Add BigDecimal#precision_scale

Author: mrkn

ext/bigdecimal/bigdecimal.c

@@ -481,6 +481,24 @@ BigDecimal_scale(VALUE self)
     return SSIZET2NUM(scale);
 }
 
+/*
+ *  call-seq:
+ *    precision_scale -> [integer, integer]
+ *
+ *  Returns a 2-length array; the first item is the result of
+ *  BigDecimal#precision and the second one is of BigDecimal#scale.
+ *
+ *  See BigDecimal#precision.
+ *  See BigDecimal#scale.
+ */
+static VALUE
+BigDecimal_precision_scale(VALUE self)
+{
+    ssize_t precision, scale;
+    BigDecimal_count_precision_and_scale(self, &precision, &scale);
+    return rb_assoc_new(SSIZET2NUM(precision), SSIZET2NUM(scale));
+}
+
 /*
  *  call-seq:
  *    n_significant_digits -> integer
@@ -4228,6 +4246,7 @@ Init_bigdecimal(void)
     rb_define_method(rb_cBigDecimal, "precs", BigDecimal_prec, 0);
     rb_define_method(rb_cBigDecimal, "precision", BigDecimal_precision, 0);
     rb_define_method(rb_cBigDecimal, "scale", BigDecimal_scale, 0);
+    rb_define_method(rb_cBigDecimal, "precision_scale", BigDecimal_precision_scale, 0);
     rb_define_method(rb_cBigDecimal, "n_significant_digits", BigDecimal_n_significant_digits, 0);
 
     rb_define_method(rb_cBigDecimal, "add", BigDecimal_add2, 2);

test/bigdecimal/test_bigdecimal.rb

@@ -2123,6 +2123,17 @@ def test_scale_special
     end
   end
 
+  def test_precision_scale
+    assert_equal([2, 0], BigDecimal("11.0").precision_scale)
+    assert_equal([2, 1], BigDecimal("1.1").precision_scale)
+    assert_equal([2, 2], BigDecimal("0.11").precision_scale)
+
+    BigDecimal.save_exception_mode do
+      BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+      assert_equal([0, 0], BigDecimal("Infinity").precision_scale)
+    end
+  end
+
   def test_n_significant_digits_only_integer
     assert_equal(0, BigDecimal(0).n_significant_digits)
     assert_equal(1, BigDecimal(1).n_significant_digits)