opensteno_qmk/tmk_core/ring_buffer.h
Wez Furlong be4e75423a Tidy up atomicity in timer.c and ring_buffer.h
Adopt the macros for saving/restoring the interrupt state
that are provided by the avr gcc environment.

Removing intialization of the timer value; this shaves off
a few bytes because globals are default initialized to zero.
2016-11-27 22:58:34 -08:00

51 lines
1.2 KiB
C

#ifndef RING_BUFFER_H
#define RING_BUFFER_H
/*--------------------------------------------------------------------
* Ring buffer to store scan codes from keyboard
*------------------------------------------------------------------*/
#define RBUF_SIZE 32
#include <util/atomic.h>
static uint8_t rbuf[RBUF_SIZE];
static uint8_t rbuf_head = 0;
static uint8_t rbuf_tail = 0;
static inline void rbuf_enqueue(uint8_t data)
{
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
if (next != rbuf_tail) {
rbuf[rbuf_head] = data;
rbuf_head = next;
} else {
print("rbuf: full\n");
}
}
}
static inline uint8_t rbuf_dequeue(void)
{
uint8_t val = 0;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
if (rbuf_head != rbuf_tail) {
val = rbuf[rbuf_tail];
rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
}
}
return val;
}
static inline bool rbuf_has_data(void)
{
bool has_data;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
has_data = (rbuf_head != rbuf_tail);
}
return has_data;
}
static inline void rbuf_clear(void)
{
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
rbuf_head = rbuf_tail = 0;
}
}
#endif /* RING_BUFFER_H */