Code/net/minecraft/world/level/entity/EntitySectionStorage.java

package net.minecraft.world.level.entity;

import it.unimi.dsi.fastutil.longs.Long2ObjectFunction;
import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
import it.unimi.dsi.fastutil.longs.LongAVLTreeSet;
import it.unimi.dsi.fastutil.longs.LongIterator;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
import it.unimi.dsi.fastutil.longs.LongSet;
import it.unimi.dsi.fastutil.longs.LongSortedSet;
import java.util.Objects;
import java.util.Spliterators;
import java.util.PrimitiveIterator.OfLong;
import java.util.stream.LongStream;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import javax.annotation.Nullable;
import net.minecraft.core.SectionPos;
import net.minecraft.util.AbortableIterationConsumer;
import net.minecraft.util.VisibleForDebug;
import net.minecraft.world.level.ChunkPos;
import net.minecraft.world.phys.AABB;

public class EntitySectionStorage<T extends EntityAccess> {
    public static final int CHONKY_ENTITY_SEARCH_GRACE = 2;
    public static final int MAX_NON_CHONKY_ENTITY_SIZE = 4;
    private final Class<T> entityClass;
    private final Long2ObjectFunction<Visibility> intialSectionVisibility;
    private final Long2ObjectMap<EntitySection<T>> sections = new Long2ObjectOpenHashMap<>();
    private final LongSortedSet sectionIds = new LongAVLTreeSet();

    public EntitySectionStorage(Class<T> p_156855_, Long2ObjectFunction<Visibility> p_156856_) {
        this.entityClass = p_156855_;
        this.intialSectionVisibility = p_156856_;
    }

    public void forEachAccessibleNonEmptySection(AABB p_188363_, AbortableIterationConsumer<EntitySection<T>> p_261588_) {
        int i = SectionPos.posToSectionCoord(p_188363_.minX - 2.0);
        int j = SectionPos.posToSectionCoord(p_188363_.minY - 4.0);
        int k = SectionPos.posToSectionCoord(p_188363_.minZ - 2.0);
        int l = SectionPos.posToSectionCoord(p_188363_.maxX + 2.0);
        int i1 = SectionPos.posToSectionCoord(p_188363_.maxY + 0.0);
        int j1 = SectionPos.posToSectionCoord(p_188363_.maxZ + 2.0);

        for (int k1 = i; k1 <= l; k1++) {
            long l1 = SectionPos.asLong(k1, 0, 0);
            long i2 = SectionPos.asLong(k1, -1, -1);
            LongIterator longiterator = this.sectionIds.subSet(l1, i2 + 1L).iterator();

            while (longiterator.hasNext()) {
                long j2 = longiterator.nextLong();
                int k2 = SectionPos.y(j2);
                int l2 = SectionPos.z(j2);
                if (k2 >= j && k2 <= i1 && l2 >= k && l2 <= j1) {
                    EntitySection<T> entitysection = this.sections.get(j2);
                    if (entitysection != null
                        && !entitysection.isEmpty()
                        && entitysection.getStatus().isAccessible()
                        && p_261588_.accept(entitysection).shouldAbort()) {
                        return;
                    }
                }
            }
        }
    }

    public LongStream getExistingSectionPositionsInChunk(long p_156862_) {
        int i = ChunkPos.getX(p_156862_);
        int j = ChunkPos.getZ(p_156862_);
        LongSortedSet longsortedset = this.getChunkSections(i, j);
        if (longsortedset.isEmpty()) {
            return LongStream.empty();
        } else {
            OfLong oflong = longsortedset.iterator();
            return StreamSupport.longStream(Spliterators.spliteratorUnknownSize(oflong, 1301), false);
        }
    }

    private LongSortedSet getChunkSections(int p_156859_, int p_156860_) {
        long i = SectionPos.asLong(p_156859_, 0, p_156860_);
        long j = SectionPos.asLong(p_156859_, -1, p_156860_);
        return this.sectionIds.subSet(i, j + 1L);
    }

    public Stream<EntitySection<T>> getExistingSectionsInChunk(long p_156889_) {
        return this.getExistingSectionPositionsInChunk(p_156889_).mapToObj(this.sections::get).filter(Objects::nonNull);
    }

    private static long getChunkKeyFromSectionKey(long p_156900_) {
        return ChunkPos.asLong(SectionPos.x(p_156900_), SectionPos.z(p_156900_));
    }

    public EntitySection<T> getOrCreateSection(long p_156894_) {
        return this.sections.computeIfAbsent(p_156894_, this::createSection);
    }

    @Nullable
    public EntitySection<T> getSection(long p_156896_) {
        return this.sections.get(p_156896_);
    }

    private EntitySection<T> createSection(long p_156902_) {
        long i = getChunkKeyFromSectionKey(p_156902_);
        Visibility visibility = this.intialSectionVisibility.get(i);
        this.sectionIds.add(p_156902_);
        return new EntitySection<>(this.entityClass, visibility);
    }

    public LongSet getAllChunksWithExistingSections() {
        LongSet longset = new LongOpenHashSet();
        this.sections.keySet().forEach((long p_156886_) -> longset.add(getChunkKeyFromSectionKey(p_156886_)));
        return longset;
    }

    public void getEntities(AABB p_261820_, AbortableIterationConsumer<T> p_261992_) {
        this.forEachAccessibleNonEmptySection(p_261820_, p_261459_ -> p_261459_.getEntities(p_261820_, p_261992_));
    }

    public <U extends T> void getEntities(EntityTypeTest<T, U> p_261630_, AABB p_261843_, AbortableIterationConsumer<U> p_261742_) {
        this.forEachAccessibleNonEmptySection(p_261843_, p_261463_ -> p_261463_.getEntities(p_261630_, p_261843_, p_261742_));
    }

    public void remove(long p_156898_) {
        this.sections.remove(p_156898_);
        this.sectionIds.remove(p_156898_);
    }

    @VisibleForDebug
    public int count() {
        return this.sectionIds.size();
    }
}