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/*
* File : ringbuffer.c
* This file is part of RT-Thread RTOS
* COPYRIGHT (C) 2012, RT-Thread Development Team
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Change Logs:
* Date Author Notes
* 2012-09-30 Bernard first version.
* 2013-05-08 Grissiom reimplement
*/
#include <rtthread.h>
#include <rtdevice.h>
#include <string.h>
void rt_ringbuffer_init(struct rt_ringbuffer *rb,
rt_uint8_t *pool,
rt_int16_t size)
{
RT_ASSERT(rb != RT_NULL);
RT_ASSERT(size > 0)
/* initialize read and write index */
rb->read_mirror = rb->read_index = 0;
rb->write_mirror = rb->write_index = 0;
/* set buffer pool and size */
rb->buffer_ptr = pool;
rb->buffer_size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);
}
RTM_EXPORT(rt_ringbuffer_init);
rt_size_t rt_ringbuffer_put(struct rt_ringbuffer *rb,
const rt_uint8_t *ptr,
rt_uint16_t length)
{
rt_uint16_t size;
RT_ASSERT(rb != RT_NULL);
/* whether has enough space */
size = RT_RINGBUFFER_EMPTY(rb);
/* no space */
if (size == 0)
return 0;
/* drop some data */
if (size < length)
length = size;
if (rb->buffer_size - rb->write_index > length)
{
/* read_index - write_index = empty space */
memcpy(&rb->buffer_ptr[rb->write_index], ptr, length);
/* this should not cause overflow because there is enough space for
* length of data in current mirror */
rb->write_index += length;
return length;
}
memcpy(&rb->buffer_ptr[rb->write_index],
&ptr[0],
rb->buffer_size - rb->write_index);
memcpy(&rb->buffer_ptr[0],
&ptr[rb->buffer_size - rb->write_index],
length - (rb->buffer_size - rb->write_index));
/* we are going into the other side of the mirror */
rb->write_mirror = ~rb->write_mirror;
rb->write_index = length - (rb->buffer_size - rb->write_index);
return length;
}
RTM_EXPORT(rt_ringbuffer_put);
/**
* get data from ring buffer
*/
rt_size_t rt_ringbuffer_get(struct rt_ringbuffer *rb,
rt_uint8_t *ptr,
rt_uint16_t length)
{
rt_size_t size;
RT_ASSERT(rb != RT_NULL);
/* whether has enough data */
size = RT_RINGBUFFER_SIZE(rb);
/* no data */
if (size == 0)
return 0;
/* less data */
if (size < length)
length = size;
if (rb->buffer_size - rb->read_index > length)
{
/* copy all of data */
memcpy(ptr, &rb->buffer_ptr[rb->read_index], length);
/* this should not cause overflow because there is enough space for
* length of data in current mirror */
rb->read_index += length;
return length;
}
memcpy(&ptr[0],
&rb->buffer_ptr[rb->read_index],
rb->buffer_size - rb->read_index);
memcpy(&ptr[rb->buffer_size - rb->read_index],
&rb->buffer_ptr[0],
length - (rb->buffer_size - rb->read_index));
/* we are going into the other side of the mirror */
rb->read_mirror = ~rb->read_mirror;
rb->read_index = length - (rb->buffer_size - rb->read_index);
return length;
}
RTM_EXPORT(rt_ringbuffer_get);
/**
* put a character into ring buffer
*/
rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb, const rt_uint8_t ch)
{
RT_ASSERT(rb != RT_NULL);
/* whether has enough space */
if (!RT_RINGBUFFER_EMPTY(rb))
return 0;
rb->buffer_ptr[rb->write_index] = ch;
/* flip mirror */
if (rb->write_index == rb->buffer_size-1)
{
rb->write_mirror = ~rb->write_mirror;
rb->write_index = 0;
}
else
{
rb->write_index++;
}
return 1;
}
RTM_EXPORT(rt_ringbuffer_putchar);
/**
* get a character from a ringbuffer
*/
rt_size_t rt_ringbuffer_getchar(struct rt_ringbuffer *rb, rt_uint8_t *ch)
{
RT_ASSERT(rb != RT_NULL);
/* ringbuffer is empty */
if (!RT_RINGBUFFER_SIZE(rb))
return 0;
/* put character */
*ch = rb->buffer_ptr[rb->read_index];
if (rb->read_index == rb->buffer_size-1)
{
rb->read_mirror = ~rb->read_mirror;
rb->read_index = 0;
}
else
{
rb->read_index++;
}
return 1;
}
RTM_EXPORT(rt_ringbuffer_getchar);
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