1 #pragma once
2
3 #include <array> // array
4 #include <ciso646> // and
5 #include <cstddef> // size_t
6 #include <cstdint> // uint8_t
7 #include <string> // string
8
9 namespace nlohmann
10 {
11 namespace detail
12 {
13 ///////////////////////////
14 // JSON type enumeration //
15 ///////////////////////////
16
17 /*!
18 @brief the JSON type enumeration
19
20 This enumeration collects the different JSON types. It is internally used to
21 distinguish the stored values, and the functions @ref basic_json::is_null(),
22 @ref basic_json::is_object(), @ref basic_json::is_array(),
23 @ref basic_json::is_string(), @ref basic_json::is_boolean(),
24 @ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
25 @ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
26 @ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
27 @ref basic_json::is_structured() rely on it.
28
29 @note There are three enumeration entries (number_integer, number_unsigned, and
30 number_float), because the library distinguishes these three types for numbers:
31 @ref basic_json::number_unsigned_t is used for unsigned integers,
32 @ref basic_json::number_integer_t is used for signed integers, and
33 @ref basic_json::number_float_t is used for floating-point numbers or to
34 approximate integers which do not fit in the limits of their respective type.
35
36 @sa @ref basic_json::basic_json(const value_t value_type) -- create a JSON
37 value with the default value for a given type
38
39 @since version 1.0.0
40 */
41 enum class value_t : std::uint8_t
42 {
43 null, ///< null value
44 object, ///< object (unordered set of name/value pairs)
45 array, ///< array (ordered collection of values)
46 string, ///< string value
47 boolean, ///< boolean value
48 number_integer, ///< number value (signed integer)
49 number_unsigned, ///< number value (unsigned integer)
50 number_float, ///< number value (floating-point)
51 discarded ///< discarded by the the parser callback function
52 };
53
54 /*!
55 @brief comparison operator for JSON types
56
57 Returns an ordering that is similar to Python:
58 - order: null < boolean < number < object < array < string
59 - furthermore, each type is not smaller than itself
60 - discarded values are not comparable
61
62 @since version 1.0.0
63 */
operator <(const value_t lhs,const value_t rhs)64 inline bool operator<(const value_t lhs, const value_t rhs) noexcept
65 {
66 static constexpr std::array<std::uint8_t, 8> order = {{
67 0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
68 1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */
69 }
70 };
71
72 const auto l_index = static_cast<std::size_t>(lhs);
73 const auto r_index = static_cast<std::size_t>(rhs);
74 return l_index < order.size() and r_index < order.size() and order[l_index] < order[r_index];
75 }
76 } // namespace detail
77 } // namespace nlohmann
78