Function rt_ringbuffer_get

components/drivers/ipc/ringbuffer.c:177–218

* @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. */

 * @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_uint32_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);

/**