On Tue, 28 Feb 2006 18:08:34 +0200
"Panagiotis Sidiropoulos" <[EMAIL PROTECTED]> wrote:
> For anyone interest on a UTF8Pos function, here is one as suggested by
> Vincent and Mattias:
>
> // Find position into a utf string
> function UTF8Pos( cSearcFor, cSearchInto: UTF8String ): integer;
> var
> nPos: integer;
>
> begin
> nPos := pos( cSearcFor, cSearchInto );
> if nPos > 0 then Result := UTF8Length( copy( cSearchInto, 1, nPos
> - 1 ) )
>
> else Result := 0;
> end;
Better use PChar for speed.
I added the following two function to LCLProc:
function UTF8Pos(const SearchForText, SearchInText: string): integer;
// returns the character index, where the SearchForText starts in
SearchInText
var
p: LongInt;
begin
p:=System.Pos(SearchForText,SearchInText);
if p>0 then
Result:=UTF8Length(PChar(SearchInText),p-1)+1
else
Result:=0;
end;
function UTF8Copy(const s: string; StartCharIndex, CharCount: integer):
string;
// returns substring
var
StartBytePos: PChar;
EndBytePos: PChar;
MaxBytes: PtrInt;
begin
StartBytePos:=UTF8CharStart(PChar(s),length(s),StartCharIndex-1);
if StartBytePos=nil then
Result:=''
else begin
MaxBytes:=PtrInt(PChar(s)+length(s)-StartBytePos);
EndBytePos:=UTF8CharStart(StartBytePos,MaxBytes,CharCount);
if EndBytePos=nil then
Result:=copy(s,StartBytePos-PChar(s)+1,MaxBytes)
else
Result:=copy(s,StartBytePos-PChar(s)+1,EndBytePos-StartBytePos);
end;
end;
Mattias
>
> Now, I'm trying to write a UTF8Copy function to return a specific
> ammount of characters (not bytes) from a string. Here is what I've done
> till now. It does not work correctly. Do you think I'm in the right path
> or is there any other, smarter, way to do this?
>
> // Get a utf character at a specific position
> function UTF8Copy( cCopyFrom: UTF8String; nFromPosition, nNoOfChars:
> integer ): UTF8String;
> var
> i,
> nUTF8Len,
> nByteLen,
> nStart: integer;
>
> begin
> Result := '';
> nUTF8Len := UTF8Length( cCopyFrom );
> if nFromPosition > nUTF8Len then exit;
>
> nByteLen := Length( cCopyFrom );
> nStart := 0;
> for i := 1 to nByteLen do begin
>
> if UTF8Length( copy( cCopyFrom, 1, i ) ) = nFromPosition then
> nStart := i + 1;
> if ( nStart > 0 ) and
> ( UTF8Length( copy( cCopyFrom, nStart, i ) ) = nNoOfChars )
> then break;
>
> end;
maybe better:
var
pCopyFrom
pCopyFrom:=UTF8CharStart(PChar(cCopyFrom),length(cCopyFrom),nFromPosition-1
);
if
> Result := copy( cCopyFrom, nStart, i );
> end;
>
> Panagiotis
>
> -----Original Message-----
> From: Mattias Gaertner [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, February 28, 2006 12:24 PM
> To: [email protected]
> Subject: Re: [lazarus] String functions on non latin text
>
>
> On Tue, 28 Feb 2006 09:57:09 +0200
> "Panagiotis Sidiropoulos" <[EMAIL PROTECTED]> wrote:
>
> > >so if there is something wrong with the sample I thought it should
> > >be gtk2 and the only problem I found was the position returned
> > >mismatched visually the substring
> >
> > I tried to find a relation between results but there is no any kind of
>
> > pattern, for example, for the first character give 1, the second 3 and
>
> > 21st give 41. Visually mismatch is the problem, I need to rearrange
> > characters for indexing reasons and can't trace what character is what
>
> > into convertion table.
>
> Jesus is right.
> UTF8 is a multi byte character encoding. This means a character has a
> size varying between 1 to 4. To get the character position use:
>
> BytePos:=System.Pos(search,text);
> if BytePos>0 then
> CharPos:=UTF8Length(Pchar(text),BytePos-1)
> else
> CharPos:=0;
>
>
> Mattias
>
>
> >
> > I will try to update Lazarus and FPC, just to be sure.
> >
> > Panagiotis
> >
> > -----Original Message-----
> > From: Jesus Reyes [mailto:[EMAIL PROTECTED]
> > Sent: Tuesday, February 28, 2006 8:30 AM
> > To: [email protected]
> > Subject: Re: [lazarus] String functions on non latin text
> >
> >
> >
> > ----- Original Message -----
> > From: "Mattias Gaertner" <[EMAIL PROTECTED]>
> > To: <[email protected]>
> > Sent: Monday, February 27, 2006 2:45 PM
> > Subject: Re: [lazarus] String functions on non latin text
> >
> >
> > > On Mon, 27 Feb 2006 13:41:13 -0600 (CST)
> > > Jesus Reyes <[EMAIL PROTECTED]> wrote:
> > >
> > > >
> > > > --- Panagiotis Sidiropoulos <[EMAIL PROTECTED]> escribió:
> > > >
> > > > > Please download sample project at:
> > > > > - www.magentadb.gr/ftp/pos-sample.zip
> > > > >
> > > > > Panagiotis
> > > > >
> > > >
> > > > result := Pos(UTF8Decode(SubStr), UTF8Decode(Str));
> > > >
> > > > seems to work, I think Pos(UTF8String,UTF8String) is yet to be
> > > > implemented.
> > >
> > > It does not need to be implemented. One nice feature of UTF8 is,
> > > that
> > > you can find out the start of an UTF8 character without parsing the
> > > whole string. A simple substring search works with UTF8 and is
> > > unambiguous.
> >
> > I guess it would depend on the need for the pos function return value,
>
> > if some feedback should be made to the user about the position the
> > substring matched then current pos functions doesn't not return a
> > visually right position, I mean
> > counting characters form left to right, the correct position should
> be
> > 21 not 41.
> >
> > If the value is to be user with other string functions then the return
>
> > value is right.
> >
> > if the function is ever implemented I think it should be for something
>
> > like
> > pos(UTFString,UTFString) where UTFString should represent any UTF
> > Encoding in use. Unlikely? maybe :D
> >
> > > On the other hand: UTF8Decode will fail on some character sets, not
> > > fitting into 2byte characters.
> >
> > it seems to have support for at least 3 byte chars. I didn't test
> > tho..
> >
> > >
> > > My guess, why a simple Pos does not work for Panagiotis, is a either
>
> > > a
> >
> > > FPC bug or a gtk1 bug with greek characters.
> > >
> >
> > I compiled the test first for gtk1 and results looked right to me, so
> > if there is something wrong with the sample I thought it should be
> > gtk2 and the only problem I found was the position returned mismatched
>
> > visually the substring
> >
> > >
> > > Mattias
> > >
> >
> > Jesus Reyes A.
> >
> > __________________________________________________
> > Correo Yahoo!
> > Espacio para todos tus mensajes, antivirus y antispam ¡gratis!
> > Regístrate ya - http://correo.yahoo.com.mx/
> >
> > _________________________________________________________________
> > To unsubscribe: mail [EMAIL PROTECTED] with
> > "unsubscribe" as the Subject
> > archives at http://www.lazarus.freepascal.org/mailarchives
> >
> > _________________________________________________________________
> > To unsubscribe: mail [EMAIL PROTECTED] with
> > "unsubscribe" as the Subject
> > archives at http://www.lazarus.freepascal.org/mailarchives
>
> _________________________________________________________________
> To unsubscribe: mail [EMAIL PROTECTED] with
> "unsubscribe" as the Subject
> archives at http://www.lazarus.freepascal.org/mailarchives
>
> _________________________________________________________________
> To unsubscribe: mail [EMAIL PROTECTED] with
> "unsubscribe" as the Subject
> archives at http://www.lazarus.freepascal.org/mailarchives
_________________________________________________________________
To unsubscribe: mail [EMAIL PROTECTED] with
"unsubscribe" as the Subject
archives at http://www.lazarus.freepascal.org/mailarchives
