/*
* WorldEdit, a Minecraft world manipulation toolkit
* Copyright (C) sk89q <http://www.sk89q.com>
* Copyright (C) WorldEdit team and contributors
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.sk89q.worldedit.world.storage;
import com.sk89q.jnbt.CompoundTag;
import com.sk89q.jnbt.NBTInputStream;
import com.sk89q.jnbt.Tag;
import com.sk89q.worldedit.*;
import com.sk89q.worldedit.world.DataException;
import com.sk89q.worldedit.world.World;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import java.util.zip.GZIPInputStream;
/**
* Represents chunk stores that use Alpha's file format for storing chunks.
* The code to resolve the filename is already implemented in this class
* and an inheriting class merely needs to implement getInputStream().
*/
public abstract class LegacyChunkStore extends ChunkStore {
/**
* Get the filename of a chunk.
*
* @param position chunk position
* @param separator folder separator character
* @return pathname
*/
public static String getFilename(Vector2D position, String separator) {
int x = position.getBlockX();
int z = position.getBlockZ();
String folder1 = Integer.toString(divisorMod(x, 64), 36);
String folder2 = Integer.toString(divisorMod(z, 64), 36);
String filename = "c." + Integer.toString(x, 36)
+ "." + Integer.toString(z, 36) + ".dat";
return folder1 + separator + folder2 + separator + filename;
}
/**
* Get the filename of a chunk, using the system's default path
* separator.
*
* @param position chunk position
* @return pathname
*/
public static String getFilename(Vector2D position) {
return getFilename(position, File.separator);
}
@Override
public CompoundTag getChunkTag(Vector2D position, World world) throws DataException, IOException {
int x = position.getBlockX();
int z = position.getBlockZ();
String folder1 = Integer.toString(divisorMod(x, 64), 36);
String folder2 = Integer.toString(divisorMod(z, 64), 36);
String filename = "c." + Integer.toString(x, 36)
+ "." + Integer.toString(z, 36) + ".dat";
InputStream stream = getInputStream(folder1, folder2, filename);
NBTInputStream nbt = new NBTInputStream(
new GZIPInputStream(stream));
Tag tag;
try {
tag = nbt.readNamedTag().getTag();
if (!(tag instanceof CompoundTag)) {
throw new ChunkStoreException("CompoundTag expected for chunk; got "
+ tag.getClass().getName());
}
Map<String, Tag> children = ((CompoundTag) tag).getValue();
CompoundTag rootTag = null;
// Find Level tag
for (Map.Entry<String, Tag> entry : children.entrySet()) {
if (entry.getKey().equals("Level")) {
if (entry.getValue() instanceof CompoundTag) {
rootTag = (CompoundTag) entry.getValue();
break;
} else {
throw new ChunkStoreException("CompoundTag expected for 'Level'; got "
+ entry.getValue().getClass().getName());
}
}
}
if (rootTag == null) {
throw new ChunkStoreException("Missing root 'Level' tag");
}
return rootTag;
} finally {
nbt.close();
}
}
private static int divisorMod(int a, int n) {
return (int) (a - n * Math.floor(Math.floor(a) / (double) n));
}
/**
* Get the input stream for a chunk file.
*
* @param f1 the first part of the path
* @param f2 the second part of the path
* @param name the name
* @return an input stream
* @throws IOException
*/
protected abstract InputStream getInputStream(String f1, String f2, String name) throws IOException, DataException;
}