffLim and XonChar/XoffChar setting by yourself
// - You may change flow-control when comm is still opened
// - Change TComm32 to TComm
// - Add OnReceiveError event handler
// - Add OnReceiveError event handler when overrun, framing error,
// parity error
// - Fix some bug
//
// Version 2.01 1997/4/19
// - Support some property for modem
// - Add OnModemStateChange event hander when RLSD(CD) change state
//
// Version 2.02 1997/4/28
// - Bug fix: When receive XOFF character, the system FAULT!!!!
//
// Version 2.5 1997/5/9
// - Add OnSendDataEmpty event handler when all data in buffer
// are sent(send-buffer become empty) this handler is called.
// You may call send data here.
// - Change the ModemState parameters in OnModemStateChange
// to ModemEvent to indicate what modem event make this call
// - Add RING signal detect. When RLSD changed state or
// RING signal was detected, OnModemStateChange handler is called
// - Change XonLim and XoffLim from 100 to 500
// - Remove TWriteThread.WriteData member
// - PostHangupCall is re-design for debuging function
// - Add a boolean property SendDataEmpty, True when send buffer
// is empty
//
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
const
// messages from read/write threads
PWM_GOTCOMMDATA = WM_USER + 1;
PWM_RECEIVEERROR = WM_USER + 2;
PWM_REQUESTHANGUP = WM_USER + 3;
PWM_MODEMSTATECHANGE = WM_USER + 4;
PWM_SENDDATAEMPTY = WM_USER + 5;
type
TParity = ( None, Odd, Even, Mark, Space );
TStopBits = ( _1, _1_5, _2 );
TByteSize = ( _5, _6, _7, _8 );
TDtrControl = ( DtrEnable, DtrDisable, DtrHandshake );
TRtsControl = ( RtsEnable, RtsDisable, RtsHandshake, RtsTransmissionAvailable );
ECommsError = class( Exception );
TReceiveDataEvent = procedure(Sender: TObject; Buffer: Pointer;
BufferLength: Word) of object;
TReceiveErrorEvent = procedure(Sender: TObject; EventMask : DWORD) of object;
TModemStateChangeEvent = procedure(Sender: TObject; ModemEvent : DWORD) of object;
TSendDataEmptyEvent = procedure(Sender: TObject) of object;
const
//
// Modem Event Constant
//
ME_CTS = 1;
ME_DSR = 2;
ME_RING = 4;
ME_RLSD = 8;
type
TReadThread = class( TThread )
protected
procedure Execute; override;
public
hCommFile: THandle;
hCloseEvent: THandle;
hComm32Window: THandle;
function SetupCommEvent( lpOverlappedCommEvent: POverlapped;
var lpfdwEvtMask: DWORD ): Boolean;
function SetupReadEvent( lpOverlappedRead: POverlapped;
lpszInputBuffer: LPSTR; dwSizeofBuffer: DWORD;
var lpnNumberOfBytesRead: DWORD ): Boolean;
function HandleCommEvent( lpOverlappedCommEvent: POverlapped;
var lpfdwEvtMask: DWORD; fRetrieveEvent: Boolean ): Boolean;
function HandleReadEvent( lpOverlappedRead: POverlapped;
lpszInputBuffer: LPSTR; dwSizeofBuffer: DWORD;
var lpnNumberOfBytesRead: DWORD ): Boolean;
function HandleReadData( lpszInputBuffer: LPCSTR; dwSizeofBuffer: DWORD ): Boolean;
function ReceiveData( lpNewString: LPSTR; dwSizeofNewString: DWORD ): BOOL;
function ReceiveError( EvtMask : DWORD ): BOOL;
function ModemStateChange( ModemEvent : DWORD ) : BOOL;
procedure PostHangupCall;
end;
TWriteThread = class( TThread )
protected
procedure Execute; override;
function HandleWriteData( lpOverlappedWrite: POverlapped;
pDataToWrite: PChar; dwNumberOfBytesToWrite: DWORD): Boolean;
public
hCommFile: THandle;
hCloseEvent: THandle;
hComm32Window: THandle;
pFSendDataEmpty: ^Boolean;
procedure PostHangupCall;
end;
TComm = class( TComponent )
private
{ Private declarations }
ReadThread: TReadThread;
WriteThread: TWriteThread;
hCommFile: THandle;
hCloseEvent: THandle;
FHWnd: THandle;
FSendDataEmpty: Boolean; // True if send buffer become empty
FCommName: String;
FBaudRate: DWORD;
FParityCheck: Boolean;
FOutx_CtsFlow: Boolean;
FOutx_DsrFlow: Boolean;
FDtrControl: TDtrControl;
FDsrSensitivity: Boolean;
FTxContinueOnXoff:Boolean;
FOutx_XonXoffFlow:Boolean;
FInx_XonXoffFlow: Boolean;
FReplaceWhenParityError: Boolean;
FIgnoreNullChar: Boolean;
FRtsControl: TRtsControl;
FXonLimit: WORD;
FXoffLimit: WORD;
FByteSize: TByteSize;
FParity: TParity;
FStopBits: TStopBits;
FXonChar: AnsiChar;
FXoffChar: AnsiChar;
FReplacedChar: AnsiChar;
FReadIntervalTimeout: DWORD;
FReadTotalTimeoutMultiplier: DWORD;
FReadTotalTimeoutConstant: DWORD;
FWriteTotalTimeoutMultiplier: DWORD;
FWriteTotalTimeoutConstant: DWORD;
FOnReceiveData: TReceiveDataEvent;
FOnRequestHangup: TNotifyEvent;
FOnReceiveError: TReceiveErrorEvent;
FOnModemStateChange:TModemStateChangeEvent;
FOnSendDataEmpty: TSendDataEmptyEvent;
procedure SetBaudRate( Rate : DWORD );
procedure SetParityCheck( b : Boolean );
procedure SetOutx_CtsFlow( b : Boolean );
procedure SetOutx_DsrFlow( b : Boolean );
procedure SetDtrControl( c : TDtrControl );
procedure SetDsrSensitivity( b : Boolean );
procedure SetTxContinueOnXoff( b : Boolean );
procedure SetOutx_XonXoffFlow( b : Boolean );
procedure SetInx_XonXoffFlow( b : Boolean );
procedure SetReplaceWhenParityError( b : Boolean );
procedure SetIgnoreNullChar( b : Boolean );
procedure SetRtsControl( c : TRtsControl );
procedure SetXonLimit( Limit : WORD );
procedure SetXoffLimit( Limit : WORD );
procedure SetByteSize( Size : TByteSize );
procedure SetParity( p : TParity );
procedure SetStopBits( Bits : TStopBits );
procedure SetXonChar( c : AnsiChar );
procedure SetXoffChar( c : AnsiChar );
procedure SetReplacedChar( c : AnsiChar );
procedure SetReadIntervalTimeout( v : DWORD );
procedure SetReadTotalTimeoutMultiplier( v : DWORD );
procedure SetReadTotalTimeoutConstant( v : DWORD );
procedure SetWriteTotalTimeoutMultiplier( v : DWORD );
procedure SetWriteTotalTimeoutConstant( v : DWORD );
procedure CommWndProc( var msg: TMessage );
procedure _SetCommState;
procedure _SetCommTimeout;
protected
{ Protected declarations }
procedure CloseReadThread;
procedure CloseWriteThread;
procedure ReceiveData(Buffer: PChar; BufferLength: Word);
procedure ReceiveError( EvtMask : DWORD );
procedure ModemStateChange( ModemEvent : DWORD );
procedure RequestHangup;
procedure _SendDataEmpty;
public
{ Public declarations }
property Handle: THandle read hCommFile;
property SendDataEmpty : Boolean read FSendDataEmpty;
constructor Create( AOwner: TComponent ); override;
destructor Destroy; override;
procedure StartComm;
procedure StopComm;
function WriteCommData( pDataToWrite: PChar; dwSizeofDataToWrite: Word ): Boolean;
function GetModemState : DWORD;
published
{ Published declarations }
property CommName: String read FCommName write FCommName;
property BaudRate: DWORD read FBaudRate write SetBaudRate;
property ParityCheck: Boolean read FParityCheck write SetParityCheck;
property Outx_CtsFlow: Boolean read FOutx_CtsFlow write SetOutx_CtsFlow;
property Outx_DsrFlow: Boolean read FOutx_DsrFlow write SetOutx_DsrFlow;
property DtrControl: TDtrControl read FDtrControl write SetDtrControl;
property DsrSensitivity: Boolean read FDsrSensitivity write SetDsrSensitivity;
property TxContinueOnXoff: Boolean read FTxContinueOnXoff write SetTxContinueOnXoff;
property Outx_XonXoffFlow: Boolean read FOutx_XonXoffFlow write SetOutx_XonXoffFlow;
property Inx_XonXoffFlow: Boolean read FInx_XonXoffFlow write SetInx_XonXoffFlow;
property ReplaceWhenParityError: Boolean read FReplaceWhenParityError write SetReplaceWhenParityError;
property IgnoreNullChar: Boolean read FIgnoreNullChar write SetIgnoreNullChar;
property RtsControl: TRtsControl read FRtsControl write SetRtsControl;
property XonLimit: WORD read FXonLimit write SetXonLimit;
property XoffLimit: WORD read FXoffLimit write SetXoffLimit;
property ByteSize: TByteSize read FByteSize write SetByteSize;
property Parity: TParity read FParity write FParity;
property StopBits: TStopBits read FStopBits write SetStopBits;
property XonChar: AnsiChar read FXonChar write SetXonChar;
property XoffChar: AnsiChar read FXoffChar write SetXoffChar;
property ReplacedChar: AnsiChar read FReplacedChar write SetReplacedChar;
property ReadIntervalTimeout: DWORD read FReadIntervalTimeout write SetReadIntervalTimeout;
property ReadTotalTimeoutMultiplier: DWORDread FReadTotalTimeoutMultiplierwrite SetReadTotalTimeoutMultiplier;
property ReadTotalTimeoutConstant: DWORD read FReadTotalTimeoutConstant write SetReadTotalTimeoutConstant;
property WriteTotalTimeoutMultiplier: DWORD read FWriteTotalTimeoutMultiplier write SetWriteTotalTimeoutMultiplier;
property WriteTotalTimeoutConstant: DWORD read FWriteTotalTimeoutConstant write SetWriteTotalTimeoutConstant;
property OnReceiveData: TReceiveDataEvent
read FOnReceiveData write FOnReceiveData;
property OnReceiveError: TReceiveErrorEvent
read FOnReceiveError write FOnReceiveError;
property OnModemStateChange: TModemStateChangeEvent
read FOnModemStateChange write FOnModemStateChange;
property OnRequestHangup: TNotifyEvent
read FOnRequestHangup write FOnRequestHangup;
property OnSendDataEmpty: TSendDataEmptyEvent
read FOnSendDataEmpty write FOnSendDataEmpty;
end;
const
// This is the message posted to the WriteThread
// When we have something to write.
PWM_COMMWRITE = WM_USER+1;
// Default size of the Input Buffer used by this code.
INPUTBUFFERSIZE = 2048;
procedure Register;
implementation
(******************************************************************************)
// TComm PUBLIC METHODS
(******************************************************************************)
constructor TComm.Create( AOwner: TComponent );
begin
inherited Create( AOwner );
ReadThread := nil;
WriteThread := nil;
hCommFile := 0;
hCloseEvent := 0;
FSendDataEmpty := True;
FCommName := 'COM2';
FBaudRate := 9600;
FParityCheck := False;
FOutx_CtsFlow := False;
FOutx_DsrFlow := False;
FDtrControl := DtrEnable;
FDsrSensitivity := False;
FTxContinueOnXoff := True;
FOutx_XonXoffFlow := True;
FInx_XonXoffFlow := True;
FReplaceWhenParityError := False;
FIgnoreNullChar := False;
FRtsControl := RtsEnable;
FXonLimit := 500;
FXoffLimit := 500;
FByteSize := _8;
FParity := None;
FStopBits := _1;
FXonChar := chr($11); // Ctrl-Q
FXoffChar := chr($13); // Ctrl-S
FReplacedChar := chr(0);
FReadIntervalTimeout := 100;
FReadTotalTimeoutMultiplier:= 0;
FReadTotalTimeoutConstant := 0;
FWriteTotalTimeoutMultiplier := 0;
FWriteTotalTimeoutConstant := 0;
if not (csDesigning in ComponentState) then
FHWnd := AllocateHWnd(CommWndProc)
end;
destructor TComm.Destroy;
begin
if not (csDesigning in ComponentState) then
DeallocateHWnd(FHwnd);
inherited Destroy;
end;
//
//FUNCTION: StartComm
//
//PURPOSE: Starts communications over the comm port.
//
//PARAMETERS:
// hNewCommFile - This is the COMM File handle to communicate with.
// This handle is obtained from TAPI.
//
//Output:
// Successful: Startup the communications.
// Failure: Raise a exception
//
//COMMENTS:
//
// StartComm makes sure there isn't communication in progress already,
// creates a Comm file, and creates the read and write threads.It
// also configures the hNewCommFile for the appropriate COMM settings.
//
// If StartComm fails for any reason, it's up to the calling application
// to close the Comm file handle.
//
//
procedure TComm.StartComm;
var
hNewCommFile: THandle;
begin
// Are we already doing comm?
if (hCommFile <> 0) then
raise ECommsError.Create( 'This serial port already opened' );
hNewCommFile := CreateFile( PChar(FCommName),
GENERIC_READ or GENERIC_WRITE,
0, {not shared}
nil, {no security ??}
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL or FILE_FLAG_OVERLAPPED,
0 {template} );
if hNewCommFile = INVALID_HANDLE_VALUE then
raise ECommsError.Create( 'Error opening serial port' );
// Is this a valid comm handle?
if GetFileType( hNewCommFile ) <> FILE_TYPE_CHAR then
begin
CloseHandle( hNewCommFile );
raise ECommsError.Create( 'File handle is not a comm handle ' )
end;
if not SetupComm( hNewCommFile, 4096, 4096 ) then
begin
CloseHandle( hCommFile );
raise ECommsError.Create( 'Cannot setup comm buffer' )
end;
// It is ok to continue.
hCommFile := hNewCommFile;
// purge any information in the buffer
PurgeComm( hCommFile, PURGE_TXABORT or PURGE_RXABORT or
PURGE_TXCLEAR or PURGE_RXCLEAR ) ;
FSendDataEmpty := True;
// Setting the time-out value
_SetCommTimeout;
// Querying then setting the comm port configurations.
_SetCommState;
// Create the event that will signal the threads to close.
hCloseEvent := CreateEvent( nil, True, False, nil );
if hCloseEvent = 0 then
begin
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create event' )
end;
// Create the Read thread.
try
ReadThread := TReadThread.Create( True {suspended} );
except
ReadThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create read thread' )
end;
ReadThread.hCommFile := hCommFile;
ReadThread.hCloseEvent := hCloseEvent;
ReadThread.hComm32Window := FHWnd;
// Comm threads should have a higher base priority than the UI thread.
// If they don't, then any temporary priority boost the UI thread gains
// could cause the COMM threads to loose data.
ReadThread.Priority := tpHighest;
// Create the Write thread.
try
WriteThread := TWriteThread.Create( True {suspended} );
except
CloseReadThread;
WriteThread := nil;
CloseHandle( hCloseEvent );
CloseHandle( hCommFile );
hCommFile := 0;
raise ECommsError.Create( 'Unable to create write thread' )
end;
WriteThread.hCommFile := hCommFile;
WriteThread.hCloseEvent := hCloseEvent;
WriteThread.hComm32Window := FHWnd;
WriteThread.pFSendDataEmpty := @FSendDataEmpty;
WriteThread.Priority := tpHigher;
ReadThread.Resume;
WriteThread.Resume
// Everything was created ok.Ready to go!
end; {TComm.StartComm}
//
//FUNCTION: StopComm
//
//PURPOSE: Stop and end all communication threads.
//
//PARAMETERS:
// none
//
//RETURN VALUE:
// none
//
//COMMENTS:
//
// Tries to gracefully signal all communication threads to
// close, but terminates them if it has to.
//
//
procedure TComm.StopComm;
begin
// No need to continue if we're not communicating.
if hCommFile = 0 then
Exit;
// Close the threads.
CloseReadThread;
CloseWriteThread;
// Not needed anymore.
CloseHandle( hCloseEvent );
// Now close the comm port handle.
CloseHandle( hCommFile );
hCommFile := 0
end; {TComm.StopComm}
//
//FUNCTION: WriteCommData(PChar, Word)
//
//PURPOSE: Send a String to the Write Thread to be written to the Comm.
//
//PARAMETERS:
// pszStringToWrite - String to Write to Comm port.
// nSizeofStringToWrite - length of pszStringToWrite.
//
//RETURN VALUE:
// Returns TRUE if the PostMessage is successful.
// Returns FALSE if PostMessage fails or Write thread doesn't exist.
//
//COMMENTS:
//
// This is a wrapper function so that other modules don't care that
// Comm writing is done via PostMessage to a Write thread.Note that
// using PostMessage speeds up response to the UI (very little delay to
// 'write' a string) and provides a natural buffer if the comm is slow
// (ie: the messages just pile up in the message queue).
//
// Note that it is assumed that pszStringToWrite is allocated with
// LocalAlloc, and that if WriteCommData succeeds, its the job of the
// Write thread to LocalFree it.If WriteCommData fails, then its
// the job of the calling function to free the string.
//
//
function TComm.WriteCommData( pDataToWrite: PChar; dwSizeofDataToWrite: Word ): Boolean;
var
Buffer: Pointer;
begin
if (WriteThread <> nil) and (dwSizeofDataToWrite <> 0) then
begin
Buffer := Pointer(LocalAlloc( LPTR, dwSizeofDataToWrite+1 ));
Move( pDataToWrite^, Buffer^, dwSizeofDataToWrite );
if PostThreadMessage( WriteThread.ThreadID, PWM_COMMWRITE,
WPARAM(dwSizeofDataToWrite), LPARAM(Buffer) ) then
begin
FSendDataEmpty := False;
Result := True;
Exit
end
end;
Result := False
end; {TComm.WriteCommData}
//
//FUNCTION: GetModemState
//
//PURPOSE: Read the state of modem input pin right now
//
//PARAMETERS:
// none
//
//RETURN VALUE:
//
// A DWORD variable containing one or more of following codes:
//
// Value Meaning
// ---------------------------------------------------------------------
// MS_CTS_ON The CTS (clear-to-send) signal is on.
// MS_DSR_ON The DSR (data-set-ready) signal is on.
// MS_RING_ONThe ring indicator signal is on.
// MS_RLSD_ONThe RLSD (receive-line-signal-detect) signal is on.
//
// If this comm have bad handle or not yet opened, the return value is 0
//
//COMMENTS:
//
// This member function calls GetCommModemStatus and return its value.
// Before calling this member function, you must have a successful
// 'StartOpen' call.
//
//
function TComm.GetModemState : DWORD;
var
dwModemState : DWORD;
begin
if not GetCommModemStatus( hCommFile, dwModemState ) then
Result := 0
else
Result := dwModemState
end;
(******************************************************************************)
//TComm PROTECTED METHODS
(******************************************************************************)
//
//FUNCTION: CloseReadThread
//
//PURPOSE: Close the Read Thread.
//
//PARAMETERS:
// none
//
//RETURN VALUE:
// none
//
//COMMENTS:
//
// Closes the Read thread by signaling the CloseEvent.
// Purges any outstanding reads on the comm port.
//
// Note that terminating a thread leaks memory.
// Besides the normal leak incurred, there is an event object
// that doesn't get closed.This isn't worth worrying about
// since it shouldn't happen anyway.
//
//
procedure TComm.CloseReadThread;
begin
// If it exists...
if ReadThread <> nil then
begin
// Signal the event to close the worker threads.
SetEvent( hCloseEvent );
// Purge all outstanding reads
PurgeComm( hCommFile, PURGE_RXABORT + PURGE_RXCLEAR );
// Wait 10 seconds for it to exit.Shouldn't happen.
if (WaitForSingleObject(ReadThread.Handle, 10000) = WAIT_TIMEOUT) then
ReadThread.Terminate;
ReadThread.Free;
ReadThread := nil
end
end; {TComm.CloseReadThread}
//
//FUNCTION: CloseWriteThread
//
//PURPOSE: Closes the Write Thread.
//
//PARAMETERS:
// none
//
//RETURN VALUE:
// none
//
//COMMENTS:
//
// Closes the write thread by signaling the CloseEvent.
// Purges any outstanding writes on the comm port.
//
// Note that terminating a thread leaks memory.
// Besides the normal leak incurred, there is an event object
// that doesn't get closed.This isn't worth worrying about
// since it shouldn't happen anyway.
//
//
procedure TComm.CloseWriteThread;
begin
// If it exists...
if WriteThread <> nil then
begin
// Signal the event to close the worker threads.
SetEvent(hCloseEvent);
// Purge all outstanding writes.
PurgeComm(hCommFile, PURGE_TXABORT + PURGE_TXCLEAR);
FSendDataEmpty := True;
// Wait 10 seconds for it to exit.Shouldn't happen.
if WaitForSingleObject( WriteThread.Handle, 10000 ) = WAIT_TIMEOUT then
WriteThread.Terminate;
WriteThread.Free;
WriteThread := nil
end
end; {TComm.CloseWriteThread}
procedure TComm.ReceiveData(Buffer: PChar; BufferLength: Word);
begin
if Assigned(FOnReceiveData) then
FOnReceiveData( self, Buffer, BufferLength )
end;
procedure TComm.ReceiveError( EvtMask : DWORD );
begin
if Assigned(FOnReceiveError) then
FOnReceiveError( self, EvtMask )
end;
procedure TComm.ModemStateChange( ModemEvent : DWORD );
begin
if Assigned(FOnModemStateChange) then
FOnModemStateChange( self, ModemEvent )
end;
procedure TComm.RequestHangup;
begin
if Assigned(FOnRequestHangup) then
FOnRequestHangup( Self )
end;
procedure TComm._SendDataEmpty;
begin
if Assigned(FOnSendDataEmpty) then
FOnSendDataEmpty( self )
end;
(******************************************************************************)
//TComm PRIVATE METHODS
(******************************************************************************)
procedure TComm.CommWndProc( var msg: TMessage );
begin
case msg.msg of
PWM_GOTCOMMDATA:
begin
ReceiveData( PChar(msg.LParam), msg.WParam );
LocalFree( msg.LParam )
end;
PWM_RECEIVEERROR: ReceiveError( msg.LParam );
PWM_MODEMSTATECHANGE:ModemStateChange( msg.LParam );
PWM_REQUESTHANGUP: RequestHangup;
PWM_SENDDATAEMPTY: _SendDataEmpty
end
end;
procedure TComm._SetCommState;
var
dcb: Tdcb;
commprop: TCommProp;
fdwEvtMask: DWORD;
begin
// Configure the comm settings.
// NOTE: Most Comm settings can be set through TAPI, but this means that
// the CommFile will have to be passed to this component.
GetCommState( hCommFile, dcb );
GetCommProperties( hCommFile, commprop );
GetCommMask( hCommFile, fdwEvtMask );
// fAbortOnError is the only DCB dependancy in TapiComm.
// Can't guarentee that the SP will set this to what we expect.
{dcb.fAbortOnError := False; NOT VALID}
dcb.BaudRate := FBaudRate;
dcb.Flags := 1; // Enable fBinary
if FParityCheck then
dcb.Flags := dcb.Flags or 2; // Enable parity check
// setup hardware flow control
if FOutx_CtsFlow then
dcb.Flags := dcb.Flags or 4;
if FOutx_DsrFlow then
dcb.Flags := dcb.Flags or 8;
if FDtrControl = DtrEnable then
dcb.Flags := dcb.Flags or $10
else if FDtrControl = DtrHandshake then
dcb.Flags := dcb.Flags or $20;
if FDsrSensitivity then
dcb.Flags := dcb.Flags or $40;
if FTxContinueOnXoff then
dcb.Flags := dcb.Flags or $80;
if FOutx_XonXoffFlow then
dcb.Flags := dcb.Flags or $100;
if FInx_XonXoffFlow then
dcb.Flags := dcb.Flags or $200;
if FReplaceWhenParityError then
dcb.Flags := dcb.Flags or $400;
if FIgnoreNullChar then
dcb.Flags := dcb.Flags or $800;
if FRtsControl = RtsEnable then
dcb.Flags := dcb.Flags or $1000
else if FRtsControl = RtsHandshake then
dcb.Flags := dcb.Flags or $2000
else if FRtsControl = RtsTransmissionAvailable then
dcb.Flags := dcb.Flags or $3000;
dcb.XonLim := FXonLimit;
dcb.XoffLim := FXoffLimit;
dcb.ByteSize := Ord( FByteSize ) + 5;
dcb.Parity := Ord( FParity );
dcb.StopBits := Ord( FStopBits );
dcb.XonChar := FXonChar;
dcb.XoffChar := FXoffChar;
dcb.ErrorChar := FReplacedChar;
SetCommState( hCommFile, dcb )
end;
procedure TComm._SetCommTimeout;
var
commtimeouts: TCommTimeouts;
begin
GetCommTimeouts( hCommFile, commtimeouts );
// The CommTimeout numbers will very likely change if you are
// coding to meet some kind of specification where
// you need to reply within a certain amount of time after
// recieving the last byte.However,If 1/4th of a second
// goes by between recieving two characters, its a good
// indication that the transmitting end has finished, even
// assuming a 1200 baud modem.
commtimeouts.ReadIntervalTimeout := FReadIntervalTimeout;
commtimeouts.ReadTotalTimeoutMultiplier:= FReadTotalTimeoutMultiplier;
commtimeouts.ReadTotalTimeoutConstant := FReadTotalTimeoutConstant;
commtimeouts.WriteTotalTimeoutMultiplier := FWriteTotalTimeoutMultiplier;
commtimeouts.WriteTotalTimeoutConstant := FWriteTotalTimeoutConstant;
SetCommTimeouts( hCommFile, commtimeouts );
end;
procedure TComm.SetBaudRate( Rate : DWORD );
begin
if Rate = FBaudRate then
Exit;
FBaudRate := Rate;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetParityCheck( b : Boolean );
begin
if b = FParityCheck then
Exit;
FParityCheck := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetOutx_CtsFlow( b : Boolean );
begin
if b = FOutx_CtsFlow then
Exit;
FOutx_CtsFlow := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetOutx_DsrFlow( b : Boolean );
begin
if b = FOutx_DsrFlow then
Exit;
FOutx_DsrFlow := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetDtrControl( c : TDtrControl );
begin
if c = FDtrControl then
Exit;
FDtrControl := c;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetDsrSensitivity( b : Boolean );
begin
if b = FDsrSensitivity then
Exit;
FDsrSensitivity := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetTxContinueOnXoff( b : Boolean );
begin
if b = FTxContinueOnXoff then
Exit;
FTxContinueOnXoff := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetOutx_XonXoffFlow( b : Boolean );
begin
if b = FOutx_XonXoffFlow then
Exit;
FOutx_XonXoffFlow := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetInx_XonXoffFlow( b : Boolean );
begin
if b = FInx_XonXoffFlow then
Exit;
FInx_XonXoffFlow := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetReplaceWhenParityError( b : Boolean );
begin
if b = FReplaceWhenParityError then
Exit;
FReplaceWhenParityError := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetIgnoreNullChar( b : Boolean );
begin
if b = FIgnoreNullChar then
Exit;
FIgnoreNullChar := b;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetRtsControl( c : TRtsControl );
begin
if c = FRtsControl then
Exit;
FRtsControl := c;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetXonLimit( Limit : WORD );
begin
if Limit = FXonLimit then
Exit;
FXonLimit := Limit;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetXoffLimit( Limit : WORD );
begin
if Limit = FXoffLimit then
Exit;
FXoffLimit := Limit;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetByteSize( Size : TByteSize );
begin
if Size = FByteSize then
Exit;
FByteSize := Size;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetParity( p : TParity );
begin
if p = FParity then
Exit;
FParity := p;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetStopBits( Bits : TStopBits );
begin
if Bits = FStopBits then
Exit;
FStopBits := Bits;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetXonChar( c : AnsiChar );
begin
if c = FXonChar then
Exit;
FXonChar := c;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetXoffChar( c : AnsiChar );
begin
if c = FXoffChar then
Exit;
FXoffChar := c;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetReplacedChar( c : AnsiChar );
begin
if c = FReplacedChar then
Exit;
FReplacedChar := c;
if hCommFile <> 0 then
_SetCommState
end;
procedure TComm.SetReadIntervalTimeout( v : DWORD );
begin
if v = FReadIntervalTimeout then
Exit;
FReadIntervalTimeout := v;
if hCommFile <> 0 then
_SetCommTimeout
end;
procedure TComm.SetReadTotalTimeoutMultiplier( v : DWORD );
begin
if v = FReadTotalTimeoutMultiplier then
Exit;
FReadTotalTimeoutMultiplier := v;
if hCommFile <> 0 then
_SetCommTimeout
end;
procedure TComm.SetReadTotalTimeoutConstant( v : DWORD );
begin
if v = FReadTotalTimeoutConstant then
Exit;
FReadTotalTimeoutConstant := v;
if hCommFile <> 0 then
_SetCommTimeout
end;
procedure TComm.SetWriteTotalTimeoutMultiplier( v : DWORD );
begin
if v = FWriteTotalTimeoutMultiplier then
Exit;
FWriteTotalTimeoutMultiplier := v;
if hCommFile <> 0 then
_SetCommTimeout
end;
procedure TComm.SetWriteTotalTimeoutConstant( v : DWORD );
begin
if v = FWriteTotalTimeoutConstant then
Exit;
FWriteTotalTimeoutConstant := v;
if hCommFile <> 0 then
_SetCommTimeout
end;
(******************************************************************************)
//READ THREAD
(******************************************************************************)
//
//PROCEDURE: TReadThread.Execute
//
//PURPOSE: This is the starting point for the Read Thread.
//
//PARAMETERS:
// None.
//
//RETURN VALUE:
// None.
//
//COMMENTS:
//
// The Read Thread uses overlapped ReadFile and sends any data
// read from the comm port to the Comm32Window.This is
// eventually done through a PostMessage so that the Read Thread
// is never away from the comm port very long.This also provides
// natural desynchronization between the Read thread and the UI.
//
// If the CloseEvent object is signaled, the Read Thread exits.
//
// Separating the Read and Write threads is natural for a application
// where there is no need for synchronization between
// reading and writing.However, if there is such a need (for example,
// most file transfer algorithms synchronize the reading and writing),
// then it would make a lot more sense to have a single thread to handle
// both reading and writing.
//
//
procedure TReadThread.Execute;
var
szInputBuffer: array of Char;
nNumberOfBytesRead: DWORD;
HandlesToWaitFor: array of THandle;
dwHandleSignaled: DWORD;
fdwEvtMask: DWORD;
// Needed for overlapped I/O (ReadFile)
overlappedRead: TOverlapped;
// Needed for overlapped Comm Event handling.
overlappedCommEvent: TOverlapped;
label
EndReadThread;
begin
FillChar( overlappedRead, Sizeof(overlappedRead), 0 );
FillChar( overlappedCommEvent, Sizeof(overlappedCommEvent), 0 );
// Lets put an event in the Read overlapped structure.
overlappedRead.hEvent := CreateEvent( nil, True, True, nil);
if overlappedRead.hEvent = 0 then
begin
PostHangupCall;
goto EndReadThread
end;
// And an event for the CommEvent overlapped structure.
overlappedCommEvent.hEvent := CreateEvent( nil, True, True, nil);
if overlappedCommEvent.hEvent = 0 then
begin
PostHangupCall();
goto EndReadThread
end;
// We will be waiting on these objects.
HandlesToWaitFor := hCloseEvent;
HandlesToWaitFor := overlappedCommEvent.hEvent;
HandlesToWaitFor := overlappedRead.hEvent;
// Setup CommEvent handling.
// Set the comm mask so we receive error signals.
if not SetCommMask(hCommFile, EV_ERR or EV_RLSD or EV_RING ) then
begin
PostHangupCall;
goto EndReadThread
end;
// Start waiting for CommEvents (Errors)
if not SetupCommEvent( @overlappedCommEvent,fdwEvtMask ) then
goto EndReadThread;
// Start waiting for Read events.
if not SetupReadEvent( @overlappedRead,
szInputBuffer, INPUTBUFFERSIZE,
nNumberOfBytesRead ) then
goto EndReadThread;
// Keep looping until we break out.
while True do
begin
// Wait until some event occurs (data to read; error; stopping).
dwHandleSignaled := WaitForMultipleObjects(3, @HandlesToWaitFor,
False, INFINITE);
// Which event occured?
case dwHandleSignaled of
WAIT_OBJECT_0: // Signal to end the thread.
begin
// Time to exit.
goto EndReadThread
end;
WAIT_OBJECT_0 + 1: // CommEvent signaled.
begin
// Handle the CommEvent.
if not HandleCommEvent( @overlappedCommEvent, fdwEvtMask, TRUE ) then
goto EndReadThread;
// Start waiting for the next CommEvent.
if not SetupCommEvent( @overlappedCommEvent, fdwEvtMask ) then
goto EndReadThread
{break;??}
end;
WAIT_OBJECT_0 + 2: // Read Event signaled.
begin
// Get the new data!
if not HandleReadEvent( @overlappedRead,
szInputBuffer,
INPUTBUFFERSIZE,
nNumberOfBytesRead ) then
goto EndReadThread;
// Wait for more new data.
if not SetupReadEvent( @overlappedRead,
szInputBuffer, INPUTBUFFERSIZE,
nNumberOfBytesRead ) then
goto EndReadThread
{break;}
end;
WAIT_FAILED: // Wait failed.Shouldn't happen.
begin
PostHangupCall;
goto EndReadThread
end
else // This case should never occur.
begin
PostHangupCall;
goto EndReadThread
end
end {case dwHandleSignaled}
end; {while True}
// Time to clean up Read Thread.
EndReadThread:
PurgeComm( hCommFile, PURGE_RXABORT + PURGE_RXCLEAR );
CloseHandle( overlappedRead.hEvent );
CloseHandle( overlappedCommEvent.hEvent )
end; {TReadThread.Execute}
//
//FUNCTION: SetupReadEvent(LPOVERLAPPED, LPSTR, DWORD, LPDWORD)
//
//PURPOSE: Sets up an overlapped ReadFile
//
//PARAMETERS:
// lpOverlappedRead - address of overlapped structure to use.
// lpszInputBuffer - Buffer to place incoming bytes.
// dwSizeofBuffer - size of lpszInputBuffer.
// lpnNumberOfBytesRead- address of DWORD to place the number of read bytes.
//
//RETURN VALUE:
// TRUE if able to successfully setup the ReadFile.FALSE if there
// was a failure setting up or if the CloseEvent object was signaled.
//
//COMMENTS:
//
// This function is a helper function for the Read Thread.This
// function sets up the overlapped ReadFile so that it can later
// be waited on (or more appropriatly, so the event in the overlapped
// structure can be waited upon).If there is data waiting, it is
// handled and the next ReadFile is initiated.
// Another possible reason for returning FALSE is if the comm port
// is closed by the service provider.
//
//
//
function TReadThread.SetupReadEvent( lpOverlappedRead: POverlapped;
lpszInputBuffer: LPSTR; dwSizeofBuffer: DWORD;
var lpnNumberOfBytesRead: DWORD ): Boolean;
var
dwLastError: DWORD;
label
StartSetupReadEvent;
begin
Result := False;
StartSetupReadEvent:
// Make sure the CloseEvent hasn't been signaled yet.
// Check is needed because this function is potentially recursive.
if WAIT_TIMEOUT <> WaitForSingleObject(hCloseEvent,0) then
Exit;
// Start the overlapped ReadFile.
if ReadFile( hCommFile,
lpszInputBuffer^, dwSizeofBuffer,
lpnNumberOfBytesRead, lpOverlappedRead ) then
begin
// This would only happen if there was data waiting to be read.
// Handle the data.
if not HandleReadData( lpszInputBuffer, lpnNumberOfBytesRead ) then
Exit;
// Start waiting for more data.
goto StartSetupReadEvent
end;
// ReadFile failed.Expected because of overlapped I/O.
dwLastError := GetLastError;
// LastError was ERROR_IO_PENDING, as expected.
if dwLastError = ERROR_IO_PENDING then
begin
Result := True;
Exit
end;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
// Unexpected error come here. No idea what could cause this to happen.
PostHangupCall
end; {TReadThread.SetupReadEvent}
//
//FUNCTION: HandleReadData(LPCSTR, DWORD)
//
//PURPOSE: Deals with data after its been read from the comm file.
//
//PARAMETERS:
// lpszInputBuffer- Buffer to place incoming bytes.
// dwSizeofBuffer - size of lpszInputBuffer.
//
//RETURN VALUE:
// TRUE if able to successfully handle the data.
// FALSE if unable to allocate memory or handle the data.
//
//COMMENTS:
//
// This function is yet another helper function for the Read Thread.
// It LocalAlloc()s a buffer, copies the new data to this buffer and
// calls PostWriteToDisplayCtl to let the EditCtls module deal with
// the data.Its assumed that PostWriteToDisplayCtl posts the message
// rather than dealing with it right away so that the Read Thread
// is free to get right back to waiting for data.Its also assumed
// that the EditCtls module is responsible for LocalFree()ing the
// pointer that is passed on.
//
//
function TReadThread.HandleReadData( lpszInputBuffer: LPCSTR; dwSizeofBuffer: DWORD ): Boolean;
var
lpszPostedBytes: LPSTR;
begin
Result := False;
// If we got data and didn't just time out empty...
if dwSizeofBuffer <> 0 then
begin
// Do something with the bytes read.
lpszPostedBytes := PChar( LocalAlloc( LPTR, dwSizeofBuffer+1 ) );
if lpszPostedBytes = nil{NULL} then
begin
// Out of memory
PostHangupCall;
Exit
end;
Move( lpszInputBuffer^, lpszPostedBytes^, dwSizeofBuffer );
lpszPostedBytes := #0;
Result := ReceiveData( lpszPostedBytes, dwSizeofBuffer )
end
end; {TReadThread.HandleReadData}
//
//FUNCTION: HandleReadEvent(LPOVERLAPPED, LPSTR, DWORD, LPDWORD)
//
//PURPOSE: Retrieves and handles data when there is data ready.
//
//PARAMETERS:
// lpOverlappedRead - address of overlapped structure to use.
// lpszInputBuffer - Buffer to place incoming bytes.
// dwSizeofBuffer - size of lpszInputBuffer.
// lpnNumberOfBytesRead- address of DWORD to place the number of read bytes.
//
//RETURN VALUE:
// TRUE if able to successfully retrieve and handle the available data.
// FALSE if unable to retrieve or handle the data.
//
//COMMENTS:
//
// This function is another helper function for the Read Thread.This
// is the function that is called when there is data available after
// an overlapped ReadFile has been setup.It retrieves the data and
// handles it.
//
//
function TReadThread.HandleReadEvent( lpOverlappedRead: POverlapped;
lpszInputBuffer: LPSTR; dwSizeofBuffer: DWORD;
var lpnNumberOfBytesRead: DWORD ): Boolean;
var
dwLastError: DWORD;
begin
Result := False;
if GetOverlappedResult( hCommFile,
lpOverlappedRead^, lpnNumberOfBytesRead, False ) then
begin
Result := HandleReadData( lpszInputBuffer, lpnNumberOfBytesRead );
Exit
end;
// Error in GetOverlappedResult; handle it.
dwLastError := GetLastError;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
// Unexpected error come here. No idea what could cause this to happen.
PostHangupCall
end; {TReadThread.HandleReadEvent}
//
//FUNCTION: SetupCommEvent(LPOVERLAPPED, LPDWORD)
//
//PURPOSE: Sets up the overlapped WaitCommEvent call.
//
//PARAMETERS:
// lpOverlappedCommEvent - Pointer to the overlapped structure to use.
// lpfdwEvtMask - Pointer to DWORD to received Event data.
//
//RETURN VALUE:
// TRUE if able to successfully setup the WaitCommEvent.
// FALSE if unable to setup WaitCommEvent, unable to handle
// an existing outstanding event or if the CloseEvent has been signaled.
//
//COMMENTS:
//
// This function is a helper function for the Read Thread that sets up
// the WaitCommEvent so we can deal with comm events (like Comm errors)
// if they occur.
//
//
function TReadThread.SetupCommEvent( lpOverlappedCommEvent: POverlapped;
var lpfdwEvtMask: DWORD ): Boolean;
var
dwLastError: DWORD;
label
StartSetupCommEvent;
begin
Result := False;
StartSetupCommEvent:
// Make sure the CloseEvent hasn't been signaled yet.
// Check is needed because this function is potentially recursive.
if WAIT_TIMEOUT <> WaitForSingleObject( hCloseEvent,0 ) then
Exit;
// Start waiting for Comm Errors.
if WaitCommEvent( hCommFile, lpfdwEvtMask, lpOverlappedCommEvent ) then
begin
// This could happen if there was an error waiting on the
// comm port.Lets try and handle it.
if not HandleCommEvent( nil, lpfdwEvtMask, False ) then
begin
{??? GetOverlappedResult does not handle "NIL" as defined by Borland}
Exit
end;
// What could cause infinite recursion at this point?
goto StartSetupCommEvent
end;
// We expect ERROR_IO_PENDING returned from WaitCommEvent
// because we are waiting with an overlapped structure.
dwLastError := GetLastError;
// LastError was ERROR_IO_PENDING, as expected.
if dwLastError = ERROR_IO_PENDING then
begin
Result := True;
Exit
end;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
// Unexpected error. No idea what could cause this to happen.
PostHangupCall
end; {TReadThread.SetupCommEvent}
//
//FUNCTION: HandleCommEvent(LPOVERLAPPED, LPDWORD, BOOL)
//
//PURPOSE: Handle an outstanding Comm Event.
//
//PARAMETERS:
// lpOverlappedCommEvent - Pointer to the overlapped structure to use.
// lpfdwEvtMask - Pointer to DWORD to received Event data.
// fRetrieveEvent - Flag to signal if the event needs to be
// retrieved, or has already been retrieved.
//
//RETURN VALUE:
// TRUE if able to handle a Comm Event.
// FALSE if unable to setup WaitCommEvent, unable to handle
// an existing outstanding event or if the CloseEvent has been signaled.
//
//COMMENTS:
//
// This function is a helper function for the Read Thread that (if
// fRetrieveEvent == TRUE) retrieves an outstanding CommEvent and
// deals with it.The only event that should occur is an EV_ERR event,
// signalling that there has been an error on the comm port.
//
// Normally, comm errors would not be put into the normal data stream
// as this sample is demonstrating.Putting it in a status bar would
// be more appropriate for a real application.
//
//
function TReadThread.HandleCommEvent( lpOverlappedCommEvent: POverlapped;
var lpfdwEvtMask: DWORD; fRetrieveEvent: Boolean ): Boolean;
var
dwDummy: DWORD;
dwErrors: DWORD;
dwLastError: DWORD;
dwModemEvent: DWORD;
begin
Result := False;
// If this fails, it could be because the file was closed (and I/O is
// finished) or because the overlapped I/O is still in progress.In
// either case (or any others) its a bug and return FALSE.
if fRetrieveEvent then
begin
if not GetOverlappedResult( hCommFile,
lpOverlappedCommEvent^, dwDummy, False ) then
begin
dwLastError := GetLastError;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
PostHangupCall;
Exit
end
end;
// Was the event an error?
if (lpfdwEvtMask and EV_ERR) <> 0 then
begin
// Which error was it?
if not ClearCommError( hCommFile, dwErrors, nil ) then
begin
dwLastError := GetLastError;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
PostHangupCall;
Exit
end;
// Its possible that multiple errors occured and were handled
// in the last ClearCommError.Because all errors were signaled
// individually, but cleared all at once, pending comm events
// can yield EV_ERR while dwErrors equals 0.Ignore this event.
if not ReceiveError( dwErrors ) then
Exit;
Result := True
end;
dwModemEvent := 0;
if ((lpfdwEvtMask and EV_RLSD) <> 0) then
dwModemEvent := ME_RLSD;
if ((lpfdwEvtMask and EV_RING) <> 0) then
dwModemEvent := dwModemEvent or ME_RING;
if dwModemEvent <> 0 then
begin
if not ModemStateChange( dwModemEvent ) then
begin
Result := False;
Exit
end;
Result := True
end;
if ((lpfdwEvtMask and EV_ERR)=0) and (dwModemEvent=0) then
begin
// Should not have gotten here.
PostHangupCall
end
end; {TReadThread.HandleCommEvent}
function TReadThread.ReceiveData( lpNewString: LPSTR; dwSizeofNewString: DWORD ): BOOL;
begin
Result := False;
if not PostMessage( hComm32Window, PWM_GOTCOMMDATA,
WPARAM(dwSizeofNewString), LPARAM(lpNewString) ) then
PostHangupCall
else
Result := True
end;
function TReadThread.ReceiveError( EvtMask : DWORD ): BOOL;
begin
Result := False;
if not PostMessage( hComm32Window, PWM_RECEIVEERROR, 0, LPARAM(EvtMask) ) then
PostHangupCall
else
Result := True
end;
function TReadThread.ModemStateChange( ModemEvent : DWORD ) : BOOL;
begin
Result := False;
if not PostMessage( hComm32Window, PWM_MODEMSTATECHANGE, 0, LPARAM(ModemEvent) ) then
PostHangupCall
else
Result := True
end;
procedure TReadThread.PostHangupCall;
begin
PostMessage( hComm32Window, PWM_REQUESTHANGUP, 0, 0 )
end;
(******************************************************************************)
//WRITE THREAD
(******************************************************************************)
//
//PROCEDURE: TWriteThread.Execute
//
//PURPOSE: The starting point for the Write thread.
//
//PARAMETERS:
// lpvParam - unused.
//
//RETURN VALUE:
// DWORD - unused.
//
//COMMENTS:
//
// The Write thread uses a PeekMessage loop to wait for a string to write,
// and when it gets one, it writes it to the Comm port.If the CloseEvent
// object is signaled, then it exits.The use of messages to tell the
// Write thread what to write provides a natural desynchronization between
// the UI and the Write thread.
//
//
procedure TWriteThread.Execute;
var
msg: TMsg;
dwHandleSignaled: DWORD;
overlappedWrite: TOverLapped;
CompleteOneWriteRequire : Boolean;
label
EndWriteThread;
begin
// Needed for overlapped I/O.
FillChar( overlappedWrite, SizeOf(overlappedWrite), 0 );{0, 0, 0, 0, NULL}
overlappedWrite.hEvent := CreateEvent( nil, True, True, nil );
if overlappedWrite.hEvent = 0 then
begin
PostHangupCall;
goto EndWriteThread
end;
CompleteOneWriteRequire := True;
// This is the main loop.Loop until we break out.
while True do
begin
if not PeekMessage( msg, 0, 0, 0, PM_REMOVE ) then
begin
// If there are no messages pending, wait for a message or
// the CloseEvent.
pFSendDataEmpty^ := True;
if CompleteOneWriteRequire then
begin
if not PostMessage( hComm32Window, PWM_SENDDATAEMPTY, 0, 0 ) then
begin
PostHangupCall;
goto EndWriteThread
end
end;
CompleteOneWriteRequire := False;
dwHandleSignaled := MsgWaitForMultipleObjects(1, hCloseEvent, False,
INFINITE, QS_ALLINPUT);
case dwHandleSignaled of
WAIT_OBJECT_0: // CloseEvent signaled!
begin
// Time to exit.
goto EndWriteThread
end;
WAIT_OBJECT_0 + 1: // New message was received.
begin
// Get the message that woke us up by looping again.
Continue
end;
WAIT_FAILED: // Wait failed.Shouldn't happen.
begin
PostHangupCall;
goto EndWriteThread
end
else // This case should never occur.
begin
PostHangupCall;
goto EndWriteThread
end
end
end;
// Make sure the CloseEvent isn't signaled while retrieving messages.
if WAIT_TIMEOUT <> WaitForSingleObject(hCloseEvent,0) then
goto EndWriteThread;
// Process the message.
// This could happen if a dialog is created on this thread.
// This doesn't occur in this sample, but might if modified.
if msg.hwnd <> 0{NULL} then
begin
TranslateMessage(msg);
DispatchMessage(msg);
Continue
end;
// Handle the message.
case msg.message of
PWM_COMMWRITE:// New string to write to Comm port.
begin
// Write the string to the comm port.HandleWriteData
// does not return until the whole string has been written,
// an error occurs or until the CloseEvent is signaled.
if not HandleWriteData( @overlappedWrite,
PChar(msg.lParam), DWORD(msg.wParam) ) then
begin
// If it failed, either we got a signal to end or there
// really was a failure.
LocalFree( HLOCAL(msg.lParam) );
goto EndWriteThread
end;
CompleteOneWriteRequire := True;
// Data was sent in a LocalAlloc()d buffer.Must free it.
LocalFree( HLOCAL(msg.lParam) )
end
end
end; {main loop}
// Thats the end.Now clean up.
EndWriteThread:
PurgeComm(hCommFile, PURGE_TXABORT + PURGE_TXCLEAR);
pFSendDataEmpty^ := True;
CloseHandle(overlappedWrite.hEvent)
end; {TWriteThread.Execute}
//
//FUNCTION: HandleWriteData(LPOVERLAPPED, LPCSTR, DWORD)
//
//PURPOSE: Writes a given string to the comm file handle.
//
//PARAMETERS:
// lpOverlappedWrite- Overlapped structure to use in WriteFile
// pDataToWrite - String to write.
// dwNumberOfBytesToWrite - Length of String to write.
//
//RETURN VALUE:
// TRUE if all bytes were written.False if there was a failure to
// write the whole string.
//
//COMMENTS:
//
// This function is a helper function for the Write Thread.It
// is this call that actually writes a string to the comm file.
// Note that this call blocks and waits for the Write to complete
// or for the CloseEvent object to signal that the thread should end.
// Another possible reason for returning FALSE is if the comm port
// is closed by the service provider.
//
//
function TWriteThread.HandleWriteData( lpOverlappedWrite: POverlapped;
pDataToWrite: PChar; dwNumberOfBytesToWrite: DWORD): Boolean;
var
dwLastError,
dwNumberOfBytesWritten,
dwWhereToStartWriting,
dwHandleSignaled: DWORD;
HandlesToWaitFor: array of THandle;
begin
Result := False;
dwNumberOfBytesWritten := 0;
dwWhereToStartWriting := 0; // Start at the beginning.
HandlesToWaitFor := hCloseEvent;
HandlesToWaitFor := lpOverlappedWrite^.hEvent;
// Keep looping until all characters have been written.
repeat
// Start the overlapped I/O.
if not WriteFile( hCommFile,
pDataToWrite[ dwWhereToStartWriting ],
dwNumberOfBytesToWrite, dwNumberOfBytesWritten,
lpOverlappedWrite ) then
begin
// WriteFile failed.Expected; lets handle it.
dwLastError := GetLastError;
// Its possible for this error to occur if the
// service provider has closed the port.Time to end.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
// Unexpected error.No idea what.
if dwLastError <> ERROR_IO_PENDING then
begin
PostHangupCall;
Exit
end;
// This is the expected ERROR_IO_PENDING case.
// Wait for either overlapped I/O completion,
// or for the CloseEvent to get signaled.
dwHandleSignaled := WaitForMultipleObjects(2, @HandlesToWaitFor,
False, INFINITE);
case dwHandleSignaled of
WAIT_OBJECT_0: // CloseEvent signaled!
begin
// Time to exit.
Exit
end;
WAIT_OBJECT_0 + 1: // Wait finished.
begin
// Time to get the results of the WriteFile
if not GetOverlappedResult(hCommFile,
lpOverlappedWrite^,
dwNumberOfBytesWritten, True) then
begin
dwLastError := GetLastError;
// Its possible for this error to occur if the
// service provider has closed the port.
if dwLastError = ERROR_INVALID_HANDLE then
Exit;
// No idea what could cause another error.
PostHangupCall;
Exit
end
end;
WAIT_FAILED: // Wait failed.Shouldn't happen.
begin
PostHangupCall;
Exit
end
else // This case should never occur.
begin
PostHangupCall;
Exit
end
end {case}
end; {WriteFile failure}
// Some data was written.Make sure it all got written.
Dec( dwNumberOfBytesToWrite, dwNumberOfBytesWritten );
Inc( dwWhereToStartWriting, dwNumberOfBytesWritten )
until (dwNumberOfBytesToWrite <= 0);// Write the whole thing!
// Wrote the whole string.
Result := True
end; {TWriteThread.HandleWriteData}
procedure TWriteThread.PostHangupCall;
begin
PostMessage( hComm32Window, PWM_REQUESTHANGUP, 0, 0 )
end;
procedure Register;
begin
RegisterComponents('System', )
end;
end.
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