cpp-json-lite

A simple json parser on C++

supports UTF-8 encoding

bash_test.sh to build test_cases, the unittest only contains regressions test

C++ Standard

C++ 11 or later is required.

Usage

Be careful when copying a JSON object, because when you copy A to B, A should no longer be used (like be moved, TODO: using move semantics, disable copy construction and assignment)

JSON A=B; 
A.add_pair("GOOD",B); // BOOM!!!! The node object inside has been deleted twice
```cpp
A.add_pair("GOOD",B.clone()); // Okay

// and never add itself
A.add_pair("Self",A); // BOOM
A.add_pair("Self",A.clone()); // Okay

Create or Clone

JSON json(std::string str); // it will jsonify the str.
JSON::clone(); // clone a json object

Visit

get int value by JSON::get_int();

int val=json.get_int();

get string value by JSON::get_str();

std::string str=json.get_str();

visit map by string index

JSON sub_json=json["servers"]["port"];
int port=sub_json.get_int();

visit array by number index

int val=json[0].get_int();

get list

std::vector<JSON> JSON::get_list() const;

get map

std::map<std::string, JSON> JSON::get_map() const;

Get elements count

// for map
size_t count() const;
// for list
size_t length() const;

to_string

std::string to_string(std::string indent);

Add elements

// for map
void add_pair(const std::string &str, JSON);
// for array
void push(JSON);

e.g.

    JSON json("{}");

    json.add_pair("port", JSON::val(8080));
    json.add_pair("server", JSON::val("localhost"));

    JSON arr_json("[]");
    arr_json.push(JSON::val("GOOD Boy"));
    arr_json.push(JSON::val(123));
    arr_json.push(json.clone());

Build json by value

static JSON val(int val);
static JSON val(const std::string &str);
static JSON map(const std::map<std::string, JSON> &table);
static JSON array(const std::vector<JSON> &vec);

example

    JSON json = JSON::map({
        {"port",JSON::val(123)},
        {"path",JSON::array({
            JSON::val(1),
            JSON::val("Hello World")
        })}
    });

Extend grammar

If you want to append some raw data (like pictures or some binary files), you can build your json as follows. (raw-length)$raw_contenst$

{
    "picture":(512)$the binary content of the picture$
}

here are some methods;

create raw object

static JSON raw(const std::vector<unsigned char> &vec);
static JSON raw(std::vector<unsigned char> &&vec);

get raw object

std::vector<unsigned char> &get_raw() const;

if you want to output the json without raw content you can call view(), view is similar to to_string, but it replaces the raw data with its length.

std::string view(std::string indent = "    ") const;

About the author

Htto Hu or 胡远韬 2021

HttoHu / cpp-json-lite