In the past, the source code has been first in CVS repository on SourceForge, then in Subversion repository on SourceForge, and then in Bazaar repository on SourceForge. The code has been moved to Launchpad.net because SourceForge has stopped supporting Bazaar as a first class citizen.
Anybody can contribute to log4cplus development. If you are contributing a source code change, use a reasonable form: a merge request of a Bazaar branch or a patch file attached to a ticket in Bugs tracker or sent to log4cplus-devel mailing list. Unless it is obvious, always state what branch or release tarball is your patch based upon.
Please use common sense. Follow the style of surrounding code. You can use the following Emacs style that is based on Microsoft's style as a guide line:
;; Custom MS like indentation style. (c-add-style "microsoft" '("stroustrup" (c-offsets-alist (innamespace . -) (inline-open . 0) (inher-cont . c-lineup-multi-inher) (arglist-cont-nonempty . +) (template-args-cont . +))))