#ifndef RESERVOIR_H_MZSA8WJ3
#define RESERVOIR_H_MZSA8WJ3

#include <stdlib.h>

#include "buf.h"

#ifndef NDEBUG
#include "notify.h"
#endif /* NDEBUG */

/* A pool of buf_t */

typedef struct reservoir_ {
	size_t reservoir_sz; /* allocated slots */
	size_t reservoir_used; /* slots filled */
	unsigned long reservoir_tally; /* total number of items remembered */
	buf_t reservoir[];
} *reservoir_t;

#ifndef NDEBUG
#define D_RESERVOIR(__r__) do {\
	size_t i;\
		NOTIFY_DEBUG("reservoir:%p sz: %zu used:%zu tally:%zu", (__r__), (__r__)->reservoir_sz, (__r__)->reservoir_used, (__r__)->reservoir_tally);\
		for (i = 0; i < (__r__)->reservoir_sz; i++) {\
			D_BUF("reservoir[%zu] ", (__r__)->reservoir[i], i);\
		}\
} while (0)
#else /* NDEBUG */
#define D_RESERVOIR(...)
#endif /* NDEBUG */

/*	reservoir_new
	Allocate and return a new reservoir capable of holding #sz bufs.
*/
reservoir_t reservoir_new(size_t sz);

/*	reservoir_grow
	Increase the storage capacity of the reservoir pointed to by #preservoir
	by #growby bufs.
*/
int reservoir_grow(reservoir_t *preservoir, size_t growby);

/*	reservoir_remember
		Remember #buf, forgetting another buf at random if the reservoir
		pointed to by #preservoir is already full to capacity.
*/
void reservoir_remember(reservoir_t reservoir, buf_t buf);

/*	reservoir_write
	Write the contents of the bufs within #reservoir to #fd, each with a
	trailing #delim.
*/
int reservoir_write(int fd, reservoir_t reservoir, char delim);

/*	reservoir_write_meta
	Write metadata of #reservoir and #samples to fd.
*/
int reservoir_write_meta(int fd, reservoir_t reservoir, unsigned long samples, char delim);

#endif /* RESERVOIR_H_MZSA8WJ3 */