C++和pascal之間的通訊

// MyFirst.cpp : 定義控制檯應用程式的入口點。
//

#include "stdafx.h"
#include "Winsock2.h"
#pragma comment(lib,"ws2_32.lib")

int _tmain(int argc, _TCHAR* argv[])
{
    WORD wVersionRequested;
 WSADATA wsaData;
 int err;

 wVersionRequested = MAKEWORD(1,1);

 err = WSAStartup(wVersionRequested,&wsaData);
 if (err!=0)
 {
  return 0;
 }

 if (LOBYTE(wsaData.wVersion)!=1||
  HIBYTE(wsaData.wVersion)!=1)
 {
  WSACleanup();
  return 0;
 }
 SOCKET sockSrv=socket(AF_INET,SOCK_STREAM,0);

 SOCKADDR_IN addrSrv;
 addrSrv.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
 addrSrv.sin_family=AF_INET;
 addrSrv.sin_port=htons(5101);

 bind(sockSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));

 listen(sockSrv,5);

 SOCKADDR_IN addrClient;
 int len=sizeof(SOCKADDR);
 while(1)
 {
  SOCKET sockConn=accept(sockSrv,(SOCKADDR*)&addrClient,&len);
  char sendBuf[100];
    // sprintf_s(sendBuf,"Welcome %s to here!",inet_ntoa(addrClient.sin_addr));
  /*send(sockConn,sendBuf,strlen(sendBuf)+1,0);*send函式是將指定長度的資料複製到TCP的系統緩衝區，然後系統緩衝區負責傳送流資料到接收端的緩衝區
               recv負責從緩衝區複製資料到指定儲存地址位元組不一樣又沒事的，recv每次不一定接收固定的資料的*/
  char recvBuf[100];
  memset(recvBuf,0,sizeof(recvBuf));
  recv(sockConn,recvBuf,sizeof(recvBuf),0);
  printf("%s\n",recvBuf);
  memset(recvBuf,0,sizeof(recvBuf));
  recv(sockConn,recvBuf,sizeof(recvBuf),0);
  printf("%s\n",recvBuf);
  closesocket(sockConn);}
   
 return 0;
}

網上找的一段程式碼用C++重寫了一遍然後用pascal寫的客戶端傳送；

發現總是無法接受到正常的資料，在經過N邊檢查之後，才明白。

問題出現在客戶端傳送哪裡有一個資料大小驗證。

unit uSendMsg;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,IdTCPClient,WinSock, IdBaseComponent, IdComponent,
  IdTCPConnection;

type
  TFSendMsg = class(TForm)
    btnsend: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Button1: TButton;
    Memo1: TMemo;
    Label3: TLabel;
    Edit3: TEdit;
    Label4: TLabel;
    Button2: TButton;
    dlg: TOpenDialog;
    procedure btnsendClick(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Memo1Click(Sender: TObject);
    procedure Edit3Click(Sender: TObject);
  private
    { Private declarations }
    client: TIdTCPClient;
    procedure sendSplitText(client: TIdTCPClient; s: String);
    Procedure SendFile(IFileName:string);
  public
    { Public declarations }
  end;

var
  FSendMsg: TFSendMsg;

implementation
uses IdGlobal,IniFiles;
{$R *.dfm}

procedure TFSendMsg.btnsendClick(Sender: TObject);
var
  iLength: Integer;
  s,s1,sSendText: String;
  flag: Boolean;
  aText: string;
begin
  try
    if client.Connected() then
      client.Disconnect();
    if not client.Connected() then
    begin
      client.Host := trim(edit1.Text);
      client.Port := strtoint(trim(edit2.Text));
      client.Connect();
     // showmessage('連線成功');
    end;
  except on E: Exception do
  begin
      showMessage('連線主機失敗,錯誤描述:'+ E.Message);
      exit;
  end;
  end;
  if not memo1.ReadOnly then
  begin
    try
       aText := trim(memo1.Text);
       if atext = '' then begin
          showmessage('No message send');
          exit;
       end;
       iLength := Length(aText);
       sSendText := intToStr(100000000 + iLength);
       Delete(sSendText, 1, 1);
       sSendText := sSendText + aText;
       if client.Connected() then
         sendSplitText(client,sSendText);
       showmessage('傳送成功');
    except on E: Exception do
      ShowMessage('傳送失敗,錯誤描述:'+ E.Message);
    end;
  end else
  begin
  //  edit3.Text :=  'E:\華騰專案軟體\sendmsg\a.txt';
    s1 := trim(edit3.Text);
    if s1 = '' then begin
      showmessage('請選擇檔案');
      exit;
    end;
    try
      if client.Connected() then
         sendfile(s1);
      showmessage('傳送成功');
    except on E: Exception do
      ShowMessage('傳送失敗,錯誤描述:'+ E.Message);
    end;
  end;
end;

procedure TFSendMsg.Button1Click(Sender: TObject);
begin
  close;
end;

procedure TFSendMsg.Button2Click(Sender: TObject);
begin
  btnsend.Enabled := true;
  edit3.ReadOnly := false;
  memo1.ReadOnly := true;
  if dlg.Execute then
   edit3.Text := dlg.FileName;
end;

procedure TFSendMsg.Edit3Click(Sender: TObject);
begin
  btnsend.Enabled := true;
  edit3.ReadOnly := false;
  memo1.ReadOnly := true;
end;

procedure TFSendMsg.FormShow(Sender: TObject);
var
  s: string;
  ini: TIniFile;
begin
  client := TIdTCPClient.Create(nil);
  s := ExtractFilePath(Application.ExeName)+'info.ini';
  if not fileExists(s) then
  begin
    ShowMessage('未找到配置檔案'+ s);
    Application.Terminate;
    exit;
  end;
  ini := TIniFile.Create(s);
  Edit1.Text := ini.ReadString('info','ip','');
  Edit2.Text := IntToStr(ini.ReadInteger('info','port',0));
  Edit3.Text := ini.ReadString('info','path','');
  ini.Free;
end;

procedure TFSendMsg.Memo1Click(Sender: TObject);
begin
  btnsend.Enabled := true;
  edit3.ReadOnly := true;
  memo1.ReadOnly := false;
end;

procedure TFSendMsg.SendFile(IFileName: string);
var
  iFileHandle:integer;
  iFileLen,cnt:integer;
  buf:array[0..4096] of byte;
  mdata: TBytes;
  cc: array[0..3000] of char;
  bb: array[0..3000] of char;
  aa: array[0..3000] of char;
  sText,sSendText: string;
  i,iLength,isum: integer;
begin
  iFileHandle:=FileOpen(IFileName,fmOpenRead);
  iFileLen:=FileSeek(iFileHandle,0,2);   //返回檔案共多少個字元
  FileSeek(iFileHandle,0,0);  //指標指向檔案開頭

  FillChar(cc, sizeof(cc),0);
  cnt := FileRead(iFileHandle,cc,iFileLen);

  sSendText := intToStr(100000000 + iFileLen);
  Delete(sSendText, 1, 1);
  FillChar(aa, sizeof(aa),0);
  for i := 1 to 8 do
      aa[i-1] := sSendText[i];
  mdata := rawtobytes(aa, 8);
  client.Socket.Write(mdata);

  isum := 0;
  while iFileLen > 1000 do
  begin
    FillChar(bb, sizeof(bb),0);
    for i := 0 to 1000 - 1 do
      bb[i] := cc[i+isum];
    mdata := rawtobytes(bb, 1000);
    client.Socket.Write(mdata);
    isum := isum + 1000;
    iFileLen := iFileLen - 1000;
  end;

  if iFileLen > 0 then
  begin
    FillChar(bb, sizeof(bb),0);
    for i := 0 to iFileLen - 1 do
      bb[i] := cc[i+isum];
    mdata := rawtobytes(bb, iFileLen);
    client.Socket.Write(mdata);
  end;

  FileClose(iFileHandle);
end;

procedure TFSendMsg.sendSplitText(client: TIdTCPClient; s: String);
var
  strStream:TStringStream;
  sText, s1: String;
  mdata: TBytes;
  cc: array[0..3000] of char;
  i: Integer;
begin
  sText := s;
  FillChar(cc, sizeof(cc),0);
  for i := 1 to 18 do
      cc[i-1] := sText[i];
  mdata := rawtobytes(cc, 18);
  client.Socket.Write(mdata);
  Delete(sText,1,18);
  while Length(sText) > 1000 do
  begin
    s1 := Copy(sText,1,1000);
    FillChar(cc, sizeof(cc),0);
    for i := 1 to Length(s1) do
      cc[i-1] := s1[i];
    mdata := rawtobytes(cc, 1000);
    client.Socket.Write(mdata);
    Delete(sText,1,1000);
  end;
  if Length(sText) > 0 then
  begin
    FillChar(cc, sizeof(cc),0);
    for i := 1 to Length(sText) do
      cc[i-1] := sText[i];
    mdata := rawtobytes(cc, Length(sText));
    client.Socket.Write(mdata);
  end;
end;