The String class doesn't work correctly with Russian

General JUCE discussion
1

Looks like the String class doesn't work correctly with Russian. A piece of code below:

#define tr(s) String::fromUTF8(s)
//---------------------------------------------------------------------
String sWord = tr("Программирование");

AlertWindow::showMessageBox(AlertWindow::WarningIcon, sWord,
                            sWord.toLowerCase(),
                            tr("Принять"));
//---------------------------------------------------------------------

How it works:

Juce Alert Window

 

Initial letters of both the caption and message are in upper case (expected lower case for message).

 

In the code below

#define tr(s) String::fromUTF8(s)
//---------------------------------------------------------------------
String sWord = tr("Программирование");
String sLetter = tr("п");

bool bYes = sWord.containsIgnoreCase(StringRef(sLetter));
//---------------------------------------------------------------------

the function containsIgnoreCase returns false (expected true).
 

Used JUCE versions: 4.1.0, 3.2.0

OS: Linux (Kubuntu 14.04.3 LTS)

Compiler: g++ 4.8.4

 

 

2

You can use the introjucer for creating a UTF8 String Literal. just launch it and go to Tools > UTF-8 String Literal

for what is worth your string becomes with it:

​
Программирование

CharPointer_UTF8 ("\xd0\x9f\xd1\x80\xd0\xbe\xd0\xb3\xd1\x80\xd0\xb0\xd0\xbc\xd0\xbc\xd0\xb8\xd1\x80\xd0\xbe\xd0\xb2\xd0\xb0\xd0\xbd\xd0\xb8\xd0\xb5")
3

I thought the same at first, but this shouldn’t be a problem if the source code is in UTF8 (although using a string literal would be safer).
I rather think that strcasecmp, which seems to be used on linux for the comparison, doesn’t work with cyrillic upper/lower case letters.

4

Hmm. Thanks for letting me know.. I've tweaked it now so that I think it should handle unicode better on all platforms.

5

Yes, I know this tool in the Introjucer. smiley

I won't write that it is very inconvenient for me to see UTF8 literals instead of normal letters. But! Unfortunately, the method juce_wchar CharPointer_UTF8::toLowerCase() const doesn't work correctly with Russian either.

A piece of code:

sWord = CharPointer_UTF8("\xd0\x9f\xd1\x80\xd0\xbe\xd0\xb3\xd1\x80\xd0\xb0\xd0\xbc\xd0\xbc\xd0\xb8\xd1\x80\xd0\xbe\xd0\xb2\xd0\xb0\xd0\xbd\xd0\xb8\xd0\xb5");

    AlertWindow::showMessageBox(AlertWindow::WarningIcon, sWord,
                                sWord.toLowerCase(),
                                CharPointer_UTF8("\xd0\x9f\xd1\x80\xd0\xb8\xd0\xbd\xd1\x8f\xd1\x82\xd1\x8c"));

Result the same:

Juce Alert Window

6

You know that that method only returns the first character of the string, as a lower case char, right?

If you want to convert a whole string to lower case, then you'd need to put it into a String first, otherwise there's no way that a bare wrapper class like CharPointer_UTF8 could allocate memory for the result.

7

Ah! Thank you. But I've just tried to put a CharPointer_UTF8 into the String and then call the toLowerCase method. Alas - the result was a described above.

8

Hmm, I don't think that is a platform-dependent problem. The result of the above code's execution in MS Visual Studio:

Juce Alert Window

 

Juce version: 3.2.0

OS: Windows 8.1

Compiler: MS Visual Studio Express 2013

 

9

Did you try it after the fix that I did for it this afternoon?

10

I've just tried again with the newly loaded github version of the JUCE.

Code:

#define tr(s) String::fromUTF8(s)
//---------------------------------------------------------------------
String sWord = tr("АаБбВвГгДд");

AlertWindow::showMessageBox(AlertWindow::WarningIcon, sWord,
                            sWord.toLowerCase(),
                            tr("Принять"));
//---------------------------------------------------------------------

Result:

Juce Alert Window

11

Привет, Dr_Andrew! Очень рад видеть здесь русскоязычных пользователей JUCE!

The problem that you are seeing is actually expected behaviour if you look at the C++ standard. Unfortunately, C++ doesn't really do unicode, so that is the underlying problem here. As a consequence, there is no language-agnostic unicode lowercase conversion in C++, either.

The method String::toLowerCase(), that you are calling here, calls CharacterFunctions::toLowerCase() under the hood, which is implemented by calling std::towlower (defined in header <cwctype>).

std::towlower is defined as follows in the C++ standard:

"towlower (ch) returns the lowercase version of ch, or unmodified ch if no lowercase version is listed in the current C locale."

So you see, you can only convert those characters to lowercase that are in the current C locale that your app has set. It is impossible to convert any character to lowercase that corresponds to an uppercase in any language supported by Unicode. For that, you'd need to use a proper 3rdparty unicode library, which we don't do in JUCE at the moment as they are big, complicated, and slow things down a lot.

As a workaround, you can manually set the C locale to Russian in your app. After this, the conversion will start working.

On OSX or Linux, you can get the available locales by typing 'locale -a' on the Terminal. For example, on my MacBook it lists a locale "ru_RU.UTF-8". (On Windows there is another way to get the names of the available locales I guess.)

Now, if I take your code and just add this:

#include <clocale>
std::setlocale (LC_ALL, "ru_RU.UTF-8");

then your code works as you intend.

I know it's an ugly workaround, but please believe me it is an incredibly complex problem to implement it properly...

Hope this helps.

 

P.S. I should add that std::setlocale is not always safe to call from an app and can have nasty side effects because the locale setting always affects the whole process you run. For example, if you do that in an audio-plugin, you can mess up the host (or even crash it -- seen it happening!) because it's running in the same process.

12

...or get a JUCEy modern alternative. :troll:

13

This is just embarrassing. So JUCE doesn’t do case with non ASCII. The lousy UTF support is a constant PITA.