rb: allow to remove data from a ring buffer

we provide two new ways to remove data from a ring_buffer

rb_remove(rb, n)
or
rb_get(rb, NULL, n)

closes #2

2 files changed, 15 insertions, 2 deletions

diff --git a/rb.h b/rb.h
index f66dba8..5b1e0e1 100644
--- a/rb.h
+++ b/rb.h
@@ -46,4 +46,13 @@ size_t rb_get(t_rb *rb, void *dest, size_t n);
  */
 size_t rb_peek(const t_rb *ring_buffer, void *dest, size_t size);
 
+/*
+ * remove a maximum of n bytes from the ring buffer pointed to by rb
+ * the functions returns the number of bytes actually removed
+ */
+static inline size_t rb_remove(t_rb *rb, size_t n)
+{
+    return rb_get(rb, NULL, n);
+}
+
 #endif /* RING_BUFFER_H */
diff --git a/src/rb.c b/src/rb.c
index 505c373..ce269fb 100644
--- a/src/rb.c
+++ b/src/rb.c
@@ -96,7 +96,9 @@ size_t rb_peek(const t_rb *rb, void *dest, size_t n)
         /* do not try to retrieve too much data */
         size = MIN(n, rb_get_size(rb) - rb->off_r);
 
-        memcpy(dest, &rb->buffer[rb->off_r], size);
+        if (dest != NULL) {
+            memcpy(dest, &rb->buffer[rb->off_r], size);
+        }
 
         dest += size;
         n    -= size;
@@ -106,7 +108,9 @@ size_t rb_peek(const t_rb *rb, void *dest, size_t n)
 
     size2 = MIN(n, (size_t)(rb->off_w - offset));
 
-    memcpy(dest, &rb->buffer[offset], size2);
+    if (dest != NULL) {
+        memcpy(dest, &rb->buffer[offset], size2);
+    }
 
     return size + size2;
 }