diff --git a/vendor/gopkg.in/inf.v0/rounder.go b/vendor/gopkg.in/inf.v0/rounder.go
new file mode 100644
index 0000000..3a97ef5
--- /dev/null
+++ b/vendor/gopkg.in/inf.v0/rounder.go
@@ -0,0 +1,145 @@
+package inf
+
+import (
+	"math/big"
+)
+
+// Rounder represents a method for rounding the (possibly infinite decimal)
+// result of a division to a finite Dec. It is used by Dec.Round() and
+// Dec.Quo().
+//
+// See the Example for results of using each Rounder with some sample values.
+//
+type Rounder rounder
+
+// See http://speleotrove.com/decimal/damodel.html#refround for more detailed
+// definitions of these rounding modes.
+var (
+	RoundDown     Rounder // towards 0
+	RoundUp       Rounder // away from 0
+	RoundFloor    Rounder // towards -infinity
+	RoundCeil     Rounder // towards +infinity
+	RoundHalfDown Rounder // to nearest; towards 0 if same distance
+	RoundHalfUp   Rounder // to nearest; away from 0 if same distance
+	RoundHalfEven Rounder // to nearest; even last digit if same distance
+)
+
+// RoundExact is to be used in the case when rounding is not necessary.
+// When used with Quo or Round, it returns the result verbatim when it can be
+// expressed exactly with the given precision, and it returns nil otherwise.
+// QuoExact is a shorthand for using Quo with RoundExact.
+var RoundExact Rounder
+
+type rounder interface {
+
+	// When UseRemainder() returns true, the Round() method is passed the
+	// remainder of the division, expressed as the numerator and denominator of
+	// a rational.
+	UseRemainder() bool
+
+	// Round sets the rounded value of a quotient to z, and returns z.
+	// quo is rounded down (truncated towards zero) to the scale obtained from
+	// the Scaler in Quo().
+	//
+	// When the remainder is not used, remNum and remDen are nil.
+	// When used, the remainder is normalized between -1 and 1; that is:
+	//
+	//  -|remDen| < remNum < |remDen|
+	//
+	// remDen has the same sign as y, and remNum is zero or has the same sign
+	// as x.
+	Round(z, quo *Dec, remNum, remDen *big.Int) *Dec
+}
+
+type rndr struct {
+	useRem bool
+	round  func(z, quo *Dec, remNum, remDen *big.Int) *Dec
+}
+
+func (r rndr) UseRemainder() bool {
+	return r.useRem
+}
+
+func (r rndr) Round(z, quo *Dec, remNum, remDen *big.Int) *Dec {
+	return r.round(z, quo, remNum, remDen)
+}
+
+var intSign = []*big.Int{big.NewInt(-1), big.NewInt(0), big.NewInt(1)}
+
+func roundHalf(f func(c int, odd uint) (roundUp bool)) func(z, q *Dec, rA, rB *big.Int) *Dec {
+	return func(z, q *Dec, rA, rB *big.Int) *Dec {
+		z.Set(q)
+		brA, brB := rA.BitLen(), rB.BitLen()
+		if brA < brB-1 {
+			// brA < brB-1 => |rA| < |rB/2|
+			return z
+		}
+		roundUp := false
+		srA, srB := rA.Sign(), rB.Sign()
+		s := srA * srB
+		if brA == brB-1 {
+			rA2 := new(big.Int).Lsh(rA, 1)
+			if s < 0 {
+				rA2.Neg(rA2)
+			}
+			roundUp = f(rA2.Cmp(rB)*srB, z.UnscaledBig().Bit(0))
+		} else {
+			// brA > brB-1 => |rA| > |rB/2|
+			roundUp = true
+		}
+		if roundUp {
+			z.UnscaledBig().Add(z.UnscaledBig(), intSign[s+1])
+		}
+		return z
+	}
+}
+
+func init() {
+	RoundExact = rndr{true,
+		func(z, q *Dec, rA, rB *big.Int) *Dec {
+			if rA.Sign() != 0 {
+				return nil
+			}
+			return z.Set(q)
+		}}
+	RoundDown = rndr{false,
+		func(z, q *Dec, rA, rB *big.Int) *Dec {
+			return z.Set(q)
+		}}
+	RoundUp = rndr{true,
+		func(z, q *Dec, rA, rB *big.Int) *Dec {
+			z.Set(q)
+			if rA.Sign() != 0 {
+				z.UnscaledBig().Add(z.UnscaledBig(), intSign[rA.Sign()*rB.Sign()+1])
+			}
+			return z
+		}}
+	RoundFloor = rndr{true,
+		func(z, q *Dec, rA, rB *big.Int) *Dec {
+			z.Set(q)
+			if rA.Sign()*rB.Sign() < 0 {
+				z.UnscaledBig().Add(z.UnscaledBig(), intSign[0])
+			}
+			return z
+		}}
+	RoundCeil = rndr{true,
+		func(z, q *Dec, rA, rB *big.Int) *Dec {
+			z.Set(q)
+			if rA.Sign()*rB.Sign() > 0 {
+				z.UnscaledBig().Add(z.UnscaledBig(), intSign[2])
+			}
+			return z
+		}}
+	RoundHalfDown = rndr{true, roundHalf(
+		func(c int, odd uint) bool {
+			return c > 0
+		})}
+	RoundHalfUp = rndr{true, roundHalf(
+		func(c int, odd uint) bool {
+			return c >= 0
+		})}
+	RoundHalfEven = rndr{true, roundHalf(
+		func(c int, odd uint) bool {
+			return c > 0 || c == 0 && odd == 1
+		})}
+}