static void serializeConnectPacket()

in source/core_mqtt_serializer.c [1393:1508]
77 lines of code
11 McCabe index (conditional complexity)

static void serializeConnectPacket( const MQTTConnectInfo_t * pConnectInfo,
                                    const MQTTPublishInfo_t * pWillInfo,
                                    size_t remainingLength,
                                    const MQTTFixedBuffer_t * pFixedBuffer )
{
    uint8_t connectFlags = 0U;
    uint8_t * pIndex = NULL;

    assert( pConnectInfo != NULL );
    assert( pFixedBuffer != NULL );
    assert( pFixedBuffer->pBuffer != NULL );

    pIndex = pFixedBuffer->pBuffer;
    /* The first byte in the CONNECT packet is the control packet type. */
    *pIndex = MQTT_PACKET_TYPE_CONNECT;
    pIndex++;

    /* The remaining length of the CONNECT packet is encoded starting from the
     * second byte. The remaining length does not include the length of the fixed
     * header or the encoding of the remaining length. */
    pIndex = encodeRemainingLength( pIndex, remainingLength );

    /* The string "MQTT" is placed at the beginning of the CONNECT packet's variable
     * header. This string is 4 bytes long. */
    pIndex = encodeString( pIndex, "MQTT", 4 );

    /* The MQTT protocol version is the second field of the variable header. */
    *pIndex = MQTT_VERSION_3_1_1;
    pIndex++;

    /* Set the clean session flag if needed. */
    if( pConnectInfo->cleanSession == true )
    {
        UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_CLEAN );
    }

    /* Set the flags for username and password if provided. */
    if( pConnectInfo->pUserName != NULL )
    {
        UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_USERNAME );
    }

    if( pConnectInfo->pPassword != NULL )
    {
        UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_PASSWORD );
    }

    /* Set will flag if a Last Will and Testament is provided. */
    if( pWillInfo != NULL )
    {
        UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_WILL );

        /* Flags only need to be changed for Will QoS 1 or 2. */
        if( pWillInfo->qos == MQTTQoS1 )
        {
            UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_WILL_QOS1 );
        }
        else if( pWillInfo->qos == MQTTQoS2 )
        {
            UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_WILL_QOS2 );
        }
        else
        {
            /* Empty else MISRA 15.7 */
        }

        if( pWillInfo->retain == true )
        {
            UINT8_SET_BIT( connectFlags, MQTT_CONNECT_FLAG_WILL_RETAIN );
        }
    }

    *pIndex = connectFlags;
    pIndex++;

    /* Write the 2 bytes of the keep alive interval into the CONNECT packet. */
    *pIndex = UINT16_HIGH_BYTE( pConnectInfo->keepAliveSeconds );
    *( pIndex + 1 ) = UINT16_LOW_BYTE( pConnectInfo->keepAliveSeconds );
    pIndex += 2;

    /* Write the client identifier into the CONNECT packet. */
    pIndex = encodeString( pIndex,
                           pConnectInfo->pClientIdentifier,
                           pConnectInfo->clientIdentifierLength );

    /* Write the will topic name and message into the CONNECT packet if provided. */
    if( pWillInfo != NULL )
    {
        pIndex = encodeString( pIndex,
                               pWillInfo->pTopicName,
                               pWillInfo->topicNameLength );

        pIndex = encodeString( pIndex,
                               pWillInfo->pPayload,
                               ( uint16_t ) pWillInfo->payloadLength );
    }

    /* Encode the user name if provided. */
    if( pConnectInfo->pUserName != NULL )
    {
        pIndex = encodeString( pIndex, pConnectInfo->pUserName, pConnectInfo->userNameLength );
    }

    /* Encode the password if provided. */
    if( pConnectInfo->pPassword != NULL )
    {
        pIndex = encodeString( pIndex, pConnectInfo->pPassword, pConnectInfo->passwordLength );
    }

    LogDebug( ( "Length of serialized CONNECT packet is %lu.",
                ( ( unsigned long ) ( pIndex - pFixedBuffer->pBuffer ) ) ) );

    /* Ensure that the difference between the end and beginning of the buffer
     * is less than the buffer size. */
    assert( ( ( size_t ) ( pIndex - pFixedBuffer->pBuffer ) ) <= pFixedBuffer->size );
}