package org.jnbt;
/*
* JNBT License
*
* Copyright (c) 2010 Graham Edgecombe
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the JNBT team nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
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;
/**
* <p>This class reads <strong>NBT</strong>, or
* <strong>Named Binary Tag</strong> streams, and produces an object graph of
* subclasses of the <code>Tag</code> 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>
* @author Graham Edgecombe
*
*/
public final class NBTInputStream implements Closeable {
/**
* The data input stream.
*/
private final DataInputStream is;
/**
* Creates a new <code>NBTInputStream</code>, 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(new GZIPInputStream(is));
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 Tag readTag() throws IOException {
return readTag(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 Tag readTag(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 readTagPayload(type, name, depth);
}
/**
* Reads the payload of a tag, given the name and type.
* @param type The type.
* @param name The name.
* @param depth The depth.
* @return The tag.
* @throws IOException if an I/O error occurs.
*/
private Tag readTagPayload(int type, String name, 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(name, is.readByte());
case NBTConstants.TYPE_SHORT:
return new ShortTag(name, is.readShort());
case NBTConstants.TYPE_INT:
return new IntTag(name, is.readInt());
case NBTConstants.TYPE_LONG:
return new LongTag(name, is.readLong());
case NBTConstants.TYPE_FLOAT:
return new FloatTag(name, is.readFloat());
case NBTConstants.TYPE_DOUBLE:
return new DoubleTag(name, is.readDouble());
case NBTConstants.TYPE_BYTE_ARRAY:
int length = is.readInt();
byte[] bytes = new byte[length];
is.readFully(bytes);
return new ByteArrayTag(name, bytes);
case NBTConstants.TYPE_STRING:
length = is.readShort();
bytes = new byte[length];
is.readFully(bytes);
return new StringTag(name, new String(bytes, NBTConstants.CHARSET));
case NBTConstants.TYPE_LIST:
int childType = is.readByte();
length = is.readInt();
List<Tag> tagList = new ArrayList<>();
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(name, NBTUtils.getTypeClass(childType), tagList);
case NBTConstants.TYPE_COMPOUND:
Map<String, Tag> tagMap = new HashMap<>();
while (true) {
Tag tag = readTag(depth + 1);
if (tag instanceof EndTag) {
break;
} else {
tagMap.put(tag.getName(), tag);
}
}
return new CompoundTag(name, tagMap);
case NBTConstants.TYPE_INT_ARRAY:
length = is.readInt();
int[] values = new int[length];
for (int i = 0; i < length; i++) {
values[i] = is.readInt();
}
return new IntArrayTag(name, values);
default:
throw new IOException("Invalid tag type: " + type + ".");
}
}
public void close() throws IOException {
is.close();
}
}