// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)package org.xbill.DNS;/** * DNS Name Compression object. * @see Message * @see Name * * @author Brian Wellington */public class Compression {private static class Entry {	Name name;	int pos;	Entry next;}private static final int TABLE_SIZE = 17;private Entry [] table;private boolean verbose = Options.check("verbosecompression");/** * Creates a new Compression object. */publicCompression() {	table = new Entry[TABLE_SIZE];}/** * Adds a compression entry mapping a name to a position in a message. * @param pos The position at which the name is added. * @param name The name being added to the message. */public voidadd(int pos, Name name) {	int row = (name.hashCode() & 0x7FFFFFFF) % TABLE_SIZE;	Entry entry = new Entry();	entry.name = name;	entry.pos = pos;	entry.next = table[row];	table[row] = entry;	if (verbose)		System.err.println("Adding " + name + " at " + pos);}/** * Retrieves the position of the given name, if it has been previously * included in the message. * @param name The name to find in the compression table. * @return The position of the name, or -1 if not found. */public intget(Name name) {	int row = (name.hashCode() & 0x7FFFFFFF) % TABLE_SIZE;	int pos = -1;	for (Entry entry = table[row]; entry != null; entry = entry.next) {		if (entry.name.equals(name))			pos = entry.pos;	}	if (verbose)		System.err.println("Looking for " + name + ", found " + pos);	return pos;}}