JSON libraries

1.frozen 
 
 Output JSON objects in C as JSON formatted strings and parse 
JSON formatted strings back into the C presentation of 
the JSON objects.

FEATUES:
    • C and C++ complaint portable.
    • Several extra format specifiers supported.
JSON token:
This stucture contains-
 Pointer pointing to beginning of the value.
 Value length 
Type of the token
Token types are string,number,true,false,null,
object start, object end,array start and array end.
API’s:
    • json_scanf
     Scans json string directly into c/c++ variables.

    • json_printf
 Print c/c++ variables directly into output stream.

    • json_setf
      Modifies existing json_string.
      
    • json_fread
      Reads json from a file.
      
    • json_fprintf
      Writes json to a file.
      
    • json_scanf_array_elem
     Scan array element with given path and index

    • json_printf_array
 prints contiguous C arrays.

References:https://github.com/cesanta/frozen

SIZE of object file is 42 kBytes.


2.JSMN
 Minimalistic JSON parser in C.

FEATURES:
 Compatible with C89
 Single head library
 easily integrated into resource limited or
 emb projects
 API contains only 2 functions.
JSON token:
This structure contains-
 type
 start position in JSON data string
 end position in JSON data string
 size
Token types are-object,array,string,
primitive(number/boolean/true-false/null)
API’s:
    •  jsmn_init
       Create JSON parser over array of tokens.
    •  jsmn_parse
       Parses JSON data string into array of tokens,
each describing JSON object.

References:https://github.com/zserge/jsmn

SIZE of object file is upto 26 kBytes.


3.JSON-C

 JSON-C implements referrence counting object that 
allows you to easily construct JSON objects in c,
output them as JSON formatted strings and parse 
JSON formatted strings back into c 
representation of JSON objects.
FEATURES:
JSON token:
Token types are boolean,double,int,object,array,string.
API’s:
    • json_object_to_json_string
      Stringify object to JSON format grabbing the 
shared ownership of object.
      
    • json_object_get
      Increament reference count of json_object.
      
    • json_object_put
      Decrement reference count of json_object,and free 
it if reaches to zero.
      
    • json_object_userdata_to_json_string
      Copy the userdata string to over the 
destination buffer.
      
    • json_object_new_array
      Create a new empty json_object of type 
json_type_array.
      
    • json_object_get_array
      Get the arraylist of json_object of type 
json_type_array.
      
    • json_object_array_add
      Add an element to the end of json_object 
of type json_type_array.
      
    • json_obect_array_put_idx
      Insert or replace an element at a specified 
index of the array.
      
    • json_object_array_get_idx
      Get the element at specifies index of the 
array.
      
All these functions for array are also defined for 
following json_types- 
boolean,double,int,int64,object .

References:https://github.com/json-c/json-c

SIZE of object file is upto 300 kBytes.