Re: [PATCH] diff: round down similarity index

> On Mon, 25 Jun 2007, Ren� Scharfe wrote:
> 
> > Rounding down the printed (dis)similarity index allows us to use
> > "100%" as a special value that indicates complete rewrites and
> > fully equal file contents, respectively.
> >
> > [...]
> > 
> > +static int similarity_index(struct diff_filepair *p)
> > +{
> > +	int result = p->score * 100.0 / MAX_SCORE;
> > +
> > +	/* Paranoia: guard against floating point rounding errors. */
> > +	if (p->score == MAX_SCORE)
> > +		result = 100;
> > +	else if (result == 100)
> > +		result = 99;
> > +
> > +	return result;
> > +}
> 
> That's not even properly rounding down. The correct formula (correct in 
> the sense for "what you want") would be
> 
> 	p->score * 100.0 / MAX_SCORE
> 
> if p->score == MAX_SCORE, iff the files are identical. And yes, that is 
> the old formula.