[Lazarus] cwstring in arm-linux

Hans-Peter Diettrich DrDiettrich1 at aol.com
Fri Oct 21 23:48:25 CEST 2011


Ċ½ilvinas Ledas schrieb:
> Hello,
> 
> On 2011-10-21 10:43, Michael Schnell wrote:
>> Of course you are right, but "move" and friends is "hardware-near 
>> programming" for this who know what they are doing. but basic (legacy) 
>> string operations like "myChar := myString[i]" is "office-level 
>> programming" and thus should work as a dummy expects.
>>
> 
> What if a file on the user computer has 4byte [visible] character as 8th 
> character and you, for example want to get 8 character file name? In 
> this case you split that 4 byte character and have garbage.

Then you (or your boss) didn't understand the meaning of "4 characters". 
(Logical) characters are different from physical Chars, in every MBCS 
codepage.

> What it user inputs in your text field (or a command line parameter or 
> anywhere else) a string containing 4 byte character and you split that 
> string on that character? (For example when showing some kind of summary 
> of his input.) Don't forget that user can input characters by 
> copy-pasting them from the web, not only using his keyboard!

See above. With proportial fonts, counting characters is a bad idea, 
instead the width of the displayed string (in pixels) should be used. 
Then you also can deal with languages and character sets, which use 
ligatures and the like. Even with monospaced fonts the "characters" 
(glyphs) can have a different width, in multiples of the basic width, 
e.g. for Chinese or other eastern character sets.

> So, if you want to write PROFESSIONAL software with any user input - you 
> must handle 4 byte characters at every place you get user input.

Counting characters then is a bad idea, see above.

> Otherwise you leave a chance to get and show to the user garbage. Is 
> this really easier than using UTF8 everywhere?
> 
> My personal experience: I am maintaining (as a hobby project) 
> multi-language dictionary program (a screen-shoot: 
> http://2.bp.blogspot.com/_3-IaodGIbVQ/TMHY-l9M4sI/AAAAAAAAAak/AbtShWq0ZUQ/s1600/KZod_screen_win7.png

Great :-)

> ) and it involves quite a bit of [multilingual] string manipulation and 
> when I did migration from delphi to Lazarus I didn't know about 
> requirement that all (GUI) strings must be UTF8 and I had no problems 
> migrating! Yes, afterwards I tweaked some calls to RTL (mostly file 
> handling) functions that expected to get ANSI encoding, but this is not 
> a problem of UTF8, but or RTL being (mostly) ansi.

 From which Delphi version did you migrate?
What encoding did you use in Delphi?

DoDi





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