On 23 February 2012 12:10, Gilles Sadowski <gil...@harfang.homelinux.org> wrote: > On Thu, Feb 23, 2012 at 11:32:54AM +0000, sebb wrote: >> On 23 February 2012 11:19, Gilles Sadowski <gil...@harfang.homelinux.org> >> wrote: >> > On Thu, Feb 23, 2012 at 10:55:51AM +0000, sebb wrote: >> >> On 16 February 2012 16:17, <l...@apache.org> wrote: >> >> > Author: luc >> >> > Date: Thu Feb 16 16:17:14 2012 >> >> > New Revision: 1245061 >> >> > >> >> > URL: http://svn.apache.org/viewvc?rev=1245061&view=rev >> >> > Log: >> >> > Removed unneeded clone. >> >> > >> >> > The clone did not protect the array used, only the reference ones. >> >> > JIRA: MATH-650 >> >> >> >> -1 >> >> >> >> That was the whole point of the clone - to protect the original external >> >> data. >> > >> > Please (re-)explain what you mean by "protect". Cf. my comment on the >> > JIRA page. >> >> See also your comment of 30/Nov/11 00:31. > > I know, but my latest comment overrides that one. > >> The arrays in FastMathLiteralArrays are private, but the access >> methods are not, and returning an array allows the caller to modify >> array elements. > > It's true, but unless I'm mistaken, it doesn't matter since in the end there > is one and only one array that will be _used_ (the modified one) and having > a pristine copy somewhere else will not prevent the dire consequences of > using the modified one... ;-/
Not sure I follow that. Without clone, the array entries can be changed at any time. With clone, there are two pristine copies; neither can be changed directly as they are stored in private arrays. >> If you don't want the memory overhead of a clone, then one could use >> array entry getters instead. > > It's not that: It is because "clone" gives a false sense of security. How so? Are you saying that someone can change the original array entries by accessing the cloned copy? > Yes, getters would be _really_ secure, as they would prevent an inadvertant > CM developer to commit a bug in the "FastMath" class. But a _user_ of > "FastMath" can anyways never access the arrays (as the references/copies are > "private" to "FastMath"), so I was wondering whether the additional layer of > security was really worth it (in case a performance loss would accompany the > getters; if not, then fine, fine). > > > Gilles > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
