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Original DnsSd TxtRecord file

Change-Id: I4aa308a3b417d6bdce50567fb66c7119b048140a
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1 parent 6756f74 commit 26d4452a08813cdbb7280c475fe5527cdc9673a3 @isheriff isheriff committed Apr 3, 2012
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  1. +11 −0 NOTICE
  2. +289 −0 core/java/android/net/nsd/DnsSdTxtRecord.java
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11 NOTICE
@@ -56,6 +56,17 @@ 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, ==
== in this case for the TagSoup code. ==
=========================================================================
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289 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 : "";
+ }
+}

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