static UA_SByte jsoneq(const char *json, jsmntok_t *tok, const char *searchKey) {
    /* TODO: necessary?
       if(json == NULL
            || tok == NULL 
            || searchKey == NULL) {
        return -1;
    } */
    
    if(tok->type == JSMN_STRING) {
         if(strlen(searchKey) == (size_t)(tok->end - tok->start) ) {
             if(strncmp(json + tok->start,
                        (const char*)searchKey, (size_t)(tok->end - tok->start)) == 0) {
                 return 0;
             }   
         }
    }
    return -1;
}
static UA_SByte jsoneq(const char *json, jsmntok_t *tok, const char *searchKey) {
     
    
    if(tok->type == JSMN_STRING) {
         if(strlen(searchKey) == (size_t)(tok->end - tok->start) ) {
             if(strncmp(json + tok->start,
                        (const char*)searchKey, (size_t)(tok->end - tok->start)) == 0) {
                 return 0;
             }   
         }
    }
    return -1;
}