SyncableItemStack.java

package openmods.sync;

import com.google.common.io.ByteStreams;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.CompressedStreamTools;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraftforge.common.util.Constants;
import openmods.utils.ByteUtils;
import openmods.utils.ItemUtils;

public class SyncableItemStack extends SyncableObjectBase {

	private static final String TAG_TAG = "tag";
	private static final String TAG_DAMAGE = "Damage";
	private static final String TAG_COUNT = "Count";
	private static final String TAG_ID = "id";
	private ItemStack stack;

	@Override
	public void readFromStream(DataInputStream stream) throws IOException {
		int length = ByteUtils.readVLI(stream);
		if (length > 0) {
			int itemId = stream.readInt();
			byte size = stream.readByte();
			short damage = stream.readShort();

			NBTTagCompound deserialized = new NBTTagCompound();
			deserialized.setInteger(TAG_ID, itemId);
			deserialized.setByte(TAG_COUNT, size);
			deserialized.setShort(TAG_DAMAGE, damage);

			length--;
			if (length > 0) {
				// GZIP stream reads more than needed -> needs bounding if we want to reuse stream
				NBTTagCompound tag = CompressedStreamTools.readCompressed(ByteStreams.limit(stream, length));
				deserialized.setTag(TAG_TAG, tag);
			}

			this.stack = ItemStack.loadItemStackFromNBT(deserialized);
		} else {
			this.stack = null;
		}
	}

	@Override
	public void writeToStream(DataOutputStream stream) throws IOException {
		if (stack != null) {
			NBTTagCompound serialized = new NBTTagCompound();
			stack.writeToNBT(serialized);
			int id = serialized.getInteger(TAG_ID);
			byte size = serialized.getByte(TAG_COUNT);
			short damage = serialized.getShort(TAG_DAMAGE);

			int payloadSize = 1;
			byte[] tagBytes = null;
			if (serialized.hasKey(TAG_TAG)) {
				NBTTagCompound tag = serialized.getCompoundTag(TAG_TAG);
				ByteArrayOutputStream buffer = new ByteArrayOutputStream();
				CompressedStreamTools.writeCompressed(tag, buffer);

				tagBytes = buffer.toByteArray();
				payloadSize += tagBytes.length;
			}

			ByteUtils.writeVLI(stream, payloadSize);
			stream.writeInt(id);
			stream.writeByte(size);
			stream.writeShort(damage);

			if (tagBytes != null) stream.write(tagBytes);
		} else {
			stream.writeByte(0);
		}

	}

	@Override
	public void writeToNBT(NBTTagCompound nbt, String name) {
		if (stack != null) {
			NBTTagCompound serialized = ItemUtils.writeStack(stack);
			nbt.setTag(name, serialized);
		}
	}

	@Override
	public void readFromNBT(NBTTagCompound nbt, String name) {
		if (nbt.hasKey(name, Constants.NBT.TAG_COMPOUND)) {
			NBTTagCompound serialized = nbt.getCompoundTag(name);
			stack = ItemUtils.readStack(serialized);
		} else {
			stack = null;
		}
	}

	public void set(ItemStack stack) {
		this.stack = stack != null? stack.copy() : null;
		markDirty();
	}

	public ItemStack get() {
		return stack;
	}
}