janssonのexample

jass.c

#include<stdio.h>
#include<stdlib.h>
#include<jansson.h>


void jansson_pack_stdout_free(json_t *root) {
  char *out = json_dumps(root, JSON_ENCODE_ANY);
  printf("out:%s\r\n", out);
  free(root);
  free(out);
}

void jansson_pack_test(void) {
  json_t *root;
  char *out;

  /* Build an empty JSON object */
  root = json_pack("{}");
  jansson_pack_stdout_free(root);

  /* Build the JSON object {"foo": 42, "bar": 7} */
  root = json_pack("{sisi}", "foo", 42, "bar", 7);
  jansson_pack_stdout_free(root);

  /* Like above, ':', ',' and whitespace are ignored */
  root = json_pack("{s:i, s:i}", "foo", 42, "bar", 7);
  jansson_pack_stdout_free(root);

  /* Build the JSON array [[1, 2], {"cool": true}] */
  root = json_pack("[[i,i],{s:b}]", 1, 2, "cool", 1);
  jansson_pack_stdout_free(root);

  /* Build a string from a non-null terminated buffer */
  char buffer[4] = {'t', 'e', 's', 't'};
  root = json_pack("[s#]", buffer, 4);
  jansson_pack_stdout_free(root);

  /* Concatenate strings together to build the JSON string "foobarbaz" */
  root = json_pack("s++", "foo", "bar", "baz");
  jansson_pack_stdout_free(root);

  /* Create an empty object or array when optional members are missing */
  root = json_pack("s:s*,s:o*,s:0*", "foo", NULL, "bar", NULL, "baz", NULL);
  jansson_pack_stdout_free(root);

  root = json_pack("s*,o*,0*", NULL, NULL, NULL);
  jansson_pack_stdout_free(root);
}

void jansson_decref_test() {
  json_t *array, *integer;

  array = json_array();
  integer = json_integer(42);
  
  char *out = json_dumps(array, JSON_ENCODE_ANY);
  printf("out:%s\r\n", out);
  free(out);
  
  json_array_append(array, integer);

  out = json_dumps(array, JSON_ENCODE_ANY);
  printf("out:%s\r\n", out);
  free(out);

  out = json_dumps(integer, JSON_ENCODE_ANY);
  printf("out:%s\r\n", out);
  free(out);

  // メモリ解放？
  json_decref(integer);
}

int main(void){
  jansson_pack_test();
  puts("");
  jansson_decref_test();
  return 0;
}

/**
 * $ brew install jansson
 * $ gcc -ljansson -o jass jass.c
 */

/*
# output
out:{}
out:{"foo": 42, "bar": 7}
out:{"foo": 42, "bar": 7}
out:[[1, 2], {"cool": true}]
out:["test"]
out:"foobarbaz"
out:(null)
out:(null)

out:[]
out:[42]
out:42
out:[42]
out:42
*/

/**
 * ref:
 * https://jansson.readthedocs.io/en/latest/apiref.html#building-values
 */