LongDataTransfer.pas

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>> Ïðîöåäóðû ïåðåäà÷è è ïðèåìà äëèííûõ áëîêîâ äàííûõ, ñ ó÷åòîì ôðàãìåíòàöèè
è âîçìîæíîé ñëåïêè ïàêåòîâ. Íà êîìïîíåíòû TServerSocket,TClientSocket ..SendText

Äàííàÿ ìîäóëü ñîäåðæèò ôóíêöèè, êîòîðûå ïîçâîëÿåò ïðèíèìàòü è îòïðàâëÿòü äëèííûå áëîêè äàííûõ.
 êîä âñòðåíà àâòîìàòè÷åñêàÿ îáðàáîòêà ôðàãìåíòàöèè è ñëåïêè ïàêåòîâ.
Äàííûå ïðîöåëóðû ïðåäíàçíà÷åíû äëÿ ïåðåäà÷è òåêñòîâûõ ñòðîê, è èñïîëüçóþò
ìåòîäû SendText, ReciveText TCustomSocket è ïðåäíàçíà÷åíû äëÿ èñïîëüçîâàíèÿ
ñ êîìïîíåíòàìè TClientSocket, TServerSocket è äðóãèõ ïðîèçâîäíûõ îò TCustomSocket.
Äàííûå ðåøåíèå îòëè÷àåòñÿ ïðîñòîòîé èñïîëüçîâàíèÿ, ñêîðîñòüþ îáðàáîòêè è íàäåæíîñòüþ:
òåñòèðîâàëîñü ïîñûëêîé áëîêîâ äàííûõ ðàçìåðîì 1-16000, áûëî îáðàáîòàíî 15100 áëîêîâ äàííûõ.
Ïîñëåäóþùåå ñðàâíåíèå îòïðàâëåííõ è ïîëó÷åííûõ äàííûõ ïîêàçàëî îòñóòâèå êàêèõ ëèáî
îøèáîê ïðè ïåðåäà÷è, ñáîðêè è ôðàãìåíòàöèè äàííûõ.

Ïåðåä èñïîëüçîâàíèåì íóæíî ïðèãîòîâèòü ïîëüçîâàòåëüñêóþ ïðîöåäóðó, êîòîðàÿ
áóäåò âûçûâàòüñÿ êàæäûé ðàç, êîãäà ïîëó÷åí î÷åðåäíîé ÁËÎÊ äàííûõ. Äàííàÿ ïðîöåäóðà
äîëæíà èìåòü ÎÄÈÍ âõîäíîé ïàðàìåòð òèïà STRING:

procedure SomeUserProc(S:String);
begin
....
end;

Ìîäóëü ñîäåðæèò 3 ôóíêöèè, èç êîòîðûõ ïîëüçüçîâàòåëþ íóæíû òîëüêî 2
function SendLongText(Socket:TCustomWinSocket; S:String):boolean;
function ReceiveLongText(Socket:TCustomWinSocket;MySProc:TMySProc;SafeCalledStr :string = ''):boolean;
Ôóíöèÿ SendText ñëóæèò äëÿ îòïðàâêè ïàêåòîâ.  êà÷åñòâå ïàðàìåòðîâ åé ïåðäàåòñÿ
îáúåêò TCustomWinSocket (íàïðèìåð ýòî ClientSocket.Socket) è ñîáñòâåííî
îòïðàâëÿåìÿ ñòðîêà S (ShortString,AnsiString,WideString).
 ñëó÷àå óñïåøíîé îòïðàâêè ôóíêöèÿ âîçâðàùàåò true, èíà÷å false.
Äëÿ îáðàáîòêè èñïîëüçóéòå GetLastError().

function ReceiveLongText(Socket:TCustomWinSocket;MySProc:TMySProc;SafeCalledStr :string = ''):boolean;
Èñïîëüçóåòñÿ äëÿ ïîëó÷åíèÿ. Äàííàõ ôóíöèÿ äîëæíà áûòü âûçâàíà â ñîáûòèè On*Read êîìïîíåíòà.
 êà÷åñòâå ïàðàìåòðîâ íåîáõîäèìî ïåðåäàòü TCustomWinSocket (íàïðèìåð ServerSocket.Socket) è èìÿ ïðîöåäóðû,
íàçíà÷åííîé äëÿ îáðàáîòêè äàííûõ (íàïðèìåð, ðàíåå ïðèãîòîâëåííàÿ SomeUserProc).
Òðåòèé ïàðàìåòð ÇÀÏÎËÍßÒÜ ÍÅ ÑËÅÄÓÅÒ!!!
Ïðîöåäóðà FlushBuffers ÿâëÿåòñÿ âíóòðåííåé è î÷èùàåò áóôåð ïðèåìà,
è íàïðÿìóþ ïîëüçîâàòåëåì âûçûâàòüñÿ íå äîëæíà.

Çàâèñèìîñòè: ScktComp;
Àâòîð:       Subfire, subfire@mail.ru, ICQ:55161852, Ñàíêò-Ïåòåðáóðã
Copyright:   Åãîðîâ Âèêòîð aka Subfire
Äàòà:        2 îêòÿáðÿ 2002 ã.
***************************************************** }

unit LongDataTransfer;

interface
uses Windows, SysUtils, Classes, ScktComp, comm_info, comm_data;
type
  TMySProc = procedure(const S: String);
function SendLongText(Socket: TCustomWinSocket; S: string): boolean;
function ReceiveLongText(Socket: TCustomWinSocket; MySProc: TMySProc;
  SafeCalledStr: AnsiString = ''): boolean;
procedure FlushBuffers;

var
  InputBuf: AnsiString;
  InputDataSize: LongWord;
  InputReceivedSize: LongWord;

implementation

function SendLongText(Socket: TCustomWinSocket; S: string): boolean;
var
  TextSize: DWord;
  SendStream: TMemoryStream;
begin
  Result := True;
  try
    if not Socket.Connected then
      Exit;
    TextSize := Length(S);
    SendStream := TMemoryStream.Create;
    SendStream.WriteBuffer(TextSize, 4);
    SendStream.WriteBuffer(PChar(S)^, TextSize * 2);
    SendStream.Seek(0, soFromBeginning);
    Socket.SendStream(SendStream);
  except Result := False;
  end;
end;

procedure FlushBuffers;
begin
  InputBuf := '';
  InputDataSize := 0;
  InputReceivedSize := 0;
end;

procedure CallSFunc(MySProc: TMySProc; Str: AnsiString); inline;
var
	CallStr: String;
begin
	SetLength(CallStr, Length(Str) div 2);
  CopyMemory(@CallStr[1], @Str[1], Length(Str));
  MySProc(CallStr);
end;

function ReceiveLongText(Socket:TCustomWinSocket;MySProc:TMySProc;SafeCalledStr :AnsiString = ''):boolean;
var
	S:AnsiString;
	RDSize:LongWord;
begin
Result:=True;
try
If SafeCalledStr='' then begin
	RDSize:=Socket.ReceiveLength;
	SetLength(S, RDSize);
	Socket.ReceiveBuf(S[1], RDSize);
end
else begin
	S:=SafeCalledStr;
	RDSize:=length(S);
end;
//PCorePlugin^.WriteLog(file_debug, 'Packet: '+IntToStr(RDSize)+' '+IntToStr(InputReceivedSize)+' '+IntToStr(InputDataSize));
if InputDataSize > 500000 then
	PCorePlugin^.WriteLog(file_debug, 'Warning: Packet: '+IntToStr(RDSize)+' '+IntToStr(InputReceivedSize)+' '+IntToStr(InputDataSize));
If (Length(InputBuf)>0) and (InputDataSize = 0) then begin //Êîððåêòèðîâêà, â òîì ñëó÷àå
	S:=InputBuf+S; //åñëè ôðàãìåíòèðîâàí ñàì çàãîëîâîê
	FlushBuffers; //áëîêà äàííûõ
  RDSize:=length(S);
end;
If InputDataSize=0 then
	begin //Ñàìûé ïåðâûé ïàêåò;
  	// Ôðàãìåíò çàãîëîâêà
  	if Length(S) < 4 then
    begin
      InputBuf := S;
      Exit;
    end;
  	CopyMemory(@InputDataSize, @S[1], 4);
		InputDataSize := InputDataSize * 2;
 		//MessageBox(0, PChar('First: '+IntToStr(RDSize)+' '+IntToStr(InputReceivedSize)+' '+IntToStr(InputDataSize)), '', 0);
 		if InputDataSize=RDSize-4 then begin //Îäèí áëîê â ïàêåòå
 			InputBuf:=Copy(S,5,RDSize-4); //íè ñëåïêè, íè ôðàãìåíòàöèè íåò.
 			CallSFunc(MySProc, InputBuf);
 			FlushBuffers;
 			Exit;
		end;
 		if InputDataSize<RDSize-4 then begin //Ïàêåò ñëåïëåí.
			InputBuf:=Copy(S,5,InputDataSize);
			CallSFunc(MySProc, InputBuf);
			Delete(S,1,InputDataSize+4);
			FlushBuffers;
			ReceiveLongText(Socket,MySProc,S);
			Exit;
 		end;
 		if InputDataSize>RDSize-4 then begin //ýòî ÏÅÐÂÛÉ ôðàãìåíò
    	InputBuf:=Copy(S,5,RDSize-4); //áîëüøîãî ïàêåòà
    	InputReceivedSize:=RDSize-4;
 		end;
	end
	else begin //Áóôåð ïðèåìà íå ïóñò
		//InputBuf:=
		If RDSize+InputReceivedSize=InputDataSize then
    begin //Ïîëó÷èëè ïîñëåäíèé
    	InputBuf:=InputBuf+Copy(S,1,RDSize); //ôðàãìåíò öåëèêîì
      CallSFunc(MySProc, InputBuf); //â ïàêåòå, äàííûõ
      FlushBuffers; // â ïàêåòå áîëüøå íåò
      Exit;
    end;
		If RDSize+InputReceivedSize<InputDataSize then // Ïîëó÷èëè
    begin //î÷åðåäíîé
    	InputBuf:=InputBuf+Copy(S,1,RDSize); //ôðàãìåíò
    	InputReceivedSize:=InputReceivedSize+RDSize;
    	Exit;
    end;
		If RDSize+InputReceivedSize>InputDataSize then //Ïîëåäíèé ôðàãìåíò
    begin // íî â ïàêåòå åñòü åùå äàííûå - ñëåïëåí.
    	InputBuf:=InputBuf+Copy(S,1,InputDataSize-InputReceivedSize);
      CallSFunc(MySProc, InputBuf);
      Delete(S,1,InputDataSize-InputReceivedSize);
      FlushBuffers;
      ReceiveLongText(Socket,MySProc,S);
    end;
	end;
except Result := false;//MessageBox(0, PChar(IntToStr(RDSize)+' '+IntToStr(InputReceivedSize)+' '+IntToStr(InputDataSize)), '', 0);//Result:=False;
end;
end;

end.