std::string and unicode

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From: Marcin 'Malcom' Malich on 9 Apr 2008 05:27

---

On 9 Kwi, 11:00, "Declan McMullen" <declan.mcmul...(a)gmail.com> wrote:

> string Utility::wx2std(wxString s)
> {
>     char * newString = NULL;
>     int length = s.Length();
>     newString = new char[length];
>     return strcpy( newString, (const char*)s.mb_str(wxConvUTF8) );
>
> }
>

memory leak

std::string Utility::wx2std(wxString s)
{
return std::string(s.mb_str(wxConvUTF8), s.Length());
}

--
malcom
http://malcom.pl

From: Milan Babuskov on 9 Apr 2008 06:12

---

Declan McMullen wrote:
> Any tips on how I should do it ?

We are using the following in FlameRobin:

//-----------------------------------------------------------------------------
std::string wx2std(const wxString& input, wxMBConv* conv = 0)
{
if (input.empty())
return "";
if (!conv)
conv = wxConvCurrent;
const wxWX2MBbuf buf(input.mb_str(*conv));
// conversion may fail and return 0,
// which isn't a safe value to pass
// to std:string constructor
if (!buf)
return "";
return std::string(buf);
}
//-----------------------------------------------------------------------------
wxString std2wx(const std::string& input, wxMBConv* conv = 0)
{
if (input.empty())
return wxEmptyString;
if (!conv)
conv = wxConvCurrent;
return wxString(input.c_str(), *conv);
}
//-----------------------------------------------------------------------------

Any comments are appreciated.

--
Milan Babuskov
http://www.flamerobin.org

From: Robert Roebling on 9 Apr 2008 07:07

---

Marcin 'Malcom' Malich wrote:
>
> Declan McMullen wrote:
>
> > string Utility::wx2std(wxString s)
> > {
> > char * newString = NULL;
> > int length = s.Length();
> > newString = new char[length];
> > return strcpy( newString, (const char*)s.mb_str(wxConvUTF8) );
> >
> > }
> >
>
> memory leak
>
> std::string Utility::wx2std(wxString s)
> {
> return std::string(s.mb_str(wxConvUTF8), s.Length());
> }

wxString::Length() returns the number characters in the
unconverted string, not the number of bytes so this will
only work for ASCII characters. Why don't you simply use:

wxString s1 = "test";
std::string s2 = s1.utf8_str();
// or
std::wstring s2 = s1.wc_str();

or is there something wrong with this?

Robert

From: Milan Babuskov on 10 Apr 2008 05:21

---

Vadim Zeitlin wrote:
> MB> //-----------------------------------------------------------------------------
> MB> std::string wx2std(const wxString& input, wxMBConv* conv = 0)
> MB> {
> MB> if (input.empty())
> MB> return "";
> MB> if (!conv)
> MB> conv = wxConvCurrent;
> MB> const wxWX2MBbuf buf(input.mb_str(*conv));
> MB> // conversion may fail and return 0,
> MB> // which isn't a safe value to pass
> MB> // to std:string constructor
> MB> if (!buf)
> MB> return "";
> MB> return std::string(buf);
> MB> }
> MB> //-----------------------------------------------------------------------------
> MB> wxString std2wx(const std::string& input, wxMBConv* conv = 0)
> MB> {
> MB> if (input.empty())
> MB> return wxEmptyString;
> MB> if (!conv)
> MB> conv = wxConvCurrent;
> MB> return wxString(input.c_str(), *conv);
> MB> }
> MB> //-----------------------------------------------------------------------------
> MB>
> MB> Any comments are appreciated.
>
> This code is correct although I'm not sure why do you think it's necessary
> to test for empty string explicitly, normally you should be able to remove
> the checks for input.empty() without any ill effects.

We used to have some more complex code that allocated buffers and such,
so if string is empty it seemed efficient to not do all that. I guess it
could be removed now.

Thanks,

--
Milan Babuskov
http://www.flamerobin.org

From: Declan McMullen on 11 Apr 2008 04:20

---

Cheers for that.

Could you tell me what the second parameter is doing? And should I be
passing a value to it or leave it defaulting to 0 ?

On Wed, Apr 9, 2008 at 11:12 AM, Milan Babuskov <milanb(a)panonnet.net> wrote:

> Declan McMullen wrote:
>
> > Any tips on how I should do it ?
> >
>
> We are using the following in FlameRobin:
>
>
> //-----------------------------------------------------------------------------
> std::string wx2std(const wxString& input, wxMBConv* conv = 0)
> {
> if (input.empty())
> return "";
> if (!conv)
> conv = wxConvCurrent;
> const wxWX2MBbuf buf(input.mb_str(*conv));
> // conversion may fail and return 0,
> // which isn't a safe value to pass
> // to std:string constructor
> if (!buf)
> return "";
> return std::string(buf);
> }
>
> //-----------------------------------------------------------------------------
> wxString std2wx(const std::string& input, wxMBConv* conv = 0)
> {
> if (input.empty())
> return wxEmptyString;
> if (!conv)
> conv = wxConvCurrent;
> return wxString(input.c_str(), *conv);
> }
>
> //-----------------------------------------------------------------------------
>
> Any comments are appreciated.
>
> --
> Milan Babuskov
> http://www.flamerobin.org
>
> _______________________________________________
> wx-users mailing list
> wx-users(a)lists.wxwidgets.org
> http://lists.wxwidgets.org/mailman/listinfo/wx-users
>



--
http://www.computing.dcu.ie/~dmcmullen
declan.mcmullen(a)computing.dcu.ie
School of Computing
Postgrad Bay A

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