Add TAI handling for EDI with TIST

1 files changed, 85 insertions, 0 deletions

diff --git a/src/ClockTAI.h b/src/ClockTAI.h
new file mode 100644
index 0000000..027e6db
--- /dev/null
+++ b/src/ClockTAI.h
@@ -0,0 +1,85 @@
+/*
+   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/>.
+*/
+
+/* The EDI output needs TAI clock, according to ETSI TS 102 693 Annex F
+ * "EDI Timestamps". This module sets the local CLOCK_TAI clock by
+ * setting the TAI-UTC offset using adjtimex.
+ *
+ * This functionality requires Linux 3.10 (30 Jun 2013) or newer */
+
+#ifndef __CLOCK_TAI_H_
+#define __CLOCK_TAI_H_
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <sstream>
+#include <time.h>
+
+// EDI needs to know UTC-TAI, but doesn't need the CLOCK_TAI to be set
+#define SUPPORT_SETTING_CLOCK_TAI 0
+
+/* Loads, parses and represents TAI-UTC offset information from the USNO bulletin */
+class ClockTAI {
+    public:
+        ClockTAI();
+
+        // Fetch the bulletin from the USNO website and return the current
+        // TAI-UTC offset.
+        // Throws runtime_error on failure.
+        int get_offset(void);
+
+#if SUPPORT_SETTING_CLOCK_TAI
+        // Update the local TAI clock according to the TAI-UTC offset
+        // return 0 on success
+        int update_local_tai_clock(int offset);
+#endif
+
+    private:
+        // leap seconds insertion bulletin is available at
+        const char* tai_data_url1 = "http://maia.usno.navy.mil/ser7/tai-utc.dat";
+        const char* tai_data_url2 = "http://toshi.nofs.navy.mil/ser7/tai-utc.dat";
+
+        int m_offset;
+        std::stringstream m_bulletin;
+        struct timespec m_bulletin_download_time;
+
+        // Load bulletin into m_bulletin, return 0 on success
+        int download_tai_utc_bulletin(const char* url);
+
+        // read TAI offset from m_bulletin
+        int parse_tai_offset(void);
+
+        // callback that receives data from cURL
+        size_t fill_bulletin(char *ptr, size_t size, size_t nmemb);
+
+        // static callback wrapper for cURL
+        static size_t fill_bulletin_cb(
+                char *ptr, size_t size, size_t nmemb, void *ctx);
+};
+
+#endif // __CLOCK_TAI_H_
+