caching array length

[code423n4]

Handle

pants

Vulnerability details

Vulnerability details

There are many for loops that follows this for-each pattern:
(for example line 227 in FeeSplitter.sol or line 32 in MixinOperatorResolver.sol)

for (uint256 i = 0; i < array.length; i++) {
// do something with array[i]
}

In such for loops, the `array.length` is read on every iteration, instead of caching it once in a local variable and read it again using the local variable.

## Impact
Storage reads are much more expensive than reading local variables. Memory and calldata reads are a bit more expensive than reading local variables.

## Tool Used
Manual code review.

## Recommended Mitigation Steps
Read these values from storage / memory / calldata once, cache them in local variables and then read them again using the local variables. For example:

uint256 length = array.length;
for (uint256 i = 0; i < length; i++) {
// do something with array[i]
}

[adrien-supizet]

duplicate #7