main-helper.h

#ifndef MAIN_HELPER_H_
#define MAIN_HELPER_H_


struct ptr_array {
	void **ptrs;
	int l;
	int size;
};

#define CHK_BAD_RET(check, ...)			\
	if (check) BAD_RET(__VA_ARGS__);

#define BAD_RET(...)				\
	do { fprintf(stderr, __VA_ARGS__); return -1; } while(0)

#define TRY_ALLOC_AT(s, a,pa,i,size)					\
	do {								\
		int old_i = s->nb_##a;					\
		if (s->nb_##a <= i) {					\
			int sz = i + 1;					\
			int oidx = ptr_array_get_idx(pa, s->a);		\
			s->a = osc_realloc(s->a, sz * size);		\
			CHK_BAD_RET(!s->a, "allocation fail\n");	\
			if (oidx < 0) {					\
			        CHK_BAD_RET(ptr_array_append(pa, s->a) < 0, \
					    "ptr_array_append fail");	\
			} else {					\
				pa->ptrs[oidx] = s->a;			\
				s->a = pa->ptrs[oidx];			\
			}						\
			memset(s->a + old_i, 0, size * (sz - old_i));	\
			s->nb_##a = sz;					\
		}							\
	} while (0)

/*
 * use to be sizeof v, but if I pass "" to SET_NEXT, sizeof v is 1, and I expect
 * char *,
 * because the array can contain int and double too, I'll gowith allocated the
 * biggerst size for all
 */
#define OBJ_SIZE 8

/* a is an array with a flexible size, v is the value to push,
 * and pa is used to store the pointer so that we can easily free everything later.
 */
#define SET_NEXT(a,v,pa) do {						\
		int cnt;						\
		if (!a) {						\
			a = calloc(64, OBJ_SIZE);				\
			if (!a) break;					\
			if (ptr_array_append(pa, a) < 0)		\
				break;					\
		}							\
		for (cnt = 0; a[cnt]; ++cnt);				\
		if (cnt && (cnt % 63) == 0) {				\
			int idx = ptr_array_get_idx(pa, a);		\
			pa->ptrs[idx] = realloc(a, (cnt + 1 + 64) * OBJ_SIZE); \
			if (!pa->ptrs[idx]) { free(a); break; }		\
			a = pa->ptrs[idx];				\
			memset(a + cnt + 1, 0, 64 * OBJ_SIZE);		\
		}							\
		a[cnt] = v;						\
	} while (0)

static inline int ptr_array_append(struct ptr_array *pa, void *ptr)
{
	if (!(pa->l & 63)) { /* need grow up */
		void *old = pa->ptrs;

		pa->size += 64;
		pa->ptrs = realloc(old, pa->size);
		if (!pa->ptrs) {
			/* if realloc return NULL. old is left untouched */
			#pragma GCC diagnostic ignored "-Wuse-after-free"
			free(old);
			#pragma GCC diagnostic pop
			return -1;
		}
	}
	pa->ptrs[pa->l++] = ptr;
	return 0;
}

static inline int ptr_array_get_idx(struct ptr_array *pa, void *ptr)
{
	for (int i = 0; i < pa->l; ++i)
		if (pa->ptrs[i] == ptr)
			return i;
	return -1;
}

static inline int ptr_array_free_all(struct ptr_array *pa)
{
	if (pa->ptrs) {
		for (int i = 0; i < pa->l; ++i) {
			free(pa->ptrs[i]);
		}
		free(pa->ptrs);
		pa->ptrs = NULL;
		pa->size = 0;
		pa->l = 0;
	}
	return 0;
}

#define auto_ptr_array __attribute__((cleanup(ptr_array_free_all)))

#endif /* MAIN_HELPER_H_ */