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#ifndef RBUFFER_H
#define RBUFFER_H
#include <stddef.h>
struct rbuffer_t {
char* address_begin;
char* address_end;
char* volatile head;
char* volatile tail;
};
#define RBUFFER_INIT(array, length) \
{ \
.address_begin = array, \
.address_end = array + length, \
.head = array, \
.tail = array \
}
#define INIT_RBUFFER(buffer, array, length) \
(buffer)->address_begin = (array); \
(buffer)->address_end = (array) + (length); \
(buffer)->head = (array); \
(buffer)->tail = (array)
static inline int rbuffer_empty(struct rbuffer_t* const rb) {
return rb->head == rb->tail;
}
static inline int rbuffer_write(struct rbuffer_t* const rb, char data) {
char* next_head = rb->head + 1;
if(next_head >= rb->address_end) next_head = rb->address_begin;
if (rb->tail == next_head) return -1;
*rb->head = data;
rb->head = next_head;
return 0;
}
static inline int rbuffer_read(struct rbuffer_t* const rb, char* const data) {
if (rbuffer_empty(rb)) return -1;
*data = *rb->tail;
rb->tail += 1;
if(rb->tail >= rb->address_end) rb->tail = rb->address_begin;
return 0;
}
#endif
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