unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    Button2: TButton;
    Button3: TButton;
    Memo1: TMemo;
    Edit1: TEdit;
    Label1: TLabel;
    Button4: TButton;
    Label2: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.Button1Click(Sender: TObject);
var
  Stream1, Stream2: TFileStream;
begin
  if OpenDialog1.Execute and SaveDialog1.Execute then
  begin
    Stream1 := TFileStream.Create (
      OpenDialog1.FileName, fmOpenRead);
    try
      Stream2 := TFileStream.Create (
        SaveDialog1.FileName, fmOpenWrite or fmCreate);
      try
        Stream1.Position:=Stream1.Size-1024;
        Stream2.CopyFrom (Stream1, 1024);
      finally
        Stream2.Free;
      end;
    finally
      Stream1.Free;
    end;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
 var s:TStream;
begin
 s:=TFileStream.Create('C:\sample.txt',fmCreate or fmOpenWrite);
 s.Size:=1024*1024*1024; //1Gb;
 s.Free;
end;

//Main procedure.
procedure TForm1.Button3Click(Sender: TObject);
var
  Stream1, Stream2: TFileStream;  //Stream1 - Src stream; Stream2 - Dest stream;
  buf:PChar; //Buffer for readed data
  pos,rlen:Integer; //pos - position for read in Stream1. rlen - length in bytes to read Stream1
  bufsize:Integer; //size of buffer
label m; //label for loop
begin
try
  if OpenDialog1.Execute and SaveDialog1.Execute then
  begin
  pos:=0;
  bufsize:=StrToInt(Edit1.Text)*1024*1024; // bufsize in KB.
m:
    Stream1 := TFileStream.Create (OpenDialog1.FileName, fmOpenRead);   //create input stream for read data
    try
      //create output stream for write readed data.  WinAPI: CreateFile
      If not FileExists(SaveDialog1.FileName) then
       Stream2 := TFileStream.Create (SaveDialog1.FileName, fmOpenWrite or fmCreate)
      else
       Stream2 := TFileStream.Create (SaveDialog1.FileName, fmOpenWrite);


      try
        GetMem(Buf, bufsize); //-get memory for readed data
        if Stream1.Size-Stream2.Size>bufsize then rlen:=bufsize else rlen:=Stream1.Size-Stream2.Size;

        //read data to buffer and write it to file. WinAPI: ReadFile, WriteFile, SetFilePointer
        Stream1.Position:=pos;
        Stream1.ReadBuffer(buf^,rlen)  ;
        Stream2.Position:=Stream2.Size;
        Stream2.Write(buf^,rlen) ;

        Memo1.Lines.Clear;
        Memo1.Lines.Add('Copied: '+IntToStr(Stream2.Size)) ;
        Memo1.Lines.Add('Count:  '+IntToStr(Stream1.Size)) ;

        //free memory for buffer
        FreeMem(buf);


        If Stream2.Size=Stream1.Size then
        begin
         Memo1.Lines.Clear;
         Memo1.Lines.Add('Complete!') ;
         Memo1.Lines.Add('Please check cache of files!') ;
         exit;
        end;
      finally
        Stream2.Free;//WinAPI: CloseHandle
      end;
    finally
      Stream1.Free;//WinAPI: CloseHandle
    end;
    pos:=pos+bufsize;
    Application.ProcessMessages;
    goto m;
  end;
except
 on e:Exception do
 Memo1.Text:='ERR: '+e.Message;
end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
ShowMessage('Author: Burshtyn Nikolay. Special for ReactOS project.');
end;

end.