关于rt-thread/components/drivers/src/ringbuffer.c的bug

发布于 2015-01-10 12:23:21 浏览：2710 订阅该版

之前用rtt1.1.0在串口接收部分上加了一个dma。现在用1.2.3 。也想要加一个dma。看到1.2.3的串口驱动里加入了ringbuffer。
由于dma也是大批写入。
stm32103x的串口驱动里只有rt_ringbuffer_putchar_force，没有 rt_ringbuffer_put_force。
就想把rt_ringbuffer_put_force移植到串口驱动里。
看到rt_ringbuffer_put_force函数的这里
```  if (rb->buffer_size - rb->write_index > length)
{
        memcpy(&rb->buffer_ptr[rb->write_index], ptr, length);
        rb->write_index += length;

if (old_state == RT_RINGBUFFER_FULL)
            rb->read_index = rb->write_index;

return length;
}```
感觉 if (old_state == RT_RINGBUFFER_FULL)这里的判断有问题。是否应该改为if(length > rt_ringbuffer_space_len(rb))。
还有这里
```
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));

rb->write_mirror = ~rb->write_mirror;
    rb->write_index = length - (rb->buffer_size - rb->write_index);

if (old_state == RT_RINGBUFFER_FULL)
    {
        rb->read_mirror = ~rb->read_mirror;
        rb->read_index = rb->write_index;
    }

if (old_state == RT_RINGBUFFER_FULL)
 {
        rb->read_mirror = ~rb->read_mirror;
        rb->read_index = rb->write_index;
 }```
是否应该改为
```if (length > rt_ringbuffer_space_len(rb))
{
        rb->read_mirror = ~rb->write_mirror;
        rb->read_index = rb->write_index;
}```
因为即使之前环形队列不为空，如果剩余空间不够，也有覆盖的可能。