Added support for null value

Author: MaxCharlington

examples/test.json

@@ -3,6 +3,7 @@
     "title": "example glossary",
     "GlossDiv": {
       "title": "S",
+      "subtitle": null,
       "GlossList": {
         "GlossEntry": {
           "ID": "SGML",

include/json2cpp/json2cpp.hpp

@@ -88,6 +88,7 @@ template<typename CharType> struct data_variant
     std::uint64_t uint64_t_;
     double double_;
     std::basic_string_view<CharType> string_view_;
+    std::nullptr_t null_;
 
     constexpr explicit value_t() : empty_{} {}
     constexpr explicit value_t(monostate) : value_t() {}
@@ -99,9 +100,10 @@ template<typename CharType> struct data_variant
     constexpr explicit value_t(std::uint64_t i) : uint64_t_{ i } {}
     constexpr explicit value_t(double d) : double_{ d } {}
     constexpr explicit value_t(std::basic_string_view<CharType> s) : string_view_{ s } {}
+    constexpr explicit value_t(std::nullptr_t) : null_{} {}
   };
 
-  enum struct selected_type { empty, boolean, binary, array, object, integer, uinteger, floating_point, string };
+  enum struct selected_type { empty, boolean, binary, array, object, integer, uinteger, floating_point, string, nullish };
 
   value_t value{ monostate{} };
   selected_type selected{ selected_type::empty };
@@ -125,6 +127,8 @@ template<typename CharType> struct data_variant
   constexpr data_variant(double d) : value{ d }, selected{ selected_type::floating_point } {}
   // cppcheck-suppress noExplicitConstructor
   constexpr data_variant(std::basic_string_view<CharType> s) : value{ s }, selected{ selected_type::string } {}
+  // cppcheck-suppress noExplicitConstructor
+  constexpr data_variant(std::nullptr_t) : value{ nullptr }, selected{ selected_type::nullish } {}
 
   [[nodiscard]] constexpr bool is_boolean() const noexcept { return selected == selected_type::boolean; }
 
@@ -204,6 +208,8 @@ template<typename CharType> struct data_variant
       return nullptr;
     }
   }
+
+  [[nodiscard]] constexpr bool is_null() const noexcept { return selected == selected_type::nullish; }
 };
 
 template<typename CharType> struct basic_json
@@ -435,6 +441,12 @@ template<typename CharType> struct basic_json
       } else {
         throw std::runtime_error("Unexpected type: bool requested");
       }
+    } else if constexpr (std::is_same_v<Type, std::nullptr_t>) {
+      if (data.is_null()) {
+        return nullptr;
+      } else {
+        throw std::runtime_error("Unexpected type: null requested");
+      }
     } else {
       throw std::runtime_error("Unexpected type for get()");
     }
@@ -447,7 +459,7 @@ template<typename CharType> struct basic_json
   [[nodiscard]] constexpr bool is_structured() const noexcept { return is_object() || is_array(); }
   [[nodiscard]] constexpr bool is_number() const noexcept { return is_number_integer() || is_number_float(); }
   [[nodiscard]] constexpr bool is_number_integer() const noexcept { return is_number_signed() || is_number_unsigned(); }
-  [[nodiscard]] constexpr bool is_null() const noexcept { return data.selected == data_t::selected_type::empty; }
+  [[nodiscard]] constexpr bool is_null() const noexcept { return data.selected == data_t::selected_type::nullish; }
   [[nodiscard]] constexpr bool is_binary() const noexcept { return data.selected == data_t::selected_type::binary; }
 
   [[nodiscard]] constexpr bool is_number_signed() const noexcept

src/json2cpp.cpp

@@ -78,6 +78,8 @@ std::string compile(const nlohmann::json &value, std::size_t &obj_count, std::ve
     return fmt::format("bool{{{}}}", value.get<bool>());
   } else if (value.is_string()) {
     return fmt::format("string_view{{{}}}", json_string(value.get<std::string>()));
+  } else if (value.is_null()) {
+    return "std::nullptr_t{}";
   }
 
   return "unhandled";

src/schema_validator.cpp

@@ -24,7 +24,14 @@ SOFTWARE.
 
 #include <filesystem>
 #include <fstream>
+#ifdef __GNUC__
+  #pragma GCC diagnostic push
+  #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 #include <functional>
+#ifdef __GNUC__
+  #pragma GCC diagnostic pop
+#endif
 #include <iostream>
 
 #include <docopt/docopt.h>
@@ -140,6 +147,7 @@ template<typename JSON>
 void walk_internal(std::int64_t &int_sum,
   double &double_sum,
   std::size_t &string_sizes,
+  int &null_count,
   int &array_count,
   int &object_count,
   const JSON &obj)
@@ -150,15 +158,17 @@ void walk_internal(std::int64_t &int_sum,
     double_sum += obj.template get<double>();
   } else if (obj.is_string()) {
     string_sizes += obj.template get<std::string_view>().size();
+  } else if (obj.is_null()) {
+    ++null_count;
   } else if (obj.is_array()) {
     ++array_count;
     for (const auto &child : obj) {
-      walk_internal(int_sum, double_sum, string_sizes, array_count, object_count, child);
+      walk_internal(int_sum, double_sum, string_sizes, null_count, array_count, object_count, child);
     }
   } else if (obj.is_object()) {
     ++object_count;
     for (const auto &child : obj) {
-      walk_internal(int_sum, double_sum, string_sizes, array_count, object_count, child);
+      walk_internal(int_sum, double_sum, string_sizes, null_count, array_count, object_count, child);
     }
   }
 }
@@ -168,14 +178,15 @@ template<typename JSON> void walk(const JSON &objects)
   std::int64_t int_sum{};
   double double_sum{};
   std::size_t string_sizes{};
+  int null_count{};
   int array_count{};
   int object_count{};
 
   spdlog::info("Starting tree walk");
 
-  walk_internal(int_sum, double_sum, string_sizes, array_count, object_count, objects);
+  walk_internal(int_sum, double_sum, string_sizes, null_count, array_count, object_count, objects);
 
-  spdlog::info("{} {} {} {} {}", int_sum, double_sum, string_sizes, array_count, object_count);
+  spdlog::info("{} {} {} {} {} {}", int_sum, double_sum, string_sizes, null_count, array_count, object_count);
 }
 
 int main(int argc, const char **argv)

test/valijson_tests.cpp

@@ -1,7 +1,14 @@
 #include "allof_integers_and_numbers.schema.hpp"
 #include "array_doubles_10_20_30_40.hpp"
 #include "array_integers_10_20_30_40.hpp"
+#ifdef __GNUC__
+  #pragma GCC diagnostic push
+  #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
 #include <catch2/catch.hpp>
+#ifdef __GNUC__
+  #pragma GCC diagnostic pop
+#endif
 #include <json2cpp/json2cpp_adapter.hpp>
 #include <valijson/schema.hpp>
 #include <valijson/schema_parser.hpp>