From d4785cda14d3f6906f47b3471f33534b57554eea Mon Sep 17 00:00:00 2001
From: DmitriyMX <dimon550@gmail.com>
Date: Sun, 12 Aug 2018 23:37:48 +0300
Subject: [PATCH] added CompactedCoords util

---
 .../java/mc/core/utils/CompactedCoords.java   | 23 ++++++++++
 .../mc/core/utils/TestCompactedCoords.java    | 45 +++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 core/src/main/java/mc/core/utils/CompactedCoords.java
 create mode 100644 core/src/test/java/mc/core/utils/TestCompactedCoords.java

diff --git a/core/src/main/java/mc/core/utils/CompactedCoords.java b/core/src/main/java/mc/core/utils/CompactedCoords.java
new file mode 100644
index 0000000..8a33b41
--- /dev/null
+++ b/core/src/main/java/mc/core/utils/CompactedCoords.java
@@ -0,0 +1,23 @@
+package mc.core.utils;
+
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class CompactedCoords {
+    public static int compressXZ(int x, int z) {
+        if (x < Short.MIN_VALUE || x > Short.MAX_VALUE ||
+                z < Short.MIN_VALUE || z > Short.MAX_VALUE) {
+            log.warn("Coord over range: [{},{}]", x, z);
+        }
+
+        return ((x & 0xFFFF) << 16) | (z & 0xFFFF);
+    }
+
+    public static int[] uncompressXZ(int compactValue) {
+        //TODO не нравится мне такие костыли
+        return new int[]{
+                (int)(short) (compactValue >> 16),
+                (int)(short) (compactValue | 0xFFFF0000)
+        };
+    }
+}
diff --git a/core/src/test/java/mc/core/utils/TestCompactedCoords.java b/core/src/test/java/mc/core/utils/TestCompactedCoords.java
new file mode 100644
index 0000000..4150c53
--- /dev/null
+++ b/core/src/test/java/mc/core/utils/TestCompactedCoords.java
@@ -0,0 +1,45 @@
+package mc.core.utils;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Random;
+
+
+public class TestCompactedCoords {
+    @Test
+    public void testSimple() {
+        for (int z = -100; z <= 100; z++) {
+            for (int x = -100; x <= 100; x++) {
+                int compressXZ = CompactedCoords.compressXZ(x, z);
+                int[] xz = CompactedCoords.uncompressXZ(compressXZ);
+
+                Assert.assertEquals(x, xz[0]);
+                Assert.assertEquals(z, xz[1]);
+            }
+        }
+    }
+
+    @Test
+    public void testRandom() {
+        Random random = new Random();
+        int x,z;
+
+        for (int i = 0; i < 100; i++) {
+            do {
+                x = random.nextInt();
+            } while (x < Short.MIN_VALUE || x > Short.MAX_VALUE);
+
+            do {
+                z = random.nextInt();
+            } while (z < Short.MIN_VALUE || z > Short.MAX_VALUE);
+
+
+            int compressXZ = CompactedCoords.compressXZ(x, z);
+            int[] xz = CompactedCoords.uncompressXZ(compressXZ);
+
+            Assert.assertEquals(x, xz[0]);
+            Assert.assertEquals(z, xz[1]);
+        }
+    }
+}