Abdelrazak Younes wrote:
> Helge Hafting wrote:
>> Abdelrazak Younes wrote:
>>> ucs4_to_qstring is pretty simple:
>>>
>>> QString const ucs4_to_qstring(char_type const * str, size_t ls)
>>> {
>>> QString s;
>>>
>>> for (size_t i = 0; i < ls; ++i)
>>> s.append(ucs4_to_qchar(str[i]));
>>>
>>> return s;
>>> }
>> A function call per character - ouch.
I would be more concerned about resizing by append(). Why don't you do this?
QString const ucs4_to_qstring(char_type const * str, size_t ls)
{
QString s;
s.reserve(ls);
for (size_t i = 0; i < ls; ++i)
s.append(ucs4_to_qchar(str[i]);
return s;
}
(assuming that QString has a reserve() member, I don't know)
> Note that this function doesn't show in Andre's profiling results. But I
> am going to inline it to see if there's a difference.
That shoudd probably be inlined.
>> Is it allowed to have a single function that understands
>> both ucs4 strings and QString?
>
> What do you mean?
>
>> Then the conversion could
>> be done in a single function. That tends to bring a nice speedup.
I guess Helge means
void ucs4_to_qstring(char_type const * str, size_t ls, QString & s)
That avoids one copy operation for non-shared strings, but since IIRC
qstrings are shared I don't expect a speedup here.
Georg
