Original DnsSd TxtRecord file

Change-Id: I4aa308a3b417d6bdce50567fb66c7119b048140a

NOTICE

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

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

@@ -0,0 +1,289 @@
+/* -*- Mode: Java; tab-width: 4 -*-
+ *
+ * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+
+	To do:
+	- implement remove()
+	- fix set() to replace existing values
+ */
+
+
+package	com.apple.dnssd;
+
+
+/**	
+	Object used to construct and parse DNS-SD format TXT records.
+	For more info see <a href="http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt">DNS-Based Service Discovery</a>, section 6. 
+*/
+
+public class	TXTRecord
+{
+	/* 
+	DNS-SD specifies that a TXT record corresponding to an SRV record consist of
+	a packed array of bytes, each preceded by a length byte. Each string
+	is an attribute-value pair. 
+	
+	The TXTRecord object stores the entire TXT data as a single byte array, traversing it
+	as need be to implement its various methods.
+	*/
+
+	static final protected byte		kAttrSep = '=';
+
+	protected byte[]		fBytes;
+
+	/** Constructs a new, empty TXT record. */
+	public		TXTRecord() 
+	{ fBytes = new byte[0]; }
+
+	/** Constructs a new TXT record from a byte array in the standard format. */
+	public		TXTRecord( byte[] initBytes) 
+	{ fBytes = (byte[]) initBytes.clone(); }
+
+	/** Set a key/value pair in the TXT record. Setting an existing key will replace its value.<P>
+		@param	key
+					The key name. Must be ASCII, with no '=' characters.
+		<P>
+		@param	value
+					Value to be encoded into bytes using the default platform character set.
+	*/
+	public void	set( String key, String value)
+	{
+		byte[]	valBytes = (value != null) ? value.getBytes() : null;
+		this.set( key, valBytes);
+	}
+
+	/** Set a key/value pair in the TXT record. Setting an existing key will replace its value.<P>
+		@param	key
+					The key name. Must be ASCII, with no '=' characters.
+		<P>
+		@param	value
+					Binary representation of the value.
+	*/
+	public void	set( String key, byte[] value)
+	{
+		byte[]	keyBytes;
+		int		valLen = (value != null) ? value.length : 0;
+
+		try {
+			keyBytes = key.getBytes( "US-ASCII");
+		}
+		catch ( java.io.UnsupportedEncodingException uee) {
+			throw new IllegalArgumentException();
+		}
+
+		for ( int i=0; i < keyBytes.length; i++)
+			if ( keyBytes[i] == '=')
+				throw new IllegalArgumentException();
+
+		if ( keyBytes.length + valLen >= 255)
+			throw new ArrayIndexOutOfBoundsException();
+
+		int		prevLoc = this.remove( key);
+		if ( prevLoc == -1)
+			prevLoc = this.size();
+
+		this.insert( keyBytes, value, prevLoc);
+	}
+
+	protected void	insert( byte[] keyBytes, byte[] value, int index)
+	// Insert a key-value pair at index
+	{
+		byte[]	oldBytes = fBytes;
+		int		valLen = (value != null) ? value.length : 0;
+		int		insertion = 0;
+		int		newLen, avLen;
+
+		// locate the insertion point
+		for ( int i=0; i < index && insertion < fBytes.length; i++)
+			insertion += (0xFF & (fBytes[ insertion] + 1));
+
+		avLen = keyBytes.length + valLen + (value != null ? 1 : 0);
+		newLen = avLen + oldBytes.length + 1;
+
+		fBytes = new byte[ newLen];
+		System.arraycopy( oldBytes, 0, fBytes, 0, insertion);
+		int secondHalfLen = oldBytes.length - insertion;
+		System.arraycopy( oldBytes, insertion, fBytes, newLen - secondHalfLen, secondHalfLen);
+		fBytes[ insertion] = ( byte) avLen;
+		System.arraycopy( keyBytes, 0, fBytes, insertion + 1, keyBytes.length);
+		if ( value != null)
+		{
+			fBytes[ insertion + 1 + keyBytes.length] = kAttrSep;
+			System.arraycopy( value, 0, fBytes, insertion + keyBytes.length + 2, valLen);
+		}
+	}
+
+	/** Remove a key/value pair from the TXT record. Returns index it was at, or -1 if not found. */
+	public int	remove( String key)
+	{
+		int		avStart = 0;
+
+		for ( int i=0; avStart < fBytes.length; i++)
+		{
+			int		avLen = fBytes[ avStart];
+			if ( key.length() <= avLen && 
+				 ( key.length() == avLen || fBytes[ avStart + key.length() + 1] == kAttrSep))
+			{
+				String	s = new String( fBytes, avStart + 1, key.length());
+				if ( 0 == key.compareToIgnoreCase( s))
+				{
+					byte[]	oldBytes = fBytes;
+					fBytes = new byte[ oldBytes.length - avLen - 1];
+					System.arraycopy( oldBytes, 0, fBytes, 0, avStart);
+					System.arraycopy( oldBytes, avStart + avLen + 1, fBytes, avStart, oldBytes.length - avStart - avLen - 1);
+					return i;
+				}
+			}
+			avStart += (0xFF & (avLen + 1));
+		}
+		return -1;
+	}
+
+	/**	Return the number of keys in the TXT record. */
+	public int	size()
+	{
+		int		i, avStart;
+
+		for ( i=0, avStart=0; avStart < fBytes.length; i++)
+			avStart += (0xFF & (fBytes[ avStart] + 1));
+		return i;
+	}
+
+	/** Return true if key is present in the TXT record, false if not. */
+	public boolean	contains( String key)
+	{		
+		String	s = null;
+
+		for ( int i=0; null != ( s = this.getKey( i)); i++)
+			if ( 0 == key.compareToIgnoreCase( s))
+				return true;
+		return false;
+	}
+
+	/**	Return a key in the TXT record by zero-based index. Returns null if index exceeds the total number of keys. */
+	public String	getKey( int index)
+	{
+		int		avStart = 0;
+
+		for ( int i=0; i < index && avStart < fBytes.length; i++)
+			avStart += fBytes[ avStart] + 1;
+
+		if ( avStart < fBytes.length)
+		{
+			int	avLen = fBytes[ avStart];
+			int	aLen = 0;
+
+			for ( aLen=0; aLen < avLen; aLen++)
+				if ( fBytes[ avStart + aLen + 1] == kAttrSep)
+					break;
+			return new String( fBytes, avStart + 1, aLen);
+		}
+		return null;
+	}
+
+	/**	
+		Look up a key in the TXT record by zero-based index and return its value. <P>
+		Returns null if index exceeds the total number of keys. 
+		Returns null if the key is present with no value.
+	*/
+	public byte[]	getValue( int index)
+	{
+		int		avStart = 0;
+		byte[]	value = null;
+
+		for ( int i=0; i < index && avStart < fBytes.length; i++)
+			avStart += fBytes[ avStart] + 1;
+
+		if ( avStart < fBytes.length)
+		{
+			int	avLen = fBytes[ avStart];
+			int	aLen = 0;
+
+			for ( aLen=0; aLen < avLen; aLen++)
+			{
+				if ( fBytes[ avStart + aLen + 1] == kAttrSep)
+				{
+					value = new byte[ avLen - aLen - 1];
+					System.arraycopy( fBytes, avStart + aLen + 2, value, 0, avLen - aLen - 1);
+					break;
+				}
+			}
+		}
+		return value;
+	}
+
+	/** Converts the result of getValue() to a string in the platform default character set. */
+	public String	getValueAsString( int index)
+	{
+		byte[]	value = this.getValue( index);
+		return value != null ? new String( value) : null;
+	}
+
+	/**	Get the value associated with a key. Will be null if the key is not defined.
+		Array will have length 0 if the key is defined with an = but no value.<P> 
+
+		@param	forKey
+					The left-hand side of the key-value pair.
+		<P>
+		@return		The binary representation of the value.
+	*/
+	public byte[]	getValue( String forKey)
+	{
+		String	s = null;
+		int		i;
+
+		for ( i=0; null != ( s = this.getKey( i)); i++)
+			if ( 0 == forKey.compareToIgnoreCase( s))
+				return this.getValue( i);
+		return null;
+	}
+
+	/**	Converts the result of getValue() to a string in the platform default character set.<P> 
+
+		@param	forKey
+					The left-hand side of the key-value pair.
+		<P>
+		@return		The value represented in the default platform character set.
+	*/
+	public String	getValueAsString( String forKey)
+	{
+		byte[]	val = this.getValue( forKey);
+		return val != null ? new String( val) : null;
+	}
+
+	/** Return the contents of the TXT record as raw bytes. */
+	public byte[]	getRawBytes() { return (byte[]) fBytes.clone(); }
+
+	/** Return a string representation of the object. */
+	public String	toString()
+	{
+		String		a, result = null;
+
+		for ( int i=0; null != ( a = this.getKey( i)); i++)
+		{
+			String av = String.valueOf( i) + "={" + a;
+			String val = this.getValueAsString( i);
+			if ( val != null)
+				av += "=" + val + "}";
+			else
+				av += "}";
+			if ( result == null)
+				result = av;
+			else
+				result = result + ", " + av;
+		}
+		return result != null ? result : "";
+	}
+}