feat: standalone C/C++ UDPS client library
Consuming a UDPStreamer feed so far meant either linking MARTe2 (UDPSClient) or writing Go (Common/Client/go/udpsprotocol). Common/Client/c fills the gap for plain C/C++ integrators: two files depending on nothing but libc and BSD sockets, covering the whole receive path — CONNECT, fragment reassembly, CONFIG/DATA decoding with dequantisation, keepalives and silence-triggered reconnect. No threads are spawned; udps_client_poll() does all the work and runs every callback, so it drops into an existing event loop unsynchronised. Verified against run_udp_producer.sh at 1 Msps: unicast (120 MiB, no loss) and multicast with 12-fragment cycles (116k datagrams, no loss). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Martino Ferrari
co-authored by
Claude Opus 4.6
Claude Opus 4.6
parent
e03c60db25
commit
7c5eb31a52
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/**
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* @file udps_dump.c
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* @brief Example UDPS client: connects to a UDPStreamer and prints what arrives.
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*
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* Build with the Makefile in the parent directory, then for a unicast stream:
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*
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* ./udps_dump --host 127.0.0.1 --port 44500
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*
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* or, for a multicast one:
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*
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* ./udps_dump --host 127.0.0.1 --port 44500 \
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* --multicast 239.0.0.1 --iface 127.0.0.1
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*
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* Ctrl-C prints a summary of what was received.
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*/
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#define _POSIX_C_SOURCE 200809L
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#include "udps_client.h"
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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static volatile sig_atomic_t g_stop = 0;
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static void on_sigint(int sig) {
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(void)sig;
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g_stop = 1;
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}
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typedef struct {
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double print_interval; /**< Seconds between frame printouts. */
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double last_print;
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uint64_t frames;
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uint64_t max_frames;
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} dump_state_t;
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static double now_wall(void) {
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struct timespec ts;
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clock_gettime(CLOCK_REALTIME, &ts);
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return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
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}
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static const char *time_mode_name(uint8_t m) {
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switch (m) {
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case UDPS_TIME_PACKET: return "packet";
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case UDPS_TIME_FULL_ARRAY: return "full-array";
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case UDPS_TIME_FIRST_SAMPLE: return "first-sample";
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case UDPS_TIME_LAST_SAMPLE: return "last-sample";
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default: return "?";
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}
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}
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static const char *publish_mode_name(uint8_t m) {
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switch (m) {
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case UDPS_PUBLISH_STRICT: return "strict";
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case UDPS_PUBLISH_ACCUMULATE: return "accumulate";
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case UDPS_PUBLISH_DECIMATE: return "decimate";
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default: return "?";
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}
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}
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static void on_config(const udps_signal_t *sigs, uint32_t n, uint8_t mode,
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void *user) {
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uint32_t i;
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(void)user;
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printf("\nCONFIG: %u signal(s), publish mode %s\n", (unsigned)n,
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publish_mode_name(mode));
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printf(" %-3s %-24s %-8s %-10s %-8s %-10s %s\n", "#", "name", "type",
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"shape", "unit", "rate[Hz]", "time-mode");
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for (i = 0u; i < n; i++) {
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char shape[32];
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const udps_signal_t *s = &sigs[i];
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if (s->num_cols > 1u) {
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snprintf(shape, sizeof shape, "%ux%u", (unsigned)s->num_rows,
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(unsigned)s->num_cols);
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} else {
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snprintf(shape, sizeof shape, "%u",
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(unsigned)udps_signal_num_elements(s));
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}
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printf(" %-3u %-24s %-8s %-10s %-8s %-10.6g %s%s\n", (unsigned)i,
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s->name, udps_type_name(s->type_code), shape,
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(s->unit[0] != '\0') ? s->unit : "-", s->sampling_rate,
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time_mode_name(s->time_mode),
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(s->quant_type != UDPS_QUANT_NONE) ? " (quantised)" : "");
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}
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fflush(stdout);
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}
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static void on_data(const udps_frame_t *f, void *user) {
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dump_state_t *st = (dump_state_t *)user;
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uint32_t i;
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double now;
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st->frames++;
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now = now_wall();
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if ((now - st->last_print) < st->print_interval) {
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return; /* Streams run far faster than a terminal can be read. */
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}
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st->last_print = now;
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printf("\nframe #%lu t=%.6f samples=%u (%lu frames so far)\n",
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(unsigned long)f->counter, f->recv_time, (unsigned)f->num_samples,
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(unsigned long)st->frames);
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for (i = 0u; i < f->num_signals; i++) {
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const double *v = f->values[i].values;
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uint32_t cnt = f->values[i].count;
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double lo, hi;
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uint32_t k;
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if (cnt == 0u) {
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continue;
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}
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lo = hi = v[0];
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for (k = 1u; k < cnt; k++) {
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if (v[k] < lo) {
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lo = v[k];
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}
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if (v[k] > hi) {
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hi = v[k];
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}
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}
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printf(" %-24s n=%-6u first=%-12.6g last=%-12.6g min=%-12.6g max=%-12.6g %s\n",
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f->signals[i].name, (unsigned)cnt, v[0], v[cnt - 1u], lo, hi,
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f->signals[i].unit);
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}
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fflush(stdout);
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}
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static void on_event(udps_event_t ev, const char *detail, void *user) {
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(void)user;
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switch (ev) {
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case UDPS_EVENT_CONNECTED:
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printf("[connected to %s]\n", detail ? detail : "");
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break;
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case UDPS_EVENT_DISCONNECTED:
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printf("[disconnected: %s]\n", detail ? detail : "");
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break;
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case UDPS_EVENT_ERROR:
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fprintf(stderr, "[error] %s\n", detail ? detail : "");
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break;
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default:
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break;
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}
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fflush(stdout);
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}
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static void usage(const char *argv0) {
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printf("Usage: %s --host ADDR --port N [options]\n"
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"\n"
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" --host ADDR server address (default 127.0.0.1)\n"
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" --port N server UDP port, or TCP control port in multicast\n"
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" mode (default 44500)\n"
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" --multicast GROUP join GROUP for data instead of unicast\n"
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" --iface ADDR local interface address for the multicast join\n"
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" --data-port N multicast data port (default: --port + 1)\n"
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" --silence SEC reconnect after SEC without data (default 1, 0 off)\n"
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" --interval SEC seconds between printouts (default 1)\n"
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" --frames N exit after N frames (default: run until Ctrl-C)\n"
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" --help this text\n",
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argv0);
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}
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int main(int argc, char **argv) {
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udps_client_config_t cfg;
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udps_client_t *cli;
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dump_state_t st;
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udps_stats_t stats;
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struct sigaction sa;
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const char *host = "127.0.0.1";
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int i;
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udps_client_config_init(&cfg);
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cfg.server_port = 44500u;
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memset(&st, 0, sizeof st);
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st.print_interval = 1.0;
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for (i = 1; i < argc; i++) {
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const char *a = argv[i];
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const char *next = (i + 1 < argc) ? argv[i + 1] : NULL;
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if (strcmp(a, "--help") == 0) {
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usage(argv[0]);
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return 0;
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}
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if (next == NULL) {
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fprintf(stderr, "missing value for %s\n", a);
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return 2;
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}
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if (strcmp(a, "--host") == 0) {
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host = next;
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} else if (strcmp(a, "--port") == 0) {
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cfg.server_port = (uint16_t)atoi(next);
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} else if (strcmp(a, "--multicast") == 0) {
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cfg.multicast_group = next;
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} else if (strcmp(a, "--iface") == 0) {
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cfg.interface_addr = next;
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} else if (strcmp(a, "--data-port") == 0) {
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cfg.data_port = (uint16_t)atoi(next);
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} else if (strcmp(a, "--silence") == 0) {
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cfg.silence_timeout_s = atof(next);
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} else if (strcmp(a, "--interval") == 0) {
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st.print_interval = atof(next);
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} else if (strcmp(a, "--frames") == 0) {
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st.max_frames = (uint64_t)strtoull(next, NULL, 10);
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} else {
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fprintf(stderr, "unknown option %s\n", a);
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usage(argv[0]);
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return 2;
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}
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i++;
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}
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cfg.server_addr = host;
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cli = udps_client_create(&cfg);
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if (cli == NULL) {
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fprintf(stderr, "could not create client for %s:%u\n", host,
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(unsigned)cfg.server_port);
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return 1;
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}
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udps_client_set_callbacks(cli, on_config, on_data, on_event, &st);
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memset(&sa, 0, sizeof sa);
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sa.sa_handler = on_sigint;
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(void)sigaction(SIGINT, &sa, NULL);
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(void)sigaction(SIGTERM, &sa, NULL);
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printf("listening to %s:%u%s%s ... (Ctrl-C to stop)\n", host,
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(unsigned)cfg.server_port,
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cfg.multicast_group ? " via multicast " : "",
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cfg.multicast_group ? cfg.multicast_group : "");
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while (!g_stop && (st.max_frames == 0u || st.frames < st.max_frames)) {
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/* All the work — connecting, receiving, decoding, reconnecting — and
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* every callback happens inside this call. */
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(void)udps_client_poll(cli, 200);
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}
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udps_client_stats(cli, &stats);
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printf("\n--- summary ---\n"
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"packets %lu\n"
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"bytes %.1f MiB\n"
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"frames %lu\n"
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"configs %lu\n"
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"gaps %lu (datagrams lost)\n"
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"dropped %lu (fragments)\n"
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"reconnects %lu\n",
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(unsigned long)stats.packets_received,
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(double)stats.bytes_received / (1024.0 * 1024.0),
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(unsigned long)stats.frames_delivered,
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(unsigned long)stats.config_updates,
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(unsigned long)stats.counter_gaps,
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(unsigned long)stats.fragments_dropped,
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(unsigned long)stats.reconnects);
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udps_client_destroy(cli);
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return 0;
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}
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