Added ARDUINOJSON_ENABLE_NAN to enable NaN in JSON (closes #973)

CHANGELOG.md

@@ -7,6 +7,7 @@ HEAD
 * Fixed `deserializeJson()` silently accepting a `Stream*` (issue #978)
 * Fixed invalid result from `operator|` (issue #981)
 * Made `deserializeJson()` more picky about trailing characters (issue #980)
+* Added `ARDUINOJSON_ENABLE_NAN` to enable NaN in JSON (issue #973)
 
 > ### BREAKING CHANGE
 > 

src/ArduinoJson/Configuration.hpp

@@ -135,6 +135,11 @@
 #define ARDUINOJSON_DECODE_UNICODE 0
 #endif
 
+// Support NaN in JSON
+#ifndef ARDUINOJSON_ENABLE_NAN
+#define ARDUINOJSON_ENABLE_NAN 1
+#endif
+
 // Control the exponentiation threshold for big numbers
 // CAUTION: cannot be more that 1e9 !!!!
 #ifndef ARDUINOJSON_POSITIVE_EXPONENTIATION_THRESHOLD

src/ArduinoJson/Json/TextFormatter.hpp

@@ -52,7 +52,7 @@ class TextFormatter {
 
   template <typename T>
   void writeFloat(T value) {
-    if (isnan(value)) return writeRaw("NaN");
+    if (isnan(value)) return writeRaw(ARDUINOJSON_ENABLE_NAN ? "NaN" : "null");
 
     if (value < 0.0) {
       writeRaw('-');

src/ArduinoJson/Namespace.hpp

@@ -15,9 +15,12 @@
 #define ARDUINOJSON_CONCAT8(A, B, C, D, E, F, G, H)    \
   ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT4(A, B, C, D), \
                       ARDUINOJSON_CONCAT4(E, F, G, H))
+#define ARDUINOJSON_CONCAT9(A, B, C, D, E, F, G, H, I) \
+  ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT4(A, B, C, D), \
+                      ARDUINOJSON_CONCAT4(E, F, G, ARDUINOJSON_CONCAT2(H, I)))
 
 #define ARDUINOJSON_NAMESPACE                                                  \
-  ARDUINOJSON_CONCAT8(ArduinoJson, ARDUINOJSON_VERSION_MAJOR,                  \
+  ARDUINOJSON_CONCAT9(ArduinoJson, ARDUINOJSON_VERSION_MAJOR,                  \
                       ARDUINOJSON_VERSION_MINOR, ARDUINOJSON_VERSION_REVISION, \
                       _, ARDUINOJSON_USE_LONG_LONG, ARDUINOJSON_USE_DOUBLE,    \
-                      ARDUINOJSON_DECODE_UNICODE)
+                      ARDUINOJSON_DECODE_UNICODE, ARDUINOJSON_ENABLE_NAN)

src/ArduinoJson/Numbers/parseNumber.hpp

@@ -71,8 +71,9 @@ inline ParsedNumber<TFloat, TUInt> parseNumber(const char *s) {
       s++;
       break;
   }
-
+#if ARDUINOJSON_ENABLE_NAN
   if (*s == 'n' || *s == 'N') return traits::nan();
+#endif
   if (*s == 'i' || *s == 'I')
     return is_negative ? -traits::inf() : traits::inf();
   if (!isdigit(*s) && *s != '.') return return_type();

test/MixedConfiguration/CMakeLists.txt

@@ -12,6 +12,8 @@ add_executable(MixedConfigurationTests
 	use_double_1.cpp
 	use_long_long_0.cpp
 	use_long_long_1.cpp
+	enable_nan_0.cpp
+	enable_nan_1.cpp
 )
 
 target_link_libraries(MixedConfigurationTests catch)

test/MixedConfiguration/enable_nan_0.cpp

@@ -0,0 +1,25 @@
+#define ARDUINOJSON_ENABLE_NAN 0
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+#include <limits>
+
+TEST_CASE("ARDUINOJSON_ENABLE_NAN == 0") {
+  DynamicJsonDocument doc(4096);
+  JsonObject root = doc.to<JsonObject>();
+
+  SECTION("serializeJson()") {
+    root["X"] = std::numeric_limits<double>::signaling_NaN();
+
+    std::string json;
+    serializeJson(doc, json);
+
+    REQUIRE(json == "{\"X\":null}");
+  }
+
+  SECTION("deserializeJson()") {
+    auto err = deserializeJson(doc, "{\"X\":NaN}");
+
+    REQUIRE(err == DeserializationError::InvalidInput);
+  }
+}

test/MixedConfiguration/enable_nan_1.cpp

@@ -0,0 +1,31 @@
+#define ARDUINOJSON_ENABLE_NAN 1
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+#include <limits>
+
+namespace my {
+using ARDUINOJSON_NAMESPACE::isnan;
+}  // namespace my
+
+TEST_CASE("ARDUINOJSON_ENABLE_NAN == 1") {
+  DynamicJsonDocument doc(4096);
+  JsonObject root = doc.to<JsonObject>();
+
+  SECTION("serializeJson()") {
+    root["X"] = std::numeric_limits<double>::signaling_NaN();
+
+    std::string json;
+    serializeJson(doc, json);
+
+    REQUIRE(json == "{\"X\":NaN}");
+  }
+
+  SECTION("deserializeJson()") {
+    auto err = deserializeJson(doc, "{\"X\":NaN}");
+    float x = doc["X"];
+
+    REQUIRE(err == DeserializationError::Ok);
+    REQUIRE(my::isnan(x));
+  }
+}