WIP

cardano-foundation · Jul 27, 2021 · 3e3ce61 · 3e3ce61
1 parent a6b2303
commit 3e3ce61
Showing 1 changed file with 19 additions and 8 deletions.
diff --git a/lib/core/src/Cardano/Wallet/Primitive/CoinSelection/Collateral.hs b/lib/core/src/Cardano/Wallet/Primitive/CoinSelection/Collateral.hs
@@ -92,14 +92,24 @@ selectCollateral params
             [1 .. maximumCollateralEntryCount]
 
     smallestValidCombinationOfSize :: Int -> Maybe (Map inputId Coin)
-    smallestValidCombinationOfSize size = coinsAvailable
-        & Map.toList
-        & (`subsequencesOfSize` size)
-        & fmap (\ics -> (ics, F.foldMap snd ics))
-        & L.dropWhile ((< minimumCollateralAmount) . snd)
-        & L.sortOn snd
-        & listToMaybe
-        & fmap (Map.fromList . fst)
+    smallestValidCombinationOfSize size = guardSearchSpaceSize $
+        coinsAvailable
+            & Map.toList
+            & (`subsequencesOfSize` size)
+            & fmap (\ics -> (ics, F.foldMap snd ics))
+            & L.dropWhile ((< minimumCollateralAmount) . snd)
+            & L.sortOn snd
+            & listToMaybe
+            & fmap (Map.fromList . fst)
+      where
+        guardSearchSpaceSize :: Maybe a -> Maybe a
+        guardSearchSpaceSize =
+            case (requiredSearchSpaceSize, maximumSearchSpaceSize) of
+                (r, Just m) | r > m -> const Nothing
+                _ -> id
+          where
+            requiredSearchSpaceSize =
+                Map.size coinsAvailable `numberOfSubsequencesOfSize` size
 
     largestCombinationAvailable :: Map inputId Coin
     largestCombinationAvailable = coinsAvailable
@@ -112,6 +122,7 @@ selectCollateral params
         { coinsAvailable
         , minimumCollateralAmount
         , maximumCollateralEntryCount
+        , maximumSearchSpaceSize
         } = params
 
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