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Graeme Geldenhuys <graemeg.lists@gmail.com> hat am 17. Februar 2011 um 10:35 geschrieben:<br/>
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> Op 2011-02-17 11:28, Michael Schnell het geskryf:<br/>
> > On 02/17/2011 07:19 AM, Jürgen Hestermann wrote:<br/>
> >><br/>
> >> I often search for substrings, delete them from the string, insert<br/>
> >> other strings at certain places, etc.<br/>
> >> How can you do all this without knowledge of the internal structure of<br/>
> >> the string?<br/>
> > This (magically :-) ) does work with UTF8.<br/>
><br/>
> NO, it doesn't! You can't use FPC's Copy(), Pos() etc reliably with<br/>
> UTF-8 text, because thouse RTL functions work purely on ANSI text<br/>
> (1-byte characters - speaking of String type text here) and don't know<br/>
> about multi-byte characters, combining diacritics etc.
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<p style="margin: 0px;">Yes, it does. UTF8Pos simply calls Pos and converts the byte position to code point.</p>
<p style="margin: 0px;">Pos works, because the first byte of an UTF-8 code point is distinct from the following (%111), so if you search for a valid UTF-8 string Pos will return a valid UTF-8 position. Of course this is a byte position.</p>
And since copy, insert and delete use byte positions as well you can use them together without trouble.<br/>
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> Hence LCL and fpGUI have special functions similar to RTL, that knows how to work with<br/>
> UTF-8 encoded text. eg: UTF8Pos(), UTF8Length and UTF8Copy() etc functions.
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They are useful when you must deal with code points. For example TEdit.SelStart and SelLength are in code points.<br/>
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Mattias<br/>
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