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/*
* Copyright (C) 2010 The Android Open Source Project
*
* 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.
*/
package com.android.nfc.ndefpush;
import android.util.Log;
import android.nfc.NdefMessage;
import android.nfc.FormatException;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
/**
* Implementation of the NDEF Push Protocol.
*/
public class NdefPushProtocol {
public static final byte ACTION_IMMEDIATE = (byte) 0x01;
public static final byte ACTION_BACKGROUND = (byte) 0x02;
private static final String TAG = "NdefMessageSet";
private static final byte VERSION = 1;
private int mNumMessages;
private byte[] mActions;
private NdefMessage[] mMessages;
public NdefPushProtocol(NdefMessage msg, byte action) {
mNumMessages = 1;
mActions = new byte[1];
mActions[0] = action;
mMessages = new NdefMessage[1];
mMessages[0] = msg;
}
public NdefPushProtocol(byte[] actions, NdefMessage[] messages) {
if (actions.length != messages.length || actions.length == 0) {
throw new IllegalArgumentException(
"actions and messages must be the same size and non-empty");
}
// Keep a copy of these arrays
int numMessages = actions.length;
mActions = new byte[numMessages];
System.arraycopy(actions, 0, mActions, 0, numMessages);
mMessages = new NdefMessage[numMessages];
System.arraycopy(messages, 0, mMessages, 0, numMessages);
mNumMessages = numMessages;
}
public NdefPushProtocol(byte[] data) throws FormatException {
ByteArrayInputStream buffer = new ByteArrayInputStream(data);
DataInputStream input = new DataInputStream(buffer);
// Check version of protocol
byte version;
try {
version = input.readByte();
} catch (java.io.IOException e) {
Log.w(TAG, "Unable to read version");
throw new FormatException("Unable to read version");
}
if(version != VERSION) {
Log.w(TAG, "Got version " + version + ", expected " + VERSION);
throw new FormatException("Got version " + version + ", expected " + VERSION);
}
// Read numMessages
try {
mNumMessages = input.readInt();
} catch(java.io.IOException e) {
Log.w(TAG, "Unable to read numMessages");
throw new FormatException("Error while parsing NdefMessageSet");
}
if(mNumMessages == 0) {
Log.w(TAG, "No NdefMessage inside NdefMessageSet packet");
throw new FormatException("Error while parsing NdefMessageSet");
}
// Read actions and messages
mActions = new byte[mNumMessages];
mMessages = new NdefMessage[mNumMessages];
for(int i = 0; i < mNumMessages; i++) {
// Read action
try {
mActions[i] = input.readByte();
} catch(java.io.IOException e) {
Log.w(TAG, "Unable to read action for message " + i);
throw new FormatException("Error while parsing NdefMessageSet");
}
// Read message length
int length;
try {
length = input.readInt();
} catch(java.io.IOException e) {
Log.w(TAG, "Unable to read length for message " + i);
throw new FormatException("Error while parsing NdefMessageSet");
}
byte[] bytes = new byte[length];
// Read message
int lengthRead;
try {
lengthRead = input.read(bytes);
} catch(java.io.IOException e) {
Log.w(TAG, "Unable to read bytes for message " + i);
throw new FormatException("Error while parsing NdefMessageSet");
}
if(length != lengthRead) {
Log.w(TAG, "Read " + lengthRead + " bytes but expected " +
length);
throw new FormatException("Error while parsing NdefMessageSet");
}
// Create and store NdefMessage
try {
mMessages[i] = new NdefMessage(bytes);
} catch(FormatException e) {
throw e;
}
}
}
public NdefMessage getImmediate() {
// Find and return the first immediate message
for(int i = 0; i < mNumMessages; i++) {
if(mActions[i] == ACTION_IMMEDIATE) {
return mMessages[i];
}
}
return null;
}
public byte[] toByteArray() {
ByteArrayOutputStream buffer = new ByteArrayOutputStream(1024);
DataOutputStream output = new DataOutputStream(buffer);
try {
output.writeByte(VERSION);
output.writeInt(mNumMessages);
for(int i = 0; i < mNumMessages; i++) {
output.writeByte(mActions[i]);
byte[] bytes = mMessages[i].toByteArray();
output.writeInt(bytes.length);
output.write(bytes);
}
} catch(java.io.IOException e) {
return null;
}
return buffer.toByteArray();
}
}
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