#ifndef RINGBUFFER_H
#define RINGBUFFER_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>

typedef struct {
  uint32_t head;
  uint32_t tail;
  uint32_t size;
  uint8_t data[];
} ringbuffer;

#define RINGBUFFER_STORAGE(NAME, SIZE) \
  uint8_t buf_##NAME##__LINE__[sizeof(ringbuffer) + SIZE]; \
  ringbuffer *NAME = (ringbuffer *)buf_##NAME##__LINE__;
#define RINGBUFFER_INIT(NAME, SIZE) \
  NAME->head = NAME->tail = 0; \
  NAME->size              = SIZE;
#define RINGBUFFER(NAME, SIZE) \
  RINGBUFFER_STORAGE(NAME, SIZE); \
  RINGBUFFER_INIT(NAME, SIZE);

/** Fully empties the ringbuffer */
void ringbuffer_rst(ringbuffer *buf);

/** The total capacity of the ringbuffer */
unsigned ringbuffer_capacity(ringbuffer *buf);

/** The free capacity of the ringbuffer */
unsigned ringbuffer_free(ringbuffer *buf);

/** The used capacity of the ringbuffer */
unsigned ringbuffer_level(ringbuffer *buf);

/** Non-zero if the ringbuffer is empty */
unsigned ringbuffer_empty(ringbuffer *buf);

/** Add data to the ringbuffer, return actual length of added data */
unsigned ringbuffer_add(ringbuffer *buf, void const *dat, unsigned len);

/** Get data from the ringbuffer, return actual length of retrieved data */
unsigned ringbuffer_get(ringbuffer *buf, void *dst, unsigned len);

/** Get data from the ringbuffer, but do not remove it. Return actual length of retrieved data. */
unsigned ringbuffer_peek(ringbuffer *buf, void *dst, unsigned len);

/** Remove data from the ringbuffer without reading it */
void ringbuffer_skip(ringbuffer *buf, unsigned len);

#ifdef __cplusplus
}
#endif
#endif