src/game/java/net/minecraft/util/datafix/PackedBitStorage.java

package net.minecraft.util.datafix;

import net.minecraft.util.Mth;
import org.apache.commons.lang3.Validate;

public class PackedBitStorage {
    private static final int BIT_TO_LONG_SHIFT = 6;
    private final long[] data;
    private final int bits;
    private final long mask;
    private final int size;

    public PackedBitStorage(int p_14555_, int p_14556_) {
        this(p_14555_, p_14556_, new long[Mth.roundToward(p_14556_ * p_14555_, 64) / 64]);
    }

    public PackedBitStorage(int p_14558_, int p_14559_, long[] p_14560_) {
        Validate.inclusiveBetween(1L, 32L, (long)p_14558_);
        this.size = p_14559_;
        this.bits = p_14558_;
        this.data = p_14560_;
        this.mask = (1L << p_14558_) - 1L;
        int i = Mth.roundToward(p_14559_ * p_14558_, 64) / 64;
        if (p_14560_.length != i) {
            throw new IllegalArgumentException("Invalid length given for storage, got: " + p_14560_.length + " but expected: " + i);
        }
    }

    public void set(int p_14565_, int p_14566_) {
        Validate.inclusiveBetween(0L, (long)(this.size - 1), (long)p_14565_);
        Validate.inclusiveBetween(0L, this.mask, (long)p_14566_);
        int i = p_14565_ * this.bits;
        int j = i >> 6;
        int k = (p_14565_ + 1) * this.bits - 1 >> 6;
        int l = i ^ j << 6;
        this.data[j] = this.data[j] & ~(this.mask << l) | ((long)p_14566_ & this.mask) << l;
        if (j != k) {
            int i1 = 64 - l;
            int j1 = this.bits - i1;
            this.data[k] = this.data[k] >>> j1 << j1 | ((long)p_14566_ & this.mask) >> i1;
        }
    }

    public int get(int p_14563_) {
        Validate.inclusiveBetween(0L, (long)(this.size - 1), (long)p_14563_);
        int i = p_14563_ * this.bits;
        int j = i >> 6;
        int k = (p_14563_ + 1) * this.bits - 1 >> 6;
        int l = i ^ j << 6;
        if (j == k) {
            return (int)(this.data[j] >>> l & this.mask);
        } else {
            int i1 = 64 - l;
            return (int)((this.data[j] >>> l | this.data[k] << i1) & this.mask);
        }
    }

    public long[] getRaw() {
        return this.data;
    }

    public int getBits() {
        return this.bits;
    }
}