fix: prevent underflow

hodlmybeer · Jul 27, 2021 · 566c811 · 566c811
1 parent e905795
commit 566c811
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/contracts/core/HodlERC20.sol b/contracts/core/HodlERC20.sol
@@ -101,7 +101,7 @@ contract HodlERC20 is ERC20PermitUpgradeable {
     require(address(_token) != address(_bonusToken), "INVALID_BONUS_TOKEN");
     require(_feeRecipient != address(0), "INVALID_RECIPIENT");
 
-    totalTime = _expiry - block.timestamp;
+    totalTime = _expiry.sub(block.timestamp);
 
     token = IERC20WithDetail(_token);
     bonusToken = IERC20WithDetail(_bonusToken);
@@ -359,7 +359,7 @@ contract HodlERC20 is ERC20PermitUpgradeable {
    *                      (total duration)^ n
    */
   function _calculateShares(uint256 _amount) internal view returns (uint256) {
-    uint256 timeLeft = expiry - block.timestamp;
+    uint256 timeLeft = expiry.sub(block.timestamp);
     return _amount.mul(timeLeft**n).div(totalTime**n);
   }