diff --git a/rational.c b/rational.c index 626d29565e..0cba54e281 100644 --- a/rational.c +++ b/rational.c @@ -220,6 +220,26 @@ f_one_p(VALUE x) return rb_funcall(x, id_eqeq_p, 1, ONE); } +inline static VALUE +f_minus_one_p(VALUE x) +{ + switch (TYPE(x)) { + case T_FIXNUM: + return f_boolcast(FIX2LONG(x) == -1); + case T_BIGNUM: + return Qfalse; + case T_RATIONAL: + { + VALUE num = RRATIONAL(x)->num; + VALUE den = RRATIONAL(x)->den; + + return f_boolcast(FIXNUM_P(num) && FIX2LONG(num) == -1 && + FIXNUM_P(den) && FIX2LONG(den) == 1); + } + } + return rb_funcall(x, id_eqeq_p, 1, INT2FIX(-1)); +} + inline static VALUE f_kind_of_p(VALUE x, VALUE c) { @@ -916,6 +936,16 @@ nurat_fdiv(VALUE self, VALUE other) return f_to_f(f_div(self, other)); } +inline static VALUE +f_odd_p(VALUE integer) +{ + if (rb_funcall(integer, '%', 1, INT2FIX(2)) != INT2FIX(0)) { + return Qtrue; + } + return Qfalse; + +} + /* * call-seq: * rat ** numeric -> numeric @@ -942,6 +972,22 @@ nurat_expt(VALUE self, VALUE other) other = dat->num; /* c14n */ } + /* Deal with special cases of 0**n and 1**n */ + if (k_numeric_p(other) && k_exact_p(other)) { + get_dat1(self); + if (f_one_p(dat->den)) + if (f_one_p(dat->num)) + return f_rational_new_bang1(CLASS_OF(self), ONE); + else if (f_minus_one_p(dat->num) && k_integer_p(other)) + return f_rational_new_bang1(CLASS_OF(self), INT2FIX(f_odd_p(other) ? -1 : 1)); + else if (f_zero_p(dat->num)) + if (FIX2INT(f_cmp(other, ZERO)) == -1) + rb_raise_zerodiv(); + else + return f_rational_new_bang1(CLASS_OF(self), ZERO); + } + + /* General case */ switch (TYPE(other)) { case T_FIXNUM: { diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb index 208099a4ab..0496c0afe3 100644 --- a/test/ruby/test_rational.rb +++ b/test/ruby/test_rational.rb @@ -1143,6 +1143,26 @@ class Rational_Test < Test::Unit::TestCase assert_equal(1.0, Rational(n + 2, n + 1).to_f, '[ruby-dev:33852]') end + def test_power_of_1_and_minus_1 + bug5715 = '[ruby-core:41498]' + big = 1 << 66 + one = Rational( 1, 1) + assert_eql one, one ** -big , bug5715 + assert_eql one, (-one) ** -big , bug5715 + assert_eql -one, (-one) ** -(big+1) , bug5715 + assert_equal Complex, ((-one) ** Rational(1,3)).class + end + + def test_power_of_0 + bug5713 = '[ruby-core:41494]' + big = 1 << 66 + zero = Rational(0, 1) + assert_eql zero, zero ** big + assert_eql zero, zero ** Rational(2, 3) + assert_raise(ZeroDivisionError, bug5713) { Rational(0, 1) ** -big } + assert_raise(ZeroDivisionError, bug5713) { Rational(0, 1) ** Rational(-2,3) } + end + def test_known_bug end