json_serializer.hpp File Reference

#include "appd_iot_interface.h"

Go to the source code of this file.

Data Structures
struct	json_t
	JSON struct which holds json string in a buffer. More...

Enumerations
enum	json_ops_t {   DEINIT, INIT, START_ARRAY, START_OBJECT,   ADD_DATA, END_OBJECT, END_ARRAY }
	Enums to keep track of last JSON Operation completed. More...

Functions
json_t *	appd_iot_json_init (void)
	Creates, Initializes and returns a new json struct. More...
appd_iot_error_code_t	appd_iot_json_start_array (json_t *json, const char *array_name)
	starts json array by adding char '[' to json buf. If a name is given it will be "name":[ More...
appd_iot_error_code_t	appd_iot_json_start_object (json_t *json, const char *object_name)
	starts json object by adding char '{' to json buf. If a name is given it will be "name":{ More...
appd_iot_error_code_t	appd_iot_json_end_object (json_t *json)
	ends json object by adding char '}' to json buf. More...
appd_iot_error_code_t	appd_iot_json_end_array (json_t *json)
	ends json object by adding char ']' to json buf. More...
appd_iot_error_code_t	appd_iot_json_add_string_key_value (json_t *json, const char *key, const char *strval)
	adds key:value pair to json object with value as string More...
appd_iot_error_code_t	appd_iot_json_add_integer_key_value (json_t *json, const char *key, int64_t intval)
	adds key:value pair to json object with value as 64 bit integer More...
appd_iot_error_code_t	appd_iot_json_add_double_key_value (json_t *json, const char *key, double doubleval)
	adds key:value pair to json object with value as double More...
appd_iot_error_code_t	appd_iot_json_add_boolean_key_value (json_t *json, const char *key, bool boolval)
	adds key:value pair to json object with value as boolean More...
appd_iot_error_code_t	appd_iot_json_add_string_value (json_t *json, const char *value)
	adds value to json object. This function is typically used to add string values to JSON arrays More...
appd_iot_error_code_t	appd_iot_json_add_integer_value (json_t *json, int64_t intval)
	adds value to json object. This function is typically used to add integer values to JSON arrays More...
appd_iot_error_code_t	appd_iot_json_add_double_value (json_t *json, double doubleval)
	adds value to json object. This function is typically used to add double values to JSON arrays More...
appd_iot_error_code_t	appd_iot_json_add_boolean_value (json_t *json, bool boolval)
	adds value to json object. This function is typically used to add boolean values to JSON arrays More...
const char *	appd_iot_json_get_string (json_t *json)
	returns the json string constructed so far. More...
const char *	appd_iot_json_pretty_print (json_t *json)
	format and returns json string with line breaks, indentiation at start/end of objects/arrays More...
void	appd_iot_json_free (json_t *json)
	frees json structure More...

Enumeration Type Documentation

json_ops_t

enum json_ops_t

Enums to keep track of last JSON Operation completed.

Enumerator
DEINIT
INIT
START_ARRAY
START_OBJECT
ADD_DATA
END_OBJECT
END_ARRAY

{
  DEINIT,
  INIT,
  START_ARRAY,
  START_OBJECT,
  ADD_DATA,
  END_OBJECT,
  END_ARRAY
} json_ops_t;

Function Documentation

appd_iot_json_init()

json_t* appd_iot_json_init

(

void

)

Creates, Initializes and returns a new json struct.

Returns

json_t pointer to the newly created json object

{
  json_t* json = (json_t*)calloc(1, sizeof(json_t));

  if (json == NULL)
  {
    return NULL;
  }

  json->buf = (char*)calloc(1, INITIAL_JSON_SIZE + 1);

  if (json->buf == NULL)
  {
    free(json);
    return NULL;
  }

  json->max_len = INITIAL_JSON_SIZE;
  json->last_op = INIT;

  return json;
}

appd_iot_json_start_array()

appd_iot_error_code_t appd_iot_json_start_array	(	json_t *	json,
		const char *	array_name
	)

starts json array by adding char '[' to json buf. If a name is given it will be "name":[

Parameters

json	struct which contains the json buf
array_name	has the string for the key to json array

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_start(json, START_ARRAY_CHAR, array_name);
}

appd_iot_json_start_object()

appd_iot_error_code_t appd_iot_json_start_object	(	json_t *	json,
		const char *	object_name
	)

starts json object by adding char '{' to json buf. If a name is given it will be "name":{

Parameters

json	struct which contains the json buf
object_name	has the string for the key to json object

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_start(json, START_OBJECT_CHAR, object_name);
}

appd_iot_json_end_object()

appd_iot_error_code_t appd_iot_json_end_object

(

json_t *

json

)

ends json object by adding char '}' to json buf.

Parameters

json	struct which contains the json buf

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_end(json, END_OBJECT_CHAR);
}

appd_iot_json_end_array()

appd_iot_error_code_t appd_iot_json_end_array

(

json_t *

json

)

ends json object by adding char ']' to json buf.

Parameters

json	struct which contains the json buf

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_end(json, END_ARRAY_CHAR);
}

appd_iot_json_add_string_key_value()

appd_iot_error_code_t appd_iot_json_add_string_key_value	(	json_t *	json,
		const char *	key,
		const char *	strval
	)

adds key:value pair to json object with value as string

Parameters

json	struct which contains the json buf
key	contains string representing key
strval	contains string representing value

Returns

appd_iot_error_code_t indicating function execution status

{
  //do escape, get the size
  return appd_iot_json_add_key_value(json, key, (void*)strval, APPD_IOT_STRING);
}

appd_iot_json_add_integer_key_value()

appd_iot_error_code_t appd_iot_json_add_integer_key_value	(	json_t *	json,
		const char *	key,
		int64_t	intval
	)

adds key:value pair to json object with value as 64 bit integer

Parameters

json	struct which contains the json buf
key	contains string representing key
intval	contains integer representing value

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_key_value(json, key, (void*)(&intval), APPD_IOT_INTEGER);
}

appd_iot_json_add_double_key_value()

appd_iot_error_code_t appd_iot_json_add_double_key_value	(	json_t *	json,
		const char *	key,
		double	doubleval
	)

adds key:value pair to json object with value as double

Parameters

json	struct which contains the json buf
key	contains string representing key
doubleval	contains double representing value

Returns

appd_iot_error_code_t indicating function execution status

adds key:value pair to json object with value as double

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_key_value(json, key, (void*)(&doubleval), APPD_IOT_DOUBLE);
}

appd_iot_json_add_boolean_key_value()

appd_iot_error_code_t appd_iot_json_add_boolean_key_value	(	json_t *	json,
		const char *	key,
		bool	boolval
	)

adds key:value pair to json object with value as boolean

Parameters

json	struct which contains the json buf
key	contains string representing key
boolval	contains boolean representing value

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_key_value(json, key, (void*)(&boolval), APPD_IOT_BOOLEAN);
}

appd_iot_json_add_string_value()

appd_iot_error_code_t appd_iot_json_add_string_value	(	json_t *	json,
		const char *	value
	)

adds value to json object. This function is typically used to add string values to JSON arrays

Parameters

json	struct which contains the json buf
value	contains string to be added

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_value(json, (void*)value, APPD_IOT_STRING);
}

appd_iot_json_add_integer_value()

appd_iot_error_code_t appd_iot_json_add_integer_value	(	json_t *	json,
		int64_t	intval
	)

adds value to json object. This function is typically used to add integer values to JSON arrays

Parameters

json	struct which contains the json buf
intval	contains integer to be added

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_value(json, (void*)(&intval), APPD_IOT_INTEGER);
}

appd_iot_json_add_double_value()

appd_iot_error_code_t appd_iot_json_add_double_value	(	json_t *	json,
		double	doubleval
	)

adds value to json object. This function is typically used to add double values to JSON arrays

Parameters

json	struct which contains the json buf
doubleval	contains integer to be added

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_value(json, (void*)(&doubleval), APPD_IOT_DOUBLE);
}

appd_iot_json_add_boolean_value()

appd_iot_error_code_t appd_iot_json_add_boolean_value	(	json_t *	json,
		bool	boolval
	)

adds value to json object. This function is typically used to add boolean values to JSON arrays

Parameters

json	struct which contains the json buf
boolval	contains boolean to be added

Returns

appd_iot_error_code_t indicating function execution status

{
  return appd_iot_json_add_value(json, (void*)(&boolval), APPD_IOT_BOOLEAN);
}

appd_iot_json_get_string()

const char* appd_iot_json_get_string

(

json_t *

json

)

returns the json string constructed so far.

Parameters

json	struct which contains the json buf

Returns

char pointer containing the json string.

{
  return json->buf;
}

appd_iot_json_pretty_print()

const char* appd_iot_json_pretty_print

(

json_t *

json

)

format and returns json string with line breaks, indentiation at start/end of objects/arrays

Parameters

json	struct which contains the json buf

Returns

char pointer containing the json string.

{
  if (json == NULL)
  {
    appd_iot_log(APPD_IOT_LOG_ERROR, "JSON Object is Null");
    return NULL;
  }

  if (json->buf == NULL)
  {
    appd_iot_log(APPD_IOT_LOG_ERROR, "JSON String Buffer is Null");
    return NULL;
  }

  if (json->printbuf != NULL)
  {
    return json->printbuf;
  }

  size_t printbuf_size = 2 * json->len;
  json->printbuf = (char*)calloc(1, printbuf_size);
  size_t printbuf_len = 0;

  int width = 0;

  snprintf(json->printbuf + printbuf_len, 2, "\n");
  printbuf_len += 1;

  for (size_t i = 0; i < json->len; i++)
  {
    if (json->buf[i] == START_ARRAY_CHAR)
    {
      width += 2; //for indentation
    }

    if (json->buf[i] == START_OBJECT_CHAR)
    {
      width += 2; //for indentation
    }

    if (json->buf[i] == END_ARRAY_CHAR)
    {
      width -= 2; //remove indentiation
    }

    if (json->buf[i] == END_OBJECT_CHAR)
    {
      width -= 2; //remove indentiation
    }

    if ((printbuf_len + width + 2) > printbuf_size)
    {
      json->printbuf = (char*)realloc(json->printbuf, printbuf_size * 2);

      if (json->printbuf == NULL)
      {
        appd_iot_log(APPD_IOT_LOG_ERROR, "Failed to Realloc Memory");
        free(json->printbuf);
        return NULL;
      }

      printbuf_size = printbuf_size * 2;
    }

    //print newline and add indentation before closing
    if (json->buf[i] == END_ARRAY_CHAR || json->buf[i] == END_OBJECT_CHAR)
    {
      if (width == 0)
      {
        width = width + 1; //if no indentation, print new line
      }

      snprintf(json->printbuf + printbuf_len, width + 1, "\n%-*s", width, "");
      printbuf_len += width;
    }

    snprintf(json->printbuf + printbuf_len, 2, "%c", json->buf[i]);
    printbuf_len += 1;

    //print newline and add indentation after opening
    if (json->buf[i] == START_ARRAY_CHAR || json->buf[i] == START_OBJECT_CHAR ||
        json->buf[i] == JSON_DELIMITER)
    {
      snprintf(json->printbuf + printbuf_len, width + 1, "\n%-*s", width, "");
      printbuf_len += width;
    }
  }

  json->printbuf[printbuf_len] = '\0';

  return json->printbuf;
}

appd_iot_json_free()

void appd_iot_json_free

(

json_t *

json

)

frees json structure

Parameters

json	struct which contains the json buf

{
  if (json == NULL)
  {
    return;
  }

  if (json->buf != NULL)
  {
    free(json->buf);
  }

  if (json->printbuf != NULL)
  {
    free(json->printbuf);
  }

  free(json);

  return;
}