mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-12-21 19:29:18 +00:00
Added ringbufindex module
This commit is contained in:
Simon Duquennoy
parent
5d1feac63e
commit
2112dff217
149
core/lib/ringbufindex.c
Normal file
149
core/lib/ringbufindex.c
Normal file
@ -0,0 +1,149 @@
|
||||
/*
|
||||
* Copyright (c) 2015, SICS Swedish ICT.
|
||||
* All rights reserved.
|
||||
*
|
||||
* 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 of the Institute 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 INSTITUTE 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 INSTITUTE 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.
|
||||
*
|
||||
* This file is part of the Contiki operating system.
|
||||
*
|
||||
*/
|
||||
|
||||
/**
|
||||
* \file
|
||||
* ringbufindex library. Implements basic support for ring buffers
|
||||
* of any type, as opposed to the core/lib/ringbuf module which
|
||||
* is only for byte arrays. Simply returns index in the ringbuf
|
||||
* rather than actual elements. The ringbuf size must be power of two.
|
||||
* Like the original ringbuf, this module implements atomic put and get.
|
||||
* \author
|
||||
* Simon Duquennoy <simonduq@sics.se>
|
||||
* based on Contiki's core/lib/ringbuf library by Adam Dunkels
|
||||
*/
|
||||
|
||||
#include <string.h>
|
||||
#include "lib/ringbufindex.h"
|
||||
|
||||
/* Initialize a ring buffer. The size must be a power of two */
|
||||
void
|
||||
ringbufindex_init(struct ringbufindex *r, uint8_t size)
|
||||
{
|
||||
r->mask = size - 1;
|
||||
r->put_ptr = 0;
|
||||
r->get_ptr = 0;
|
||||
}
|
||||
/* Put one element to the ring buffer */
|
||||
int
|
||||
ringbufindex_put(struct ringbufindex *r)
|
||||
{
|
||||
/* Check if buffer is full. If it is full, return 0 to indicate that
|
||||
the element was not inserted.
|
||||
|
||||
XXX: there is a potential risk for a race condition here, because
|
||||
the ->get_ptr field may be written concurrently by the
|
||||
ringbufindex_get() function. To avoid this, access to ->get_ptr must
|
||||
be atomic. We use an uint8_t type, which makes access atomic on
|
||||
most platforms, but C does not guarantee this.
|
||||
*/
|
||||
if(((r->put_ptr - r->get_ptr) & r->mask) == r->mask) {
|
||||
return 0;
|
||||
}
|
||||
r->put_ptr = (r->put_ptr + 1) & r->mask;
|
||||
return 1;
|
||||
}
|
||||
/* Check if there is space to put an element.
|
||||
* Return the index where the next element is to be added */
|
||||
int
|
||||
ringbufindex_peek_put(const struct ringbufindex *r)
|
||||
{
|
||||
/* Check if there are bytes in the buffer. If so, we return the
|
||||
first one. If there are no bytes left, we return -1.
|
||||
*/
|
||||
if(((r->put_ptr - r->get_ptr) & r->mask) == r->mask) {
|
||||
return -1;
|
||||
}
|
||||
return (r->put_ptr + 1) & r->mask;
|
||||
}
|
||||
/* Remove the first element and return its index */
|
||||
int
|
||||
ringbufindex_get(struct ringbufindex *r)
|
||||
{
|
||||
int get_ptr;
|
||||
|
||||
/* Check if there are bytes in the buffer. If so, we return the
|
||||
first one and increase the pointer. If there are no bytes left, we
|
||||
return -1.
|
||||
|
||||
XXX: there is a potential risk for a race condition here, because
|
||||
the ->put_ptr field may be written concurrently by the
|
||||
ringbufindex_put() function. To avoid this, access to ->get_ptr must
|
||||
be atomic. We use an uint8_t type, which makes access atomic on
|
||||
most platforms, but C does not guarantee this.
|
||||
*/
|
||||
if(((r->put_ptr - r->get_ptr) & r->mask) > 0) {
|
||||
get_ptr = r->get_ptr;
|
||||
r->get_ptr = (r->get_ptr + 1) & r->mask;
|
||||
return get_ptr;
|
||||
} else {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
/* Return the index of the first element
|
||||
* (which will be removed if calling ringbufindex_peek) */
|
||||
int
|
||||
ringbufindex_peek_get(const struct ringbufindex *r)
|
||||
{
|
||||
/* Check if there are bytes in the buffer. If so, we return the
|
||||
first one. If there are no bytes left, we return -1.
|
||||
*/
|
||||
if(((r->put_ptr - r->get_ptr) & r->mask) > 0) {
|
||||
return (r->get_ptr + 1) & r->mask;
|
||||
} else {
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
/* Return the ring buffer size */
|
||||
int
|
||||
ringbufindex_size(const struct ringbufindex *r)
|
||||
{
|
||||
return r->mask + 1;
|
||||
}
|
||||
/* Return the number of elements currently in the ring buffer */
|
||||
int
|
||||
ringbufindex_elements(const struct ringbufindex *r)
|
||||
{
|
||||
return (r->put_ptr - r->get_ptr) & r->mask;
|
||||
}
|
||||
/* Is the ring buffer full? */
|
||||
int
|
||||
ringbufindex_full(const struct ringbufindex *r)
|
||||
{
|
||||
return ((r->put_ptr - r->get_ptr) & r->mask) == r->mask;
|
||||
}
|
||||
/* Is the ring buffer empty? */
|
||||
int
|
||||
ringbufindex_empty(const struct ringbufindex *r)
|
||||
{
|
||||
return ringbufindex_elements(r) == 0;
|
||||
}
|
||||
72
core/lib/ringbufindex.h
Normal file
72
core/lib/ringbufindex.h
Normal file
@ -0,0 +1,72 @@
|
||||
/*
|
||||
* Copyright (c) 2015, SICS Swedish ICT.
|
||||
* All rights reserved.
|
||||
*
|
||||
* 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 of the Institute 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 INSTITUTE 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 INSTITUTE 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.
|
||||
*
|
||||
* This file is part of the Contiki operating system.
|
||||
*
|
||||
*/
|
||||
|
||||
/**
|
||||
* \file
|
||||
* Header file for the ringbufindex library
|
||||
* \author
|
||||
* Simon Duquennoy <simonduq@sics.se>
|
||||
*/
|
||||
|
||||
#ifndef __RINGBUFINDEX_H__
|
||||
#define __RINGBUFINDEX_H__
|
||||
|
||||
#include "contiki-conf.h"
|
||||
|
||||
struct ringbufindex {
|
||||
uint8_t mask;
|
||||
/* These must be 8-bit quantities to avoid race conditions. */
|
||||
uint8_t put_ptr, get_ptr;
|
||||
};
|
||||
|
||||
/* Initialize a ring buffer. The size must be a power of two */
|
||||
void ringbufindex_init(struct ringbufindex *r, uint8_t size);
|
||||
/* Put one element to the ring buffer */
|
||||
int ringbufindex_put(struct ringbufindex *r);
|
||||
/* Check if there is space to put an element.
|
||||
* Return the index where the next element is to be added */
|
||||
int ringbufindex_peek_put(const struct ringbufindex *r);
|
||||
/* Remove the first element and return its index */
|
||||
int ringbufindex_get(struct ringbufindex *r);
|
||||
/* Return the index of the first element
|
||||
* (which will be removed if calling ringbufindex_peek) */
|
||||
int ringbufindex_peek_get(const struct ringbufindex *r);
|
||||
/* Return the ring buffer size */
|
||||
int ringbufindex_size(const struct ringbufindex *r);
|
||||
/* Return the number of elements currently in the ring buffer */
|
||||
int ringbufindex_elements(const struct ringbufindex *r);
|
||||
/* Is the ring buffer full? */
|
||||
int ringbufindex_full(const struct ringbufindex *r);
|
||||
/* Is the ring buffer empty? */
|
||||
int ringbufindex_empty(const struct ringbufindex *r);
|
||||
|
||||
#endif /* __RINGBUFINDEX_H__ */
|
||||
Loading…
Reference in New Issue
Block a user