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; import java.util.zip.GZIPInputStream; /** *

This class reads NBT, or * Named Binary Tag streams, and produces an object graph of * subclasses of the Tag object.

* *

The NBT format was created by Markus Persson, and the specification may * be found at * http://www.minecraft.net/docs/NBT.txt.

* @author Graham Edgecombe * */ public final class NBTInputStream implements Closeable { /** * The data input stream. */ private final DataInputStream is; /** * Creates a new 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(new GZIPInputStream(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 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 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); default: throw new IOException("Invalid tag type: " + type + "."); } } @Override public void close() throws IOException { is.close(); } }