added new JsonBuffer class which will obsolete struct buffer

common/include/villas/json_buffer.hpp

@@ -0,0 +1,58 @@
+/** A simple buffer for encoding streamed JSON messages.
+ *
+ * @file
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017-2018, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLAScommon
+ *
+ * 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 <vector>
+
+#include <stdlib.h>
+
+#include <jansson.h>
+
+namespace villas {
+
+class Buffer : public std::vector<char> {
+
+public:
+	void append(const char *data, size_t len)
+	{
+		insert(end(), data, data + len);
+	}
+
+};
+
+class JsonBuffer : public Buffer
+{
+
+protected:
+	static int callback(const char *data, size_t len, void *ctx);
+
+public:
+	/** Encode JSON document /p j and append it to the buffer */
+	int encode(json_t *j);
+
+	/** Decode JSON document from the beginning of the buffer */
+	json_t * decode();
+};
+
+} // namespace villas

common/lib/CMakeLists.txt

@@ -24,6 +24,7 @@ add_library(villas-common SHARED
 	advio.c
     bitset.c
     buffer.c
+	json_buffer.cpp
 	compat.c
     crypt.c
     hash_table.c

common/lib/buffer.c

@@ -1,6 +1,5 @@
 /** A simple growing buffer.
  *
- * @file
  * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
  * @copyright 2017-2018, Institute for Automation of Complex Power Systems, EONERC
  * @license GNU General Public License (version 3)

common/lib/json_buffer.cpp

@@ -0,0 +1,56 @@
+/** A simple buffer for encoding streamed JSON messages.
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017-2018, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLAScommon
+ *
+ * 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 <villas/compat.h>
+#include <villas/json_buffer.hpp>
+
+using namespace villas;
+
+json_t * JsonBuffer::decode()
+{
+	json_t *j;
+	json_error_t err;
+
+	j = json_loadb(data(), size(), JSON_DISABLE_EOF_CHECK, &err);
+	if (!j)
+		return nullptr;
+
+	/* Remove decoded JSON document from beginning */
+	erase(begin(), begin() + err.position);
+
+	return j;
+}
+
+int JsonBuffer::encode(json_t *j)
+{
+	return json_dump_callback(j, callback, this, 0);
+}
+
+int JsonBuffer::callback(const char *data, size_t len, void *ctx)
+{
+	Buffer *b = static_cast<Buffer *>(ctx);
+
+	/* Append junk of JSON to buffer */
+	b->insert(b->end(), &data[0], &data[len]);
+
+	return 0;
+}

common/tests/CMakeLists.txt

@@ -25,6 +25,7 @@ add_executable(unit-tests-common
 	logging.cpp
 
 	advio.cpp
+	json_buffer.cpp
 	bitset.cpp
 	graph.cpp
 	hash_table.cpp

common/tests/json_buffer.cpp

@@ -0,0 +1,135 @@
+/** Unit tests for buffer
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017-2018, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLAScommon
+ *
+ * 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 <cstdlib>
+#include <ctime>
+
+#include <criterion/criterion.h>
+#include <jansson.h>
+
+#include <villas/json_buffer.hpp>
+
+using namespace villas;
+
+void init_logging();
+
+using villas::Buffer;
+
+TestSuite(buffer,
+	.description = "Buffer datastructure",
+	.init = init_logging
+);
+
+Test(json_buffer, decode)
+{
+	JsonBuffer buf;
+	json_t *j;
+	json_t *k;
+
+	const char *e = "{\"id\": \"5a786626-fbc6-4c04-98c2-48027e68c2fa\"}";
+	size_t len = strlen(e);
+
+	buf.insert(buf.begin(), e, e+len);
+
+	k = json_loads(e, 0, NULL);
+	cr_assert_not_null(k);
+
+	j = buf.decode();
+	cr_assert_not_null(j);
+	cr_assert(json_equal(j, k));
+}
+
+Test(json_buffer, encode)
+{
+	int ret;
+	JsonBuffer buf;
+	json_t *k;
+
+	const char *e = "{\"id\": \"5a786626-fbc6-4c04-98c2-48027e68c2fa\"}";
+
+	k = json_loads(e, 0, NULL);
+	cr_assert_not_null(k);
+
+	ret = buf.encode(k);
+	cr_assert_eq(ret, 0);
+
+	char *f = buf.data();
+	cr_assert_not_null(f);
+
+	cr_assert_str_eq(e, f);
+
+	json_decref(k);
+}
+
+Test(json_buffer, encode_decode)
+{
+	int ret;
+	JsonBuffer buf;
+	json_t *k;
+	json_t *j;
+
+	const char *e = "{\"id\": \"5a786626-fbc6-4c04-98c2-48027e68c2fa\"}";
+
+	k = json_loads(e, 0, NULL);
+	cr_assert_not_null(k);
+
+	ret = buf.encode(k);
+	cr_assert_eq(ret, 0);
+
+	j = buf.decode();
+	cr_assert_not_null(j);
+
+	cr_assert(json_equal(j, k));
+
+	json_decref(j);
+	json_decref(k);
+}
+
+Test(json_buffer, multiple)
+{
+	int ret;
+	const int N = 100;
+
+	JsonBuffer buf;
+	json_t *k[N];
+	json_t *j[N];
+
+	std::srand(std::time(nullptr));
+
+	for (int i = 0; i < N; i++) {
+		k[i] = json_pack("{ s: i }", "id", std::rand());
+		cr_assert_not_null(k[i]);
+
+		ret = buf.encode(k[i]);
+		cr_assert_eq(ret, 0);
+	}
+
+	for (int i = 0; i < N; i++) {
+		j[i] = buf.decode();
+		cr_assert_not_null(j[i]);
+
+		cr_assert(json_equal(k[i], j[i]));
+
+		json_decref(k[i]);
+		json_decref(j[i]);
+	}
+}