Inside the for loop, the loop increment can be done within an unchecked block. As its unlikely we will reach the limit of uint256 for the loop index. Like below:
for (uint256 i; i < i_max; ) {
//some operation
unchecked {
i++;
}
}
Also there is no need to initialize i to 0 as its initialized to 0 by default.
The length of array used in for loops should be cached to save gas. For example: pooledTokens.length, amounts.length, balances.length etc in the following references:
Instead of require statement we can use custom error messages. Also require statements with an && can be split into two statements.
For example:
require(a > 0 && a < MAX_A, "a must be > 0 and < MAX_A");
a. for (uint256 i; i < numFacets; i++) b. for (uint8 i = 0; i < _pooledTokens.length; i++) (the i here cannot be more than 32(see line 408). So we can uncheck the i++ even though I is uint8) c. for (uint256 i = 0; i < tokenAddresses.length; i++) d. for (uint256 i = 0; i < calls.length; i++) e. for (uint8 i = 0; i < _pooledTokens.length; i++) f. for (uint8 i = 0; i < 10; i += 1) g. for (uint256 i = 0; i < xp.length; i++) h. for (uint256 i = 0; i < numTokens; i++) i. for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) j. for (uint256 i = 0; i < numTokens; i++) k. for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) l. for (uint256 j = 0; j < numTokens; j++) m. for (uint256 i = 0; i < numTokens; i++) n. for (uint256 i = 0; i < numTokens; i++) o. for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) p. for (uint256 i = 0; i < balances.length; i++) q. for (uint256 i = 0; i < balances.length; i++) r. for (uint256 i = 0; i < pooledTokens.length; i++) s. for (uint256 i = 0; i < pooledTokens.length; i++) t. for (uint256 i = 0; i < amounts.length; i++) u. for (uint256 i = 0; i < pooledTokens.length; i++) v. for (uint256 i = 0; i < pooledTokens.length; i++) w. for (uint256 i = 0; i < pooledTokens.length; i++) x. for (uint256 i = 0; i < pooledTokens.length; i++)
a1-a0 or a0-a1(line 64) will never overflow. Similarly t1-t0 will never overflow. So the equation can be simplified to: unchecked{ return a0 + (a1-a0) * (block.timestamp-t0) / (t1-t0); } b. https://github.com/code-423n4/2022-06-connext/blob/main/contracts/contracts/core/connext/libraries/AmplificationUtils.sol#L84-L85
can be rewritten as:
if(a == 0) a_must_be_gt0(); if(a >= MAX_A) a_must_notbe_gtMAX();
References below: a. require(block.timestamp >= self.initialATime.add(1 days), "Wait 1 day before starting ramp"); require(futureTime_ >= block.timestamp.add(MIN_RAMP_TIME), "Insufficient ramp time"); b. require(futureAPrecise.mul(MAX_ACHANGE) >= initialAPrecise, "futureA is too small"); c. require(futureAPrecise <= initialAPrecise.mul(MAX_ACHANGE), "futureA is too large"); d. require(self.futureATime > block.timestamp, "Ramp is already stopped"); e. require(isValidAction(_action), "!action"); f. require(msg.sender == diamondStorage().contractOwner, "LibDiamond: Must be contract owner"); g. require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut"); h. require(_facetAddress != address(0), "LibDiamondCut: Add facet can't be address(0)"); i. require(oldFacetAddress == address(0), "LibDiamondCut: Can't add function that already exists"); j. require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut"); k. require(_facetAddress != address(0), "LibDiamondCut: Add facet can't be address(0)"); l. require(oldFacetAddress != _facetAddress, "LibDiamondCut: Can't replace function with same function"); m. require(_functionSelectors.length > 0, "LibDiamondCut: No selectors in facet to cut"); n. require(_facetAddress == address(0), "LibDiamondCut: Remove facet address must be address(0)"); o. require(_facetAddress != address(0), "LibDiamondCut: Can't remove function that doesn't exist"); p. require(_facetAddress != address(this), "LibDiamondCut: Can't remove immutable function"); q. require(_calldata.length == 0, "LibDiamondCut: _init is address(0) but_calldata is not empty"); r. require(_calldata.length > 0, "LibDiamondCut: _calldata is empty but _init is not address(0)"); s. require(tokenIndex < xp.length, "Token index out of range"); t. require(tokenAmount <= xp[tokenIndex], "Withdraw exceeds available"); u. require(tokenIndex < numTokens, "Token not found"); v. require(numTokens == precisionMultipliers.length, "Balances must match multipliers"); w. require(tokenIndexFrom != tokenIndexTo, "Can't compare token to itself"); require(tokenIndexFrom < numTokens && tokenIndexTo < numTokens, "Tokens must be in pool"); x. require(tokenIndexFrom < xp.length && tokenIndexTo < xp.length, "Token index out of range"); y. require(tokenIndexFrom < xp.length && tokenIndexTo < xp.length, "Token index out of range"); z. require(amount <= totalSupply, "Cannot exceed total supply"); aa. require(index < self.pooledTokens.length, "Token index out of range"); bb. require(dx <= tokenFrom.balanceOf(msg.sender), "Cannot swap more than you own"); cc. require(dy >= minDy, "Swap didn't result in min tokens"); dd. require(dy <= self.balances[tokenIndexTo], "Cannot get more than pool balance"); ee. require(dx <= maxDx, "Swap needs more than max tokens"); ff. require(dx <= tokenFrom.balanceOf(msg.sender), "Cannot swap more than you own"); gg. require(dx == tokenFrom.balanceOf(address(this)).sub(beforeBalance), "not support fee token"); hh. require(dx <= tokenFrom.balanceOf(msg.sender), "Cannot swap more than you own"); ii. require(dy >= minDy, "Swap didn't result in min tokens"); jj. require(dy <= self.balances[tokenIndexTo], "Cannot get more than pool balance"); kk. require(dx <= maxDx, "Swap didn't result in min tokens"); ll. require(amounts.length == pooledTokens.length, "Amounts must match pooled tokens"); mm. require(v.totalSupply != 0 || amounts[i] > 0, "Must supply all tokens in pool"); nn. require(v.d1 > v.d0, "D should increase"); oo. require(toMint >= minToMint, "Couldn't mint min requested"); pp. require(amount <= lpToken.balanceOf(msg.sender), ">LP.balanceOf"); require(minAmounts.length == pooledTokens.length, "minAmounts must match poolTokens"); qq. require(amounts[i] >= minAmounts[i], "amounts[i] < minAmounts[i]"); rr. require(tokenAmount <= lpToken.balanceOf(msg.sender), ">LP.balanceOf"); require(tokenIndex < pooledTokens.length, "Token not found"); ss. require(dy >= minAmount, "dy < minAmount"); tt. require(amounts.length == pooledTokens.length, "Amounts should match pool tokens"); uu. require(maxBurnAmount <= v.lpToken.balanceOf(msg.sender) && maxBurnAmount != 0, ">LP.balanceOf"); vv. require(tokenAmount != 0, "Burnt amount cannot be zero"); ww. require(tokenAmount <= maxBurnAmount, "tokenAmount > maxBurnAmount"); xx. require(newAdminFee <= MAX_ADMIN_FEE, "Fee is too high"); yy. require(newSwapFee <= MAX_SWAP_FEE, "Fee is too high"); zz. require(_remote != bytes32(0), "!remote"); aaa. require(msg.sender == connext, "#OC:027"); bbb. require(msg.sender == admin, "caller is not the admin"); ccc. require(baseTokenPrice > 0, "invalid base token"); ddd. require(amount != 0, "LPToken: cannot mint 0"); eee. require(to != address(this), "LPToken: cannot send to itself"); fff. require(_tokenId.domain != 0, "!repr"); ggg. require(_token != address(0), "!token"); hhh. require(_pooledTokens.length > 1, "_pooledTokens.length <= 1"); require(_pooledTokens.length <= 32, "_pooledTokens.length > 32"); require(_pooledTokens.length == decimals.length, "_pooledTokens decimals mismatch"); iii. require(address(_pooledTokens[i]) != address(0), "The 0 address isn't an ERC-20"); require(decimals[i] <= SwapUtils.POOL_PRECISION_DECIMALS, "Token decimals exceeds max"); jjj. require(_a < AmplificationUtils.MAX_A, "_a exceeds maximum"); require(_fee < SwapUtils.MAX_SWAP_FEE, "_fee exceeds maximum"); require(_adminFee < SwapUtils.MAX_ADMIN_FEE, "_adminFee exceeds maximum"); kkk. require(lpToken.initialize(lpTokenName, lpTokenSymbol), "could not init lpToken clone"); lll. require(block.timestamp <= deadline, "Deadline not met"); mmm. require(index < swapStorage.pooledTokens.length, "Out of range"); nnn. require(address(getToken(index)) == tokenAddress, "Token does not exist"); ooo. require(index < swapStorage.pooledTokens.length, "Index out of range");