diff options
Diffstat (limited to 'rational.c')
| -rw-r--r-- | rational.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/rational.c b/rational.c index f0e8d56cbf..8362075ab4 100644 --- a/rational.c +++ b/rational.c @@ -1250,7 +1250,7 @@ nurat_truncate(VALUE self) } static VALUE -nurat_round(VALUE self) +nurat_round_half_up(VALUE self) { VALUE num, den, neg; @@ -1274,6 +1274,33 @@ nurat_round(VALUE self) } static VALUE +nurat_round_half_even(VALUE self) +{ + VALUE num, den, neg, qr; + + get_dat1(self); + + num = dat->num; + den = dat->den; + neg = f_negative_p(num); + + if (neg) + num = f_negate(num); + + num = f_add(f_mul(num, TWO), den); + den = f_mul(den, TWO); + qr = rb_funcall(num, rb_intern("divmod"), 1, den); + num = RARRAY_AREF(qr, 0); + if (f_zero_p(RARRAY_AREF(qr, 1))) + num = rb_funcall(num, '&', 1, LONG2FIX(((int)~1))); + + if (neg) + num = f_negate(num); + + return num; +} + +static VALUE f_round_common(int argc, VALUE *argv, VALUE self, VALUE (*func)(VALUE)) { VALUE n, b, s; @@ -1403,7 +1430,14 @@ nurat_truncate_n(int argc, VALUE *argv, VALUE self) static VALUE nurat_round_n(int argc, VALUE *argv, VALUE self) { - return f_round_common(argc, argv, self, nurat_round); + VALUE opt; + enum ruby_num_rounding_mode mode = ( + argc = rb_scan_args(argc, argv, "*:", NULL, &opt), + rb_num_get_rounding_option(opt)); + VALUE (*round_func)(VALUE) = + ROUND_TO(mode, + nurat_round_half_up, nurat_round_half_even); + return f_round_common(argc, argv, self, round_func); } /* |