Optimized mask creation in draw calc (#215)

* Optimized mask creation in draw calc * opt even further Co-authored-by: Aodhgan <aodhgan@pooltogether.com>
pooltogether · Oct 14, 2021 · 9d0ca8e · 9d0ca8e
1 parent 8483ce5
commit 9d0ca8e
Showing 1 changed file with 3 additions and 5 deletions.
diff --git a/contracts/DrawCalculator.sol b/contracts/DrawCalculator.sol
@@ -356,13 +356,11 @@ contract DrawCalculator is IDrawCalculator, Ownable {
         returns (uint256[] memory)
     {
         uint256[] memory masks = new uint256[](_prizeDistribution.matchCardinality);
-        uint256 _bitRangeMaskValue = (2**_prizeDistribution.bitRangeSize) - 1; // get a decimal representation of bitRangeSize
+        masks[0] =  (2**_prizeDistribution.bitRangeSize) - 1;
 
-        for (uint8 maskIndex = 0; maskIndex < _prizeDistribution.matchCardinality; maskIndex++) {
-            // create mask of width bitRangeSize bits at index
-            uint256 _matchIndexOffset = uint256(maskIndex) * uint256(_prizeDistribution.bitRangeSize);
+        for (uint8 maskIndex = 1; maskIndex < _prizeDistribution.matchCardinality; maskIndex++) {
             // shift mask bits to correct position and insert in result mask array
-            masks[maskIndex] = _bitRangeMaskValue << _matchIndexOffset;
+            masks[maskIndex] = masks[maskIndex - 1] << _prizeDistribution.bitRangeSize;
         }
 
         return masks;