Improve performance of JSON rendering (#6380)

unit_tests/util/json_render.cpp

@@ -0,0 +1,30 @@
+#include "util/json_container.hpp"
+#include "util/json_renderer.hpp"
+
+#include <boost/test/unit_test.hpp>
+
+#include <iostream>
+
+BOOST_AUTO_TEST_SUITE(json_renderer)
+
+using namespace osrm::util::json;
+
+BOOST_AUTO_TEST_CASE(number_truncating)
+{
+    std::string str;
+    Renderer<std::string> renderer(str);
+
+    // this number would have more than 10 decimals if not truncated
+    renderer(Number{42.9995999594999399299});
+    BOOST_CHECK_EQUAL(str, "42.999599959");
+}
+
+BOOST_AUTO_TEST_CASE(integer)
+{
+    std::string str;
+    Renderer<std::string> renderer(str);
+    renderer(Number{42.0});
+    BOOST_CHECK_EQUAL(str, "42");
+}
+
+BOOST_AUTO_TEST_SUITE_END()

unit_tests/util/string_util.cpp

@@ -12,13 +12,19 @@ using namespace osrm::util;
 BOOST_AUTO_TEST_CASE(json_escaping)
 {
     std::string input{"\b\\"};
-    std::string output{escape_JSON(input)};
+    std::string output;
+    EscapeJSONString(input, output);
 
+    BOOST_CHECK(RequiresJSONStringEscaping(input));
     BOOST_CHECK_EQUAL(output, "\\b\\\\");
 
     input = "Aleja \"Solidarnosci\"";
-    output = escape_JSON(input);
+    output.clear();
+    EscapeJSONString(input, output);
+    BOOST_CHECK(RequiresJSONStringEscaping(input));
     BOOST_CHECK_EQUAL(output, "Aleja \\\"Solidarnosci\\\"");
+
+    BOOST_CHECK(!RequiresJSONStringEscaping("Aleja Solidarnosci"));
 }
 
 BOOST_AUTO_TEST_CASE(print_int)