[fpc-pascal] Comparing version numbers

[Felipe Monteiro de Carvalho]

On 6/2/06, Vincent Snijders <vsnijders at quicknet.nl> wrote:
> Split the version string in several numbers:
> version := '4.0.12';
> major := 4
> minor := 0;
> patch := 12;

I think this is the winner solution.

But you don´t have to do this:

> versionnumber := major * 10000 + minor * 100 + patch

It´s better to just do many ifs, something like this:

type
  TVersao = packed record
    TamanhoDaEstrutura: Cardinal;
    VersaoMaior: Integer;
    VersaoMenor: Integer;
    Distribuicao: Integer;
    Construcao: Integer;
    Patch: Integer;
  end;

function IsVersionBigger(Esperada, Ver: TVersion): Boolean;
begin
  Result := False;

  if Esperada.VersaoMaior < Ver.VersaoMaior then
   Result := True
  else if Esperada.VersaoMenor < Ver.VersaoMenor then
   Result := True
  else if Esperada.Distribuicao < Ver.Distribuicao then
   Result := True
  else if Esperada.Construcao < Ver.Construcao then
   Result := True
  else if Esperada.Patch <= Ver.Patch then
   Result := True;
end;

This supports up to 4 dots separating 5 version parts. Of course, you
can build a dynamic structure to hold any number of version parts and
then do a while to hold the any number of ifs.

-- 
Felipe Monteiro de Carvalho