avoid needlessly creating an array

vigna · Dec 23, 2024 · 6f24bb2 · 6f24bb2
1 parent 2096752
commit 6f24bb2
Showing 1 changed file with 17 additions and 13 deletions.
diff --git a/drv/Map.drv b/drv/Map.drv
@@ -835,28 +835,32 @@ public interface MAP KEY_VALUE_GENERIC extends FUNCTION KEY_VALUE_GENERIC, Map<K
 		if (entries.length == 0) return MAPS.EMPTY_MAP;
 		if (entries.length == 1) return MAPS.singleton(entries[0].ENTRY_GET_KEY(), entries[0].ENTRY_GET_VALUE());
 
-		KEY_GENERIC_TYPE[] keys = KEY_GENERIC_ARRAY_CAST new KEY_TYPE[entries.length];
-		VALUE_GENERIC_TYPE[] vals = VALUE_GENERIC_ARRAY_CAST new VALUE_TYPE[entries.length];
-
-		for (int i = 0; i < entries.length; ++i) {
-			MAP.Entry KEY_VALUE_GENERIC entry = entries[i];
-			keys[i] = entry.ENTRY_GET_KEY();
-			// Prevent duplicate keys
-			for (int j = 0; j < i; ++j) if (KEY_EQUALS(keys[j], keys[i])) throw new IllegalArgumentException("duplicate key: " + keys[i]);
-			vals[i] = entry.ENTRY_GET_VALUE();
-		}
 		if (entries.length <= 8) {
+			KEY_GENERIC_TYPE[] keys = KEY_GENERIC_ARRAY_CAST new KEY_TYPE[entries.length];
+			VALUE_GENERIC_TYPE[] vals = VALUE_GENERIC_ARRAY_CAST new VALUE_TYPE[entries.length];
+
+			for (int i = 0; i < entries.length; ++i) {
+				MAP.Entry KEY_VALUE_GENERIC entry = entries[i];
+				keys[i] = entry.ENTRY_GET_KEY();
+				// Prevent duplicate keys
+				for (int j = 0; j < i; ++j) if (KEY_EQUALS(keys[j], keys[i])) throw new IllegalArgumentException("duplicate key: " + keys[i]);
+				vals[i] = entry.ENTRY_GET_VALUE();
+			}
 			return MAPS.unmodifiable(new ARRAY_MAP KEY_VALUE_GENERIC_DIAMOND(keys, vals, entries.length));
 		} else {
-			return MAPS.unmodifiable(new OPEN_HASH_MAP KEY_VALUE_GENERIC_DIAMOND(keys, vals, 0.75f));
+			MAP KEY_VALUE_GENERIC newMap = new OPEN_HASH_MAP KEY_VALUE_GENERIC_DIAMOND(entries.length, 0.75f);
+			for (MAP.Entry KEY_VALUE_GENERIC entry : entries) {
+				if (!VALUE_IS_NULL(newMap.put(entry.ENTRY_GET_KEY(), entry.ENTRY_GET_VALUE()))) throw new IllegalArgumentException("duplicate key: " + entry.ENTRY_GET_KEY());
+			}
+			return MAPS.unmodifiable(newMap);
 		}
 	}
 
 	/** Returns an unmodifiable, type-specific entry.
 	 * See {@link java.util.Map#entry(Object, Object)} */
 	static KEY_VALUE_GENERIC Entry KEY_VALUE_GENERIC entry(KEY_GENERIC_TYPE key, VALUE_GENERIC_TYPE value) {
-    	return new ABSTRACT_MAP.BasicEntry KEY_VALUE_GENERIC_DIAMOND(key, value);
-    }
+		return new ABSTRACT_MAP.BasicEntry KEY_VALUE_GENERIC_DIAMOND(key, value);
+	}
 
 	/** A type-specific {@link java.util.Map.Entry}; provides some additional methods
 	 *  that use polymorphism to avoid (un)boxing.