simtrace2/firmware/libcommon/source/ringbuffer.c

92 lines
2.1 KiB
C

/* Ring buffer
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
*/
#include "ringbuffer.h"
#include "trace.h"
#include "utils.h"
/* WARNING: Since console output is internally using this ringbuffer to implement
* buffered writes, we cannot use any TRACE_*() or printf() style functions here,
* as it would create infinite recursion! */
void rbuf_reset(volatile ringbuf * rb)
{
unsigned long state;
local_irq_save(state);
rb->ird = 0;
rb->iwr = 0;
local_irq_restore(state);
}
uint8_t rbuf_read(volatile ringbuf * rb)
{
unsigned long state;
uint8_t val;
local_irq_save(state);
val = rb->buf[rb->ird];
rb->ird = (rb->ird + 1) % RING_BUFLEN;
local_irq_restore(state);
return val;
}
uint8_t rbuf_peek(volatile ringbuf * rb)
{
return rb->buf[rb->ird];
}
bool rbuf_is_empty(volatile ringbuf * rb)
{
return rb->ird == rb->iwr;
}
static bool __rbuf_is_full(volatile ringbuf * rb)
{
return rb->ird == (rb->iwr + 1) % RING_BUFLEN;
}
bool rbuf_is_full(volatile ringbuf * rb)
{
unsigned long state;
bool rc;
local_irq_save(state);
rc = rb->ird == (rb->iwr + 1) % RING_BUFLEN;
local_irq_restore(state);
return rc;
}
int rbuf_write(volatile ringbuf * rb, uint8_t item)
{
unsigned long state;
local_irq_save(state);
if (!__rbuf_is_full(rb)) {
rb->buf[rb->iwr] = item;
rb->iwr = (rb->iwr + 1) % RING_BUFLEN;
local_irq_restore(state);
return 0;
} else {
local_irq_restore(state);
return -1;
}
}