#include <assert.h>

/* treat as opaque */
struct array {
   void **v;
   unsigned num, max;
};

struct array *array_create(void);
void array_init(struct array *a);
void array_cleanup(struct array *a);
void array_destroy(struct array *a);

static inline unsigned array_num(const struct array *a);
static inline void *array_get(const struct array *a, unsigned ix);
static inline void array_set(struct array *a, unsigned ix, void *ptr);
unsigned array_add(struct array *a, void *ptr);
void array_setsize(struct array *a, unsigned newsize);

/* compact, removing any null elements */
void array_nonulls(struct array *a);

/* x and y are pointers that were placed in the array */
void array_sort(struct array *a, int (*f)(void *x, void *y));

static inline unsigned array_num(const struct array *a) {
   return a->num;
}

static inline void *array_get(const struct array *a, unsigned ix) {
   assert(ix < a->num);
   return a->v[ix];
}

static inline void array_set(struct array *a, unsigned ix, void *ptr) {
   assert(ix < a->num);
   a->v[ix] = ptr;
}