ringbuffer: add "has_data" helper function

The ringbuffers are opaque, so the only way to check if a buffer has data is to add this simple helper function. Signed-off-by: Chris Guikema <[email protected]>
seL4 · Oct 26, 2022 · 96170d3 · 96170d3
1 parent 7c0f71e
commit 96170d3
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diff --git a/libringbuffer/include/ringbuffer/ringbuffer.h b/libringbuffer/include/ringbuffer/ringbuffer.h
@@ -29,6 +29,12 @@ typedef struct ringbuffer ringbuffer_t;
  */
 ringbuffer_t *rb_new(void *base, size_t size);
 
+/* Check if ring buffer has data
+ *  r - Buffer to check
+ * Returns Boolean representing if ringbuffer has data.
+ */
+int rb_has_data(ringbuffer_t *r);
+
 /* Send a byte.
  *  r - Buffer to send via.
  *  c - Byte to send.

diff --git a/libringbuffer/src/ringbuffer.c b/libringbuffer/src/ringbuffer.c
@@ -28,6 +28,11 @@ ringbuffer_t *rb_new(void *base, size_t size)
     return r;
 }
 
+int rb_has_data(ringbuffer_t *r)
+{
+    return (r->base[r->offset] == 0);
+}
+
 void rb_transmit_byte(ringbuffer_t *r, unsigned char c)
 {
     /* We can't send 0s. */