48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
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#ifndef RING_BUFFER_H
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#define RING_BUFFER_H
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/*--------------------------------------------------------------------
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* Ring buffer to store scan codes from keyboard
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*------------------------------------------------------------------*/
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#ifndef RBUF_SIZE
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# define RBUF_SIZE 32
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#endif
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#include <util/atomic.h>
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#include <stdint.h>
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#include <stdbool.h>
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static uint8_t rbuf[RBUF_SIZE];
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static uint8_t rbuf_head = 0;
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static uint8_t rbuf_tail = 0;
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static inline bool rbuf_enqueue(uint8_t data) {
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bool ret = false;
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ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
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uint8_t next = (rbuf_head + 1) % RBUF_SIZE;
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if (next != rbuf_tail) {
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rbuf[rbuf_head] = data;
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rbuf_head = next;
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ret = true;
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}
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}
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return ret;
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}
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static inline uint8_t rbuf_dequeue(void) {
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uint8_t val = 0;
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ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
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if (rbuf_head != rbuf_tail) {
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val = rbuf[rbuf_tail];
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rbuf_tail = (rbuf_tail + 1) % RBUF_SIZE;
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}
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}
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return val;
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}
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static inline bool rbuf_has_data(void) {
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bool has_data;
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ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { has_data = (rbuf_head != rbuf_tail); }
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return has_data;
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}
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static inline void rbuf_clear(void) {
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ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { rbuf_head = rbuf_tail = 0; }
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}
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#endif /* RING_BUFFER_H */
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