Add json/io.h/.cpp with write_json() and read_json()

VirtualRobot/CMakeLists.txt

@@ -353,6 +353,7 @@ SET(SOURCES
     Tools/Gravity.cpp
     
     Util/json/eigen_conversion.cpp
+    Util/json/io.cpp
     Util/xml/tinyxml2.cpp
     
     Visualization/ColorMap.cpp
@@ -575,6 +576,7 @@ SET(INCLUDES
     
     Util/json/eigen_conversion.h
     Util/json/eigen_conversion.hpp
+    Util/json/io.h
     Util/json/json.hpp
     Util/xml/tinyxml2.h
     

VirtualRobot/Util/json/io.cpp

+#include "io.h"
+
+#include <iostream>
+#include <fstream>
+
+
+namespace nlohmann
+{
+
+    json read_json(const std::string& filename)
+    {
+        std::ifstream ifs;
+        // Allow throwing std::ios_base::failure.
+        ifs.exceptions(std::ifstream::failbit | std::ifstream::badbit);
+        
+        ifs.open(filename);
+        json j;
+        ifs >> j;
+        return j;
+    }
+    
+    void write_json(const std::string& filename, const json& j,
+                    const int indent, const char indent_char)
+    {
+        std::ofstream ofs;
+        // Allow throwing std::ios_base::failure.
+        ofs.exceptions(std::ifstream::failbit | std::ifstream::badbit);
+        
+        ofs.open(filename);
+        ofs << j.dump(indent, indent_char);
+    }
+
+}
+
+

VirtualRobot/Util/json/io.h

+#pragma once
+
+#include "json.hpp"
+
+
+namespace nlohmann
+{
+
+    /**
+     * @brief Read a JSON document from the given file.
+     * 
+     * @param filename The name of the file to read from.
+     * @return The JSON document.
+     * 
+     * @throw std::ios_base::failure If IO access fails.
+     */
+    json read_json(const std::string& filename);
+    
+    
+    /**
+     * @brief Write a JSON document to the given file. 
+     * 
+     * @param j The JSON document.
+     * @param filename The name of the file to write to.
+     * @param indent See nlohmann::json::dump().
+     * @param indent_char See nlohmann::json::dump().
+     * 
+     * @throw std::ios_base::failure If IO access fails.
+     */
+    void write_json(const std::string& filename, const json& j,
+                    const int indent = -1, const char indent_char = ' ');
+
+
+}