px4-firmware/apps/sdlog/sdlog_ringbuffer.c

92 lines
2.9 KiB
C

/****************************************************************************
*
* Copyright (C) 2013 PX4 Development Team. All rights reserved.
* Author: Lorenz Meier <lm@inf.ethz.ch>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file sdlog_log.c
* MAVLink text logging.
*
* @author Lorenz Meier <lm@inf.ethz.ch>
*/
#include <string.h>
#include <stdlib.h>
#include "sdlog_ringbuffer.h"
void sdlog_logbuffer_init(struct sdlog_logbuffer *lb, int size)
{
lb->size = size;
lb->start = 0;
lb->count = 0;
lb->elems = (struct sdlog_sysvector *)calloc(lb->size, sizeof(struct sdlog_sysvector));
}
int sdlog_logbuffer_is_full(struct sdlog_logbuffer *lb)
{
return lb->count == (int)lb->size;
}
int sdlog_logbuffer_is_empty(struct sdlog_logbuffer *lb)
{
return lb->count == 0;
}
// XXX make these functions thread-safe
void sdlog_logbuffer_write(struct sdlog_logbuffer *lb, const struct sdlog_sysvector *elem)
{
int end = (lb->start + lb->count) % lb->size;
memcpy(&(lb->elems[end]), elem, sizeof(struct sdlog_sysvector));
if (sdlog_logbuffer_is_full(lb)) {
lb->start = (lb->start + 1) % lb->size; /* full, overwrite */
} else {
++lb->count;
}
}
int sdlog_logbuffer_read(struct sdlog_logbuffer *lb, struct sdlog_sysvector *elem)
{
if (!sdlog_logbuffer_is_empty(lb)) {
memcpy(elem, &(lb->elems[lb->start]), sizeof(struct sdlog_sysvector));
lb->start = (lb->start + 1) % lb->size;
--lb->count;
return 0;
} else {
return 1;
}
}