From 0229f70039a4eab72d3a007e4fde2af8935d750b Mon Sep 17 00:00:00 2001 From: nobu Date: Thu, 7 Jul 2016 07:37:55 +0000 Subject: numeric.c: round nearly middle value * numeric.c (flo_round): [EXPERIMENTAL] adjust the case that the receiver is close to the exact but unrepresentable middle value of two values in the given precision. http://d.hatena.ne.jp/hnw/20160702 git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55604 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- numeric.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'numeric.c') diff --git a/numeric.c b/numeric.c index c92b7b430b..b806ceca3c 100644 --- a/numeric.c +++ b/numeric.c @@ -1990,7 +1990,7 @@ rb_int_truncate(VALUE num, int ndigits) static VALUE flo_round(int argc, VALUE *argv, VALUE num) { - double number, f; + double number, f, x; int ndigits = 0; if (rb_check_arity(argc, 0, 1)) { @@ -2005,7 +2005,14 @@ flo_round(int argc, VALUE *argv, VALUE num) } if (float_invariant_round(number, ndigits, &num)) return num; f = pow(10, ndigits); - return DBL2NUM(round(number * f) / f); + x = round(number * f); + if (x > 0) { + if ((x + 0.5) / f <= number) x += 1; + } + else { + if ((x - 0.5) / f >= number) x -= 1; + } + return DBL2NUM(x / f); } static int -- cgit v1.2.3