文件分割算法

文件的分割和合并
unit mgr;interfaceuses
  Windows, Messages, SysUtils, Classes, Forms,
  StdCtrls,shlobj, Controls, Dialogs,shellapi;type
  TForm1 = class(TForm)
    GroupBox1: TGroupBox;
    Button1: TButton;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    Button3: TButton;
    GroupBox2: TGroupBox;
    ListBox1: TListBox;
    procedure Button1Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure SaveDialog1CanClose(Sender: TObject; var CanClose: Boolean);
    procedure ListBox1DblClick(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    fstream1:tfilestream;
    fstream2:tfilestream;
    list:tstrings;
    len:tstrings;
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.DFM}
const
  flen=136192;  //请注意修改这儿的长度type
  FILE_INFO=record
    filename:array[0..MAX_PATH] of char;
    len:integer;
  end;function SelectDirectory(handle:hwnd;const Caption: string; const Root: WideString;out Directory: string): Boolean;
var
  lpbi:_browseinfo;
  buf:array [0..MAX_PATH] of char;
  id:ishellfolder;
  eaten,att:cardinal;
  rt:pitemidlist;
  initdir:pwidechar;
begin
  result:=false;
  lpbi.hwndOwner:=handle;
  lpbi.lpfn:=nil;
  lpbi.lpszTitle:=pchar(caption);
  lpbi.ulFlags:=BIF_RETURNONLYFSDIRS+BIF_EDITBOX;
  SHGetDesktopFolder(id);
  initdir:=pwchar(root);
  id.ParseDisplayName(0,nil,initdir,eaten,rt,att);
  lpbi.pidlRoot:=rt;
  getmem(lpbi.pszDisplayName,MAX_PATH);
  try
   result:=shgetpathfromidlist(shbrowseforfolder(lpbi),buf);
  except
   freemem(lpbi.pszDisplayName);
  end;
  if result then
  begin
   directory:=buf;
   if length(directory)<>3 then directory:=directory+'\';
  end;
end;procedure TForm1.Button1Click(Sender: TObject);
var
  info:FILE_INFO;
  i:integer;
  buf:array[0..4096] of byte;
  s:integer;
begin
  if savedialog1.Execute then
  if opendialog1.Execute then
  begin
    try
      copyfile(pchar(paramstr(0)),pchar(savedialog1.FileName),false);
      fstream1:=tfilestream.Create(pchar(savedialog1.FileName),fmopenreadwrite);
      fstream1.Seek(flen,soFromBeginning);
      for i:=0 to opendialog1.Files.Count-1 do
      begin
        strpcopy(info.filename,extractfilename(opendialog1.files.strings[i]));
        fstream2:=tfilestream.Create(opendialog1.Files.Strings[i],fmopenread);
        info.len:=fstream2.Size;
        fstream1.Write(info,sizeof(info));
        while fstream2.Position<>fstream2.Size do
        begin
        s:=fstream2.Read(buf,sizeof(buf));
        fstream1.Write(buf,s);
        end;
        fstream2.Free;
      end;
    finally
      fstream1.Free;
    end;
  end;
end;procedure TForm1.Button3Click(Sender: TObject);
var
  f:textfile;
  info:FILE_INFO;
  i:integer;
  buf:array[0..4096] of byte;
  s:integer;
  count,b:integer;
  dir:string;
begin
if selectdirectory(handle,'选择输出文件夹','',dir) then
   try
      fstream1:=tfilestream.Create(paramstr(0),fmShareDenyWrite);
      fstream1.Seek(flen,soFromBeginning);
      while fstream1.Position<>fstream1.Size do
      begin
        fstream1.Read(info,sizeof(info));
        count:=0;
        assignfile(f,dir+info.filename);
        rewrite(f);
        closefile(f);
        fstream2:=tfilestream.Create(dir+info.filename,fmopenwrite);
        fstream2.Size:=0;
        i:=info.len div sizeof(buf);
        for b:=1 to i do
        begin
        s:=fstream1.Read(buf,sizeof(buf));
        fstream2.Write(buf,s);
        inc(count,s);
        end;
        s:=fstream1.Read(buf,info.len-count);
        fstream2.Write(buf,s);
        fstream2.Free;
      end;
    finally
      fstream1.Free;
  end;
end;procedure TForm1.FormCreate(Sender: TObject);
var
  info:FILE_INFO;
begin
   list:=tstringlist.Create;
   len:=tstringlist.Create;
   try
      fstream1:=tfilestream.Create(paramstr(0),fmShareDenyWrite);
      fstream1.Seek(flen,soFromBeginning);
      while fstream1.Position<>fstream1.Size do
      begin
        fstream1.Read(info,sizeof(info));
        list.Add(inttostr(fstream1.position));
        len.Add(inttostr(info.len));
        listbox1.Items.Add(info.filename);
        fstream1.Seek(info.len,soFromCurrent);
      end;
    finally
      fstream1.Free;
  end;
  if listbox1.Items.Count>0 then button3.Enabled:=true else button3.Enabled:=false;
end;procedure TForm1.SaveDialog1CanClose(Sender: TObject;
  var CanClose: Boolean);
var
  f:integer;
begin
  f:=filecreate(savedialog1.FileName);
  if f<=0 then
  begin
    MessageBox(handle,'不能选择输出到该文件！',pchar(application.Title),MB_OK+MB_ICONerror);
    canclose:=false;
  end;
  fileclose(f);
end;procedure TForm1.ListBox1DblClick(Sender: TObject);
var
  path:array[0..max_path] of char;
  filename:string;
  f,b,s,count:integer;
  buf:array[0..4096] of char;
begin
  if button3.Enabled=false then exit;
  gettemppath(Max_path,path);
  filename:=path+listbox1.Items.Strings[listbox1.itemindex];
  fstream1:=tfilestream.Create(paramstr(0),fmShareDenyWrite);
  f:=filecreate(filename);
  fileclose(f);
  count:=0;
  fstream2:=tfilestream.Create(filename,fmopenwrite);
  fstream1.Seek(strtoint(list.Strings[listbox1.ItemIndex]),sofrombeginning);
  f:=strtoint(len.Strings[listbox1.itemindex]) div sizeof(buf);
  for b:=1 to f do
  begin
    s:=fstream1.Read(buf,sizeof(buf));
    fstream2.Write(buf,s);
    inc(count,s);
  end;
  s:=fstream1.Read(buf,strtoint(len.Strings[listbox1.itemindex])-count);
  fstream2.Write(buf,s);
  fstream2.Free;
  shellexecute(handle,'open',pchar(filename),'','',sw_show);
  fstream1.Free;
end;procedure TForm1.FormDestroy(Sender: TObject);
var
i:integer;
path:array[0..max_path] of char;
filename:string;
begin
  list.Free;
  len.Free;
  gettemppath(Max_path,path);
  for i:=0 to listbox1.Items.Count-1 do
  begin
    filename:=path+listbox1.Items.Strings[i];
    deletefile(filename);
  end;
end;end.

调试易

文件分割算法

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