From d428317f91f0686f50f6fd45db668418a57087f3 Mon Sep 17 00:00:00 2001
From: rigelrozanski <rigel.rozanski@gmail.com>
Date: Sat, 22 Sep 2018 13:56:48 -0400
Subject: [PATCH] import decimal from fee-distr PR

---
 types/decimal.go      | 26 ++++++++++++++++++++++++++
 types/decimal_test.go | 26 ++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/types/decimal.go b/types/decimal.go
index 8e7db1340..d6c93f617 100644
--- a/types/decimal.go
+++ b/types/decimal.go
@@ -323,6 +323,32 @@ func (d Dec) RoundInt() Int {
 
 //___________________________________________________________________________________
 
+// similar to chopPrecisionAndRound, but always rounds down
+func chopPrecisionAndTruncate(d *big.Int) *big.Int {
+	return d.Quo(d, precisionReuse)
+}
+
+func chopPrecisionAndTruncateNonMutative(d *big.Int) *big.Int {
+	tmp := new(big.Int).Set(d)
+	return chopPrecisionAndTruncate(tmp)
+}
+
+// RoundInt64 rounds the decimal using bankers rounding
+func (d Dec) TruncateInt64() int64 {
+	chopped := chopPrecisionAndTruncateNonMutative(d.Int)
+	if !chopped.IsInt64() {
+		panic("Int64() out of bound")
+	}
+	return chopped.Int64()
+}
+
+// RoundInt round the decimal using bankers rounding
+func (d Dec) TruncateInt() Int {
+	return NewIntFromBigInt(chopPrecisionAndTruncateNonMutative(d.Int))
+}
+
+//___________________________________________________________________________________
+
 // reuse nil values
 var (
 	nilAmino string
diff --git a/types/decimal_test.go b/types/decimal_test.go
index 779460c25..161215467 100644
--- a/types/decimal_test.go
+++ b/types/decimal_test.go
@@ -202,6 +202,32 @@ func TestBankerRoundChop(t *testing.T) {
 	}
 }
 
+func TestTruncate(t *testing.T) {
+	tests := []struct {
+		d1  Dec
+		exp int64
+	}{
+		{mustNewDecFromStr(t, "0"), 0},
+		{mustNewDecFromStr(t, "0.25"), 0},
+		{mustNewDecFromStr(t, "0.75"), 0},
+		{mustNewDecFromStr(t, "1"), 1},
+		{mustNewDecFromStr(t, "1.5"), 1},
+		{mustNewDecFromStr(t, "7.5"), 7},
+		{mustNewDecFromStr(t, "7.6"), 7},
+		{mustNewDecFromStr(t, "7.4"), 7},
+		{mustNewDecFromStr(t, "100.1"), 100},
+		{mustNewDecFromStr(t, "1000.1"), 1000},
+	}
+
+	for tcIndex, tc := range tests {
+		resNeg := tc.d1.Neg().TruncateInt64()
+		require.Equal(t, -1*tc.exp, resNeg, "negative tc %d", tcIndex)
+
+		resPos := tc.d1.TruncateInt64()
+		require.Equal(t, tc.exp, resPos, "positive tc %d", tcIndex)
+	}
+}
+
 func TestToLeftPadded(t *testing.T) {
 	tests := []struct {
 		dec    Dec