Memory optimizations (#505)

* Remove LocatedBlock overhead in LBL map

* Add new space-efficient block map, with thourough testing

* Drop ordering property, add full insertion test

* Add licenses

* Fix mocked platform conflicts

* Disable full block map testing for faster builds

* Re-implement BlockMap with fastutil maps

* Re-write chunk batching to be memory efficient

* Make MultiStageReorder use BlockMap

* Increase LBL load factor, fix long-pack limit detection

* Fix infinite loop in chunk batching

* Save memory in history by cleaning up MSR

* Re-implement LocatedBlockList in BlockMap

* Fix data race with BlockType lazy fields

* Make IDs ALWAYS present, only runtime-consistent. Use for memory efficiency in BlockMap

* Remap inner structure of BlockMap for smaller maps

* Remove containedBlocks fields, not very efficient

* Fix minor de-optimizing bug in stage reorder

* Make long packed y signed

* Add extended Y limit configuration option

* Add licenses

* Store 3 ints for unoptimized BV list

* Add final to BitMath

* Correct int-cast for long-packing

worldedit-core/src/main/java/com/sk89q/worldedit/math/BitMath.java

@@ -0,0 +1,52 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.math;
+
+public final class BitMath {
+
+    public static int mask(int bits) {
+        return ~(~0 << bits);
+    }
+
+    public static int unpackX(long packed) {
+        return extractSigned(packed, 0, 26);
+    }
+
+    public static int unpackZ(long packed) {
+        return extractSigned(packed, 26, 26);
+    }
+
+    public static int unpackY(long packed) {
+        return extractSigned(packed, 26 + 26, 12);
+    }
+
+    public static int extractSigned(long i, int shift, int bits) {
+        return fixSign((int) (i >> shift) & mask(bits), bits);
+    }
+
+    public static int fixSign(int i, int bits) {
+        // Using https://stackoverflow.com/a/29266331/436524
+        return i << (32 - bits) >> (32 - bits);
+    }
+
+    private BitMath() {
+    }
+
+}

worldedit-core/src/main/java/com/sk89q/worldedit/math/BlockVector3.java

@@ -24,6 +24,10 @@ import com.sk89q.worldedit.math.transform.AffineTransform;
 import java.util.Comparator;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static com.sk89q.worldedit.math.BitMath.mask;
+import static com.sk89q.worldedit.math.BitMath.unpackX;
+import static com.sk89q.worldedit.math.BitMath.unpackY;
+import static com.sk89q.worldedit.math.BitMath.unpackZ;
 
 /**
  * An immutable 3-dimensional vector.
@@ -61,6 +65,31 @@ public final class BlockVector3 {
         return new BlockVector3(x, y, z);
     }
 
+    private static final int WORLD_XZ_MINMAX = 30_000_000;
+    private static final int WORLD_Y_MAX = 4095;
+
+    private static boolean isHorizontallyInBounds(int h) {
+        return -WORLD_XZ_MINMAX <= h && h <= WORLD_XZ_MINMAX;
+    }
+
+    public static boolean isLongPackable(BlockVector3 location) {
+        return isHorizontallyInBounds(location.getX()) &&
+            isHorizontallyInBounds(location.getZ()) &&
+            0 <= location.getY() && location.getY() <= WORLD_Y_MAX;
+    }
+
+    public static void checkLongPackable(BlockVector3 location) {
+        checkArgument(isLongPackable(location),
+            "Location exceeds long packing limits: %s", location);
+    }
+
+    private static final long BITS_26 = mask(26);
+    private static final long BITS_12 = mask(12);
+
+    public static BlockVector3 fromLongPackedForm(long packed) {
+        return at(unpackX(packed), unpackY(packed), unpackZ(packed));
+    }
+
     // thread-safe initialization idiom
     private static final class YzxOrderComparator {
         private static final Comparator<BlockVector3> YZX_ORDER =
@@ -94,6 +123,11 @@ public final class BlockVector3 {
         this.z = z;
     }
 
+    public long toLongPackedForm() {
+        checkLongPackable(this);
+        return (x & BITS_26) | ((z & BITS_26) << 26) | (((y & (long) BITS_12) << (26 + 26)));
+    }
+
     /**
      * Get the X coordinate.
      *

worldedit-core/src/main/java/com/sk89q/worldedit/math/RegionOptimizedChunkComparator.java

@@ -0,0 +1,41 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.math;
+
+import java.util.Comparator;
+
+import static com.sk89q.worldedit.math.BlockVector2.COMPARING_GRID_ARRANGEMENT;
+
+/**
+ * Sort block positions by region, then chunk.
+ */
+public class RegionOptimizedChunkComparator {
+
+    private static final Comparator<BlockVector2> CHUNK_COMPARATOR =
+        Comparator.comparing((BlockVector2 chunkPos) -> chunkPos.shr(5), COMPARING_GRID_ARRANGEMENT)
+            .thenComparing(COMPARING_GRID_ARRANGEMENT);
+
+    public static final Comparator<BlockVector3> INSTANCE
+        = Comparator.comparing(blockPos -> blockPos.toBlockVector2().shr(4), CHUNK_COMPARATOR);
+
+    private RegionOptimizedChunkComparator() {
+    }
+
+}

worldedit-core/src/main/java/com/sk89q/worldedit/math/RegionOptimizedComparator.java

@@ -0,0 +1,36 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.math;
+
+import java.util.Comparator;
+
+/**
+ * Sort block positions by region, chunk, and finally Y-Z-X.
+ */
+public class RegionOptimizedComparator {
+
+    public static final Comparator<BlockVector3> INSTANCE
+        = RegionOptimizedChunkComparator.INSTANCE
+        .thenComparing(BlockVector3.sortByCoordsYzx());
+
+    private RegionOptimizedComparator() {
+    }
+
+}