struct ucw_allocator {
void * (*alloc)(struct ucw_allocator *alloc, size_t size);
void * (*realloc)(struct ucw_allocator *alloc, void *ptr, size_t old_size, size_t new_size);
struct ucw_allocator {
void * (*alloc)(struct ucw_allocator *alloc, size_t size);
void * (*realloc)(struct ucw_allocator *alloc, void *ptr, size_t old_size, size_t new_size);