Prepare for negative Y values

src/main/java/com/gmail/nossr50/listeners/BlockListener.java

@@ -148,10 +148,13 @@ public class BlockListener implements Listener {
         // Get opposite direction so we get correct block
         BlockFace direction = event.getDirection();
         Block movedBlock = event.getBlock().getRelative(direction);
-        mcMMO.getPlaceStore().setTrue(movedBlock);
+        if (movedBlock.getY() >= Misc.getWorldMinCompat(movedBlock.getWorld())) // Very weird that the event is giving us these, they shouldn't exist
+            mcMMO.getPlaceStore().setTrue(movedBlock);
 
         for (Block block : event.getBlocks()) {
             movedBlock = block.getRelative(direction);
+            if (movedBlock.getY() < Misc.getWorldMinCompat(movedBlock.getWorld())) // Very weird that the event is giving us these, they shouldn't exist
+                continue;
             mcMMO.getPlaceStore().setTrue(movedBlock);
         }
     }

src/main/java/com/gmail/nossr50/util/Misc.java

@@ -9,6 +9,7 @@ import com.gmail.nossr50.util.player.UserManager;
 import com.google.common.collect.ImmutableSet;
 import org.bukkit.Location;
 import org.bukkit.Material;
+import org.bukkit.World;
 import org.bukkit.block.BlockState;
 import org.bukkit.entity.*;
 import org.bukkit.inventory.ItemStack;
@@ -259,6 +260,12 @@ public final class Misc {
         }
     }
 
+    public static int getWorldMinCompat(World world)
+    {
+        // TODO this method should access the world min variable in a version safe manner so that we don't restrict usage to new versions of spigot only
+        return 0;
+    }
+
     public static void printProgress(int convertedUsers, int progressInterval, long startMillis) {
         if ((convertedUsers % progressInterval) == 0) {
             mcMMO.p.getLogger().info(String.format("Conversion progress: %d users at %.2f users/second", convertedUsers, convertedUsers / (double) ((System.currentTimeMillis() - startMillis) / TIME_CONVERSION_FACTOR)));

src/main/java/com/gmail/nossr50/util/blockmeta/BitSetChunkStore.java

@@ -1,5 +1,6 @@
 package com.gmail.nossr50.util.blockmeta;
 
+import com.gmail.nossr50.util.Misc;
 import org.bukkit.Bukkit;
 import org.bukkit.World;
 import org.jetbrains.annotations.NotNull;
@@ -10,12 +11,13 @@ import java.util.BitSet;
 import java.util.UUID;
 
 public class BitSetChunkStore implements ChunkStore {
-    private static final int CURRENT_VERSION = 8;
+    private static final int CURRENT_VERSION = 9;
     private static final int MAGIC_NUMBER = 0xEA5EDEBB;
 
     private final int cx;
     private final int cz;
-    private final int worldHeight;
+    private final int worldMin;
+    private final int worldMax;
     private final @NotNull UUID worldUid;
     // Bitset store conforms to a "bottom-up" bit ordering consisting of a stack of {worldHeight} Y planes, each Y plane consists of 16 Z rows of 16 X bits.
     private final @NotNull BitSet store;
@@ -23,15 +25,16 @@ public class BitSetChunkStore implements ChunkStore {
     private transient boolean dirty = false;
 
     public BitSetChunkStore(@NotNull World world, int cx, int cz) {
-        this(world.getUID(), world.getMaxHeight(), cx, cz);
+        this(world.getUID(), Misc.getWorldMinCompat(world), world.getMaxHeight(), cx, cz);
     }
 
-    private BitSetChunkStore(@NotNull UUID worldUid, int worldHeight, int cx, int cz) {
+    private BitSetChunkStore(@NotNull UUID worldUid, int worldMin, int worldMax, int cx, int cz) {
         this.cx = cx;
         this.cz = cz;
         this.worldUid = worldUid;
-        this.worldHeight = worldHeight;
-        this.store = new BitSet(16 * 16 * worldHeight);
+        this.worldMin = worldMin;
+        this.worldMax = worldMax;
+        this.store = new BitSet(16 * 16 * (worldMax - worldMin));
     }
 
     @Override
@@ -54,6 +57,16 @@ public class BitSetChunkStore implements ChunkStore {
         return cz;
     }
 
+    @Override
+    public int getChunkMin() {
+        return worldMin;
+    }
+
+    @Override
+    public int getChunkMax() {
+        return worldMax;
+    }
+
     @Override
     public @NotNull UUID getWorldId() {
         return worldUid;
@@ -86,22 +99,34 @@ public class BitSetChunkStore implements ChunkStore {
     }
 
     private int coordToIndex(int x, int y, int z) {
-        return coordToIndex(x, y, z, worldHeight);
+        return coordToIndex(x, y, z, worldMin, worldMax);
+    }
+
+    private static int coordToIndex(int x, int y, int z, int worldMin, int worldMax) {
+        if (x < 0 || x >= 16 || y < worldMin || y >= worldMax || z < 0 || z >= 16)
+            throw new IndexOutOfBoundsException(String.format("x: %d y: %d z: %d World Min: %d World Max: %d", x, y, z, worldMin, worldMax));
+        int yOffset = -worldMin; // Ensures y multiplier remains positive
+        return (z * 16 + x) + (256 * (y + yOffset));
     }
 
-    private static int coordToIndex(int x, int y, int z, int worldHeight) {
-        if (x < 0 || x >= 16 || y < 0 || y >= worldHeight || z < 0 || z >= 16)
-            throw new IndexOutOfBoundsException(String.format("x: %d y: %d z: %d World Height: %d", x, y, z, worldHeight));
-        return (z * 16 + x) + (256 * y);
+    private static int getWorldMin(@NotNull UUID worldUid, int storedWorldMin)
+    {
+        World world = Bukkit.getWorld(worldUid);
+
+        // Not sure how this case could come up, but might as well handle it gracefully.  Loading a chunkstore for an unloaded world?
+        if (world == null)
+            return storedWorldMin;
+
+        return Misc.getWorldMinCompat(world);
     }
 
-    private static int getWorldHeight(@NotNull UUID worldUid, int storedWorldHeight)
+    private static int getWorldMax(@NotNull UUID worldUid, int storedWorldMax)
     {
         World world = Bukkit.getWorld(worldUid);
 
         // Not sure how this case could come up, but might as well handle it gracefully.  Loading a chunkstore for an unloaded world?
         if (world == null)
-            return storedWorldHeight;
+            return storedWorldMax;
 
         return world.getMaxHeight();
     }
@@ -114,7 +139,8 @@ public class BitSetChunkStore implements ChunkStore {
         out.writeLong(worldUid.getMostSignificantBits());
         out.writeInt(cx);
         out.writeInt(cz);
-        out.writeInt(worldHeight);
+        out.writeInt(worldMin);
+        out.writeInt(worldMax);
 
         // Store the byte array directly so we don't have the object type info overhead
         byte[] storeData = store.toByteArray();
@@ -129,7 +155,7 @@ public class BitSetChunkStore implements ChunkStore {
         // Can be used to determine the format of the file
         int fileVersionNumber = in.readInt();
 
-        if (magic != MAGIC_NUMBER || fileVersionNumber != CURRENT_VERSION)
+        if (magic != MAGIC_NUMBER || fileVersionNumber < 8)
             throw new IOException();
 
         long lsb = in.readLong();
@@ -138,21 +164,38 @@ public class BitSetChunkStore implements ChunkStore {
         int cx = in.readInt();
         int cz = in.readInt();
 
-        int worldHeight = in.readInt();
+        int worldMin = 0;
+        if (fileVersionNumber >= 9)
+            worldMin = in.readInt();
+        int worldMax = in.readInt();
         byte[] temp = new byte[in.readInt()];
         in.readFully(temp);
         BitSet stored = BitSet.valueOf(temp);
 
-        int currentWorldHeight = getWorldHeight(worldUid, worldHeight);
-
-        boolean worldHeightShrunk = currentWorldHeight < worldHeight;
-        // Lop off extra data if world height has shrunk
-        if (worldHeightShrunk)
-            stored.clear(coordToIndex(16, currentWorldHeight, 16, worldHeight), stored.length());
+        int currentWorldMin = getWorldMin(worldUid, worldMin);
+        int currentWorldMax = getWorldMax(worldUid, worldMax);
+
+        // The order in which the world height update code occurs here is important, the world max truncate math only holds up if done before adjusting for min changes
+        // Lop off extra data if world max has shrunk
+        if (currentWorldMax < worldMax)
+            stored.clear(coordToIndex(16, currentWorldMax, 16, worldMin, worldMax), stored.length());
+        // Left shift store if world min has shrunk
+        if (currentWorldMin > worldMin)
+            stored = stored.get(currentWorldMin, stored.length()); // Because BitSet's aren't fixed size, a "substring" operation is equivalent to a left shift
+        // Right shift store if world min has expanded
+        if (currentWorldMin < worldMin)
+        {
+            int offset = (worldMin - currentWorldMin) * 16 * 16; // We are adding this many bits to the front
+            // This isn't the most efficient way to do this, however, its a rare case to occur, and in the grand scheme of things, the small performance we could gain would cost us significant reduced readability of the code
+            BitSet shifted = new BitSet();
+            for (int i = 0; i < stored.length(); i++)
+                shifted.set(i + offset, stored.get(i));
+            stored = shifted;
+        }
 
-        BitSetChunkStore chunkStore = new BitSetChunkStore(worldUid, currentWorldHeight, cx, cz);
+        BitSetChunkStore chunkStore = new BitSetChunkStore(worldUid, currentWorldMin, currentWorldMax, cx, cz);
         chunkStore.store.or(stored);
-        chunkStore.dirty = worldHeightShrunk; // In the expanded case there is no reason to re-write it unless the data changes
+        chunkStore.dirty = currentWorldMin != worldMin || currentWorldMax != worldMax;
 
         return chunkStore;
     }
@@ -203,7 +246,7 @@ public class BitSetChunkStore implements ChunkStore {
 
                 private int cx;
                 private int cz;
-                private int worldHeight;
+                private int worldMax;
                 private UUID worldUid;
                 private boolean[][][] store;
 
@@ -226,19 +269,20 @@ public class BitSetChunkStore implements ChunkStore {
                     cz = in.readInt();
 
                     store = (boolean[][][]) in.readObject();
-                    worldHeight = store[0][0].length;
+                    worldMax = store[0][0].length;
                 }
 
                 public @NotNull BitSetChunkStore convert()
                 {
-                    int currentWorldHeight = getWorldHeight(worldUid, worldHeight);
+                    int currentWorldMin = getWorldMin(worldUid, 0);
+                    int currentWorldMax = getWorldMax(worldUid, worldMax);
 
-                    BitSetChunkStore converted = new BitSetChunkStore(worldUid, currentWorldHeight, cx, cz);
+                    BitSetChunkStore converted = new BitSetChunkStore(worldUid, currentWorldMin, currentWorldMax, cx, cz);
 
                     // Read old data into new chunkstore
                     for (int x = 0; x < 16; x++) {
                         for (int z = 0; z < 16; z++) {
-                            for (int y = 0; y < worldHeight && y < currentWorldHeight; y++) {
+                            for (int y = 0; y < worldMax && y < currentWorldMax; y++) {
                                 converted.store.set(converted.coordToIndex(x, y, z), store[x][z][y]);
                             }
                         }

src/main/java/com/gmail/nossr50/util/blockmeta/ChunkStore.java

@@ -36,6 +36,9 @@ public interface ChunkStore {
      */
     int getChunkZ();
 
+    int getChunkMin();
+    int getChunkMax();
+
     @NotNull UUID getWorldId();
 
     /**

src/test/java/com/gmail/nossr50/util/blockmeta/ChunkStoreTest.java

@@ -1,6 +1,7 @@
 package com.gmail.nossr50.util.blockmeta;
 
 import com.gmail.nossr50.TestUtil;
+import com.gmail.nossr50.util.Misc;
 import com.google.common.io.Files;
 import org.bukkit.Bukkit;
 import org.bukkit.World;
@@ -22,7 +23,7 @@ import static org.mockito.Mockito.mock;
  * Could be a lot better.  But some tests are better than none!  Tests the major things, still kinda unit-testy.  Verifies that the serialization isn't completely broken.
  */
 @RunWith(PowerMockRunner.class)
-@PrepareForTest(Bukkit.class)
+@PrepareForTest({ Bukkit.class, Misc.class })
 public class ChunkStoreTest {
     private static File tempDir;
     @BeforeClass
@@ -76,6 +77,34 @@ public class ChunkStoreTest {
         assertEqual(original, deserialized);
     }
 
+    @Test
+    public void testNegativeWorldMin() throws IOException {
+        PowerMockito.mockStatic(Misc.class);
+        Mockito.when(Misc.getWorldMinCompat(mockWorld)).thenReturn(-64);
+
+        BitSetChunkStore original = new BitSetChunkStore(mockWorld, 1, 2);
+        original.setTrue(14, -32, 12);
+        original.setTrue(14, -64, 12);
+        original.setTrue(13, -63, 12);
+        byte[] serializedBytes = serializeChunkstore(original);
+        ChunkStore deserialized = BitSetChunkStore.Serialization.readChunkStore(new DataInputStream(new ByteArrayInputStream(serializedBytes)));
+        assertEqual(original, deserialized);
+    }
+
+    @Test
+    public void testNegativeWorldMinUpgrade() throws IOException {
+        BitSetChunkStore original = new BitSetChunkStore(mockWorld, 1, 2);
+        original.setTrue(14, 1, 12);
+        original.setTrue(14, 2, 12);
+        original.setTrue(13, 3, 12);
+        byte[] serializedBytes = serializeChunkstore(original);
+
+        PowerMockito.mockStatic(Misc.class);
+        Mockito.when(Misc.getWorldMinCompat(mockWorld)).thenReturn(-64);
+        ChunkStore deserialized = BitSetChunkStore.Serialization.readChunkStore(new DataInputStream(new ByteArrayInputStream(serializedBytes)));
+        assertEqualIgnoreMinMax(original, deserialized);
+    }
+
     @Test
     public void testChunkCoords() throws IOException {
         for (int x = -96; x < 0; x++) {
@@ -175,14 +204,25 @@ public class ChunkStoreTest {
     }
 
     private void assertEqual(ChunkStore expected, ChunkStore actual)
+    {
+        Assert.assertEquals(expected.getChunkMin(), actual.getChunkMin());
+        Assert.assertEquals(expected.getChunkMax(), actual.getChunkMax());
+        assertEqualIgnoreMinMax(expected, actual);
+    }
+
+    private void assertEqualIgnoreMinMax(ChunkStore expected, ChunkStore actual)
     {
         Assert.assertEquals(expected.getChunkX(), actual.getChunkX());
         Assert.assertEquals(expected.getChunkZ(), actual.getChunkZ());
         Assert.assertEquals(expected.getWorldId(), actual.getWorldId());
-        for (int y = 0; y < 256; y++)
+        for (int y = Math.min(actual.getChunkMin(), expected.getChunkMin()); y < Math.max(actual.getChunkMax(), expected.getChunkMax()); y++)
+        {
+            if (expected.getChunkMin() > y || actual.getChunkMin() > y || expected.getChunkMax() <= y || actual.getChunkMax() <= y)
+                continue; // Ignore
             for (int x = 0; x < 16; x++)
                 for (int z = 0; z < 16; z++)
                     Assert.assertTrue(expected.isTrue(x, y, z) == actual.isTrue(x, y, z));
+        }
     }
 
     private static byte[] serializeChunkstore(@NotNull ChunkStore chunkStore) throws IOException {
@@ -231,6 +271,16 @@ public class ChunkStoreTest {
             return cz;
         }
 
+        @Override
+        public int getChunkMin() {
+            return 0;
+        }
+
+        @Override
+        public int getChunkMax() {
+            return store[0][0].length;
+        }
+
         @Override
         public @NotNull UUID getWorldId() {
             return worldUid;