Slightly more efficient hashmap remove

zyedidia · Apr 13, 2022 · b42c923 · b42c923
1 parent 7383fd2
commit b42c923
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/hashmap/map.go b/hashmap/map.go
@@ -139,7 +139,7 @@ func (m *Map[K, V]) Remove(key K) {
 	idx := hash & (m.capacity - 1)
 
 	for m.entries[idx].filled && !m.ops.equals(m.entries[idx].key, key) {
-		idx = (idx + 1) % m.capacity
+		idx = (idx + 1) & (m.capacity - 1)
 	}
 
 	if !m.entries[idx].filled {
@@ -148,13 +148,13 @@ func (m *Map[K, V]) Remove(key K) {
 
 	m.remove(idx)
 
-	idx = (idx + 1) % m.capacity
+	idx = (idx + 1) & (m.capacity - 1)
 	for m.entries[idx].filled {
 		krehash := m.entries[idx].key
 		vrehash := m.entries[idx].value
 		m.remove(idx)
 		m.Put(krehash, vrehash)
-		idx = (idx + 1) % m.capacity
+		idx = (idx + 1) & (m.capacity - 1)
 	}
 
 	// halves the array if it is 12.5% full or less

diff --git a/hashmap/map_test.go b/hashmap/map_test.go
@@ -21,7 +21,7 @@ func checkeq[K any, V comparable](cm *hashmap.Map[K, V], get func(k K) (V, bool)
 
 func TestCrossCheck(t *testing.T) {
 	stdm := make(map[uint64]uint32)
-	cowm := hashmap.New[uint64, uint32](1, g.Equals[uint64], g.HashUint64)
+	cowm := hashmap.New[uint64, uint32](uint64(rand.Intn(1024)), g.Equals[uint64], g.HashUint64)
 
 	const nops = 1000