90 lines
3.0 KiB
C
90 lines
3.0 KiB
C
/* Copyright 2019 Michiel Visser
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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 2 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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#include "uart_tx_ringbuf.h"
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#include "hal.h"
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int uart_tx_ringbuf_elements(uart_tx_ringbuf_t *ringbuf) {
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return ringbuf->head - ringbuf->tail;
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}
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int uart_tx_ringbuf_space(uart_tx_ringbuf_t *ringbuf) {
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return ringbuf->size - uart_tx_ringbuf_elements(ringbuf);
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}
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bool uart_tx_ringbuf_empty(uart_tx_ringbuf_t *ringbuf) {
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return uart_tx_ringbuf_elements(ringbuf) == 0;
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}
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bool uart_tx_ringbuf_full(uart_tx_ringbuf_t *ringbuf) {
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return uart_tx_ringbuf_elements(ringbuf) == ringbuf->size;
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}
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void uart_tx_ringbuf_start_transmission(uart_tx_ringbuf_t *ringbuf) {
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/* Do not start transmission when one is already in progress */
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if (ringbuf->sending_elements != 0) return;
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size_t elements = uart_tx_ringbuf_elements(ringbuf);
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/* Do not start transmission when ringbuffer is empty */
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if (elements == 0) return;
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/* Get the offset of the first and last item */
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size_t first_offset = (ringbuf->tail & (ringbuf->size - 1));
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/* Determine if this wraps around the end of the buffer */
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if (first_offset + elements >= ringbuf->size) {
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/* If so only send until the end of the buffer */
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elements = ringbuf->size - first_offset;
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}
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/* Send the selected elements */
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ringbuf->sending_elements = elements;
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uartStartSend(ringbuf->uart, elements, ringbuf->buf + first_offset);
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}
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void uart_tx_ringbuf_finish_transmission(uart_tx_ringbuf_t *ringbuf) {
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/* Update the tail of the ringbuffer */
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ringbuf->tail += ringbuf->sending_elements;
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/* Clear the sending elements */
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ringbuf->sending_elements = 0;
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}
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bool uart_tx_ringbuf_put(uart_tx_ringbuf_t *ringbuf, uint8_t c) {
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/* If the ringbuffer is full, ignore the request */
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if (uart_tx_ringbuf_full(ringbuf)) return false;
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/* Put the character into the ringbuffer */
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size_t head_offset = (ringbuf->head & (ringbuf->size - 1));
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ringbuf->buf[head_offset] = c;
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ringbuf->head++;
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return true;
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}
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bool uart_tx_ringbuf_write(uart_tx_ringbuf_t *ringbuf, size_t count, void *data) {
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/* If there is not enough space, ignore the request */
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if (uart_tx_ringbuf_space(ringbuf) < count) return false;
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for (int i = 0; i < count; i++) {
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/* Put the character into the ringbuffer */
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size_t head_offset = (ringbuf->head & (ringbuf->size - 1));
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ringbuf->buf[head_offset] = ((uint8_t *) data)[i];
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ringbuf->head++;
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}
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return true;
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}
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