1 files changed, 74 insertions, 0 deletions
diff --git a/ext/bigdecimal/lib/bigdecimal/util.rb b/ext/bigdecimal/lib/bigdecimal/util.rb
new file mode 100644
index 0000000000..d9b7ae3131
--- /dev/null
+++ b/ext/bigdecimal/lib/bigdecimal/util.rb
@@ -0,0 +1,74 @@
+#
+# BigDecimal utility library.
+# ----------------------------------------------------------------------
+# Contents:
+#
+#   String#
+#     to_d      ... to BigDecimal
+#
+#   Float#
+#     to_d      ... to BigDecimal
+#
+#   BigDecimal#
+#     to_digits ... to xxxxx.yyyy form digit string(not 0.zzzE?? form).
+#     to_r      ... to Rational
+#
+#   Rational#
+#     to_d      ... to BigDecimal
+#
+# ----------------------------------------------------------------------
+#
+class Float < Numeric
+  def to_d
+    BigFloat::new(selt.to_s)
+  end
+end
+
+class String
+  def to_d
+    BigDecimal::new(self)
+  end
+end
+
+class BigDecimal < Numeric
+  # to "nnnnnn.mmm" form digit string
+  def to_digits
+     if self.nan? || self.infinite?
+        self.to_s
+     else
+       s,i,y,z = self.fix.split
+       s,f,y,z = self.frac.split
+       if s > 0
+         s = ""
+       else
+         s = "-"
+       end
+       s + i + "." + f
+     end
+  end
+
+  # Convert BigDecimal to Rational
+  def to_r 
+     sign,digits,base,power = self.split
+     numerator = sign*digits.to_i
+     denomi_power = power - digits.size # base is always 10
+     if denomi_power < 0
+        denominator = base ** (-denomi_power)
+     else
+        denominator = base ** denomi_power
+     end
+     Rational(numerator,denominator)
+  end
+end
+
+class Rational < Numeric
+  # Convert Rational to BigDecimal
+  # to_d returns an array [quotient,residue]
+  def to_d(nFig=0)
+     num = self.numerator.to_s
+     if nFig<=0
+        nFig = BigDecimal.double_fig*2+1
+     end
+     BigDecimal.new(num).div(self.denominator,nFig)
+  end
+end