K.I.S.S JSON composer library in C.

Features:

• No allocation
• CJSON style
• Small and hackable
• Custom runtime newline
• Handle null strings
• Custom null value for numbers (eg. -999 will be replaced with null)
• Floating point support can be disabled
• Compile time minimisation
• Always produces valid json
• Alerts the user if a key was skiped (not enough room in buffer)
• MIT licence

Limitations:

• Key pointers are not checked
• No arrays of objects (use for loop)

• kiss-json is not a parser, use jsmn for memory efficient parsing
• The default output format is not the prettiest, its ment to be a good balance between readability and memeory usage. Pass the output to jq to make it pretty.

Versions follow the standard Semantic Versioning system.

For a full working example, check main.c.

   char root[1024] = {0};

   kjson_t json = KJSON_INITIALISE(root);
   kjson_t *jsonHandle = &json;

   kJSON_InitRoot(jsonHandle);

   int digits[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
   const char *job = NULL;

   kJSON_InsertArrayInt(jsonHandle, "digits", digits, array_size(digits));

   kJSON_EnterObject(jsonHandle, "people");
   {
      kJSON_EnterObject(jsonHandle, "bob");
      {
         kJSON_InsertString(jsonHandle, "name", "Bob");
         kJSON_InsertString(jsonHandle, "job", job);
         kJSON_InsertUnsignedNumber(jsonHandle, "age", 32);
         kJSON_InsertBoolean(jsonHandle, "married", false);
         kJSON_InsertString(jsonHandle, "car", "🚗");
         kJSON_InsertNumber(jsonHandle, "balance", -300);
      }
      kJSON_ExitObject(jsonHandle);
   }
   kJSON_ExitObject(jsonHandle);

   kJSON_ExitRoot(jsonHandle);

   // Reset
   json.tail = json.root;
   json.size = 0;

Output with CONFIG_KJSON_SMALLEST (1):

{"digits":[0,1,2,3,4,5,6,7,8,9],"people":{"bob":{"name":"Bob","job":null,"age":32,"married":false,"car":"🚗","balance":-300}}}

Output with CONFIG_KJSON_SMALLEST (0):

{
"digits":	[0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
"people":	{
	"bob":	{
		"name":	"Bob",
		"job":	null,
		"age":	32,
		"married":	false,
		"car":	"🚗",
		"balance":	-300
	}
}
}

• cJSON - "Ultralightweight JSON parser in ANSI C" -> requires dynamic allocation
• jsmn - "Jsmn is a world fastest JSON parser/tokenizer." -> great for parsing
• tiny-json - "The tiny-json is a versatile and easy to use json parser in C suitable for embedded systems."
• microtojson - "A simple embedded friendly JSON generator."
• json-maker - "C library used to code JSON objects in null-terminated strings"