81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/**
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* Copyright 2022 Colin Lam, Ploopy Corporation
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* SPECIAL THANKS TO:
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* @miketeachman (github.com/miketeachman)
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* @jimmo (github.com/jimmo)
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* @dlech (github.com/dlech)
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* for their exceptional work on the I2S library for the rp2 port of the
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* Micropython project (github.com/micropython/micropython).
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*/
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#include "pico/stdlib.h"
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#include "ringbuf.h"
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// TODO can this be sped up by using uint32_t instead of uint8_t?
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// Ring Buffer
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// Thread safe when used with these constraints:
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// - Single Producer, Single Consumer
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// - Sequential atomic operations
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// One byte of capacity is used to detect buffer empty/full
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void ringbuf_init(ring_buf_t *rbuf, uint8_t *buffer, size_t size) {
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rbuf->buffer = buffer;
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rbuf->size = size;
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rbuf->head = 0;
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rbuf->tail = 0;
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}
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bool ringbuf_push(ring_buf_t *rbuf, uint8_t data) {
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size_t next_tail = (rbuf->tail + 1) % rbuf->size;
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if (next_tail != rbuf->head) {
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rbuf->buffer[rbuf->tail] = data;
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rbuf->tail = next_tail;
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return true;
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}
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// full
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return false;
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}
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bool ringbuf_pop(ring_buf_t *rbuf, uint8_t *data) {
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if (rbuf->head == rbuf->tail) {
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// empty
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return false;
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}
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*data = rbuf->buffer[rbuf->head];
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rbuf->head = (rbuf->head + 1) % rbuf->size;
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return true;
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}
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bool ringbuf_is_empty(ring_buf_t *rbuf) {
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return rbuf->head == rbuf->tail;
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}
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bool ringbuf_is_full(ring_buf_t *rbuf) {
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return ((rbuf->tail + 1) % rbuf->size) == rbuf->head;
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}
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size_t ringbuf_available_data(ring_buf_t *rbuf) {
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return (rbuf->tail - rbuf->head + rbuf->size) % rbuf->size;
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}
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size_t ringbuf_available_space(ring_buf_t *rbuf) {
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return rbuf->size - ringbuf_available_data(rbuf) - 1;
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} |