Code/net/minecraft/world/level/lighting/DynamicGraphMinFixedPoint.java

package net.minecraft.world.level.lighting;

import it.unimi.dsi.fastutil.longs.Long2ByteMap;
import it.unimi.dsi.fastutil.longs.Long2ByteOpenHashMap;
import it.unimi.dsi.fastutil.longs.LongArrayList;
import it.unimi.dsi.fastutil.longs.LongList;
import java.util.function.LongPredicate;
import net.minecraft.util.Mth;

public abstract class DynamicGraphMinFixedPoint {
    public static final long SOURCE = Long.MAX_VALUE;
    private static final int NO_COMPUTED_LEVEL = 255;
    protected final int levelCount;
    private final LeveledPriorityQueue priorityQueue;
    private final Long2ByteMap computedLevels;
    private volatile boolean hasWork;

    protected DynamicGraphMinFixedPoint(int p_75543_, int p_75544_, final int p_75545_) {
        if (p_75543_ >= 254) {
            throw new IllegalArgumentException("Level count must be < 254.");
        } else {
            this.levelCount = p_75543_;
            this.priorityQueue = new LeveledPriorityQueue(p_75543_, p_75544_);
            this.computedLevels = new Long2ByteOpenHashMap(p_75545_, 0.5F) {
                @Override
                protected void rehash(int p_75611_) {
                    if (p_75611_ > p_75545_) {
                        super.rehash(p_75611_);
                    }
                }
            };
            this.computedLevels.defaultReturnValue((byte)-1);
        }
    }

    protected void removeFromQueue(long p_75601_) {
        int i = this.computedLevels.remove(p_75601_) & 255;
        if (i != 255) {
            int j = this.getLevel(p_75601_);
            int k = this.calculatePriority(j, i);
            this.priorityQueue.dequeue(p_75601_, k, this.levelCount);
            this.hasWork = !this.priorityQueue.isEmpty();
        }
    }

    public void removeIf(LongPredicate p_75582_) {
        LongList longlist = new LongArrayList();
        this.computedLevels.keySet().forEach((long p_75586_) -> {
            if (p_75582_.test(p_75586_)) {
                longlist.add(p_75586_);
            }
        });
        longlist.forEach((java.util.function.LongConsumer)this::removeFromQueue);
    }

    private int calculatePriority(int p_278256_, int p_278328_) {
        return Math.min(Math.min(p_278256_, p_278328_), this.levelCount - 1);
    }

    protected void checkNode(long p_75602_) {
        this.checkEdge(p_75602_, p_75602_, this.levelCount - 1, false);
    }

    protected void checkEdge(long p_75577_, long p_75578_, int p_75579_, boolean p_75580_) {
        this.checkEdge(p_75577_, p_75578_, p_75579_, this.getLevel(p_75578_), this.computedLevels.get(p_75578_) & 255, p_75580_);
        this.hasWork = !this.priorityQueue.isEmpty();
    }

    private void checkEdge(long p_75570_, long p_75571_, int p_75572_, int p_75573_, int p_75574_, boolean p_75575_) {
        if (!this.isSource(p_75571_)) {
            p_75572_ = Mth.clamp(p_75572_, 0, this.levelCount - 1);
            p_75573_ = Mth.clamp(p_75573_, 0, this.levelCount - 1);
            boolean flag = p_75574_ == 255;
            if (flag) {
                p_75574_ = p_75573_;
            }

            int i;
            if (p_75575_) {
                i = Math.min(p_75574_, p_75572_);
            } else {
                i = Mth.clamp(this.getComputedLevel(p_75571_, p_75570_, p_75572_), 0, this.levelCount - 1);
            }

            int j = this.calculatePriority(p_75573_, p_75574_);
            if (p_75573_ != i) {
                int k = this.calculatePriority(p_75573_, i);
                if (j != k && !flag) {
                    this.priorityQueue.dequeue(p_75571_, j, k);
                }

                this.priorityQueue.enqueue(p_75571_, k);
                this.computedLevels.put(p_75571_, (byte)i);
            } else if (!flag) {
                this.priorityQueue.dequeue(p_75571_, j, this.levelCount);
                this.computedLevels.remove(p_75571_);
            }
        }
    }

    protected final void checkNeighbor(long p_75594_, long p_75595_, int p_75596_, boolean p_75597_) {
        int i = this.computedLevels.get(p_75595_) & 255;
        int j = Mth.clamp(this.computeLevelFromNeighbor(p_75594_, p_75595_, p_75596_), 0, this.levelCount - 1);
        if (p_75597_) {
            this.checkEdge(p_75594_, p_75595_, j, this.getLevel(p_75595_), i, p_75597_);
        } else {
            boolean flag = i == 255;
            int k;
            if (flag) {
                k = Mth.clamp(this.getLevel(p_75595_), 0, this.levelCount - 1);
            } else {
                k = i;
            }

            if (j == k) {
                this.checkEdge(p_75594_, p_75595_, this.levelCount - 1, flag ? k : this.getLevel(p_75595_), i, p_75597_);
            }
        }
    }

    protected final boolean hasWork() {
        return this.hasWork;
    }

    protected final int runUpdates(int p_75589_) {
        if (this.priorityQueue.isEmpty()) {
            return p_75589_;
        } else {
            while (!this.priorityQueue.isEmpty() && p_75589_ > 0) {
                p_75589_--;
                long i = this.priorityQueue.removeFirstLong();
                int j = Mth.clamp(this.getLevel(i), 0, this.levelCount - 1);
                int k = this.computedLevels.remove(i) & 255;
                if (k < j) {
                    this.setLevel(i, k);
                    this.checkNeighborsAfterUpdate(i, k, true);
                } else if (k > j) {
                    this.setLevel(i, this.levelCount - 1);
                    if (k != this.levelCount - 1) {
                        this.priorityQueue.enqueue(i, this.calculatePriority(this.levelCount - 1, k));
                        this.computedLevels.put(i, (byte)k);
                    }

                    this.checkNeighborsAfterUpdate(i, j, false);
                }
            }

            this.hasWork = !this.priorityQueue.isEmpty();
            return p_75589_;
        }
    }

    public int getQueueSize() {
        return this.computedLevels.size();
    }

    protected boolean isSource(long p_75551_) {
        return p_75551_ == Long.MAX_VALUE;
    }

    protected abstract int getComputedLevel(long p_75566_, long p_75567_, int p_75568_);

    protected abstract void checkNeighborsAfterUpdate(long p_75563_, int p_75564_, boolean p_75565_);

    protected abstract int getLevel(long p_75599_);

    protected abstract void setLevel(long p_75552_, int p_75553_);

    protected abstract int computeLevelFromNeighbor(long p_75590_, long p_75591_, int p_75592_);
}