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/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you 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:
*
* https://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 net.dreamlu.iot.mqtt.codec;
import net.dreamlu.iot.mqtt.codec.properties.*;
import org.tio.core.ChannelContext;
import org.tio.utils.buffer.ByteBufferAllocator;
import org.tio.utils.buffer.ByteBufferUtil;
import org.tio.utils.hutool.FastByteBuffer;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.List;
import static net.dreamlu.iot.mqtt.codec.MqttConstant.DEFAULT_MAX_CLIENT_ID_LENGTH;
/**
* Encodes Mqtt messages into bytes following the protocol specification v3.1
* as described here MQTTV3.1
* or v5.0 as described here MQTTv5.0 -
* depending on the version specified in the first CONNECT message that goes through the channel.
*
* @author netty
* @author L.cm
*/
public final class MqttEncoder {
public static final MqttEncoder INSTANCE = new MqttEncoder();
private MqttEncoder() {
}
/**
* This is the main encoding method.
* It's only visible for testing.
*
* @param ctx ChannelContext
* @param message MQTT message to encode
* @param allocator ByteBuffer Allocator
* @return ByteBuf with encoded bytes
*/
public ByteBuffer doEncode(ChannelContext ctx, MqttMessage message, ByteBufferAllocator allocator) {
switch (message.fixedHeader().messageType()) {
case CONNECT:
return encodeConnectMessage(ctx, (MqttConnectMessage) message, allocator);
case CONNACK:
return encodeConnAckMessage(ctx, (MqttConnAckMessage) message, allocator);
case PUBLISH:
return encodePublishMessage(ctx, (MqttPublishMessage) message, allocator);
case SUBSCRIBE:
return encodeSubscribeMessage(ctx, (MqttSubscribeMessage) message, allocator);
case UNSUBSCRIBE:
return encodeUnsubscribeMessage(ctx, (MqttUnsubscribeMessage) message, allocator);
case SUBACK:
return encodeSubAckMessage(ctx, (MqttSubAckMessage) message, allocator);
case UNSUBACK:
if (message instanceof MqttUnsubAckMessage) {
return encodeUnsubAckMessage(ctx, (MqttUnsubAckMessage) message, allocator);
}
return encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(message, allocator);
case PUBACK:
case PUBREC:
case PUBREL:
case PUBCOMP:
return encodePubReplyMessage(ctx, message, allocator);
case DISCONNECT:
case AUTH:
return encodeReasonCodePlusPropertiesMessage(ctx, message, allocator);
case PINGREQ:
case PINGRESP:
return encodeMessageWithOnlySingleByteFixedHeader(message, allocator);
default:
throw new IllegalArgumentException("Unknown message type: " + message.fixedHeader().messageType().value());
}
}
private static ByteBuffer encodeConnectMessage(ChannelContext ctx,
MqttConnectMessage message,
ByteBufferAllocator allocator) {
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttConnectVariableHeader variableHeader = message.variableHeader();
MqttConnectPayload payload = message.payload();
MqttVersion mqttVersion = MqttVersion.fromProtocolNameAndLevel(variableHeader.name(), (byte) variableHeader.version());
MqttCodecUtil.setMqttVersion(ctx, mqttVersion);
// as MQTT 3.1 & 3.1.1 spec, If the User Name Flag is set to 0, the Password Flag MUST be set to 0
if (!variableHeader.hasUserName() && variableHeader.hasPassword()) {
throw new EncoderException("Without a username, the password MUST be not set");
}
// Client id
String clientIdentifier = payload.clientIdentifier();
if (!MqttCodecUtil.isValidClientId(mqttVersion, DEFAULT_MAX_CLIENT_ID_LENGTH, clientIdentifier)) {
throw new MqttIdentifierRejectedException("invalid clientIdentifier: " + clientIdentifier);
}
byte[] clientIdentifierBytes = encodeStringUtf8(clientIdentifier);
payloadBufferSize += 2 + clientIdentifierBytes.length;
// Will topic and message
String willTopic = payload.willTopic();
byte[] willTopicBytes = willTopic != null ? encodeStringUtf8(willTopic) : ByteBufferUtil.EMPTY_BYTES;
byte[] willMessage = payload.willMessageInBytes();
byte[] willMessageBytes = willMessage != null ? willMessage : ByteBufferUtil.EMPTY_BYTES;
if (variableHeader.isWillFlag()) {
payloadBufferSize += 2 + willTopicBytes.length;
payloadBufferSize += 2 + willMessageBytes.length;
}
String userName = payload.userName();
byte[] userNameBytes = userName != null ? encodeStringUtf8(userName) : ByteBufferUtil.EMPTY_BYTES;
if (variableHeader.hasUserName()) {
payloadBufferSize += 2 + userNameBytes.length;
}
byte[] password = payload.passwordInBytes();
byte[] passwordBytes = password != null ? password : ByteBufferUtil.EMPTY_BYTES;
if (variableHeader.hasPassword()) {
payloadBufferSize += 2 + passwordBytes.length;
}
// Fixed and variable header
byte[] protocolNameBytes = mqttVersion.protocolNameBytes();
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion, message.variableHeader().properties());
final byte[] willPropertiesBytes;
if (variableHeader.isWillFlag()) {
willPropertiesBytes = encodePropertiesIfNeeded(mqttVersion, payload.willProperties());
payloadBufferSize += willPropertiesBytes.length;
} else {
willPropertiesBytes = ByteBufferUtil.EMPTY_BYTES;
}
int variableHeaderBufferSize = 2 + protocolNameBytes.length + 4 + propertiesBytes.length;
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
// 申请 ByteBuffer
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
buf.putShort((short) protocolNameBytes.length);
buf.put(protocolNameBytes);
buf.put((byte) variableHeader.version());
buf.put((byte) getConnVariableHeaderFlag(variableHeader));
buf.putShort((short) variableHeader.keepAliveTimeSeconds());
buf.put(propertiesBytes);
// Payload
buf.putShort((short) clientIdentifierBytes.length);
buf.put(clientIdentifierBytes, 0, clientIdentifierBytes.length);
if (variableHeader.isWillFlag()) {
buf.put(willPropertiesBytes, 0, willPropertiesBytes.length);
buf.putShort((short) willTopicBytes.length);
buf.put(willTopicBytes, 0, willTopicBytes.length);
buf.putShort((short) willMessageBytes.length);
buf.put(willMessageBytes, 0, willMessageBytes.length);
}
if (variableHeader.hasUserName()) {
buf.putShort((short) userNameBytes.length);
buf.put(userNameBytes, 0, userNameBytes.length);
}
if (variableHeader.hasPassword()) {
buf.putShort((short) passwordBytes.length);
buf.put(passwordBytes, 0, passwordBytes.length);
}
return buf;
}
private static int getConnVariableHeaderFlag(MqttConnectVariableHeader variableHeader) {
int flagByte = 0;
if (variableHeader.hasUserName()) {
flagByte |= 0x80;
}
if (variableHeader.hasPassword()) {
flagByte |= 0x40;
}
if (variableHeader.isWillRetain()) {
flagByte |= 0x20;
}
flagByte |= (variableHeader.willQos() & 0x03) << 3;
if (variableHeader.isWillFlag()) {
flagByte |= 0x04;
}
if (variableHeader.isCleanSession()) {
flagByte |= 0x02;
}
return flagByte;
}
private static ByteBuffer encodeConnAckMessage(ChannelContext ctx,
MqttConnAckMessage message,
ByteBufferAllocator allocator) {
final MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion, message.variableHeader().properties());
ByteBuffer buf = allocator.allocate(4 + propertiesBytes.length);
buf.put(getFixedHeaderByte1(message.fixedHeader()));
writeVariableLengthInt(buf, 2 + propertiesBytes.length);
buf.put((byte) (message.variableHeader().isSessionPresent() ? 0x01 : 0x00));
buf.put(message.variableHeader().connectReturnCode().value());
buf.put(propertiesBytes);
return buf;
}
private static ByteBuffer encodeSubscribeMessage(ChannelContext ctx,
MqttSubscribeMessage message,
ByteBufferAllocator allocator) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion,
message.idAndPropertiesVariableHeader().properties());
final int variableHeaderBufferSize = 2 + propertiesBytes.length;
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = message.variableHeader();
MqttSubscribePayload payload = message.payload();
for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
String topicName = topic.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
payloadBufferSize += 2 + topicNameBytes.length;
payloadBufferSize += 1;
}
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
// Variable Header
int messageId = variableHeader.messageId();
buf.putShort((short) messageId);
buf.put(propertiesBytes);
// Payload
for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
// topicName
String topicName = topic.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
buf.putShort((short) topicNameBytes.length);
buf.put(topicNameBytes, 0, topicNameBytes.length);
if (mqttVersion == MqttVersion.MQTT_3_1_1 || mqttVersion == MqttVersion.MQTT_3_1) {
buf.put((byte) topic.qualityOfService().value());
} else {
// option
final MqttSubscriptionOption option = topic.option();
int optionEncoded = option.retainHandling().value() << 4;
if (option.isRetainAsPublished()) {
optionEncoded |= 0x08;
}
if (option.isNoLocal()) {
optionEncoded |= 0x04;
}
optionEncoded |= option.qos().value();
buf.put((byte) optionEncoded);
}
}
return buf;
}
private static ByteBuffer encodeUnsubscribeMessage(ChannelContext ctx,
MqttUnsubscribeMessage message,
ByteBufferAllocator allocator) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion,
message.idAndPropertiesVariableHeader().properties());
final int variableHeaderBufferSize = 2 + propertiesBytes.length;
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = message.variableHeader();
MqttUnsubscribePayload payload = message.payload();
for (String topicName : payload.topics()) {
byte[] topicNameBytes = encodeStringUtf8(topicName);
payloadBufferSize += 2 + topicNameBytes.length;
}
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
// Variable Header
int messageId = variableHeader.messageId();
buf.putShort((short) messageId);
buf.put(propertiesBytes);
// Payload
for (String topicName : payload.topics()) {
// topicName
byte[] topicNameBytes = encodeStringUtf8(topicName);
buf.putShort((short) topicNameBytes.length);
buf.put(topicNameBytes, 0, topicNameBytes.length);
}
return buf;
}
private static ByteBuffer encodeSubAckMessage(ChannelContext ctx,
MqttSubAckMessage message,
ByteBufferAllocator allocator) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion,
message.idAndPropertiesVariableHeader().properties());
int variableHeaderBufferSize = 2 + propertiesBytes.length;
int payloadBufferSize = message.payload().grantedQoSLevels().size();
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(message.fixedHeader()));
writeVariableLengthInt(buf, variablePartSize);
buf.putShort((short) message.variableHeader().messageId());
buf.put(propertiesBytes);
for (Short code : message.payload().reasonCodes()) {
buf.put(code.byteValue());
}
return buf;
}
private static ByteBuffer encodeUnsubAckMessage(ChannelContext ctx,
MqttUnsubAckMessage message,
ByteBufferAllocator allocator) {
if (message.variableHeader() instanceof MqttMessageIdAndPropertiesVariableHeader) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion, message.idAndPropertiesVariableHeader().properties());
int variableHeaderBufferSize = 2 + propertiesBytes.length;
MqttUnsubAckPayload payload = message.payload();
int payloadBufferSize = payload == null ? 0 : payload.unsubscribeReasonCodes().size();
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(message.fixedHeader()));
writeVariableLengthInt(buf, variablePartSize);
buf.putShort((short) message.variableHeader().messageId());
buf.put(propertiesBytes);
if (payload != null) {
for (Short reasonCode : payload.unsubscribeReasonCodes()) {
buf.putShort(reasonCode);
}
}
return buf;
} else {
return encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(message, allocator);
}
}
private static ByteBuffer encodePublishMessage(ChannelContext ctx,
MqttPublishMessage message,
ByteBufferAllocator allocator) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttPublishVariableHeader variableHeader = message.variableHeader();
byte[] payload = message.payload() == null ? ByteBufferUtil.EMPTY_BYTES : message.getPayload();
String topicName = variableHeader.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
byte[] propertiesBytes = encodePropertiesIfNeeded(mqttVersion,
message.variableHeader().properties());
int variableHeaderBufferSize = 2 + topicNameBytes.length +
(mqttFixedHeader.qosLevel().value() > 0 ? 2 : 0) + propertiesBytes.length;
int payloadBufferSize = payload.length;
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variablePartSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
buf.putShort((short) topicNameBytes.length);
buf.put(topicNameBytes);
if (mqttFixedHeader.qosLevel().value() > 0) {
buf.putShort((short) variableHeader.packetId());
}
buf.put(propertiesBytes);
buf.put(payload);
return buf;
}
private static ByteBuffer encodePubReplyMessage(ChannelContext ctx,
MqttMessage message,
ByteBufferAllocator allocator) {
if (message.variableHeader() instanceof MqttPubReplyMessageVariableHeader) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttPubReplyMessageVariableHeader variableHeader =
(MqttPubReplyMessageVariableHeader) message.variableHeader();
final byte[] propertiesBytes;
final boolean includeReasonCode;
final int variableHeaderBufferSize;
final MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
if (mqttVersion == MqttVersion.MQTT_5 &&
(variableHeader.reasonCode() != MqttPubReplyMessageVariableHeader.REASON_CODE_OK ||
!variableHeader.properties().isEmpty())) {
propertiesBytes = encodeProperties(variableHeader.properties());
includeReasonCode = true;
variableHeaderBufferSize = 3 + propertiesBytes.length;
} else {
propertiesBytes = ByteBufferUtil.EMPTY_BYTES;
includeReasonCode = false;
variableHeaderBufferSize = 2;
}
final int fixedHeaderBufferSize = 1 + getVariableLengthInt(variableHeaderBufferSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variableHeaderBufferSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variableHeaderBufferSize);
buf.putShort((short) variableHeader.messageId());
if (includeReasonCode) {
buf.put(variableHeader.reasonCode());
}
buf.put(propertiesBytes);
return buf;
} else {
return encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(message, allocator);
}
}
private static ByteBuffer encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(MqttMessage message,
ByteBufferAllocator allocator) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = (MqttMessageIdVariableHeader) message.variableHeader();
// variable part only has a message id
int variableHeaderBufferSize = 2;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variableHeaderBufferSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variableHeaderBufferSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variableHeaderBufferSize);
buf.putShort((short) variableHeader.messageId());
return buf;
}
private static ByteBuffer encodeReasonCodePlusPropertiesMessage(ChannelContext ctx,
MqttMessage message,
ByteBufferAllocator allocator) {
if (message.variableHeader() instanceof MqttReasonCodeAndPropertiesVariableHeader) {
MqttVersion mqttVersion = MqttCodecUtil.getMqttVersion(ctx);
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttReasonCodeAndPropertiesVariableHeader variableHeader =
(MqttReasonCodeAndPropertiesVariableHeader) message.variableHeader();
final byte[] propertiesBytes;
final boolean includeReasonCode;
final int variableHeaderBufferSize;
if (mqttVersion == MqttVersion.MQTT_5 &&
(variableHeader.reasonCode() != MqttReasonCodeAndPropertiesVariableHeader.REASON_CODE_OK ||
!variableHeader.properties().isEmpty())) {
propertiesBytes = encodeProperties(variableHeader.properties());
includeReasonCode = true;
variableHeaderBufferSize = 1 + propertiesBytes.length;
} else {
propertiesBytes = ByteBufferUtil.EMPTY_BYTES;
includeReasonCode = false;
variableHeaderBufferSize = 0;
}
final int fixedHeaderBufferSize = 1 + getVariableLengthInt(variableHeaderBufferSize);
ByteBuffer buf = allocator.allocate(fixedHeaderBufferSize + variableHeaderBufferSize);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variableHeaderBufferSize);
if (includeReasonCode) {
buf.put(variableHeader.reasonCode());
}
buf.put(propertiesBytes);
return buf;
} else {
return encodeMessageWithOnlySingleByteFixedHeader(message, allocator);
}
}
private static ByteBuffer encodeMessageWithOnlySingleByteFixedHeader(MqttMessage message,
ByteBufferAllocator allocator) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
ByteBuffer buf = allocator.allocate(2);
buf.put(getFixedHeaderByte1(mqttFixedHeader));
buf.put((byte) 0);
return buf;
}
private static byte[] encodePropertiesIfNeeded(MqttVersion mqttVersion,
MqttProperties mqttProperties) {
if (mqttVersion == MqttVersion.MQTT_5) {
return encodeProperties(mqttProperties);
}
return ByteBufferUtil.EMPTY_BYTES;
}
private static byte[] encodeProperties(MqttProperties mqttProperties) {
FastByteBuffer writeBuffer = new FastByteBuffer(256);
for (MqttProperty property : mqttProperties.listAll()) {
int propertyId = property.propertyId();
MqttPropertyType propertyType = MqttPropertyType.valueOf(propertyId);
switch (propertyType) {
case PAYLOAD_FORMAT_INDICATOR:
case REQUEST_PROBLEM_INFORMATION:
case REQUEST_RESPONSE_INFORMATION:
case MAXIMUM_QOS:
case RETAIN_AVAILABLE:
case WILDCARD_SUBSCRIPTION_AVAILABLE:
case SUBSCRIPTION_IDENTIFIER_AVAILABLE:
case SHARED_SUBSCRIPTION_AVAILABLE:
writeBuffer.writeVarLengthInt(propertyId);
final byte bytePropValue = ((IntegerProperty) property).value().byteValue();
writeBuffer.writeByte(bytePropValue);
break;
case SERVER_KEEP_ALIVE:
case RECEIVE_MAXIMUM:
case TOPIC_ALIAS_MAXIMUM:
case TOPIC_ALIAS:
writeBuffer.writeVarLengthInt(propertyId);
final short twoBytesInPropValue =
((IntegerProperty) property).value().shortValue();
writeBuffer.writeShortBE(twoBytesInPropValue);
break;
case PUBLICATION_EXPIRY_INTERVAL:
case SESSION_EXPIRY_INTERVAL:
case WILL_DELAY_INTERVAL:
case MAXIMUM_PACKET_SIZE:
writeBuffer.writeVarLengthInt(propertyId);
final int fourBytesIntPropValue = ((IntegerProperty) property).value();
writeBuffer.writeIntBE(fourBytesIntPropValue);
break;
case SUBSCRIPTION_IDENTIFIER:
writeBuffer.writeVarLengthInt(propertyId);
final int vbi = ((IntegerProperty) property).value();
writeBuffer.writeVarLengthInt(vbi);
break;
case CONTENT_TYPE:
case RESPONSE_TOPIC:
case ASSIGNED_CLIENT_IDENTIFIER:
case AUTHENTICATION_METHOD:
case RESPONSE_INFORMATION:
case SERVER_REFERENCE:
case REASON_STRING:
writeBuffer.writeVarLengthInt(propertyId);
writeEagerUTF8String(writeBuffer, ((StringProperty) property).value());
break;
case USER_PROPERTY:
final List pairs =
((UserProperties) property).value();
for (StringPair pair : pairs) {
writeBuffer.writeVarLengthInt(propertyId);
writeEagerUTF8String(writeBuffer, pair.key);
writeEagerUTF8String(writeBuffer, pair.value);
}
break;
case CORRELATION_DATA:
case AUTHENTICATION_DATA:
writeBuffer.writeVarLengthInt(propertyId);
final byte[] binaryPropValue = ((BinaryProperty) property).value();
writeBuffer.writeShortBE((short) binaryPropValue.length);
writeBuffer.writeBytes(binaryPropValue, 0, binaryPropValue.length);
break;
default:
//shouldn't reach here
throw new EncoderException("Unknown property type: " + propertyType);
}
}
byte[] propertiesBytes = writeBuffer.toArray();
writeBuffer.reset();
writeBuffer.writeVarLengthInt(propertiesBytes.length);
writeBuffer.writeBytes(propertiesBytes);
return writeBuffer.toArray();
}
private static byte getFixedHeaderByte1(MqttFixedHeader header) {
byte ret = 0;
ret |= header.messageType().value() << 4;
if (header.isDup()) {
ret |= 0x08;
}
ret |= header.qosLevel().value() << 1;
if (header.isRetain()) {
ret |= 0x01;
}
return ret;
}
private static void writeVariableLengthInt(ByteBuffer buf, int num) {
do {
int digit = num % 128;
num /= 128;
if (num > 0) {
digit |= 0x80;
}
buf.put((byte) digit);
} while (num > 0);
}
private static int getVariableLengthInt(int num) {
int count = 0;
do {
num /= 128;
count++;
} while (num > 0);
return count;
}
private static void writeEagerUTF8String(FastByteBuffer buf, String s) {
if (s == null) {
buf.writeShortBE((short) 0);
} else {
byte[] bytes = s.getBytes(StandardCharsets.UTF_8);
buf.writeShortBE((short) bytes.length);
buf.writeBytes(bytes);
}
}
private static byte[] encodeStringUtf8(String s) {
return s.getBytes(StandardCharsets.UTF_8);
}
}
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