unit ShellZip;

interface

 function NumProcessThreads: integer;
 function ShellZip(zipfile, sourcefolder:string; filter: string = ''): boolean;
 function ShellUnzip(zipfile, targetfolder: string; filter: string = ''): boolean;


implementation

uses Comobj, Windows,Tlhelp32;

const
  SHCONTCH_NOPROGRESSBOX = 4;
  SHCONTCH_AUTORENAME = 8;
  SHCONTCH_RESPONDYESTOALL = 16;
  SHCONTF_INCLUDEHIDDEN = 128;
  SHCONTF_FOLDERS = 32;
  SHCONTF_NONFOLDERS = 64;

function ShellUnzip(zipfile, targetfolder: string; filter: string = ''): boolean;
var
  shellobj: variant;
  srcfldr, destfldr: variant;
  shellfldritems: variant;
begin
  shellobj := CreateOleObject('Shell.Application');

  srcfldr := shellobj.NameSpace(zipfile);
  destfldr := shellobj.NameSpace(targetfolder);

  shellfldritems := srcfldr.Items;
  if (filter <> '') then
    shellfldritems.Filter(SHCONTF_INCLUDEHIDDEN or SHCONTF_NONFOLDERS or SHCONTF_FOLDERS,filter);

  destfldr.CopyHere(shellfldritems, SHCONTCH_NOPROGRESSBOX or SHCONTCH_RESPONDYESTOALL);
end;

function NumProcessThreads: integer;
var
  hsnapshot: THandle;
  Te32: TTHREADENTRY32;
  proch: dword;
  procthreads: integer;
begin
  procthreads := 0;

  proch := GetCurrentProcessID;

  hSnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);

  Te32.dwSize := sizeof(TTHREADENTRY32);

  if Thread32First(hSnapShot, Te32) then
  begin
    if te32.th32OwnerProcessID = proch then
      inc(procthreads);

    while Thread32Next(hSnapShot, Te32) do
    begin
      if te32.th32OwnerProcessID = proch then
        inc(procthreads);
    end;
  end;
  CloseHandle (hSnapShot);
  Result := procthreads;
end;

function ShellZip(zipfile, sourcefolder:string; filter: string = ''): boolean;
const
  emptyzip: array[0..23] of byte = (80,75,5,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
var
  ms: TMemoryStream;
  shellobj: variant;
  srcfldr, destfldr: variant;
  shellfldritems: variant;
  numt: integer;
begin
  if not FileExists(zipfile) then
  begin
    // create a new empty ZIP file
    ms := TMemoryStream.Create;
    ms.WriteBuffer(emptyzip, sizeof(emptyzip));
    ms.SaveToFile(zipfile);
    ms.Free;
  end;

  numt := NumProcessThreads;

  shellobj := CreateOleObject('Shell.Application');

  srcfldr := shellobj.NameSpace(sourcefolder);
  destfldr := shellobj.NameSpace(zipfile);

  shellfldritems := srcfldr.Items;

  if (filter <> '') then
    shellfldritems.Filter(SHCONTF_INCLUDEHIDDEN or SHCONTF_NONFOLDERS or SHCONTF_FOLDERS,filter);

  destfldr.CopyHere(shellfldritems, 0);

  // wait till all shell threads are terminated
  while NumProcessThreads <> numt do
  begin
    sleep(100);
  end;
end;

end.