Update #47 - Singleplayer lag fixes

sources/main/java/com/carrotsearch/hppc/Containers.java

@@ -0,0 +1,68 @@
+/*
+ * HPPC
+ *
+ * Copyright (C) 2010-2024 Carrot Search s.c. and contributors
+ * All rights reserved.
+ *
+ * Refer to the full license file "LICENSE.txt":
+ * https://github.com/carrotsearch/hppc/blob/master/LICENSE.txt
+ */
+package com.carrotsearch.hppc;
+
+import com.carrotsearch.hppc.internals.SuppressForbidden;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Constants used as defaults in containers.
+ *
+ * @see HashContainers
+ */
+public final class Containers {
+  /** The default number of expected elements for containers. */
+  public static final int DEFAULT_EXPECTED_ELEMENTS = 4;
+
+  /**
+   * External initial seed value. We do not care about multiple assignments so not volatile.
+   *
+   * @see #randomSeed64()
+   */
+  private static String testsSeedProperty;
+
+  /** Unique marker for {@link #testsSeedProperty}. */
+  private static final String NOT_AVAILABLE = new String();
+
+  private Containers() {}
+
+  /**
+   * Provides a (possibly) random initial seed for randomized stuff.
+   *
+   * <p>If <code>tests.seed</code> property is available and accessible, the returned value will be
+   * derived from the value of that property and will be constant to ensure reproducibility in
+   * presence of the randomized testing package.
+   *
+   * @see "https://github.com/carrotsearch/randomizedtesting"
+   */
+  @SuppressForbidden
+  public static long randomSeed64() {
+    if (testsSeedProperty == null) {
+      testsSeedProperty = System.getProperty("tests.seed", NOT_AVAILABLE);
+    }
+
+    long initialSeed;
+    if (testsSeedProperty != NOT_AVAILABLE) {
+      initialSeed = testsSeedProperty.hashCode();
+    } else {
+      // Mix something that is changing over time (nanoTime)
+      // ... with something that is thread-local and relatively unique
+      //     even for very short time-spans (new Object's address from a TLAB).
+      initialSeed = System.nanoTime() ^ System.identityHashCode(new Object());
+    }
+    return BitMixer.mix64(initialSeed);
+  }
+
+  /** Reset state for tests. */
+  static void test$reset() {
+    testsSeedProperty = null;
+  }
+}