/*
* 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 net.aufdemrand.denizen.nms.util.jnbt;
import net.aufdemrand.denizen.nms.NMSHandler;
import java.io.Closeable;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* This class reads <strong>NBT</strong>, or <strong>Named Binary Tag</strong>
* streams, and produces an object graph of subclasses of the {@code Tag}
* object.
* <p/>
* <p>The NBT format was created by Markus Persson, and the specification may be
* found at <a href="http://www.minecraft.net/docs/NBT.txt">
* http://www.minecraft.net/docs/NBT.txt</a>.</p>
*/
public final class NBTInputStream implements Closeable {
private final DataInputStream is;
/**
* Creates a new {@code NBTInputStream}, which will source its data
* from the specified input stream.
*
* @param is the input stream
* @throws IOException if an I/O error occurs
*/
public NBTInputStream(InputStream is) throws IOException {
this.is = new DataInputStream(is);
}
/**
* Reads an NBT tag from the stream.
*
* @return The tag that was read.
* @throws IOException if an I/O error occurs.
*/
public NamedTag readNamedTag() throws IOException {
return readNamedTag(0);
}
/**
* Reads an NBT from the stream.
*
* @param depth the depth of this tag
* @return The tag that was read.
* @throws IOException if an I/O error occurs.
*/
private NamedTag readNamedTag(int depth) throws IOException {
int type = is.readByte() & 0xFF;
String name;
if (type != NBTConstants.TYPE_END) {
int nameLength = is.readShort() & 0xFFFF;
byte[] nameBytes = new byte[nameLength];
is.readFully(nameBytes);
name = new String(nameBytes, NBTConstants.CHARSET);
}
else {
name = "";
}
return new NamedTag(name, readTagPayload(type, depth));
}
/**
* Reads the payload of a tag given the type.
*
* @param type the type
* @param depth the depth
* @return the tag
* @throws IOException if an I/O error occurs.
*/
private Tag readTagPayload(int type, int depth) throws IOException {
switch (type) {
case NBTConstants.TYPE_END:
if (depth == 0) {
throw new IOException(
"TAG_End found without a TAG_Compound/TAG_List tag preceding it.");
}
else {
return new EndTag();
}
case NBTConstants.TYPE_BYTE:
return new ByteTag(is.readByte());
case NBTConstants.TYPE_SHORT:
return new ShortTag(is.readShort());
case NBTConstants.TYPE_INT:
return new IntTag(is.readInt());
case NBTConstants.TYPE_LONG:
return new LongTag(is.readLong());
case NBTConstants.TYPE_FLOAT:
return new FloatTag(is.readFloat());
case NBTConstants.TYPE_DOUBLE:
return new DoubleTag(is.readDouble());
case NBTConstants.TYPE_BYTE_ARRAY:
int length = is.readInt();
byte[] bytes = new byte[length];
is.readFully(bytes);
return new ByteArrayTag(bytes);
case NBTConstants.TYPE_STRING:
length = is.readShort();
bytes = new byte[length];
is.readFully(bytes);
return new StringTag(new String(bytes, NBTConstants.CHARSET));
case NBTConstants.TYPE_LIST:
int childType = is.readByte();
length = is.readInt();
List<Tag> tagList = new ArrayList<Tag>();
for (int i = 0; i < length; ++i) {
Tag tag = readTagPayload(childType, depth + 1);
if (tag instanceof EndTag) {
throw new IOException("TAG_End not permitted in a list.");
}
tagList.add(tag);
}
return new ListTag(NBTUtils.getTypeClass(childType), tagList);
case NBTConstants.TYPE_COMPOUND:
Map<String, Tag> tagMap = new HashMap<String, Tag>();
while (true) {
NamedTag namedTag = readNamedTag(depth + 1);
Tag tag = namedTag.getTag();
if (tag instanceof EndTag) {
break;
}
else {
tagMap.put(namedTag.getName(), tag);
}
}
return NMSHandler.getInstance().createCompoundTag(tagMap);
case NBTConstants.TYPE_INT_ARRAY:
length = is.readInt();
int[] data = new int[length];
for (int i = 0; i < length; i++) {
data[i] = is.readInt();
}
return new IntArrayTag(data);
default:
throw new IOException("Invalid tag type: " + type + ".");
}
}
@Override
public void close() throws IOException {
is.close();
}
}