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RIOT/sys/tsrb/tsrb.c
Marian Buschsieweke 0d0b14de29
sys/tsrb: Make thread-safe
Drop the requirement of having only one writer and one reader, as the name of
the ring-buffer does not indicate any limitation on the thread-safety. The
two-threads-one-buffer kind of ring buffer can be reintroduced with a different
name.
2020-10-13 10:32:41 +02:00

91 lines
1.7 KiB
C

/*
* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup sys
* @{
* @file
* @brief thread-safe ringbuffer implementation
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
*
* @}
*/
#include "irq.h"
#include "tsrb.h"
static void _push(tsrb_t *rb, uint8_t c)
{
rb->buf[rb->writes++ & (rb->size - 1)] = c;
}
static uint8_t _pop(tsrb_t *rb)
{
return rb->buf[rb->reads++ & (rb->size - 1)];
}
int tsrb_get_one(tsrb_t *rb)
{
int retval = -1;
unsigned irq_state = irq_disable();
if (!tsrb_empty(rb)) {
retval = _pop(rb);
}
irq_restore(irq_state);
return retval;
}
int tsrb_get(tsrb_t *rb, uint8_t *dst, size_t n)
{
size_t tmp = n;
unsigned irq_state = irq_disable();
while (tmp && !tsrb_empty(rb)) {
*dst++ = _pop(rb);
tmp--;
}
irq_restore(irq_state);
return (n - tmp);
}
int tsrb_drop(tsrb_t *rb, size_t n)
{
size_t tmp = n;
unsigned irq_state = irq_disable();
while (tmp && !tsrb_empty(rb)) {
_pop(rb);
tmp--;
}
irq_restore(irq_state);
return (n - tmp);
}
int tsrb_add_one(tsrb_t *rb, uint8_t c)
{
int retval = -1;
unsigned irq_state = irq_disable();
if (!tsrb_full(rb)) {
_push(rb, c);
retval = 0;
}
irq_restore(irq_state);
return retval;
}
int tsrb_add(tsrb_t *rb, const uint8_t *src, size_t n)
{
size_t tmp = n;
unsigned irq_state = irq_disable();
while (tmp && !tsrb_full(rb)) {
_push(rb, *src++);
tmp--;
}
irq_restore(irq_state);
return (n - tmp);
}