tcp_example2.c

#include "gps/navigation.h"
#include "gps/sbp.h"
#include "gps/system.h"

#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

char* tcp_ip_addr = NULL;
char* tcp_ip_port = NULL;

/* SBP structs that messages from Piksi will feed. */
msg_pos_llh_t pos_llh;
msg_baseline_ned_t baseline_ned;
msg_vel_ned_t vel_ned;
msg_dops_t dops;
msg_gps_time_t gps_time;

/*
 * SBP callback nodes must be statically allocated. Each message ID / callback
 * pair must have a unique sbp_msg_callbacks_node_t associated with it.
 */
sbp_msg_callbacks_node_t pos_llh_node;
sbp_msg_callbacks_node_t baseline_ned_node;
sbp_msg_callbacks_node_t vel_ned_node;
sbp_msg_callbacks_node_t dops_node;
sbp_msg_callbacks_node_t gps_time_node;

int socket_desc = -1;

void usage(char* prog_name) {
    fprintf(stderr, "usage: %s [-a address -p port]\n", prog_name);
}

void setup_socket() {
    struct sockaddr_in server;
    socket_desc = socket(AF_INET, SOCK_STREAM, 0);
    if (socket_desc == -1) {
        fprintf(stderr, "Could not create socket\n");
    }

    memset(&server, '0', sizeof(server));
    server.sin_addr.s_addr = inet_addr(tcp_ip_addr);
    server.sin_family = AF_INET;
    server.sin_port = htons(atoi(tcp_ip_port));

    if (connect(socket_desc, (struct sockaddr*)&server, sizeof(server)) < 0) {
        fprintf(stderr, "Connection error\n");
    }
}

void close_socket() {
    close(socket_desc);
}

void sbp_pos_llh_callback(u16 sender_id, u8 len, u8 msg[], void* context) {
    pos_llh = *(msg_pos_llh_t*)msg;
}

void sbp_baseline_ned_callback(u16 sender_id, u8 len, u8 msg[], void* context) {
    baseline_ned = *(msg_baseline_ned_t*)msg;
}

void sbp_vel_ned_callback(u16 sender_id, u8 len, u8 msg[], void* context) {
    vel_ned = *(msg_vel_ned_t*)msg;
}

void sbp_dops_callback(u16 sender_id, u8 len, u8 msg[], void* context) {
    dops = *(msg_dops_t*)msg;
}

void sbp_gps_time_callback(u16 sender_id, u8 len, u8 msg[], void* context) {
    gps_time = *(msg_gps_time_t*)msg;
}

u32 socket_read(u8* buff, u32 n, void* context) {
    (void)context;
    u32 result;

    result = read(socket_desc, buff, n);
    return result;
}

int main(int argc, char** argv) {
    int opt;
    int result = 0;
    sbp_state_t s;

    if (argc <= 2) {
        usage(argv[0]);
        exit(EXIT_FAILURE);
    }

    while ((opt = getopt(argc, argv, "a:p:")) != -1) {
        switch (opt) {
            case 'a':
                tcp_ip_addr = (char*)calloc(strlen(optarg) + 1, sizeof(char));
                if (!tcp_ip_addr) {
                    fprintf(stderr, "Cannot allocate memory!\n");
                    exit(EXIT_FAILURE);
                }
                strcpy(tcp_ip_addr, optarg);
                break;
            case 'p':
                tcp_ip_port = (char*)calloc(strlen(optarg) + 1, sizeof(char));
                if (!tcp_ip_port) {
                    fprintf(stderr, "Cannot allocate memory!\n");
                    exit(EXIT_FAILURE);
                }
                strcpy(tcp_ip_port, optarg);
                break;
            case 'h':
                usage(argv[0]);
                exit(EXIT_FAILURE);
            default:
                break;
        }
    }

    if ((!tcp_ip_addr) || (!tcp_ip_port)) {
        fprintf(
            stderr,
            "Please supply the address and port of the SBP data stream!\n"
        );
        exit(EXIT_FAILURE);
    }

    setup_socket();
    sbp_state_init(&s);

    /* Register a node and callback, and associate them with a specific message ID. */
    sbp_register_callback(
        &s,
        SBP_MSG_GPS_TIME,
        &sbp_gps_time_callback,
        NULL,
        &gps_time_node
    );
    sbp_register_callback(
        &s,
        SBP_MSG_POS_LLH,
        &sbp_pos_llh_callback,
        NULL,
        &pos_llh_node
    );
    sbp_register_callback(
        &s,
        SBP_MSG_BASELINE_NED,
        &sbp_baseline_ned_callback,
        NULL,
        &baseline_ned_node
    );
    sbp_register_callback(
        &s,
        SBP_MSG_VEL_NED,
        &sbp_vel_ned_callback,
        NULL,
        &vel_ned_node
    );
    sbp_register_callback(
        &s,
        SBP_MSG_DOPS,
        &sbp_dops_callback,
        NULL,
        &dops_node
    );

    while (1) {
        sbp_process(&s, &socket_read);

        fprintf(stdout, "\n\n\n\n");

        /* Print GPS time. */
        fprintf(stdout, "GPS Time:\n");
        fprintf(stdout, "\tWeek\t\t: %6d\n", (int)gps_time.wn);
        fprintf(stdout, "%6.2f", ((float)gps_time.tow) / 1e3);
        fprintf(stdout, "\n");

        /* Print absolute position. */
        fprintf(stdout, "Absolute Position:\n");
        fprintf(stdout, "%4.10lf", pos_llh.lat);
        fprintf(stdout, "%4.10lf", pos_llh.lon);
        fprintf(stdout, "%4.10lf", pos_llh.height);
        fprintf(stdout, "\tSatellites\t:     %02d\n", pos_llh.n_sats);
        fprintf(stdout, "\n");

        /* Print NED (North/East/Down) baseline (position vector from base to rover). */
        fprintf(stdout, "Baseline (mm):\n");
        fprintf(stdout, "\tNorth\t\t: %6d\n", (int)baseline_ned.n);
        fprintf(stdout, "\tEast\t\t: %6d\n", (int)baseline_ned.e);
        fprintf(stdout, "\tDown\t\t: %6d\n", (int)baseline_ned.d);
        fprintf(stdout, "\n");

        /* Print NED velocity. */
        fprintf(stdout, "Velocity (mm/s):\n");
        fprintf(stdout, "\tNorth\t\t: %6d\n", (int)vel_ned.n);
        fprintf(stdout, "\tEast\t\t: %6d\n", (int)vel_ned.e);
        fprintf(stdout, "\tDown\t\t: %6d\n", (int)vel_ned.d);
        fprintf(stdout, "\n");
    }

    close_socket();
    free(tcp_ip_addr);
    free(tcp_ip_port);
    return result;
}