#define _vec_needsgrow(A,N) ((!(A)) || (_vec_end(A) + (N) >= _vec_beg(A)))
#define _vec_mightgrow(A,N) (_vec_needsgrow((A), (N)) ? _vec_forcegrow((A),(N)) : 0)
#define _vec_forcegrow(A,N) _util_vec_grow((void**)&(A), (N), sizeof(*(A)))
+#define _vec_remove(A,S,I,N) (memmove((char*)(A)+(I)*(S),(char*)(A)+((I)+(N))*(S),(S)*(vec_size(A)-(I)-(N))), _vec_end(A)-=(N))
void _util_vec_grow(void **a, size_t i, size_t s);
/* exposed interface */
#define vec_free(A) ((A) ? (mem_d(_vec_raw(A)), (A) = NULL) : 0)
#define vec_add(A,N) (_vec_mightgrow((A),(N)), _vec_end(A)+=(N), &(A)[_vec_end(A)-(N)])
#define vec_last(A) ((A)[_vec_end(A)-1])
#define vec_append(A,N,S) memcpy(vec_add((A), (N)), (S), N * sizeof(*(S)))
-#define _vec_remove(A,S,I,N) (memmove((char*)(A)+(I)*(S),(char*)(A)+((I)+(N))*(S),(S)*(vec_size(A)-(I)-(N))), _vec_end(A)-=(N))
#define vec_remove(A,I,N) _vec_remove((A), sizeof(*(A)), (I), (N))
#define vec_pop(A) vec_remove((A), _vec_end(A)-1, 1)
/* these are supposed to NOT reallocate */