I thought we had efforts to make String::operator+= use StringBuilder somehow? I can remember that we had a discussion on webkit-dev and definitely on bugzilla about improving String::operator+= instead of replacing it with StringBuilder.
Greetings, Dirk On Sep 4, 2012, at 4:22 PM, Adam Barth <[email protected]> wrote: > As part of the work to deploy efficient string patterns [1] throughout > WebKit, Benjamin and I noticed a bunch of very inefficient code that > uses operator+= with Strings: > > String foo; > for (...) > foo += [...]; > return foo; > > This pattern is particularly inefficient because += mallocs an > entirely new buffer for the result and copies the the string into the > new buffer. That means that this pattern makes O(n) calls to malloc > and does O(n^2) work. A more efficient pattern is to use > StringBuilder: > > StringBuilder foo; > for (...) > foo.append([...]); > return foo.toString(); > > I'm in the process of going through WebCore and removing all callers > of WTF::String::operator+=. Once that's complete, my plan is to > remove WTF::String::operator+= from WTFString.h. Hopefully that will > nudge contributors and reviewers towards more efficient string > patterns. > > Removing operator+= will likely require changes to a number of > port-specific files. I'll do my best to remove these, but I might > need some help from maintainers of individual ports. If you're > interested in helping out, please let me know. > > Many thanks, > Adam > > [1] http://trac.webkit.org/wiki/EfficientStrings > _______________________________________________ > webkit-dev mailing list > [email protected] > http://lists.webkit.org/mailman/listinfo/webkit-dev _______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo/webkit-dev
