From 9f3042be407cf307fbf6c3318f02f94ae27e6292 Mon Sep 17 00:00:00 2001
From: Poseidon <shenao.78@163.com>
Date: Wed, 22 Jan 2020 15:05:54 +0800
Subject: [PATCH] fix decimal (#479)

* fix decimal

* fix decimal

* bug fix

* fix decimal
---
 application/mov/match/match.go      |  15 +---
 application/mov/match/match_test.go | 160 ++++++++++++++++++++++++++++++++++++
 2 files changed, 164 insertions(+), 11 deletions(-)

diff --git a/application/mov/match/match.go b/application/mov/match/match.go
index 4c0234f9..845c2283 100644
--- a/application/mov/match/match.go
+++ b/application/mov/match/match.go
@@ -240,20 +240,13 @@ func IsMatched(orders []*common.Order) bool {
 		return false
 	}
 
-	rate := orderRatio(sortedOrders[0])
-	oppositeRate := big.NewFloat(0).SetInt64(1)
+	rate := big.NewRat(sortedOrders[0].RatioDenominator, sortedOrders[0].RatioNumerator)
+	oppositeRate := big.NewRat(1, 1)
 	for i := 1; i < len(sortedOrders); i++ {
-		oppositeRate.Mul(oppositeRate, orderRatio(sortedOrders[i]))
+		oppositeRate.Mul(oppositeRate, big.NewRat(sortedOrders[i].RatioNumerator, sortedOrders[i].RatioDenominator))
 	}
 
-	one := big.NewFloat(0).SetInt64(1)
-	return one.Quo(one, rate).Cmp(oppositeRate) >= 0
-}
-
-func orderRatio(order *common.Order) *big.Float {
-	ratio := big.NewFloat(0).SetInt64(order.RatioNumerator)
-	ratio.Quo(ratio, big.NewFloat(0).SetInt64(order.RatioDenominator))
-	return ratio
+	return rate.Cmp(oppositeRate) >= 0
 }
 
 func setMatchTxArguments(txInput *types.TxInput, isPartialTrade bool, position int, receiveAmounts uint64) {
diff --git a/application/mov/match/match_test.go b/application/mov/match/match_test.go
index 640f4cfb..7d013ec8 100644
--- a/application/mov/match/match_test.go
+++ b/application/mov/match/match_test.go
@@ -256,3 +256,163 @@ func TestValidateTradePairs(t *testing.T) {
 		}
 	}
 }
+
+func TestIsMatched(t *testing.T) {
+	cases := []struct {
+		desc        string
+		orders      []*common.Order
+		wantMatched bool
+	}{
+		{
+			desc: "ratio is equals",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   6250,
+					RatioDenominator: 3,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   3,
+					RatioDenominator: 6250,
+				},
+			},
+			wantMatched: true,
+		},
+		{
+			desc: "ratio is equals, and numerator and denominator are multiples of the opposite",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   6250,
+					RatioDenominator: 3,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   9,
+					RatioDenominator: 18750,
+				},
+			},
+			wantMatched: true,
+		},
+		{
+			desc: "matched with a slight diff",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   62500000000000000,
+					RatioDenominator: 30000000000001,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   3,
+					RatioDenominator: 6250,
+				},
+			},
+			wantMatched: true,
+		},
+		{
+			desc: "not matched with a slight diff",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   62500000000000001,
+					RatioDenominator: 30000000000000,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   3,
+					RatioDenominator: 6250,
+				},
+			},
+			wantMatched: false,
+		},
+		{
+			desc: "ring matched",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   2000000003,
+					RatioDenominator: 100000001,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.EOS,
+					RatioNumerator:   400000000001,
+					RatioDenominator: 2000000003,
+				},
+				{
+					FromAssetID:      &mock.EOS,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   100000001,
+					RatioDenominator: 400000000001,
+				},
+			},
+			wantMatched: true,
+		},
+		{
+			desc: "ring matched with a slight diff",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   2000000003,
+					RatioDenominator: 100000001,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.EOS,
+					RatioNumerator:   400000000001,
+					RatioDenominator: 2000000003,
+				},
+				{
+					FromAssetID:      &mock.EOS,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   100000000,
+					RatioDenominator: 400000000001,
+				},
+			},
+			wantMatched: true,
+		},
+		{
+			desc: "ring fail matched with a slight diff",
+			orders: []*common.Order{
+				{
+					FromAssetID:      &mock.BTC,
+					ToAssetID:        &mock.ETH,
+					RatioNumerator:   2000000003,
+					RatioDenominator: 100000001,
+				},
+				{
+					FromAssetID:      &mock.ETH,
+					ToAssetID:        &mock.EOS,
+					RatioNumerator:   400000000001,
+					RatioDenominator: 2000000003,
+				},
+				{
+					FromAssetID:      &mock.EOS,
+					ToAssetID:        &mock.BTC,
+					RatioNumerator:   100000002,
+					RatioDenominator: 400000000001,
+				},
+			},
+			wantMatched: false,
+		},
+	}
+
+	for i, c := range cases {
+		gotMatched := IsMatched(c.orders)
+		if gotMatched != c.wantMatched {
+			t.Errorf("#%d(%s) got matched:%v, want matched:%v", i, c.desc, gotMatched, c.wantMatched)
+		}
+	}
+}
-- 
2.11.0