From 546c8348aa071a46ee580f0dbfa1752fd4398623 Mon Sep 17 00:00:00 2001
From: Wiebe Cazemier <wiebe@halfgaar.net>
Date: Mon, 27 Jun 2022 12:53:12 +0200
Subject: [PATCH] Add parseSubAckData()

---
 mqttpacket.cpp    | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 mqttpacket.h      |  1 +
 packetdatatypes.h |  7 +++++++
 3 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/mqttpacket.cpp b/mqttpacket.cpp
index 946edcf..d87e72b 100644
--- a/mqttpacket.cpp
+++ b/mqttpacket.cpp
@@ -1275,6 +1275,52 @@ void MqttPacket::handlePubComp()
     sender->getSession()->removeOutgoingQoS2MessageId(packet_id);
 }
 
+SubAckData MqttPacket::parseSubAckData()
+{
+    if (this->packetType != PacketType::SUBACK)
+        throw std::runtime_error("Packet must be suback packet.");
+
+    setPosToDataStart();
+
+    SubAckData result;
+
+    result.packet_id = readTwoBytesToUInt16();
+    this->packet_id = result.packet_id;
+
+    if (this->protocolVersion >= ProtocolVersion::Mqtt5 )
+    {
+        const size_t proplen = decodeVariableByteIntAtPos();
+        const size_t prop_end_at = pos + proplen;
+
+        while (pos < prop_end_at)
+        {
+            const Mqtt5Properties prop = static_cast<Mqtt5Properties>(readByte());
+
+            switch (prop)
+            {
+            case Mqtt5Properties::ReasonString:
+                result.reasonString = readBytesToString();
+                break;
+            case Mqtt5Properties::UserProperty:
+                readUserProperty();
+                break;
+            default:
+                throw ProtocolError("Invalid property in suback.", ReasonCodes::ProtocolError);
+            }
+        }
+    }
+
+    // payload starts here
+
+    while (!atEnd())
+    {
+        uint8_t code = readByte();
+        result.subAckCodes.push_back(code);
+    }
+
+    return result;
+}
+
 void MqttPacket::calculateRemainingLength()
 {
     assert(fixed_header_length == 0); // because you're not supposed to call this on packet that we already know the length of.
diff --git a/mqttpacket.h b/mqttpacket.h
index e6ba3a6..0cd093d 100644
--- a/mqttpacket.h
+++ b/mqttpacket.h
@@ -124,6 +124,7 @@ public:
     void handlePubRec();
     void handlePubRel();
     void handlePubComp();
+    SubAckData parseSubAckData();
 
     uint8_t getFixedHeaderLength() const;
     size_t getSizeIncludingNonPresentHeader() const;
diff --git a/packetdatatypes.h b/packetdatatypes.h
index adce03f..1b1925e 100644
--- a/packetdatatypes.h
+++ b/packetdatatypes.h
@@ -47,5 +47,12 @@ struct DisconnectData
     uint32_t session_expiry_interval = 0;
 };
 
+struct SubAckData
+{
+    uint16_t packet_id;
+    std::string reasonString;
+    std::vector<uint8_t> subAckCodes;
+};
+
 
 #endif // PACKETDATATYPES_H
--
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