how to convert old strings in unicode

[HobbyDev]

Hi there,
its almost 10 years ago I stopped programming in Delphi and now I want to start in Lazarus again. Back in these days I wrote an application to store the information of my Mini-DV video tapes. The video directory contains a list of tapes where each tape has a list of titles which holds all scenes in a list belonging to that title. Every scenes is stored as an MKV file. Because I am using digiKam now to archive all information I don't need my old application any more. But I want to keep the information. So I thought to store the MKV's in the file structure where e.g. the title is a folder. And I want to store the scene's description inside the MKV using ffmpeg. And here is the point where I got lost: the conversion from old string into the new unicode world - at least for me it is new :-). When I do read the old strings they have the "?" sign where ever I used one of the German special characters like ÄäÖöÜüß and I don't know how to convert it so I can use it as e.g. a folder name. This is the code I used to store the title information:

Code: Pascal  [Select][+][-]

1. procedure TTitel.Store(var FS : TFileStream);
2. var AnzahlItems : Integer;
3.     i, l        : Integer;
4.     ASzene      : TSzene;
5. begin
6.   AnzahlItems := pred(Szenenliste.Count);
7.   l := Length(Titel);
8.   FS.Write(l, SizeOf(l));
9.   FS.Write(Titel[1], l);
10.   FS.Write(AnzahlItems, SizeOf(AnzahlItems));
11.   for I := 0 to AnzahlItems do
12.     begin
13.       ASzene := TSzene(Szenenliste.Items[i]);
14.       ASzene.Store(FS);
15.     end;
16. end;

where Titel is defined in the TTitle class as a string.
Reading a titel is done with this method:

Code: Pascal  [Select][+][-]

1. Constructor TTitel.CreateFromStream(var FS : TFileStream; AParent : TTape);
2. var AnzahlItems : Integer;
3.     i,l         : Integer;
4.     ASzene      : TSzene;
5. begin
6.   inherited Create;
7.   Parent      := AParent;
8.   Szenenliste := TList.Create;
9.   FS.Read(l, sizeOf(l));
10.   SetLength(Titel, l);          // then the string itself
11.   FS.Read(Titel[1], l);
12.   FS.Read(AnzahlItems, sizeOf(AnzahlItems));
13.   for i := 0 to AnzahlItems do
14.     begin
15.       ASzene := TSzene.CreateFromStream(FS, Self);
16.       Szenenliste.Add(ASzene);
17.     end;
18.   if TCF then Parent.TCF := True;
19. end;
20.  

To visualize the titles I use a treeview component and add nodes with the title string. And these nodes contain the "?" signs I want to get rid of, but don't know how. I am pretty sure you know it right away 

Many thx. in advanced!

[Thaddy]

You can simply use implicate assignment.

Code: Pascal  [Select][+][-]

1. {$mode objfpc}{$H+}
2. var
3.   a:AnsiString = 'test';
4.   b:Unicodestring;
5. begin
6.   b:=a;
7. end.
8.  

Don't look for complications where there aren't any.

[Zoran]

Your strings are most probably encoded with win1252 codepage. So try using CP1252ToUTF8 from LConvEncoding unit:

Code: Pascal  [Select][+][-]

1. uses
2.   ..., LConvEncoding, ...
3.  
4. ...
5.  
6. begin
7.   inherited Create;
8.   Parent      := AParent;
9.   Szenenliste := TList.Create;
10.   FS.Read(l, sizeOf(l));
11.   SetLength(Titel, l);          // then the string itself
12.   FS.Read(Titel[1], l);
13.  
14.   Titel := CP1252ToUTF8(Titel); // insert this line and try
15.  
16.   FS.Read(AnzahlItems, sizeOf(AnzahlItems));
17.   for i := 0 to AnzahlItems do
18.     begin
19.       ASzene := TSzene.CreateFromStream(FS, Self);
20.       Szenenliste.Add(ASzene);
21.     end;
22.   if TCF then Parent.TCF := True;
23. end;

[ASerge]

Code: Pascal  [Select][+][-]

1. ...
2.   l := Length(Titel);
3.   FS.Write(l, SizeOf(l));
4.   FS.Write(Titel[1], l);
5. ...
6.   FS.Read(l, sizeOf(l));
7.   SetLength(Titel, l);          // then the string itself
8.   FS.Read(Titel[1], l);
9.  

In FPC, TStream has WriteAnsiString and ReadAnsiString methods with the same behavior as your code.

[HobbyDev]

How cool is that! 
I checked your idea - Zoran! Perfectly! I am sure the others will work as well but this solution looked that easy I checked it first
Thank you very much. I should have done this earlier and save a lot of time