A ring-buffer generation utility

ringbuffer.h

/*
	simple ring buffer
*/
#ifndef RING_BUFFER_H_
#define RING_BUFFER_H_

enum E_RING_BUFFERS { e_RING_OK = 0, e_RING_EMPTY, e_RING_FULL, e_RING_ERROR };

#define T_RING(T, tag, len)\
	struct tag { T buffer[len]; unsigned int head, tail; };\
	static inline void RING_##tag##_init(struct tag *const o) { o->head = o->tail = 0; }\
	const unsigned int RING_##tag##_length = len;\
	static inline unsigned int RING_##tag##_count(struct tag *const o) { return (len + o->head - o->tail) % len; }\
	static inline unsigned int RING_####tag##_space(struct tag *const o) { return len - RING_##tag##_count(o); }\
	static inline enum E_RING_BUFFERS RING_##tag##_add(struct tag *const o, T *const item)\
	{\
		if ((o->head > len) | (o->tail > len)) return e_RING_ERROR;\
		if (RING_##tag##_count(o) == len) return e_RING_FULL;\
		memcpy(o->buffer + o->tail, item, sizeof(T));\
		o->head = (o->head < len) ? o->head + 1 : 0;\
		return e_RING_OK;\
	}\
	static inline enum E_RING_BUFFERS RING_##tag##_get(struct tag *const o, T *const item)\
	{\
		if ((o->head > len) | (o->tail > len)) return e_RING_ERROR;\
		if (RING_##tag##_count(o) == 0) return e_RING_EMPTY;\
		memcpy(item, &o->buffer + o->tail, sizeof(T));\
		o->tail = (o->tail < len) ? o->tail + 1 : 0;\
		return e_RING_OK;\
	}

#endif // RING_BUFFER_H_