Delphi - ExtractFileName messes up unicode

Question

I am using ExtractFileName of a WideString that equals to 'STF:宋体'. The result is '??'.

It seems that ExtractFileName does not handle unicode well.

Is there an equivalent method for unicode?

Edit:

This is the line i use

NameStr := ExtractFileName(Name);

the types are:

NameStr:String;

Name:PWideChar

ExtractFileName works perfectly with a Unicode Delphi. Which version are you using? — David Heffernan, Apr 05 '11 at 07:13
Tested in Delphi XE and got `宋体` when running `ShowMessage(ExtractFileName('STF:宋体'));` — Mikael Eriksson, Apr 05 '11 at 07:13
Not had any problems using ExtractFileName with Unicode file names. You do know that WideString <> UnicodeString (which is the Delphi string default)? Please show your code and especially the variable declarations, or we will just be stabbing in the dark. — Marjan Venema, Apr 05 '11 at 07:14
The question marks make me believe you're using a non-unicode string variable somewhere along the call (you get question marks for characters that can't be represented as AnsiString). You should step throw your code (using F7 - step into) and look at the code; You're probably not calling the `ExtractFileName` you expect! — Cosmin Prund, Apr 05 '11 at 07:19

Ondrej Kelle · Accepted Answer · 2011-04-05T08:15:18.507

4

You can also use TntSysUtils.WideExtractFileName from TNT.

edited Apr 05 '11 at 08:15

answered Apr 05 '11 at 08:01

Ondrej Kelle

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score 1 · Answer 2 · answered Apr 05 '11 at 07:28

1

You appear to be using an old version of Delphi without support for Unicode. The solution is to upgrade Delphi.

answered Apr 05 '11 at 07:28

David Heffernan

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You are correct - i am using Delphi 2006. Upgrading the version is not an option at this point (can't take the risk). Is there a way to solve this issue without upgrade? – Erik Sapir Apr 05 '11 at 07:37
You'll have to roll your own versions of all string manipulation routines. If there are a lot then an upgrade would be the less risky. If there are only a handful then you might be alright. You'll need to stop using string (which is AnsiString) and stick to WideString. – David Heffernan Apr 05 '11 at 07:59

score 0 · Answer 3 · edited Nov 26 '13 at 11:39

0

Function ExtractFileNameW(const FN: widestring): widestring;
 begin
  Result := UTF8Decode(ExtractFileName(UTF8Encode(FN)));
 end;

edited Nov 26 '13 at 11:39

Aziz Shaikh

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answered Nov 26 '13 at 11:20

Krzysztof Jacewicz

1

score 0 · Answer 4 · answered Apr 05 '11 at 10:33

You can use a home-cooked version of ExtractFileName, like this:

function ExtractFileNameW(FullPath:WideString):WideString;
var i,pos:Integer;
begin
  // Find the last path separator
  pos := -1;
  for i:=Length(FullPath) downto 1 do
    if (FullPath[i] = '/') or (FullPath[i] = '\') then
    begin
      pos := i;
      Break;
    end;
  if pos = -1 then
    Result := FullPath
  else
    begin
  Result := '';
      SetLength(Result, Length(FullPath)  - pos);
      System.Move(FullPath[pos+1], Result[1], (Length(FullPath) - pos) * SizeOf(WideChar));
    end;
end;

... but if you really need to deal with Unicode characters you should upgrade to XE. It really makes a lot of difference.

Delphi - ExtractFileName messes up unicode

4 Answers4