diff options
Diffstat (limited to 'src/modules/sdlog/sdlog_ringbuffer.c')
-rw-r--r-- | src/modules/sdlog/sdlog_ringbuffer.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/modules/sdlog/sdlog_ringbuffer.c b/src/modules/sdlog/sdlog_ringbuffer.c new file mode 100644 index 000000000..d7c8a4759 --- /dev/null +++ b/src/modules/sdlog/sdlog_ringbuffer.c @@ -0,0 +1,91 @@ +/**************************************************************************** + * + * 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; + } +} |