rt-thread/components/drivers/ipc/ringbuffer.c

468 lines
12 KiB
C

/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2012-09-30 Bernard first version.
* 2013-05-08 Grissiom reimplement
* 2016-08-18 heyuanjie add interface
* 2021-07-20 arminker fix write_index bug in function rt_ringbuffer_put_force
* 2021-08-14 Jackistang add comments for function interface.
*/
#include <rtthread.h>
#include <rtdevice.h>
#include <string.h>
rt_inline enum rt_ringbuffer_state rt_ringbuffer_status(struct rt_ringbuffer *rb)
{
if (rb->read_index == rb->write_index)
{
if (rb->read_mirror == rb->write_mirror)
return RT_RINGBUFFER_EMPTY;
else
return RT_RINGBUFFER_FULL;
}
return RT_RINGBUFFER_HALFFULL;
}
/**
* @brief Initialize the ring buffer object.
*
* @param rb A pointer to the ring buffer object.
* @param pool A pointer to the buffer.
* @param size The size of the buffer in bytes.
*/
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);
/**
* @brief Put a block of data into the ring buffer. If the capacity of ring buffer is insufficient, it will discard out-of-range data.
*
* @param rb A pointer to the ring buffer object.
* @param ptr A pointer to the data buffer.
* @param length The size of data in bytes.
*
* @return Return the data size we put into the ring buffer.
*/
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_space_len(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 */
rt_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;
}
rt_memcpy(&rb->buffer_ptr[rb->write_index],
&ptr[0],
rb->buffer_size - rb->write_index);
rt_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);
/**
* @brief Put a block of data into the ring buffer. If the capacity of ring buffer is insufficient, it will overwrite the existing data in the ring buffer.
*
* @param rb A pointer to the ring buffer object.
* @param ptr A pointer to the data buffer.
* @param length The size of data in bytes.
*
* @return Return the data size we put into the ring buffer.
*/
rt_size_t rt_ringbuffer_put_force(struct rt_ringbuffer *rb,
const rt_uint8_t *ptr,
rt_uint16_t length)
{
rt_uint16_t space_length;
RT_ASSERT(rb != RT_NULL);
space_length = rt_ringbuffer_space_len(rb);
if (length > rb->buffer_size)
{
ptr = &ptr[length - rb->buffer_size];
length = rb->buffer_size;
}
if (rb->buffer_size - rb->write_index > length)
{
/* read_index - write_index = empty space */
rt_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;
if (length > space_length)
rb->read_index = rb->write_index;
return length;
}
rt_memcpy(&rb->buffer_ptr[rb->write_index],
&ptr[0],
rb->buffer_size - rb->write_index);
rt_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);
if (length > space_length)
{
if (rb->write_index <= rb->read_index)
rb->read_mirror = ~rb->read_mirror;
rb->read_index = rb->write_index;
}
return length;
}
RTM_EXPORT(rt_ringbuffer_put_force);
/**
* @brief Get data from the ring buffer.
*
* @param rb A pointer to the ring buffer.
* @param ptr A pointer to the data buffer.
* @param length The size of the data we want to read from the ring buffer.
*
* @return Return the data size we read from the 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_data_len(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 */
rt_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;
}
rt_memcpy(&ptr[0],
&rb->buffer_ptr[rb->read_index],
rb->buffer_size - rb->read_index);
rt_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);
/**
* @brief Get the first readable byte of the ring buffer.
*
* @param rb A pointer to the ringbuffer.
* @param ptr When this function return, *ptr is a pointer to the first readable byte of the ring buffer.
*
* @note It is recommended to read only one byte, otherwise it may cause buffer overflow.
*
* @return Return the size of the ring buffer.
*/
rt_size_t rt_ringbuffer_peek(struct rt_ringbuffer *rb, rt_uint8_t **ptr)
{
rt_size_t size;
RT_ASSERT(rb != RT_NULL);
*ptr = RT_NULL;
/* whether has enough data */
size = rt_ringbuffer_data_len(rb);
/* no data */
if (size == 0)
return 0;
*ptr = &rb->buffer_ptr[rb->read_index];
if ((rt_size_t)(rb->buffer_size - rb->read_index) > size)
{
rb->read_index += size;
return size;
}
size = 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 = 0;
return size;
}
RTM_EXPORT(rt_ringbuffer_peek);
/**
* @brief Put a byte into the ring buffer. If ring buffer is full, this operation will fail.
*
* @param rb A pointer to the ring buffer object.
* @param ch A byte put into the ring buffer.
*
* @return Return the data size we put into the ring buffer. The ring buffer is full if returns 0. Otherwise, it will return 1.
*/
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_space_len(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);
/**
* @brief Put a byte into the ring buffer. If ring buffer is full, it will discard an old data and put into a new data.
*
* @param rb A pointer to the ring buffer object.
* @param ch A byte put into the ring buffer.
*
* @return Return the data size we put into the ring buffer. Always return 1.
*/
rt_size_t rt_ringbuffer_putchar_force(struct rt_ringbuffer *rb, const rt_uint8_t ch)
{
enum rt_ringbuffer_state old_state;
RT_ASSERT(rb != RT_NULL);
old_state = rt_ringbuffer_status(rb);
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;
if (old_state == RT_RINGBUFFER_FULL)
{
rb->read_mirror = ~rb->read_mirror;
rb->read_index = rb->write_index;
}
}
else
{
rb->write_index++;
if (old_state == RT_RINGBUFFER_FULL)
rb->read_index = rb->write_index;
}
return 1;
}
RTM_EXPORT(rt_ringbuffer_putchar_force);
/**
* @brief Get a byte from the ring buffer.
*
* @param rb The pointer to the ring buffer object.
* @param ch A pointer to the buffer, used to store one byte.
*
* @return 0 The ring buffer is empty.
* @return 1 Success
*/
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_data_len(rb))
return 0;
/* put byte */
*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);
/**
* @brief Get the size of data in the ring buffer in bytes.
*
* @param rb The pointer to the ring buffer object.
*
* @return Return the size of data in the ring buffer in bytes.
*/
rt_size_t rt_ringbuffer_data_len(struct rt_ringbuffer *rb)
{
switch (rt_ringbuffer_status(rb))
{
case RT_RINGBUFFER_EMPTY:
return 0;
case RT_RINGBUFFER_FULL:
return rb->buffer_size;
case RT_RINGBUFFER_HALFFULL:
default:
{
rt_size_t wi = rb->write_index, ri = rb->read_index;
if (wi > ri)
return wi - ri;
else
return rb->buffer_size - (ri - wi);
}
}
}
RTM_EXPORT(rt_ringbuffer_data_len);
/**
* @brief Reset the ring buffer object, and clear all contents in the buffer.
*
* @param rb A pointer to the ring buffer object.
*/
void rt_ringbuffer_reset(struct rt_ringbuffer *rb)
{
RT_ASSERT(rb != RT_NULL);
rb->read_mirror = 0;
rb->read_index = 0;
rb->write_mirror = 0;
rb->write_index = 0;
}
RTM_EXPORT(rt_ringbuffer_reset);
#ifdef RT_USING_HEAP
/**
* @brief Create a ring buffer object with a given size.
*
* @param size The size of the buffer in bytes.
*
* @return Return a pointer to ring buffer object. When the return value is RT_NULL, it means this creation failed.
*/
struct rt_ringbuffer *rt_ringbuffer_create(rt_uint16_t size)
{
struct rt_ringbuffer *rb;
rt_uint8_t *pool;
RT_ASSERT(size > 0);
size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);
rb = (struct rt_ringbuffer *)rt_malloc(sizeof(struct rt_ringbuffer));
if (rb == RT_NULL)
goto exit;
pool = (rt_uint8_t *)rt_malloc(size);
if (pool == RT_NULL)
{
rt_free(rb);
rb = RT_NULL;
goto exit;
}
rt_ringbuffer_init(rb, pool, size);
exit:
return rb;
}
RTM_EXPORT(rt_ringbuffer_create);
/**
* @brief Destroy the ring buffer object, which is created by rt_ringbuffer_create() .
*
* @param rb A pointer to the ring buffer object.
*/
void rt_ringbuffer_destroy(struct rt_ringbuffer *rb)
{
RT_ASSERT(rb != RT_NULL);
rt_free(rb->buffer_ptr);
rt_free(rb);
}
RTM_EXPORT(rt_ringbuffer_destroy);
#endif