formats: add specific json format for edgeFlex

include/villas/formats/json_edgeflex.hpp

+/** JSON serializtion for edgeFlex project.
+ *
+ * @author Manuel Pitz <manuel.pitz@eonerc.rwth-aachen.de>
+ * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program 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
+ * any later version.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+#pragma once
+
+#include <villas/formats/json.hpp>
+
+namespace villas {
+namespace node {
+
+class JsonEdgeflexFormat : public JsonFormat {
+
+protected:
+	int packSample(json_t **j, const struct sample *smp);
+	
+public:
+	using JsonFormat::JsonFormat;
+};
+
+} /* namespace node */
+} /* namespace villas */

lib/formats/CMakeLists.txt

@@ -62,6 +62,7 @@ endif()
 list(APPEND FORMAT_SRC
     column.cpp
     iotagent_ul.cpp
+    json_edgeflex.cpp
     json_kafka.cpp
     json_reserve.cpp
     json.cpp

lib/formats/json_edgeflex.cpp

+/** JSON serializtion for edgeFlex project.
+ *
+ * @author Manuel Pitz <manuel.pitz@eonerc.rwth-aachen.de>
+ * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program 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
+ * any later version.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+#include <cstring>
+
+#include <villas/timing.h>
+#include <villas/formats/json_edgeflex.hpp>
+
+using namespace villas::node;
+
+int JsonEdgeflexFormat::packSample(json_t **json_smp, const struct sample *smp)
+{
+	json_error_t err;
+	json_t *json_value;
+	json_t *json_created = nullptr;
+
+	if (smp->flags & (int) SampleFlags::HAS_TS_ORIGIN)
+		json_created = json_integer(time_to_double(&smp->ts.origin) * 1e3);
+
+
+	struct signal *sig = (struct signal *) vlist_at_safe(smp->signals, 0);
+	if (!sig)
+		return -1;
+
+
+	json_value = json_pack_ex(&err, 0, "{ s: f }",
+		"value", smp->data[0].f
+	);
+
+	if (json_created)
+		json_object_set_new(json_value, "created", json_created);
+
+	if (json_value == nullptr)
+		return -1;
+
+	*json_smp = json_value;
+
+	return 0;
+}
+
+static char n[] = "json.edgeflex";
+static char d[] = "EdgeFlex JSON format";
+static FormatPlugin<JsonEdgeflexFormat, n, d, (int) SampleFlags::HAS_TS_ORIGIN | (int) SampleFlags::HAS_SEQUENCE | (int) SampleFlags::HAS_DATA> p;