null.c

#include <stdlib.h>
#include <string.h>

#include "null.h"

JsonValue *match_null(char *json, int *index, int size)
{
  JsonValue *result = create_json_value();
  result->start = *index;
  result->end = *index;
  result->type = JSON_NULL;
  result->error->code = "";

  // remaining size should be 4 or 5
  if (size >= *index + 4)
  {
    free_json_error(result->error);
    result->error = NULL;

    for (int i = 0; i < 4; i++)
    {

      if (json[*index + i] != JSON_NULL_VALUE[i])
      {
        result->error = create_json_error(*index + i, "null-invalid-value");
        break;
      }

      result->end++;
    }
  }

  if (result->error != NULL && strcmp(result->error->code, ""))
  {
    result->error->code = "null-invalid-value";
  }

  if (result->error == NULL)
  {
    result->end--;
  }

  return result;
}