Refactor JSON parsing

src/ProcessManager.cpp

@@ -3,7 +3,6 @@
 #include <chrono>
 #include <unistd.h>
 #include <stdexcept>
-#include <boost/property_tree/json_parser.hpp>
 #include <boost/thread.hpp>
 #include <iostream>
 #include <memory>
@@ -84,7 +83,7 @@ void ProcessManager::write_h5(WriterManager& manager, const H5Format& format, Ri
     exit(0);
 }
 
-void ProcessManager::receive_zmq(WriterManager& manager, RingBuffer& ring_buffer, 
+void ProcessManager::receive_zmq(WriterManager& manager, RingBuffer& ring_buffer, const H5Format& format,
     const string& connect_address, int n_io_threads, int receive_timeout)
 {
     zmq::context_t context(n_io_threads);
@@ -103,29 +102,8 @@ void ProcessManager::receive_zmq(WriterManager& manager, RingBuffer& ring_buffer
             continue;
         }
 
-        // Parse JSON header.
-        auto frame_metadata = make_shared<FrameMetadata>();
-
-        frame_metadata->header_string = string(static_cast<char*>(message_header.data()), message_header.size());
-        
-        stringstream header_stream;
-        header_stream << frame_metadata->header_string << endl;
-
-        pt::read_json(header_stream, json_header);
-
-        // Extract data from message header.
-        frame_metadata->frame_index = json_header.get<uint64_t>("frame");
-
-        uint8_t index = 0;
-        for (const auto& item : json_header.get_child("shape")) {
-            frame_metadata->frame_shape[index] = item.second.get_value<size_t>();
-            ++index;
-        }
-
-        // Array 1.0 specified little endian as the default encoding.
-        frame_metadata->endianness = json_header.get("endianness", "little");
-
-        frame_metadata->type = json_header.get<string>("type");
+        auto header_string = string(static_cast<char*>(message_header.data()), message_header.size());
+        auto frame_metadata = read_json_header(json_header, header_string, format.get_header_value_type());
 
         // Get the message data.
         if (!receiver.recv(&message_data)) {
@@ -160,6 +138,73 @@ void ProcessManager::receive_zmq(WriterManager& manager, RingBuffer& ring_buffer
     #endif
 }
 
+boost::any get_value_from_json(const pt::ptree& json_header, const string& value_name, const HEADER_DATA_TYPE data_type)
+{
+    switch(data_type) {
+        case UINT8 : 
+            return json_header.get<uint8_t>(value_name);
+        case UINT16 : 
+            return json_header.get<uint16_t>(value_name);
+        case UINT32 : 
+            return json_header.get<uint32_t>(value_name);
+        case UINT64 : 
+            return json_header.get<uint64_t>(value_name);
+        case INT8 : 
+            return json_header.get<int8_t>(value_name);
+        case INT16 : 
+            return json_header.get<int16_t>(value_name);
+        case INT32 : 
+            return json_header.get<int32_t>(value_name);
+        case INT64 : 
+            return json_header.get<int64_t>(value_name);
+        case FLOAT32 :
+            return json_header.get<float>(value_name);
+        case FLOAT64 :
+            return json_header.get<double>(value_name);
+        default:
+            stringstream error_message;
+            error_message << "[ProcessManager::get_value_from_json] Unknown value type for header value " << value_name << endl;
+
+            throw runtime_error(error_message.str());
+    }
+}
+
+shared_ptr<FrameMetadata> ProcessManager::read_json_header(pt::ptree& json_header, 
+    const string& header, const map<string, HEADER_DATA_TYPE>& header_data_type)
+{   
+    stringstream header_stream;
+    header_stream << header << endl;
+    pt::read_json(header_stream, json_header);
+
+    auto header_data = make_shared<FrameMetadata>();
+
+    header_data->frame_index = json_header.get<uint64_t>("frame");
+
+    uint8_t index = 0;
+    for (const auto& item : json_header.get_child("shape")) {
+        header_data->frame_shape[index] = item.second.get_value<size_t>();
+        ++index;
+    }
+
+    // Array 1.0 specified little endian as the default encoding.
+    header_data->endianness = json_header.get("endianness", "little");
+
+    header_data->type = json_header.get<string>("type");
+
+    for (const auto& value_mapping : header_data_type) {
+        
+        const auto& name = value_mapping.first;
+        const auto& data_type = value_mapping.second;
+        const boost::any& value = get_value_from_json(json_header, name, data_type);
+
+        header_data->header_values.insert(
+            {name, value}
+        );
+    }
+
+    return header_data;
+}
+
 void ProcessManager::run_writer(WriterManager& manager, const H5Format& format, 
     const string& connect_address, uint16_t rest_port)
 {
@@ -179,7 +224,7 @@ void ProcessManager::run_writer(WriterManager& manager, const H5Format& format,
         cout << endl;
     #endif
 
-    boost::thread receiver_thread(receive_zmq, boost::ref(manager), boost::ref(ring_buffer), connect_address, n_io_threads, receive_timeout);
+    boost::thread receiver_thread(receive_zmq, boost::ref(manager), boost::ref(ring_buffer), boost::ref(format), connect_address, n_io_threads, receive_timeout);
     boost::thread writer_thread(write_h5, boost::ref(manager), boost::ref(format), boost::ref(ring_buffer));
 
     RestApi::start_rest_api(manager, rest_port);