JUCE_STRING_UTF_TYPE 32 build errors

General JUCE discussion
1

Jules: "Damn, it's that UTF-32 guy again..."

Some default args in juce_XmlElement.h (StringRef encodingType = "UTF-8"):

cannot convert from 'const char [6]' to 'juce::StringRef'
2

Damn, it's you again.

I'll fix it, but did I ever ask why you're actually using that mode?

While doing some string work lately, I was trying to think of any situation where utf8 wouldn't be the best option, but couldn't think of one. I guess if you were doing a ton of time-critical win32 string calls, then just maybe you could make a vague argument for using utf16, but utf32..??

3

BTW I should mention that the only way to fix these errors involves disabling the new StringRef class in UTF-32 builds, so many more string copies will end up being made wherever a string literal is involved.

I really do recommend sticking with utf-8 unless you've profiled your app and actually measured its performance to be better. Seems highly unlikely to me that it'd ever be better to use the other encodings.

4

I'm doing multiple time-critical processing steps on potentially very large strings. Using UTF-32 is allowing me to avoid converting as well as allocating memory to cache a converted string to pass to different systems. I need to take every performance increase I can get.

5

Ok, fair enough!

6

I don't have those errors I mentioned anymore but now there are others. Something about ambiguous constructor or something. Not really sure what's going on as I see there are conversion operators in there. Adding a StringRef to a const String& also appears to be completely confusing the compiler in some instances.

7

If you can give me some examples, I'll see if there's anything I can add to help the compiler figure it out.

8

juce_File.cpp line 359: juce::String + juce::StringRef

'juce::String::operator bool' : cannot access private member declared in class 'juce::String'

 

juce_File.cpp line 649: juce::String + juce::StringRef

cannot convert parameter 1 from 'juce::CharPointer_UTF32::CharType' to 'juce::StringRef'

 

juce_StringArray.cpp line 198: 

'bool juce::String::equalsIgnoreCase(const juce::String &) throw() const' : cannot convert parameter 1 from 'juce::StringRef' to 'const juce::String &'

 

I can make it build and work by adding this to StringRef:

operator const String&() const noexcept                             { return stringCopy; }

 

I also had to modify the constructors for StringRef so that they populate StringRef::stringCopy and give its pointer to StringRef::text for that to work properly (juce_String.cpp line 2090). 


StringRef::StringRef (String::CharPointerType stringLiteral) noexcept
   #if JUCE_STRING_UTF_TYPE != 8
    : text (nullptr), stringCopy (stringLiteral)
   #else
    : text (stringLiteral)
   #endif
{
   #if JUCE_STRING_UTF_TYPE != 8
    text = stringCopy.getCharPointer();
   #endif
    jassert (stringLiteral.getAddress() != nullptr); // This must be a valid string literal, not a null pointer!!
}
StringRef::StringRef (const String& string) noexcept
    #if JUCE_STRING_UTF_TYPE != 8
    : text (nullptr), stringCopy (string)
   #else
    : text (string.getCharPointer())
   #endif
{
   #if JUCE_STRING_UTF_TYPE != 8
    text = stringCopy.getCharPointer();
   #endif
}
9

Ah, is this Visual Studio? I did test building it in UTF32 mode, but only with LLVM.. I'll check it with VC.

10

I'm using Visual Studio 2012.