Merge pull request #4088 from loogg/mlw

add 'rt_ringbuffer_peak' API

1 files changed, 34 insertions, 0 deletions

diff --git a/components/drivers/src/ringbuffer.c b/components/drivers/src/ringbuffer.c
index c6a491a7cc..88afd19506 100644
--- a/components/drivers/src/ringbuffer.c
+++ b/components/drivers/src/ringbuffer.c
@@ -194,6 +194,40 @@ rt_size_t rt_ringbuffer_get(struct rt_ringbuffer *rb,
 RTM_EXPORT(rt_ringbuffer_get);
 
 /**
+ *  peak data from ring buffer
+ */
+rt_size_t rt_ringbuffer_peak(struct rt_ringbuffer *rb, rt_uint8_t **ptr)
+{
+    RT_ASSERT(rb != RT_NULL);
+
+    *ptr = RT_NULL;
+
+    /* whether has enough data  */
+    rt_size_t size = rt_ringbuffer_data_len(rb);
+
+    /* no data */
+    if (size == 0)
+        return 0;
+
+    *ptr = &rb->buffer_ptr[rb->read_index];
+
+    if(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_peak);
+
+/**
  * put a character into ring buffer
  */
 rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb, const rt_uint8_t ch)