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Original DnsSd TxtRecord file
Change-Id: I4aa308a3b417d6bdce50567fb66c7119b048140a
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‎NOTICE

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@@ -53,6 +53,17 @@ Media Codecs
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These files are Copyright 1998 - 2009 PacketVideo, but released under
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the Apache2 License.
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=========================================================================
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== NOTICE file corresponding to the section 4 d of ==
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== the Apache License, Version 2.0, ==
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== in this case for the mDnsResponder code. ==
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=========================================================================
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mDnsResponder TXTRecord
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This file is Copyright 2004 Apple Computer, Inc. but released under
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the Apache2 License.
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=========================================================================
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== NOTICE file corresponding to the section 4 d of ==
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== the Apache License, Version 2.0, ==

‎core/java/android/net/nsd/DnsSdTxtRecord.java

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/* -*- Mode: Java; tab-width: 4 -*-
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*
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* Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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To do:
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- implement remove()
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- fix set() to replace existing values
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*/
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package com.apple.dnssd;
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/**
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Object used to construct and parse DNS-SD format TXT records.
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For more info see <a href="http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt">DNS-Based Service Discovery</a>, section 6.
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*/
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public class TXTRecord
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{
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/*
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DNS-SD specifies that a TXT record corresponding to an SRV record consist of
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a packed array of bytes, each preceded by a length byte. Each string
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is an attribute-value pair.
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The TXTRecord object stores the entire TXT data as a single byte array, traversing it
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as need be to implement its various methods.
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*/
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static final protected byte kAttrSep = '=';
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protected byte[] fBytes;
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/** Constructs a new, empty TXT record. */
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public TXTRecord()
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{ fBytes = new byte[0]; }
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/** Constructs a new TXT record from a byte array in the standard format. */
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public TXTRecord( byte[] initBytes)
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{ fBytes = (byte[]) initBytes.clone(); }
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/** Set a key/value pair in the TXT record. Setting an existing key will replace its value.<P>
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@param key
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The key name. Must be ASCII, with no '=' characters.
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<P>
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@param value
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Value to be encoded into bytes using the default platform character set.
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*/
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public void set( String key, String value)
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{
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byte[] valBytes = (value != null) ? value.getBytes() : null;
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this.set( key, valBytes);
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}
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/** Set a key/value pair in the TXT record. Setting an existing key will replace its value.<P>
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@param key
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The key name. Must be ASCII, with no '=' characters.
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<P>
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@param value
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Binary representation of the value.
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*/
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public void set( String key, byte[] value)
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{
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byte[] keyBytes;
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int valLen = (value != null) ? value.length : 0;
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try {
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keyBytes = key.getBytes( "US-ASCII");
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}
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catch ( java.io.UnsupportedEncodingException uee) {
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throw new IllegalArgumentException();
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}
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for ( int i=0; i < keyBytes.length; i++)
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if ( keyBytes[i] == '=')
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throw new IllegalArgumentException();
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if ( keyBytes.length + valLen >= 255)
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throw new ArrayIndexOutOfBoundsException();
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int prevLoc = this.remove( key);
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if ( prevLoc == -1)
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prevLoc = this.size();
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this.insert( keyBytes, value, prevLoc);
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}
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protected void insert( byte[] keyBytes, byte[] value, int index)
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// Insert a key-value pair at index
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{
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byte[] oldBytes = fBytes;
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int valLen = (value != null) ? value.length : 0;
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int insertion = 0;
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int newLen, avLen;
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// locate the insertion point
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for ( int i=0; i < index && insertion < fBytes.length; i++)
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insertion += (0xFF & (fBytes[ insertion] + 1));
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avLen = keyBytes.length + valLen + (value != null ? 1 : 0);
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newLen = avLen + oldBytes.length + 1;
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fBytes = new byte[ newLen];
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System.arraycopy( oldBytes, 0, fBytes, 0, insertion);
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int secondHalfLen = oldBytes.length - insertion;
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System.arraycopy( oldBytes, insertion, fBytes, newLen - secondHalfLen, secondHalfLen);
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fBytes[ insertion] = ( byte) avLen;
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System.arraycopy( keyBytes, 0, fBytes, insertion + 1, keyBytes.length);
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if ( value != null)
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{
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fBytes[ insertion + 1 + keyBytes.length] = kAttrSep;
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System.arraycopy( value, 0, fBytes, insertion + keyBytes.length + 2, valLen);
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}
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}
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/** Remove a key/value pair from the TXT record. Returns index it was at, or -1 if not found. */
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public int remove( String key)
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{
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int avStart = 0;
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for ( int i=0; avStart < fBytes.length; i++)
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{
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int avLen = fBytes[ avStart];
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if ( key.length() <= avLen &&
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( key.length() == avLen || fBytes[ avStart + key.length() + 1] == kAttrSep))
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{
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String s = new String( fBytes, avStart + 1, key.length());
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if ( 0 == key.compareToIgnoreCase( s))
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{
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byte[] oldBytes = fBytes;
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fBytes = new byte[ oldBytes.length - avLen - 1];
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System.arraycopy( oldBytes, 0, fBytes, 0, avStart);
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System.arraycopy( oldBytes, avStart + avLen + 1, fBytes, avStart, oldBytes.length - avStart - avLen - 1);
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return i;
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}
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}
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avStart += (0xFF & (avLen + 1));
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}
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return -1;
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}
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/** Return the number of keys in the TXT record. */
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public int size()
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{
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int i, avStart;
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for ( i=0, avStart=0; avStart < fBytes.length; i++)
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avStart += (0xFF & (fBytes[ avStart] + 1));
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return i;
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}
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/** Return true if key is present in the TXT record, false if not. */
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public boolean contains( String key)
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{
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String s = null;
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for ( int i=0; null != ( s = this.getKey( i)); i++)
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if ( 0 == key.compareToIgnoreCase( s))
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return true;
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return false;
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}
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/** Return a key in the TXT record by zero-based index. Returns null if index exceeds the total number of keys. */
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public String getKey( int index)
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{
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int avStart = 0;
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for ( int i=0; i < index && avStart < fBytes.length; i++)
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avStart += fBytes[ avStart] + 1;
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if ( avStart < fBytes.length)
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{
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int avLen = fBytes[ avStart];
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int aLen = 0;
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for ( aLen=0; aLen < avLen; aLen++)
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if ( fBytes[ avStart + aLen + 1] == kAttrSep)
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break;
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return new String( fBytes, avStart + 1, aLen);
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}
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return null;
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}
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/**
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Look up a key in the TXT record by zero-based index and return its value. <P>
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Returns null if index exceeds the total number of keys.
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Returns null if the key is present with no value.
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*/
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public byte[] getValue( int index)
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{
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int avStart = 0;
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byte[] value = null;
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for ( int i=0; i < index && avStart < fBytes.length; i++)
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avStart += fBytes[ avStart] + 1;
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if ( avStart < fBytes.length)
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{
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int avLen = fBytes[ avStart];
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int aLen = 0;
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for ( aLen=0; aLen < avLen; aLen++)
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{
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if ( fBytes[ avStart + aLen + 1] == kAttrSep)
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{
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value = new byte[ avLen - aLen - 1];
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System.arraycopy( fBytes, avStart + aLen + 2, value, 0, avLen - aLen - 1);
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break;
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}
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}
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}
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return value;
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}
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/** Converts the result of getValue() to a string in the platform default character set. */
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public String getValueAsString( int index)
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{
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byte[] value = this.getValue( index);
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return value != null ? new String( value) : null;
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}
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/** Get the value associated with a key. Will be null if the key is not defined.
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Array will have length 0 if the key is defined with an = but no value.<P>
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@param forKey
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The left-hand side of the key-value pair.
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<P>
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@return The binary representation of the value.
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*/
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public byte[] getValue( String forKey)
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{
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String s = null;
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int i;
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for ( i=0; null != ( s = this.getKey( i)); i++)
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if ( 0 == forKey.compareToIgnoreCase( s))
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return this.getValue( i);
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return null;
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}
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/** Converts the result of getValue() to a string in the platform default character set.<P>
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@param forKey
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The left-hand side of the key-value pair.
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<P>
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@return The value represented in the default platform character set.
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*/
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public String getValueAsString( String forKey)
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{
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byte[] val = this.getValue( forKey);
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return val != null ? new String( val) : null;
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}
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/** Return the contents of the TXT record as raw bytes. */
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public byte[] getRawBytes() { return (byte[]) fBytes.clone(); }
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/** Return a string representation of the object. */
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public String toString()
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{
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String a, result = null;
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for ( int i=0; null != ( a = this.getKey( i)); i++)
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{
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String av = String.valueOf( i) + "={" + a;
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String val = this.getValueAsString( i);
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if ( val != null)
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av += "=" + val + "}";
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else
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av += "}";
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if ( result == null)
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result = av;
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else
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result = result + ", " + av;
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}
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return result != null ? result : "";
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}
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}

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