From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: JRoy <joshroy126@gmail.com>
Date: Mon, 29 Jun 2020 17:03:06 -0400
Subject: [PATCH] Remove some streams from structures

This showed up a lot in the spark profiler, should have a low-medium performance improvement.

diff --git a/src/main/java/net/minecraft/world/level/StructureManager.java b/src/main/java/net/minecraft/world/level/StructureManager.java
index 6fe276b29aa9fe1b312ef2773484fa780506fded..07dcfd56af1014ad159828dd9ee2d89c2010b9f4 100644
--- a/src/main/java/net/minecraft/world/level/StructureManager.java
+++ b/src/main/java/net/minecraft/world/level/StructureManager.java
@@ -2,6 +2,7 @@
 package net.minecraft.world.level;
 
 import com.mojang.datafixers.DataFixUtils;
+import it.unimi.dsi.fastutil.objects.ObjectArrayList; // Paper
 import java.util.stream.Stream;
 import javax.annotation.Nullable;
 import net.minecraft.core.BaseBlockPosition;
@@ -12,11 +13,12 @@ import net.minecraft.world.level.chunk.ChunkStatus;
 import net.minecraft.world.level.chunk.IStructureAccess;
 import net.minecraft.world.level.levelgen.GeneratorSettings;
 import net.minecraft.world.level.levelgen.feature.StructureGenerator;
+import net.minecraft.world.level.levelgen.structure.StructurePiece;
 import net.minecraft.world.level.levelgen.structure.StructureStart;
 
 public class StructureManager {
 
-    private final GeneratorAccess a;
+    private final GeneratorAccess a; public GeneratorAccess getLevel() { return a; } // Paper - OBFHELPER
     private final GeneratorSettings b;
 
     public StructureManager(GeneratorAccess generatoraccess, GeneratorSettings generatorsettings) {
@@ -42,6 +44,20 @@ public class StructureManager {
         });
     }
 
+    // Paper start - remove structure streams
+    public java.util.List<StructureStart<?>> getFeatureStarts(SectionPosition sectionPosition, StructureGenerator<?> structureGenerator) {
+        java.util.List<StructureStart<?>> list = new ObjectArrayList<>();
+        for (Long curLong: getLevel().getChunkAt(sectionPosition.a(), sectionPosition.c(), ChunkStatus.STRUCTURE_REFERENCES).b(structureGenerator)) {
+            SectionPosition sectionPosition1 = SectionPosition.a(new ChunkCoordIntPair(curLong), 0);
+            StructureStart<?> structurestart = a(sectionPosition1, structureGenerator, getLevel().getChunkAt(sectionPosition1.a(), sectionPosition1.c(), ChunkStatus.STRUCTURE_STARTS));
+            if (structurestart != null && structurestart.e()) {
+                list.add(structurestart);
+            }
+        }
+        return list;
+    }
+    // Paper end
+
     @Nullable
     public StructureStart<?> a(SectionPosition sectionposition, StructureGenerator<?> structuregenerator, IStructureAccess istructureaccess) {
         return istructureaccess.a(structuregenerator);
@@ -60,13 +76,21 @@ public class StructureManager {
     }
 
     public StructureStart<?> a(BlockPosition blockposition, boolean flag, StructureGenerator<?> structuregenerator) {
-        return (StructureStart) DataFixUtils.orElse(this.a(SectionPosition.a(blockposition), structuregenerator).filter((structurestart) -> {
-            return structurestart.c().b((BaseBlockPosition) blockposition);
-        }).filter((structurestart) -> {
-            return !flag || structurestart.d().stream().anyMatch((structurepiece) -> {
-                return structurepiece.g().b((BaseBlockPosition) blockposition);
-            });
-        }).findFirst(), StructureStart.a);
+        // Paper start - remove structure streams
+        for (StructureStart<?> structurestart : getFeatureStarts(SectionPosition.a(blockposition), structuregenerator)) {
+            if (structurestart.c().b(blockposition)) {
+                if (!flag) {
+                    return structurestart;
+                }
+                for (StructurePiece structurepiece : structurestart.d()) {
+                    if (structurepiece.g().b(blockposition)) {
+                        return structurestart;
+                    }
+                }
+            }
+        }
+        return StructureStart.a;
+        // Paper end
     }
 
     // Spigot start
diff --git a/src/main/java/net/minecraft/world/level/biome/BiomeBase.java b/src/main/java/net/minecraft/world/level/biome/BiomeBase.java
index 7147cdda756ccb3d4f6880802128f68601783883..15096a9c2719b8b4c099f62d0a1c808e56b63a8e 100644
--- a/src/main/java/net/minecraft/world/level/biome/BiomeBase.java
+++ b/src/main/java/net/minecraft/world/level/biome/BiomeBase.java
@@ -39,6 +39,7 @@ import net.minecraft.world.level.levelgen.WorldGenStage;
 import net.minecraft.world.level.levelgen.feature.StructureGenerator;
 import net.minecraft.world.level.levelgen.feature.WorldGenFeatureConfigured;
 import net.minecraft.world.level.levelgen.structure.StructureBoundingBox;
+import net.minecraft.world.level.levelgen.structure.StructureStart;
 import net.minecraft.world.level.levelgen.surfacebuilders.WorldGenSurfaceComposite;
 import net.minecraft.world.level.levelgen.synth.NoiseGenerator3;
 import net.minecraft.world.level.material.Fluid;
@@ -238,9 +239,11 @@ public final class BiomeBase {
                     int l1 = j1 << 4;
 
                     try {
-                        structuremanager.a(SectionPosition.a(blockposition), structuregenerator).forEach((structurestart) -> {
-                            structurestart.a(regionlimitedworldaccess, structuremanager, chunkgenerator, seededrandom, new StructureBoundingBox(k1, l1, k1 + 15, l1 + 15), new ChunkCoordIntPair(i1, j1));
-                        });
+                        // Paper start - remove structure streams
+                        for (StructureStart<?> structureStart : structuremanager.getFeatureStarts(SectionPosition.a(blockposition), structuregenerator)) {
+                            structureStart.a(regionlimitedworldaccess, structuremanager, chunkgenerator, seededrandom, new StructureBoundingBox(k1, l1, k1 + 15, l1 + 15), new ChunkCoordIntPair(i1, j1));
+                        }
+                        // Paper end
                     } catch (Exception exception) {
                         CrashReport crashreport = CrashReport.a(exception, "Feature placement");
 
diff --git a/src/main/java/net/minecraft/world/level/levelgen/ChunkGeneratorAbstract.java b/src/main/java/net/minecraft/world/level/levelgen/ChunkGeneratorAbstract.java
index 700b32322e8d0fbb8ec2824e50a340be16b48f81..369fb0bda22f02e76b901b6eb8990651c53c7577 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/ChunkGeneratorAbstract.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/ChunkGeneratorAbstract.java
@@ -40,6 +40,7 @@ import net.minecraft.world.level.levelgen.feature.structures.WorldGenFeatureDefi
 import net.minecraft.world.level.levelgen.feature.structures.WorldGenFeatureDefinedStructurePoolTemplate;
 import net.minecraft.world.level.levelgen.structure.StructureBoundingBox;
 import net.minecraft.world.level.levelgen.structure.StructurePiece;
+import net.minecraft.world.level.levelgen.structure.StructureStart;
 import net.minecraft.world.level.levelgen.structure.WorldGenFeaturePillagerOutpostPoolPiece;
 import net.minecraft.world.level.levelgen.synth.NoiseGenerator;
 import net.minecraft.world.level.levelgen.synth.NoiseGenerator3;
@@ -455,7 +456,7 @@ public final class ChunkGeneratorAbstract extends ChunkGenerator {
         while (iterator.hasNext()) {
             StructureGenerator<?> structuregenerator = (StructureGenerator) iterator.next();
 
-            structuremanager.a(SectionPosition.a(chunkcoordintpair, 0), structuregenerator).forEach((structurestart) -> {
+            for (StructureStart<?> structurestart : structuremanager.getFeatureStarts(SectionPosition.a(chunkcoordintpair, 0), structuregenerator)) { // Paper - remove structure streams
                 Iterator iterator1 = structurestart.d().iterator();
 
                 while (iterator1.hasNext()) {
@@ -487,7 +488,7 @@ public final class ChunkGeneratorAbstract extends ChunkGenerator {
                     }
                 }
 
-            });
+            } // Paper - remove structure streams
         }
 
         double[][][] adouble = new double[2][this.p + 1][this.o + 1];