diff mbox series

[v3,09/17] lib min_heap: Add min_heap_sift_up()

Message ID 20240406164727.577914-10-visitorckw@gmail.com (mailing list archive)
State Not Applicable, archived
Delegated to: Mike Snitzer
Headers show
Series treewide: Refactor heap related implementation | expand

Commit Message

Kuan-Wei Chiu April 6, 2024, 4:47 p.m. UTC
Add min_heap_sift_up() to sift up the element at index 'idx' in the
heap.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---
 include/linux/min_heap.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Comments

Ian Rogers April 7, 2024, 7:10 p.m. UTC | #1
On Sat, Apr 6, 2024 at 9:48 AM Kuan-Wei Chiu <visitorckw@gmail.com> wrote:
>
> Add min_heap_sift_up() to sift up the element at index 'idx' in the
> heap.
>
> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  include/linux/min_heap.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
> index 9391f7cc9da9..201f59cb3558 100644
> --- a/include/linux/min_heap.h
> +++ b/include/linux/min_heap.h
> @@ -111,6 +111,26 @@ void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
>  #define min_heapify(_heap, _pos, _func, _args) \
>         __min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
>
> +/* Sift up ith element from the heap, O(log2(nr)). */
> +static __always_inline
> +void __min_heap_sift_up(min_heap_char *heap, size_t elem_size, size_t idx,
> +               const struct min_heap_callbacks *func, void *args)
> +{
> +       void *data = heap->data;
> +       size_t parent;
> +
> +       while (idx) {
> +               parent = (idx - 1) / 2;
> +               if (func->less(data + parent * elem_size, data + idx * elem_size, args))
> +                       break;
> +               func->swp(data + parent * elem_size, data + idx * elem_size, args);
> +               idx = parent;
> +       }
> +}
> +
> +#define min_heap_sift_up(_heap, _idx, _func, _args)    \
> +       __min_heap_sift_up((min_heap_char *)_heap, __minheap_obj_size(_heap), _idx, _func, _args)
> +
>  /* Floyd's approach to heapification that is O(nr). */
>  static __always_inline
>  void __min_heapify_all(min_heap_char *heap, size_t elem_size,
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
index 9391f7cc9da9..201f59cb3558 100644
--- a/include/linux/min_heap.h
+++ b/include/linux/min_heap.h
@@ -111,6 +111,26 @@  void __min_heapify(min_heap_char *heap, int pos, size_t elem_size,
 #define min_heapify(_heap, _pos, _func, _args)	\
 	__min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_heap), _func, _args)
 
+/* Sift up ith element from the heap, O(log2(nr)). */
+static __always_inline
+void __min_heap_sift_up(min_heap_char *heap, size_t elem_size, size_t idx,
+		const struct min_heap_callbacks *func, void *args)
+{
+	void *data = heap->data;
+	size_t parent;
+
+	while (idx) {
+		parent = (idx - 1) / 2;
+		if (func->less(data + parent * elem_size, data + idx * elem_size, args))
+			break;
+		func->swp(data + parent * elem_size, data + idx * elem_size, args);
+		idx = parent;
+	}
+}
+
+#define min_heap_sift_up(_heap, _idx, _func, _args)	\
+	__min_heap_sift_up((min_heap_char *)_heap, __minheap_obj_size(_heap), _idx, _func, _args)
+
 /* Floyd's approach to heapification that is O(nr). */
 static __always_inline
 void __min_heapify_all(min_heap_char *heap, size_t elem_size,