Updated BinUtil and CoordinatePacker

- Added packing 2 ints into a long to CoordinatePacker
- Added iPowerOf2(int) to BinUtil

src/main/java/ru/windcorp/optica/common/util/BinUtil.java

@@ -32,4 +32,8 @@ public class BinUtil {
 		return closestGreaterPowerOf2(x - 1);
 	}
 	
+	public static boolean isPowerOf2(int x) {
+		return (x > 0) && ((x & (x - 1)) == 0);
+	}
+
 }

src/main/java/ru/windcorp/optica/common/util/CoordinatePacker.java

@@ -22,6 +22,9 @@ public class CoordinatePacker {
 	private static final int BITS_3_INTS_INTO_LONG;
 	private static final long MASK_3_INTS_INTO_LONG;
 	
+	private static final int BITS_2_INTS_INTO_LONG;
+	private static final long MASK_2_INTS_INTO_LONG;
+	
 	static {
 		BITS_3_INTS_INTO_LONG = 64 / 3;
 		
@@ -37,7 +40,10 @@ public class CoordinatePacker {
 		 *                \_________/ - BITS_3_INTS_INTO_LONG ones - WIN
 		 */
 		
-		MASK_3_INTS_INTO_LONG = (1 << BITS_3_INTS_INTO_LONG) - 1;
+		MASK_3_INTS_INTO_LONG = (1l << BITS_3_INTS_INTO_LONG) - 1;
+		
+		BITS_2_INTS_INTO_LONG = 64 / 2;
+		MASK_2_INTS_INTO_LONG = (1l << BITS_2_INTS_INTO_LONG) - 1;
 	}
 	
 	public static long pack3IntsIntoLong(int a, int b, int c) {
@@ -66,4 +72,23 @@ public class CoordinatePacker {
 		return result;
 	}
 	
+	public static long pack2IntsIntoLong(int a, int b) {
+		return
+				((a & MASK_2_INTS_INTO_LONG) << (1 * BITS_2_INTS_INTO_LONG)) |
+				((b & MASK_2_INTS_INTO_LONG) << (0 * BITS_2_INTS_INTO_LONG));
+	}
+	
+	public static int unpack2IntsFromLong(long packed, int index) {
+		if (index < 0 || index >= 2) {
+			throw new IllegalArgumentException("Invalid index " + index);
+		}
+		
+		int result = (int) (
+				(packed >>> ((1 - index) * BITS_2_INTS_INTO_LONG))
+				& MASK_2_INTS_INTO_LONG
+		);
+		
+		return result;
+	}
+
 }

src/test/java/ru/windcorp/optica/util/BinUtilIsPowerOf2Test.java

@@ -0,0 +1,72 @@
+/*******************************************************************************
+ * Optica
+ * Copyright (C) 2020  Wind Corporation
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *******************************************************************************/
+package ru.windcorp.optica.util;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Random;
+
+import org.junit.Test;
+
+import ru.windcorp.optica.common.util.BinUtil;
+
+public class BinUtilIsPowerOf2Test {
+	
+	@Test
+	public void cornerCases() {
+		test(-1);
+		test(0);
+		test(1);
+		
+		test(15);
+		test(16);
+		test(17);
+		
+		test(1 << 30);
+		test(Integer.MAX_VALUE);
+		test(Integer.MIN_VALUE);
+	}
+	
+	@Test
+	public void random() {
+		Random random = new Random(0);
+		
+		for (int x = 0; x < 10000; ++x) {
+			test(x);
+		}
+		
+		for (int i = 0; i < 10000; ++i) {
+			test(random.nextInt());
+		}
+	}
+	
+	void test(int x) {
+		assertEquals("Round, x = " + x, referenceIsPowerOf2(x), BinUtil.isPowerOf2(x));
+	}
+	
+	boolean referenceIsPowerOf2(int x) {
+		for (int power = 1; power > 0; power *= 2) {
+			if (x == power) {
+				return true;
+			}
+		}
+		
+		return false;
+	}
+
+}

src/test/java/ru/windcorp/optica/util/BinUtilRoundTest.java

@@ -25,7 +25,7 @@ import org.junit.Test;
 
 import ru.windcorp.optica.common.util.BinUtil;
 
-public class BinUtilTest {
+public class BinUtilRoundTest {
 	
 	@Test
 	public void cornerCases() {

src/test/java/ru/windcorp/optica/util/CoordinatePacker2Test.java

@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Optica
+ * Copyright (C) 2020  Wind Corporation
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *******************************************************************************/
+package ru.windcorp.optica.util;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Random;
+
+import org.junit.Test;
+
+import ru.windcorp.optica.common.util.CoordinatePacker;
+
+public class CoordinatePacker2Test {
+	
+	@Test
+	public void cornerCases() {
+		check(0, 0);
+		check(0, 42);
+		check(42, 0);
+		check(1, 1);
+		check(-1, -1);
+		
+		for (int a : new int[] {Integer.MAX_VALUE, Integer.MIN_VALUE, 0}) {
+			for (int b : new int[] {Integer.MAX_VALUE, Integer.MIN_VALUE, 0}) {
+				check(a, b);
+			}
+		}
+	}
+	
+	@Test
+	public void randomValues() {
+		Random random = new Random(0);;
+		
+		for (int i = 0; i < 1000000; ++i) {
+			check(
+					random.nextInt(),
+					random.nextInt()
+			);
+		}
+	}
+
+	private void check(int a, int b) {
+		
+		long packed = CoordinatePacker.pack2IntsIntoLong(a, b);
+		
+		int unpackedA = CoordinatePacker.unpack2IntsFromLong(packed, 0);
+		int unpackedB = CoordinatePacker.unpack2IntsFromLong(packed, 1);
+		
+		assertEquals(a, unpackedA);
+		assertEquals(b, unpackedB);
+		
+	}
+
+}

src/test/java/ru/windcorp/optica/util/CoordinatePacker3Test.java

@@ -25,7 +25,7 @@ import org.junit.Test;
 
 import ru.windcorp.optica.common.util.CoordinatePacker;
 
-public class CoordinatePackerTest {
+public class CoordinatePacker3Test {
 	
 	@Test
 	public void cornerCases() {