CFUtil varargs utils

Author: magicprinc

src/main/java/com/trivago/fastutilconcurrentwrapper/util/CFUtil.java

@@ -1,6 +1,7 @@
 package com.trivago.fastutilconcurrentwrapper.util;
 
 import it.unimi.dsi.fastutil.HashCommon;
+import it.unimi.dsi.fastutil.objects.ObjectArrays;
 import jakarta.validation.constraints.Positive;
 import jakarta.validation.constraints.PositiveOrZero;
 import lombok.AccessLevel;
@@ -75,4 +76,27 @@ Fast. Safe for negative keys (including Long.MIN_VALUE, Integer.MIN_VALUE)
 	public static long compoundKey (int keyHi, int keyLo) {
 		return ((long)keyHi << 32) | (keyLo & 0xFfFf_FfFfL);
 	}
+
+	/**
+	 Is varargs empty?
+	 @see #safeVarArgs
+	 */
+	public static boolean blankVarargs (@Nullable Object @Nullable [] args) {
+		return args == null
+				|| args.length == 0
+				|| (args.length == 1 && args[0] == null);
+	}
+
+	/// Fix usual varargs mistakes (but type is lost)
+	/// ~ Considers an Object array passed into a varargs parameter as collection of arguments rather than as single argument).
+	/// @see #blankVarargs
+	public static Object @Nullable[] safeVarArgs (@Nullable Object @Nullable[] varArgs) {
+		if (varArgs == null)
+				return ObjectArrays.EMPTY_ARRAY;// not some T[]!
+
+		if (varArgs.length == 1 && varArgs[0] instanceof Object[] a)// antT[] instanceof Object[]!
+				return a;
+
+		return varArgs;// usual good varargs
+	}
 }

src/test/java/com/trivago/fastutilconcurrentwrapper/intkey/PrimitiveConcurrentMapTest.java

@@ -2,6 +2,7 @@
 
 import com.trivago.fastutilconcurrentwrapper.PrimitiveConcurrentMap;
 import com.trivago.fastutilconcurrentwrapper.util.CFUtil;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import java.util.concurrent.ThreadLocalRandom;
@@ -43,7 +44,7 @@ void _hashLong () {
 		assertEquals(74720, CFUtil.bucket(Long.MAX_VALUE, 100_000));
 	}
 
-	@Test
+	@Test  @Disabled
 	void longsAreSame () {
 		long total = 0, t = System.nanoTime();
 		for (long i = Integer.MIN_VALUE; i <= Integer.MAX_VALUE; i++){

src/test/java/com/trivago/fastutilconcurrentwrapper/util/CFUtilTest.java

@@ -0,0 +1,48 @@
+package com.trivago.fastutilconcurrentwrapper.util;
+
+import it.unimi.dsi.fastutil.objects.ObjectArrays;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ @see CFUtil */
+class CFUtilTest {
+	@Test
+	void _hash () {
+		assertEquals(1832674720, CFUtil.hash(Integer.MIN_VALUE));
+		assertEquals(-2114883783, CFUtil.hash(-1));
+		assertEquals(0, CFUtil.hash(0));
+		assertEquals(1364076727, CFUtil.hash(1));
+		assertEquals(-104067416, CFUtil.hash(Integer.MAX_VALUE));
+	}
+
+	@Test
+	void _blankVarargs () {
+		assertTrue(CFUtil.blankVarargs(null));
+		assertTrue(CFUtil.blankVarargs((Object[])null));
+		assertTrue(CFUtil.blankVarargs(ObjectArrays.EMPTY_ARRAY));
+		assertTrue(CFUtil.blankVarargs(new String[]{null}));
+		assertTrue(CFUtil.blankVarargs(new Object[]{null}));
+
+		assertFalse(CFUtil.blankVarargs(new Object[]{null,null}));
+		assertFalse(CFUtil.blankVarargs(new Integer[]{1}));
+	}
+
+	@Test
+	void _safeVarArgs () {
+		Object[] a = null;
+
+		assertSame(ObjectArrays.EMPTY_ARRAY, CFUtil.safeVarArgs(null));
+		assertSame(ObjectArrays.EMPTY_ARRAY, CFUtil.safeVarArgs(a));
+		assertSame(ObjectArrays.EMPTY_ARRAY, CFUtil.safeVarArgs(ObjectArrays.EMPTY_ARRAY));
+
+		a = new Object[]{null};
+		assertSame(a, CFUtil.safeVarArgs(a));
+		a = new Integer[]{1};
+		assertSame(a, CFUtil.safeVarArgs(a));
+
+		a = new Integer[0];
+		assertSame(a, CFUtil.safeVarArgs(new Object[]{a}));
+	}
+}