Fix round-trip issue in float serialization using scientific notation (…

…#439)
fktn-k · Dec 9, 2024 · a5e73da · a5e73da
1 parent d049cad
commit a5e73da
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Showing 3 changed files with 10 additions and 8 deletions.
diff --git a/include/fkYAML/detail/conversions/to_string.hpp b/include/fkYAML/detail/conversions/to_string.hpp
@@ -79,10 +79,10 @@ inline enable_if_t<std::is_floating_point<FloatType>::value> to_string(FloatType
     oss << v;
     s = oss.str();
 
-    // If `f` is actually an integer, ".0" must be appended. The result would cause roundtrip issue otherwise.
-    // https://github.com/fktn-k/fkYAML/issues/405
-    const FloatType diff = v - std::floor(v);
-    if (diff < std::numeric_limits<FloatType>::min()) {
+    // If `v` is actually an integer and no scientific notation is used for serialization, ".0" must be appended.
+    // The result would cause a roundtrip issue otherwise. https://github.com/fktn-k/fkYAML/issues/405
+    const std::size_t pos = s.find_first_of(".e");
+    if (pos == std::string::npos) {
         s += ".0";
     }
 }

diff --git a/single_include/fkYAML/node.hpp b/single_include/fkYAML/node.hpp
@@ -10341,10 +10341,10 @@ inline enable_if_t<std::is_floating_point<FloatType>::value> to_string(FloatType
     oss << v;
     s = oss.str();
 
-    // If `f` is actually an integer, ".0" must be appended. The result would cause roundtrip issue otherwise.
-    // https://github.com/fktn-k/fkYAML/issues/405
-    const FloatType diff = v - std::floor(v);
-    if (diff < std::numeric_limits<FloatType>::min()) {
+    // If `v` is actually an integer and no scientific notation is used for serialization, ".0" must be appended.
+    // The result would cause a roundtrip issue otherwise. https://github.com/fktn-k/fkYAML/issues/405
+    const std::size_t pos = s.find_first_of(".e");
+    if (pos == std::string::npos) {
         s += ".0";
     }
 }

diff --git a/test/unit_test/test_serializer_class.cpp b/test/unit_test/test_serializer_class.cpp
@@ -60,6 +60,8 @@ TEST_CASE("SerializeClassTest_FloatNode", "[SerializeClassTest]") {
         node_str_pair_t(2.10, "2.1"),
         node_str_pair_t(3.14, "3.14"),
         node_str_pair_t(-53.97, "-53.97"),
+        node_str_pair_t(23000000.0, "2.3e+07"),
+        node_str_pair_t(-23000000.0, "-2.3e+07"),
         node_str_pair_t(std::numeric_limits<fkyaml::node::float_number_type>::infinity(), ".inf"),
         node_str_pair_t(-1 * std::numeric_limits<fkyaml::node::float_number_type>::infinity(), "-.inf"),
         node_str_pair_t(std::nan(""), ".nan"));