cJSON Library

Introduction

This is a c library for interfacing with JSON formatted data. It is only optimized for interfacing operations such as parsing and serialization (not yet implemented). There is no efficient dictionary access such as a hash map implemented for dictionaries.

Constraints

The default maximum nesting depth of cJSON structures that will be handled by the parser is 255. This can be changed by either modifying the type definition for cJSON_depth_t or manually setting a limit by changing the CJSON_MAX_DEPTH macro in the cJSON_Constants file.

JSON Object Data Storage

Object storage is based on the cJSON_Generic_t struct which contains type information as well as a pointer to the underlying object. It is defined as follows in the cJSON_Types.h file:

typedef struct cJSON_Generic
{
    cJSON_ContainerType_t type;
    void *dataContainer;
} cJSON_Generic_t;

Structural types / JSON "objects" contain relevant information such as size and a list of keys (for dictionaries) in addition to lists of generic cJSON structs (cJSON_Generic_t). Data types on the other hand only contain a pointer to a variable to minimize memory usage. The below image shows a graphical overview of how the different data types are linked to each other: