JSON tree node. More...

#include <pijson.h>

Public Types
enum	Type { Invalid , Null , Boolean , Number , String , Object , Array }
	Type of JSON node. More...

enum	PrintType { Compact , Tree }
	Formatting mode for JSON text output. More...

Public Member Functions
	PIJSON ()
	Constructs invalid PIJSON.

	PIJSON (const PIJSON &o)=default
	Copy constructor.

const PIString &	name () const
	Returns node name, or empty string for unnamed nodes.

const PIVector< PIJSON > &	array () const
	Returns array children, or an empty array when the node is not PIJSON::Array.

const PIMap< PIString, PIJSON > &	object () const
	Returns object members, or an empty map when the node is not PIJSON::Object.

const PIVariant &	value () const
	Returns scalar node value.

bool	toBool () const
	Returns scalar value as bool.

int	toInt () const
	Returns scalar value as integer.

double	toDouble () const
	Returns scalar value as floating-point number.

PIString	toString () const
	Returns scalar value as string.

Type	type () const
	Returns node type.

bool	isValid () const
	Returns whether the node is valid.

bool	isObject () const
	Returns whether the node is PIJSON::Object.

bool	isArray () const
	Returns whether the node is PIJSON::Array.

void	setValue (const PIVariant &v)
	Sets scalar value and updates node type for bool, numeric and string variants. More...

void	clear ()
	Clears node content and sets type to PIJSON::Invalid.

int	size () const
	Returns array length or object member count. Other node types return 0.

bool	contains (const PIString &key) const
	Returns whether an object node contains key key.

void	resize (int new_size)
	Converts node to array and resizes it. New entries become empty strings.

PIJSON &	operator= (const PIVariant &v)
	Synonym of setValue().

PIJSON &	operator= (const PIJSON &v)
	Copy assignment operator.

const PIJSON &	operator[] (int index) const
	Returns array element by index, or invalid PIJSON when the node is not an array.

PIJSON &	operator[] (int index)
	Converts node to array, grows it when needed and returns element by index.

PIJSON &	operator<< (const PIJSON &element)
	Converts node to array and appends another JSON node.

PIJSON &	operator<< (const PIVariant &value)
	Converts node to array and appends a scalar value.

PIJSON	operator[] (const PIString &key) const
	Returns object member by key, or invalid PIJSON when the node is not an object or the key is absent.

PIJSON &	operator[] (const PIString &key)
	Converts node to object and returns member by key, creating it when needed.

PIJSON	operator[] (const char *key) const
	Convenience overload for UTF-8 key access.

PIJSON &	operator[] (const char *key)
	Convenience overload for UTF-8 key access.

PIString	toJSON (PrintType print_type=Compact, bool mask_unicode=true) const
	Returns JSON text representation of the node tree.

Static Public Member Functions
static PIJSON	fromJSON (PIString str)
	Parses JSON text and returns the root node.

static PIJSON	newObject (const PIVariantMap &fields={})
	Creates an object node initialized from variant fields.

static PIJSON	newArray (const PIVariantVector &fields={})
	Creates an array node initialized from variant elements.

static PIJSON	newString (const PIString &v=PIString())
	Creates a string node.

template<typename T >
static PIJSON	serialize (const T &v)
	Serializes value v with the overload set from pijsonserialization.h. More...

template<typename T >
static T	deserialize (const PIJSON &json)
	Deserializes value of type `T` with the overload set from pijsonserialization.h. More...

Detailed Description

JSON tree node.

PIJSON class provides a tree structure for JSON data representation. Each element can be a value (with name), an array, or an object.

Synopsis

PIJSON tree

PIJSON creation

Mask/unmask

Examples

PIJSON json = PIJSON::fromJSON(
"["
"  true,"
"  10,"
"  {"
"    \"num\":1.E-2,"
"    \"str\":\"text\""
"  },"
"]");
piCout << json;
piCout << json.toJSON();

[
  true,
  10,
  {
    "num": 1.e-2,
    "str": "text"
  }
]
 
[true,10,{"num":1.e-2,"str":"text"}]

Разбор:

PIJSON json = PIJSON::fromJSON(
"["
"  true,"
"  10,"
"  {"
"    \"num\":1.E-2,"
"    \"str\":\"text\""
"  },"
"]");
piCout << "top-level:";
for (const auto & i: json.array())
    piCout << i.value();
piCout << "[2][\"str\"]:";
piCout << json[2]["str"].toString();

top-level:
PIVariant(Bool, 1)
PIVariant(String, 10)
PIVariant(Invalid)
[2]["str"]:
text

Создание:
Простой массив

PIJSON json;
json[0] = -1;
json[1] = "text";
json[3] = false;
piCout << json.toJSON();

[-1,"text","",false]

Массив объектов

struct {
    PIString name;
    PIString surname;
    PIString email;
} persons[] = {
    {"Ivan", "Ivanov", "ivan@pip.ru"},
    {"Igor", "Igorevich", "igor@pip.ru"},
    {"Andrey", "Andreevich", "andrey@pip.ru"}
};
PIJSON obj;
PIJSON json;
int index = 0;
for (const auto & p: persons) {
    obj["index"] = index++;
    obj["name"] = p.name;
    obj["surname"] = p.surname;
    obj["email"] = p.email;
    json << obj;
}
piCout << json;

[
  {
    "name": "Ivan",
    "email": "ivan@pip.ru",
    "index": 0,
    "surname": "Ivanov"
  },
  {
    "name": "Igor",
    "email": "igor@pip.ru",
    "index": 1,
    "surname": "Igorevich"
  },
  {
    "name": "Andrey",
    "email": "andrey@pip.ru",
    "index": 2,
    "surname": "Andreevich"
  }
]

Member Enumeration Documentation

◆ Type

enum PIJSON::Type

Type of JSON node.

Enumerator
Invalid	Invalid type
Null	Without value, null
Boolean	Boolean, true or false
Number	Integer or floating-point number
String	Text
Object	Object, {}
Array	Array, []

◆ PrintType

enum PIJSON::PrintType

Formatting mode for JSON text output.

Enumerator
Compact	Without spaces, minimum size
Tree	With spaces and new-lines, human-readable

Member Function Documentation

◆ setValue()

void PIJSON::setValue ( const PIVariant & v )

Sets scalar value and updates node type for bool, numeric and string variants.

If "v" type is boolean set type to PIJSON::Boolean.
If "v" type is any numeric set type to PIJSON::Number.
If "v" type is string set type to PIJSON::String.
In case of any other type set element type to PIJSON::Invalid.

◆ serialize()

template<typename T >

PIJSON PIJSON::serialize ( const T & v )

static

Serializes value v with the overload set from pijsonserialization.h.

Convenience wrapper around piSerializeJSON().

◆ deserialize()