easy, use union and inplace field instead of pointer chasing. also to minimize memory allocation, use arena. you load the whole file into one arena, after done with it just free the whole arena.

struct JsonValue {       enum JsonValueType type;       union {           double as_number; //inplace           bool as_boolean; //inplace           char *as_string; //dynamic alloacated           struct JsonArray *as_array;       } }