From 2323ccb6eb054ea0378c2e37071b0521da73d409 Mon Sep 17 00:00:00 2001
From: mingda <leimingda@pku.edu.cn>
Date: Mon, 30 Nov 2020 11:59:55 +0800
Subject: [PATCH] support k = 0 case

---
 contracts/lib/DODOMath.sol | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/contracts/lib/DODOMath.sol b/contracts/lib/DODOMath.sol
index 34c5fab..408e92b 100644
--- a/contracts/lib/DODOMath.sol
+++ b/contracts/lib/DODOMath.sol
@@ -29,6 +29,8 @@ library DODOMath {
 
         i is the price of res-V trading pair
 
+        support k=1 & k=0 case
+
         [round down]
     */
     function _GeneralIntegrate(
@@ -53,6 +55,8 @@ library DODOMath {
         i is the price of delta-V trading pair
         give out target of V
 
+        support k=1 & k=0 case
+
         [round down]
     */
     function _SolveQuadraticFunctionForTarget(
@@ -60,7 +64,10 @@ library DODOMath {
         uint256 delta,
         uint256 i,
         uint256 k
-    ) internal pure returns (uint256 V0) {
+    ) internal pure returns (uint256) {
+        if (k == 0) {
+            return V1.add(DecimalMath.mulFloor(i, delta));
+        }
         // V0 = V1*(1+(sqrt-1)/2k)
         // sqrt = √(1+4kidelta/V1)
         // premium = 1+(sqrt-1)/2k
@@ -93,6 +100,8 @@ library DODOMath {
 
         i is the price of delta-V trading pair
 
+        support k=1 & k=0 case
+
         [round down]
     */
     function _SolveQuadraticFunctionForTrade(
@@ -107,6 +116,10 @@ library DODOMath {
             return 0;
         }
 
+        if (k == 0) {
+            return DecimalMath.mulFloor(i, delta);
+        }
+
         if (k == DecimalMath.ONE) {
             // if k==1
             // Q2=Q1/(1+ideltaBQ1/Q0/Q0)