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authorMatthias P. Braendli <matthias.braendli@mpb.li>2016-01-08 11:49:26 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2016-01-10 20:32:49 +0100
commit70c5ba0867945bb097f466262ce03470b690518f (patch)
treec7b14e7e5debdad25778d18559d42f5306289e67 /src/ClockTAI.cpp
parent3bcda54518c4914c1b934d7d12b7219d1ee7d941 (diff)
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Add TAI handling for EDI with TIST
Diffstat (limited to 'src/ClockTAI.cpp')
-rw-r--r--src/ClockTAI.cpp220
1 files changed, 220 insertions, 0 deletions
diff --git a/src/ClockTAI.cpp b/src/ClockTAI.cpp
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+++ b/src/ClockTAI.cpp
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+/*
+ Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+ 2011, 2012 Her Majesty the Queen in Right of Canada (Communications
+ Research Center Canada)
+
+ Copyright (C) 2016
+ Matthias P. Braendli, matthias.braendli@mpb.li
+
+ http://www.opendigitalradio.org
+ */
+/*
+ This file is part of ODR-DabMux.
+
+ ODR-DabMux is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as
+ published by the Free Software Foundation, either version 3 of the
+ License, or (at your option) any later version.
+
+ ODR-DabMux is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with ODR-DabMux. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "ClockTAI.h"
+
+#include <stdio.h>
+#include <errno.h>
+#include <sys/timex.h>
+#include <curl/curl.h>
+#include <string>
+#include <iostream>
+#include <algorithm>
+#include <regex>
+
+/* Last line from bulletin, example:
+ 2015 JUL 1 =JD 2457204.5 TAI-UTC= 36.0 S + (MJD - 41317.) X 0.0 S
+ */
+
+ClockTAI::ClockTAI()
+{
+ m_offset = 0;
+ m_bulletin_download_time.tv_nsec = 0;
+ m_bulletin_download_time.tv_sec = 0;
+}
+
+int ClockTAI::get_offset()
+{
+ struct timespec time_now;
+
+ int err = clock_gettime(CLOCK_REALTIME, &time_now);
+ if (err) {
+ throw std::runtime_error("ClockTAI::get_offset() clock_gettime failed");
+ }
+
+ if (time_now.tv_sec - m_bulletin_download_time.tv_sec >
+ 3600 * 24 * 31) {
+ // Refresh if it's older than one month. Leap seconds are
+ // announced several months in advance
+
+ if (download_tai_utc_bulletin(tai_data_url1) == 0) {
+ m_offset = parse_tai_offset();
+ }
+ else if (download_tai_utc_bulletin(tai_data_url2) == 0) {
+ m_offset = parse_tai_offset();
+ }
+ }
+
+ return m_offset;
+
+ throw std::runtime_error("Could not fetch TAI-UTC offset");
+}
+
+#if SUPPORT_SETTING_CLOCK_TAI
+int ClockTAI::update_local_tai_clock(int offset)
+{
+ struct timex timex_request;
+ timex_request.modes = ADJ_TAI;
+ timex_request.constant = offset;
+
+ int err = adjtimex(&timex_request);
+ if (err == -1) {
+ perror("adjtimex");
+ }
+
+ printf("adjtimex: %d, tai %d\n", err, timex_request.tai);
+
+ return err;
+}
+#endif
+
+int ClockTAI::parse_tai_offset()
+{
+ std::regex regex_offset("TAI-UTC= *([0-9.]+)");
+
+ int tai_utc_offset = 0;
+
+ int linecount = 0;
+
+ for (std::string line; std::getline(m_bulletin, line); ) {
+ linecount++;
+ auto words_begin =
+ std::sregex_token_iterator(
+ line.begin(), line.end(), regex_offset, 1);
+ auto words_end = std::sregex_token_iterator();
+
+ for (auto w = words_begin; w != words_end; ++w) {
+ std::string s(*w);
+ tai_utc_offset = std::atoi(s.c_str());
+ }
+
+ }
+
+ if (linecount == 0) {
+ throw std::runtime_error("No data in TAI bulletin");
+ }
+
+ // With the current evolution of the offset, we're probably going
+ // to reach 500 long after DAB gets replaced by another standard.
+ if (tai_utc_offset < 0 or tai_utc_offset > 500) {
+ std::stringstream ss;
+ ss << "TAI offset " << tai_utc_offset << " out of range";
+ throw std::range_error(ss.str());
+ }
+
+ return tai_utc_offset;
+}
+
+size_t ClockTAI::fill_bulletin(char *ptr, size_t size, size_t nmemb)
+{
+ size_t len = size * nmemb;
+ for (size_t i = 0; i < len; i++) {
+ m_bulletin << ptr[i];
+ }
+ return len;
+}
+
+size_t ClockTAI::fill_bulletin_cb(
+ char *ptr, size_t size, size_t nmemb, void *ctx)
+{
+ return ((ClockTAI*)ctx)->fill_bulletin(ptr, size, nmemb);
+}
+
+int ClockTAI::download_tai_utc_bulletin(const char* url)
+{
+ int r = 0;
+
+ CURL *curl;
+ CURLcode res;
+
+ curl = curl_easy_init();
+ if (curl) {
+ curl_easy_setopt(curl, CURLOPT_URL, url);
+ /* example.com is redirected, so we tell libcurl to follow redirection */
+ curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
+ curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, ClockTAI::fill_bulletin_cb);
+ curl_easy_setopt(curl, CURLOPT_WRITEDATA, this);
+
+ res = curl_easy_perform(curl);
+ if (res != CURLE_OK) {
+ fprintf(stderr, "curl_easy_perform() failed: %s\n",
+ curl_easy_strerror(res));
+
+ r = 1;
+ }
+ else {
+ // Save the download time of the bulletin
+ int err = clock_gettime(CLOCK_REALTIME, &m_bulletin_download_time);
+ if (err) {
+ perror("REALTIME clock_gettime failed");
+ r = 1;
+ }
+ }
+
+ /* always cleanup */
+ curl_easy_cleanup(curl);
+ }
+ return r;
+}
+
+#if 0
+// Example testing code
+void debug_tai_clk()
+{
+ struct timespec rt_clk;
+
+ int err = clock_gettime(CLOCK_REALTIME, &rt_clk);
+ if (err) {
+ perror("REALTIME clock_gettime failed");
+ }
+
+ struct timespec tai_clk;
+
+ err = clock_gettime(CLOCK_TAI, &tai_clk);
+ if (err) {
+ perror("TAI clock_gettime failed");
+ }
+
+ printf("RT - TAI = %ld\n", rt_clk.tv_sec - tai_clk.tv_sec);
+
+
+ struct timex timex_request;
+ timex_request.modes = 0; // Do not set anything
+
+ err = adjtimex(&timex_request);
+ if (err == -1) {
+ perror("adjtimex");
+ }
+
+ printf("adjtimex: %d, tai %d\n", err, timex_request.tai);
+}
+#endif
+