dodomath fix && proxy test

contracts/lib/DODOMath.sol

@@ -74,8 +74,16 @@ library DODOMath {
         // V0 = V1*(1+(sqrt-1)/2k)
         // sqrt = √(1+4kidelta/V1)
         // premium = 1+(sqrt-1)/2k
-        // uint256 sqrt = DecimalMath.multiMulWithDiv((4 * k).mul(i),delta,V1).add(DecimalMath.ONE2).sqrt();
-        uint256 sqrt = (4 * k).mul(i).mul(delta).div(V1).add(DecimalMath.ONE2).sqrt();
+        // uint256 sqrt = (4 * k).mul(i).mul(delta).div(V1).add(DecimalMath.ONE2).sqrt();
+        uint256 sqrt;
+        uint256 ki = (4 * k).mul(i);
+        if(ki == 0 ) {
+            sqrt = DecimalMath.ONE;
+        }else if(ki * delta / ki == delta) {
+            sqrt = (ki * delta).div(V1).add(DecimalMath.ONE2).sqrt();
+        }else {
+            sqrt = (4 * k).mul(i).div(V1).mul(delta).add(DecimalMath.ONE2).sqrt();
+        }
         uint256 premium = DecimalMath.divFloor(sqrt.sub(DecimalMath.ONE), k * 2).add(
             DecimalMath.ONE
         );
@@ -129,8 +137,16 @@ library DODOMath {
             // Q2=Q1/(1+ideltaBQ1/Q0/Q0)
             // temp = ideltaBQ1/Q0/Q0
             // Q1-Q2 = Q1*(temp/(1+temp))
-            // uint256 temp = DecimalMath.multiMulWithDiv(i.mul(delta),V1,V0).div(V0);
-            uint256 temp = i.mul(delta).mul(V1).div(V0.mul(V0));
+            // uint256 temp = i.mul(delta).mul(V1).div(V0.mul(V0));
+            uint256 temp;
+            uint256 idelta = i.mul(delta);
+            if(idelta == 0) {
+                temp = 0;
+            }else if(idelta * V1 / idelta == V1) {
+                temp = (idelta * V1).div(V0.mul(V0));
+            }else {
+                temp = delta.mul(V1).div(V0).mul(i).div(V0); 
+            }
             return V1.mul(temp).div(temp.add(DecimalMath.ONE));
         }
 

contracts/lib/DecimalMath.sol

@@ -45,10 +45,4 @@ library DecimalMath {
     function reciprocalCeil(uint256 target) internal pure returns (uint256) {
         return uint256(10**36).divCeil(target);
     }
-
-    function multiMulWithDiv(uint256 x, uint256 y, uint256 z) internal pure returns (uint256) {
-        uint256 a = x.div(z); uint256 b = x.mod(z); // x = a * z + b
-        uint256 c = y.div(z); uint256 d = y.mod(z); // y = c * z + d
-        return a.mul(b).mul(z).add(a.mul(d)).add(b.mul(c)).add(b.mul(d).div(z));
-    }
 }

contracts/lib/SafeMath.sol

@@ -32,11 +32,6 @@ library SafeMath {
         return a / b;
     }
 
-    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
-        require(b > 0, "MOD_ERROR");
-        return a % b;
-    }
-
     function divCeil(uint256 a, uint256 b) internal pure returns (uint256) {
         uint256 quotient = div(a, b);
         uint256 remainder = a - quotient * b;