jujson

jujson is a lightweight, header-only C++11 library designed for parsing JSON. It provides a simple and efficient way to parse JSON strings into structured json_value objects, supporting various JSON data types including null, boolean, string, number, array, and object.

• Features
• Installation
• Usage
• Examples
• Acknowledgments
• License

Features

• Header-Only: No need to compile separate libraries; just include the header file.
• C++11 Compatible: Works with C++11 and later standards.
• Efficient Parsing: Designed to be fast and lightweight.
• Customizable: Easily extendable with custom traits and value types.

• JSON Value Types

jujson supports the following JSON value types:

• Null: JUSJON_JSON_VALUE_NULL
• Boolean: JUSJON_JSON_VALUE_TRUE, JUSJON_JSON_VALUE_FALSE
• String: JUSJON_JSON_VALUE_STRING
• Number: JUSJON_JSON_VALUE_NUMBER
• Array: JUSJON_JSON_VALUE_ARRAY
• Object: JUSJON_JSON_VALUE_OBJECT

JSON Traits

You can customize the JSON traits by defining your own traits class. The default traits are provided for char and wchar_t.

struct custom_json_traits {
    typedef char char_type;

    static constexpr char_type get_string_litteral_begin() noexcept { return '>'; } // default - "
    static constexpr char_type get_string_litteral_end() noexcept { return '<'; } // default - "
    static bool is_string_litteral_begin(char_type c) noexcept { return c == get_string_litteral_begin(); }
    static bool is_string_litteral_end(char_type c) noexcept { return c == get_string_litteral_end(); }
    // Define other traits as needed...
};

Error Handling

jujson provides error codes to help with debugging:

• jujson_ERROR_CODE_SUCCESS: Successful parsing.
• jujson_ERROR_CODE_UNEXPECTED: Unexpected character encountered.
• jujson_ERROR_CODE_EOF: End of file reached unexpectedly.

You can check the last error code using parser.get_last_error().

Installation

To use jujson, simply include the header file in your project:

#include "jujson.hpp"

Usage

jujson is designed to be a simple and (maybe)efficient JSON parsing library. It can be used in various applications where JSON data needs to be parsed and manipulated.

Examples

Basic

Here is a basic example of how to use jujson to parse a JSON string:

#include <iostream>
#include "jujson.hpp"

int main() {
    std::string jsonStr = R"({"name": "John", "age": 30, "isStudent": false, "courses": ["Math", "Science"]})";

    jujson::json_parser<std::string> parser(jsonStr);
    jujson::json_value<std::string> jsonObj = parser.parse_json_object_expected();

    if (jsonObj.is_valid()) {
        std::cout << "Parsed JSON: " << jsonObj.to_string() << '\n';
        return 0;
    } else {
        std::cerr << "Error parsing JSON: " << parser.get_last_error() << '\n';
        return 1;
    }

    return 0;
}

Accessing

#include <iostream>
#include "jujson.hpp"

int main() {
    std::string jsonStr = R"({"name": "John", "age": 30, "isStudent": false, "courses": ["Math", "Science"]})";

    jujson::json_parser<std::string> parser(jsonStr);
    jujson::json_value<std::string> jsonObj = parser.parse_json_object_expected();

    if (jsonObj.is_valid()) {
        // Accessing string value
        auto nameKV = jsonObj.find("name");
        if (nameKV != jsonObj.get_childs().end()) {
            std::cout << "Name: " << nameKV->value().data() << '\n';
        }

        // Accessing number value
        auto ageKV = jsonObj.find("age");
        if (ageKV != jsonObj.get_childs().end()) {
            std::cout << "Age: " << ageKV->value().data() << '\n';
        }

        // Accessing boolean value
        auto isStudentKV = jsonObj.find("isStudent");
        if (isStudentKV != jsonObj.get_childs().end()) {
            std::cout << "Is Student: " << isStudentKV->value().data() << '\n';
        }

        // Accessing array value
        auto coursesKV = jsonObj.find("courses");
        if (coursesKV != jsonObj.get_childs().end()) {
            for (const auto& courseKVs : coursesKV->value().get_childs()) {
                std::cout << "Course: " << courseKVs.data() << '\n';
            }
        }
        return 0;
    } else {
        std::cerr << parser.line() << ':' << parser.column() << ':' << " error parsing JSON: " << parser.get_last_error() << '\n';
        return 1;
    }
    return 0;
}

Custom Trait Type

#include <iostream>
#include "jujson.hpp"
struct custom_trait {
    public:
    typedef char char_type;

    public:
    [[nodiscard]] constexpr static char_type get_string_litteral_begin() noexcept   {return '<';}
    [[nodiscard]] constexpr static char_type get_string_litteral_end() noexcept     {return '>';}
    [[nodiscard]] static bool is_string_litteral_begin(char_type c) noexcept        {return c == get_string_litteral_begin();}
    [[nodiscard]] static bool is_string_litteral_end(char_type c) noexcept          {return c == get_string_litteral_end();}
    [[nodiscard]] constexpr static char_type get_array_begin() noexcept             {return '[';}
    [[nodiscard]] constexpr static char_type get_array_end() noexcept               {return ']';}
    // . . . - copy from default traits
};

int main() {
    std::string jsonStr = R"({<name>: <John>, <age>: 30, <isStudent>: false, <courses>: [<Math>, <Science>]})";

    jujson::json_parser<std::string> parser(jsonStr);
    jujson::json_value<std::string> jsonObj = parser.parse_json_object_expected();

    if (jsonObj.is_valid()) {
        std::cout << "Parsed JSON: " << jsonObj.to_string() << '\n';
        return 0;
    } else {
        std::cerr << "Error parsing JSON: " << parser.get_last_error() << '\n';
        return 1;
    }
    return 0;
}

Acknowledgments

• JSON Specification: https://www.json.org/json-en.html

License

This library is licensed under the MIT License. See the LICENSE file for more details.