Micro-XRCE-DDS-Client/examples/SubscribeHelloWorldBestEffort/main.c

// Copyright 2021 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// 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.

#include "HelloWorld.h"

#include <uxr/client/client.h>

#include <stdio.h> //printf
#include <string.h> //strcmp
#include <stdlib.h> //atoi

#define STREAM_HISTORY  8
#define BUFFER_SIZE     UXR_CONFIG_UDP_TRANSPORT_MTU* STREAM_HISTORY

void on_topic(
        uxrSession* session,
        uxrObjectId object_id,
        uint16_t request_id,
        uxrStreamId stream_id,
        struct ucdrBuffer* ub,
        uint16_t length,
        void* args)
{
    (void) session; (void) object_id; (void) request_id; (void) stream_id; (void) length;

    HelloWorld topic;
    HelloWorld_deserialize_topic(ub, &topic);

    printf("Received topic: %s, id: %i\n", topic.message, topic.index);

    uint32_t* count_ptr = (uint32_t*) args;
    (*count_ptr)++;
}

int main(
        int args,
        char** argv)
{
    // CLI
    if (3 > args || 0 == atoi(argv[2]))
    {
        printf("usage: program [-h | --help] | ip port [<max_topics>]\n");
        return 0;
    }

    char* ip = argv[1];
    char* port =  argv[2];
    uint32_t max_topics = (args == 4) ? (uint32_t)atoi(argv[3]) : UINT32_MAX;

    // State
    uint32_t count = 0;

    // Transport
    uxrUDPTransport transport;
    if (!uxr_init_udp_transport(&transport, UXR_IPv4, ip, port))
    {
        printf("Error at create transport.\n");
        return 1;
    }

    // Session
    uxrSession session;
    uxr_init_session(&session, &transport.comm, 0xCCCCDDDD);
    uxr_set_topic_callback(&session, on_topic, &count);
    if (!uxr_create_session(&session))
    {
        printf("Error at create session.\n");
        return 1;
    }

    // Streams
    uint8_t output_reliable_stream_buffer[BUFFER_SIZE];
    uxrStreamId reliable_out = uxr_create_output_reliable_stream(&session, output_reliable_stream_buffer, BUFFER_SIZE,
                    STREAM_HISTORY);

    uint8_t input_reliable_stream_buffer[BUFFER_SIZE];
    uxr_create_input_reliable_stream(&session, input_reliable_stream_buffer, BUFFER_SIZE, STREAM_HISTORY);

    uxrStreamId besteffort_in = uxr_create_input_best_effort_stream(&session);

    // Create entities
    uxrObjectId participant_id = uxr_object_id(0x01, UXR_PARTICIPANT_ID);
    const char* participant_xml = "<dds>"
            "<participant>"
            "<rtps>"
            "<name>default_xrce_participant</name>"
            "</rtps>"
            "</participant>"
            "</dds>";
    uint16_t participant_req = uxr_buffer_create_participant_xml(&session, reliable_out, participant_id, 0,
                    participant_xml, UXR_REPLACE);

    uxrObjectId topic_id = uxr_object_id(0x01, UXR_TOPIC_ID);
    const char* topic_xml = "<dds>"
            "<topic>"
            "<name>HelloWorldTopic</name>"
            "<dataType>HelloWorld</dataType>"
            "</topic>"
            "</dds>";
    uint16_t topic_req = uxr_buffer_create_topic_xml(&session, reliable_out, topic_id, participant_id, topic_xml,
                    UXR_REPLACE);

    uxrObjectId subscriber_id = uxr_object_id(0x01, UXR_SUBSCRIBER_ID);
    const char* subscriber_xml = "";
    uint16_t subscriber_req = uxr_buffer_create_subscriber_xml(&session, reliable_out, subscriber_id, participant_id,
                    subscriber_xml, UXR_REPLACE);

    uxrObjectId datareader_id = uxr_object_id(0x01, UXR_DATAREADER_ID);
    const char* datareader_xml = "<dds>"
            "<data_reader>"
            "<topic>"
            "<kind>NO_KEY</kind>"
            "<name>HelloWorldTopic</name>"
            "<dataType>HelloWorld</dataType>"
            "</topic>"
            "</data_reader>"
            "</dds>";
    uint16_t datareader_req = uxr_buffer_create_datareader_xml(&session, reliable_out, datareader_id, subscriber_id,
                    datareader_xml, UXR_REPLACE);

    // Send create entities message and wait its status
    uint8_t status[4];
    uint16_t requests[4] = {
        participant_req, topic_req, subscriber_req, datareader_req
    };
    if (!uxr_run_session_until_all_status(&session, 1000, requests, status, 4))
    {
        printf("Error at create entities: participant: %i topic: %i subscriber: %i datareader: %i\n", status[0],
                status[1], status[2], status[3]);
        return 1;
    }

    // Request topics
    uxrDeliveryControl delivery_control = {
        0
    };
    delivery_control.max_samples = UXR_MAX_SAMPLES_UNLIMITED;
    uxr_buffer_request_data(&session, reliable_out, datareader_id, besteffort_in,
            &delivery_control);

    // Read topics
    while (count < max_topics)
    {
        uxr_run_session_time(&session, 1000);
    }

    // Delete resources
    uxr_delete_session(&session);
    uxr_close_udp_transport(&transport);

    return 0;
}