Yatopia/patches/server/0038-Highly-optimize-VillagePlace-filtering.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Ivan Pekov <ivan@mrivanplays.com>
Date: Thu, 27 Aug 2020 10:46:17 +0300
Subject: [PATCH] Highly optimize VillagePlace filtering

Replaced all streams I could. I expect this to be dropped in the next
major release and reimplemented again if mojang changes stuff with
villagers again.

diff --git a/src/main/java/me/jellysquid/mods/lithium/common/util/Producer.java b/src/main/java/me/jellysquid/mods/lithium/common/util/Producer.java
index f3224ea636fef95d368b934ed4b3e9060c4b10a2..f2d5878d235fdbfc11c74f87b95f029330c70309 100644
--- a/src/main/java/me/jellysquid/mods/lithium/common/util/Producer.java
+++ b/src/main/java/me/jellysquid/mods/lithium/common/util/Producer.java
@@ -46,6 +46,16 @@ public interface Producer<T> {
         }
     }
 
+    // also checks contains and is thus only 1 generic
+    static <T> void fillList(Producer<T> producer, List<T> list) {
+        HoldingConsumer<T> consumer = new HoldingConsumer<>();
+        while (producer.computeNext(consumer)) {
+            T value = consumer.getValue();
+            if (value == null || list.contains(value)) { continue; }
+            list.add(value);
+        }
+    }
+
     Producer<?> EMPTY_PRODUCER = consumer -> false;
 
     @SuppressWarnings("unchecked")
diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
index 6fcc7ed7c129e6a33386d65b37cbba4a44e96f0f..dbe6f7d555e8c851faba5cafee8831c516256c09 100644
--- a/src/main/java/net/minecraft/server/BlockPosition.java
+++ b/src/main/java/net/minecraft/server/BlockPosition.java
@@ -341,6 +341,16 @@ public class BlockPosition extends BaseBlockPosition {
         return a(MathHelper.floor(axisalignedbb.minX), MathHelper.floor(axisalignedbb.minY), MathHelper.floor(axisalignedbb.minZ), MathHelper.floor(axisalignedbb.maxX), MathHelper.floor(axisalignedbb.maxY), MathHelper.floor(axisalignedbb.maxZ));
     }
 
+    // Yatopia start
+    public static java.util.List<BlockPosition> getPositions(int i, int j, int k, int l, int i1, int j1) {
+        java.util.List<BlockPosition> ret = new net.yatopia.server.list.GlueList<>();
+        Iterable<BlockPosition> iterable = b(i, j, k, l, i1, j1);
+        net.yatopia.server.HoldingConsumer<BlockPosition> consumer = new net.yatopia.server.HoldingConsumer<>();
+        java.util.Spliterator<BlockPosition> spliterator = iterable.spliterator();
+        while (spliterator.tryAdvance(consumer)) ret.add(consumer.getValue());
+        return ret;
+    }
+    // Yatopia end
     public static Stream<BlockPosition> a(int i, int j, int k, int l, int i1, int j1) {
         return StreamSupport.stream(b(i, j, k, l, i1, j1).spliterator(), false);
     }
diff --git a/src/main/java/net/minecraft/server/ChunkCoordIntPair.java b/src/main/java/net/minecraft/server/ChunkCoordIntPair.java
index dcaf9f8574a9c913b64ba3a1d8b02220db720225..3df4ae0f0921670c19abe17a115da428b4a1f534 100644
--- a/src/main/java/net/minecraft/server/ChunkCoordIntPair.java
+++ b/src/main/java/net/minecraft/server/ChunkCoordIntPair.java
@@ -116,6 +116,15 @@ public class ChunkCoordIntPair {
         return a(new ChunkCoordIntPair(chunkcoordintpair.x - i, chunkcoordintpair.z - i), new ChunkCoordIntPair(chunkcoordintpair.x + i, chunkcoordintpair.z + i));
     }
 
+    // Yatopia start
+    public static java.util.List<ChunkCoordIntPair> streamList(ChunkCoordIntPair center, int radius) {
+        return streamList(new ChunkCoordIntPair(center.x - radius, center.z - radius), new ChunkCoordIntPair(center.x + radius, center.z + radius));
+    }
+    public static java.util.List<ChunkCoordIntPair> streamList(ChunkCoordIntPair pos1, ChunkCoordIntPair pos2) {
+        return net.yatopia.server.YatopiaChunkPos.asList(pos1, pos2);
+    }
+    // Yatopia end
+
     public static Stream<ChunkCoordIntPair> a(final ChunkCoordIntPair chunkcoordintpair, final ChunkCoordIntPair chunkcoordintpair1) {
         int i = Math.abs(chunkcoordintpair.x - chunkcoordintpair1.x) + 1;
         int j = Math.abs(chunkcoordintpair.z - chunkcoordintpair1.z) + 1;
diff --git a/src/main/java/net/minecraft/server/EntityBee.java b/src/main/java/net/minecraft/server/EntityBee.java
index f73641ddb3e82bc653732105ef0a3d41a28e845f..f1d6239b834498dc12c1674b3e776d0c15215568 100644
--- a/src/main/java/net/minecraft/server/EntityBee.java
+++ b/src/main/java/net/minecraft/server/EntityBee.java
@@ -720,15 +720,24 @@ public class EntityBee extends EntityAnimal implements IEntityAngerable, EntityB
         private List<BlockPosition> j() {
             BlockPosition blockposition = EntityBee.this.getChunkCoordinates();
             VillagePlace villageplace = ((WorldServer) EntityBee.this.world).y();
-            Stream<VillagePlaceRecord> stream = villageplace.c((villageplacetype) -> {
+            List<VillagePlaceRecord> stream = villageplace.cList((villageplacetype) -> { // Yatopia
                 return villageplacetype == VillagePlaceType.t || villageplacetype == VillagePlaceType.u;
             }, blockposition, 20, VillagePlace.Occupancy.ANY);
-
+            // Yatopia start
+            List<BlockPosition> ret = new net.yatopia.server.list.GlueList<>();
+            for (VillagePlaceRecord record : stream) {
+                BlockPosition pos = record.getPosition();
+                if (i(pos)) { ret.add(pos); }
+            }
+            ret.sort(Comparator.comparingDouble((pos1) -> pos1.distanceSquared(blockposition)));
+            return ret;
+            /*
             return (List) stream.map(VillagePlaceRecord::f).filter((blockposition1) -> {
                 return EntityBee.this.i(blockposition1);
             }).sorted(Comparator.comparingDouble((blockposition1) -> {
                 return blockposition1.j(blockposition);
             })).collect(Collectors.toList());
+             */ // Yatopia end
         }
     }
 
diff --git a/src/main/java/net/minecraft/server/PersistentRaid.java b/src/main/java/net/minecraft/server/PersistentRaid.java
index 826dcf9f7eedc3664d66170b97b2a19552a0dc60..81f9b2ec160a015ce7e82ba33dd684e0b3932877 100644
--- a/src/main/java/net/minecraft/server/PersistentRaid.java
+++ b/src/main/java/net/minecraft/server/PersistentRaid.java
@@ -68,7 +68,7 @@ public class PersistentRaid extends PersistentBase {
                 return null;
             } else {
                 BlockPosition blockposition = entityplayer.getChunkCoordinates();
-                List<VillagePlaceRecord> list = (List) this.b.y().c(VillagePlaceType.b, blockposition, 64, VillagePlace.Occupancy.IS_OCCUPIED).collect(Collectors.toList());
+                List<VillagePlaceRecord> list = this.b.y().cList(VillagePlaceType.b, blockposition, 64, VillagePlace.Occupancy.IS_OCCUPIED); // Yatopia
                 int i = 0;
                 Vec3D vec3d = Vec3D.ORIGIN;
 
diff --git a/src/main/java/net/minecraft/server/PortalTravelAgent.java b/src/main/java/net/minecraft/server/PortalTravelAgent.java
index eddf3dff9a00bf3c7318745e52befd4c04fa2af7..c47dc39dcdacbefa07c69f04601f7a125cfbb25c 100644
--- a/src/main/java/net/minecraft/server/PortalTravelAgent.java
+++ b/src/main/java/net/minecraft/server/PortalTravelAgent.java
@@ -29,7 +29,7 @@ public class PortalTravelAgent {
             return villageplacerecord.f().getY();
         }); // Yatopia
         // Yatopia start
-        java.util.List<VillagePlaceRecord> list = villageplace.b(type -> type == VillagePlaceType.v, blockposition, i, VillagePlace.Occupancy.ANY).collect(java.util.stream.Collectors.toList());
+        java.util.List<VillagePlaceRecord> list = villageplace.bList(type -> type == VillagePlaceType.v, blockposition, i, VillagePlace.Occupancy.ANY);
         if (world.origamiConfig.useBlockDistanceInPortalSearchRadius) {
             list.removeIf(villagePlaceRecord -> {
                 BlockPosition portalPosition = villagePlaceRecord.getPosition();
diff --git a/src/main/java/net/minecraft/server/SectionPosition.java b/src/main/java/net/minecraft/server/SectionPosition.java
index f95925f1c5d091f1a129d0437bb6e175c6ac080f..6796b1a832779b65d337c63d6b600e2a3b5e9559 100644
--- a/src/main/java/net/minecraft/server/SectionPosition.java
+++ b/src/main/java/net/minecraft/server/SectionPosition.java
@@ -159,6 +159,7 @@ public class SectionPosition extends BaseBlockPosition {
         return this.p().b(8, 8, 8);
     }
 
+    public final ChunkCoordIntPair asChunkPos() { return r(); } // Yatopia - OBFHELPER
     public ChunkCoordIntPair r() {
         return new ChunkCoordIntPair(this.a(), this.c());
     }
@@ -173,10 +174,12 @@ public class SectionPosition extends BaseBlockPosition {
         return (((long) i & 4194303L) << 42) | (((long) j & 1048575L)) | (((long) k & 4194303L) << 20); // Paper - Simplify to reduce instruction count
     }
 
+    public final long asLong() { return s(); } // Yatopia - OBFHELPER
     public long s() {
         return (((long) getX() & 4194303L) << 42) | (((long) getY() & 1048575L)) | (((long) getZ() & 4194303L) << 20); // Paper - Simplify to reduce instruction count
     }
 
+    public java.util.List<BlockPosition> tList() { return BlockPosition.getPositions(d(), e(), f(), g(), h(), i()); } // Yatopia
     public Stream<BlockPosition> t() {
         return BlockPosition.a(this.d(), this.e(), this.f(), this.g(), this.h(), this.i());
     }
@@ -189,6 +192,18 @@ public class SectionPosition extends BaseBlockPosition {
         return a(chunkcoordintpair.x - i, 0, chunkcoordintpair.z - i, chunkcoordintpair.x + i, 15, chunkcoordintpair.z + i); // Paper - simplify/inline
     }
 
+    // Yatopia start
+    public static java.util.List<SectionPosition> getPosList(SectionPosition pos, int i) {
+        return getPosList(pos.getX() - i, pos.getY() - i, pos.getZ() - i, pos.getX() + i, pos.getY() + i, pos.getZ() + i);
+    }
+    public static java.util.List<SectionPosition> getPosList(ChunkCoordIntPair chunkPos, int i) {
+        return getPosList(chunkPos.x - i, 0, chunkPos.z - i, chunkPos.x + i, 15, chunkPos.z + i);
+    }
+    public static java.util.List<SectionPosition> getPosList(int i, int j, int k, int l, int i1, int j1) {
+        return net.yatopia.server.YatopiaChunkSectionPos.getChunkSectionPosList(i, j, k, l,  i1, j1);
+    }
+    // Yatopia end
+
     public static Stream<SectionPosition> a(final int i, final int j, final int k, final int l, final int i1, final int j1) {
         return StreamSupport.stream(new AbstractSpliterator<SectionPosition>((long) ((l - i + 1) * (i1 - j + 1) * (j1 - k + 1)), 64) {
             final CursorPosition a = new CursorPosition(i, j, k, l, i1, j1);
diff --git a/src/main/java/net/minecraft/server/VillagePlace.java b/src/main/java/net/minecraft/server/VillagePlace.java
index 3c9668c9c30ea57c1608e32ece27ec56d580fc62..70337f6eb2b868e0c05be12a90471a86664ac3df 100644
--- a/src/main/java/net/minecraft/server/VillagePlace.java
+++ b/src/main/java/net/minecraft/server/VillagePlace.java
@@ -46,7 +46,7 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
     }
 
     public long a(Predicate<VillagePlaceType> predicate, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
-        return this.c(predicate, blockposition, i, villageplace_occupancy).count();
+        return this.cList(predicate, blockposition, i, villageplace_occupancy).size(); // Yatopia
     }
 
     public boolean a(VillagePlaceType villageplacetype, BlockPosition blockposition) {
@@ -67,6 +67,29 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
         });
     }
 
+    // Yatopia start
+    public java.util.List<VillagePlaceRecord> bList(Predicate<VillagePlaceType> filter, BlockPosition pos, int i, VillagePlace.Occupancy occupancy) {
+        int j = Math.floorDiv(i, 16) + 1;
+
+        java.util.List<ChunkCoordIntPair> list = ChunkCoordIntPair.streamList(new ChunkCoordIntPair(pos), j);
+        java.util.List<VillagePlaceRecord> ret = new net.yatopia.server.list.GlueList<>();
+        for (ChunkCoordIntPair chunkPos : list) {
+            for (int k = 0; k < 16; k++) { // ITS THE LAW
+                this.d(SectionPosition.a(chunkPos, k).asLong()).ifPresent(section -> ret.addAll(section.aList(filter, occupancy)));
+            }
+        }
+        return ret;
+    }
+    public java.util.List<VillagePlaceRecord> cList(Predicate<VillagePlaceType> predicate, BlockPosition pos, int i, VillagePlace.Occupancy occupancy) {
+        int j = i * i;
+        java.util.List<VillagePlaceRecord> ret = new net.yatopia.server.list.GlueList<>();
+        for (VillagePlaceRecord record : this.bList(predicate, pos, i, occupancy)) {
+            if (record.getPosition().distanceSquared(pos) <= j) { ret.add(record); }
+        }
+        return ret;
+    }
+    // Yatopia end
+
     public Stream<VillagePlaceRecord> c(Predicate<VillagePlaceType> predicate, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
         int j = i * i;
 
@@ -83,10 +106,28 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
         });
     }
 
+    // Yatopia start
+    public java.util.List<BlockPosition> aList(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> posFilter, BlockPosition pos, int i, VillagePlace.Occupancy occupancy) {
+        java.util.List<BlockPosition> ret = new net.yatopia.server.list.GlueList<>();
+        int j = i * i;
+        for (VillagePlaceRecord record : this.bList(predicate, pos, i, occupancy)) {
+            BlockPosition recordPosition = record.getPosition();
+            if (recordPosition.distanceSquared(pos) <= j && posFilter.test(recordPosition)) { ret.add(recordPosition); }
+        }
+        return ret;
+    }
+    // Yatopia end
     public Stream<BlockPosition> a(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> predicate1, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
         return this.c(predicate, blockposition, i, villageplace_occupancy).map(VillagePlaceRecord::f).filter(predicate1);
     }
 
+    // Yatopia start
+    public java.util.List<BlockPosition> bList(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> posFilter, BlockPosition pos, int i, VillagePlace.Occupancy occupancy) {
+        java.util.List<BlockPosition> ret = aList(predicate, posFilter, pos, i, occupancy);
+        ret.sort(Comparator.comparingDouble((pos1) -> pos1.distanceSquared(pos)));
+        return ret;
+    }
+    // Yatopia end
     public Stream<BlockPosition> b(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> predicate1, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
         return this.a(predicate, predicate1, blockposition, i, villageplace_occupancy).sorted(Comparator.comparingDouble((blockposition1) -> {
             return blockposition1.j(blockposition);
@@ -94,31 +135,68 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
     }
 
     public Optional<BlockPosition> c(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> predicate1, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
-        return this.a(predicate, predicate1, blockposition, i, villageplace_occupancy).findFirst();
+        // Yatopia start
+        for (VillagePlaceRecord record : this.cList(predicate, blockposition, i, villageplace_occupancy)) {
+            BlockPosition recordPosition = record.getPosition();
+            if (predicate1.test(recordPosition)) return Optional.of(recordPosition);
+        }
+        return Optional.empty();
+        // Yatopia end
     }
 
     public Optional<BlockPosition> d(Predicate<VillagePlaceType> predicate, BlockPosition blockposition, int i, VillagePlace.Occupancy villageplace_occupancy) {
+        // Yatopia start
+        VillagePlaceRecord best = null;
+        for (VillagePlaceRecord record : cList(predicate, blockposition, i, villageplace_occupancy)) {
+            BlockPosition recordPos = record.getPosition();
+            if (best == null || (recordPos.distanceSquared(blockposition) < best.getPosition().distanceSquared(blockposition))) {
+                best = record;
+            }
+        }
+        return best == null ? Optional.empty() : Optional.of(best.getPosition());
+        /*
         return this.c(predicate, blockposition, i, villageplace_occupancy).map(VillagePlaceRecord::f).min(Comparator.comparingDouble((blockposition1) -> {
             return blockposition1.j(blockposition);
         }));
+         */ // Yatopia end
     }
 
     public Optional<BlockPosition> a(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> predicate1, BlockPosition blockposition, int i) {
+        // Yatopia start
+        int j = i * i;
+        for (VillagePlaceRecord record : this.bList(predicate, blockposition, i, VillagePlace.Occupancy.HAS_SPACE)) {
+            BlockPosition recordPos = record.getPosition();
+            if (recordPos.distanceSquared(blockposition) <= j && predicate1.test(recordPos)) {
+                record.b();
+                return Optional.of(recordPos);
+            }
+        }
+        return Optional.empty();
+        /*
         return this.c(predicate, blockposition, i, VillagePlace.Occupancy.HAS_SPACE).filter((villageplacerecord) -> {
             return predicate1.test(villageplacerecord.f());
         }).findFirst().map((villageplacerecord) -> {
             villageplacerecord.b();
             return villageplacerecord.f();
         });
+        */ // Yatopia end
     }
 
     public Optional<BlockPosition> a(Predicate<VillagePlaceType> predicate, Predicate<BlockPosition> predicate1, VillagePlace.Occupancy villageplace_occupancy, BlockPosition blockposition, int i, Random random) {
-        List<VillagePlaceRecord> list = (List) this.c(predicate, blockposition, i, villageplace_occupancy).collect(Collectors.toList());
+        List<VillagePlaceRecord> list = this.cList(predicate, blockposition, i, villageplace_occupancy); // Yatopia
 
         Collections.shuffle(list, random);
+        // Yatopia start - replace stream
+        for (VillagePlaceRecord record : list) {
+            BlockPosition recordPosition = record.getPosition();
+            if (predicate1.test(recordPosition)) return Optional.of(recordPosition);
+        }
+        return Optional.empty();
+        /*
         return list.stream().filter((villageplacerecord) -> {
             return predicate1.test(villageplacerecord.f());
         }).findFirst().map(VillagePlaceRecord::f);
+         */
     }
 
     public boolean b(BlockPosition blockposition) {
@@ -211,7 +289,7 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
     }
 
     private void a(ChunkSection chunksection, SectionPosition sectionposition, BiConsumer<BlockPosition, VillagePlaceType> biconsumer) {
-        sectionposition.t().forEach((blockposition) -> {
+        sectionposition.tList().forEach((blockposition) -> { // Yatopia
             IBlockData iblockdata = chunksection.getType(SectionPosition.b(blockposition.getX()), SectionPosition.b(blockposition.getY()), SectionPosition.b(blockposition.getZ()));
 
             VillagePlaceType.b(iblockdata).ifPresent((villageplacetype) -> {
@@ -221,6 +299,16 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
     }
 
     public void a(IWorldReader iworldreader, BlockPosition blockposition, int i) {
+        // Yatopia start - WHY?
+        java.util.List<SectionPosition> posList = SectionPosition.getPosList(new ChunkCoordIntPair(blockposition), Math.floorDiv(i, 16));
+        for (SectionPosition pos : posList) {
+            boolean shouldContinue = this.d(pos.asLong()).map(VillagePlaceSection::a).orElse(false);
+            if (shouldContinue) {
+                ChunkCoordIntPair chunkPos = pos.asChunkPos();
+                if (b.add(chunkPos.pair())) { iworldreader.getChunkAt(chunkPos.x, chunkPos.z, ChunkStatus.EMPTY); }
+            }
+        }
+        /*
         SectionPosition.b(new ChunkCoordIntPair(blockposition), Math.floorDiv(i, 16)).map((sectionposition) -> {
             return Pair.of(sectionposition, this.d(sectionposition.s()));
         }).filter((pair) -> {
@@ -232,6 +320,7 @@ public class VillagePlace extends RegionFileSection<VillagePlaceSection> {
         }).forEach((chunkcoordintpair) -> {
             iworldreader.getChunkAt(chunkcoordintpair.x, chunkcoordintpair.z, ChunkStatus.EMPTY);
         });
+         */ // Yatopia end
     }
 
     final class a extends LightEngineGraphSection {
diff --git a/src/main/java/net/minecraft/server/VillagePlaceSection.java b/src/main/java/net/minecraft/server/VillagePlaceSection.java
index f43bc1f7d693d63c6bbdba976c048d2d0c8767b1..5e8297d096c2f2eae449801848422287051f146f 100644
--- a/src/main/java/net/minecraft/server/VillagePlaceSection.java
+++ b/src/main/java/net/minecraft/server/VillagePlaceSection.java
@@ -55,6 +55,17 @@ public class VillagePlaceSection {
         list.forEach(this::a);
     }
 
+    // Yatopia start
+    public java.util.List<VillagePlaceRecord> aList(Predicate<VillagePlaceType> predicate, VillagePlace.Occupancy occupancy) {
+        java.util.List<VillagePlaceRecord> ret = new net.yatopia.server.list.GlueList<>();
+        for (Map.Entry<VillagePlaceType, Set<VillagePlaceRecord>> entry : c.entrySet()) {
+            if (predicate.test(entry.getKey())) {
+                for (VillagePlaceRecord record : entry.getValue()) { if (occupancy.a().test(record)) ret.add(record); }
+            }
+        }
+        return ret;
+    }
+    // Yatopia end
     public Stream<VillagePlaceRecord> a(Predicate<VillagePlaceType> predicate, VillagePlace.Occupancy villageplace_occupancy) {
         return this.c.entrySet().stream().filter((entry) -> {
             return predicate.test(entry.getKey());
diff --git a/src/main/java/net/yatopia/server/YatopiaChunkPos.java b/src/main/java/net/yatopia/server/YatopiaChunkPos.java
new file mode 100644
index 0000000000000000000000000000000000000000..871e305356103f87c2c1ad1487c804b60e13c076
--- /dev/null
+++ b/src/main/java/net/yatopia/server/YatopiaChunkPos.java
@@ -0,0 +1,54 @@
+package net.yatopia.server;
+
+import java.util.List;
+import java.util.function.Consumer;
+import me.jellysquid.mods.lithium.common.util.Producer;
+import net.minecraft.server.ChunkCoordIntPair;
+import net.yatopia.server.list.GlueList;
+
+public class YatopiaChunkPos {
+
+    public static List<ChunkCoordIntPair> asList(ChunkCoordIntPair pos1, ChunkCoordIntPair pos2) {
+        List<ChunkCoordIntPair> list = new GlueList<>();
+        Producer.fillList(getStreamProducer(pos1, pos2), list);
+        return list;
+    }
+
+    /**
+     * [VanillaCopy] but in a producer
+     *
+     * @param pos1 pos 1
+     * @param pos2 pos 2
+     * @return producer
+     */
+    private static Producer<ChunkCoordIntPair> getStreamProducer(ChunkCoordIntPair pos1, ChunkCoordIntPair pos2) {
+        final int k = pos1.x < pos2.x ? 1 : -1;
+        final int l = pos1.z < pos2.z ? 1 : -1;
+
+        return new Producer<ChunkCoordIntPair>() {
+            private ChunkCoordIntPair pair = null;
+
+            @Override
+            public boolean computeNext(Consumer<? super ChunkCoordIntPair> consumer) {
+                if (pair == null) {
+                    pair = pos1;
+                } else {
+                    int i1 = this.pair.x;
+                    int j1 = this.pair.z;
+
+                    if (i1 == pos2.x) {
+                        if (j1 == pos2.z) {
+                            return false;
+                        }
+
+                        this.pair = new ChunkCoordIntPair(pos1.x, j1 + l);
+                    } else {
+                        this.pair = new ChunkCoordIntPair(i1 + k, j1);
+                    }
+                }
+                consumer.accept(pair);
+                return true;
+            }
+        };
+    }
+}
diff --git a/src/main/java/net/yatopia/server/YatopiaChunkSectionPos.java b/src/main/java/net/yatopia/server/YatopiaChunkSectionPos.java
new file mode 100644
index 0000000000000000000000000000000000000000..134c761c7897f37c20b5209866374dd79dc5b0e4
--- /dev/null
+++ b/src/main/java/net/yatopia/server/YatopiaChunkSectionPos.java
@@ -0,0 +1,32 @@
+package net.yatopia.server;
+
+import java.util.List;
+import java.util.function.Consumer;
+import me.jellysquid.mods.lithium.common.util.Producer;
+import net.minecraft.server.CursorPosition;
+import net.minecraft.server.SectionPosition;
+import net.yatopia.server.list.GlueList;
+
+public class YatopiaChunkSectionPos {
+
+    public static List<SectionPosition> getChunkSectionPosList(int i, int j, int k, int l, int i1, int j1) {
+        List<SectionPosition> list = new GlueList<>();
+        Producer.fillList(getChunkSectionPosProducer(i, j, k, l, i1, j1), list);
+        return list;
+    }
+
+    private static Producer<SectionPosition> getChunkSectionPosProducer(int i, int j, int k, int l, int i1, int j1) {
+        return new Producer<SectionPosition>() {
+            final CursorPosition cursorPos = new CursorPosition(i, j, k, l, i1, j1);
+
+            @Override
+            public boolean computeNext(Consumer<? super SectionPosition> consumer) {
+                if (cursorPos.a()) {
+                    consumer.accept(SectionPosition.a(cursorPos.b(), cursorPos.c(), cursorPos.d()));
+                    return true;
+                }
+                return false;
+            }
+        };
+    }
+}