Circumventing RichEdit slowdown
Hello,
I've been intermittenly working on a syntax editor (in between
revamping the engine behind it) and I've gotten both to a reasonable
level. Functional, if not complete.
At the moment, I've used a RichEditCtrl as my editing window, and it's
been subclassed to provide all the syntax coloring I need. The syntax
coloring is somewhat faster than most I've found online, and is quite
transparent (I have the advantage of not having to recolor the entire
line each time, as I don't have multi-line comments, in fact, I only
have to recolor the word on the left and word on the right when the
user types.)
I have to be able to support moderately large files (our cripple case
is 2.1 million lines @ 69mb), and the control is intermittenly
terribly slow. So I threw in a condition to just turn off syntax
coloring if the file loading in was over a certain size, as I thought
that might be slowing it down (it makes some sense that grabbing
selections might be slower on large files).
However, it's still just as slow. It's not the coloring slowing it
down. I just tweaked my file loading (used to take ~ 20 minutes to
load in on my 'just get it working' approach) so the actual data
appears in the window within ~1sec (if unicode, I haven't tweaked ansi
loading), but then I have to wait about a 30 seconds to a minute
before I can interact with my modeless dialog again (and indeed,
before it even updates the scrollbars). What's happening there?
Stepping through the code doesn't reveal anything. Is this overhead
in the rich edit itself, or does this sound like I am I unknowingly
tripping something up in my own code?
In my loader, after opening the file (yes, I'm aware I don't have
error protection)
if (file != NULL)
{
try{
if (file.IsFileUnicodeText()){
_TCHAR *szBuffer = new
_TCHAR[file.GetCharCount()];
long mask = m_REditControl.GetEventMask();
m_REditControl.SetEventMask(mask &
~ENM_CHANGE );
file.Read(szBuffer, file.GetCharCount());
m_progbarcontrol.SetPos(100);
m_REditControl.SetWindowText(szBuffer);
m_REditControl.SetEventMask(mask |
ENM_CHANGE );
m_REditControl.SetModify(false);
delete szBuffer;
}
else{
Total.GetBuffer(len); //Good initial guess.
char *szBuffer = new
char[file.GetCharCount()];
long mask = m_REditControl.GetEventMask();
m_REditControl.SetEventMask(mask &
~ENM_CHANGE );
file.Read(szBuffer, file.GetCharCount());
m_progbarcontrol.SetPos(100);
CString temp;
mbstowcs(temp.GetBuffer(file.GetCharCount()),
szBuffer, file.GetCharCount());
m_REditControl.SetWindowText(temp);
m_REditControl.SetEventMask(mask |
ENM_CHANGE );
m_REditControl.SetModify(false);
delete szBuffer;
}
// if (nTotal > 0 && nTotal <= len)
// szBuffer[nTotal] = '\0';
}
catch(CFileException)
{
// read error
file.Close();
bReturn = false;
}
}
else
{
file.Close();
bReturn = false;
}
}
file.Close();
if (len > 65536)
{
m_REditControl.m_bColor = false;
}
}
else
bReturn = false;
m_REditControl.ReformatScreen();
return bReturn;
}
I took a look at my OnChange method and I have this check in: (again,
a hack fix, and if you know a better way to do this, please, let me
know.
long curLimit = this->GetLimitText(); <<strangely, curLimit did
not equal GetLimitText return value after this call
if (this->GetTextLength() == curLimit) <<took >10 seconds to do
this line
this->LimitText(curLimit + 1000);
What's slowing this down? Why does GetTextLength crawl? Does it not
keep an internal size parameter? Doesn't it HAVE to to be able to
check against its limit?
Any help you all have, or any experience, please share. Also, if you
can help me improve my loading routines, that would help greatly (I
won't take offense). I just noticed they are putting a bit of garbage
at the end of large files. IsFileUnicodeText is a non-standard method
that checks the byte-order mark of the file for a unicode mark. Not
ALL unicode files have them, but any that are created with my editor
do.