BlueMap/BlueMapCore/src/main/java/de/bluecolored/bluemap/core/world/mca/chunk/ChunkLoader.java

86 lines
3.2 KiB
Java

package de.bluecolored.bluemap.core.world.mca.chunk;
import de.bluecolored.bluemap.core.storage.Compression;
import de.bluecolored.bluemap.core.world.mca.MCAUtil;
import de.bluecolored.bluemap.core.world.mca.MCAWorld;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import org.jetbrains.annotations.Nullable;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.function.BiFunction;
public class ChunkLoader {
private final MCAWorld world;
public ChunkLoader(MCAWorld world) {
this.world = world;
}
// sorted list of chunk-versions, loaders at the start of the list are preferred over loaders at the end
private static final List<ChunkVersionLoader<?>> CHUNK_VERSION_LOADERS = List.of(
new ChunkVersionLoader<>(Chunk_1_18.Data.class, Chunk_1_18::new, 2844),
new ChunkVersionLoader<>(Chunk_1_16.Data.class, Chunk_1_16::new, 2500),
new ChunkVersionLoader<>(Chunk_1_15.Data.class, Chunk_1_15::new, 2200),
new ChunkVersionLoader<>(Chunk_1_13.Data.class, Chunk_1_13::new, 0)
);
private ChunkVersionLoader<?> lastUsedLoader = CHUNK_VERSION_LOADERS.get(0);
public MCAChunk load(byte[] data, int offset, int length, Compression compression) throws IOException {
InputStream in = new ByteArrayInputStream(data, offset, length);
in.mark(-1);
// try last used version
ChunkVersionLoader<?> usedLoader = lastUsedLoader;
MCAChunk chunk;
try (InputStream decompressedIn = new BufferedInputStream(compression.decompress(in))) {
chunk = usedLoader.load(world, decompressedIn);
}
// check version and reload chunk if the wrong loader has been used and a better one has been found
ChunkVersionLoader<?> actualLoader = findBestLoaderForVersion(chunk.getDataVersion());
if (actualLoader != null && usedLoader != actualLoader) {
in.reset(); // reset read position
try (InputStream decompressedIn = new BufferedInputStream(compression.decompress(in))) {
chunk = actualLoader.load(world, decompressedIn);
}
lastUsedLoader = actualLoader;
}
return chunk;
}
private @Nullable ChunkVersionLoader<?> findBestLoaderForVersion(int version) {
for (ChunkVersionLoader<?> loader : CHUNK_VERSION_LOADERS) {
if (loader.mightSupport(version)) return loader;
}
return null;
}
@RequiredArgsConstructor
@Getter
private static class ChunkVersionLoader<D extends MCAChunk.Data> {
private final Class<D> dataType;
private final BiFunction<MCAWorld, D, MCAChunk> constructor;
private final int dataVersion;
public MCAChunk load(MCAWorld world, InputStream in) throws IOException {
D data = MCAUtil.BLUENBT.read(in, dataType);
return mightSupport(data.getDataVersion()) ? constructor.apply(world, data) : new MCAChunk(world, data) {};
}
public boolean mightSupport(int dataVersion) {
return dataVersion >= this.dataVersion;
}
}
}